JP2008065171A - Electrophotographic photoreceptor, process cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor in which variation in electrical properties is sufficiently reduced, and also, the generation of picture defects can be sufficiently suppressed even if being repeatedly used, to provide a process cartridge, and to provide an electrophotographic equipment. <P>SOLUTION: In the electrophotographic photoreceptor 110, an under coating layer 2b comprising electrically conductive particles and a photosensitive layer 4 are provided on an electrically conductive substrate 1 in this order. The space between the under coating layer 2b and the photosensitive layer 4 is provided with a silane coupling agent-containing layer 3b containing the silane coupling agent at a concentration higher than that in the under coating layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member, a process cartridge, and an image forming apparatus.

  The electrophotographic system is used in electrophotographic apparatuses such as copying machines and laser beam printers because it can obtain high-quality printing at high speed. As the electrophotographic photosensitive member used in this electrophotographic apparatus, an organic electrophotographic photosensitive member using an organic photoconductive material is mainly used, and the structure of the electrophotographic photosensitive member includes a layer containing a charge generating material ( The performance has been improved by changing to a function-separated electrophotographic photosensitive member in which a charge generation layer) and a layer containing a charge transport material (charge transport layer) are laminated.

  In the case of this function-separated electrophotographic photosensitive member, there is a case where an undercoat layer is first formed on an aluminum substrate (conductive substrate), and then a photosensitive layer comprising a charge generation layer and a charge transport layer is formed. Many.

  In this case, there are many parts that depend on the charge generation layer and the charge transport layer as well as the undercoat layer for improving the stability and environmental stability of the electrophotographic photoreceptor when it is used repeatedly. There is a demand for a subbing layer with less. In particular, due to increasing awareness of environmental issues in recent years, there is an increasing expectation for the development of a long-life electrophotographic photoreceptor, and it is essential to improve the stability of electrical characteristics and image quality when used repeatedly over a long period of time. .

  In addition, the undercoat layer plays a major role in preventing image quality defects. In addition to the function of preventing the occurrence of fogging by maintaining the charge blocking property at the time of charging, the substrate has defects and dirt or the charge generation layer. The undercoat layer is an important functional layer in order to suppress image quality defects caused by coating layer defects or unevenness in the upper layer.

  Further, in recent years, contact charging type charging devices that generate less ozone instead of corotron have been used in electrophotographic devices. Due to the local high electric field applied during contact charging to locally deteriorated portions of the electrophotographic photosensitive member, In some cases, a pinhole is generated, resulting in an image quality defect such as a black spot.

  This pinhole leak may occur due to a coating film defect of the above-described electrophotographic photosensitive member itself, but in addition to this, conductive foreign matter generated in the electrophotographic apparatus is contacted or electrophotographic in the electrophotographic photosensitive member. It may occur because it penetrates into the photoreceptor and facilitates the formation of a conductive path between the contact charging device and the conductive substrate. In a noticeable case, foreign matter mixed from other members in the electrophotographic apparatus or dust mixed in the electrophotographic apparatus may pierce the electrophotographic photosensitive member to form a leak point from the contact charging device.

  In order to cope with such a problem, pinhole leakage is prevented from occurring at the piercing portion of the conductive foreign material by increasing the thickness of the undercoat layer to 10 μm or more.

  In order to design a subbing layer that can improve the stability and environmental stability during repeated use of an electrophotographic photosensitive member, and further prevent image quality defects, Many studies have been made.

  For example, recently, a method has been proposed in which conductive fine powder surface-treated with a silane coupling agent or the like is dispersed in an undercoat layer to achieve a balance between conductivity and charge blocking properties (for example, Patent Document 1). See). In addition, a technique for optimizing the surface treatment method of the silane coupling agent to maximize the ability of the silane coupling agent has also been proposed (see, for example, Patent Document 2). Among the silane coupling agents, amine-based silane coupling agents are suitable materials for forming an energy barrier between the undercoat layer and the photosensitive layer, and there are few obstacles to electrophotographic characteristics and safety. It is also excellent in availability and cost (see, for example, Patent Documents 3 to 5).

  All of these techniques are considered to have an aim of appropriately securing the conductivity of the undercoat layer and creating an appropriate hole injection barrier from the undercoat layer to the photosensitive layer.

Japanese Patent Application Laid-Open No. 08-166679 JP 11-133649 A JP 07-175249 A JP 08-44097 A JP 09-197701 A

  However, even with the above prior art, there is a limit to ensuring the stability of electrical characteristics and image quality during repeated use, and there is room for further improvement in order to further extend the use period of the electrophotographic photosensitive member. is there. That is, when considering the prevention of image quality defects such as fogging and black spots for a long period of time, the undercoat layer should have high conductivity while preventing hole injection from the undercoat layer to the photosensitive layer. desirable. However, according to the studies by the present inventors, in the conventional photoreceptor having the undercoat layer, the silane coupling agent is likely to be a hole trap if an attempt is made to increase the hole injection blocking property by increasing the amount of the silane coupling agent. It has been found that the residual potential tends to increase during repeated use. Further, it has been found by the present inventors that such a tendency is more likely to occur with a silane coupling agent having a higher hole injection blocking property.

  Therefore, the present invention has been made in view of the problems of the above-described conventional technology, and even when it is repeatedly used, fluctuations in electrical characteristics are sufficiently small and occurrence of image quality defects can be sufficiently suppressed. An object is to provide an electrophotographic photosensitive member, a process cartridge, and an electrophotographic apparatus.

  In order to solve the above-mentioned problems, the present invention provides an electrophotographic photosensitive member in which an undercoat layer containing conductive particles and a photosensitive layer are provided in this order on a conductive substrate, the undercoat layer A silane coupling agent-containing layer containing a silane coupling agent at a higher concentration than the undercoat layer is provided between the photosensitive layer and the photosensitive layer. The silane coupling agent referred to here is a silane coupling agent bonded by reacting with another compound, a hydrolyzed silane coupling agent, and a hydrolyzed and reacted with another compound. Silane coupling agents are included.

  The present invention is also an electrophotographic photosensitive member in which an undercoat layer containing conductive particles and a photosensitive layer are provided in this order on a conductive substrate, and on the photosensitive layer side of the undercoat layer, Provided is an electrophotographic photosensitive member characterized in that a silane coupling agent is contained at a higher concentration than the conductive substrate side of the undercoat layer. The silane coupling agent referred to here is a silane coupling agent bonded by reacting with another compound, a hydrolyzed silane coupling agent, and a hydrolyzed and reacted with another compound. Silane coupling agents are included.

  According to these electrophotographic photoreceptors, even if they are repeatedly used, fluctuations in electrical characteristics are sufficiently small, and the occurrence of image quality defects can be sufficiently suppressed.

  The reason why the above effect can be obtained by the electrophotographic photosensitive member of the present invention is not necessarily clear, but the present inventors infer as follows. First, the inventors of the present invention simply used the silane coupling agent as the undercoat layer because the silane coupling agent present in the region of the undercoat layer far from the photosensitive layer does not greatly contribute to the formation of the hole injection barrier. It is considered that the hole trap sites increase in the undercoat layer in the method of increasing the hole injection blocking property by distributing at a high concentration. Therefore, in the case of the above conventional electrophotographic photosensitive member, it is considered difficult to suppress the increase of the residual potential while ensuring the hole injection preventing property. In contrast, in the case of the electrophotographic photoreceptor of the present invention, the silane coupling agent is present with a density difference between a position close to the photosensitive layer and a position far from the photosensitive layer, or the silane coupling agent is present in the photosensitive layer. As a result, it is possible to achieve both the formation of a hole injection barrier and the reduction of the hole trap site, thereby sufficiently increasing the residual potential and generating image quality defects even when used repeatedly. The present inventors speculate that suppression was achieved.

  Further, according to the electrophotographic photosensitive member of the present invention, not only image quality defects such as fogging and black spots due to hole leakage but also ghosting can be prevented, so that higher image quality can be achieved than before. It becomes possible. This is presumably because the electron injection property from the photosensitive layer to the undercoat layer could be improved because the silane coupling agent can be present near the photosensitive layer at a high concentration.

  In the electrophotographic photoreceptor of the present invention, the silane coupling agent is preferably a silane coupling agent having an amino group. In this case, it is possible to further improve the hole injection preventing property from the undercoat layer to the photosensitive layer while sufficiently suppressing an increase in the residual potential of the photosensitive member, so that an image with good image quality can be further stabilized over a long period of time. Can be formed.

  In the electrophotographic photoreceptor of the present invention, it is preferable that the undercoat layer further contains an electron-accepting substance from the viewpoint of further improving the stability of image quality and electrical characteristics during repeated use.

  The electron accepting substance is preferably a compound having anthraquinone as a basic skeleton. The undercoat layer contains an anthraquinone electron-accepting substance, which further improves the electron injection properties from the photosensitive layer to the undercoat layer, and can more effectively prevent the occurrence of image quality defects such as ghosts. The stability of image quality and electrical characteristics during use can be improved synergistically.

  Furthermore, it is preferable that the compound having anthraquinone as a basic skeleton is a hydroxyanthraquinone compound or an aminoanthraquinone compound from the viewpoint of obtaining the above effect more reliably.

  In the electrophotographic photoreceptor of the present invention, the conductive particles contained in the undercoat layer are preferably metal oxides.

  The metal oxide is preferably at least one metal oxide selected from the group consisting of zinc oxide, titanium oxide, aluminum oxide, and tin oxide. These metal oxides have appropriate electrical conductivity required for the undercoat layer, and the hydrate on the surface of the metal oxide has a high affinity with the silane coupling agent, stabilizing the silane coupling agent. Can be made.

  In the electrophotographic photoreceptor of the present invention, the photosensitive layer preferably has a charge generation layer, and the charge generation layer preferably contains at least one of a phthalocyanine pigment and an azo pigment.

  When the charge generation layer includes a phthalocyanine pigment, the phthalocyanine pigment is at least one selected from the group consisting of a hydroxygallium phthalocyanine pigment, a chlorogallium phthalocyanine pigment, an oxotitanyl phthalocyanine pigment, and a metal-free phthalocyanine pigment. preferable.

  The electrophotographic photoreceptor of the present invention preferably has an outermost layer containing fluorine resin particles. The outermost layer means a layer located on the side farthest from the conductive substrate.

  The present invention also provides the electrophotographic photosensitive member of the present invention, a charging means for charging the electrophotographic photosensitive member, and the electrostatic latent image formed on the electrophotographic photosensitive member is developed with toner to form a toner image. And at least one selected from the group consisting of a cleaning unit for removing toner remaining on the surface of the electrophotographic photosensitive member.

  According to the process cartridge of the present invention, by using the electrophotographic photosensitive member of the present invention, it is possible to sufficiently prevent the occurrence of image quality defects and to sufficiently suppress the increase in the residual potential of the photosensitive member due to repeated use. High quality images can be obtained.

  When the process cartridge of the present invention includes a charging unit, the charging unit is preferably a contact charging device that contacts the electrophotographic photosensitive member to charge the electrophotographic photosensitive member.

  The present invention also provides an electrophotographic photosensitive member according to the present invention, a charging unit for charging the electrophotographic photosensitive member, an exposure unit for forming an electrostatic latent image on the charged electrophotographic photosensitive member, An image forming apparatus comprising: a developing unit for developing an electrostatic latent image with toner to form a toner image; and a transfer unit for transferring the toner image from an electrophotographic photosensitive member to a transfer target. provide.

  According to the image forming apparatus of the present invention, by using the electrophotographic photosensitive member of the present invention, it is possible to sufficiently prevent the occurrence of image quality defects and sufficiently suppress the increase in the residual potential of the photosensitive member due to repeated use. High quality images.

  In the image forming apparatus of the present invention, the charging unit is preferably a contact charging device that contacts the electrophotographic photosensitive member to charge the electrophotographic photosensitive member.

  The image forming apparatus of the present invention preferably further includes an intermediate transfer unit that transfers an image formed on the electrophotographic photosensitive member.

  According to the present invention, it is possible to provide an electrophotographic photosensitive member, a process cartridge, and an electrophotographic apparatus that are sufficiently small in electrical characteristics even when used repeatedly and that can sufficiently suppress the occurrence of image quality defects. it can.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or corresponding elements are denoted by the same reference numerals, and redundant description is omitted.

<Electrophotographic photoreceptor>
FIG. 1 is a schematic cross-sectional view showing a preferred embodiment of the electrophotographic photosensitive member of the present invention. An electrophotographic photoreceptor 100 shown in FIG. 1 includes a conductive substrate 1, an undercoat layer 2 a, a photosensitive layer 4, and a protective layer 7. On the photosensitive layer side of the undercoat layer 2a, a silane coupling agent is contained at a higher concentration than the conductive substrate side of the undercoat layer 2b. In this specification, the photosensitive layer side portion of the undercoat layer 2a containing the silane coupling agent at a high concentration is referred to as a high concentration silane coupling agent-containing region 3a. The photosensitive layer 4 has a structure in which a charge generation layer 5 and a charge transport layer 6 are laminated in this order on the undercoat layer 2a.

  FIG. 2 is a schematic cross-sectional view showing another preferred embodiment of the electrophotographic photosensitive member of the present invention. An electrophotographic photoreceptor 100 shown in FIG. 2 includes a conductive substrate 1, an undercoat layer 2b, a silane coupling agent-containing layer 3b, a photosensitive layer 4, and a protective layer 7. The silane coupling agent-containing layer 3b is a layer containing a silane coupling agent at a higher concentration than the undercoat layer 2b. The photosensitive layer 4 has a structure in which a charge generation layer 5 and a charge transport layer 6 are laminated in this order on a silane coupling agent-containing layer 3b.

  The electrophotographic photoreceptors 100 and 110 shown in FIGS. 1 and 2 are provided with a photosensitive layer 4 whose functions are separated into a charge generation layer 5 and a charge transport layer 6, and include a charge generation material and a charge transport material. It may be contained in the same layer (single-layer type photosensitive layer). In the electrophotographic photoreceptors 100 and 110 shown in FIGS. 1 and 2, the order of stacking the charge generation layer 5 and the charge transport layer 6 constituting the photosensitive layer 4 may be reversed. Further, in the electrophotographic photoreceptors 100 and 110 shown in FIGS. 1 and 2, the protective layer 7 is not necessarily provided.

  Hereinafter, each element will be described based on the electrophotographic photoreceptors 100 and 110 shown in FIGS.

  Examples of the conductive substrate 1 include metal drums such as aluminum, copper, iron, stainless steel, zinc, and nickel; aluminum, copper, gold, silver, platinum, palladium, and the like on a substrate such as a sheet, paper, plastic, and glass. A metal such as titanium, nickel-chromium, stainless steel, or indium, or a conductive metal compound such as indium oxide or tin oxide is vapor-deposited; a metal foil laminated on the base material or carbon black; Indium oxide, tin oxide, antimony oxide powder, metal powder, copper iodide and the like are dispersed in a binder resin and subjected to a conductive treatment by coating it;

  The shape of the conductive substrate 1 is not limited to a drum shape, and may be a sheet shape or a plate shape. In addition, when the conductive substrate 1 is a metal pipe, the surface may be left as it is, or a process such as mirror cutting, etching, anodizing, rough cutting, centerless grinding, sand blasting, wet honing, etc. may be performed in advance. It may be done.

  Next, the undercoat layer 2a in the electrophotographic photoreceptor 100 shown in FIG. 1 will be described.

  In the electrophotographic photoreceptor 100, the undercoat layer 2a is a layer containing at least conductive particles and a silane coupling agent, and the photosensitive layer 4 side has a higher silane coupling agent than the conductive substrate 1 side. A high concentration content region 3a containing a silane coupling agent contained at a concentration is formed. In the undercoat layer 2a, the high concentration silane coupling agent region 3a may not be clearly separated from other regions. That is, in the cross section obtained by cutting the undercoat layer 2a along the surface along the stacking direction, the concentration distribution of the silane coupling agent is higher in the vicinity of the interface with the photosensitive layer 4 than in the vicinity of the interface with the conductive substrate 1. It only has to be. The concentration of the silane coupling agent in the undercoat layer 2a may gradually increase from the vicinity of the interface with the conductive substrate 1 to the vicinity of the interface with the photosensitive layer 4, and the concentration rapidly increases from a predetermined position. It may be.

  Further, the undercoat layer 2a of the present embodiment contains a binder resin.

  As the conductive particles contained in the undercoat layer 2a, metal oxide fine particles are preferably used. By including the metal oxide fine particles in the undercoat layer 2a, for example, even when the undercoat layer 2a is thickened, the resistance increase of the undercoat layer 2a can be controlled.

As the metal oxide fine particles, powders having a volume resistivity in the range of 1 × 10 ² to 1 × 10 ¹¹ Ω · cm are preferably used. The reason is that the undercoat layer 2a needs to have an appropriate resistance for obtaining leak resistance. In addition, if the volume resistivity of the metal oxide fine particles is lower than 1 × 10 ² Ω · cm, it tends to be difficult to obtain sufficient leakage resistance. If the volume resistivity is higher than 1 × 10 ¹¹ Ω · cm, the residual potential increases. It tends to be easier.

  Examples of the metal oxide fine particles include metal oxides such as tin oxide, titanium oxide, zinc oxide, zirconium oxide, and aluminum oxide. Of these, zinc oxide is particularly preferably used. Of these, metal oxide fine particles having a volume resistivity within the above range are preferably used. Furthermore, in this embodiment, it is preferable that the undercoat layer 2a contains one or more of tin oxide, titanium oxide, zinc oxide, and aluminum oxide as a conductive particle.

As the metal oxide fine particles, those having different surface treatments or those having different particle diameters may be used in combination of two or more. As the metal oxide fine particles, those having a specific surface area of 10 m ² / g or more are preferably used. Those having a specific surface area value of 10 m ² / g or less tend to cause a decrease in chargeability and tend to make it difficult to obtain good electrophotographic characteristics. Furthermore, the volume average particle diameter of the metal oxide particles is preferably in the range of 50 to 200 nm.

  The metal oxide fine particles can be contained in the undercoat layer 2a after being subjected to a surface treatment. Any surface treatment agent may be used as long as it has desired characteristics, and can be selected from known materials. For example, a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, a surfactant, and the like can be given. In particular, silane coupling agents are preferably used because they give good electrophotographic characteristics. Furthermore, a silane coupling agent having an amino group is more preferably used because the volume resistance of the layer can be appropriately adjusted and the environmental fluctuation of the resistance can be reduced.

  Any silane coupling agent having an amino group can be used as long as it can obtain desired electrophotographic photoreceptor characteristics. Specific examples include γ-aminopropyltriethoxysilane, N-β-. (Aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, etc. However, it is not limited to these.

  Moreover, 2 or more types of silane coupling agents can also be mixed and used. Examples of the silane coupling agent that can be used in combination with the above-mentioned silane coupling agent having an amino group include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl)- γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltri Examples include methoxysilane, etc. The present invention is not limited to.

  Examples of titanate coupling agents include isopropyl triisostearoyl titanate, bis (dioctyl pyrophosphate), isopropyl tri (N-aminoethyl-aminoethyl) titanate, and the like.

  Examples of the aluminate coupling agent include acetoalkoxyaluminum diisopropylate.

  When a silane coupling agent, a titanate coupling agent, or an aluminum coupling agent is used as the surface treatment agent for the metal oxide fine particles, these can be used alone or in combination of two or more.

  As the surface treatment method, any known method can be used, but a dry method or a wet method can be used.

  For example, when surface treatment is performed by a dry method, a silane coupling agent dissolved directly or in an organic solvent is dropped while stirring metal oxide fine particles with a mixer having a large shearing force, together with dry air or nitrogen gas It is uniformly processed by spraying. The addition or spraying is preferably performed at a temperature below the boiling point of the solvent. Spraying at a temperature equal to or higher than the boiling point of the solvent is not preferred because it causes the solvent to evaporate before being stirred uniformly, causing the silane coupling agent to locally accumulate and making uniform processing difficult. After addition or spraying, baking can be performed at 100 ° C. or higher. Baking can be carried out in an arbitrary range as long as the temperature and time allow the desired electrophotographic characteristics to be obtained.

  As a wet method, the metal oxide fine particles are stirred in a solvent, dispersed using ultrasonic waves, a sand mill, an attritor, a ball mill, etc., added with a silane coupling agent solution and stirred or dispersed, and then the solvent is removed. Uniformly processed. The solvent removal method is distilled off by filtration or distillation. After removing the solvent, baking can be performed at 100 ° C. or higher. Baking can be carried out in an arbitrary range as long as the temperature and time allow the desired electrophotographic characteristics to be obtained. In the wet method, the water containing metal oxide fine particles can be removed before adding the surface treatment agent. For example, a method of removing with stirring and heating in the solvent used for the surface treatment, removing by azeotroping with the solvent. It is also possible to use a method of

  As mentioned above, although the surface treatment method in a silane coupling agent was described, surface treatments, such as a titanate coupling agent and an aluminum coupling agent, can also be surface-treated by the same method.

  The amount of the silane coupling agent relative to the metal oxide particles in the undercoat layer 2a can be arbitrarily set as long as desired electrophotographic characteristics can be obtained.

  The undercoat layer 2a is preferably composed of the above-described metal oxide fine particles and a binder resin.

  As the silane coupling agent contained in the undercoat layer 2a, a known silane coupling agent can be used, and the above-described silane coupling agent having an amino group is preferably used. In the present embodiment, the silane coupling agent contained in the undercoat layer 2a includes a silane coupling agent that reacts with and binds to another compound, is hydrolyzed and adheres to another compound, or another compound. Also included are reactively bonded silane coupling agents. More specifically, examples include a silane coupling agent as a surface treatment agent for the metal oxide fine particles, and a silane coupling agent that reacts and binds to a binder resin or an electron-accepting substance described later.

  As the binder resin contained in the undercoat layer 2a, any known resin can be used as long as it can form a good film and can obtain desired characteristics. For example, acetal such as polyvinyl butyral can be used. Resin, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin , Using known polymer resin compounds such as silicone-alkyd resin, phenol resin, phenol-formaldehyde resin, melamine resin, urethane resin, charge transport resin having a charge transport group, or conductive resin such as polyaniline, etc. CanAmong them, a resin insoluble in the upper coating solvent is preferably used, and in particular, a butyral resin, a phenol resin, a phenol-formaldehyde resin, a melamine resin, a urethane resin, an epoxy resin, and the like are preferably used.

  The undercoat layer 2a preferably further contains an electron accepting substance. Thereby, the electron transfer from the photosensitive layer 4 to the undercoat layer 2a becomes smooth, and the effect of suppressing the increase in the residual potential due to repeated use can be further enhanced.

  As the electron-accepting substance, any substance can be used as long as the desired characteristics can be obtained. In particular, a compound having a quinone group is preferably used, and a compound having an anthraquinone structure is more preferably used.

  In the present embodiment, a compound having a group capable of reacting with and binding to the metal oxide fine particles is preferable. As a compound having a group capable of reacting with and binding to a metal oxide, a compound having a hydroxyl group or a quinone group is preferable, and a compound having an anthraquinone structure as a quinone group is more preferable. Furthermore, in this embodiment, an electron accepting substance having an anthraquinone structure having a hydroxyl group is preferably used. Examples of the electron accepting substance having an anthraquinone structure having a hydroxyl group include hydroxyanthraquinone compounds and aminohydroxyanthraquinone compounds. Specifically, alizarin, quinizarin, anthralphine, purpurin, 1-hydroxyanthraquinone, 2-amino-3-hydroxyanthraquinone, 1-amino-4-hydroxyanthraquinone and the like are particularly preferably used.

  The content of the electron-accepting substance in the undercoat layer 2a of the present embodiment (including those that are partly in the form of molecules (for example, those that are bound by reacting with other substances)) provides desired characteristics. Although it can be arbitrarily set as long as it is in the range, it is preferably in the range of 0.004 to 16% by mass, preferably in the range of 0.02 to 8% by mass, based on the total solid content in the undercoat layer 2a. More preferred.

  Further, the content of the electron accepting substance in the undercoat layer 2a is preferably in the range of 0.01 to 20 parts by mass with respect to 100 parts by mass of the metal oxide fine particles. More preferably, it is the range of 0.05-10 mass parts with respect to 100 mass parts of metal oxide fine particles. If the content is 0.01 parts by mass or less with respect to 100 parts by mass of the metal oxide fine particles, sufficient acceptor properties that contribute to the improvement of charge accumulation in the undercoat layer cannot be imparted. Further, it is difficult to obtain the suppressing effect. Further, when the content is 20 parts by mass or more with respect to 100 parts by mass of the metal oxide fine particles, aggregation of the metal oxides is likely to occur, so that the metal oxide is good in the undercoat layer 2a when the undercoat layer 2a is formed. A conductive path cannot be formed, which not only tends to deteriorate sustainability such as an increase in residual potential during repeated use, but also tends to cause image quality defects such as black spots.

  The undercoat layer 2a can be formed using an undercoat layer forming coating solution obtained by dispersing each component constituting the undercoat layer 2a in a solvent. In addition, although the compounding ratio (mass ratio) of the electroconductive particle and binder resin in the coating liquid for undercoat layer formation can be arbitrarily set in the range which can obtain desired electrophotographic photoreceptor characteristics, it is 40: 60-95. : 5 is preferable.

  Various additives can be added to the coating solution for forming the undercoat layer in order to improve electrical characteristics, environmental stability, and image quality. As additives, quinone compounds such as chloranil and bromoanil, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (4-naphthyl) -1,3,4-oxadiazole, Oxadiazole compounds such as 2,5-bis (4-diethylaminophenyl) -1,3,4-oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, 5,5 ′ tetra-t-butyl Electron transporting substances such as diphenoquinone compounds such as diphenoquinone, electron transporting pigments such as polycyclic condensation systems and azo systems, zirconium chelate compounds, titanium chelation Things, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, there can be used a known material such as a silane coupling agent.

  The silane coupling agent can be used for the surface treatment of the metal oxide fine particles and the addition to the undercoat layer 2a with the aim of adjusting the resistance and forming an injection barrier from the undercoat layer 2a to the photosensitive layer 4. As an additive for improving the dispersibility, improving the coatability of the photosensitive layer 4 and improving the environmental stability, it can be used by further adding to the coating solution for forming the undercoat layer. Specific examples of the silane coupling agent used here include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ. -Glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β -(Aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane and the like.

  Examples of zirconium chelate compounds include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, Zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Examples of titanium chelate compounds include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt , Titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, polyhydroxy titanium stearate and the like.

  Examples of the aluminum chelate compound include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) and the like.

  These compounds can be used alone or as a mixture or polycondensate of a plurality of compounds.

  As a solvent for adjusting the coating liquid for forming the undercoat layer, any known organic solvent such as alcohol, aromatic, halogenated hydrocarbon, ketone, ketone alcohol, ether, ester, etc. Can be selected. More specifically, for example, methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-acetate Usual organic solvents such as butyl, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene can be used. These solvents can be used alone or in admixture of two or more. When two or more types are mixed and used, any combination can be used as long as the solvent can dissolve the binder resin as a mixed solvent.

  The undercoat layer forming coating solution can be prepared by mixing components such as a binder resin, conductive particles, a silane coupling agent, and an electron accepting substance together with a solvent. At this time, after the binder resin is first dissolved in a solvent, conductive particles, a silane coupling agent, an electron accepting substance, and the like may be added.

  As a method for dispersing the conductive particles and the like in the coating solution for forming the undercoat layer, known methods such as a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker can be used.

  In this embodiment, it is preferable to disperse solids such as conductive particles and an electron-accepting material added as necessary in the undercoat layer 2a as uniformly as possible. It is desirable to disperse by force for a certain time or more.

  As the dispersion condition, for example, in dispersion by a sand mill using glass beads having a diameter of 1 mm, it is preferable to disperse for 0.1 to 100 hours with a filling rate of the glass beads being about 70 to 95% by volume.

  Further, the coating method for forming the coating layer for forming the undercoat layer 2a includes a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, Ordinary methods such as curtain coating can be used.

  In addition, when the electron accepting substance is mixed with the coating liquid for forming the undercoat layer, when the conductive particles and the electron accepting substance are reacted, in the dispersion step of the coating liquid for forming the undercoat layer, The conductive particles and the electron-accepting substance having a group capable of reacting with the conductive particles may be reacted or the coating film may be reacted during drying or curing. Is preferable because it can be uniformly reacted.

  The undercoat layer 2a can be formed by applying a coating solution for forming an undercoat layer onto the conductive substrate 1, and removing the solvent by drying.

The undercoat layer 2a thus formed preferably has a Vickers strength of 35 or more. The volume resistivity of the undercoat layer 2a is preferably in the range of 1 × 10 ⁶ to 1 × 10 ¹³ Ω · cm, and more preferably in the range of 1 × 10 ⁸ to 1 × 10 ¹² Ω · cm. preferable. When the volume resistivity is less than 1 × 10 ⁶ Ω · cm, there is a tendency that a sufficient charging potential cannot be obtained or leakage occurs. Further, if the volume resistivity exceeds 1 × 10 ¹³ Ω · cm, it tends to be difficult to obtain stable potential characteristics during repeated use.

  Furthermore, the undercoat layer 2a can be set to any thickness as long as desired characteristics are obtained, but the thickness is preferably 15 μm or more, and more preferably 15 to 50 μm. When the thickness of the undercoat layer 2a is less than 15 μm, it tends to be difficult to obtain sufficient leakage resistance, and when it exceeds 50 μm, the residual potential tends to increase during long-term use, resulting in abnormal image density. There is a tendency to invite.

  Further, the surface roughness of the undercoat layer 2a is preferably adjusted to ¼n (n is the refractive index of the upper layer) to ½λ of the exposure laser wavelength λ used in order to prevent moire images. . In order to adjust the surface roughness, particles such as resin may be added to the undercoat layer 2a. As such resin particles, silicone resin particles, cross-linked PMMA resin particles, and the like can be used. Also, the undercoat layer 2a can be polished to adjust the surface roughness. As a polishing method, buffing, sand blasting, wet honing, grinding, or the like can be used.

  In the undercoat layer 2a, the method for making the concentration of the silane coupling agent on the photosensitive layer 4 side higher than that on the conductive substrate 1 side is not particularly limited, and may be achieved by any means. It doesn't matter. As such a method, for example, the coating solution for forming the undercoat layer for forming the undercoat layer 2a is applied onto the conductive substrate 1, and then the silane coupling agent is used as a solvent before the coating film is completely dried and cured. The silane coupling agent is immersed in a solution dissolved at a high concentration in the film to allow the silane coupling agent to penetrate into the coating film, and the concentration of the silane coupling agent on the surface side of the undercoat layer 2a (photosensitive layer 4 side) A coating solution for forming an undercoat layer is selected by selecting a combination of components so that the solvent or binder and the silane coupling agent are hardly compatible with each other, and the conductive substrate 1 is prepared using this coating solution. For example, a method of adjusting the silane coupling agent so as to concentrate on the surface side (photosensitive layer 4 side) when the undercoat layer 2a is formed thereon may be mentioned. In addition, when using the method of immersing the coating film in a solution containing a high concentration of the silane coupling agent after forming the coating film, the silane is not contained in the coating film before immersion, that is, in the coating solution for forming the undercoat layer. A coupling agent may not be included. In such a method, the silane coupling agent does not necessarily penetrate into the coating film. For example, a state in which a film containing a high concentration of the silane coupling agent is formed on the coating film surface, or the coating film It may be in a state where a silane coupling agent is attached or bonded to the surface.

  In the undercoat layer 2a in this embodiment, first, the coating amount for forming the undercoat layer is 1% by mass or less based on the total amount of the solid content formed from the coating solution for forming the undercoat layer. Is coated on the conductive substrate 1 to form an undercoat layer, and then the formed undercoat layer is formed on the basis of the total amount of solid content in which the blending amount of the silane coupling agent is formed from the immersion treatment liquid. What was formed by being immersed in the immersion process liquid which is the mass% or more is preferable. When the conductive particles contained in the coating solution for forming the undercoat layer are those that have been surface-treated with a silane coupling agent, the amount of the silane coupling agent in the coating solution for forming the undercoat layer must be conductive. Also included are silane coupling agents attached or bonded to the surface of the particles.

  In the electrophotographic photoreceptor 100 having the undercoat layer 2a of this embodiment, a high concentration content region of the silane coupling agent in which the silane coupling agent is distributed at a high concentration in the vicinity of the interface between the undercoat layer 2a and the photosensitive layer 4. By providing 3a, a hole injection barrier from the undercoat layer 2a to the photosensitive layer 4 is sufficiently formed. On the other hand, by reducing the concentration of the silane coupling agent or not containing the silane coupling agent in the region of the undercoat layer 2a on the side of the conductive substrate 1, holes in the undercoat layer 2a can be used during repeated use over a long period of time. Even if the movement is repeated, the possibility of holes being trapped can be made sufficiently low. Therefore, even when the electrophotographic photoreceptor 100 of the present invention is used repeatedly for a long period of time, it is possible to sufficiently suppress the occurrence of image quality defects such as an increase in residual potential, fogging, and black spots. Furthermore, the electrophotographic photoreceptor 100 can more effectively prevent the occurrence of ghosts. This is presumably because the electron injection property from the photosensitive layer 4 to the undercoat layer 2a could be improved by the high concentration region 3a of the silane coupling agent adjacent to the photosensitive layer 4.

  Next, the undercoat layer 2b and the silane coupling agent-containing layer 3b in the electrophotographic photoreceptor 110 shown in FIG. 2 will be described.

  In the electrophotographic photoreceptor 110, the undercoat layer 2b is a layer containing at least conductive particles. Here, as the conductive particles contained in the undercoat layer 2b, the above-described metal oxide fine particles are preferably used. By including the metal oxide fine particles in the undercoat layer 2b, for example, even when the undercoat layer 2b is thickened, the resistance increase of the undercoat layer 2b can be controlled.

  As the other constituent material of the undercoat layer 2b, the same material as the undercoat layer 2a in the electrophotographic photoreceptor 100 described above is used. However, when the silane coupling agent is included in the undercoat layer 2b, the concentration of the silane coupling agent in the undercoat layer 2b needs to be lower than the concentration of the silane coupling agent in the silane coupling agent-containing layer 3b described later. is there.

  The undercoat layer 2b can be formed in the same manner as the undercoat layer 2a described above using a coating solution for forming the undercoat layer obtained by dispersing each component constituting the undercoat layer 2b in a solvent.

The formed undercoat layer 2b preferably has a Vickers strength of 35 or more. The volume resistivity of the undercoat layer 2a is preferably in the range of 1 × 10 ⁶ to 1 × 10 ¹³ Ω · cm, and more preferably in the range of 1 × 10 ⁸ to 1 × 10 ¹² Ω · cm. preferable. When the volume resistivity is less than 1 × 10 ⁶ Ω · cm, there is a tendency that a sufficient charging potential cannot be obtained or leakage occurs. Further, if the volume resistivity exceeds 1 × 10 ¹³ Ω · cm, it tends to be difficult to obtain stable potential characteristics during repeated use.

  Furthermore, the undercoat layer 2b can be set to any thickness as long as desired characteristics are obtained, but the thickness is preferably 15 μm or more, and more preferably 15 to 50 μm. When the thickness of the undercoat layer 2b is less than 15 μm, it tends to be difficult to obtain sufficient leakage resistance, and when it exceeds 50 μm, the residual potential tends to increase during long-term use, resulting in abnormal image density. There is a tendency to invite.

  The surface roughness of the undercoat layer 2b is preferably adjusted to ¼n (n is the refractive index of the upper layer) to ½λ of the exposure laser wavelength λ used in order to prevent moire images. . In order to adjust the surface roughness, particles such as a resin can be added to the undercoat layer 2b. As such resin particles, silicone resin particles, cross-linked PMMA resin particles, and the like can be used. The undercoat layer 2b can also be polished for adjusting the surface roughness. As a polishing method, buffing, sand blasting, wet honing, grinding, or the like can be used.

  The silane coupling agent-containing layer 3b is a layer containing a silane coupling agent at a higher concentration than the undercoat layer 2b.

  As the silane coupling agent contained in the silane coupling agent-containing layer 3b, any silane coupling agent capable of obtaining desired characteristics can be used, but the above-mentioned silane coupling agent having an amino group is preferably used. .

  The silane coupling agent-containing layer 3b may be composed of only the silane coupling agent, or may be composed of a binder resin, a silane coupling agent, and other additives as necessary. Good.

  Examples of the binder resin used in the silane coupling agent-containing layer 3b include acetal resins such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, and polychlorinated resin. Examples of the polymer resin compound include vinyl resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, and melamine resin. These can be used individually by 1 type or in combination of 2 or more types.

  Moreover, as a constituent material of the silane coupling agent-containing layer 3a, an organometallic compound containing zirconium, titanium, aluminum, manganese, silicon atoms, or the like can be used. These compounds can be used alone or as a mixture or polycondensate of a plurality of compounds. Among these, an organometallic compound containing zirconium or silicon is preferable because it has excellent performance such as low residual potential, little potential change due to environment, and little potential change due to repeated use.

  Examples of silicon compounds include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy)) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltri Methoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl)- Examples include γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, and the like. Particularly preferably used silicon compounds include vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-licidoxypropyltrimethoxysilane, and 2- (3,4-epoxycyclohexyl). ) Ethyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N- Examples include silane coupling agents such as phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane.

  Examples of organic zirconium compounds include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, Zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Examples of organic titanium compounds include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt , Titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, polyhydroxy titanium stearate and the like.

  Examples of organoaluminum compounds include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) and the like.

  The silane coupling agent-containing layer 3b can contain conductive particles. Examples of the conductive particles include those similar to those used for the undercoat layer 2b.

  The silane coupling agent-containing layer 3b may be configured to include conductive particles that have been surface-treated with a silane coupling agent.

  The silane coupling agent-containing layer 3b can be formed using a coating liquid for forming a silane coupling agent-containing layer obtained by dispersing each component constituting the silane coupling agent-containing layer 3b in a solvent.

  The coating solution for forming the undercoat layer for forming the undercoat layer 2b is prepared based on the blending ratio (based on the total solid content) of the silane coupling agent when preparing the coating solution for forming the silane coupling agent-containing layer. The silane coupling agent-containing layer 3b containing the silane coupling agent at a higher concentration than the undercoat layer 2b can be formed by making it larger than the mixing ratio of the silane coupling agent (based on the total solid content). it can. When the conductive particles contained in the coating solution for forming the undercoat layer are those that have been surface-treated with a silane coupling agent, the amount of the silane coupling agent in the coating solution for forming the undercoat layer must be conductive. Also included are silane coupling agents attached or bonded to the surface of the particles. When the coating liquid for forming a silane coupling agent-containing layer contains conductive particles, and the conductive particles are surface-treated with a silane coupling agent, the silane in the coating liquid for forming a silane coupling agent-containing layer The compounding amount of the coupling agent includes a silane coupling agent attached or bonded to the surface of the conductive particles.

  Solvents for adjusting the coating solution for forming a silane coupling agent-containing layer include known organic solvents such as alcohols, aromatics, halogenated hydrocarbons, ketones, ketone alcohols, ethers, esters. It can be arbitrarily selected from the above. More specifically, for example, methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-acetate Usual organic solvents such as butyl, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene can be used. These solvents can be used alone or in admixture of two or more. When two or more types are mixed and used, any combination can be used as long as the solvent can dissolve the binder resin as a mixed solvent.

  The coating liquid for forming a silane coupling agent-containing layer can be prepared by mixing a silane coupling agent and, if necessary, each component such as a binder resin and conductive particles together with a solvent. At this time, after the binder resin is first dissolved in a solvent, a silane coupling agent or conductive particles may be added. Moreover, the coating liquid for forming a silane coupling agent-containing layer may be prepared by mixing conductive particles surface-treated with a silane coupling agent, and, if necessary, each component such as a binder resin together with a solvent. it can.

  As a method of dispersing the silane coupling agent or conductive particles surface-treated with the silane coupling agent in the coating liquid for forming a silane coupling agent-containing layer, a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid A known method such as a mill or a paint shaker can be used.

  In this embodiment, it is preferable to disperse solids such as conductive particles added as necessary in the silane coupling agent-containing layer 3b as uniformly as possible. It is desirable to disperse for a certain period of time.

  As the dispersion condition, for example, in dispersion by a sand mill using glass beads having a diameter of 1 mm, it is preferable to disperse for 0.1 to 100 hours with a filling rate of the glass beads being about 70 to 95% by volume.

  Furthermore, as a coating method of the coating liquid for forming a silane coupling agent-containing layer when forming the silane coupling agent-containing layer 3b, a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method are used. Ordinary methods such as an air knife coating method and a curtain coating method can be used.

  The silane coupling agent-containing layer 3b can be formed by applying a coating liquid for forming a silane coupling agent-containing layer on the undercoat layer 2b and removing the solvent by drying.

  The silane coupling agent-containing layer 3b plays the role of an electrical blocking layer in addition to improving the coating properties of the upper layer. However, when the film thickness is too large, the electrical barrier becomes too strong, resulting in desensitization and repetition. Causes an increase in potential. Therefore, the film thickness of the silane coupling agent-containing layer 3b is preferably 0.1 to 5 μm.

  In the electrophotographic photoreceptor 100 having the undercoat layer 2b and the silane coupling agent-containing layer 3b in the present embodiment, the silane coupling agent is interposed between the undercoat layer 2b and the photosensitive layer 4 more than the undercoat layer 2b. By providing the silane coupling agent-containing layer 3b distributed at a high concentration, a hole injection barrier from the undercoat layer 2b to the photosensitive layer 4 is sufficiently formed. On the other hand, by lowering the concentration of the silane coupling agent or not containing the silane coupling agent in the undercoat layer 2b, even if the movement of holes is repeated in the undercoat layer 2b during repeated use over a long period of time, The possibility of holes being trapped can be made sufficiently low. Therefore, even when the electrophotographic photosensitive member 110 of the present invention is used repeatedly for a long time, it is possible to sufficiently suppress the occurrence of image quality defects such as a rise in residual potential, fogging, and black spots. Furthermore, the electrophotographic photoreceptor 110 can more effectively prevent the occurrence of ghosts. This is presumably because the electron injection property from the photosensitive layer 4 to the undercoat layer 2b could be improved by the silane coupling agent-containing layer 3b provided adjacent to the photosensitive layer 4.

  Next, the photosensitive layer 4 will be described.

  The charge generation layer 5 constituting the photosensitive layer 4 is formed by, for example, vacuum-depositing a charge generation material on the undercoat layer 2a or the silane coupling agent-containing layer 3b, or by applying a dispersion containing the charge generation material to the undercoat layer 2a. Or it forms by apply | coating on the silane coupling agent containing layer 3b. When the charge generation layer 5 is formed by application of a dispersion, the charge generation material is dispersed together with an organic solvent, a binder resin, an additive, and the like, and the obtained dispersion (coating liquid for forming a charge generation layer) is used. it can.

  In the present embodiment, any known charge generating material can be used as the charge generating material. Specifically, for example, phthalocyanine pigments, azo pigments such as squarylium, bisazo, and trisazo, perylene, and dithioketopyrrolopyrrole are included as charge generation materials for infrared light, and condensed as charge generation materials for visible light. Examples thereof include polycyclic pigments, bisazo pigments, perylene, trigonal selenium, and dye-sensitized zinc oxide fine particles. Of these, phthalocyanine pigments and azo pigments are preferably used. By using such a pigment, it is possible to obtain the electrophotographic photoreceptors 100 and 110 with high sensitivity and excellent repeatability.

  Phthalocyanine pigments and azo pigments generally have several crystal types, but any of these crystal types can be used as long as it is a crystal type capable of obtaining electrophotographic characteristics suitable for the purpose. Particularly preferably used charge generating substances include chlorogallium phthalocyanine, dichlorosus phthalocyanine, hydroxygallium phthalocyanine, metal-free phthalocyanine, oxytitanyl phthalocyanine, and chloroindium phthalocyanine.

  The phthalocyanine pigment crystal is obtained by mechanically dry-pulverizing a phthalocyanine pigment produced by a known method with an automatic mortar, planetary mill, vibration mill, CF mill, roller mill, sand mill, kneader, etc. It can manufacture by performing a wet grinding process using a ball mill, a mortar, a sand mill, a kneader, etc.

  Solvents used in the above treatment include aromatics (toluene, chlorobenzene, etc.), amides (dimethylformamide, N-methylpyrrolidone, etc.), aliphatic alcohols (methanol, ethanol, butanol, etc.), aliphatic poly Monohydric alcohols (ethylene glycol, glycerin, polyethylene glycol, etc.), aromatic alcohols (benzyl alcohol, phenethyl alcohol, etc.), esters (acetic ester, butyl acetate, etc.), ketones (acetone, methyl ethyl ketone, etc.), dimethyl sulfoxide, Examples include ethers (diethyl ether, tetrahydrofuran, etc.), a mixture of a plurality of these organic solvents, and a mixture of water and the above organic solvent.

  The solvent to be used is preferably used in the range of 1 to 200 parts by mass, more preferably in the range of 10 to 100 parts by mass with respect to 1 part by mass of the pigment crystal. The treatment temperature is preferably in the range of -20 ° C or higher and lower than the boiling point of the solvent, and preferably in the range of -10 to 60 ° C. In addition, grinding aids such as sodium chloride and sodium nitrate can be used during grinding. The grinding aid is preferably used 0.5 to 20 times, more preferably 1 to 10 times the mass of the pigment.

  The phthalocyanine pigment crystal can also be controlled by a process combining acid pasting or acid pasting and dry pulverization or wet pulverization as described above. As an acid used for acid pasting, sulfuric acid is preferable, and one having a concentration of 70 to 100%, preferably 95 to 100% is used, and a dissolution temperature is in a range of -20 to 100 ° C, preferably -10 to 60 ° C. Set to The amount of sulfuric acid is set in the range of 1 to 100 times, preferably 3 to 50 times the mass of the phthalocyanine pigment crystals. As a solvent to be precipitated, water or a mixed solvent of water and an organic solvent is used in an arbitrary amount. The temperature for precipitation is not particularly limited, but it is preferably cooled with ice or the like in order to prevent heat generation.

  The binder resin can be selected from a wide range of insulating resins, and can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, and polysilane. Preferred binder resins include polyvinyl acetal resin, polyarylate resin (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin Insulating resins such as polyacrylamide resin, polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinyl pyrrolidone resin can be mentioned, but are not limited thereto. These binder resins can be used singly or in combination of two or more. Of these, polyvinyl acetal resin is particularly preferably used.

  The blending ratio (mass ratio) of the charge generating material and the binder resin in the charge generating layer forming coating solution is preferably in the range of 10: 1 to 1:10.

  As the organic solvent contained in the coating solution for forming the charge generation layer, any known organic solvent such as alcohol, aromatic, halogenated hydrocarbon, ketone, ketone alcohol, ether, ester, etc. You can choose. For example, methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, Usual organic solvents such as methylene chloride, chloroform, chlorobenzene, and toluene can be used. These solvents may be used alone or in combination of two or more. In the case of using a mixture of solvents, any solvent can be used as long as it can dissolve the binder resin as the mixed solvent.

  As a method for dispersing the charge generation material, the binder resin, and the organic solvent, a method using a roll mill, a ball mill, a vibration ball mill, an attritor, a sand mill, a colloid mill, a paint shaker, or the like can be used. Further, the particle size of the charge generating material is 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less during the dispersion, thereby improving the sensitivity and stability of the photoreceptor. Can be improved.

  In addition, the charge generation material can be subjected to a surface treatment for improving the stability of electrical characteristics and preventing image quality defects. As the surface treatment agent, a silane coupling agent, a zirconium chelate compound, a titanium chelate compound, an aluminum chelate compound and the like can be used, but the surface treatment agent is not limited thereto. As these specific examples, the additive of the undercoat layer forming coating liquid and the organometallic compound used for the silane coupling agent-containing layer 3b are similarly used.

  In addition, various additives can be added to the charge generation layer forming coating solution in order to improve electrical characteristics and image quality. As a specific example of the additive, the additive used in the coating solution for forming the undercoat layer can be used in the same manner.

  The coating solution for forming the charge generation layer can be applied onto the undercoat layer 2a or the silane coupling agent-containing layer 3b by blade coating, wire bar coating, spray coating, dip coating, bead coating, air Usual methods such as a knife coating method and a curtain coating method can be used.

  The film thickness of the charge generation layer 5 is preferably in the range of 0.01 to 3 μm, and more preferably in the range of 0.1 to 1 μm.

  The charge transport layer 6 includes a charge transport material and a binder resin.

  The charge transport material is not particularly limited, and any known material can be used. Specific examples of the charge transport material include the following.

  That is, oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5-triphenyl-pyrazoline, 1- [pyridyl- (2)] Pyrazoline derivatives such as -3- (p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline, triphenylamine, tri (p-methyl) phenylamine, N, N′-bis (3,4-dimethylphenyl) ) Aromatic tertiary amino compounds such as biphenyl-4-amine, dibenzylaniline, 9,9-dimethyl-N, N′-di (p-tolyl) fluorenon-2-amine, N, N′-diphenyl- Aromatic tertiary diamino compounds such as N, N′-bis (3-methylphenyl)-[1,1-biphenyl] -4,4′-diamine, 3- (4′-dimethyl) 1,2,4-triazine derivatives such as aminophenyl) -5,6-di- (4′-methoxyphenyl) -1,2,4-triazine, 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, 4- Hydrazone derivatives such as diphenylaminobenzaldehyde-1,1-diphenylhydrazone, [p- (diethylamino) phenyl] (1-naphthyl) phenylhydrazone, quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline, 6-hydroxy-2 Benzofuran derivatives such as 1,3-di (p-methoxyphenyl) -benzofuran, α-stilbene derivatives such as p- (2,2-diphenylvinyl) -N, N′-diphenylaniline, enamine derivatives, N-ethylcarbazole, etc. Carbazole derivatives of poly-N-vinylcarbazole Hole transport materials such as bisphenol derivatives, quinone compounds such as chloranil, bromoanil, anthraquinone, tetracyanoquinodimethane compounds, 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitro-9- Fluorenone compounds such as fluorenone, 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole and 2,5-bis (4-naphthyl) -1,3 Oxadiazole compounds such as 4-oxadiazole and 2,5-bis (4-diethylaminophenyl) 1,3,4 oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, 5,5′- Polymerization having a main chain or a side chain with an electron transport material such as a diphenoquinone compound such as tetra-t-butyldiphenoquinone, and a group consisting of the compounds shown above. Examples include the body. These charge transport materials can be used alone or in combination of two or more.

  Moreover, as a charge transport substance, the compound shown by the following general formula (a-1), (a-2) or (a-3) from a mobility viewpoint is preferable.

In the formula ^{(a-1), R 34} is a methyl group, k10 represents an integer of 0 to 2. Ar ⁶ and Ar ⁷ are each a substituted or unsubstituted aryl group, —C ₆ H ₄ —C (R ³⁸ ) ═C (R ³⁹ ) (R ⁴⁰ ), or —C ₆ H ₄ —CH═CH—. CH = C (Ar) ₂ represents a substituted amino substituted with a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkyl group having 1 to 3 carbon atoms Groups. R ³⁸ , R ³⁹ and R ⁴⁰ represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and Ar represents a substituted or unsubstituted aryl group.

In the above formula (a-2), R ³⁵ and R ³⁵ ′ each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms, R ³⁶ , R ³⁶ ′. , R ³⁷ and R ³⁷ ′ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an amino group substituted with an alkyl group having 1 to 2 carbon atoms, A substituted or unsubstituted aryl group, —C (R ³⁸ ) ═C (R ³⁹ ) (R ⁴⁰ ), or —CH═CH—CH═C (Ar ′) ₂ , R ³⁸ , R ³⁹ and R ^40; Each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and Ar ′ represents a substituted or unsubstituted aryl group. M4 and m5 each independently represents an integer of 0 to 2.

Here, in the formula (a-3), R ⁴¹ represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a substituted or unsubstituted aryl group, or —CH═CH. -CH = C (Ar ") ₂ is shown. Ar ″ represents a substituted or unsubstituted aryl group. R ⁴² , R ⁴² ′, R ⁴³ , and R ⁴³ ′ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkyl having 1 to 2 carbon atoms. An amino group substituted with a group, or a substituted or unsubstituted aryl group is shown.

  As the binder resin used for the charge transport layer 6, any known resin can be used, but an electrically insulating film-forming resin is preferable. For example, polycarbonate resin, polyester resin, polyarylate resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, acrylonitrile-styrene copolymer, acrylonitrile-butadiene copolymer, polyvinyl acetate resin, styrene -Butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene -Alkyd resin, poly-N-carbazole, polyvinyl butyral, polyvinyl formal, polysulfone, casein, gelatin, polyvinyl alcohol, ethyl cellulose, pheno Resin, polyamide, polyacrylamide, carboxymethylcellulose, vinylidene chloride polymer wax, insulating resin such as polyurethane, polyvinylcarbazole, polyvinylanthracene, polyvinylpyrene, polysilane, JP-A-8-176293 and JP-A-8-208820 Examples thereof include polymer charge transport materials such as polyester polymer charge transport materials disclosed in the publication. These binder resins can be used alone or in combination of two or more. Among these, polycarbonate resin, polyester resin, methacrylic resin, and acrylic resin are particularly preferably used from the viewpoint of compatibility with the charge transport material, solubility in a solvent, and strength.

  The blending ratio (mass ratio) between the charge transport material and the binder resin is preferably set with attention to a decrease in electrical characteristics and a decrease in film strength, for example, preferably 10: 1 to 1: 5.

  In addition, a polymer charge transport material can be used alone for forming the charge transport layer 6. As the polymer charge transporting material, known materials having charge transporting properties such as poly-N-vinylcarbazole and polysilane can be used. In particular, polyester polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 have a high charge transporting property and are particularly preferable. The polymer charge transport material alone can be used as the charge transport layer, but may be formed by mixing with the binder resin described above. Also in this case, the blending ratio (mass ratio) of the charge transport material and the binder resin is preferably 10: 1 to 1: 5.

  The charge transport layer 6 is formed by applying a charge transport layer forming coating solution in which a charge transport material, a binder resin, and other additives as required are dissolved in an appropriate solvent, onto the charge generation layer 5 and drying. Can be formed.

  Examples of the solvent used in the coating solution for forming the charge transport layer include aromatic hydrocarbon solvents such as toluene and chlorobenzene, aliphatic alcohol solvents such as methanol, ethanol and n-butanol, acetone, cyclohexanone and 2-butanone. Ketone solvents such as, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform and ethylene chloride, cyclic or linear ether solvents such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether, and mixed solvents thereof Is mentioned.

  Methods for dispersing charge transport materials, binder resins and solvents include roll mills, ball mills, vibrating ball mills, attritors, sand mills, high-pressure homogenizers, ultrasonic dispersers, colloid mills, colliding medialess dispersers, and penetrating medialess. A method such as a disperser can be used.

  Further, a slight amount of a leveling agent such as silicone oil for improving the smoothness of the coating film can be added to the coating solution for forming the charge transport layer. Further, it is also effective to add a small amount of a dispersion aid in order to improve the dispersion stability of the coating liquid and to prevent aggregation during the formation of the coating film. Examples of the dispersion aid include a fluorine-based surfactant, a fluorine-based polymer, a silicone-based polymer, and a silicone oil.

  The coating solution for forming the charge transport layer is preferably prepared by mixing while maintaining the temperature of the solution containing the solvent, the binder resin and the charge transport material at 0 ° C. to 50 ° C. As a method of controlling the liquid temperature within such a temperature range, for example, cooling with water, cooling with wind, cooling with refrigerant, adjusting the room temperature for producing the coating liquid, warming with warm water, warming with hot air, warming with a heater, Methods such as making a coating liquid manufacturing facility with a material that does not easily generate heat, creating a coating liquid manufacturing facility with a material that easily dissipates heat, and making a coating liquid manufacturing facility with a material that easily stores heat can be used.

  Methods for applying the charge transport layer forming coating solution onto the charge generation layer 5 include dip coating, push-up coating, spray coating, roll coater coating, wire bar coating, gravure coater coating, and bead coating. A method such as a curtain coating method, a blade coating method, or an air knife coating method can be used.

  The film thickness of the charge transport layer 6 is preferably in the range of 5 to 50 μm, and more preferably in the range of 10 to 45 μm.

  In the electrophotographic photosensitive member of this embodiment, when the charge transport layer 6 is the outermost layer of the electrophotographic photosensitive members 100 and 110 (the layer disposed on the side farthest from the conductive substrate 1 of the photosensitive layer), That is, when the photoconductor does not include a protective layer 7 described later, the charge transport layer 6 preferably contains lubricating particles. By imparting lubricity to the outermost layer of the photoconductor in this manner, the photoconductor can be made less likely to be worn or scratched, and the cleaning property of the developer attached to the surface of the photoconductor can be improved. be able to. Examples of the lubricating particles include silica particles, alumina particles, fluorine resin particles such as polytetrafluoroethylene (PTFE), and silicone resin particles. These lubricating particles can be used in combination of two or more. In particular, fluorine resin particles are preferably used.

  Examples of the fluorine resin particles include tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluoropropylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluorodiethylene chloride resin and copolymers thereof. Can be mentioned. These can be used by appropriately selecting one kind or two or more kinds. Of these, tetrafluoroethylene resin and vinylidene fluoride resin are particularly preferable.

  The primary particle size of the fluororesin particles is preferably in the range of 0.05 to 1 μm, and more preferably in the range of 0.1 to 0.5 μm. When the primary particle size is less than 0.05 μm, aggregation tends to proceed at the time of dispersion or after dispersion. On the other hand, if it exceeds 1 μm, image quality defects are likely to occur.

  The content of the fluorine-based resin particles in the charge transport layer 6 is preferably in the range of 0.1 to 40% by mass, and in the range of 1 to 30% by mass with respect to the total amount of the constituent components of the charge transport layer 6. More preferably. If the content of the fluorine-based resin particles is less than 0.1% by mass, it is difficult to sufficiently obtain a modification effect due to the dispersion of the fluorine-based resin particles. On the other hand, if the content exceeds 40% by mass, the light transmission property decreases, and The residual potential is likely to increase due to repeated use.

  The charge transport layer 6 containing fluorine resin particles can be formed using the above-described coating liquid for forming a charge transport layer.

  As a method of dispersing the fluorine resin particles in the coating liquid for forming the charge transport layer, a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a high-pressure homogenizer, an ultrasonic disperser, a colloid mill, a collision-type medialess disperser, A method such as a through-type medialess disperser can be used.

  Further, when preparing a coating solution for forming a charge transport layer containing fluorine-based resin particles, a mixture of fluorine-based resin particles and the above dispersion aid previously mixed and stirred in a small amount of a dispersion solvent is charged. It is also an effective preparation means to mix with a mixed liquid of a transport substance, a binder resin and a solvent, stir and then further disperse by the above method.

  In the electrophotographic photosensitive member of the present embodiment, an anti-oxidant, light, or the like is contained in the photosensitive layer 4 for the purpose of preventing deterioration of the electrophotographic photosensitive member due to ozone or oxidizing gas generated in the copying machine, light, or heat. Additives such as stabilizers and heat stabilizers can be added.

  Examples of the antioxidant include hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and derivatives thereof, organic sulfur compounds, and organic phosphorus compounds.

  More specifically, examples of the phenol-based antioxidant include 2,6-di-t-butyl-4-methylphenol, styrenated phenol, and n-octadecyl-3- (3 ′, 5′-di). -T-butyl 4'-hydroxyphenyl) -propionate, 2,2'-methylene-bis- (4-methyl-6-t-butylphenol), 2-t-butyl-6- (3'-t-butyl- 5′-methyl-2′-hydroxybenzyl) -4-methylphenyl-acrylate, 4,4′-butylidene-bis- (3-methyl-6-tert-butylphenol), 4,4′-thio-bis- ( 3-methyl-6-tert-butylphenol), 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, tetrakis- [methylene-3- (3 , 5'-di-t-butyl-4'-hydroxy-phenyl) propionate] -methane, 3,9-bis [2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyl Oxy] -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro- [5,5] -undecane and the like.

  Examples of hindered amine compounds include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [ 2- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy ] -2,2,6,6-tetramethylpiperidine, 8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4 -Dione, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethyl succinate Piperidine polycondensate, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diimyl} {(2,2,6,6-tetra Methyl-4-piperidyl) imino} hexamethylene {(2,3,6,6-tetramethyl-4-piperidyl) imino}], 2- (3,5-di-t-butyl-4-hydroxybenzyl) 2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl -N- (1,2,2,6,6-pentamethyl-4piperidyl) amino] -6-chloro-1,3,5-triazine condensate and the like.

  Examples of the organic sulfur antioxidant include dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, pentaerythritol. -Tetrakis- (β-lauryl-thiopropionate), ditridecyl-3,3′-thiodipropionate, 2-mercaptobenzimidazole and the like.

  Examples of the organic phosphorus-based antioxidant include trisnonylphenyl phosphite, triphenyl phosfte, tris (2,4-di-t-butylphenyl) -phosfte, and the like.

  Organic sulfur-based and organic phosphorus-based antioxidants are said to be secondary antioxidants, and a synergistic effect can be obtained by using them together with primary antioxidants such as phenol-based or amine-based antioxidants.

  Examples of the light stabilizer include derivatives such as benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine.

  More specifically, examples of the benzotriazole-based light stabilizer include 2- (2′-hydroxy-5′methylphenyl) -benzotriazole and 2- [2′-hydroxy-3 ′-(3 ″). , 4 ″, 5 ″, 6 ″ -tetra-hydrophthalimido-methyl) -5′-methylphenyl] -benzotriazole, 2- (2′-hydroxy-3′-tert-butyl-5′-methyl) Phenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5' -T-butylphenyl) -benzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl) -benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-a Butylphenyl) - benzotriazole.

  Examples of light stabilizers other than the above compounds include 2,4-di-t-butylphenyl-3 ′, 5′-di-t-butyl-4′-hydroxybenzoate, nickel dibutyl-dithiocarbamate, and the like. It is done.

  The photosensitive layer 4 can contain at least one electron accepting substance for the purpose of improving sensitivity, reducing residual potential, reducing fatigue during repeated use, and the like.

Examples of the electron accepting substance include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-dinitrobenzene. , Chloranil, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, phthalic acid and the like. Of these, fluorenone-based, quinone-based, and benzene derivatives having electron-withdrawing substituents such as Cl, CN, NO ₂ are particularly preferable.

  The protective layer 7 prevents chemical changes of the charge transport layer 6 during charging in the electrophotographic photoreceptors 100 and 110 having a laminated structure, improves the mechanical strength of the photosensitive layer 4, and wears or scratches the surface layer. It is provided to further improve the resistance to the above.

  Examples of the protective layer 7 include a cured resin film including a curable resin and a charge transporting compound, and a film formed from a binder resin including a conductive material. In the present embodiment, a cured resin film including a curable resin and a charge transporting compound is preferable.

  Any known resin can be used as the curable resin, but those capable of forming a crosslinked structure are preferred from the viewpoints of film strength, photoreceptor electrical properties, image quality maintenance, and the like. Examples of such resins include phenol resins, urethane resins, melamine resins, diallyl phthalate resins, siloxane resins, and the like.

  The curable resin can be used without particular limitation as long as it is a known resin, but is preferably one that can form a crosslinked structure from the viewpoint of film strength, electrical characteristics of the photoreceptor and image quality maintenance. Examples of such resins include phenol resins, urethane resins, melamine resins, diallyl phthalate resins, siloxane resins, and the like.

  The charge transporting compound used for the protective layer 7 has a reactive functional group and is preferably compatible with the curable resin used, and further forms a chemical bond with the curable resin used. Those are more preferred. As the charge transport compound having a reactive functional group, a compound represented by the following general formula (I), (II), (III), (IV), (V) or (VI) is preferable.

F [-D-Si (R ¹ ) _(3-a) Q _a ] _b (I)
[In Formula (I), F represents an organic group derived from a compound having a hole transporting ability, D represents a divalent group having flexibility, and R ¹ represents a hydrogen atom, a substituted or unsubstituted group. An alkyl group or a substituted or unsubstituted aryl group, Q represents a hydrolyzable group, a represents an integer of 1 to 3, and b represents an integer of 1 to 4; ]

F [— (X ¹ ) _n1 R ² —Z ¹ H] _m1 (II)
[In Formula (II), F represents an organic group derived from a compound having a hole transporting ability, R ² represents an alkylene group, Z ¹ represents an oxygen atom, a sulfur atom, NH or COO, and X ¹ Represents an oxygen atom or a sulfur atom, m1 represents an integer of 1 to 4, and n1 represents 0 or 1. ]

^{_{F [- (X 2) n2}} - (R 3) n3 - (Z 2) n4 G] n5 (III)
[In Formula (III), F represents an organic group derived from a compound having a hole transporting ability, X ² represents an oxygen atom or a sulfur atom, R ³ represents an alkylene group, Z ² represents an oxygen atom, S represents a sulfur atom, NH or COO, G represents an epoxy group, n2, n3 and n4 each independently represents 0 or 1, and n5 represents an integer of 1 to 4. ]

［式（ＩＶ）中、Ｆは正孔輸送性を有する化合物から誘導される有機基を示し、Ｔは２価の基を示し、Ｙは酸素原子又は硫黄原子を示し、Ｒ^４、Ｒ^５及びＲ^６はそれぞれ独立に水素原子又は１価の有機基を示し、Ｒ^７は１価の有機基を示し、ｍ２は０又は１を示し、ｎ６は１〜４の整数を示す。但し、Ｒ^６とＲ^７は互いに結合してＹをヘテロ原子とする複素環を形成してもよい。］

[In Formula (IV), F represents an organic group derived from a compound having a hole transporting property, T represents a divalent group, Y represents an oxygen atom or a sulfur atom, R ⁴ , R ⁵ and R ⁶ independently represents a hydrogen atom or a monovalent organic group, R ⁷ represents a monovalent organic group, m 2 represents 0 or 1, and n 6 represents an integer of 1 to 4. However, R ⁶ and R ⁷ may combine with each other to form a heterocycle having Y as a heteroatom. ]

［式（Ｖ）中、Ｆは正孔輸送性を有する化合物から誘導される有機基を示し、Ｔは２価の基を示し、Ｒ^８は１価の有機基を示し、ｍ３は０又は１を示し、ｎ７は１〜４の整数を示す。］

[In Formula (V), F represents an organic group derived from a compound having a hole transporting property, T represents a divalent group, R ⁸ represents a monovalent organic group, and m3 represents 0 or 1 N7 represents an integer of 1 to 4. ]

［式（ＶＩ）中、Ｆは正孔輸送性を有する化合物から誘導される有機基を示し、Ｒ^９は１価の有機基を示し、Ｌはアルキレン基を示し、ｎ８は１〜４の整数を示す。］

[In Formula (VI), F represents an organic group derived from a compound having a hole transporting property, R ⁹ represents a monovalent organic group, L represents an alkylene group, and n8 represents an integer of 1 to 4. Indicates. ]

  In the above general formulas (I) to (VI), F is a unit having photoelectric characteristics, specifically, photocarrier transport characteristics, and a structure conventionally known as a charge transport material can be used as it is. . Specifically, compound skeletons having hole transport properties such as triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, hydrazone compounds, and quinones A compound skeleton having an electron transporting property such as a compound, a fluorenone compound, a xanthone compound, a benzophenone compound, a cyanovinyl compound, or an ethylene compound can be used.

In the general formula (I), —Si (R ¹ ) _(3-a) Q _a is a substituted silicon group having a hydrolyzable group, and the substituted silicon undergoes a crosslinking reaction with the Si group. A three-dimensional Si—O—Si bond is formed. That is, this substituted silicon group plays a role of forming a so-called inorganic glassy network in the protective layer 7.

In the above general formula (I), D represents a divalent group having flexibility. Specifically, it is directly bonded to an F site for imparting photoelectric characteristics and a three-dimensional inorganic glassy network. An organic group that plays a role in linking to a substituted silicon group that is tied in, and gives moderate flexibility to an inorganic glassy network that is hard but brittle, and improves the toughness of the film. To express. Specific examples _{D, -C n H 2n -,} - C n H (2n-2) -, - C n H (2n-4) - 2 divalent hydrocarbon group (here represented, n is represents an integer of _{1~15), - COO -, -} S -, - O -, - CH 2 -C 6 H 4 -, - N = CH -, - (C 6 H 4) - (C 6 H 4 )-And a characteristic group arbitrarily combining these, and those obtained by substituting structural atoms of these characteristic groups with other substituents.

  In the general formula (I), b is preferably 2 or more. When b is 2 or more, the photofunctional organosilicon compound represented by the general formula (I) contains two or more Si atoms, and it becomes easy to form an inorganic glassy network, and mechanical strength is increased. Will improve.

  The F in the compounds represented by the general formulas (I) to (VI) is preferably a group represented by the following general formula (VII). The group represented by the following general formula (VII) is a group having a hole transporting ability, and it is particularly preferable that the protective layer 7 contains this from the viewpoint of improving the photoelectric characteristics and mechanical characteristics of the protective layer 7.

［式（ＶＩＩ）中、Ａｒ^１、Ａｒ^２、Ａｒ^３及びＡｒ^４はそれぞれ独立に置換又は未置換のアリール基を示し、Ａｒ^５は置換若しくは未置換のアリール基又はアリーレン基を示し、且つＡｒ^１〜Ａｒ^５のうち１〜４個は、上記一般式（Ｉ）で表わされる化合物における下記一般式（ＶＩＩＩ）で示される部位、上記一般式（ＩＩ）で表わされる化合物における下記一般式（ＩＸ）で示される部位、上記一般式（ＩＩＩ）で表わされる化合物における下記一般式（Ｘ）で示される部位、上記一般式（ＩＶ）で表わされる化合物における下記一般式（ＸＩ）で示される部位、上記一般式（Ｖ）で表わされる化合物における下記一般式（ＸＩＩ）で示される部位、又は、上記一般式（ＶＩ）で表わされる化合物における下記一般式（ＸＩＩＩ）で示される部位、と結合するための結合手を有し、ｋは０又は１を示す。］

[In formula (VII), Ar ¹ , Ar ² , Ar ³ and Ar ⁴ each independently represent a substituted or unsubstituted aryl group, Ar ⁵ represents a substituted or unsubstituted aryl group or an arylene group, and Ar ^{1 to} 4 of ^{1 to} Ar ⁵ are a moiety represented by the following general formula (VIII) in the compound represented by the above general formula (I), a general formula (IX) in the compound represented by the above general formula (II), ), A site represented by the following general formula (X) in the compound represented by the above general formula (III), a site represented by the following general formula (XI) in the compound represented by the above general formula (IV), The moiety represented by the following general formula (XII) in the compound represented by the general formula (V), or the following general formula (XIII) in the compound represented by the general formula (VI) ), And k represents 0 or 1. ]

^{_{-D-Si (R 1) (}} 3-a) Q a (VIII)
^{_{- (X 1) n1 R 1}} -Z 1 H (IX)
^{_{- (X 2) n2 - (}} R 2) n3 - (Z 2) n4 G (X)

In addition, as the substituted or unsubstituted aryl group represented by Ar ^{1 to} Ar ⁴ in the general formula (VII), specifically, aryl groups represented by the following general formulas (1) to (7) are preferable. .

The formula (1) ~ ^{(7), R 11} is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, alkoxy group having 1 to 4 carbon atoms, phenyl which is substituted by them A group or an unsubstituted phenyl group, or an aralkyl group having 7 to 10 carbon atoms, wherein R ^{12 to} R ¹⁴ are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a carbon number, respectively. 1 to 4 alkoxy groups, phenyl or unsubstituted phenyl groups substituted therewith, aralkyl groups having 7 to 10 carbon atoms or halogen atoms, Ar represents a substituted or unsubstituted arylene group, and X represents the above One of the structures represented by the general formulas (VIII) to (XIII) is shown, c and s each represent 0 or 1, and t represents an integer of 1 to 3.

  Moreover, as Ar in the aryl group represented by the above formula (7), an arylene group represented by the following formula (8) or (9) is preferable.

In the above formulas (8) and (9), R ¹⁵ and R ¹⁶ are each substituted with a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms. A phenyl group, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, or a halogen atom, and t represents an integer of 1 to 3.

  Moreover, as Z 'in the aryl group represented by the above formula (7), divalent groups represented by the following formulas (10) to (17) are preferable.

In the above formulas (10) to (17), R ¹⁷ and R ¹⁸ are each substituted with a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms. A phenyl group, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, or a halogen atom, W represents a divalent group, q and r each represent an integer of 1 to 10, and t Represents an integer of 1 to 3, respectively.

  In the above formulas (16) to (17), W represents a divalent group represented by the following formulas (18) to (26). In formula (25), u represents an integer of 0 to 3.

In addition, the specific structure of Ar ⁵ in the general formula (VII) is as follows. When k = 0, the structure of c = 1 in the specific structure of Ar ^{1 to} Ar ⁴ and when Ar = 1, the Ar 5 ^The structure of c = 0 in the specific structure of ^{1 to} Ar ⁴ is given.

Specific examples of the compound represented by the general formula (I) include the following compounds (I-1) to (I-61). The following compounds (I-1) to (I-61) are prepared by combining Ar ^{1 to} Ar ⁵ and k of the compound represented by the general formula (VII) as shown in the following table, and an alkoxysilyl group. (S) is the specific one shown in the table below.

  Specific examples of the compound represented by the general formula (II) include the following compounds (II-1) to (II-37). In addition, in the following table | surface, although the bond is described, the thing in which the substituent is not described shows a methyl group.

  Moreover, as a compound shown by the said general formula (III), the following compounds (III-1)-(III-47) are mentioned more specifically. In the following table, Me or a bond is described but a substituent is not described, a methyl group, Et represents an ethyl group.

  Specific examples of the compound represented by the general formula (IV) include the following compounds (IV-1) to (IV-40). In the following table, Me or a bond is described but a substituent is not described, a methyl group, Et represents an ethyl group.

  Specific examples of the compound represented by the general formula (V) include the following compounds (V-1) to (V-55). In the following table, Me or a bond is described but a substituent is not described indicates a methyl group.

In the compound represented by the general formula (VI), in the general formula (VI), R ⁹ is preferably a monovalent organic group having 1 to 18 carbon atoms, and may be substituted with a halogen atom. It is more preferably a monovalent hydrocarbon group having 1 to 18 carbon atoms, or a group represented by — (CH ₂ ) _f —O—R ²⁴ , and an alkyl group having 1 to 4 carbon atoms, or — A group represented by (CH ₂ ) _f —O—R ²⁴ is more preferable, and a methyl group is particularly preferable. R ²⁴ represents a hydrocarbon group having 1 to 6 carbon atoms and may form a ring, but is preferably an aliphatic hydrocarbon group such as a methyl group, an ethyl group, a propyl group, or a butyl group, f shows the integer of 1-12, and it is preferable that it is an integer of 1-4. Moreover, in the said general formula (VI), it is preferable that L is a C1-C18 alkylene group which may be branched, and it is more preferable that it is a methylene group. In the general formula (VI), when there are a plurality of R ⁹ or L, each may be the same or different.

  Specific examples of the compound represented by the general formula (VI) include the following compounds (VI-1) to (VI-59). In addition, the compound shown by the said general formula (VI) is not limited at all by these. Moreover, in the following table | surfaces, although the bond is described but the substituent is not described, it shows a methyl group.

  The charge transporting compounds represented by the general formulas (I) to (VI) may be used alone or in combination of two or more.

  Further, the protective layer 7 has a charge transporting compound represented by the above general formula (I) and 2 represented by the following general formula (XIV) for the purpose of further improving the mechanical strength of the cured film. It is also preferable to use a compound having two or more silicon atoms.

B (—Si (R ⁵⁰ ) _(3-a) Q _a ) _d (XIV)
[In formula (XIV), B represents a divalent or higher organic group, R ⁵⁰ represents a hydrogen atom, an alkyl group, or a substituted or unsubstituted aryl group, Q represents a hydrolyzable group, and a represents 1 to 1 3 represents an integer, and d represents an integer of 2 or more. ]

Although it does not specifically limit as a compound represented by the said general formula (XIV), For example, the compound represented by the following compounds (XIV-1)-(XIV-5) can be mentioned as a preferable thing. In formulas (XIV-1) to (XIV-5), T ¹ and T ² each independently represent a divalent or trivalent hydrocarbon group which may be branched. ^Further, A is a substituted silicon group having a hydrolyzable represented by _{-SiR 50 (3-a) Q} a. h, i, and j each independently represent an integer of 1 to 3. The compounds represented by formulas (XIV-1) to (XIV-5) are selected so that the number of A in the molecule is 2 or more.

  Preferred examples of the compound represented by the general formula (XIV) are shown below. In the following table, Me represents a methyl group, Et represents an ethyl group, and Pr represents a propyl group.

  In addition to the compound represented by the general formula (I), another compound capable of crosslinking reaction may be used in combination. As such a compound, various silane coupling agents, commercially available silicone hard coat agents, and the like can be used.

  Examples of the silane coupling agent include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropyl. Trimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, tetramethoxysilane, methyltrimethoxy Examples thereof include silane and dimethyldimethoxysilane.

  As a commercially available hard coat agent, KP-85, CR-39, X-12-2208, X-40-9740, X-41-1007, KNS-5300, X-40-2239 (above, manufactured by Shin-Etsu Silicone Co., Ltd.) ), AY42-440, AY42-441, AY49-208 (manufactured by Toray Dow Corning), and the like.

  Further, a fluorine atom-containing compound can be added to the protective layer 7 for the purpose of imparting surface lubricity. By improving the surface lubricity, the coefficient of friction with the cleaning member decreases, and the wear resistance can be improved. In addition, it has an effect of preventing adhesion of discharge products, developer, paper dust, and the like to the surface of the electrophotographic photosensitive member, which is useful for improving the life of the electrophotographic photosensitive members 100 and 110.

  As the fluorine-containing compound, a fluorine atom-containing polymer such as polytetrafluoroethylene can be added as it is, or fine particles of these polymers can be added. Examples of the polymer fine particles include fluorine resin particles that are preferably contained when the charge transport layer 6 is the outermost layer.

  In the case where the protective layer 7 is a cured film formed of the compound represented by the general formula (I), a fluorine-containing compound that can react with an alkoxysilane is added to form a part of the crosslinked film. Is desirable.

  Specific examples of such a fluorine atom-containing compound include (tridecafluoro-1,1,2,2-tetrahydrooctyl) triethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, 3- (Heptafluoroisopropoxy) propyltriethoxysilane, 1H, 1H, 2H, 2H-perfluoroalkyltriethoxysilane, 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane, 1H, 1H, 2H, 2H-per And fluorooctyltriethoxysilane.

  The amount of the fluorine-containing compound added is preferably 20% by mass or less based on the total solid content in the protective layer 7. When the addition amount exceeds 20% by mass, there may be a problem in the film formability of the crosslinked cured film.

  The protective layer 7 has sufficient oxidation resistance, but an antioxidant may be added for the purpose of imparting stronger oxidation resistance. Antioxidants are preferably hindered phenols or hindered amines, organic sulfur antioxidants, phosphite antioxidants, dithiocarbamate antioxidants, thiourea antioxidants, benzimidazole antioxidants. You may use well-known antioxidants, such as. As addition amount of antioxidant, 15 mass% or less is preferable on the basis of the total amount of solid content in the protective layer 7, and 10 mass% or less is further more preferable.

  Examples of the hindered phenol antioxidant include 2,6-di-t-butyl-4-methylphenol, 2,5-di-t-butylhydroquinone, N, N′-hexamethylene bis (3,5-di). -T-butyl-4-hydroxyhydrocinnamide, 3,5-di-t-butyl-4-hydroxy-benzylphosphonate-diethyl ester, 2,4-bis [(octylthio) methyl] -o-cresol, 2,6-di-t-butyl-4-ethylphenol, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-butylphenol) 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 2,5-di-t-amylhydroquinone, 2-t-butyl-6- (3-butyl-2- Dorokishi-5-methylbenzyl) -4-methylphenyl acrylate, 4,4'-butylidene bis (3-methyl -6-t-butylphenol) and the like.

  It is also possible to add other additives used for forming a known coating film to the protective layer 7, and use known materials such as a leveling agent, an ultraviolet absorber, a light stabilizer, and a surfactant. it can.

  The protective layer 7 can be formed by applying a protective layer-forming coating solution containing the above-described various materials and various additives onto the photosensitive layer 4 and subjecting it to a heat treatment. Thereby, the compounds represented by the above general formulas (I) to (VI) undergo a cross-linking curing reaction three-dimensionally, and a firm cured film is formed. The temperature of the heat treatment is not particularly limited as long as it does not affect the underlying photosensitive layer 4, but is preferably room temperature to 200 ° C, more preferably 100 to 160 ° C.

  In the formation of the protective layer 7, the crosslinking curing reaction may be performed without a catalyst or an appropriate catalyst may be used. Catalysts include acid catalysts such as hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid and trifluoroacetic acid, bases such as ammonia and triethylamine, organotin compounds such as dibutyltin diacetate, dibutyltin dioctoate and stannous oxalate, tetra -Organic titanium compounds such as -n-butyl titanate and tetraisopropyl titanate, iron salts, manganese salts, cobalt salts, zinc salts, zirconium salts and aluminum chelate compounds of organic carboxylic acids.

  In order to make application | coating easy, the solvent can be added to the coating liquid for protective layer formation as needed. Specific examples of the solvent include water, methanol, ethanol, n-propanol, i-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, Examples include ordinary organic solvents such as tetrahydrofuran, methylene chloride, chloroform, dimethyl ether, dibutyl ether and the like. These can be used individually by 1 type or in mixture of 2 or more types.

  In the formation of the protective layer 7, the application method of the coating liquid for forming the protective layer includes blade coating method, wire bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, curtain coating method, etc. Conventional methods can be used.

  The thickness of the protective layer 7 is preferably 0.5 to 20 μm, and more preferably 2 to 10 μm.

  In the electrophotographic photoreceptors 100 and 110, from the viewpoint of obtaining higher resolution, the total film thickness of the photosensitive layer 4 and the protective layer 7 is preferably 50 μm or less, and more preferably 40 μm or less. When this film thickness is small, the combination of the undercoat layers 2a and 2b and the high-strength protective layer 7 in this embodiment is particularly effective.

<Image forming apparatus and process cartridge>
Next, an image forming apparatus and a process cartridge equipped with the electrophotographic photosensitive member of the present invention will be described.

  FIG. 3 is a schematic cross-sectional view showing a preferred embodiment of the image forming apparatus of the present invention. An image forming apparatus 200 shown in FIG. 3 includes a drum-shaped (cylindrical) electrophotographic photosensitive member 30 of the present invention that is rotatably provided. Around the electrophotographic photosensitive member 30, along the movement direction of the outer peripheral surface of the electrophotographic photosensitive member 30, a charging device 8, an exposure device 10, a developing device 11, a transfer device 12, a cleaning device 13, and a static eliminator (erase). Device) 14 are arranged in this order.

  The charging device 8 is a charging device of a corona charging method that is a non-contact charging method, and charges the electrophotographic photosensitive member 30. Examples of the charging device 8 include a corotron charger and a scorotron charger. The charging device 8 is connected to a power source 9.

  The exposure apparatus 10 is for exposing the charged electrophotographic photosensitive member 30 to form an electrostatic latent image on the electrophotographic photosensitive member 30. For example, a semiconductor laser beam or LED light is formed on the surface of the photosensitive member 30. And optical system equipment that can expose light such as liquid crystal shutter light in a desired image-like manner. The wavelength of the light source is in the spectral sensitivity region of the photoreceptor. As the wavelength of the semiconductor laser, near infrared having an oscillation wavelength near 780 nm is the mainstream. However, the present invention is not limited to this wavelength, and an oscillation wavelength laser in the 600 nm range or a laser having an oscillation wavelength in the vicinity of 400 to 450 nm can be used as a blue laser. A surface-emitting laser light source capable of multi-beam output is also effective for color image formation.

  The developing device 11 is for developing a toner image by developing an electrostatic latent image with a developer. For example, a magnetic or non-magnetic one-component developer or a two-component developer is contacted or non-contacted. A general developing device for developing in contact is used. The developer preferably contains toner particles having a volume average particle diameter of 3 to 9 μm obtained by a polymerization method.

  The transfer device 12 is for transferring the toner image developed on the electrophotographic photosensitive member 30 to the transfer medium 20, for example, a contact type transfer charger using a belt, a roller, a film, a rubber blade or the like. A known transfer charger such as a scorotron transfer charger using corona discharge or a corotron transfer charger is used.

  The cleaning device 13 is for removing the toner remaining on the electrophotographic photosensitive member 30 after the transfer, and the electrophotographic photosensitive member thus cleaned is subjected to the next image forming process (electrophotographic process). Repeatedly served. As the cleaning device 13, in addition to a cleaning blade, brush cleaning, roll cleaning, and the like can be used. Among these, it is preferable to use a cleaning blade. Examples of the material for the cleaning blade include urethane rubber, neoprene rubber, and silicone rubber. The cleaning device 13 preferably has a blade member that comes into contact with the electrophotographic photosensitive member 30 at a linear pressure of 10 to 150 g / cm.

  The static eliminator (erase device) 14 is for erasing the residual charges of the electrophotographic photosensitive member 30 and preventing a phenomenon that the residual potential is brought into the next cycle, and includes, for example, an erase light irradiation device. Thereby, when the electrophotographic photosensitive member is repeatedly used, the image quality can be further improved. Note that the image forming apparatus of the present invention may have a configuration not including the static eliminator 14.

  Further, the image forming apparatus 200 includes a fixing device 15 that fixes the toner image on the transfer medium after the transfer process. The fixing device 15 is not particularly limited, and examples thereof include known fixing devices such as a heat roll fixing device and an oven fixing device.

  FIG. 4 is a schematic cross-sectional view showing another preferred embodiment of the image forming apparatus of the present invention. An image forming apparatus 210 shown in FIG. 4 has the same configuration as that of the image forming apparatus 200 shown in FIG. 3 except that it includes a charging device 8 that charges the electrophotographic photoreceptor 30 by a contact charging method. In particular, in the image forming apparatus 210 that employs a contact-type charging device in which an AC voltage is superimposed on a DC voltage, the electrophotographic photoreceptor 30 can be preferably used because it has excellent leakage resistance. In this case, the static eliminator 14 may not be provided.

  In the contact charging method, charging members such as a roller shape, a blade shape, a belt shape, a brush shape, and a magnetic brush shape are applicable. In particular, the roller-like or blade-like charging member may be arranged in a contact state or a non-contact state having a certain amount of gaps (100 μm or less) with respect to the electrophotographic photoreceptor 30.

A roller-shaped charging member, a blade-shaped charging member, and a belt-shaped charging member are composed of materials adjusted to an electric resistance (1 × 10 ³ Ω to 1 × 10 ⁸ Ω) effective as a charging member. It may be composed of a single layer or a plurality of layers.

  The material of the charging member is mainly composed of synthetic rubber such as urethane rubber, silicone rubber, fluorine rubber, chloroprene rubber, butadiene rubber, EPDM, epichlorohydrin rubber, and elastomers such as polyolefin, polystyrene, vinyl chloride, conductive carbon, An appropriate electrical conductivity imparting agent such as a metal oxide or an ionic conductive agent can be blended in an appropriate amount to develop an effective electrical resistance as a charging member.

  Furthermore, a paint obtained by converting a resin such as nylon, polyester, polystyrene, polyurethane, silicone, etc. into a paint, and blending an appropriate amount of any conductivity imparting agent such as conductive carbon, metal oxide, ionic conductive agent, It can be used by laminating by any method such as dipping, spraying, roll coating and the like.

  On the other hand, for brush-shaped charging members, a conventional fiber-impregnated fiber such as acrylic, nylon, polyester, etc., is impregnated with fluorine, and then transplanted using an existing method, and brush-shaped charging is performed. A member can be produced. Further, after various fibers are formed on the brush-shaped charging member, fluorine impregnation treatment may be performed.

  The brush-shaped charging member referred to here may be any of a roller-shaped charging member and a brushed charging member, and the shape thereof is not particularly limited. Further, the magnetic brush-like charging member is a magnetically arranged ferrite, magite, etc., radially arranged on the outer periphery of the cylinder containing the multipolar magnet, and after pre-applied fluorine, magite, etc. A magnetic brush is desirable.

  FIG. 5 is a schematic cross-sectional view showing another preferred embodiment of the image forming apparatus of the present invention. The image forming apparatus 220 is an image forming apparatus of a tandem type intermediate transfer system. In the housing 400, four electrophotographic photosensitive members 401a to 401d (for example, 401a is yellow, 401b is magenta, 401c is cyan, 401d is black). Color images can be formed respectively) along the intermediate transfer belt 409 and arranged in parallel with each other.

  Conventionally, as a method for transferring a visible image onto a transfer paper such as paper, a transfer drum method for winding a transfer paper such as paper around a transfer drum and transferring the visible image on the photosensitive member to the transfer paper for each color, etc. It has been known. In this case, compared with the tandem intermediate transfer method, the transfer of the visible image from the photosensitive member to the intermediate transfer member had to rotate the intermediate transfer member a plurality of times. This is a promising transfer method in the future because it can be transferred from a plurality of photoconductors 401a to 401d by making one rotation 409, and transfer speed can be improved, and a transfer medium can be selected as in the transfer drum method. .

  Here, the electrophotographic photoreceptors 401 a to 401 d mounted on the image forming apparatus 220 are the same as the electrophotographic photoreceptor 30.

  Each of the electrophotographic photosensitive members 401a to 401d can be rotated in a predetermined direction (counterclockwise on the paper surface), and the charging rolls 402a to 402d, the developing devices 404a to 404d, and the primary transfer roll 410a along the rotation direction. To 410d and cleaning devices 415a to 415d are arranged. Each of the developing devices 404a to 404d can be supplied with toners of four colors, yellow, magenta, cyan, and black accommodated in toner cartridges 405a to 405d. Further, the primary transfer rolls 410a to 410d are in contact with the electrophotographic photosensitive members 401a to 401d via the intermediate transfer belt 409, respectively.

  Further, a laser light source (exposure device) 403 is disposed at a predetermined position in the housing 400. Laser light emitted from the laser light source 403 can be applied to the surfaces of the charged electrophotographic photoreceptors 401a to 401d. Accordingly, charging, exposure, development, primary transfer, and cleaning are sequentially performed in the rotation process of the electrophotographic photosensitive members 401a to 401d, and the toner images of the respective colors are transferred onto the intermediate transfer belt 409 in an overlapping manner.

  The intermediate transfer belt 409 is supported with a predetermined tension by a drive roll 406, a backup roll 408, and a tension roll 407, and can rotate without causing deflection due to the rotation of these rolls. Further, the secondary transfer roll 413 is disposed so as to contact the backup roll 408 via the intermediate transfer belt 409. The intermediate transfer belt 409 passing between the backup roll 408 and the secondary transfer roll 413 is cleaned by, for example, a cleaning blade 416 disposed in the vicinity of the drive roll 406 and then repeatedly used for the next image forming process. Is done.

  A tray (transfer medium tray) 411 is provided at a predetermined position in the housing 400, and the transfer medium 500 such as paper in the tray 411 is moved by the intermediate transfer belt 409 and the secondary transfer roll by the transfer roll 412. Then, the paper is sequentially transferred between the two fixing rolls 414 that are in contact with each other and the two fixing rolls 414, and then discharged to the outside of the housing 400.

  In the above description, the case where the intermediate transfer belt 409 is used as the intermediate transfer member has been described. However, the intermediate transfer member may have a belt shape (for example, an endless belt shape) like the intermediate transfer belt 409. It may be a drum shape. When a belt-shaped configuration such as the intermediate transfer belt 409 is employed as the intermediate transfer member, generally the film thickness of the belt is preferably 50 to 500 μm, and more preferably 60 to 150 μm. In addition, the film thickness of a belt can be suitably selected according to the hardness of material. When a drum-shaped configuration is adopted as the intermediate transfer member, it is preferable to use a cylindrical substrate formed of aluminum, stainless steel (SUS), copper, or the like as the substrate. If necessary, an elastic layer can be coated on the cylindrical substrate, and a surface layer can be formed on the elastic layer.

  The transfer medium referred to in the present invention is not particularly limited as long as it is a medium for transferring a toner image formed on an electrophotographic photosensitive member. For example, when transferring directly from an electrophotographic photosensitive member to paper or the like, paper or the like is a transfer medium, and when an intermediate transfer member is used, the intermediate transfer member is a transfer medium.

  As the material of the endless belt, heat such as polycarbonate resin (PC), polyvinylidene fluoride (PVDF), polyalkylene phthalate, PC / polyalkylene phthalate (PAT) blend material, ethylene tetrafluoroethylene copolymer (ETFE), etc. A semiconductive endless belt made of a plastic resin has been proposed.

  Japanese Patent No. 2560727, Japanese Patent Application Laid-Open No. 5-77252, etc. propose an intermediate transfer member in which ordinary carbon black is dispersed as a conductive fine powder in a polyimide resin.

  Since the polyimide resin is a material having a high Young's modulus, it is less likely to be deformed by driving (stress of a support roll, a cleaning blade, etc.), so that it becomes an intermediate transfer body in which image defects such as color misregistration are unlikely to occur. A polyimide resin is usually obtained as a polyamic acid solution by polymerizing a substantially equimolar amount of tetracarboxylic dianhydride or its derivative and a diamine in a solvent. As tetracarboxylic dianhydride, what is shown by the following general formula (XV) is mentioned, for example.

［式中、Ｒは、脂肪族鎖式炭化水素基、脂肪族環式炭化水素基及び芳香族炭化水素基、並びにこれらの炭化水素基に置換基が結合した基からなる群より選ばれる４価の有機基を示す。］

[Wherein, R is a tetravalent group selected from the group consisting of an aliphatic chain hydrocarbon group, an aliphatic cyclic hydrocarbon group, an aromatic hydrocarbon group, and a group in which a substituent is bonded to these hydrocarbon groups. An organic group of ]

  Specific examples of the tetracarboxylic dianhydride include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, and 3,3 ′, 4,4′-biphenyltetracarboxylic acid. Acid dianhydride, 2,3,3 ′, 4-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid Dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2′-bis (3,4-dicarboxyphenyl) sulfonic dianhydride, perylene-3,4,9,10 -Tetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, ethylenetetracarboxylic dianhydride, etc. are mentioned.

On the other hand, specific examples of the diamine include 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 3,3′-diaminodiphenylmethane, 3,3′-dichlorobenzidine, 4,4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenylsulfone, 1,5-diaminonaphthalene, m-phenylenediamine, p-phenylenediamine, 3,3′-dimethyl-4,4′-biphenyldiamine, benzidine, 3,3′-dimethylbenzidine 3,3′-dimethoxybenzidine, 4,4′-diaminodiphenylsulfone, 4,4′-diaminodiphenylpropane, 2,4-bis (β-aminotert-butyl) toluene, bis (p-β-amino- Tert-butylphenyl) ether, bis (p-β-methyl-δ-aminophenyl) benzene, bis p- (1,1-dimethyl-5-amino-benzyl) benzene, 1-isopropyl-2,4-m-phenylenediamine, m-xylylenediamine, p-xylylenediamine, di (p-aminocyclohexyl) methane , Hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, diaminopropyltetramethylene, 3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 2,11-diaminododecane, 1 , 2-bis-3-aminopropoxyethane, 2,2-dimethylpropylenediamine, 3-methoxyhexamethylenediamine, 2,5-dimethylheptamethylenediamine, 3-methylheptamethylenediamine, 5-methylnonamethylenediamine, 2, 17-diaminoeicosadecane, 1,4-diaminocyclohexane, 1,10-diamino-1,10-dimethyldecane, 12-diaminooctadecane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, _{piperazine, H 2 N (CH 2)} 3 O (CH 2) 2 O (CH 2) NH 2, H 2 N (CH 2) 3 S (CH 2) 3 NH 2, H 2 N (CH 2) 3 N _{(CH 3) 2 (CH 2} ) 3 NH 2 and the like.

  As the solvent for the polymerization reaction of tetracarboxylic dianhydride and diamine, a polar solvent is preferably used from the viewpoint of solubility. As the polar solvent, N, N-dialkylamides are preferable, and specific examples thereof include N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylformamide, which are low molecular weight compounds thereof. N, N-diethylacetamide, N, N-dimethylmethoxyacetamide, dimethyl sulfoxide, hexamethylphosphortriamide, N-methyl-2-pyrrolidone, pyridine, tetramethylenesulfone, dimethyltetramethylenesulfone and the like. These can be used individually by 1 type or in combination of 2 or more types.

  The intermediate transfer member contains oxidized carbon black in a polyimide resin. Oxidized carbon black can be obtained by oxidizing carbon black to give an oxygen-containing functional group (for example, carboxyl group, quinone group, lactone group, hydroxyl group, etc.) to the surface.

  This oxidation treatment is an air oxidation method in which contact is caused to react with air in a high temperature atmosphere, a method in which it reacts with nitrogen oxide or ozone at room temperature, and a method in which ozone oxidation is performed at low temperature after air oxidation at high temperature. Etc.

  Specific examples of the oxidized carbon include MA100 (pH 3.5, volatile matter 1.5%), MA100R (pH 3.5, volatile matter 1.5%), and MA100S (pH 3.5, volatile matter) manufactured by Mitsubishi Chemical. 1.5%), # 970 (pH 3.5, volatile content 3.0%), MA11 (pH 3.5, volatile content 2.0%), # 1000 (pH 3.5, volatile content 3.). 0%), # 2200 (pH 3.5, volatile content 3.5%), MA 230 (pH 3.0, volatile content 1.5%), MA 220 (pH 3.0, volatile content 1.0%), # 2650 (pH 3.0, volatile content 8.0%), MA7 (pH 3.0, volatile content 3.0%), MA8 (pH 3.0, volatile content 3.0%), OIL7B (pH 3) 0.0, volatile content 6.0%), MA77 (pH 2.5, volatile content 3.0%), # 2350 (pH) .5, volatile content 7.5%), # 2700 (pH 2.5, volatile content 10.0%), # 2400 (pH 2.5, volatile content 9.0%), Dexa Printex 150T (PH 4.5, volatile content 10.0%), Special Black 350 (pH 3.5, volatile content 2.2%), Special Black 100 (pH 3.3, volatile content 2.2%), Special Black 250 (pH 3.1, volatile content 2.0%), Special Black 5 (pH 3.0, volatile content 15.0%), Special Black 4 (pH 3.0, volatile content 14.0%), Special Black 4A (pH 3.0, volatile content 14.0%), Special Black 550 (pH 2.8, volatile content 2.5%), Special Black 6 (pH 2.5, volatile content 18.0%), Color black FW20 (PH 2.5, volatile content 20.0%), same color black FW2 (pH 2.5, volatile content 16.5%), same color black FW2V (pH 2.5, volatile content 16.5%), manufactured by Cabot Corporation MONARCH 1000 (pH 2.5, volatile content 9.5%), MONARCH 1300 (pH 2.5, volatile content 9.5%) manufactured by Cabot, MONARCH 1400 (pH 2.5, volatile content 9.0%) manufactured by Cabot, MOGUL -L (pH 2.5, volatile matter 5.0%), REGAL400R (pH 4.0, volatile matter 3.5%) and the like.

  The oxidation-treated carbon black obtained in this way has an excessive current flowing in part, and is not easily affected by oxidation due to repeated voltage application. Furthermore, due to the effect of the oxygen-containing functional group attached to the surface, the dispersibility in polyimide is high, the resistance variation can be reduced, the electric field dependency is also reduced, and the electric field concentration due to the transfer voltage is less likely to occur. .

  As a result, resistance degradation due to transfer voltage is prevented, uniformity of electrical resistance is improved, electric field dependency is small, resistance change due to the environment is small, and image quality defects such as whitening of the paper running part occur. The intermediate transfer member can obtain a suppressed high image quality. When two or more kinds of oxidized carbon blacks are added, these oxidized carbon blacks are preferably substantially different in conductivity from each other. For example, the BET method utilizing the degree of oxidation treatment, DBP oil absorption, and nitrogen adsorption Those having different physical properties such as specific surface area are used. When two or more types of carbon blacks having different physical properties are added as described above, for example, carbon black exhibiting high conductivity is preferentially added, and then carbon black having low conductivity is added to adjust the surface resistivity. It is possible.

  Specific examples of the oxidized carbon black include SPECIAL BLACK4 (Degussa, pH 3.0, volatile content: 14.0%), SPECIAL BLACK250 (Degussa, pH 3.1, volatile content: 2.0%), and the like. Is mentioned. The content of these oxidized carbon blacks is preferably about 10 to 50% by mass, more preferably 12 to 30% by mass with respect to the polyimide resin. If this content is less than 10% by mass, the uniformity of electrical resistance may be reduced, and the decrease in surface resistivity during durable use may increase. On the other hand, if it exceeds 50% by mass, the desired resistance value may be obtained. Is not preferred, and it is not preferable because it becomes brittle as a molded product.

  The intermediate transfer body made of polyimide resin in which oxidized carbon black is dispersed performs a step of preparing a polyamic acid solution in which oxidized carbon black is dispersed, a step of forming a film (layer) on the inner surface of a cylindrical mold, and imide conversion It can be obtained through a process.

  About the manufacturing method of the polyamic acid solution which disperse | distributed 2 or more types of oxidation treatment carbon black, the said acid dianhydride component and diamine component are contained in the dispersion liquid which disperse | distributed 2 or more types of oxidation treatment carbon black beforehand in the solvent. Method of dissolving and polymerizing Two or more types of oxidized carbon black are each dispersed in a solvent to prepare two or more types of carbon black dispersions, and the acid anhydride component and the diamine component are dissolved and polymerized in this dispersion. Thereafter, a method of mixing each polyamic acid solution, etc. can be considered, and a polyamic acid solution in which carbon black is dispersed is prepared by selecting as appropriate.

  The intermediate transfer member is obtained by supplying and spreading the polyamic acid solution thus obtained on the inner surface of the cylindrical mold to form a coating film, and converting the polyamic acid to imide by heating. In this imide conversion, an intermediate transfer member having good flatness can be obtained by holding at a predetermined temperature for 0.5 hour or more.

  Examples of a supply method for supplying the polyamic acid solution to the inner surface of the cylindrical mold include a method using a dispenser and a method using a die. Here, as the cylindrical mold, it is preferable to use a mirror-finished inner peripheral surface.

  Examples of the method of forming a film from the polyamic acid solution supplied to the mold include a method of centrifugal molding while heating, a method of molding using a bullet-shaped traveling body, a method of rotational molding, and the like. A film having a uniform film thickness is formed by the method.

  The method for forming the intermediate transfer body by converting the thus formed film into an imide is (i) a method in which the mold is placed in a dryer and the temperature is raised to a reaction temperature for imide conversion, and (ii) a belt. As a method, after removing the solvent until the shape can be maintained, the film is peeled off from the inner surface of the mold and replaced with the outer surface of the metal cylinder, and then the imide conversion is performed by heating the entire cylinder. In order to obtain an intermediate transfer member having good flatness and outer surface accuracy, the method (ii) described above, in which the solvent is removed until it can be held as a belt, and then replaced with a metal cylinder for imide conversion.

  In the above method (ii), the heating conditions for removing the solvent are not particularly limited as long as the solvent can be removed, but the heating temperature is preferably 80 to 200 ° C., and the heating time is 0.5 to 5 hours. It is preferable. In this way, the molded product that can retain its shape as a belt is peeled off from the inner peripheral surface of the mold. At this time, a mold release process can be performed on the inner peripheral surface of the mold.

  Next, the molded product heated and cured until it can be held as a belt shape is replaced with the outer surface of the metal cylinder, and the replaced cylinder is heated to advance the imide conversion reaction of the polyamic acid. As such a metal cylinder, one having a linear expansion coefficient larger than that of polyimide resin is preferable, and by setting the outer diameter of the cylinder to be a predetermined amount smaller than the inner diameter of the polyimide molding, a uniform film can be formed. An endless belt having a uniform thickness can be obtained. Moreover, it is preferable that the centerline average surface roughness (Ra) of a metal cylinder outer surface is 1.2-2.0 micrometers. If the center line average surface roughness (Ra) of the outer surface of the metal cylinder is less than 1.2 μm, the metal cylinder itself is too smooth, and slippage due to contraction in the belt axial direction does not occur in the obtained intermediate transfer member. Stretching is performed in this step, which may cause variations in film thickness and a decrease in flatness accuracy. If the surface roughness (Ra) of the outer surface of the metal cylinder exceeds 2.0 μm, the outer surface of the metal cylinder is transferred to the inner surface of the belt-shaped intermediate transfer body, and further, irregularities are generated on the outer surface. May be more likely to occur. In addition, the surface roughness as used in the field of this invention means Ra measured according to JISB601.

  Moreover, although it is based also on a composition of a polyimide resin as a heating condition in the case of imide conversion, it is preferable that heating temperature is 220-280 degreeC and heating time is 0.5 to 2 hours. When imide conversion is performed under such heating conditions, the amount of shrinkage of the polyimide resin becomes larger, and therefore, the shrinkage in the axial direction of the belt is gently performed to prevent a decrease in film thickness variation and flatness accuracy. Can do.

  The centerline average surface roughness (Ra) of the outer surface of the intermediate transfer member made of polyimide resin thus obtained is preferably 1.5 μm or less. If the center line average surface roughness (Ra) of the intermediate transfer member exceeds 1.5 μm, image defects such as roughness are likely to occur. Note that the occurrence of roughness is a resistance caused by the appearance of a new conductive path due to the voltage applied during transfer and the electric field due to the peeling discharge being locally concentrated on the convex portion of the belt surface and deteriorating the convex surface. Is considered to be caused by a decrease in the density of the resulting image.

  The intermediate transfer member thus obtained has a flatness of 5 mm or less, preferably 3 mm or less. When the flatness is 5 mm or less, there is no roughness and color deviation is small. However, when the belt end portion is bent vertically, even if the flatness is 5 mm or less, it does not break during use of the intermediate transfer member, but it rarely remains after contacting the peripheral member. Further, when the flatness is 3 mm or less, the intermediate transfer member is not brought into contact with the peripheral member during use and there is almost no color shift.

  FIG. 6 is a schematic cross-sectional view showing a preferred embodiment of the process cartridge of the present invention. The process cartridge 300 is integrated with the electrophotographic photosensitive member 30 of the present invention by combining the charging unit 8, the developing unit 11, the cleaning unit 13, the opening 18 for exposure, and the static eliminator 14 using the mounting rail 16. It is a thing. The process cartridge 300 is detachable from the main body of the image forming apparatus including the transfer unit 12, the fixing unit 15, and other components (not shown). It constitutes. Such a process cartridge 300 can be applied to any of the image forming apparatuses shown in FIGS.

  According to the image forming apparatus and the process cartridge of the present invention, since the electrophotographic photosensitive member of the present invention is used, it is possible to stably form an image with good image quality over a long period of time.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

<Production of electrophotographic photoreceptor>
Example 1-A
First, a cylindrical aluminum substrate (diameter 30 mm, length 404 mm, wall thickness 1 mm) was prepared.

On the other hand, 60 parts by mass of zinc oxide particles (manufactured by Teika, “MZ150”, volume average particle diameter 70 nm, specific surface area value 10 to 16 m ² / g), blocked isocyanate (“Sumijour 3175”, Sumitomo Bayern) as a curing agent 13.5 parts by mass of Urethane Co., Ltd., 10 parts by mass of butyral resin (“BM-1”, Sekisui Chemical Co., Ltd.) and 90 parts by mass of methyl ethyl ketone were mixed. Next, with respect to 57 parts by mass of this solution, 1 mmφ glass beads were used (a glass bead filling rate of 80% by volume), and dispersion was performed for 2 hours with a sand mill to obtain a dispersion. As a catalyst, 0.005 parts by mass of dioctyltin dilaurate and 4.0 parts by mass of silicone resin particles (“Tospearl 145”, manufactured by GE Toshiba Silicone) are added to 100 parts by mass of the resulting dispersion, and an undercoat layer is added. A forming coating solution was obtained. This coating solution was applied onto an aluminum substrate by a dip coating method, followed by drying and curing at 170 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 25 μm.

  Next, a silane coupling agent-containing layer was formed on the undercoat layer by the following procedure.

First, 100 parts by mass of zinc oxide (manufactured by Teica, “MZ150”, volume average particle diameter 70 nm, specific surface area value 15 m ² / g), 400 parts by mass of toluene, and 100 parts by mass of methanol are mixed with stirring to obtain a silane cup. 2.5 parts by mass of a ring agent (“KBM603”, manufactured by Shin-Etsu Chemical Co., Ltd.) was added and stirred for 2 hours. Thereafter, the solvent was distilled off under reduced pressure, and baking was performed at 120 ° C. for 3 hours to obtain a silane coupling agent surface-treated zinc oxide.

  Next, 60 parts by mass of the silane coupling agent surface-treated zinc oxide obtained above, 0.3 parts by mass of alizarin, and 13 blocked isocyanate (“Sumidule 3175”, manufactured by Sumitomo Bayern Urethane Co., Ltd.) as a curing agent are used. 0.5 part by mass, 10 parts by mass of butyral resin (“BM-1”, manufactured by Sekisui Chemical Co., Ltd.) and 90 parts by mass of methyl ethyl ketone were mixed. Next, with respect to 57 parts by mass of this solution, 1 mmφ glass beads were used (a glass bead filling rate of 80% by volume), and dispersion was performed for 2 hours with a sand mill to obtain a dispersion. As a catalyst, 0.005 part by mass of dioctyltin dilaurate and part by mass of methyl ethyl ketone 20 were added to 100 parts by mass of the resulting dispersion to obtain a coating liquid for forming a silane coupling agent-containing layer. This coating solution was applied onto the undercoat layer by a dip coating method, followed by drying and curing at 170 ° C. for 40 minutes to form a silane coupling agent-containing layer having a thickness of 1 μm.

  Next, 15 mass of hydroxygallium phthalocyanine having strong diffraction peaks at Bragg angles (2θ ± 0.2 °) of at least 7.3 °, 16.0 °, 24.9 °, and 28.0 ° in the X-ray diffraction spectrum. Parts were mixed with 10 parts by weight of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nihon Unicar) and 200 parts by weight of n-butyl acetate, and this was dispersed with a glass bead having an outer diameter of 1 mm for 4 hours in a sand mill. . A coating solution for forming a charge generation layer was prepared by adding 175 parts by mass of n-butyl acetate and 180 parts by mass of methyl ethyl ketone to the obtained dispersion. The obtained coating solution was dip-coated on the silane coupling agent-containing layer and dried at room temperature to form a charge generation layer having a thickness of 0.2 μm.

Next, tetrafluoroethylene resin particles (manufactured by Daikin Industries, Ltd., “Lublon L-2”, volume average particle diameter 0.2 μm) 1 part by mass and fluorine-based graft polymer (manufactured by Toagosei Co., Ltd., “GF300”) 0.02 part by mass was sufficiently stirred and mixed with 5 parts by mass of tetrahydrofuran and 2 parts by mass of toluene to obtain a tetrafluoroethylene resin particle suspension. On the other hand, 4 parts by mass of N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1 ′] biphenyl-4,4′-diamine and a bisphenol Z-type polycarbonate resin ( 6 parts by mass of viscosity average molecular weight 40,000) was mixed and dissolved in 23 parts by mass of tetrahydrofuran and 10 parts by mass of toluene. After adding the tetrafluoroethylene resin particle suspension to this solution and stirring and mixing, using a high-pressure homogenizer (trade name LA-33S, manufactured by Nanomizer Co., Ltd.) equipped with a through-type chamber having fine flow paths. The dispersion treatment under pressure up to 400 kgf / cm ² was repeated 6 times to obtain a tetrafluoroethylene resin particle dispersion. Further, 0.2 parts by mass of 2,6-di-t-butyl-4-methylphenol was mixed with this to obtain a coating solution for forming a charge transport layer. This coating solution is applied onto the charge generation layer and dried at 115 ° C. for 40 minutes to form a charge transport layer having a thickness of 32 μm. On the aluminum substrate, an undercoat layer, a silane coupling agent-containing layer, a charge generation layer An electrophotographic photosensitive member provided with a charge transport layer in this order was obtained. This electrophotographic photosensitive member was designated as PR-1-A.

(Example 2-A)
An electrophotographic photoreceptor was obtained in the same manner as in Example 1-A, except that the following silane coupling agent-containing layer was formed instead of the intermediate layer in Example 1-A. This electrophotographic photosensitive member was designated as PR-2-A.

For forming a silane coupling agent-containing layer, first, 60 parts by mass of zinc oxide particles (manufactured by Teika, “MZ150”, volume average particle diameter 70 nm, specific surface area value 15 m ² / g), blocked isocyanate as a curing agent 13.5 parts by mass (“Sumijour 3175”, manufactured by Sumitomo Bayern Urethane Co., Ltd.), 10 parts by mass of butyral resin (“BM-1”, manufactured by Sekisui Chemical Co., Ltd.) and 90 parts by mass of methyl ethyl ketone were mixed. Next, with respect to 57 parts by mass of this solution, 1 mmφ glass beads were used (a glass bead filling rate of 80% by volume), and dispersion was performed for 2 hours with a sand mill to obtain a dispersion. As a catalyst, 0.005 part by mass of dioctyltin dilaurate, 10 parts by mass of a silane coupling agent (“KBM603”, manufactured by Shin-Etsu Chemical Co., Ltd.), and 20 parts by mass of methyl ethyl ketone are added to 100 parts by mass of the obtained dispersion. A coating solution for forming a coupling agent-containing layer was obtained. This coating solution was applied onto the undercoat layer by a dip coating method, followed by drying and curing at 170 ° C. for 40 minutes to form a silane coupling agent-containing layer having a thickness of 3 μm.

Example 3-A
An electrophotographic photosensitive member was obtained in the same manner as in Example 1-A except that the following silane coupling agent-containing layer was formed instead of the silane coupling agent-containing layer in Example 1-A. This electrophotographic photosensitive member was designated as PR-3-A.

  For forming a silane coupling agent-containing layer, first, 100 parts by mass of methanol and 25 parts by mass of a silane coupling agent (“KBM603”, manufactured by Shin-Etsu Chemical Co., Ltd.) are mixed and stirred to form a coating solution for forming a silane coupling agent-containing layer. Got. This coating solution was applied onto the undercoat layer by a dip coating method, followed by drying and curing at 170 ° C. for 10 minutes to form a silane coupling agent-containing layer having a thickness of 0.1 μm.

(Example 4-A) to (Example 6-A)
Each of the electrophotographic photoreceptors was the same as Example 1-A to Example 3-A except that the following undercoat layer was formed instead of the undercoat layer in Example 1-A to Example 3-A. Got. These electrophotographic photoreceptors were designated as PR-4-A, PR-5-A, and PR-6-A, respectively.

In order to form the undercoat layer, first, 100 parts by mass of zinc oxide (manufactured by Teica, “MZ150”, volume average particle diameter 70 nm, specific surface area value 15 m ² / g), 400 parts by mass of toluene, and 100 parts by mass of methanol And silane coupling agent (“KBM603”, manufactured by Shin-Etsu Chemical Co., Ltd.) was added in an amount of 0.8 parts by mass, and the mixture was stirred for 2 hours. Thereafter, the solvent was distilled off under reduced pressure, and baking was performed at 120 ° C. for 3 hours to obtain a silane coupling agent surface-treated zinc oxide.

  Next, 60 parts by mass of the silane coupling agent surface-treated zinc oxide obtained above, 13.5 parts by mass of blocked isocyanate (“Sumidule 3175”, manufactured by Sumitomo Bayern Urethane Co., Ltd.) as a curing agent, butyral resin ( 10 parts by mass of “BM-1” (manufactured by Sekisui Chemical Co., Ltd.), 72 parts by mass of methyl ethyl ketone and 18 parts by mass of n-hexane were mixed. Next, with respect to 57 parts by mass of this solution, 1 mmφ glass beads were used (a glass bead filling rate of 80% by volume), and dispersion was performed for 2 hours with a sand mill to obtain a dispersion. As a catalyst, 0.005 parts by mass of dioctyltin dilaurate and 4.0 parts by mass of silicone resin particles (“Tospearl 145”, manufactured by GE Toshiba Silicone) are added to 100 parts by mass of the resulting dispersion, and an undercoat layer is added. A forming coating solution was obtained. This coating solution was applied onto an aluminum substrate by a dip coating method, followed by drying and curing at 170 ° C. for 40 minutes to form an undercoat layer having a thickness of 25 μm.

(Example 7-A) to (Example 9-A)
Each of the electrophotographic photoreceptors was the same as Example 1-A to Example 3-A except that the following undercoat layer was formed instead of the undercoat layer in Example 1-A to Example 3-A. Got. These electrophotographic photosensitive members were designated as PR-7-A, PR-8-A, and PR-9-A, respectively.

In order to form the undercoat layer, first, 100 parts by mass of zinc oxide (manufactured by Teica, “MZ150”, volume average particle diameter 70 nm, specific surface area value 15 m ² / g), 400 parts by mass of toluene, and 100 parts by mass of methanol And silane coupling agent (“KBM603”, manufactured by Shin-Etsu Chemical Co., Ltd.) was added in an amount of 0.8 parts by mass, and the mixture was stirred for 2 hours. Thereafter, the solvent was distilled off under reduced pressure, and baking was performed at 120 ° C. for 3 hours to obtain a silane coupling agent surface-treated zinc oxide.

  Next, 60 parts by mass of the silane coupling agent surface-treated zinc oxide obtained above, 0.3 parts by mass of alizarin, and 13 blocked isocyanates (“Sumijoule 3175”, manufactured by Sumitomo Bayern Urethane Co., Ltd.) as a curing agent are used. 0.5 parts by mass, 10 parts by mass of butyral resin (“BM-1”, manufactured by Sekisui Chemical Co., Ltd.), 72 parts by mass of methyl ethyl ketone and 18 parts by mass of n-hexane were mixed. Next, with respect to 57 parts by mass of this solution, 1 mmφ glass beads were used (a glass bead filling rate of 80% by volume), and dispersion was performed for 2 hours with a sand mill to obtain a dispersion. As a catalyst, 0.005 parts by mass of dioctyltin dilaurate and 4.0 parts by mass of silicone resin particles (“Tospearl 145”, manufactured by GE Toshiba Silicone) are added to 100 parts by mass of the resulting dispersion, and an undercoat layer is added. A forming coating solution was obtained. This coating solution was applied onto an aluminum substrate by a dip coating method, followed by drying and curing at 170 ° C. for 40 minutes to form an undercoat layer having a thickness of 25 μm.

(Example 10-A)
First, a cylindrical aluminum substrate (diameter 30 mm, length 404 mm, wall thickness 1 mm) was prepared.

Meanwhile, 60 parts by mass of zinc oxide particles (manufactured by Teika, “MZ150”, volume average particle diameter 70 nm, specific surface area value 15 m ² / g), blocked isocyanate (“Sumidule 3175”, Sumitomo Bayern Urethane Co., Ltd.) as a curing agent 13.5 parts by mass, butyral resin (“BM-1”, manufactured by Sekisui Chemical Co., Ltd.) 10 parts by mass and 90 parts by mass of methyl ethyl ketone were mixed. Next, with respect to 57 parts by mass of this solution, 1 mmφ glass beads were used (a glass bead filling rate of 80% by volume), and dispersion was performed for 2 hours with a sand mill to obtain a dispersion. As a catalyst, 0.005 parts by mass of dioctyltin dilaurate and 4.0 parts by mass of silicone resin particles (“Tospearl 145”, manufactured by GE Toshiba Silicone) are added to 100 parts by mass of the resulting dispersion, and an undercoat layer is added. A forming coating solution was obtained. This coating solution was applied onto an aluminum substrate by a dip coating method and dried at room temperature for 20 minutes. Subsequently, this substrate was mixed at a temperature of 20 ° C. in a solution (immersion treatment liquid A) in which 100 parts by mass of methyl ethyl ketone and 25 parts by mass of a silane coupling agent (“KBM603”, manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed and stirred. Submerged and pulled up, dried and cured at 170 ° C. for 40 minutes to form an undercoat layer having a thickness of 25 μm.

  Next, in the same manner as the formation of the charge generation layer and the charge transport layer in Example 1-A, the charge generation layer and the charge transport layer were formed in this order on the undercoat layer to obtain an electrophotographic photosensitive member. This electrophotographic photosensitive member was designated as PR-10-A.

(Comparative Example 1-A)
The amount of the silane coupling agent used for the surface treatment of zinc oxide particles in Example 4-A was changed from 0.8 parts by mass to 1.25 parts by mass, and an undercoat layer was formed, and the silane coupling agent was contained. An electrophotographic photosensitive member was obtained in the same manner as in Example 4-A except that no layer was provided. This electrophotographic photosensitive member was designated as RPR-1-A.

(Comparative Example 2-A)
An electrophotographic photosensitive member was obtained in the same manner as in Example 4-A, except that the silane coupling agent-containing layer in Example 4-A was not provided. This electrophotographic photosensitive member was designated as RPR-2-A.

(Comparative Example 3-A)
In the formation of the undercoat layer and the silane coupling agent-containing layer in Example 4-A, the amount of the silane coupling agent used for the surface treatment of the zinc oxide particles was changed from 0.8 parts by mass to 2.5 parts by mass. An electrophotographic photosensitive member was obtained in the same manner as in Example 4-A except that a pulling layer was formed and a silane coupling agent-containing layer was not provided. This electrophotographic photosensitive member was designated as RPR-3-A.

(Comparative Example 4-A)
In the formation of the undercoat layer and the silane coupling agent-containing layer in Example 4-A, the amount of the silane coupling agent used for the surface treatment of the zinc oxide particles was changed from 0.8 parts by mass to 2.5 parts by mass. Except for forming the pulling layer and changing the amount of the silane coupling agent used for the surface treatment of the zinc oxide particles from 2.5 parts by mass to 0.8 parts by mass to form the silane coupling agent-containing layer. An electrophotographic photoreceptor was obtained in the same manner as Example 4-A. This electrophotographic photosensitive member was designated as RPR-4-A.

  The electrophotographic photoreceptors “PR-1-A” to “PR-10-A” obtained in Examples (1-A) to (10-A) and Comparative Examples (1-A) to (4-A) About the electrophotographic photoreceptors “RPR-1-A” to “RPR-4-A” obtained in 1 above, the amount of the silane coupling agent blended when the undercoat layer and the silane coupling agent-containing layer were formed Are summarized in Table 64. In addition, the compounding quantity of the silane coupling agent was shown by the compounding ratio on the basis of the solid content whole quantity of the layer in which a silane coupling agent is contained.

＊１：浸漬処理液Ａに浸漬する前の下引層におけるシランカップリング剤の配合割合０質量％（固形分全量基準）、浸漬処理液Ａ中のシランカップリング剤の配合割合１００質量％（固形分全量基準）。

* 1: 0% by mass of the silane coupling agent in the undercoat layer before being immersed in the immersion treatment liquid A (based on the total solid content), 100% by mass of the silane coupling agent in the immersion treatment liquid A ( Based on the total solid content).

(Examples 1-B to 10-B and Comparative Examples 1-B to 4-B)
The electrophotographic photoreceptors “PR-1-A” to “PR-10-A” obtained in Examples (1-A) to (10-A) and Comparative Examples (1-A) to (4-A) The electrophotographic photoreceptors “RPR-1-A” to “RPR-4-A” obtained in 1 above are mounted on a full color printer Docu Center Color C400 manufactured by Fuji Xerox Co., Ltd., which includes a contact charging device and an intermediate transfer device. A forming apparatus was produced and the following actual machine running test was performed.

<Real machine running test>
Using the image forming apparatus produced as described above, the environment of high temperature and high humidity (28 ° C., 85% RH) and low temperature and low humidity (15 ° C., 10% RH) is changed every 10 image formations. Image formation (A4 size) was continuously performed on 50,000 sheets. Then, the evaluation of ghost and fog / spot was performed based on the following method. The results obtained are shown in Table 65.

(Ghost evaluation)
In an environment of 20 ° C. and 40% RH, an arbitrary number of 15 mm square patterns are printed for one round of the electrophotographic photosensitive member as a ghost evaluation image, and then the entire halftone image is printed in the next cycle. The ghost image that appeared on the halftone image was evaluated based on the following criteria.
A: No ghost is seen in the image.
B: A little ghost is seen in the image.
C: A ghost is clearly seen in the image.

(Cover, sunspot)
After the actual machine running test, an image was formed in an environment of 28 ° C. and 85% RH, and the image quality (fogging and black spots on a white background) at that time was evaluated based on the following evaluation criteria.
A: Neither fog nor black spots are seen in the image.
B: A slight fog or black spot is observed in the image.
C: A fog or a black spot is seen in the image.

<Evaluation of cycle characteristics>
Before and after the actual machine running test, the residual potential on the surface of the electrophotographic photosensitive member was measured as follows.

Under normal temperature and humidity (20 ° C., 40% RH), the photoconductor was rotated at 100 rpm and charged with a scorotron charger to −700 V, and a semiconductor laser having a wavelength of 780 nm was used 1 second after charging. Irradiate light with 10.0 erg / cm ² to discharge, and then discharge 30.0 seconds after charging with a red LED light of 50.0 erg / cm ² to remove the charge, and the potential V _RP 100 msec after the charge removal Measurement was made with a potential measuring probe, which was defined as a residual potential.

  The measurement of the residual potential was performed on the initial photoreceptor and the photoreceptor after the 50,000-sheet image formation, and the increase amount ΔV (V) of the residual potential after the 50,000-sheet image formation was obtained. The results obtained are shown in Table 65.

  As is apparent from the results shown in Table 65, when the electrophotographic photosensitive member of the present invention (Examples 1 to 10) was used, an actual machine running test (50,000 sheets) compared with Comparative Examples 1 to 4 It has been confirmed that the occurrence of image quality defects due to fog, black spots, and ghosting after image formation) can be suppressed, and the increase in residual potential can be reduced. As described above, according to the electrophotographic photosensitive member and the image forming apparatus of the present invention, even if it is repeatedly used, fluctuations in electrical characteristics can be sufficiently suppressed, and occurrence of image quality defects can be sufficiently suppressed. It was confirmed that it was possible.

1 is a schematic cross-sectional view showing a preferred embodiment of an electrophotographic photoreceptor of the present invention. FIG. 5 is a schematic cross-sectional view showing another preferred embodiment of the electrophotographic photosensitive member of the present invention. 1 is a schematic cross-sectional view showing a preferred embodiment of an image forming apparatus of the present invention. It is a schematic cross section which shows other suitable embodiment of the image forming apparatus of this invention. It is a schematic cross section which shows other suitable embodiment of the image forming apparatus of this invention. 1 is a schematic cross-sectional view showing a preferred embodiment of a process cartridge of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Conductive substrate, 2a, 2b ... Undercoat layer, 3a ... High concentration area | region of silane coupling agent, 3b ... Silane coupling agent content layer, 4 ... Photosensitive layer, 5 ... Charge generation layer, 6 ... Charge transport layer , 7 ... protective layer, 8 ... charging means, 9 ... power supply, 10 ... exposure means, 11 ... developing means, 12 ... transfer means, 13 ... cleaning means, 14 ... static eliminator, 15 ... fixing means, 16 ... mounting rail, DESCRIPTION OF SYMBOLS 18 ... Opening part for exposure, 20 ... Transfer object, 30, 100, 110 ... Electrophotographic photoreceptor, 200, 210, 220 ... Image forming apparatus, 300 ... Process cartridge.

Claims (5)

An electrophotographic photosensitive member in which an undercoat layer containing conductive particles and a photosensitive layer are provided in this order on a conductive substrate,
An electrophotographic photoreceptor, wherein a silane coupling agent-containing layer containing a silane coupling agent at a higher concentration than the undercoat layer is provided between the undercoat layer and the photosensitive layer. . An electrophotographic photosensitive member in which an undercoat layer containing conductive particles and a photosensitive layer are provided in this order on a conductive substrate,
An electrophotographic photoreceptor, wherein a silane coupling agent is contained at a higher concentration on the photosensitive layer side of the undercoat layer than on the conductive substrate side of the undercoat layer.   The electrophotographic photosensitive member according to claim 1, wherein the silane coupling agent is a silane coupling agent having an amino group. The electrophotographic photosensitive member according to any one of claims 1 to 3,
A charging means for charging the electrophotographic photosensitive member; a developing means for developing a latent electrostatic image formed on the electrophotographic photosensitive member with toner to form a toner image; and At least one selected from the group consisting of cleaning means for removing toner remaining on the surface;
A process cartridge comprising: The electrophotographic photosensitive member according to any one of claims 1 to 3,
Charging means for charging the electrophotographic photosensitive member;
Exposure means for forming an electrostatic latent image on the charged electrophotographic photosensitive member;
Developing means for developing the electrostatic latent image with toner to form a toner image;
Transfer means for transferring the toner image from the electrophotographic photosensitive member to a transfer target;
An image forming apparatus comprising:

Images