JP2006235211A - Method for manufacturing electrophotographic photoreceptor, electrophotographic photoreceptor, process cartridge and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor of long life with which saving of resources in manufacturing of the photoreceptor and the curtailment of the amount of waste of the photoreceptor are made possible and the electrophotographic photoreceptor of a high yield, a process cartridge loaded with the photoreceptor and an electrophotographic apparatus. <P>SOLUTION: The method for manufacturing the electrophotographic photoreceptor by forming a photosensitive layer composed of a charge generating layer and a charge transport layer on a conductive substrate and further laminating a curable protective layer thereon is characterized in that the method comprises a step of applying a coating liquid containing a curable charge transport component, a curable binder component, and a silicon-free defoaming agent for forming the protective layer on the photosensitive layer and drying the coating to generate a crosslinking reaction in the protective layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a method for manufacturing an electrophotographic photoreceptor, an electrophotographic photoreceptor, a process cartridge, and an electrophotographic apparatus.
The process cartridge and the electrophotographic apparatus of the present invention are applied to a copying machine, a facsimile, a laser printer, a direct digital plate making machine, and the like.

  More than 10 years have passed since the adoption of the action plan “Agenda 21”, which was established with the hope of passing on the rich global environment to the next generation, and it can be said that public awareness of environmental protection has deepened considerably. For example, it has become a familiar example of consciousness change that the garbage has been sorted and the back paper has been frequently used as printing paper. At present, the environmental performance of industrial products is becoming more and more important to the public. In recent years, electrophotographic photoconductors have been energetically researched and developed to reduce environmental impact. When looking at the life cycle from raw material mining to disposal of the electrophotographic photosensitive member, it is necessary to promote the extension of the life and detoxification of the health of the electrophotographic photosensitive member first.

Conventionally, the usage of electrophotographic photoreceptors has a strong character as a supply product, so there is room for improvement in resource saving and waste reduction. In order to cope with this, it is important to improve the durability of the photosensitive member by suppressing the wear and wound of the photosensitive member from the viewpoint of designing and using the photosensitive member.
At present, an amorphous silicon photoconductor can be cited as a typical high durability photoconductor.

  However, since the manufacturing method is a dry process, the manufacturing cost is high, and the object of use is limited to high-end machines with some exceptions. The high durability of the amorphous silicon photoconductor is considered to have not contributed to reducing the environmental load more than feeling because the ratio of use to the whole is small. In order to reduce the environmental load, it is necessary to reduce the cost in addition to increasing the durability of the photoreceptor because it is necessary to increase the usage ratio. For this purpose, it is advantageous to select a low-cost organic photoreceptor that is highly durable.

  Changes in the binder resin for high durability of organic photoreceptors (for example, Non-Patent Document 1 Hiroyuki Tamura, Saeko Takahashi, Hironobu Morishita, Hideharu Sakamoto, Haruo Shikuma, Japan Hardcopy '97 Fall Meeting, 25-28, 1997), High molecular weight charge transport materials (for example, JP-A-7-325409), coating of a curable protective layer containing a high-hardness filler (for example, JP-A-2002-258499), cross-linking resin film Film formation on the surface of the photoconductor (for example, JP-A-2000-66424) and film formation of a sol-gel cured film on the surface of the photoconductor (for example, JP-A-2000-171990) have been studied. ing. Each of these measures has advantages and disadvantages. In particular, the last two types of measures that have a cross-linked structure are that the coating is formed by multiple chemical bonds, so even if the coating is stressed and part of the chemical bond breaks, it immediately progresses to wear. There is no. Among the above, it is considered to be a particularly rational measure. For convenience, these measures will be classified as “curing type protective layers”.

The resin material used for forming the curable protective layer is advantageously a material having a high crosslink density and intermolecular cohesive force. Photo-curing acrylic resins, thermosetting sol-gel cured films, urethane resins, and melamine resins are generally recognized as hard coating materials (Non-Patent Document 2, Kenji Kushi, Coating Technology, 70-74, 1996). When these materials are used for the curable protective layer, generally good wear resistance can be obtained.
In these materials, spine-like protrusions are formed on the surface of the photoreceptor due to so-called “boil” generated in the film forming process, and local depressions such as pinholes may be generated due to sink marks. Many. This leads to a problem that the end of the cleaning blade is missing.

  In the prior art for preventing the cleaning blade from being chipped, there is a contrivance (for example, Japanese Patent Application Laid-Open No. 2004-109920) in which abrasive fine particles are added to the cleaning blade and the driving torque of the photosensitive member is limited. A device for heating the blade (for example, JP-A-7-28368) or a device for sucking and removing foreign matters such as a developer carrier (for example, JP-A-6-35372) has been proposed. . These are the contents to be improved by the contrivance of the electrophotographic apparatus, and preferably the defects should be solved by suppressing coating film defects. However, it still cannot be solved. Sorting out photoconductors with no coating defects was an extremely poor yield and was a major factor hindering practical use.

JP 7-325409 A JP 2002-258499 A JP 2000-66424 A JP 2000-171990 A JP 2004-109920 A JP-A-7-28368 JP-A-6-35372 Hiroyuki Tamura, Saeko Takahashi, Hironobu Morishita, Hideharu Sakamoto, Haruo Shikuma, Japan Hardcopy '97 Fall Meeting, 25-28, 1997 Kushi Kenji, Painting Technology, 70-74, 1996

  A long-life electrophotographic photosensitive member capable of saving resources and reducing the amount of waste of the photosensitive member, a method of manufacturing an electrophotographic photosensitive member with excellent yield, and a process cartridge and an electrophotographic apparatus equipped with the photosensitive member The purpose is to provide.

That is, the said subject is solved by (1)-(9) of this invention.
(1) In the method for producing an electrophotographic photosensitive member, in which a curable protective layer is further laminated on a photosensitive layer comprising a charge generation layer and a charge transport layer on a conductive support, a curable charge transport component is formed on the photosensitive layer. A method for producing an electrophotographic photosensitive member comprising a step of applying a coating solution for forming a protective layer containing a curable binder component and a silicon-free antifoaming agent, drying, and causing a crosslinking reaction in the protective layer ";
(2) "The silicon-free antifoaming agent is at least polyoxyethylene alkyl ethers, polyoxyethylene alkylphenols, polyhydric alcohol fatty acid esters, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan, The method for producing an electrophotographic photosensitive member according to the above item (1), which is one or more of fatty acid esters, polyoxyethylene alkylamines, and polyoxyethylene amides;
(3) “The content of the silicon-free antifoaming agent is 0.1 wt% or more and less than 6 wt% of the total solid content in the coating liquid” Method for producing electrophotographic photosensitive member according to item 2);
(4) “Any of the above-mentioned items (1) to (4), wherein the curable charge transporting component contains at least one of the compounds represented by the following general formulas (1) to (3): An electrophotographic photoreceptor according to any one of the above.

式中、Ｒ_２は水素原子、アルキル基、フッ素原子、シアノ基、フェニル基又はハロゲン原子で置換されたアルキル基、Ｃ_１〜Ｃ_４のアルキル基で置換されたフェニル基で置換されたアルキル基、アリール基、フッ素原子、シアノ基、フェニル基又はハロゲン原子で置換されたアリール基、Ｃ_１〜Ｃ_４のアルキル基で置換されたフェニル基で置換されたアリール基を表わし、Ｒ_３は水素原子、アルキル基、フッ素原子、シアノ基、フェニル基又はハロゲン原子で置換されたアルキル基、Ｃ_１〜Ｃ_４のアルキル基で置換されたフェニル基で置換されたアルキル基、アリール基、フッ素原子、シアノ基、フェニル基又はハロゲン原子で置換されたアリール基、Ｃ_１〜Ｃ_４のアルキル基で置換されたフェニル基で置換されたアリール基、ハロゲン原子を表わし、Ｒ_３は水素原子を表わし、Ａｒ_１、Ａｒ_２はアリール基、ハロゲン原子又はアルキル基で置換されたアリール基を表わす。但し、Ｒ_３が水素原子、且つＡｒ_１及びＡｒ_２がｐ−トリル基である場合を除く。
Ｘは下記（ａ）〜（ｄ）のいずれかを表わす。
（ａ）アルキレン基
（ｂ）フッ素原子、シアノ基、フェニル基、又はハロゲン原子若しくはＣ_１〜Ｃ_５のアルキル基で置換されたフェニル基によって置換されたアルキレン基
（ｃ）アリーレン基
（ｄ）下記一般式（４）で表わされる基

In the formula, R ₂ is a hydrogen atom, an alkyl group, a fluorine atom, a cyano group, an alkyl group substituted with a phenyl group or a halogen atom, or an alkyl group substituted with a phenyl group substituted with a C _{1 to} C ₄ alkyl group. , an aryl group, a fluorine atom, a cyano group, a phenyl group, or an aryl group substituted by a halogen atom, an aryl group substituted with a phenyl group substituted with an alkyl group of C ₁ ~C _4, R ₃ is a hydrogen atom , alkyl group, a fluorine atom, a cyano group, a phenyl group or a halogen atom-substituted alkyl group, C ₁ -C ₄ alkyl group substituted by an alkyl group substituted with a phenyl group, an aryl group, a fluorine atom, a cyano group, a phenyl group, or an aryl group substituted by a halogen atom, C ₁ -C ₄ aryl group substituted with a phenyl group substituted with an alkyl group, c Represents a Gen atom, R ₃ represents a hydrogen atom, Ar _1, Ar ₂ represents an aryl group, an aryl group substituted with a halogen atom or an alkyl group. However, the case where R ₃ is a hydrogen atom and Ar ₁ and Ar ₂ are p-tolyl groups is excluded.
X represents any of the following (a) to (d).
(A) an alkylene group (b) a fluorine atom, a cyano group, a phenyl group, or a halogen atom or a C ₁ -C ₅ alkylene group (c) an arylene group substituted by a phenyl group substituted with an alkyl group (d) below Group represented by general formula (4)

｛式中、Ｙは−Ｏ−、−Ｓ−、−ＳＯ−、−ＳＯ_２−、−ＣＯ−及び以下の２価基を表わす。

{In the formula, Y is -O -, - S -, - SO -, - SO 2 -, - CO- and represent divalent groups below.

（ここで、Ｒ_５、Ｒ_６は水素原子、アルキル基、前記（ｃ）で定義された置換基を有するアルキル基、アルコキシ基、ハロゲン原子、アリール基、前記（ｅ）で定義された置換基を有するアリール基、アミノ基、ニトロ基、シアノ基を表わし、ｐ、ｑ、ｒ、ｓは１〜１２の整数を表わす）｝

(Wherein R ₅ and R ₆ are a hydrogen atom, an alkyl group, an alkyl group having a substituent defined in (c), an alkoxy group, a halogen atom, an aryl group, and a substituent defined in (e) above) Represents an aryl group having an amino group, an amino group, a nitro group, or a cyano group, and p, q, r, and s represent an integer of 1 to 12)}

Ｒ_７、Ｒ_８は置換もしくは無置換のアリール基を表わす。Ｒ_７、Ｒ_８は同一であっても異なってもよい。
また、Ａｒ_３、Ａｒ_４およびＡｒ_５で示されるアリーレン基としてはＲ_５およびＲ_６と同様のアリール基の２価基が挙げられ、同一であっても異なってもよい。
Ｘは一般式（２）で挙げたものと同じである。

R ₇ and R ₈ represent a substituted or unsubstituted aryl group. R ₇ and R ₈ may be the same or different.
The arylene group represented by Ar ₃ , Ar ₄ and Ar ₅ includes the same divalent group as the aryl group as R ₅ and R ₆ , which may be the same or different.
X is the same as that mentioned in the general formula (2).

Ｒ_９、Ｒ_１０は置換もしくは無置換のアリール基を表わす。Ｒ_９、Ｒ_１０は同一であっても異なってもよい。
また、Ａｒ_６、およびＡｒ_７で示されるアリーレン基としてはＲ_９およびＲ_１０と同様のアリール基の２価基が挙げられ、同一であっても異なってもよい。
Ｘは一般式（２）で挙げたものと同じである」；
（５）「前記硬化型バインダー成分がメラミン樹脂、ウレタン樹脂またはアクリル樹脂であることを特徴とする前記第（１）項乃至第（４）項のいずれかに記載の電子写真感光体の製造方法」；
（６）「前記硬化型バインダー成分がゾル−ゲル法によるガラス質形成成分であることを特徴とする前記第（１）項乃至第（４）項のいずれかに記載の電子写真感光体の製造方法」；
（７）「前記第（１）項乃至第（６）項のいずれかに記載の製造方法によって得られることを特徴とする電子写真感光体」；
（８）「少なくとも前記第（７）項に記載の電子写真感光体を搭載することを特徴とするプロセスカートリッジ」；
（９）「前記第（７）項に記載の電子写真感光体または前記第（８）項に記載のプロセスカートリッジを搭載することを特徴とする電子写真装置」。

R ₉ and R ₁₀ represent a substituted or unsubstituted aryl group. R ₉ and R ₁₀ may be the same or different.
In addition, the arylene group represented by Ar ₆ and Ar ₇ includes the same divalent group of an aryl group as R ₉ and R ₁₀ , which may be the same or different.
X is the same as mentioned in the general formula (2) ";
(5) “The method for producing an electrophotographic photosensitive member according to any one of (1) to (4) above, wherein the curable binder component is a melamine resin, a urethane resin, or an acrylic resin. ";
(6) Production of an electrophotographic photosensitive member according to any one of (1) to (4) above, wherein the curable binder component is a vitreous forming component by a sol-gel method. Method";
(7) “Electrophotographic photosensitive member obtained by the production method according to any one of (1) to (6)”;
(8) “Process cartridge comprising at least the electrophotographic photosensitive member according to item (7)”;
(9) “Electrophotographic apparatus including the electrophotographic photosensitive member according to (7) or the process cartridge according to (8)”.

  The electrophotographic photoreceptor of the present invention has a long life that enables resource saving and waste reduction. According to the production method of the present invention, it is possible to produce a photoreceptor having a very small yield and excellent yield on the photoreceptor surface.

In order to obtain the smoothness of the coating film, a means of adding several percent leveling agent to the paint is effective. Most leveling agents used in the manufacture of electrophotographic photoreceptors can be referred to as silicones.
When a leveling agent is added to the coating of the curable protective layer, the smoothness of the coating film surface tends to be improved. When the inventor forms a film by this means, the curable protective layer becomes brittle as it approaches the photosensitive layer side, and when used in a high humidity environment, the inventors faced a problem that the resolution of the printed image deteriorates. .

Silicon-based leveling agents exhibit excellent leveling action, but due to their dimethylsiloxane structure, they have releasability and are easily transferred from the paint film to the vicinity of the film surface (for example, page 153 of the Silicon Handbook). Although the mold protective layer is said to have a certain degree of heat resistance during film formation, the crosslinking reaction proceeds at a relatively high temperature of about 140 ° C., or the coating itself may generate heat at a high temperature due to the crosslinking reaction. Many. At this time, it is considered that a part of the leveling agent undergoes oxidative decomposition or the like, thereby forming a release layer in the film. In addition, when the coated protective layer paint has poor adhesion to the ground, it seems that the mechanical strength at the interface between the photosensitive layer and the curable protective layer is impaired. As a result, it was conceived that the curable protective layer becomes brittle as it approaches the photosensitive layer side.
On the other hand, it was considered that the image blur was caused by the decomposition of the leveling agent silicone, resulting in the formation of many silanol groups in the curable protective layer.

The inventor considered that the combined use of a silicone leveling agent was not preferable for the curable protective layer, and as a result of intensive studies, the specific use mode of the silicone-free antifoaming agent solved these problems while satisfying the leveling action. The inventors have found what can be done and have completed the present invention.
Silicone-free antifoaming agents include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenols, polyhydric alcohol fatty acid esters, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene / sorbitan / fatty acid esters, Polyoxyethylene alkylamines and polyoxyethylene amides are suitable.

The electrophotographic apparatus used in the present invention will be described below with reference to the drawings.
Desktop or floor using indirect electrophotography (zero graph method) such as facsimile, laser printer, electrophotographic copying machine, direct plate-making machine and multi-function machines that are widely used as devices for image formation In general, an image forming apparatus of a type includes an electrophotographic photosensitive member (or an image carrier), a charging unit, an image exposing unit, a developing unit, a transferring unit, a separating unit, a cleaning unit, a discharging unit, a fixing unit, a copy sheet (a transfer target). Body), a paper discharge tray, and the like.

FIG. 1 shows a schematic diagram of an image forming apparatus using an electrophotographic system.
Electrophotographic photoreceptors (1) (hereinafter simply referred to as photoreceptors) used for image formation include selenium (a-Se, a-Se ₂ Se ₃ , a-SeTe, etc.), silicon (a-Si: H, a-Si: Ge: H, etc.), CdSe series, CdS series, ZnO series and other photosensitive materials are known. An organic photoreceptor on which a curable protective layer obtained by the production method of the present invention, which is friendly to the global environment, is mounted.
Charging is performed by charging means (2) disposed opposite to the photoreceptor (1).
Corona charging devices, contact charging devices, proximity charging devices (or non-contact charging devices) are known as charging means (2).

In the corona charging device, a 40 to 60 (μm) discharge wire (for example, a tungsten wire) is placed in a U-shaped shield case, a DC voltage of −4000 to −6000 V is applied, It is a charging device that is separated by about 10 mm and is charged by silent discharge.
When negative charging is performed, since the discharge is non-uniform, a grid is usually installed to equalize the charging potential.

The contact charging device and the proximity charging device are a brush-like charging member composed of carbon fiber or a low resistance material such as carbon dispersed in chemical fiber, and a resistance-controlled fiber, or epichlorohydrin rubber alone, or further carbon. Addition to control resistance, roller-shaped charging member configured by adding fluororesin or silica as required, roller shape with resistance control by dispersing carbon, metal powder, ionic conductive material in resin There are charging members and the like. The charging members are mounted on the unit, and are placed in contact with the photosensitive member (1) (contact charging device) or separated from the photosensitive member by about 30 to 80 μm (proximity charging device). A DC voltage of −400 to −1000 (V) or a voltage in which an AC voltage of 800 to 2500 V / 800 to 4500 Hz is superimposed on the DC voltage is applied to the charging member.
The charging level of the photoreceptor is set to about -400 to -800V.

  Although the corona charging device is excellent in charging followability, there is an environmental problem because ozone is generated in a large amount (around 10 ppm). On the other hand, the contact charging method or proximity charging method (or non-contact charging) has a problem that the charging member is contaminated and charging non-uniformity easily occurs because it is in contact with or close to the photoconductor. In recent years, it has been widely used as a charging means because it has the advantages of being small and energy saving, producing less ozone (about 0.05 to 0.3 ppm) and being excellent in environmental properties.

After the photoreceptor (1) is uniformly charged, the original image and the signal from the personal computer are output by an image exposure means (3) comprising a CCD, LD element or LED element, polygon mirror, filter, cylindrical lens, and the like. Irradiation with a dot pattern forms a digital pattern electrostatic latent image (light-dark potential difference) on the photoreceptor (1).
The electrostatic latent image is developed by developing means (4) using a magnet brush developing method.
The developing means (4) contains a magnetic powder called a carrier having an average particle diameter of about 40 to 80 μm and a developer composed of toner having a particle diameter of about 4 to 10 μm, and the toner concentration is 3 to 8% by weight. Set to degree. A developing bias is applied to the developing means (4) for development.

The toner used in the developer includes a pulverized toner manufactured by a mechanical manufacturing method having irregular shapes and irregularities, and a polymerized toner manufactured by a chemical manufacturing method (such as a suspension polymerization method or an emulsion polymerization method). However, in recent years, with the demand for high image quality, there is a tendency to increase the use of polymerized toner that is less expensive than pulverized toner, has a relatively uniform shape, and has a substantially uniform charge.
The toner image obtained by the development is transferred from the paper feed tray (10) by the transfer means (5) integrated with the static elimination charger (6) and applied with a voltage opposite to the toner band electrode. The image is transferred onto the body (copy paper) (11), conveyed to the fixing means (9), fixed and made into a hard copy (13), and discharged to the paper discharge tray (12).
After the transfer, the residual toner on the photoreceptor is cleaned by a cleaning means (7) comprising a cleaning blade (71) using a rubber-like elastic body as a blade, and then the entire surface of the photoreceptor is irradiated by a charge eliminating means (8). Then, the internal latent image is neutralized and electrically initialized to complete a series of copying cycles.
The image forming apparatus is not limited to the configuration shown in FIG. 1, and the photoconductor (1) in the form of a belt, the photoconductor is color-printed in a tandem layout, or the electronic is printed via an intermediate transfer body. A photographic device is also used.

  Further, the image forming means as described above may be fixedly incorporated in a copying machine, a facsimile, or a printer, but may be incorporated in these apparatuses in the form of a process cartridge. The process cartridge in the present invention is a module including a photoconductor and further including a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit.

FIG. 2 is a sectional view schematically showing an example of the electrophotographic photosensitive member of the present invention. On the conductive support (21), a charge generation layer (22), a charge transport layer (23), and a curable protective layer ( 24) is provided.
FIG. 3 is a cross-sectional view schematically showing an example of an electrophotographic photosensitive member having another layer structure of the present invention. An undercoat layer (25) is provided between the conductive support (21) and the charge generation layer (22). ), And a charge transport layer (23) and a curable protective layer (24) are provided on the charge generation layer (22).
Examples of the conductive support (21) include those having a volume resistance of 10 ¹⁰ Ω · cm or less, such as metals such as aluminum, nickel, chromium, nichrome, copper, silver, gold, platinum, iron, tin oxide, A film or cylindrical plastic or paper coated with an oxide such as indium oxide by vapor deposition or sputtering, or a plate made of aluminum, aluminum alloy, nickel, stainless steel, or the like, and a drawing ironing method, impact It is possible to use a tube that has been surface-treated by cutting, superfinishing, polishing, or the like after being made into a bare pipe by a method such as the Ironing method, the Extruded Ironing method, the Extruded Drawing method, or the cutting method.

In the electrophotographic photoreceptor used in the present invention, an undercoat layer (25) can be provided between the conductive support and the photosensitive layer. The undercoat layer is provided for the purpose of improving adhesiveness, preventing moire, improving coatability of the upper layer, and preventing charge injection from the conductive support.
The undercoat layer usually contains a resin as a main component. Usually, since the photosensitive layer is applied on the undercoat layer, the resin used for the undercoat layer is preferably a thermosetting resin that is hardly soluble in an organic solvent. In particular, polyurethane, melamine resin, and alkyd-melamine resin are particularly preferable materials because many of them sufficiently satisfy the above purpose. The resin can be used as a coating material which is appropriately diluted with a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, butanone and the like.

In addition, fine particles such as metal or metal oxide may be added to the undercoat layer in order to adjust conductivity and prevent moire. In particular, titanium oxide is preferably used.
The fine particles are dispersed in a ball mill, attritor, sand mill or the like using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, or butanone to obtain a coating material in which the dispersion and the resin component are mixed.

The undercoat layer is formed by depositing the above-mentioned paint on a support by a dip coating method, spray coating method, bead coating method or the like and, if necessary, heat curing.
In many cases, the thickness of the undercoat layer is suitably about 2 to 5 μm. When the accumulation of the residual potential of the photoconductor becomes large, it is preferable to set it below 3 μm.

The photosensitive layer in the present invention is preferably a laminated photosensitive layer in which a charge generation layer and a charge transport layer are sequentially laminated.
Of the layers in the multilayer photoreceptor, the charge generation layer (22) will be described. The charge generation layer refers to a part of the laminated photosensitive layer and has a function of generating charges by exposure. This layer is mainly composed of a charge generating substance among the contained compounds. For the charge generation layer, a binder resin may be used as necessary. As the charge generation material, inorganic materials and organic materials can be used.

  Examples of the inorganic material include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compound, and amorphous silicon. In amorphous silicon, a dangling bond that is terminated with a hydrogen atom or a halogen atom, or a material that is doped with a boron atom or a phosphorus atom is preferably used.

  On the other hand, as the organic material, known materials can be used, for example, metal phthalocyanines such as titanyl phthalocyanine and chlorogallium phthalocyanine, metal-free phthalocyanines, azulenium salt pigments, squaric acid methine pigments, and symmetrical types having a carbazole skeleton. Alternatively, an asymmetric azo pigment, a symmetric or asymmetric azo pigment having a triphenylamine skeleton, a symmetric or asymmetric azo pigment having a fluorenone skeleton, a perylene pigment, and the like can be given. Among these, metal phthalocyanines, symmetric or asymmetric azo pigments having a fluorenone skeleton, symmetric or asymmetric azo pigments having a triphenylamine skeleton, and perylene pigments have a high quantum efficiency of charge generation, and thus are suitable for the present invention. It is suitable as a material to be used. These charge generation materials may be used alone or as a mixture of two or more.

  The binder resin used as necessary for the charge generation layer includes polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, polyarylate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-. Examples thereof include vinyl carbazole and polyacrylamide. Moreover, the polymeric charge transport material mentioned later can also be used. Of these, polyvinyl butyral is often used and is useful. These binder resins may be used alone or as a mixture of two or more.

Methods for forming the charge generation layer are roughly classified into a vacuum thin film preparation method and a casting method from a solution dispersion system.
Examples of the former method include a vacuum deposition method, a glow discharge decomposition method, an ion plating method, a sputtering method, a reactive sputtering method, and a CVD (chemical vapor deposition) method. Can be formed satisfactorily.

In addition, in order to provide the charge generation layer by the casting method, the above-described inorganic or organic charge generation material may be combined with a binder resin, if necessary, using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, butanone, ball mill, attritor. The dispersion may be dispersed by a sand mill or the like, and the dispersion may be diluted appropriately. Among these solvents, methyl ethyl ketone, tetrahydrofuran, and cyclohexanone are preferable because they have a lower environmental impact than chlorobenzene, dichloromethane, toluene, and xylene. Application can be performed by dip coating, spray coating, bead coating, or the like.
The thickness of the charge generation layer provided as described above is usually about 0.01 to 5 μm.

When it is necessary to reduce the residual potential and increase the sensitivity, these characteristics are often improved by increasing the thickness of the charge generation layer. On the other hand, the chargeability often deteriorates, such as the charge charge retention and space charge formation. From these balances, the thickness of the charge generation layer is more preferably in the range of 0.05 to 2 μm.
Further, if necessary, low-molecular compounds such as antioxidants, plasticizers, lubricants and ultraviolet absorbers and leveling agents described later can be added to the charge generation layer. These compounds can be used alone or as a mixture of two or more. When a low molecular weight compound and a leveling agent are used in combination, sensitivity deterioration often occurs. For this reason, the amount of these used is generally 0.1 to 20 phr, preferably 0.1 to 10 phr, and the amount of the leveling agent used is suitably about 0.001 to 0.1 phr.

Next, the charge transport layer (23) will be described.
The charge transport layer refers to a part of the laminated photosensitive layer that functions to inject and transport charges generated in the charge generation layer and to neutralize the surface charge of the photoreceptor provided by charging. The main component of the charge transport layer can be referred to as a charge transport component and a binder component that binds the charge transport component.

  Examples of materials that can be used for the charge transport material include low molecular weight electron transport materials, hole transport materials, and polymer charge transport materials.

Examples of the electron transporting material include electron accepting materials such as asymmetric diphenoquinone derivatives, fluorene derivatives, and naphthalimide derivatives.
These electron transport materials may be used alone or as a mixture of two or more.
As the hole transport material, an electron donating material is preferably used.

Examples thereof include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, butadiene derivatives, 9- (p-diethylaminostyrylanthracene), 1,1-bis- (4-dibenzylaminophenyl) propane, Examples include styryl anthracene, styryl pyrazoline, phenylhydrazones, α-phenyl stilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, and thiophene derivatives.
These hole transport materials may be used alone or as a mixture of two or more.

In addition, the following polymer charge transport materials can be used. For example, a polymer having a carbazole ring such as poly-N-vinylcarbazole, a polymer having a hydrazone structure exemplified in JP-A-57-78402, etc., exemplified in JP-A-63-285552, etc. The polysilylene polymer to be used, and aromatic polycarbonates exemplified by general formula (1) to general formula (6) of JP-A No. 2001-330973. These polymer charge transport materials can be used alone or as a mixture of two or more. In particular, the exemplified compounds disclosed in JP-A-2001-330973 are useful because of their good electrostatic characteristics.
The polymer charge transport material is a suitable material for preventing the surface layer from being poorly cured when the curable protective layer is laminated, as compared with the low molecular weight charge transport material. In addition, since the charge transporting substance has a high molecular weight, it has excellent heat resistance, and is advantageous in that it is less susceptible to deterioration due to curing heat when a curable protective layer is formed.

  Examples of the polymer compound that can be used as the binder component of the charge transport layer include polystyrene, polyester, polyvinyl, polyarylate, polycarbonate, acrylic resin, silicone resin, fluorine resin, epoxy resin, melamine resin, urethane resin, and phenol resin. And thermoplastic or thermosetting resins such as alkyd resins. Of these, polystyrene, polyester, polyarylate, and polycarbonate are useful because many of them have good charge transfer characteristics when used as a binder component of a charge transport component. Further, since the charge transport layer has a curable protective layer or a protective layer laminated thereon, the charge transport layer is not required to have mechanical strength as compared with the conventional charge transport layer. For this reason, a material such as polystyrene, which is highly transparent but has a low mechanical strength and is difficult to apply in the prior art, can be effectively used as the binder component of the charge transport layer.

  These polymer compounds can be used singly or as a mixture of two or more kinds, or as a copolymer composed of two or more of these raw material monomers, and further copolymerized with a charge transport material.

When an electrically inactive polymer compound is used for modifying the charge transport layer, a cardo polymer type polyester having a bulky skeleton such as fluorene, a polyester such as polyethylene terephthalate or polyethylene naphthalate, or a C type polycarbonate is used. Polycarbonate in which the 3,3 ′ portion of the phenol component is alkyl-substituted with respect to a bisphenol-type polycarbonate, polycarbonate in which the geminal methyl group of bisphenol A is substituted with a long-chain alkyl group having 2 or more carbon atoms, biphenyl or biphenyl Polycarbonate having an ether skeleton, polycarbonate having a long chain alkyl skeleton such as polycaprolactone and polycaprolactone (for example, described in JP-A-7-292095), acrylic resin, polystyrene, hydrogenated Tadiene is effective.
Here, the electrically inactive polymer compound refers to a polymer compound that does not include a chemical structure exhibiting photoconductivity such as a triarylamine structure.

When these resins are used as an additive in combination with a binder resin, the amount added is preferably 50% by weight or less based on the total solid content of the charge transport layer, due to restrictions on light attenuation sensitivity.
When a low molecular charge transport material is used, the amount used is 40 to 200 phr, preferably about 70 to 100 phr. When a polymer charge transport material is used, a material in which the resin component is copolymerized in an amount of about 0 to 200 parts by weight, preferably about 80 to 150 parts by weight with respect to 100 parts by weight of the charge transport component is preferably used.

When two or more kinds of charge transport materials are contained in the charge transport layer, it is preferable that the difference in ionization potential is small. Specifically, by setting the difference in ionization potential to 0.10 eV or less, Can be prevented from becoming a charge trap of the other charge transport material.
Regarding the relationship between the ionization potentials, the difference between the charge transporting material contained in the charge transporting layer and the curable charge transporting material described later is preferably 0.10 eV.

In addition, the ionization potential value of the charge transport material in the present invention is a numerical value obtained by measuring by a general method using the atmospheric atmospheric ultraviolet photoelectron analyzer AC-1 manufactured by Riken Keiki Co., Ltd.
In order to satisfy high sensitivity, the charge transport component is preferably added in an amount of 70 phr or more. In addition, α-phenylstilbene compounds, benzidine compounds, butadiene compound monomers, dimers, and polymer charge transport materials having these structures in the main chain or side chain are materials having high charge mobility. Many are useful.

  Examples of the dispersion solvent that can be used in preparing the charge transport layer coating solution include ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, and cyclohexanone, ethers such as dioxane, tetrahydrofuran, and ethyl cellosolve, toluene, xylene, and the like. Examples include aromatics, halogens such as chlorobenzene and dichloromethane, and esters such as ethyl acetate and butyl acetate. Of these, methyl ethyl ketone, tetrahydrofuran, and cyclohexanone are preferable because they have a lower environmental impact than chlorobenzene, dichloromethane, toluene, and xylene. These solvents can be used alone or in combination.

  The charge transport layer can be formed by dissolving or dispersing a mixture or copolymer containing a charge transport component and a binder component as main components in an appropriate solvent, and applying and drying the mixture. As the coating method, a dipping method, a spray coating method, a ring coating method, a roll coater method, a gravure coating method, a nozzle coating method, a screen printing method, or the like is employed.

Since a curable protective layer is laminated on the upper layer of the charge transport layer, the thickness of the charge transport layer in this configuration need not be designed to increase the thickness of the charge transport layer in consideration of film scraping in actual use. Thus, it is possible to reduce the thickness.
The film thickness of the charge transport layer is practically about 15 to 40 μm, preferably about 15 to 30 μm for the purpose of ensuring the necessary sensitivity and charging ability.

  If necessary, low-molecular compounds such as antioxidants, plasticizers, lubricants and ultraviolet absorbers and leveling agents described later can be added to the charge transport layer. These compounds can be used alone or as a mixture of two or more. When a low molecular weight compound and a leveling agent are used in combination, sensitivity deterioration often occurs. For this reason, the amount of these used is generally 0.1 to 20 phr, preferably 0.1 to 10 phr, and the amount of the leveling agent used is suitably about 0.001 to 0.1 phr.

Next, the curable protective layer (24) will be described.
For the curable protective layer of the present invention, it is necessary to select a material that forms a three-dimensional network structure through a crosslinking reaction.
As such a material, a sol-gel cured film, a melamine resin, a urethane resin, and an acrylic resin are particularly excellent.
The organometallic compound used as a raw material for the sol-gel cured film is not particularly limited as long as it can be hydrolyzed. A preferred organometallic compound is a metal alkoxide, which is represented by the general formula MR _12m (OR ₁₁ ) _nm . In the formula, M represents a metal having an oxidation number n, R ₁₁ and R ₂ represent an alkyl group, and m represents an integer of 0 to (n−1). R ₁₁ and R ₁₂ may be the same or different. Among them, R ₁₁ and R ₁₂ are preferably alkyl groups having 4 or less carbon atoms, that is, lower alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group and isobutyl group. Such materials are described in, for example, Japanese Patent No. 2924961, although the fields are different.

  Examples of the metal alkoxide include lithium ethoxide, niobium ethoxide, magnesium isopropoxide, aluminum isopropoxide, zinc propoxide, tetraethoxysilane, titanium isopropoxide, barium ethoxide, barium isopropoxide, triethoxyborane. , Zirconium propoxide, lanthanum propoxide, yttrium propoxide, lead isopropoxide and the like. All of these metal alkoxides are commercially available and can be easily obtained. The metal alkoxide is also commercially available as a low condensate obtained by partial hydrolysis, and can be used as a raw material.

  The organometallic compound capable of being hydrolyzed may be used in the reaction as it is, but it is desirable to dilute with a solvent to facilitate the control of the reaction. The dilution solvent may be any solvent that can dissolve the organometallic compound and can be uniformly mixed with water. In general, aliphatic lower alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, ethylene glycol, propylene glycol and mixtures thereof are preferably used. Also, a mixed solvent such as butanol and cellosolve and butyl cellosolve, or xylol and cellosolve acetate, methyl isobutyl ketone and cyclohexane can be used.

When the metal is Ca, Mg, Al or the like in the organometallic compound, it reacts with water in the reaction solution to form a hydroxide, or when carbonate ion CO ₃ ²⁻ is present, carbonate is formed. Since it forms and precipitates, it is desirable to add an alcohol solution of triethanolamine as a masking agent. It is desirable that the concentration of the organometallic compound when mixed and dissolved in a solvent is usually 70% (by weight) or less, particularly 5 to 70% by weight.

The organic solvent used in the reaction solution is not particularly limited as long as it can form a uniform solution with water, acid and alkali, and aliphatic lower alcohols usually used for diluting the organometallic compound are suitable. Among the lower alcohols, propanol, isopropanol, butanol, and isobutanol having more carbon atoms than methanol and ethanol are preferable. This is because the growth of the produced metal oxide glass film and spherical fine particles is stable. The ratio of water and the organic solvent constituting the reaction solution may be in the range of 0.2 to 50 mol / liter as the concentration of water.
In the reaction solution, an organometallic compound is hydrolyzed using a halogen ion as a catalyst in the presence of boron ions. Trialkoxyborane is used as the compound that gives boron ions. Of these, triethoxyborane is preferred. The B ³⁺ ion concentration in the reaction solution is preferably in the range of 1.0 to 10.0 mol / liter. As the halogen ion, F ^- and Cl ^- or a mixture thereof is used.

The compound used may be any compound that generates F ⁻ ions and Cl ⁻ ions in the above reaction solution. For example, ammonium fluoride, sodium fluoride, etc. are used as the F ⁻ ion source, and ammonium chloride is used as the Cl ⁻ ion source. Is preferred.
The concentration of the halogen ions in the reaction solution varies depending on the film thickness of the metal oxide glass to be produced, the diameter of the spherical fine particles, and other conditions, and therefore it is difficult to limit the range. In general, the range of 0.001 to 2 mol / kg, particularly 0.002 to 0.3 mol / kg is preferable with respect to the total weight of the reaction solution containing the catalyst. When the concentration of the halogen ion is lower than 0.001 mol / kg, the hydrolysis of the organometallic compound does not proceed sufficiently, the growth of spherical particles of the metal oxide glass is suppressed, and the film formation becomes difficult. . In addition, when the concentration of halogen ions exceeds 2 mol / kg, the generated metal oxide glass tends to be nonuniform, which is not preferable.

With respect to the boron used during the reaction, if to be contained as a B ₂ O ₃ component in the composition of the metal oxide obtained, by leaving product was added calculated amount of organic boron compound in accordance with the content of If it is desired to remove boron, boron can be removed by evaporation as boron methyl ester by heating after film formation or fine particle formation, in the presence of methanol as a solvent, or by immersion in methanol and heating. .
The hydrolysis reaction of the organometallic compound is usually performed by mixing a base agent solution obtained by mixing and dissolving a predetermined amount of an organometallic compound in a mixed solvent of a predetermined amount of water and an organic solvent, and a predetermined amount of a reaction solution containing a predetermined amount of halogen ions. Are mixed at a predetermined ratio and sufficiently stirred to obtain a uniform reaction solution, and then the pH of the reaction solution is adjusted to a desired value with an acid or an alkali and aged for several hours. A predetermined amount of the boron compound is previously mixed and dissolved in the main agent solution or reaction solution. When alkoxyborane is used, it is advantageous to dissolve it in the main agent solution together with other organometallic compounds.

The pH of the reaction solution must be selected according to the purpose. That is, when aiming at a metal oxide glass film, for example, an acid such as hydrochloric acid is used to adjust the pH to a range of 4.5 to 5 for aging. In this case, for example, it is convenient to use methyl red + bromocresol green as an indicator. For the formation of the film, the reaction solution after aging is applied as it is, or if necessary, an appropriate thickener is added to the surface of the substrate, heated to a temperature of 200 ° C. or lower, dried and vitrified. In heating, the temperature is gradually raised with particular attention being paid to the temperature range of 50 to 70 ° C., followed by a preliminary drying (solvent volatilization) step, and then the temperature is further raised. This drying is particularly important for forming a nonporous film.
In addition, the method of the present invention can be easily performed by sequentially adding the main component solution and the reaction solution (including B ³⁺ and halogen ions) having the same concentration of the same components in both the membrane and the particles at the same ratio while adjusting to a predetermined pH. It can also be manufactured continuously. The concentration of the above reaction solution is in the range of ± 50% by weight, the concentration of water (including acid or alkali) is in the range of ± 30% by weight, and the concentration of the halogen ion is in the range of ± 30% by weight. Can be changed.

  As the melamine resin, a butylated melamine resin or a butylated urea / melamine resin is used.

  The urethane resin may be any resin obtained by a reaction between an isocyanate curing agent and a compound having an active hydrogen such as a hydroxyl group, such as hexamethylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate.

  The curable charge transport component is preferably a material excellent in injection from the underlying charge transport layer and having a high charge transport capability. On the other hand, the use of a charge transporting monomer used for the synthesis of a polymer charge transporting material exemplified in JP-A-2001-330973 has a high track record and is extremely useful.

Laminated organic photoreceptors often increase residual potential by laminating a curable protective layer. This suppression advantageously includes a charge transport component in the material forming the curable protective layer.
For example, the charge transport component needs not to deteriorate the tough wear resistance of the curable protective layer due to its inclusion, as compared with the charge transport material blended in the charge transport layer. In addition, it is necessary that charge carriers be delivered from the lower layer of the curable protective layer with good charge transportability.
As a condition satisfying these conditions, it is effective that the material becomes a part of the crosslinked resin component, that is, a curable charge transport component is selected.

  In most cases, a charge transport material that is non-curable and has a molecular weight of less than 1000 results in embrittlement of the film, making it difficult to achieve the intended purpose. This is because this group of materials acts as a rigid plasticizer. On the other hand, the use of the thermoplastic polymer charge transport material is easily made of a resin because the material is a resin, so that embrittlement of the protective layer due to the blending is easily suppressed. However, the toughness of the protective layer in this system is not sufficient. This is because only one part of the main chain skeleton breaks and may develop into wear. On the other hand, the curable charge transport component is advantageous because it hardly progresses to wear even if a part of the resin breaks.

Generally, in order to ensure the toughness of the curable resin, it is advantageous to select a material having a high crosslinking density. However, a material having a large number of functional groups among the curable charge transporting components needs to increase the ratio of the curing agent required for crosslinking, so that the content ratio of the charge transporting components in the entire system is reduced. (Here, for convenience, the value obtained by dividing the molecular weight by the number of functional groups is defined as “equivalent” and used.) As a result, it is difficult to ensure sufficient charge transportability. It can be said that the equivalent of the curable charge transport component capable of avoiding this problem is about 200 to 500. In addition, it is important that the curable charge transport component is soluble in a solvent and is stable during film formation or over time.
In addition, it must be compatible with the charge transport material contained in the lower layer of the curable protective layer. For example, in a combination of materials having a large difference in ionization potential, they act as charge carrier trap sites with each other, resulting in deterioration of sensitivity characteristics.

In addition, the curable charge transporting component has a function of suppressing cracks and sink marks enjoyed by blending the silicone-free antifoaming agent that characterizes the present invention with the coating liquid for forming the protective layer. On the other hand, it is important in the present invention not to adversely affect the present invention.
Attempts were made to search for a curable charge transporting component satisfying these requirements, and it was found that application of the compound group according to claim 4 was particularly useful.

  That is, as the curable charge transporting component applied to the curable protective layer, it is effective to apply the compound group having the molecular structure of the above general formulas (1), (2) to (3).

In general, the charge transport component monotonously increases the sensitivity characteristics of the photoreceptor when the blending ratio is increased. Therefore, this blending ratio is adjusted in accordance with the sensitivity characteristics required in an actual electrophotographic apparatus. In many cases, it is about 10 to 50% by weight of the total solid content of the curable protective layer. However, the amount of the curable charge transporting component is desirably 1.1 times or less with respect to the curable binder serving as the curing agent. When the other component having the same functional group as the curable charge transporting component is blended, it is desirable that the equivalent ratio is 1.1 times or less with respect to the curable binder in total. This is because the performance shifts in the direction of deterioration in terms of strength and sensitivity characteristics when the amount of components that do not undergo crosslinking is increased in the curable protective layer.
The film thickness of the curable protective layer is 1 to 10 μm, preferably 3 to 8 μm.
In the present invention, the curability means a property that causes a crosslinking reaction by light irradiation (irradiation including EB, UV, etc.) or heating.

  Mixing a curable charge transport material with the curable protective layer described above has an effect of improving the charging stability. This often alleviates the difference in dielectric constant with the base. If the dielectric constants of the curable protective layer and the base are greatly different, the charge / discharge balance is lost in each layer, and it becomes difficult to ensure charging stability. As a result, an abnormal image such as an afterimage may occur. The blending of the curable charge transport material is advantageous for imparting high reliability since charging stability can be obtained in addition to improvement of sensitivity characteristics.

  As a dispersion solvent used when preparing the curable protective layer coating material, a solvent that sufficiently dissolves the components of the curable protective layer coating material and has a solubility of 1 ml / 10 mg or less with respect to the base may be selected. On the other hand, cellosolves and propylene glycols are good.

In the present invention, it is very important to use a silicone-free antifoaming agent.
Silicone-free antifoaming agents include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenols, polyhydric alcohol fatty acid esters, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene / sorbitan / fatty acid esters, Polyoxyethylene alkylamines and polyoxyethylene amides are suitable.

  These antifoaming agents are, for example, BYK-011, BYK-051, BYK-052, BYK-053, BYK-0054, BYK-350, BYK-354, BYK-355, BYK-356, BYK-359, from BYK Chemie. BYK-361, BYK-390, etc. are marketed and useful. In addition, N-type GOHSENOL and G-type GOHSENOL are marketed by Nippon Kagaku, and Dappo SN-348, Dappo SN-357, Dappo SN-368, SN deformer 111, SN deformer JK, SN deformer 5013, etc. are marketed by Sannopco. These can also be used.

  The appropriate content of the silicone-free additive is about 0.1% to 6% by weight based on the solid content of the paint. When the amount is less than 0.1% by weight, the effect of preventing cracking due to the addition is small, so it is desirable to make it more. If it exceeds 6% by weight, it may be a residual charge accumulation factor, so it is better not to exceed this. In the present invention, these antifoaming agents are less likely to migrate from the coating layer to the vicinity of the coating layer surface during coating and heating and drying, and thus are not necessary, but the protective layer can be used depending on the storage time of the photoreceptor or long-term use. Since the ratio of bleeding out from the toner is low, it can be effectively used as a trace (in the case of analysis) for checking whether or not the photosensitive member is produced by the production method of the present invention.

  Examples of the method for forming the curable protective layer include an immersion method, a spray coating method, a ring coating method, a roll coater method, a gravure coating method, a nozzle coating method, and a screen printing method. In many cases, since the pot life of the coating liquid is not long, a means capable of coating a necessary amount with a small amount of paint is advantageous in consideration of the environment and cost. Of these, the spray coating method and the ring coating method are preferred.

  When the curable protective layer coating solution coating is heat-dried, it is important that the coating does not become tacky. Thereby, insufficient curing and non-uniform curing can be suppressed.

If the curing temperature is too high or too low, a curing failure will occur, so this setting also affects the stabilization of quality. In order to proceed with sufficient curing, it is better to avoid sudden volatilization of the solvent. On the other hand, if the curing rate is too slow, the curable protective layer itself has a film thickness unevenness, cracks, or alteration of the base such as crystallization of the charge transport material, so it is necessary to heat at an appropriate temperature.
The specific set temperature needs to be adjusted depending on the material used, but the endothermic peak temperature of the protective layer coating solution is X (° C), the boiling point of the coating solution solvent is Y (° C), and the protective layer is formed. When the maximum heating and drying temperature is Z (° C.), the curing should proceed at a set temperature that satisfies the following conditions.

ここで保護層塗工液の吸熱ピーク温度はＤＳＣ測定装置によって得られる値である。本発明では理学電機社製示差走査熱量計 Ｔｈｅｒｍｏｐｌｕｓ ＤＳＣ８２３０を用いて計測している。測定は開放型アルミパンを用いて、４０℃から２００℃の温度範囲を１０℃／ｍｉｎの走査速度で昇温したときに得られるファーストスキャン時のＤＳＣカーブを採用した。

Here, the endothermic peak temperature of the protective layer coating solution is a value obtained by a DSC measuring apparatus. In the present invention, the measurement is performed using a differential scanning calorimeter Thermoplus DSC8230 manufactured by Rigaku Corporation. For the measurement, an open-type aluminum pan was used, and a DSC curve at the time of first scan obtained when the temperature range from 40 ° C. to 200 ° C. was raised at a scanning rate of 10 ° C./min was adopted.

In order to obtain a uniform curable protective layer for various underlayers, it is more preferable that the maximum heating temperature is not higher than the glass transition temperature of the charge transport layer.
As the crosslinking reaction proceeds, the solvent often volatilizes even when the heating temperature is lower than the boiling point of the solvent. The diffusion of the solvent into the atmosphere and the exothermic heat of crosslinking appear to promote volatilization.
In the cured film of the curable protective layer in which the retention of residual solvent and curing failure are suppressed to a sufficient extent, no endothermic peak is observed even when a DSC curve is obtained in the same manner as before. Therefore, it is desirable to form a curable protective layer exhibiting this feature.

  The thickness of the curable protective layer is suitably about 1 to 10 μm, preferably about 2 to 5 μm.

The process cartridge of the present invention uses the toner of the present invention, integrally supports at least one means selected from a photosensitive member, a developing means, a charging means, and a cleaning means, and is a process that is detachable from the main body of the image forming apparatus. It is a cartridge.
FIG. 4 shows a schematic configuration of an image forming apparatus having the process cartridge of the present invention.
In the figure, (101) shows the entire process cartridge, (111) shows the photoreceptor of the present invention, (20) shows charging means, (40) shows developing means, and (60) shows cleaning means. The process cartridge is configured to be detachable from a main body of an image forming apparatus such as a copying machine or a printer.

Hereinafter, the present invention will be described by way of examples.
A measurement method according to the present invention will be described.
(1) Film thickness measurement The film thickness was measured at intervals of 1 cm in the longitudinal direction of the photosensitive drum with an eddy current type film thickness measuring instrument (FISCHER SCOPE mms, manufactured by Fischer), and the average value thereof was defined as the photosensitive layer thickness.

(2) Surface Roughness Measurement of Photoreceptor The surface of a drum-shaped photoreceptor is measured with a stylus type surface roughness meter (Surfcom, Tokyo Seimitsu Co., Ltd.) equipped with a Tokyo Seimitsu pickup E-DT-S02A. Rmax (JIS-'82 standard) was measured.

(3) Cleaning blade breakage rank After the end of the durability test, the cleaning blade mounted on the testing machine is taken out, and the scanning depth is measured with an ultra-deep shape measuring microscope (VK-8500, manufactured by Keyence Corporation) equipped with a 100x objective lens. Was set to 5 μm (in increments of 0.01 μm), and the edge surface was observed from directly above and from the side.
(Cleaning blade damage evaluation criteria)
5: No chipping of the blade edge was observed and good.
4: Very little chipping of blade edge is observed, but good.
3: The blade edge chipping is observed only slightly, but is substantially good.
2: Slight chipping of the blade edge is observed, but there is substantially no problem.
1: Chipping of the blade edge is observed, which causes a problem.

(4) Photoconductor surface potential measurement A modified developing unit equipped with a probe of a surface potential meter (Trek Model 344, manufactured by Trek) was attached to the developing unit in the copying machine, and the surface potential at the center of the photoconductor was measured.

Example 1
By coating and drying an undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution in the following composition on an aluminum drum having a wall thickness of 0.8 mm and φ100 mm, 3.0 μm. An undercoat layer, a 0.4 μm charge generation layer, and a 25 μm charge transport layer were formed. Next, a coating solution for the outermost surface layer of the photoreceptor was applied by spraying, and the outermost surface layer of 5 μm was provided to obtain the electrophotographic photoreceptor of the present invention.

[Coating liquid for undercoat layer]
Alkyd resin (Beccosol 1307-60-EL, manufactured by Dainippon Ink and Chemicals) 10 parts by weight Melamine resin (Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals) 7 parts by weight Titanium oxide (CR-EL Ishihara Sangyo) 40 parts by weight Methyl ethyl ketone 200 parts by weight

[Coating liquid for charge generation layer]
Titanyl phthalocyanine (Ricoh Co., Ltd.) 20 parts by weight Polyvinyl alcohol (ESREC B BX-1, Sekisui Chemical Co., Ltd.) 10 parts by weight Methyl ethyl ketone 100 parts by weight

[Coating liquid for charge transport layer]
Polycarbonate resin (Panlite TS-2050, manufactured by Teijin Chemicals Ltd.) 10 parts by weight 10 parts by weight of low molecular charge transport material having the following structure

テトラヒドロフラン ７９重量部
１％シリコーンオイル（ＫＦ５０−１００ＣＳ信越化学工業社製）
テトラヒドロフラン溶液 １重量部

Tetrahydrofuran 79 parts by weight 1% silicone oil (KF50-100CS Shin-Etsu Chemical Co., Ltd.)
1 part by weight of tetrahydrofuran solution

[Coating liquid for curable protective layer]
3 parts by weight of a curable charge transport material having a reactive hydroxyl group with the following structure

シリコーンフリー消泡剤（ＢＹＫ−０５４、ビックケミー社製） １重量部
（固形分：０．２５重量部）
熱硬化性樹脂単量体
（スーパーベッカミン Ｇ−８２１−６０，大日本インキ化学工業製）１２重量部
（固形分：７．２重量部）
プロピレングリコールモノメチルエーテル ９４重量部
硬化型保護層の硬化条件は１５０℃３０分とした。

Silicone-free antifoaming agent (BYK-054, manufactured by Big Chemie) 1 part by weight
(Solid content: 0.25 parts by weight)
Thermosetting resin monomer (Super Becamine G-821-60, manufactured by Dainippon Ink & Chemicals) 12 parts by weight
(Solid content: 7.2 parts by weight)
94 parts by weight of propylene glycol monomethyl ether The curing conditions for the curable protective layer were 150 ° C. and 30 minutes.

Comparative Example 1
An electrophotographic photoreceptor was obtained in the same manner as in Example 1 except that the silicone-free antifoaming agent was not added to the coating liquid for curable protective layer of Example 1.

[Spray coating conditions for outermost surface layer of photoreceptor in Example 1 and Comparative Example 1]
Coating liquid discharge rate: 10 ml / min
Coating liquid discharge pressure: 2.4 kgf / cm ²
Rotating speed of coated drum: 120rpm
Coating speed: 28mm / sec
Distance between spray head and coated drum: 5cm
Number of coatings: 2 times

  The high-speed electron in which the process time until the image exposure portion of the photosensitive member reaches the sleeve portion of the developing means is modified to 95 msec after mounting the electrophotographic photosensitive member of Example 1 and Comparative Example 1 manufactured as described above for mounting. Mounted on a photographic device (Imagio Neo 1050 Pro, manufactured by Ricoh Co., Ltd.), a total of 10,000 copies under the condition of printing 999 continuous text and graphic image patterns with a pixel density of 600 dpi x 600 dpi and an image density of 6% Copied and printed on paper (Ricoh's My Paper). Pure toner and developer were used. As the charging means of the electrophotographic apparatus, a scorotron charger attached to the apparatus was used as it was. A circuit for controlling the process state of the electrophotographic apparatus (process control) was activated and tested.

The test environment was 24 ° C./54% RH.
The surface roughness Rmax of the photoreceptor surface was measured before and after the test. Further, the evaluation of damage to the cleaning blade after completion of the test was evaluated.
The test results are shown in Table 1.

  The surface of the photoreceptor containing the silicone-free antifoaming agent is smooth before and after the test, and the cleaning blade is not damaged even after printing. On the other hand, in Comparative Example 1, spinous protrusions were observed on the surface before the test, and the cleaning blade was damaged by the printing process. It is interpreted that the deterioration of the cleaning blade is suppressed by adding a silicone-free antifoaming agent to the curable protective layer.

Example 2
By coating and drying an undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution in the following composition on an aluminum drum having a wall thickness of 0.8 mm and φ30 mm, 3.5 μm. An undercoat layer, a 0.3 μm charge generation layer, and a 25 μm charge transport layer were formed. Next, a coating solution for the outermost surface layer of the photoreceptor was applied by spraying, and the outermost surface layer of 5 μm was provided to obtain the electrophotographic photoreceptor of the present invention.

[Coating liquid for undercoat layer]
Alkyd resin (Beccosol 1307-60-EL, manufactured by Dainippon Ink and Chemicals)
10 parts by weight melamine resin (Super Becamine G-821-60, manufactured by Dainippon Ink & Chemicals, Inc.)
7 parts by weight Titanium oxide (CR-EL manufactured by Ishihara Sangyo Co., Ltd.) 40 parts by weight Methyl ethyl ketone 200 parts by weight

[Coating liquid for charge generation layer]
Titanyl phthalocyanine (Ricoh Co., Ltd.) 20 parts by weight Polyvinyl alcohol (ESREC B BX-1, Sekisui Chemical Co., Ltd.) 10 parts by weight Methyl ethyl ketone 100 parts by weight

[Coating liquid for charge transport layer]
Polycarbonate resin (Panlite TS-2050, manufactured by Teijin Chemicals Ltd.) 10 parts by weight 10 parts by weight of low molecular charge transport material having the following structure

テトラヒドロフラン ７９重量部
１％シリコーンオイル（ＫＦ５０−１００ＣＳ信越化学工業社製）
テトラヒドロフラン溶液 １重量部

Tetrahydrofuran 79 parts by weight 1% silicone oil (KF50-100CS Shin-Etsu Chemical Co., Ltd.)
1 part by weight of tetrahydrofuran solution

[Coating liquid for curable protective layer]
3 parts by weight of a curable charge transport material having a reactive hydroxyl group with the following structure

シリコーンフリー消泡剤（ＢＹＫ−０５４、ビックケミー社製） １重量部
（固形分：０．２５重量部）
熱硬化性樹脂単量体
（スーパーベッカミン Ｇ−８２１−６０，大日本インキ化学工業製） １２重量部
（固形分：７．２重量部）
プロピレングリコールモノメチルエーテル ９４重量部
硬化型保護層の硬化条件は１５０℃３０分とした。

Silicone-free antifoaming agent (BYK-054, manufactured by Big Chemie) 1 part by weight
(Solid content: 0.25 parts by weight)
Thermosetting resin monomer (Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals) 12 parts by weight
(Solid content: 7.2 parts by weight)
The curing conditions for 94 parts by weight of the curable protective layer of propylene glycol monomethyl ether were 150 ° C. and 30 minutes.

Comparative Example 2
Instead of the silicone-free antifoaming agent in the coating liquid for curable protective layer of Example 1, 2.1 parts by weight (solid content: 0.24 parts by weight) of a silicone-based antifoaming agent (BYK-080A, manufactured by Big Chemie) The electrophotographic photosensitive member was obtained in the same manner as Example 1 except for the addition.

[Spray coating conditions for outermost surface layer of photoreceptor in Example 2 and Comparative Example 2]
Coating liquid discharge rate: 10 ml / min
Coating liquid discharge pressure: 2.4 kgf / cm ²
Rotating speed of coated drum: 120rpm
Coating speed: 28mm / sec
Distance between spray head and coated drum: 5cm
Number of coatings: 2 times

After the electrophotographic photoreceptors of Example 1 and Comparative Example 1 produced as described above were used for mounting, the process time until the image exposure portion of the photoreceptor reached the sleeve of the developing means was modified to 95 msec. Mounted on a device (Imagio MF200, manufactured by Ricoh Co., Ltd.), 10,000 sheets of copy paper (total of 999 sheets of text and graphic image patterns with a pixel density of 600 dpi × 600 dpi and an image density of 6% are printed continuously) Copied and printed on Ricoh's My Paper. Pure toner and process cartridges were used. As the charging means of the electrophotographic apparatus, a scorotron charger attached to the apparatus was used as it was. The circuit (process control) for controlling the process state of the electrophotographic apparatus was released and the test was performed.
The test environment was 24 ° C./54% RH.
After completion of the test, the photoconductor, process cartridge, and electrophotographic apparatus are stored for one day in an environment of 35 ° C. and 80%, and the test chart (Ricoh test chart S-3) is copied and tested in this environment. The amount of wear and the resolution of the photoreceptor surface were evaluated.

  In Example 2 in which a silicone-free antifoaming agent was blended in the curable protective layer, a higher resolution result was obtained as compared with Comparative Example 2 using a silicone-based antifoaming agent. In order to suppress resolution degradation, it is judged to be advantageous to select a silicone-free antifoaming agent.

Example 3
By coating and drying an undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution on a 0.8 mm thick aluminum drum of the following composition in order, 3.5 μm An undercoat layer, a 0.2 μm charge generation layer, and a 27 μm charge transport layer were formed. Next, a coating solution for the outermost surface layer of the photosensitive member was applied by ring coating, and a 5 μm outermost surface layer of the photosensitive member was provided to obtain the electrophotographic photosensitive member of the present invention.

[Coating liquid for undercoat layer]
Alkyd resin (Beccosol 1307-60-EL, manufactured by Dainippon Ink and Chemicals)
10 parts by weight melamine resin (Super Becamine G-821-60, manufactured by Dainippon Ink & Chemicals, Inc.)
7 parts by weight Titanium oxide (CR-EL manufactured by Ishihara Sangyo Co., Ltd.) 40 parts by weight Methyl ethyl ketone 200 parts by weight

[Coating liquid for charge generation layer]
Titanyl phthalocyanine (Ricoh Co., Ltd.) 20 parts by weight Polyvinyl alcohol (ESREC B BX-1, Sekisui Chemical Co., Ltd.) 10 parts by weight Methyl ethyl ketone 100 parts by weight

[Coating liquid for charge transport layer]
Polycarbonate resin (Panlite TS-2050, manufactured by Teijin Chemicals Ltd.) 7 parts by weight 10 parts by weight of low molecular charge transport material having the following structure

テトラヒドロフラン ７９重量部
１％シリコーンオイル（ＫＦ５０−１００ＣＳ信越化学工業社製）
テトラヒドロフラン溶液 １重量部

Tetrahydrofuran 79 parts by weight 1% silicone oil (KF50-100CS Shin-Etsu Chemical Co., Ltd.)
1 part by weight of tetrahydrofuran solution

[Coating liquid for curable protective layer]
Silicone-free antifoaming agent (BYK-054, manufactured by Big Chemie) 2 parts by weight
(Solid content: 0.5 part by weight)
20 parts by weight of HDI polyisocyanate (Coronate HX, manufactured by Nippon Polyurethane Co., Ltd.) 28 parts by weight of a crosslinkable charge transport material having the following structure

エチルソルブ ２００重量部

200 parts by weight of ethylsolve

Example 4
A photoconductor was prepared in the same manner as in Example 3 except that the content of the silicone-free antifoaming agent contained in the curable protective layer of Example 3 was changed to 0.2 parts by weight (solid content: 0.05 parts by weight). Obtained.

Example 5
A photoconductor was prepared in the same manner as in Example 3 except that the content of the silicone-free antifoaming agent contained in the curable protective layer of Example 3 was changed to 0.4 parts by weight (solid content 0.1 parts by weight). Obtained.

Example 6
A photoconductor was obtained in the same manner as in Example 3 except that the content of the silicone-free antifoaming agent contained in the curable protective layer of Example 3 was changed to 8 parts by weight (solid content 2 parts by weight).

Example 7
A photoconductor was obtained in the same manner as in Example 3 except that the content of the silicone-free antifoaming agent contained in the curable protective layer of Example 3 was changed to 12 parts by weight (solid content 3 parts by weight).

A high speed electrophotographic apparatus in which the process time until the image exposure portion of the photoconductor reaches the sleeve portion of the developing means is modified to 95 msec after the electrophotographic photoconductors of Examples 3 to 6 manufactured as described above are used for mounting. (Imagio Neo 1050 Pro manufactured by Ricoh Co., Ltd.), 1 million sheets of copy paper under the conditions of printing 999 continuous text and graphic image patterns with a pixel density of 600 dpi × 600 dpi and an image density of 6% (copy paper ( Copied and printed on Ricoh's My Paper. Pure toner and developer were used. As the charging means of the electrophotographic apparatus, a scorotron charger attached to the apparatus was used as it was. A circuit for controlling the process state of the electrophotographic apparatus (process control) was activated and tested.
The test environment was 24 ° C./54% RH.
After completion of the test, the photosensitive member exposed portion potential (VL) when the black pattern image was written and the cleaning blade were evaluated for damage.
The test results are shown in Table 3.

  From the test results of Examples 3 to 6, the antifoaming agent is added in an appropriate amount. The content is suitably 0.2% by weight or more and less than 6% by weight based on the solid content of the curable protective layer.

1 is a schematic view of an image forming apparatus using an electrophotographic system according to the present invention. 1 is a cross-sectional view schematically showing an example of an electrophotographic photosensitive member in the present invention. It is sectional drawing which shows typically another example of the electrophotographic photoreceptor which has a layer structure in this invention. It is a figure which shows one example of the process cartridge of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electrophotographic photosensitive member 2 ... Charging means 3 ... Image exposure means 4 ... Developing means 5 ... Transfer means 6 ... Charge removal charger 7 ... Cleaning means 8 ... Static elimination Means 9 ... Fixing means 10 ... Paper feed tray 11 ... Transfer target 12 ... Paper discharge tray 13 ... Hard copy 20 ... Charging means 21 ... Conductive support 22 ..Charge generation layer 23... Charge transport layer 24... Curable protective layer 25... Subbing layer 40... Developing means 60. 111..Photoconductor

Claims (9)

  In a method for producing an electrophotographic photosensitive member, in which a curable protective layer is further laminated on a photosensitive layer comprising a charge generation layer and a charge transport layer on a conductive support, a curable charge transport component and a curable binder component are formed on the photosensitive layer. And a method for producing an electrophotographic photosensitive member, comprising: applying a coating solution for forming a protective layer containing a silicone-free antifoaming agent, drying the solution, and causing a crosslinking reaction in the protective layer.   The silicon-free antifoaming agent is at least polyoxyethylene alkyl ethers, polyoxyethylene alkylphenols, polyhydric alcohol fatty acid esters, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene / sorbitan / fatty acid esters, 2. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the method is one or more of polyoxyethylene alkylamines and polyoxyethylene amides.   3. The electrophotographic photoreceptor according to claim 1, wherein the content of the silicon-free antifoaming agent is 0.1 wt% or more and less than 6 wt% of the total solid content in the coating liquid. Production method. The electrophotographic photosensitive member according to any one of claims 1 to 4, wherein the curable charge transporting component contains at least one of the compounds represented by the following general formulas (1) to (3).

In the formula, R ₂ is a hydrogen atom, an alkyl group, a fluorine atom, a cyano group, an alkyl group substituted with a phenyl group or a halogen atom, or an alkyl group substituted with a phenyl group substituted with a C _{1 to} C ₄ alkyl group. , an aryl group, a fluorine atom, a cyano group, a phenyl group, or an aryl group substituted by a halogen atom, an aryl group substituted with a phenyl group substituted with an alkyl group of C ₁ ~C _4, R ₃ is a hydrogen atom , alkyl group, a fluorine atom, a cyano group, a phenyl group or a halogen atom-substituted alkyl group, C ₁ -C ₄ alkyl group substituted by an alkyl group substituted with a phenyl group, an aryl group, a fluorine atom, a cyano group, a phenyl group, or an aryl group substituted by a halogen atom, C ₁ -C ₄ aryl group substituted with a phenyl group substituted with an alkyl group, c Represents a Gen atom, R ₃ represents a hydrogen atom, Ar _1, Ar ₂ represents an aryl group, an aryl group substituted with a halogen atom or an alkyl group. However, the case where R ₃ is a hydrogen atom and Ar ₁ and Ar ₂ are p-tolyl groups is excluded.
X represents any of the following (a) to (d).
(A) an alkylene group (b) a fluorine atom, a cyano group, a phenyl group, or a halogen atom or a C ₁ -C ₅ alkylene group (c) an arylene group substituted by a phenyl group substituted with an alkyl group (d) below Group represented by general formula (4)

{In the formula, Y is -O -, - S -, - SO -, - SO 2 -, - CO- and represent divalent groups below.

(Wherein R ₅ and R ₆ are a hydrogen atom, an alkyl group, an alkyl group having a substituent defined in (c), an alkoxy group, a halogen atom, an aryl group, and a substituent defined in (e) above) Represents an aryl group having an amino group, an amino group, a nitro group, or a cyano group, and p, q, r, and s represent an integer of 1 to 12)}

R ₇ and R ₈ represent a substituted or unsubstituted aryl group. R ₇ and R ₈ may be the same or different.
The arylene group represented by Ar ₃ , Ar ₄ and Ar ₅ includes the same divalent group as the aryl group as R ₅ and R ₆ , which may be the same or different.
X is the same as that mentioned in the general formula (2).

R ₉ and R ₁₀ represent a substituted or unsubstituted aryl group. R ₉ and R ₁₀ may be the same or different.
In addition, the arylene group represented by Ar ₆ and Ar ₇ includes the same divalent group of an aryl group as R ₉ and R ₁₀ , which may be the same or different.
X is the same as that mentioned in the general formula (2).   The method for producing an electrophotographic photosensitive member according to any one of claims 1 to 4, wherein the curable binder component is a melamine resin, a urethane resin, or an acrylic resin.   5. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the curable binder component is a vitreous forming component by a sol-gel method.   An electrophotographic photosensitive member obtained by the production method according to claim 1.   A process cartridge on which the electrophotographic photosensitive member according to claim 7 is mounted. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 7 or the process cartridge according to claim 8.

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