JP2003207919A - Electrophotographic photoreceptor, image forming apparatus and processing unit for image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-performance and high-reliability electrophotographic photoreceptor having high durability and capable of continuously yielding excellent images even in the case of repeated use, and to provide a high-reliability image forming apparatus and a processing unit for the image forming apparatus made compact and realizing high-speed printing by using the electrophotographic photoreceptor. <P>SOLUTION: In the multiplayer electrophotographic photoreceptor successively provided with at least a photoreceptive layer and a protection layer on a conductive supporting body, the protection layer consists of siloxane crosslinked structure obtained by chemically combining structural units having charge transporting performance and includes α-alumina particles whose average particle size is 0.1 to 1.0 μm. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention has high durability,
The present invention also relates to an electrophotographic photosensitive member that achieves high image quality over a long period of time. Further, the present invention relates to an image forming method, an image forming apparatus, and a process unit for the image forming apparatus using the photoconductors.

[0002]

2. Description of the Related Art An electrophotographic method using an electrophotographic photosensitive member which is applied to a copying machine, a facsimile, a laser printer and the like is an image forming method after at least the steps of charging, image exposing and developing the electrophotographic photosensitive member. It is a method consisting of a process of transferring a toner image to a holder (transfer paper), fixing and cleaning the surface of the electrophotographic photosensitive member.

The basic characteristics required of the electrophotographic photosensitive member in this electrophotographic method are that it can be charged to an appropriate potential in a dark place, that the dissipation of electric charge is small in a dark place, and the electric charge can be rapidly applied by light irradiation. It can be dissipated. In addition to these characteristics, long-term reliability such as image quality characteristics, low pollution, and low cost are also required.

Conventionally, as a photoconductor used in the electrophotographic system, a photoconductor having a selenium or selenium alloy as a main component is provided on a conductive support, or an inorganic light such as zinc oxide or cadmium sulfide. Those in which a conductive material is dispersed in a binder, and those using an amorphous silicon-based material are generally known, but in recent years, low cost, high degree of freedom in designing a photoconductor, Organic photoconductors have come to be widely used because of their pollution-free property.

Organic electrophotographic photoreceptors include a photoconductive resin represented by polyvinylcarbazole (PVK), P
VK-TNF (2,4,7-trinitrofluorenone)
Known as a charge transfer complex type, a phthalocyanine-binder-type pigment dispersion type, and a function separation type photoconductor in which a charge generating substance and a charge transporting substance are used in combination. The photoconductor of (1) is excellent in various properties such as sensitivity, durability, and stability, and is attracting attention.

The mechanism of formation of an electrostatic latent image in this function-separated type photoconductor is that when the photoconductor is charged and then irradiated with light, the light passes through a transparent charge transport layer and is caused by a charge generating substance in the charge generating layer. The charge-generating substance that has been absorbed and absorbs light generates charge carriers, which are injected into the charge-transporting layer and move in the charge-transporting layer along the electric field generated by charging, so that the charge on the surface of the photoconductor is removed. By neutralizing, an electrostatic latent image is formed. In the function-separated type photoreceptor, it is known to use a charge transporting substance having a high mobility and having an absorption mainly in the ultraviolet region, and a charge generating substance having a high quantum efficiency and having an absorption mainly in the visible region. And is useful.

However, most of the charge-transporting substances of the organic electrophotographic photosensitive member used in the electrophotographic method have been developed as low molecular weight compounds, and the low molecular weight compounds alone have no film-forming property, and thus are usually inactive. Used by being dispersed and mixed in a polymer. However, the charge transport layer consisting of a low molecular weight charge transport material and an inert polymer is generally soft, and when repeatedly used in the electrophotographic process, film scraping is caused by mechanical load on the surface of the photoreceptor due to the developing system or cleaning system. The disadvantage is that it is easily worn and has low wear resistance. In fact, the abrasion of the film on the photoconductor causes adverse effects such as deterioration of sensitivity and deterioration of chargeability, resulting in a decrease in image density.
An abnormal image such as background stain may be generated and the photoconductor may reach the end of its life.

In recent years, as the image forming apparatus has been downsized, the diameter of the photosensitive member has been reduced, and the high speed of the machine and maintenance-free movement have been added, and the durability of the photosensitive member has been earnestly desired. To increase the durability of the photoconductor, improving the abrasion resistance is the first issue. This technique uses a curable binder in the surface layer (Japanese Patent Laid-Open No. 56-486).
No. 37), an improved binder resin for the photoconductor (JP-A-5-216250), a polymer charge-transporting substance (JP-A 64-1728), and an inorganic filler in the surface layer. And the like (Japanese Patent Application Laid-Open No. 4-281461) and the like. Among these technologies, the one using the curable binder has poor compatibility with the charge transport material and impurities such as the polymerization initiator and unreacted residues increase the potential at the exposed area and cause a decrease in image density. To do. Further, the improved binder resin does not exhibit a remarkable improvement in abrasion resistance due to the composition ratio of the low molecular weight charge transport material. Further, although the one using the polymer type charge transporting substance can improve the abrasion resistance to some extent, its durability is not sufficient, and it is difficult to polymerize and purify the material, and it is difficult to obtain a highly pure substance. Further, there is a problem in production such that the coating liquid has a high viscosity. In addition, although the one in which the inorganic filler is dispersed has an improved average wear resistance, there is a significant difference in wear resistance between the surface exposed inorganic filler and the binder resin portion, and the binder resin portion is selectively scraped deep. It causes unevenness. As a result, defective cleaning of the recess occurs, which causes defects such as image deletion and black streaks. However, as a method of improving such a defect, in JP-A-9-124943 and JP-A-9-190004, a hole-transporting compound is used as a siloxane. It has been proposed to provide a chemically protective surface protection layer in the crosslinked structure. As a result, the rise in the potential of the exposed area due to the curable binder is suppressed, and the strength characteristics and electric characteristics are superior to those of the conventional photoconductor, and attention is paid.

However, the siloxane crosslinkable protective layer photosensitive material having the hole transporting structure bonded thereto also has some drawbacks. As one of them, when a large number of hole transport structures are bonded for the purpose of suppressing the rise of the exposed portion potential, the film strength is lowered and desired abrasion resistance cannot be obtained. On the other hand, a method of containing colloidal silica described in JP-A-2000-275879 has been proposed, but abrasion resistance is improved, but it is generated from a charger or the like due to the influence of the silica surface having an acidic property. Oxidizing gas such as ozone and NOx lowers the resistance of the surface of the photoconductor, resulting in lower resolution and thicker characters. Further, as a countermeasure against this image deterioration, Japanese Patent Laid-Open No.
No. 000-241998 discloses a means for preventing adsorption of oxidizing gas and moisture by providing a photoconductor heating device. This method is effective for preventing image deterioration,
There is a problem that a long warming-up time is required at the time of starting the apparatus, wasteful energy is required during standby, etc., and it cannot be used especially for a small-diameter tandem color machine. Further, Japanese Patent Laid-Open No. 2001-92162 proposes a method of incorporating fine particles having an average particle diameter of 0.05 to 10 μm. However, if the particle diameter is too small, cohesiveness is strong and dispersion is difficult, resulting in abrasion. If unevenness occurs and is too large, incident light is scattered and the smoothness of the surface of the photoconductor deteriorates, resulting in image disturbance. Regarding the material, the desired wear resistance cannot be obtained with the organic fine particles, or the potential of the exposed portion increases. As the one using the metal oxide particles other than silica described in JP-A-2001-255688, tin oxide easily causes image deletion due to conductivity, and colloidal alumina has a remarkable increase in the potential at the exposed portion due to ultrafine particles. However, there are various problems such that desired improvement in wear resistance cannot be obtained, and that titanium oxide causes light scattering due to a difference in refractive index to cause deterioration in resolution. Therefore, the material, shape,
The particle size and properties are very important and affect the durability of the photoconductor.

As described above, a siloxane cross-linking protective layer photoreceptor having a hole transporting structure is still sufficient as a highly durable photoreceptor having stable electric characteristics for a long period of time and capable of providing a good image. It has no performance.

[0011]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a high-performance and highly reliable electrophotographic photosensitive member having high durability and capable of continuously obtaining a good image even after repeated use. To provide. Another object of the present invention is to provide a highly reliable image forming apparatus and a process unit for the image forming apparatus, which are small in size and capable of high-speed printing by using the electrophotographic photosensitive member.

[0012]

As a result of intensive studies, the present inventors have used an electrophotographic photosensitive member having a protective layer, and the protective layer is a siloxane crosslinked structure in which structural units having charge transportability are chemically bonded. And an average particle size of 0.1
By containing 1.0 μm α-alumina particles,
The present invention has been accomplished by discovering that the above object can be achieved.

That is, the average particle size is 0.1 as in the present invention.
An electrophotographic photoreceptor having a charge-transporting siloxane cross-linking protective layer containing .about.1.0 .mu.m .alpha.-alumina particles,
It is possible to provide a highly durable and highly reliable photoconductor having high wear resistance and stable electrical characteristics for a long period of time, and a good image can be provided for a long period of time by a process unit or apparatus using this electrophotoconductor.

That is, the above-mentioned problem is solved by (1) of the present invention.
"In a laminated electrophotographic photoreceptor in which at least a photosensitive layer and a protective layer are sequentially provided on a conductive support, the protective layer is composed of a siloxane cross-linked structure in which structural units having charge transportability are chemically bonded, and has an average particle diameter. 0.1-1.0 μm α-
(2) "The electrophotographic photosensitive member containing alumina particles," (2) "The structural unit in which the protective layer has a charge-transporting property has a triarylamine structure as an element. (1) The electrophotographic photosensitive member according to item (3), (3) "Silicone in the siloxane crosslinked structure of the protective layer has a trivalent bond out of tetravalent bonds, and the remaining 1 The electrophotographic photoconductor according to item (1), which contains 50% or more of those having a substituted or unsubstituted alkyl group or phenyl group whose valence does not participate in crosslinking, with respect to the total silicon. (4) "The content of α-alumina particles in the protective layer is 5% by weight or more and 40% by weight or less with respect to the total amount of the protective layer, and the electrophotographic photosensitive material according to the item (1). Body ", (5)
"The α-alumina particles of the protective layer are transition alumina as a raw material or alumina raw material which becomes transition alumina by heat treatment is fired in an atmosphere gas containing a hydrogen halide gas or an atmosphere gas into which a halogen gas and steam are introduced. The electrophotographic photoconductor according to any one of the items (1) to (4), characterized in that it is manufactured by The first (1), which is produced by thermally decomposing carbonate hydroxide [NH ₄ AlCO ₃ (OH) ₂ ].
The electrophotographic photosensitive member according to any one of the items (4) to (4), (7) "The particle size distribution of the α-alumina particles is 10% cumulative and 90% cumulative from the fine particle side of the cumulative particle size distribution. Any of the above items (1) to (4), characterized in that it is α-alumina showing a particle size distribution with a value of Db / Da of 5 or less when the particle sizes are Da and Db, respectively. 1. The electrophotographic photosensitive member according to 1, wherein (8) “the α-alumina particles have a sodium content of 20 ppm or less as impurities and a purity of 99.95% by weight or more. (1) The electrophotographic photoreceptor according to any one of (1) to (4), (9) "The protective layer contains a polycarboxylic acid compound, and the above (1) is provided. Through (8), the electrophotographic photosensitive member according to any one of (8) to (10) above. The electrophotographic photoreceptor according to any one of (1) to (8) above, wherein the layer contains a hindered amine antioxidant and / or a hindered phenol antioxidant. Achieved by

Further, the above-mentioned subject is (11) of the present invention, "a charging means, an exposing means, and a developing means using the electrophotographic photosensitive member according to any one of (1) to (10) above. And an image forming apparatus having a transfer unit "
Achieved by

Furthermore, the above-mentioned problem is (1) of the present invention.
2) “Using the electrophotographic photosensitive member according to any one of the items (1) to (10), it is selected from the group consisting of a charging unit, a developing unit, a transfer unit, a cleaning unit and a charge eliminating unit. In addition, at least one unit is integrated, and the unit is detachable.

The present invention will be described in detail below. As in the present invention, an electrophotographic photosensitive member having a protective layer is used, and the protective layer is composed of a siloxane crosslinked structure in which structural units having a charge transporting property are chemically bonded and has an average particle size of 0.1 to 1.0 μm. By including α-alumina particles, it is possible to obtain a good image for a long period of time because of high durability and without deterioration of resolution or thickening of characters due to repeated use. It is not clear at present whether the effect will be achieved, but the following reasons are possible.

The siloxane cross-linking protective layer containing no charge transporting structure is disclosed in JP-A-61-1555 and JP-A-61-155.
As described in JP-A-72256, JP-A-1-200366 and JP-A-1-217364, it has high durability, but there is a problem that the potential of the exposed portion rises due to repeated use. . On the other hand, the siloxane cross-linking protective layer in which the charge transport structure was chemically bonded improved the electrical stability by suppressing the rise in the potential at the exposed area, but the introduction of the charge transport structure reduced the strength of the film, resulting in wear due to repeated use. And the desired durability cannot be obtained. As a countermeasure against this, addition of a filler has been proposed, but although this method improves wear resistance, it causes a new problem. As an example of an inorganic filler, when colloidal silica is contained, its surface has an acidic property, and when a conductive filler such as tin oxide is contained, its low resistance makes it possible to oxidize ozone and NOx generated from a charger. Due to gas and environmental fluctuations (high humidity), it is easy to cause resolution degradation and thickening of characters. On the other hand, when the basic titanium oxide is contained, the resolution is not lowered and the characters are not thickened, but the potential of the exposed portion is increased due to the charge trap on the filler surface, and the image density is lowered by repeated use. On the other hand, the present invention uses α-alumina particles having a high insulating property as an inorganic filler, and the above-mentioned image defects do not occur. Also, this α-
Since the alumina particles have an average particle diameter of 0.1 to 1 μm, there is no agglomeration peculiar to the fine particles, and the large and small particles do not cause irregularities on the surface of the photoconductor at the initial stage and the passage of time, so that the toner image is not disturbed. Further, in the present invention, the alumina particles are produced by firing transition alumina as a raw material or an alumina raw material to be transition alumina by heat treatment in an atmosphere gas containing a hydrogen halide gas or in an atmosphere gas containing a halogen gas and steam. And the α-alumina particles are aluminum ammonium carbonate hydroxide [NH ₄ AlCO ₃ (OH)
₂ ] is produced by thermal decomposition of
This effect is remarkably exhibited. That is, the alumina particles produced by such a production method are advantageously used from the following points.

It is possible to easily produce a well-balanced α-alumina having an average particle size of 0.1 to 1 μm, which has both mechanical properties and electrical properties. The other manufacturing method, the crushing method, is suitable for larger particle diameters, and the flame generation method of 0.05 μm or more is difficult. Since the particle size distribution is very sharp, the particle sizes are uniform, and the particles have a nearly spherical polyhedral shape, image defects due to uneven wear and blade damage do not occur. The α-alumina produced by the pulverization method has a wide particle size distribution and contains a large amount of fine powder, so uneven wear is likely to occur, and it has a sharp crushed surface and contains large particles. Breakage often occurs. The particles have a weak cohesive property and become almost single particles, which facilitates dispersion during preparation of the coating liquid. It is possible to produce high-purity α-alumina, and the content of sodium that raises the potential of the exposed area is very small. Since the inside of the grain is homogeneous and voids and grain boundaries that cause light scattering do not exist inside the grain, the straightness of incident light is high and a latent image corresponding to the exposure spot can be obtained.

Further, in the present invention, a crosslinked siloxane having a charge transporting structure is used as a binder for holding α-alumina, but this improves the strength as compared with the thermoplastic binder resin, and the exposed filler portion and the binder portion are Irregularities due to wear over time are reduced. In addition, the charge transport structure in the crosslinked siloxane is important for stabilizing the electric characteristics by repeated use, and the triphenylamine structure having a high hole mobility is particularly effective.

Further, in the present invention, it is effective that the protective layer contains a polycarboxylic acid compound. This polycarboxylic acid compound is added for the purpose of improving the dispersibility of the α-alumina particles in the siloxane cross-linking protective layer or in its coating liquid, and is effective in suppressing damage to the photoreceptor. In addition, an antioxidant is added to the protective layer for the purpose of suppressing decomposition by ozone, NOx, etc. Among them, a hindered amine-based antioxidant,
Hindered phenolic antioxidants are useful in terms of efficacy and side effects.

Next, the protective layer, which is the main component of the present invention, will be described in detail. The siloxane cross-linking protective layer in which the charge transporting structure of the present invention is chemically bonded is disclosed in JP-A-9-124943.
Japanese Patent Laid-Open No. 9-19000, Japanese Patent Laid-Open No. 2000-
It is formed by a known method as described in Japanese Patent No. 171990 and Japanese Patent Laid-Open No. 2000-275877. That is, it is basically formed by reacting an organic silane compound having a hydrolyzable group with a compound having a charge transporting structural unit chemically bonded to the organic silane compound and causing a curing reaction by an acid, a base or heating. It

The organosilane compound having a hydrolyzable group used here will be described. Examples of the hydrolyzable group include a hydroxyl group, an alkoxy group, a methylethylketoxime group, a diethylamino group, an acetoxy group and a halogen. Of these, hydroxyl groups, methoxy groups, ethoxy groups, propoxy groups, butoxy groups, etc., having 1 to 6 carbon atoms.
Alkoxy groups are preferred. This hydrolyzable group can be used by mixing one to four, and a compound having one functional group acts in the direction of stopping the polymerization reaction, and two or more of them promote the polymerization reaction, In particular, compounds having 3 and 4 functional groups accelerate the crosslinking reaction. When a compound having four functional groups is used as a main component, the protective layer becomes hard but loses flexibility and becomes brittle. Further, since the reaction rapidly progresses, there is a problem that the pot life of the coating liquid is short and liquid management is difficult.
On the contrary, if a compound having two or one functional groups is used as a main component, it may be impossible to form the protective layer. For this reason,
In order to impart hardness and flexibility to the protective layer, it is preferable to use a silane compound having three functional groups as a main component, that is, 50% by weight or more of the whole organosilane compound having a hydrolyzable group. As the substituent other than the hydrolyzable group, a methyl group,
An alkyl group such as an ethyl group, a propyl group and a butyl group, and an aryl group such as a phenyl group, a naphthyl group and a biphenyl group are preferable, and this substituent may further have an alkyl group and a halogen atom. When there are plural substituents, they may be the same or different. As a typical organosilane compound having a hydrolyzable group, tetramethoxysilane,
Methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, tetraethoxysilane, ethyltrimethoxysilane, diethyldimethoxysilane, triethylmethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, methylphenyldimethoxysilane, Examples thereof include vinyltrimethoxysilane. The organosilane compound having a hydrolyzable group may be an oligomer or polymer which has been previously hydrolyzed under acidic or basic conditions, and a crosslinked structure may be formed by a dehydration condensation reaction after coating.

As the charge-transporting structure which is held in the siloxane cross-linking protective layer by a chemical bond, a general charge-transporting compound structure is used. Examples of the electron transporting structure include chloranil, bromanyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7.
-Trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro -4H-indeno [1,2-b] thiophen-4-one, 1,3,7-trinitrodibenzothiophene-5,5-dioxide,
Examples thereof include electron-accepting structures such as diphenoquinone derivatives, phthalic anhydride derivatives, and maleic anhydride derivatives. Examples of the hole transporting structure include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, and triarylamine derivatives. Examples thereof include electron donating structures such as a reel methane derivative, a 9-styrylanthracene derivative, a pyrazoline derivative, a divinylbenzene derivative, a hydrazone derivative, an indene derivative, a butadiene derivative and a pyrene derivative, and a bisstilbene derivative and an enamine derivative. Among them, the triarylamine structure is useful as the charge transporting structure because it has a high charge transfer ability. The charge-transporting structure has one or more functional groups such as a hydroxyl group, a mercapto group, an amino group, and an alkoxysilyl group, and the organic silicon compound has a chemical structure in the crosslinked structure during hydrolysis reaction and dehydration condensation reaction. Incorporated by binding. This functional group is bonded to the charge transport structure directly or via a linking group, and examples of the linking group include an alkylene group such as a methylene group and an ethylene group, and an arylene group such as a phenylene group. When there is one functional group bonded to the charge transporting structure, it is bonded as a pendant group in the siloxane crosslinked structure, and when there are two or more functional groups, it is incorporated into the structure as a crosslink group. Two or more kinds of the charge transporting compound having this functional group can be used at the same time. The content of the charge transport compound having a functional group used here is 20 to 150 parts by weight, preferably 30 to 10 parts by weight based on 100 parts by weight of the theoretical content of the organosilicon compound having a hydrolyzable group after crosslinking.
0 parts by weight. If it is less than 20 parts by weight, the charge transporting property will be insufficient and the potential of the exposed area will increase with repeated use. Also,
If it exceeds 150 parts by weight, the strength of the protective layer is lowered and the wear resistance is significantly deteriorated.

The protective layer of the present invention contains α-alumina particles having an average particle diameter of 0.1 to 1 μm for the purpose of obtaining higher wear resistance. As the α-alumina particles of the present invention, those produced by a general production method such as a Bayer method or a hydrothermal synthesis method can be used, but in particular, the following production is performed in terms of ease of production, sharp particle size distribution, high purity, etc. Α created by the method
-Alumina particles are effective. Examples of the α-alumina particles include JP-A-6-191833 and JP-A-7-2.
Manufactured by firing transition alumina as the raw material described in JP-A-06430 or an alumina raw material to be transition alumina by heat treatment in an atmosphere gas containing a hydrogen halide gas or in an atmosphere gas into which a halogen gas and steam are introduced. Japanese Patent Publication No. 6-17224,
Aluminum ammonium carbonate hydroxide [NH ₄ Al described in Japanese Patent No. 2983042]
Examples include those produced by thermally decomposing CO ₃ (OH) ₂ ] and those produced by hydrolysis of aluminum alkoxide. The α-alumina particles obtained by such a production method have a sharp particle size distribution, and have a cumulative particle size of 10% from the fine particle side and a cumulative particle size of 90%, respectively.
When a and Db are set, the value of Db / Da is 5 or less. Further, the impurity has a high sodium content of 20 ppm or less and a high purity of 99.95% or more. Furthermore, by these production methods, particles having no voids or grain boundaries inside and homogeneous and low in agglomeration between particles, and having an average particle diameter of 0.1 to 0.1
1 μm α-alumina particles are easily manufactured. The cumulative particle size distribution used here is a value of a cumulative volume ratio obtained by a laser scattering method, and as a measuring device, for example, a dynamic light scattering device DLS-700 (manufactured by Otsuka Electronics) can be used. The value of the cumulative volume ratio of 50% is used as the average particle diameter.

In the present invention, other inorganic fillers may be used together with the above α-alumina particles, if necessary. In the present invention, the photoreceptor characteristics can be adjusted by mixing other inorganic fillers in addition to the α-alumina particles. For example, by mixing conductive particles,
The potential of the exposed portion can be lowered, and by mixing particles having a high light-transmitting property, it is possible to prevent scattering of irradiation light and improve the sharpness of the latent image. However, depending on the process conditions, or by mixing a large amount,
On the contrary, caution should be exercised because adverse effects such as deterioration of charging property, image deletion, and background image stain may occur. As the inorganic filler, copper, tin, aluminum, metal powder such as indium, silica, tin oxide, zinc oxide, titanium oxide, zirconium oxide, indium oxide, antimony oxide, bismuth oxide, calcium oxide, tin oxide doped with antimony. Examples thereof include particles of a metal oxide such as tin-doped indium oxide, a metal fluoride such as tin fluoride, calcium fluoride, and aluminum fluoride, potassium titanate, and boron nitride. Further, these inorganic fillers including α-alumina particles can be subjected to a surface treatment for the purpose of improving dispersibility and the like, and as the surface treatment agent used at this time, a titanate coupling agent or an aluminum coupling agent is used. Agent, zircoaluminate coupling agent, higher fatty acid, silane coupling agent, A
Examples include l ₂ O ₃ , TiO ₂ , ZrO ₂ , silicone, aluminum stearate, and a mixture treatment thereof.

The ratio of the α-alumina particles contained in the protective layer depends on the desired wear resistance, the particle size of the α-alumina particles,
Depending on various factors such as the image forming process used, 1 to 7 relative to the total weight of the siloxane cross-linking protective layer of the present invention.
It is 0% by weight, preferably 5 to 50% by weight. When the content of α-alumina particles is less than 1% by weight, the strength of the siloxane cross-linking protective layer having a charge transporting structure is not improved, and when it is 70% by weight or more, the straightness of light and stabilization of electrical characteristics are problematic. Occurs. It is usefully used within a content range of 5 to 50% by weight.

The protective layer containing α-alumina particles is prepared by, for example, combining the α-alumina particles with an organic solvent in a ball mill,
After being dispersed using a conventional method such as an attritor, a sand mill, a bead mill, or an ultrasonic wave, the dispersion is at least an organosiloxane compound having a hydrolyzable group or / and a reactive siloxane oligomer or polymer obtained by polymerizing the organosiloxane compound. , A charge transporting compound having a functional group, in addition to a coating solution containing an acid or base polymerization catalyst,
Is applied. In some cases, the α-alumina particles may be dispersed in a solution containing the above-mentioned hydrolyzable group-containing organosiloxane compound to prepare a coating solution. A cross-linking protective layer can be obtained by allowing the curing reaction to proceed by heating after coating.

Examples of the solvent for dispersing the α-alumina particles include ketones such as cyclohexanone and 2-butanone, alcohols such as methanol, ethanol and butanol, cellzolobes such as methylcellzolob and ethylcellzolob, ethyl acetate and butyl acetate. Various solvents such as the above-mentioned esters can be used, and two or more kinds of solvents may be mixed and used.

A dispersant is optionally added during the dispersion of the α-alumina particles or in the coating liquid for the purpose of improving dispersibility and stability of the coating liquid. This dispersant is α
The polycarboxylic acid compound is particularly effective in that it disperses the alumina particles to a value close to the primary particle size and does not adversely affect the electrical characteristics and image characteristics. The polycarboxylic acid compound refers to low molecular weight compounds, oligomers, and high molecular weight compounds having a plurality of carboxylic acid residues, and examples thereof include organic fatty acids and highly oxidized resins. Examples of the oligomer or polymer compound of the polycarboxylic acid compound include polyester resins, acrylic resins, copolymers using acrylic acid and methacrylic acid, and styrene-acrylic copolymers. As the acid value of the polycarboxylic acid compound used here, one having an acid value of 10 to 400 (mgKOH / g) can be effectively used. (The acid value is defined as the number of milligrams of potassium hydroxide required to neutralize the free fatty acid contained in 1 g.) The amount of the polycarboxylic acid compound added is 100 α-alumina particles contained. 0.01 to 50 parts by weight, preferably 0.1 to 20 parts by weight
Parts by weight.

Further, an antioxidant is contained in the above-mentioned coating liquid, if necessary, for the purpose of preventing deterioration of the protective layer due to an oxidizing gas. Known antioxidants such as phenol-based antioxidants, amine-based antioxidants, hydroquinone-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants can be used as the antioxidant, but especially hindered amine-based antioxidants can be used. Agents and hindered phenolic antioxidants are effective in terms of efficacy and side effects. Commercially available hindered amine antioxidants include Sanol LS2626 and Sanol LS76.
5, Sanol LS770, Sanol LS744, Tinuvin 144, Tinuvin 622LD, Mark LA57, Mark LA67, Mark LA62, Mark LA68, Mark LA63, Sumisorp 577 and the like. Moreover, as a hindered phenolic antioxidant, Iganox 1076, Iganox 1035, Iganox 10
81, iganotux 1222, iganotux 1010,
Iganox 1098, Iganox 245, Iganox 1330, Iganox 3114, Sumilizer B
P-101, Sumilizer BP-76, Sumilizer G
M, Sumilizer GA-80, Sumilizer BBM-
S, Sumilizer WX-R, Sumilizer BHT, Sanol LS2626, Sumisorp 400 and the like.
The content of the above-mentioned antioxidant is 0.1 to 30 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the theoretical content of the organosilicon compound having a hydrolyzable group after crosslinking. You may use together the above.

The protective layer coating solution of the present invention is used for the purpose of accelerating the cross-linking reaction, if necessary, and alkyl titanate organic acid salts such as dibutyltin diacetate, dibutyltin dilaurate and dibutyltin octoate, and titanic acid esters such as butyl titanate. For curing, represented by alkali metal salts of organic carboxylic acids, nitrous acid, sulfurous acid, aluminic acid, carbonic acid, thiocyanic acid, organic amine salts such as tetramethylammonium acetate, octenoic acid of aluminum and zinc, acetylacetone complex compounds, etc. A catalyst can be used. Also,
If necessary, a leveling agent such as dimethyl silicone oil or methylphenyl silicone oil can be added.

As the solvent used in the coating liquid of the present invention, an organic siloxane compound having the hydrolyzable group or / and a reactive siloxane oligomer or polymer obtained by polymerizing the organic siloxane compound, a reaction having a charge transporting structure A solvent that dissolves the volatile compound well is preferable,
The solvent used to disperse the α-alumina particles can be used.

As a method for coating the protective layer, a known method can be used, and a dip coating method, a spray coating method, a bead coating method, a ring coating method or the like can be used. The curing conditions are preferably heating at 100 to 200 ° C. If the temperature is less than 100 ° C., the curing reaction takes a long time, and therefore unreacted hydrolyzable groups may be present. 200
If the temperature exceeds ℃, the hole-transporting group is likely to be oxidized and deteriorated, and the electrical characteristics and the like are likely to be adversely affected. More preferably, it is used after being heated and cured at 120 to 160 ° C. The time required for curing is 10 minutes to 5 hours, usually 2 in terms of productivity.
Done in less than an hour.

The film thickness of the siloxane cross-linking protective layer of the present invention is
It is 0.5 to 10 μm, preferably 1 to 7 μm.

[Structure and Elements] <Structure of Electrophotographic Photosensitive Member> The electrophotographic photosensitive member used in the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an electrophotographic photosensitive member of the present invention, in which a photosensitive layer (33) containing a charge generating substance and a binder resin as main components is formed on a conductive support (31). Α-on top
Crosslinked siloxane protective layer containing alumina particles (39)
Is provided. In the structure shown in FIG. 2, a charge generating layer (35) containing a charge generating substance as a main component and a charge transporting layer (37) containing a charge transporting substance as a main component are formed on a conductive support (31). In the laminated structure, a crosslinked siloxane protective layer (39) containing α-alumina particles is provided on the charge transport layer (37). FIG. 3 shows a structure in which a charge transport layer (37) containing a charge transport substance as a main component and a charge generating layer (35) containing a charge generating substance as a main component are laminated on a conductive support (31). The crosslinked siloxane protective layer (39) containing α-alumina particles is provided on the charge generation layer (35).

<Regarding Conductive Support> The conductive support (31) has conductivity of 10 ¹⁰ Ω · cm or less in volume resistance, for example, aluminum, nickel, chromium, nichrome, copper, gold, silver. , Metal such as platinum, metal oxide such as tin oxide and indium oxide, coated on film or cylindrical plastic or paper by vapor deposition or sputtering, or plate of aluminum, aluminum alloy, nickel, stainless steel, etc. Further, it is possible to use a tube or the like which has been subjected to a surface treatment such as cutting, superfinishing, polishing or the like after forming them into a raw tube by a method such as extrusion or drawing. In addition, JP-A-52-36
No. 016 publication, an endless nickel belt,
An endless stainless belt can also be used as the conductive support (31). In addition, a conductive powder dispersed in a suitable binder resin and coated on the above support can also be used as the conductive support (31) of the present invention.

As the conductive powder, carbon black, acetylene black, metal powder of aluminum, nickel, iron, nichrome, copper, zinc, silver or the like, or metal oxide powder of conductive tin oxide, ITO or the like is used. And so on. Further, the binder resin used at the same time, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer , Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal,
Polyvinyltoluene, poly-N-vinylcarbazole,
Examples thereof include thermoplastic, thermosetting resin or photocurable resin such as acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, and alkyd resin. Such a conductive layer can be provided by dispersing these conductive powders and a binder resin in a suitable solvent, for example, tetrahydrofuran, dichloromethane, methyl ethyl ketone, toluene or the like and applying the dispersion.

Further, the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, and polytetrafluoroethylene-based fluororesin on a suitable cylindrical substrate. Those provided with a conductive layer by a heat shrinkable tube can also be favorably used as the conductive support (31) of the present invention.

<Regarding the Photosensitive Layer> Next, the photosensitive layer will be described. The photosensitive layer may have a laminated structure or a single layer structure. In the case of a laminated structure, the photosensitive layer is composed of a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance. In the case of a single layer structure, the photosensitive layer is composed of at least a layer containing a charge generating substance. Each of the photosensitive layer having a laminated structure and the photosensitive layer having a single layer structure will be described below.

<Photosensitive Layer Comprised of Plural Layers> Charge Generating Layer The charge generating layer (35) is a layer containing a charge generating substance as a main component, and a binder resin may be used together if necessary. An inorganic material and an organic material can be used as the charge generating substance.

Examples of the inorganic material include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compounds, and amorphous silicon. As amorphous silicon, dangling bonds terminated with hydrogen atoms or halogen atoms, or those doped with boron atoms, phosphorus atoms, etc. are preferably used.

On the other hand, a known material can be used as the organic material. For example, phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, azurenium salt pigment, squaric acid methine pigment, azo pigment having a carbazole skeleton, azo pigment having a triphenylamine skeleton, azo pigment having a diphenylamine skeleton, dibenzothiophene skeleton Having azo pigment, azo pigment having fluorenone skeleton, azo pigment having oxadiazole skeleton, azo pigment having bisstilbene skeleton, azo pigment having distyryl oxadiazole skeleton, azo pigment having distyryl carbazole skeleton, perylene Series pigments, anthraquinone series or polycyclic quinone series pigments, quinone imine series pigments, diphenylmethane and triphenylmethane series pigments, benzoquinone and naphthoquinone series pigments, cyanine and azomethine series dyes, Goido pigments, bisbenzimidazo - such as Le based pigments. These charge generating substances can be used alone or as a mixture of two or more kinds.

As the binder resin used in the charge generation layer (35) as required, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral,
Examples thereof include polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, polyacrylamide and the like. These binder resins can be used alone or as a mixture of two or more kinds. Further, as a binder resin for the charge generation layer, in addition to the binder resin described above, a polymer charge transport material (for example, JP-A-64-1
No. 728, No. 64-13061, No. 64-19049, No. 4-11627, No. 4-225014, No. 4-230.
No. 767, No. 4-320420, No. 5-232727, No. 6-234838, No. 6-234839, No. 6-295.
077, JP 7-56374, JP 7
-325409, JP-A-9-80772,
JP-A-9-80783, JP-A-9-80784, JP-A-9-127713, and JP-A-9-21
1877, JP 9-222740 A, JP 9-265197 A, JP 9-265201 A, JP 9-297419 A, JP 9-30 A.
No. 4956). Among these polymer charge transport materials, polycarbonate having a triarylamine structure in its main chain and / or side chain is effective. The amount of the binder resin used in the charge generation layer (35) is 0 to 500 with respect to 100 parts by weight of the charge generation material.
Suitable is parts by weight, preferably 0 to 200 parts by weight. Furthermore, a low molecular weight charge transport material may be added if necessary.

The low molecular weight charge transport materials that can be used in combination with the charge generation layer (35) include hole transport materials and electron transport materials. Examples of the electron transport material include chloranil, bromanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, and 2,4. , 5,7-Tetranitroxanthone, 2,
4,8-Trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophene-4
-One, 1,3,7-trinitrodibenzothiophene-
Examples thereof include electron accepting substances such as 5,5-dioxide and diphenoquinone derivatives. These electron transport materials are
They can be used alone or as a mixture of two or more.

Examples of the hole-transporting substance include the electron-donating substances shown below, which are preferably used. Examples of the hole transport material include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triaryls. Other known materials such as a methane derivative, a 9-styrylanthracene derivative, a pyrazoline derivative, a divinylbenzene derivative, a hydrazone derivative, an indene derivative, a butadiene derivative, a pyrene derivative, a bisstilbene derivative, an enamine derivative, and the like can be given. These hole transport materials can be used alone or as a mixture of two or more kinds. The amount of the low molecular weight charge transport material used in the charge generation layer (35) is 0 to 100 parts by weight of the charge generation material.
500 parts by weight, preferably 0 to 300 parts by weight are suitable.

The method for forming the charge generation layer (35) includes
The vacuum thin film forming method and the casting method from a solution dispersion system are largely cited. As the former method, a vacuum vapor deposition method, a glow discharge decomposition method, an ion plating method, a sputtering method, a reactive sputtering method, a CVD method, or the like is used, and the above-mentioned inorganic material and organic material can be favorably formed.

In order to form a charge generation layer by the casting method described later, the above-mentioned inorganic or organic charge generation material may be used together with a binder resin if necessary tetrahydrofuran, dioxane, dioxolane, toluene,
Disperse with a ball mill, attritor, sand mill, bead mill, etc. using a solvent such as dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, cyclopentanone, anisole, xylene, methyl ethyl ketone, acetone, ethyl acetate, butyl acetate, etc., and disperse the dispersion appropriately. It can be formed by diluting and applying.
Further, if necessary, a leveling agent such as dimethyl silicone oil or methylphenyl silicone oil can be added. The coating can be carried out using a dip coating method, a spray coating method, a bead coating method, a ring coating method, or the like.

The thickness of the charge generation layer provided as described above is suitably about 0.01 to 5 μm, preferably 0.05 to 2 μm.

Charge Transport Layer The charge transport layer (37) can be formed by dissolving or dispersing a charge transport substance and a binder resin in a suitable solvent, applying the solution on the charge generating layer (35) and drying.
As the charge transport material, the electron transport material, hole transport material and polymer charge transport material described in the charge generation layer (35) can be used. As the binder resin, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinyl Vinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal,
Polyvinyltoluene, poly-N-vinylcarbazole,
Examples thereof include thermoplastic or thermosetting resins such as acrylic resins, silicone resins, epoxy resins, melamine resins, urethane resins, phenol resins, and alkyd resins.

The amount of charge transport material is 100% of binder resin.
20 to 300 parts by weight, preferably 40 to 300 parts by weight
150 parts by weight is suitable. However, when the polymer charge transport material is used, it can be used alone or in combination with a binder resin.

As the solvent used for coating the charge transport layer (37), the same solvents as those for the charge generation layer can be used, but those capable of dissolving the charge transport substance and the binder resin well are suitable. Even if these solvents are used alone, 2
You may use it in mixture of 2 or more types. In addition, the charge transport layer (3
The coating method similar to that of the charge generation layer (35) can be used for forming 7).

If necessary, a plasticizer and a leveling agent may be added. As the plasticizer that can be used in combination with the charge transport layer (37), those used as plasticizers for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount thereof is 100 parts by weight of the binder resin. 0 to 30 parts by weight is suitable. As the leveling agent that can be used in combination with the charge transport layer (37), silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain are used. About 0 to 1 part by weight is suitable for 100 parts by weight of the binder resin. The thickness of the charge transport layer (37) is preferably about 5 to 50 μm, and is preferably about 10 to 40 μm in view of image characteristics such as resolution and background stain and electric characteristics such as charging potential and sensitivity.

<Photosensitive Layer Having Single Layer> Next, the case where the photosensitive layer has a single layer structure will be described. In the single-layer structure, a photosensitive layer (33) in which at least a charge generating substance is dispersed in a binder resin is provided on a conductive support. Photosensitive layer (3
3) can be formed by dissolving or dispersing, in addition to the charge-generating substance and the binder resin, a charge-transporting substance in a suitable solvent, and applying and drying this. If necessary, a plasticizer, a leveling agent, etc. may be added. The charge generating material, the charge transporting material, the plasticizer, and the leveling agent are the charge generating layer (35) and the charge transporting layer (3), respectively.
The same as described above for 7) can be used.

As the binder resin, in addition to the binder resins already mentioned in the charge transport layer (37), the binder resins mentioned in the charge generation layer (35) may be mixed and used. Further, the above-mentioned polymer charge transport materials can also be used favorably. The amount of the charge generating substance is preferably 1 to 40 parts by weight, and the amount of the charge transporting substance is 0, relative to 100 parts by weight of the resin component.
To 190 parts by weight is preferable, and more preferably 50 to 1
It is 50 parts by weight. The photosensitive layer is a charge-generating substance, a binder resin together with a charge-transporting substance, if necessary, tetrahydrofuran, dioxane, dichloroethane, a coating liquid dispersed by a disperser using a solvent such as cyclohexane, a dip coating method or spray coating, It can be formed by coating with a bead coat, a ring coat, or the like. The thickness of the photosensitive layer is 5 to 25
About μm is appropriate.

<Undercoat Layer> In the photoreceptor of the present invention, an undercoat layer can be provided between the conductive support (31) and the photosensitive layer. The subbing layer generally contains a resin as a main component, but considering that the photosensitive layer is coated on the resin with a solvent, the resin may be a resin having high solvent resistance to a general organic solvent. desirable. Such resins include polyvinyl alcohol, casein, water-soluble resins such as sodium polyacrylate, copolymer nylon, alcohol-soluble resins such as methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, epoxy. Examples of the resin include curable resins that form a three-dimensional network structure, such as resins. In addition, the undercoat layer contains titanium oxide to prevent moire and reduce residual potential.
Fine powder pigments of metal oxides such as silica, alumina, zirconium oxide, tin oxide and indium oxide may be added.

These undercoat layers can be formed by using an appropriate solvent and coating method as in the above-mentioned photosensitive layer.
Further, as the undercoat layer of the present invention, a silane coupling agent,
A titanium coupling agent, a chromium coupling agent, etc. can also be used. In addition to the above, the undercoat layer of the present invention includes A
l ₂ O ₃ provided by anodic oxidation, organic substances such as polyparaxylylene (parylene), SiO ₂ , SnO ₂ , and T
An inorganic substance such as iO ₂ , ITO or CeO ₂ provided by a vacuum thin film forming method can also be favorably used. Besides these, known ones can be used. The thickness of the undercoat layer is 0 to 5
μm is suitable.

<Intermediate Layer> In the photoreceptor of the present invention, it is possible to provide an intermediate layer between the photosensitive layer (33) and the protective layer (39). A binder resin is generally used as a main component in the intermediate layer. As these resins,
Examples thereof include polyamide, alcohol-soluble nylon, water-soluble polyvinyl butyral, polyvinyl butyral, polyvinyl alcohol and the like. As a method of forming the intermediate layer,
As described above, a general coating method can be adopted. The thickness of the intermediate layer is preferably about 0.05 to 2 μm.

<Regarding Addition of Antioxidant> Further, in the present invention, for the purpose of improving environment resistance, in particular, for the purpose of preventing a decrease in sensitivity and an increase in residual potential, a hindered amine-based antioxidant is particularly added to the protective layer. And hindered phenolic antioxidants are effectively used, but antioxidants are also added to other layers such as the charge generation layer, charge transport layer, undercoat layer and intermediate layer for the same purpose. be able to. The following may be mentioned as antioxidants that can be used in the present invention.

Phenolic compounds 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3,5-di) -T-
Butyl-4-hydroxyphenyl) propionate,
2,2'-methylene-bis- (4-methyl-6-t-butylphenol), 2,2'-methylene-bis- (4-
Ethyl-6-t-butylphenol), 4,4'-thiobis- (3-methyl-6-t-butylphenol),
4,4'-butylidene bis- (3-methyl-6-t-butylphenol), 1,1,3-tris- (2-methyl-4-hydroxy-5-t-butylphenyl) butane,
1,3,5-Trimethyl-2,4,6-tris (3,5
-Di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ', 5'-di-
t-butyl-4'-hydroxyphenyl) propionate] methane, bis [3,3'-bis (4'-hydroxy-3'-t-butylphenyl) butyric acid] glycol ester, tocopherols and the like.

Para-phenylenediamines N-phenyl-N'-isopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-
Phenylenediamine, N, N'-di-isopropyl-p
-Phenylenediamine, N, N'-dimethyl-N, N '
-Di-t-butyl-p-phenylenediamine and the like.

Hydroquinones 2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t
-Octyl-5-methylhydroquinone, 2- (2-octadecenyl) -5-methylhydroquinone and the like.

Organic sulfur compounds dilauryl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, ditetradecyl-3,3'-thiodipropionate and the like.

Organic Phosphorus Compounds Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine and the like.

These compounds are known as antioxidants for rubbers, plastics, fats and oils, and commercially available products are easily available. The addition amount of the antioxidant in the present invention is 0.01 to 10% by weight based on the total weight of the layer to be added.
Is.

<Regarding Image Forming Method and Image Forming Apparatus> Next, the image forming method and the image forming apparatus of the present invention will be described in detail with reference to the drawings. The image forming method and the image forming apparatus of the present invention mean that the charge transporting structure of the present invention is chemically bonded to the siloxane cross-linking protective layer having an average particle size of 0.1 to 0.1.
A photoreceptor containing 1.0 μm α-alumina particles is used, and for example, after at least the photoreceptor is subjected to charging, image exposure, and development processes, transfer, fixing, and exposure of a toner image to an image carrier (transfer paper). The image forming method and the image forming apparatus are formed by a process of cleaning the body surface.
In some cases, an image forming method or the like in which an electrostatic latent image is directly transferred to a transfer body and developed, does not necessarily have the above-described process of disposing on a photoreceptor.

FIG. 4 is a schematic view showing an example of the image forming apparatus. A charging charger (3) is used as a means for uniformly charging the photoconductor. As the charging means, a corotron device, a scorotron device, a solid-state discharge element, a needle electrode device, a roller charging device, a conductive brush device, etc. are used, and all known methods can be used. Next, the image exposure unit (5) is used to form an electrostatic latent image on the uniformly charged photoreceptor.
This light source includes a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, and a light emitting diode (LE
D), semiconductor lasers (LD), electroluminescence (EL) and the like can be used in general.
Further, various filters such as a sharp cut filter, a bandpass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range.

Next, the developing unit (6) is used to visualize the electrostatic latent image formed on the photoreceptor. As a developing method, there are a one-component developing method using a dry toner, a two-component developing method, and a wet developing method using a wet toner. When the photoreceptor is positively (negatively) charged and imagewise exposed, a positive (negative) electrostatic latent image is formed on the surface of the photoreceptor. If this is developed with a toner of negative (positive) polarity (electrodetection fine particles), a positive image is obtained, and if it is developed with a toner of positive (negative) polarity, a negative image is obtained.

Next, the transfer charger (10) is used to transfer the toner image visualized on the photoconductor onto the transfer body. In addition, a pre-transfer charger (7) may be used for better transfer. As these transfer means, an electrostatic transfer method using a transfer charger, a bias roller, a mechanical transfer method such as an adhesive transfer method, a pressure transfer method, or a magnetic transfer method can be used. As the electrostatic transfer method, the charging means can be used.

Next, a separation charger (11) and a separation claw (12) are used as means for separating the transfer member from the photosensitive member. As other separating means, electrostatic attraction induction separation, side end belt separation, tip grip conveyance, curvature separation, etc. are used. The charging means can be used as the separation charger.

Next, a fur brush (14) and a cleaning blade (15) are used to clean the toner remaining on the photoconductor after transfer. In addition, the pre-cleaning charger (13) may be used to perform the cleaning more efficiently. As other cleaning means, there are a web method, a magnet brush method and the like, but each may be used alone or in combination with a plurality of methods.

Next, a charge eliminating means is used for the purpose of removing the latent image on the photosensitive member, if necessary. A charge eliminating lamp (2) and a charge eliminating charger are used as the charge eliminating means, and the exposure light source and the charging means can be used, respectively. In addition, all known processes such as document reading, paper feeding, fixing, and paper discharging that are not close to the photoconductor can be used. The present invention is an image forming method and an image forming apparatus using the electrophotographic photosensitive member according to the present invention for such image forming means.

<Regarding Process Unit for Image Forming Apparatus> The image forming means may be fixedly incorporated in a copying machine, a facsimile machine, or a printer. It may be free. FIG. 5 is a schematic view showing an example of a process unit for an image forming apparatus.

A process unit for an image forming apparatus is a device (component) in which a photoconductor is built in and at least one of a charging unit, a developing unit, a transfer unit, a cleaning unit, and a charge removing unit is integrated and which is detachable. Is. The present invention relates to at least a photoconductor containing an α-alumina particle having an average particle size of 0.1 to 1.0 μm in a siloxane cross-linking protective layer having a charge-transporting structure chemically bonded, and at least charging, developing, transferring, cleaning and neutralizing means. It is intended to provide a process unit for an image forming apparatus, which is integrated with each other.

[0075]

EXAMPLES Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples. All parts used in the examples are parts by weight.

Example 1 An undercoat layer coating liquid, a charge generating layer coating liquid, and a charge transport layer coating liquid having the following compositions were successively coated and dried on an φ30 mm aluminum drum. An undercoat layer of 3.5 μm, a charge generation layer of 0.2 μm, and a charge transport layer of 22 μm were formed. The cross-linking protective layer is an organic silane compound having a hydrolyzable group having the following composition, acid /
Base, a charge transporting compound having a functional group, α-alumina particles, an antioxidant if necessary, a dispersant if necessary,
A coating liquid composed of a curing agent and a solvent was ring-coated on the charge transport layer, and heat-cured at 140 ° C. for 40 minutes to provide a cross-linked film thickness of 3 μm. In addition, the α-alumina particles were added with a solvent and, if necessary, a ball mill dispersed for 24 hours together with a dispersant. Thus, the electrophotographic photosensitive member of the present invention was obtained.

[0077] [Coating liquid for undercoat layer]   Alkyd resin 6 parts     (Beckosol 1307-60-EL, manufactured by Dainippon Ink and Chemicals)   Melamine resin 4 parts     (Super Beckamine G-821-60, manufactured by Dainippon Ink and Chemicals)   Titanium oxide 40 parts   Methyl ethyl ketone 50 parts

[0078] [Coating liquid for charge generation layer]   2.5 parts of bisazo pigment with the following structure

[0079]

[Chemical 1] Polyvinyl butyral (XYHL, UCC) 0.5 part Cyclohexanone 200 parts Methyl ethyl ketone 80 parts

[0080] [Coating liquid for charge transport layer]   Bisphenol Z polycarbonate     (Panlite TS-2050, manufactured by Teijin Kasei) 10 parts   7 parts of a low molecular weight charge transport material (D-1) having the following structure

[0081]

[Chemical 2] Tetrahydrofuran 100 parts 1% silicone oil 1 part (KF50-100CS, Shin-Etsu Chemical Co., Ltd.) tetrahydrofuran solution

[0082] [Crosslinked siloxane protective layer coating liquid]   Organosilane compound having a hydrolyzable group     Methyltrimethoxysilane 100 parts   Acid / base 3% acetic acid 20 parts   35 parts of a charge transporting compound HT-1 having a functional group

[0083]

[Chemical 3] α-Alumina particles Sumicorundum AA-03: Sumitomo Chemical Co., Ltd. 15 parts Antioxidant Sanol LS2626: Sankyo Chemical Co., Ltd. 1 part Dispersant polycarboxylic acid compound BYK P104: Big Chemie 0.4 part Curing agent Dibutyltin acetate 1 Part solvent 2-propanol 200 parts

Example 2 The α-alumina particles of the coating solution for the cross-linking protective layer of Example 1 were changed to 15 parts of α-alumina particles (Sumicorundum AA-05: manufactured by Sumitomo Chemical Co., Ltd.),
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the antioxidant was not included.

[Example 3] Example 3 except that 15 parts of α-alumina particles (Sumicorundum AA-07: manufactured by Sumitomo Chemical Co., Ltd.) were used as the components of the coating solution for the cross-linking protective layer of Example 1. An electrophotographic photosensitive member was produced in the same manner as in 1.

[Example 4] Example 4 except that the α-alumina particles of the coating solution for the cross-linking protective layer of Example 1 were changed to 15 parts of α-alumina particles (Taimicron TM-DAR: manufactured by Daimei Chemical Industry Co., Ltd.). An electrophotographic photosensitive member was produced in the same manner as in 1.

[Example 5] The α-alumina particles of the coating solution for the cross-linking protective layer of Example 1 were changed to 15 parts of α-alumina particles (Tymicron TM-5D: manufactured by Daimei Chemical Industry Co., Ltd.), and an antioxidant was used. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that it was not contained.

[Example 6] The organic silane compound having a hydrolyzable group in the coating solution for the cross-linking protective layer of Example 1 was changed to 80 parts of methyltrimethoxysilane and 30 parts of γ-glycidoxypropyltrimethoxysilane. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the above was used.

[Example 7] The same as Example 1 except that the charge transporting compound having a functional group of the coating solution component for the cross-linking protective layer of Example 1 was changed to 35 parts of [HT-2] having the following structure. An electrophotographic photoreceptor was produced.

[0090]

[Chemical 4]

[Example 8] The same as Example 1 except that the charge transporting compound having a functional group of the coating solution component for the cross-linking protective layer of Example 1 was changed to 35 parts of [HT-3] having the following structure. An electrophotographic photoreceptor was produced.

[0092]

[Chemical 5]

[Comparative Example 1] An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the coating liquid component for cross-linking protective layer of Example 1 was not added with α-alumina particles.

Comparative Example 2 Example 1 was repeated except that 15 parts of rutile-type titanium oxide powder (CR-EL: manufactured by Ishihara Sangyo Co., Ltd.) was used as the α-alumina particles of the coating solution for the cross-linking protective layer of Example 1. An electrophotographic photoreceptor was prepared in the same manner as in.

[Comparative Example 3] The α-alumina particles of the coating solution for the cross-linking protective layer of Example 1 were replaced by spherical silica particles (KE-P3).
(0: manufactured by Nippon Shokubai Co., Ltd.) An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the amount was changed to 15 parts.

[Comparative Example 4] The α-alumina particles of the coating solution for the cross-linking protective layer of Example 1 were replaced by spherical silica particles (KE-P3).
0: manufactured by Nippon Shokubai Co., Ltd.) An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the dispersant was not included.

[Comparative Example 5] The α-alumina particles of the coating liquid component for the cross-linking protective layer of Example 1 were converted into α-alumina particles (AA-
2: manufactured by Sumitomo Chemical Co., Ltd.) An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the amount was changed to 15 parts.

[Comparative Example 6] The α-alumina particles as the coating liquid component for the cross-linking protective layer of Example 1 were converted to ultrafine alumina particles (Aluminiu).
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the amount was changed to 15 parts.

[Comparative Example 7] The procedure of Example 1 was repeated except that 50 parts of colloidal silica (methanol dispersion, solid content 30% by weight) was used as the α-alumina particles of the coating solution for the cross-linking protective layer, and no dispersant was added. An electrophotographic photosensitive member was produced in the same manner as in Example 1.

[Comparative Example 8] The α-alumina particles of the coating solution for the cross-linking protective layer of Example 1 were converted into α-alumina powder (AL-M).
41: manufactured by Sumitomo Chemical Co., Ltd.) Example 1 except that the amount was changed to 15 parts.
An electrophotographic photoreceptor was prepared in the same manner as in.

[Comparative Example 9] An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the content of the α-alumina particles as a component of the coating solution for the crosslinking protective layer in Example 1 was changed to 100 parts.

Comparative Example 10 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the siloxane cross-linking protective layer of Example 1 was not provided. Data sheet of inorganic filler used in the examples

[0103]

[Table 1-1]

[0104]

[Table 1-2] *: Cumulative 10% from the fine particle side, cumulative 90 as the particle size distribution
When the particle diameters of% are Da and Db, respectively, Db / Da
The value of the

The electrophotographic photoconductors of Examples 1 to 8 and Comparative Examples 1 to 10 produced as described above were mounted in a process unit for an electrophotographic apparatus, and were manufactured by Ricoh's IPSIO Color.
Perform image evaluation and electrical property evaluation using 8000. q
It was. First, the initial image and the exposed portion potential were measured in an environment of temperature 25 ° C. and humidity 55%, and after that, as an acceleration test of the charging load, the sample was left in an ozone gas atmosphere of 5 ppm for 10 hours, and then returned to the same environment as the initial image. Confirmed the change. After that, copying was further performed on 30,000 sheets, and the image change, the exposed portion potential, and the abrasion amount of the photoconductor after the copying was completed were examined. The results are shown in Table 2.

[0106]

[Table 2-1]

[0107]

[Table 2-2]

From the evaluation results of Table 2, 0.1 to 1.0 μm
It can be seen that the photoconductor having the charge-transporting siloxane protective layer containing α-alumina is excellent in abrasion resistance, electrical characteristics and ozone resistance, and a good image can be continuously obtained. On the other hand, the protective layer containing no inorganic filler of Comparative Example 1 has poor wear resistance and a short life of the photoreceptor. Also,
Those using the inorganic fillers of Comparative Examples 2 to 8 other than the present invention have problems in ozone resistance, surface irregularities, rise in exposed area potential, etc. and cannot withstand long-term actual use. Further, the one containing a large amount of the α-alumina particles of the present invention has a great deterioration in electric characteristics and cannot be used.

Therefore, by providing the siloxane protective layer containing 0.1 to 1.0 μm of α-alumina and chemically bonding the charge transporting structure, it has high durability and is good for repeated use. It has been found that it is possible to provide a high-performance and highly reliable electrophotographic photosensitive member capable of continuously obtaining a large image. In addition, it was also found that the image forming method, the image forming apparatus and the process unit for the image forming apparatus using the electrophotographic photosensitive member of the present invention have high performance and high reliability.

[0110]

As is clear from the detailed and specific description above, according to the present invention, the protective layer has a siloxane crosslinked structure in which structural units having a charge transporting property are chemically bonded and has an average particle size of 0.1. By including α-alumina particles having a particle size of up to 1.0 μm, it is possible to provide a highly durable, high-performance and highly reliable electrophotographic photoreceptor having high abrasion resistance and high image quality, and also to provide the present invention. By using an electrophotographic photoreceptor, a high-performance and highly reliable image forming method,
An image forming apparatus and a process unit for the image forming apparatus can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a photoconductor of the present invention.

FIG. 2 is a cross-sectional view showing another example of the photoconductor of the present invention.

FIG. 3 is a cross-sectional view showing another example of the photoconductor of the present invention.

FIG. 4 is a schematic view showing an example of an image forming apparatus of the present invention.

FIG. 5 is a schematic view showing an example of a process unit for an image forming apparatus of the present invention.

[Explanation of symbols]

1 photoconductor 2 Static elimination lamp 3 Charger 4 Eraser 5 Image exposure unit 6 Development unit 7 Charger before transfer 8 Registration roller 9 Transfer paper 10 Transfer charger 11 Separation Charger 12 separate nails 13 Charger before cleaning 14 fur brush 15 Cleaning blade 31 conductive support 33 Photosensitive layer 35 Charge generation layer 37 Charge Transport Layer 39 Protective layer 101 photosensitive drum 102 charging device 103 exposure 104 developing device 105 transfer body 106 transfer device 107 cleaning blade

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08K 5/092 C08K 5/092 C08L 83/04 C08L 83/04 F term (reference) 2H068 AA03 AA04 BA04 BA12 BA60 BB33 BB49 BB57 CA33 FA01 FA27 4J002 BC042 BG012 CF002 CP051 CP081 CP091 CP101 CP151 DE146 EF067 FD010 FD016 FD150 FD312 FD317 GF00 GH00 GS00 4J035 BA11 CA042 CA072 CA132 CA152 CA172 CA182 CA192 CA202 CA222 CA262 EA01 LA03 EB01 EA01 LA01 EB01 LB01 EA01 LA01 EB01

Claims (8)

[Claims] 1. A laminated electrophotographic photosensitive member comprising a conductive support and at least a photosensitive layer and a protective layer sequentially provided on the conductive support, the protective layer having a siloxane crosslinked structure in which structural units having a charge transporting property are chemically bonded, And the average particle size is 0.1 to 1.
An electrophotographic photoreceptor containing 0-μm α-alumina particles. 2. The electrophotographic photosensitive member according to claim 1, wherein the structural unit having a charge transporting property of the protective layer has a triarylamine structure as an element. 3. A substituted or unsubstituted alkyl in which the silicon atom in the siloxane cross-linking structure of the protective layer has a trivalent bond of tetravalent bonds by hydrolysis and the remaining monovalent is not involved in the cross-linking. The electrophotographic photosensitive member according to claim 1, which contains 50% or more of those having a group or a phenyl group with respect to the total silicon. 4. When the particle size distribution of the α-alumina particles is 10% cumulative and 90% cumulative 90% from the fine particle side of the cumulative particle size distribution, Da and Db, respectively, the value of Db / Da is 5. The electrophotographic photosensitive member according to any one of claims 1 to 3, which is α-alumina having the following particle size distribution. 5. The α-alumina particles have a sodium content of 20 ppm or less as impurities and a purity of 99.95% by weight or more.
4. The electrophotographic photosensitive member according to any one of 1 to 4. 6. The electrophotographic photosensitive member according to any one of claims 1 to 5, wherein the protective layer contains a polycarboxylic acid compound. 7. An image forming apparatus using the electrophotographic photosensitive member according to claim 1, further comprising a charging unit, an exposing unit, a developing unit, and a transferring unit. 8. A charging unit, a developing unit, a transfer unit, comprising the electrophotographic photosensitive member according to claim 1.
A process unit for an image forming apparatus, characterized in that at least one means selected from the group consisting of a cleaning means and a charge eliminating means is integrated and detachable.