JP2008304702A - Electrophotographic photoreceptor, image forming method using the same, image forming apparatus and process cartridge for image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor that has a crosslinked surface layer formed by using a specified radical polymerizable compound, and stably forms an image with less fluctuation in optical attenuation properties, while maintaining high abrasion resistance even if making the crosslinked surface layer thick; and also to provide an image forming method, image forming apparatus and process cartridge for the image forming apparatus, which has achieved high quality for a long period of time by using such a photoreceptor as having high endurance, high stability and long life. <P>SOLUTION: The electrophotographic photoreceptor with a photosensitive layer on an electrically conductive support has a charge-transportable crosslinked surface layer obtained by curing a compound of a specified structure on the surface of the photoreceptor. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member having extremely high wear resistance, and also relates to an electrophotographic photosensitive member excellent in potential light attenuation characteristics and its stability. The present invention also relates to an image forming method, an image forming apparatus, and a process cartridge for the image forming apparatus using the long-life, high-sensitivity electrophotographic photosensitive member.

  In recent years, organic photoreceptors (OPC) have been widely used in copying machines, facsimile machines, laser printers, and composite machines in place of inorganic photoreceptors because of their good performance and various advantages. This is because, for example, (1) optical characteristics such as the light absorption wavelength range and the amount of absorption, (2) electrical characteristics such as high sensitivity and stable charging characteristics, and (3) material selection range (4) Ease of manufacturing, (5) Low cost, (6) Non-toxicity, and the like. On the other hand, the diameter of the photoconductor has recently been reduced due to the downsizing of the image forming apparatus, and the high speed of the machine and the maintenance-free movement have been added to increase the durability of the photoconductor. From this point of view, organophotoreceptors are generally soft because the charge transport layer is mainly composed of a low molecular charge transport material and an inert polymer. There is a drawback that wear is likely to occur due to a mechanical load. In addition, due to the demand for higher image quality, the cleaning blade is required to increase its rubber hardness and contact pressure for the purpose of improving the cleaning property as the particle size of the toner particles is reduced. This also promotes wear of the photoreceptor. It is a factor. Such abrasion of the photoreceptor deteriorates electrical characteristics such as sensitivity deterioration and chargeability, and causes abnormal images such as image density reduction and background stains. Further, scratches where wear is locally generated cause streak-like stain images due to poor cleaning. Therefore, attempts to improve the wear resistance of the organic photoreceptor have been studied from various directions.

  Among them, those having a cross-linked surface layer obtained by curing a polyfunctional radical curable monomer (see, for example, Patent Document 1) can use a monomer having a large amount of functional groups to form a dense three-dimensional network structure and high wear resistance. It is noted that a cured film can be instantly formed by light, heat, and radiation, and that a cured material does not require an acid or base catalyst for the curing reaction and does not adversely affect electrical characteristics. Furthermore, in order to improve the electrical properties of the crosslinked surface layer, a charge transport material having a radical polymerizable functional group is used in combination, and the charge transport structure is fixed in the crosslinked structure (see, for example, Patent Documents 2 and 3). These technologies were expected to achieve both wear resistance and charge transportability.

  The charge mobility in these cross-linked surface layers greatly affects the light attenuation characteristics of the photoreceptor surface potential. However, compared with a normal charge transport layer, the charge mobility in the cross-linked surface layer is poor and the light attenuation property is deteriorated. If the film thickness of the cross-linked surface layer is small, the effect is small. However, if the film thickness is increased in order to extend the life of the photoconductor, the light attenuation characteristics deviate from the practical range due to the effect. Life extension was not achieved.

On the other hand, charge transport materials having a large number of radically polymerizable functional groups have been proposed so far, but no material satisfying the wear resistance and sufficient charge transport property of the crosslinked film has been found.
In addition, the characteristics vary depending on the type of charge transport material having a radical polymerizable functional group, and the selection thereof is very important.
The reason why the characteristics change greatly depending on the type of the charge transport material is not clear, but it is expected that the uniformity of the cross-linked film, the influence on the thermal characteristics, the electrical influence by the functional group, etc. are different for each material. In particular, in the case of a crosslinked surface layer formed by photocuring, it is strongly affected by light irradiation. Usually, ultraviolet rays are used as a light source for photocuring, but the charge transport material is partially decomposed by ultraviolet rays, and various decomposition products are generated depending on its structure. Some of these decomposition products remain in the cross-linked surface layer and are considered to cause various characteristic deteriorations. Therefore, the decomposition product generated varies depending on the structure of the charge transport material, and therefore, it is expected that a large characteristic difference is caused depending on the type of the charge transport material.
As described above, by increasing the thickness of the cross-linked surface layer, it is expected to further extend the life of the photoreceptor, but for that purpose, it has excellent light attenuation characteristics that can sufficiently reduce the developed portion potential after exposure. In the present situation, formation of a crosslinked surface layer having an excellent charge transporting property and an excellent wear resistance enough to make it possible has not been achieved.

Japanese Patent No. 3262488 Japanese Patent No. 3194392 JP 2000-66425 A JP 2006-3863 A Japanese Patent No. 2896823 JP 2006-71856 A

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photosensitive member that is excellent in wear resistance, has a fast light attenuation of surface potential, and is stable, highly durable, and has a high performance. More specifically, it has a cross-linked surface layer formed using a specific radical polymerizable compound, and even if the cross-linked surface layer is thick, there is little fluctuation in light attenuation characteristics while maintaining high wear resistance, and a stable image. It is an object to provide an electrophotographic photosensitive member that can be formed.
Another object of the present invention is to provide an image forming method, an image forming apparatus, and a process cartridge for an image forming apparatus that use such a highly durable and highly stable long-life photoconductor and realize high image quality over a long period of time.

As a result of intensive studies, the present inventors have found that the above object can be achieved by the following present invention, and have completed the present invention.
(1) “In an electrophotographic photosensitive member having a photosensitive layer on a conductive support, the photosensitive member has a charge transport cross-linked surface layer formed by curing at least a compound represented by the following general formula (A) on the surface. An electrophotographic photoreceptor characterized by:

（式中、Ｒ_１〜Ｒ_４は、それぞれ水素原子又はメチル基を表わし、Ｒ_５〜Ｒ_１７はそれぞれ水素原子、炭素数１〜４のアルキル基を表わす。）」、
（２）「前記架橋表面層が、少なくとも前記一般式（Ａ）で表わされる化合物と、更にラジカル重合性官能基を有するモノマーとを含有する塗工層を硬化させて形成されたものであることを特徴とする前記第（１）項に記載の電子写真感光体」、
（３）「前記架橋表面層が、硬化されていない感光層の上に形成されていることを特徴とする前記第（１）項又は第（２）項に記載の電子写真感光体」、
（４）「前記架橋表面層が、光のエネルギーを用いた手段で硬化されたものであることを特徴とする前記第（１）項乃至第（３）項のいずれかに記載の電子写真感光体」、
（５）「前記硬化されていない感光層が、導電性支持体上に少なくとも電荷発生層と電荷輸送層を順次積層した構成をと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」、
（６）「電子写真感光体を用いる画像形成方法において、該電子写真感光体が前記第（１）項乃至第（５）項のいずれかに記載の電子写真感光体であることを特徴とする画像形成方法」、
（７）「少なくとも帯電手段、露光手段、現像手段、転写手段、及び電子写真感光体を具備してなる画像形成装置において、該電子写真感光体が前記第（１）項乃至第（５）項のいずれかに記載の電子写真感光体であることを特徴とする画像形成装置」、
（８）「前記第（１）項乃至第（５）項のいずれかに記載の電子写真感光体と、更に帯電手段、露光手段、現像手段、転写手段、クリーニング手段、除電手段から選択される少なくとも１つの手段とが一体となり、画像形成装置と着脱自在であることを特徴とするプロセスカートリッジ」。

(Wherein R _{1 to} R ₄ each represent a hydrogen atom or a methyl group, and R _{5 to} R ₁₇ each represent a hydrogen atom and an alkyl group having 1 to 4 carbon atoms) ”
(2) “The crosslinked surface layer is formed by curing a coating layer containing at least the compound represented by the general formula (A) and a monomer having a radical polymerizable functional group. The electrophotographic photosensitive member according to item (1), wherein:
(3) "The electrophotographic photosensitive member according to item (1) or (2), wherein the crosslinked surface layer is formed on an uncured photosensitive layer",
(4) The electrophotographic photosensitive member according to any one of (1) to (3), wherein the crosslinked surface layer is cured by means using light energy. body",
(5) The items (1) to (4), wherein the uncured photosensitive layer has a structure in which at least a charge generation layer and a charge transport layer are sequentially laminated on a conductive support. The electrophotographic photosensitive member according to any one of items
(6) “In an image forming method using an electrophotographic photosensitive member, the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of (1) to (5)”. Image forming method ",
(7) “In an image forming apparatus comprising at least a charging means, an exposure means, a developing means, a transfer means, and an electrophotographic photosensitive member, the electrophotographic photosensitive member is the above-mentioned items (1) to (5). An image forming apparatus characterized by being an electrophotographic photosensitive member according to any one of
(8) “Selected from the electrophotographic photosensitive member according to any one of the above items (1) to (5), and further, a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a static elimination unit. A process cartridge which is integrated with at least one means and is detachable from an image forming apparatus.

  A crosslinked surface layer containing a charge transportable cured product formed by applying a coating solution containing at least the polymerizable compound represented by the general formula (A) of the present invention to the surface of the photosensitive layer and then curing the coating solution. By using the electrophotographic photosensitive member, an electrophotographic photosensitive member having high wear resistance, fast light attenuation of the surface potential, stable high durability and high performance is realized. Therefore, by using this photoreceptor, it is possible to provide a high-performance, reliable and easy-to-maintain image forming method, an image forming apparatus, and a process cartridge for the image forming apparatus that can provide higher-quality images over a long period of time.

Hereinafter, the present invention will be described in detail.
In the present invention, it has been found that by using the radically polymerizable compound of the general formula (A) in the formation of the crosslinked surface layer, both wear resistance and charge transportability can be achieved in a high dimension.

<Reasons for achieving both wear resistance and charge transportability>
Conventionally, it has been known that a crosslinked surface layer made of a radically curable composition can form a dense three-dimensional network structure, and thereby exhibits high wear resistance. As described in Japanese Patent No. 3262488 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2006-227761, the factor governing wear resistance is to increase the amount of radical curable functional groups in the curable composition. Importantly, for example, in the case of an acrylic group, by using a monomer having a small acrylic equivalent (a value obtained by dividing the monomer molecular weight by the number of functional groups), a denser three-dimensional cross-linked structure can be formed and high wear resistance can be achieved. It is disclosed. It is also effective to improve the wear resistance by using a monomer having a large number of functional groups, for example, a monomer having three or more functional groups, and further a hexafunctional monomer. This is because the probability of increasing increases.
Accordingly, in order to develop excellent wear resistance, a radical polymerizable group concentration of a certain level or more is required. Usually, only the radical polymerizable group concentration of the radical polymerizable compound having charge transporting property is not sufficient, and the polyfunctional radical polymerizable monomer is mixed to satisfy the requirement.

On the other hand, with regard to charge transportability, it is at least necessary that the characteristics of the charge transport material itself be excellent, but by itself, it is greatly inferior to a conventional non-crosslinked charge transport layer. Although the cause of this is not well understood, it is expected that this is caused by the thermal mobility of the crosslinked film, the uniform dispersibility of the charge transport material, the incorporation of impurities at the time of forming the crosslinked film, the occurrence of film defects, and the like.
In particular, when UV curing is applied as a polymerization method, the charge transport material is decomposed by light irradiation, and many impurities are generated.
Taking these into consideration, the radical polymerizable compounds having charge transporting properties so far were reviewed from the following viewpoint, and the radical polymerizable compounds were designed.
-Less degradation during UV irradiation.
-The basic skeleton has excellent charge transport properties.
-The thermal mobility of the radical reactive group site of the polymerizable compound is high.
In order to prevent non-uniformity of the crosslinked film composition, it has a radical reactive group sufficient to obtain a sufficient crosslinking density even with a single composition.
-The crystallinity is low and a transparent uniform coating film can be formed.
With the intention of these, the polymerizable compound of the general formula (A) was newly designed and synthesized, and its characteristics were evaluated. As a result, it was found that a crosslinked surface layer having both excellent wear resistance and charge transportability could be formed. I found it. It is unclear which factor was effective, but it is considered that the characteristics were superior compared to the conventional cross-linked surface layer by combining the factors.

<Regarding the curable composition>
Next, the curable composition for forming the crosslinked surface layer of the present invention and the components of the cured product will be described.
The present invention relates to an electrophotographic photoreceptor having a crosslinked surface layer containing at least a charge transporting radical curable composition on a conductive support, wherein the charge transporting radical curable composition is at least represented by the following general formula (A): The electrophotographic photosensitive member is characterized in that it is formed by applying a coating solution containing a radical polymerizable compound represented by the formula (1) to the surface of the photosensitive layer and then radical curing.

The present invention uses a radical polymerizable compound having the structure of the general formula (A) for forming the radical curable composition, and is cured by light, heat, or electron beam energy, so that Introduced into the cured structure. During this curing, the central structural unit excluding the polymerization reactive group portion of the general formula (A) is fixed without being decomposed, and the cured surface layer is measured by MS spectrum measurement by pyrolysis GC analysis, characteristic absorption measurement by infrared spectroscopy analysis, etc. It can be confirmed with. The central structural unit of the general formula (A) is 40 to 100% by mass, preferably 50 to 100% by mass, based on the total amount of the cured product. When the central structural unit of the general formula (A) in the cured product is less than 40% by mass, it is impossible to achieve charge transport characteristics that can cope with a thick film and image degradation suppression due to potential fluctuation. In addition, the polymerizable compound of the general formula (A) can form a crosslinked surface layer having excellent wear resistance without mixing other monomers, and can be added with a polymerization initiator, a leveling agent, an antioxidant, or the like. From the viewpoint of charge transporting properties, it is preferable to use almost 100% composition excluding the agent.
The radical polymerizable compound is a compound represented by the general formula (A).

（式中、Ｒ_１〜Ｒ_４は、それぞれ水素原子又はメチル基を表わし、Ｒ_５〜Ｒ_１７はそれぞれ水素原子、炭素数１〜４のアルキル基を表わす。）

(In the formula, R _{1 to} R ₄ each represent a hydrogen atom or a methyl group, and R _{5 to} R ₁₇ each represent a hydrogen atom and an alkyl group having 1 to 4 carbon atoms.)

  The radically polymerizable compound represented by the general formula (A) is a novel compound and can be synthesized, for example, by the following production method.

一般式（Ａ）で表わされるラジカル重合性化合物としては、以下のものが例示されるが、これらの化合物に限定されるものではない。

Although the following are illustrated as a radically polymerizable compound represented by general formula (A), It is not limited to these compounds.

  The polymerizable compound of the general formula (A) suitably used in the present invention is 40 to 100% by mass, preferably 50 to 100% by mass, based on the total amount of the curable constituent material. When these polymerizable compounds are less than 40% by mass, the structural unit of the general formula (A) in the cured composition becomes dilute and the charge transportability is insufficient. Since this polymerizable compound can exhibit good wear resistance even when cured alone, it is preferably used at a concentration as high as possible when intended to improve charge transportability.

<Regarding Additives Having Other Radical Polymerizable Functional Groups>
The crosslinked surface layer of the present invention is formed by applying a coating liquid containing a polymerizable monomer represented by the general formula (A) and then curing the coating liquid. One or more functional radical polymerizable monomers, functional monomers, and radical polymerizable oligomers can be used in combination for the purpose of adjustment, stress relaxation of the crosslinked surface layer, low surface energy reduction, friction coefficient reduction, and the like. Known radical polymerizable monomers and oligomers can be used.

  Examples of the monofunctional radically polymerizable monomer include 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, 2-ethylhexyl carbitol acrylate, 3-methoxybutyl acrylate, benzyl acrylate, Examples include cyclohexyl acrylate, isoamyl acrylate, isobutyl acrylate, methoxytriethylene glycol acrylate, phenoxytetraethylene glycol acrylate, cetyl acrylate, isostearyl acrylate, stearyl acrylate, and styrene monomer.

  Examples of the bifunctional radical polymerizable monomer include 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1, Examples include 6-hexanediol dimethacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, bisphenol A-EO modified diacrylate, bisphenol F-EO modified diacrylate, neopentyl glycol diacrylate, and the like.

  Examples of the functional monomer include those substituted with a fluorine atom such as octafluoropentyl acrylate, 2-perfluorooctylethyl acrylate, 2-perfluorooctylethyl methacrylate, 2-perfluoroisononylethyl acrylate, No. 60503, JP-B-6-45770, siloxane repeating units: 20-70 acryloyl polydimethylsiloxane ethyl, methacryloyl polydimethylsiloxane ethyl, acryloyl polydimethylsiloxane propyl, acryloyl polydimethylsiloxane butyl, diacryloyl polydimethylsiloxane Examples include vinyl monomers having a polysiloxane group such as diethyl, acrylates and methacrylates.

Examples of the radical polymerizable oligomer include epoxy acrylate, urethane acrylate, and polyester acrylate oligomers.
However, when a large amount of monofunctional and bifunctional radically polymerizable monomers and radically polymerizable oligomers are contained, the three-dimensional cross-linking density of the cross-linked surface layer is substantially reduced, resulting in a decrease in wear resistance. For this reason, the content of these monomers and oligomers is limited to 30% by mass or less, preferably 20% by mass or less, based on the total amount of the curable constituent material of the crosslinked surface layer.
Examples of the tri- or higher functional radical polymerizable monomer include the following, but are not limited to these compounds.

  For example, trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate, trimethylolpropane alkylene modified triacrylate, trimethylolpropane ethyleneoxy modified (hereinafter EO modified) triacrylate, trimethylolpropane propyleneoxy modified (hereinafter PO modified) Triacrylate, trimethylolpropane caprolactone modified triacrylate, trimethylolpropane alkylene modified trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol triacrylate, glycerol epichlorohydrin modified (hereinafter ECH modified) triacrylate, Glycerol EO-modified triacrylate, glycerol P Modified triacrylate, tris (acryloxyethyl) isocyanurate, dipentaerythritol hexaacrylate (DPHA), dipentaerythritol caprolactone modified hexaacrylate, dipentaerythritol hydroxypentaacrylate, alkylated dipentaerythritol pentaacrylate, alkylated dipentaerythritol Tetraacrylate, alkylated dipentaerythritol triacrylate, dimethylolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, phosphoric acid EO-modified triacrylate, 2,2,5,5-tetrahydroxymethylcyclopentanone tetraacrylate, etc. These may be used alone or in combination of two or more. There.

  The amount of the monomer having three or more radically polymerizable functional groups that can be mixed and used in the present invention is 0 to 90% by mass, preferably 0 to 50% by mass, based on the total amount of the curable constituent material. In order to fully exhibit the above, it is preferable to make it equal to or less than the radically polymerizable compound of the general formula (A).

<Regarding the polymerization initiator>
The crosslinked surface layer of the present invention is formed by applying a coating liquid containing a polymerizable monomer represented by the above general formula (A) and then curing it. In this case, a curing reaction is performed as necessary. In order to make the process proceed efficiently, a polymerization initiator may be contained in the crosslinked surface layer coating solution.

  Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2- Acetophenone-based or ketal-based photopolymerization initiators such as methyl-2-morpholino (4-methylthiophenyl) propan-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, Benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether Benzoin ether photopolymerization initiators such as benzoin isopropyl ether, benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoylphenyl ether, acrylated benzophenone, Benzophenone photopolymerization initiators such as 1,4-benzoylbenzene, thioxanthones such as 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone Examples of photopolymerization initiators and other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoic acid. Phenylethoxyphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10 -Phenanthrene, an acridine type compound, a triazine type compound, an imidazole type compound is mentioned. Moreover, what has a photopolymerization acceleration effect can also be used individually or in combination with the said photoinitiator. Examples include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, 4,4'-dimethylaminobenzophenone, and the like.

  Examples of the thermal polymerization initiator include 2,5-dimethylhexane-2,5-dihydroperoxide, dicumyl peroxide, benzoyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di ( Peroxybenzoyl) hexyne-3, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, lauroyl peroxide, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) B) Peroxide-based initiators such as propane, azo-based compounds such as azobisisobutylnitrile, azobiscyclohexanecarbonitrile, methyl azobisisobutyrate, azobisisobutylamidine hydrochloride, 4,4′-azobis-4-cyanovaleric acid Initiators are mentioned.

  These polymerization initiators may be used alone or in combination of two or more. Content of a polymerization initiator is 0.5-40 mass parts with respect to 100 mass parts of total inclusions which have radical polymerizability, Preferably it is 1-20 mass parts.

<Other additives>
Furthermore, the cross-linked surface layer coating liquid of the present invention can be applied to various plasticizers (for the purpose of stress relaxation and adhesion improvement), leveling agents, low molecular charge transport materials having no radical reactivity, binder resins, etc. Additives can be included. As these additives, known additives can be used, and as plasticizers, those used in general resins such as dibutyl phthalate and dioctyl phthalate can be used, and the amount used is the total solid content of the coating liquid. To 20% by mass or less, preferably 10% by mass or less. As leveling agents, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain can be used, and the amount used is based on the total solid content of the coating liquid. On the other hand, 3% by mass or less is appropriate. Although the low molecular charge transport material is effective for improving the charge transport property of the crosslinked surface layer and lowering the exposed portion potential, the effect of high wear resistance is reduced because the addition of the curable material decreases. For this reason, the addition amount is adjusted by the process to be used, but it is used at 50% by mass or less, preferably 30% by mass or less, based on the total components of the crosslinked surface layer. The binder resin has the effect of reducing the internal stress of the crosslinked surface layer and increasing the uniformity, and suppressing the occurrence of cracks and scratches. However, since the effect of high wear resistance is reduced by addition as in the case of other additives, the addition amount is suppressed to 20% by mass or less, preferably 10% by mass or less.

<Regarding coating solvent>
When the radically polymerizable compound is a liquid, the coating liquid used for forming the crosslinked surface layer of the present invention can be dissolved and coated with other components, but diluted with a solvent as necessary. Applied. Solvents used at this time include alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, tetrahydrofuran, dioxane and propyl ether. And ethers such as dichloromethane, dichloroethane, trichloroethane and chlorobenzene, aromatics such as benzene, toluene and xylene, cellosolves such as methyl cellosolve, ethyl cellosolve and cellosolve acetate. These solvents may be used alone or in combination of two or more. The dilution ratio with the solvent varies depending on the solubility of the composition, the coating method, and the target film thickness, and is arbitrary. The application can be performed by dip coating, spray coating, bead coating, ring coating, or the like.

In the present invention, after applying such a cross-linked surface layer coating solution, energy is applied from the outside and cured to form a cross-linked surface layer. The external energy used at this time is light, heat, or radiation. is there. As the energy of light, UV irradiation light sources such as high-pressure mercury lamps and metal halide lamps, which mainly have an emission wavelength in ultraviolet light, can be used, but a visible light source can also be selected according to the absorption wavelength of radically polymerizable substances and photopolymerization initiators. Is possible. Irradiation light amount is 50 mW / cm ² or more, preferably 1000 mW / cm ² or less, it takes time for the curing reaction is less than 50 mW / cm ^2. If it is higher than 1000 mW / cm ^2, the progress of the reaction becomes non-uniform, and local flaws are generated on the surface of the crosslinked surface layer, and many unreacted residues and reaction termination ends are generated. In addition, internal stress increases due to rapid crosslinking, which causes cracks and film peeling. The irradiation time depends on the UV light penetrability depending on the constituent material and the film thickness, but is preferably 5 seconds to 5 minutes. If it is too short, curing will be insufficient, and if it is too long, the constituent material will be decomposed and the electrical properties will deteriorate. It is also desirable to control the temperature rise during curing to 120 ° C. or lower to suppress decomposition of the constituent materials and non-uniform curing reaction.

When curing using thermal energy, 10 minutes to 3 hours are preferable at 100 to 170 ° C., and curing is insufficient at a temperature lower than 100 ° C. or a time shorter than 10 minutes. On the other hand, when the temperature is higher than 170 ° C. or longer than 3 hours, decomposition of the constituent materials and uneven curing reaction proceed, and a good crosslinked surface layer cannot be obtained.
An electron beam is preferably used as the energy of radiation. The acceleration voltage of the electron beam is 300 KV or less, preferably 150 KV or less, and the dose is cured under the conditions of 1 to 100 Mrad. When the acceleration voltage exceeds 300 KV or the dose exceeds 100 Mrad, the decomposition of the constituent materials proceeds, and the effect of the present invention is not exhibited.
Among these energies, those using light energy are useful because of the ease of reaction rate control and the simplicity of the apparatus.
Since the thickness of the crosslinked surface layer of the present invention varies depending on the structure of the underlying non-radical-cured photosensitive layer, it will be described later in accordance with the structure of the photosensitive layer.

Hereinafter, the present invention will be described according to the layer structure.
<About the layer structure of the electrophotographic photoreceptor>
The electrophotographic photosensitive member used in the present invention will be described with reference to the drawings.
1 and 2 are sectional views showing the electrophotographic photosensitive member of the present invention.
FIG. 1-A shows a case where a photosensitive layer having a charge generation function and a charge transport function at the same time is provided on a conductive support, and the crosslinked surface layer is the surface portion of the photosensitive layer. That is, the photosensitive layer which is not radically cured represents a photosensitive layer having the charge generating function and the charge transporting function shown in the figure at the same time, and the crosslinked surface layer containing the radical curable composition represents the crosslinked surface layer shown in the figure.
FIG. 1-B shows a single layer structure in which a charge generation layer having a charge generation function is provided as a photosensitive layer on a conductive support, and a crosslinked surface layer having a charge transporting compound is the surface portion of the photosensitive layer. Show the case. That is, the photosensitive layer that is not radically cured represents the charge generation layer in the figure, and the crosslinked surface layer containing the radical curable composition represents the crosslinked surface layer in the figure.
FIG. 2 shows a photoreceptor having a laminated structure in which a charge generation layer having a charge generation function and a charge transport layer having a charge transport function are laminated as a photosensitive layer on a conductive support. The case where the cross-linked surface layer is the surface portion of the charge transport layer is shown. That is, the photosensitive layer that is not radically cured represents the charge generation layer and the charge transport layer in the figure, and the crosslinked surface layer containing the radical curable composition represents the crosslinked surface layer in the figure.

<About conductive support>
Examples of the conductive support include those having a volume resistance of 10 ¹⁰ Ω · cm or less, such as metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, and platinum, tin oxide, and indium oxide. After metal oxide is deposited or sputtered, film or cylindrical plastic, paper coated, or aluminum, aluminum alloy, nickel, stainless steel, etc. Pipes that have been subjected to surface treatment such as cutting, super-finishing, and polishing can be used. Further, endless nickel belts and endless stainless steel belts disclosed in JP-A-52-36016 can also be used as the conductive support.

In addition, those obtained by dispersing and coating conductive powder in an appropriate binder resin on the support can also be used as the conductive support of the present invention.
Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc and silver, or metal oxide powder such as conductive tin oxide and ITO. Can be mentioned. The binder resin used at the same time is 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, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, Examples thereof include thermoplastic, thermosetting resins, and photocurable resins such as melamine resin, urethane resin, phenol resin, and alkyd resin. Such a conductive layer can be provided by dispersing and coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.

  Furthermore, it is electrically conductive by a heat shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, Teflon (registered trademark) on a suitable cylindrical substrate. Those provided with a conductive layer can also be used favorably as the conductive support of the present invention.

<About 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 generation layer having a charge generation function and a charge transport layer having a charge transport function. In the case of a single layer structure, the photosensitive layer is composed of a layer having a charge generation function and a charge transport function at the same time, or a layer having a charge generation function.
Hereinafter, each of the photosensitive layer having a laminated structure and the photosensitive layer having a single layer structure will be described.

<Photosensitive layer having a laminated structure>
(1) Charge generation layer The charge generation layer is a layer mainly composed of a charge generation material having a charge generation function, and a binder resin can be used in combination as necessary. As the charge generation material, inorganic materials and organic materials can be used.
Inorganic materials include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compounds, and amorphous silicon. In amorphous silicon, dangling bonds that are terminated with hydrogen atoms or halogen atoms, or those that are doped with boron atoms, phosphorus atoms, or the like 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, azulenium salt pigments, squaric acid methine pigments, azo pigments having carbazole skeleton, azo pigments having triphenylamine skeleton, azo pigments having diphenylamine skeleton, dibenzothiophene skeleton Azo pigments having a fluorenone skeleton, azo pigments having an oxadiazole skeleton, azo pigments having a bis-stilbene skeleton, azo pigments having a distyryl oxadiazole skeleton, azo pigments having a distyrylcarbazole skeleton, perylene Pigments, anthraquinone or polycyclic quinone pigments, quinoneimine pigments, diphenylmethane and triphenylmethane pigments, benzoquinone and naphthoquinone pigments, cyanine and azomethine pigments, Goido based pigments, and bisbenzimidazole pigments. These charge generation materials can be used alone or as a mixture of two or more.

  As a binder resin used as necessary for the charge generation layer, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, Examples include polyacrylamide. These binder resins can be used alone or as a mixture of two or more. In addition to the binder resin described above as a binder resin for the charge generation layer, a polymer charge transport material having a charge transport function, such as an arylamine skeleton, benzidine skeleton, hydrazone skeleton, carbazole skeleton, stilbene skeleton, pyrazoline skeleton, etc. Polymer materials such as polycarbonate, polyester, polyurethane, polyether, polysiloxane, and acrylic resin, polymer materials having a polysilane skeleton, and the like can be used.

Specific examples of the former include JP-A-01-001728, JP-A-01-009964, JP-A-01-013061, JP-A-01-019049, JP-A-01-241559, Japanese Unexamined Patent Publication Nos. 04-011627, 04-175337, 04-183719, 04-2225014, 04-230767, 04-320420, 05 -232727, JP-A 05-310904, JP-A 06-234836, JP-A 06-234837, JP-A 06-234838, JP-A 06-234839, JP-A 06-234840. No. 1, JP-A-06-234841, JP-A-06-239049, Japanese Unexamined Patent Publication Nos. 06-236050, 06-236051, 06-295077, 07-0756374, 08-176293, 08-208820, 08 No. -21640, JP 08-253568, JP 08-269183, JP 09-062019, JP 09-043883, JP 09-71642, JP 09-87376. No. 1, JP-A 09-104746, JP 09-110974, JP 09-110976, JP 09-157378, JP 09-221544, JP 09-227669. JP 09-235367 A, JP 09-241369 A Charge transporting polymer materials described in JP 09-268226 A, JP 09-272735 A, JP 09-302084 A, JP 09-302085 A, JP 09-328539 A, etc. Can be mentioned.
Specific examples of the latter include polysilylene polymers described in, for example, JP-A 63-285552, JP-A 05-19497, JP-A 05-70595, JP-A 10-73944, and the like. Illustrated.

The charge generation layer may contain a low molecular charge transport material.
Low molecular charge transport materials that can be used in the charge generation layer include hole transport materials and electron transport materials.
Examples of the electron transporting material include chloroanil, 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-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide and diphenoquinone derivatives. These electron transport materials can be used alone or as a mixture of two or more.

  Examples of the hole transporting material include the electron donating materials shown below and are used favorably. As hole transport materials, 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 methane derivatives, 9-styrylanthracene derivatives, pyrazoline derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, bisstilbene derivatives, enamine derivatives, and the like can be given. These hole transport materials can be used alone or as a mixture of two or more.

Methods for forming the charge generation layer include a vacuum thin film preparation method and a casting method from a solution dispersion system.
As the former method, a vacuum 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-described inorganic materials and organic materials can be satisfactorily formed.
In addition, in order to provide a charge generation layer by the casting method described later, if necessary, the inorganic or organic charge generation material together with a binder resin, tetrahydrofuran, dioxane, dioxolane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, cyclohexane. Can be formed by dispersing with a ball mill, attritor, sand mill, bead mill, etc. using a solvent such as pentanone, anisole, xylene, methyl ethyl ketone, acetone, ethyl acetate, butyl acetate, etc. . Moreover, leveling agents, such as a dimethyl silicone oil and a methylphenyl silicone oil, can be added as needed. The application can be performed by dip coating, spray coating, bead coating, ring coating, 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.

(2) Charge Transport Layer The charge transport layer is formed by dissolving or dispersing a charge transport material having a charge transport function and a binder resin in a suitable solvent, and applying and drying the solution on the charge generation layer.
As the charge transport material, the electron transport material, hole transport material and polymer charge transport material described in the charge generation layer can be used. In particular, the use of a polymer charge transport material is particularly useful because it has an effect of reducing the solubility of the lower layer during coating of the crosslinked surface layer.

Examples of the binder resin include 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, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin And thermoplastic or thermosetting resins such as phenol resins and alkyd resins.
The amount of the charge transport material is appropriately 20 to 300 parts by mass, preferably 40 to 150 parts by mass with respect to 100 parts by mass of the binder resin. However, when a 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, the same solvent as that used for the charge generation layer can be used, but a solvent that dissolves the charge transport material and the binder resin well is suitable. These solvents may be used alone or in combination of two or more. The charge transport layer can be formed by the same coating method as that for the charge generation layer.

If necessary, a plasticizer and a leveling agent can be added.
As a plasticizer that can be used in combination with the charge transport layer, those used as a plasticizer for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is 0 with respect to 100 parts by mass of the binder resin. About 30 parts by mass is appropriate.
Leveling agents that can be used in combination with the charge transport layer include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain. The amount used is a binder resin. About 0 to 1 part by mass is appropriate for 100 parts by mass.
The thickness of the charge transport layer is suitably about 5 to 40 μm, preferably about 10 to 30 μm.

  As described above in the method for preparing a crosslinked surface layer, the crosslinked surface layer is coated with the crosslinked surface layer coating solution of the present invention on such a charge transport layer, dried as necessary, and then subjected to light, heat or radiation. The curing reaction is initiated by energy, and a crosslinked surface layer is formed. In the case where the photosensitive layer is a laminated structure, the crosslinked surface layer contains a charge transporting compound (regardless of having or not having a radical polymerizable functional group) and imparting a charge transporting function, It is good also as a protective layer, without containing. At this time, the film thickness of the cross-linked surface layer is 1 μm or more and 15 μm or less, more preferably 2 μm or more and 13 μm or less when the charge transport function is imparted. When it is thicker than 15 μm, cracks and film peeling tend to occur. When it is used as a protective layer without imparting a charge transport function, the crosslink density can be further increased, and the wear resistance can be enhanced. In this case, the thickness of the crosslinked surface layer is 1 μm or more and 5 μm or less, more preferably 2 μm or more and 4 μm or less. When it is thicker than 5 μm, cracks and film peeling tend to occur as described above. Moreover, since there is no charge transport capability, a significant reduction in sensitivity occurs. When the film thickness of the cross-linked surface layer is less than 1 μm, durability varies due to film thickness unevenness.

<Single photosensitive layer>
The photosensitive layer having a single layer structure is a layer having a charge generation function and a charge transport function at the same time, or a charge generation layer having a charge generation function.
(1) In the case of a single layer structure having both a charge generation function and a charge transport function When the photosensitive layer is a layer having both a charge generation function and a charge transport function, the photosensitive layer has a charge generation function and a charge transport function. It can be formed by dissolving or dispersing a charge transport material having a function and a binder resin in an appropriate solvent, and applying and drying the solution. Moreover, a plasticizer, a leveling agent, etc. can also be added as needed. As the charge generation material dispersion method, the charge generation material, the charge transport material, the plasticizer, and the leveling agent may be the same as those already described in the charge generation layer and the charge transport layer. As the binder resin, in addition to the binder resin previously mentioned in the section of the charge transport layer, the binder resin mentioned in the charge generation layer may be mixed and used. In addition, the polymer charge transport materials listed above can also be used, which is useful in that the mixing of the photosensitive layer composition into the crosslinked surface layer can be reduced. The charge generation material contained in the photosensitive layer is preferably 1 to 30% by mass relative to the total amount of the photosensitive layer, the binder resin contained in the photosensitive layer is 20 to 80% by mass, and the charge transport material is 10 to 70% by mass. Part is used well.
The film thickness of the photosensitive layer is suitably about 5 to 30 μm, preferably about 10 to 25 μm.

  When the cross-linked surface layer is a surface portion of a photosensitive layer having a single layer structure, the cross-linked surface layer coating solution of the present invention is applied onto the photosensitive layer as described above, and after drying, if necessary, light, heat or radiation It cures by the energy of and forms a crosslinked surface layer. When the photosensitive layer has the single layer structure, the crosslinked surface layer contains a charge transporting compound (regardless of having or not having a radical polymerizable functional group) and imparting a charge transporting function. However, it is good also as a protective layer, without containing. At this time, the film thickness of the cross-linked surface layer is 1 μm or more and 15 μm or less, more preferably 2 μm or more and 13 μm or less when the charge transport function is imparted. When it is thicker than 15 μm, cracks and film peeling tend to occur. When it is used as a protective layer without imparting a charge transport function, the crosslinking density can be further increased and the wear resistance can be enhanced. In this case, the thickness of the crosslinked surface layer is 1 μm or more and 5 μm or less, more preferably 2 μm or more and 4 μm or less. When it is thicker than 5 μm, cracks and film peeling tend to occur as described above. Moreover, since there is no charge transport capability, a significant reduction in sensitivity occurs. When the film thickness of the cross-linked surface layer is less than 1 μm, durability varies due to film thickness unevenness.

(2) In the case of a single-layer structure of a charge generation layer having a charge generation function When the photosensitive layer is a charge generation layer having a charge generation function, the charge generation layer has the same structure as the charge generation layer raised in the laminated structure. Things can be used. The cross-linked surface layer provided on the charge generation layer contains a charge transporting compound in order to have a charge transporting function. At this time, the charge transporting compound may or may not have a radical polymerizable functional group. However, when a compound having a radical polymerizable functional group is used as the charge transporting compound, the high wear resistance effect of the present invention can be exhibited more excellently, which is preferable. The cross-linked surface layer having a charge transport function is applied with the cross-linked surface layer coating solution of the present invention on the charge generation layer as described in the above-mentioned cross-linked surface layer preparation method, and if necessary, dried, light, heat or The curing reaction is initiated by the energy of the radiation, and a crosslinked surface layer is formed. At this time, the film thickness of the crosslinked surface layer is 10 to 30 μm, preferably 10 to 25 μm. If it is thinner than 10 μm, a sufficient charging potential cannot be maintained, and if it is thicker than 30 μm, peeling from the lower layer tends to occur due to volume shrinkage during curing.

<About the intermediate layer>
In the photoreceptor of the present invention, when the crosslinked surface layer becomes the surface portion of the photosensitive layer, an intermediate layer can be provided between the crosslinked surface layer and the photosensitive layer. This intermediate layer prevents inhibition of the curing reaction and unevenness of the crosslinked surface layer caused by mixing of the photosensitive layer composition that is not radically cured in the crosslinked surface layer containing the radical curable composition. It is also possible to improve the adhesion between the underlying photosensitive layer and the crosslinked surface layer.

  In the intermediate layer, a binder resin is generally used as a main component. Examples of these resins include polyamide, alcohol-soluble nylon, water-soluble polyvinyl butyral, polyvinyl butyral, and polyvinyl alcohol. As a method for forming the intermediate layer, a generally used coating method is employed as described above. In addition, about 0.05-2 micrometers is suitable for the thickness of an intermediate | middle layer.

<About the undercoat layer>
In the photoreceptor of the present invention, an undercoat layer can be provided between the conductive support and the photosensitive layer. In general, the undercoat layer is mainly composed of a resin. However, considering that the photosensitive layer is coated with a solvent on these resins, the resin may be a resin having high solvent resistance with respect to a general organic solvent. desirable. Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. Further, a metal oxide fine powder pigment exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like may be added to the undercoat layer in order to prevent moire and reduce residual potential.

These undercoat layers can be formed using an appropriate solvent and a coating method like the above-mentioned photosensitive layer. Furthermore, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the undercoat layer of the present invention. In addition, in the undercoat layer of the present invention, Al ₂ O ₃ is provided by anodic oxidation, organic matter such as polyparaxylylene (parylene), SiO ₂ , SnO ₂ , TiO ₂ , ITO, CeO ₂ A material provided with an inorganic material such as a vacuum thin film can also be used favorably. In addition, known ones can be used. The thickness of the undercoat layer is suitably from 0 to 5 μm.

<Addition of antioxidant to each layer>
Further, in the present invention, in order to improve environmental resistance, in order to prevent a decrease in sensitivity and an increase in residual potential, in particular, a crosslinked surface layer, a charge generation layer, a charge transport layer, an undercoat layer, an intermediate layer, etc. Antioxidants can be added to each layer.

The following are mentioned as antioxidant which can be used for this 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-tert-butylphenol), 2,2'-methylene-bis- (4-ethyl-6-tert-butylphenol), 4, 4'-thiobis- (3-methyl-6-tert-butylphenol), 4,4'-butylidenebis- (3-methyl-6-tert-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 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, bis [3,3'-bis (4'-hydroxy-3'-t-butylphenyl) butyric acid ] Cryol ester, tocopherols and the like.

(Paraphenylenediamines)
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, dimyristyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate, penta Erythritol tetrakis (3-laurylthio-propionate) and the like.

(Organic phosphorus compounds)
Triphenyl phosphite, tris (nonylphenyl) phosphite, tri (dinonylphenyl) phosphite, tris (2-ethylhexyl) phosphite, tridecyl phosphite, tris (tridecyl) phosphite, diphenyl mono (2-ethylhexyl) Phosphite, diphenyl monodecyl phosphite, tris (2,4, di-t-butylphenyl) phosphite, distearyl pentaerythritol diphosphite, bis (2,4, di-t-butylphenyl) pentaerythritol phosphite, 2 , 2-methylenebis (4,6-di-t-butylphenyl) octyl phosphite, tetrakis (2,4-di-t-butylphenyl) 4,4′-biphenylene-diphosphonite, dilauryl hydrogen phosphite, diphenyl Hydrogen phosphite, tetraphenyldipropylene glycol diphosphite, tetraphenyltetra (tridecyl) pentaerythritol tetraphosphite, tetra (tridecyl) -4,4′isopropylidene diphenyldiphosphite, bis (nonylphenyl) pentaerythritol diphos Phyto, hydrogenated bisphenol A, pentaerythritol phosphite polymer, etc.
These compounds are known as antioxidants such as rubbers, plastics and fats and oils, and commercially available products can be easily obtained.

<Image Forming Method and 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 use a photoconductor having a non-radical-cured photosensitive layer of the present invention and a crosslinked surface layer containing a specific radical-curing composition. An image forming method and an image forming apparatus comprising processes of image exposure and development, followed by a process of transferring a toner image onto an image carrier (transfer paper), fixing, and cleaning of the surface of the photoreceptor.
In some cases, an image forming method or the like in which an electrostatic latent image is directly transferred to a transfer member and developed does not necessarily have the above-described process arranged on the photosensitive member.

  FIG. 3 is a schematic diagram illustrating an example of an image forming apparatus. A charging charger (3) is used as a means for charging the photoconductor on average. As the charging means, a corotron device, a scorotron device, a solid discharge element, a needle electrode device, a roller charging device, a conductive brush device, or the like is used, and a known system can be used.

  Next, the image exposure unit (5) is used to form an electrostatic latent image on the uniformly charged photoreceptor (1). As the light source, all luminescent materials such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL) can be used. Various types of filters such as a sharp cut filter, a band pass 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 (1). Development methods include a one-component development method using a dry toner, a two-component development method, and a wet development method using a wet toner. When the photosensitive member is positively (negatively) charged and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. A positive image can be obtained by developing this with negative (positive) toner (electrodetection fine particles), and a negative image can be obtained by developing with positive (negative) toner.

  Next, a transfer charger (10) is used to transfer the toner image visualized on the photoconductor onto the transfer body (9). In addition, a pre-transfer charger (7) may be used for better transfer. As these transfer means, a transfer charger, an electrostatic transfer method using a bias roller, a mechanical transfer method such as an adhesive transfer method and a pressure transfer method, and 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 body (9) from the photoreceptor (1). As other separation means, electrostatic adsorption induction separation, side end belt separation, tip grip conveyance, curvature separation, and the like are used. As the separation charger (11), the charging means can be used.

Next, a fur brush (14) and a cleaning blade (15) are used to clean the toner remaining on the photoreceptor after transfer. Further, a pre-cleaning charger (13) may be used in order to perform cleaning more efficiently. As other cleaning means, there are a web system, a magnet brush system, and the like, but a single system or a plurality of systems may be used together.
Next, a neutralizing unit is used for the purpose of removing the latent image on the photoconductor as necessary. As the charge removal means, a charge removal lamp (2) and a charge removal charger are used, and the exposure light source and the charging means can be used respectively.
In addition, known processes can be used for reading, feeding, fixing, paper discharge and the like that are not close to the photoconductor.

The present invention is an image forming method and an image forming apparatus using the electrophotographic photoreceptor according to the present invention for such image forming means.
This image forming means may be fixedly incorporated in a copying apparatus, facsimile, or printer, but may be incorporated in these apparatuses in the form of a process cartridge and detachable. An example of the process cartridge is shown in FIG.
The process cartridge for the image forming apparatus includes a photoconductor (101), in addition to a charging unit (102), an exposure unit (103), a developing unit (104), a transfer unit (106), a cleaning unit (107), This is an apparatus (part) that includes at least one static elimination unit (not shown) and is detachable from the image forming apparatus main body.
The image forming process by the apparatus illustrated in FIG. 4 will be described. The photosensitive member (101) corresponds to an exposure image on the surface thereof by rotating by the charging means (102) and exposure by the exposure means (103) while rotating. The electrostatic latent image is formed, and the electrostatic latent image is developed with toner by the developing means (104). The toner development is transferred to the transfer body (105) by the transfer means (106) and printed out. . Next, the surface of the photoconductor after the image transfer is cleaned by a cleaning unit (107), and is further neutralized by a neutralizing unit (not shown), and the above operation is repeated again.

The present invention integrates at least one of charging, developing, transferring, cleaning, and neutralizing means with the photosensitive member according to the present invention having a photosensitive layer that is not radically cured and a crosslinked surface layer containing a specific radical curing composition. A process cartridge for an image forming apparatus is provided.
As is apparent from the above description, the electrophotographic photosensitive member of the present invention is not only used in electrophotographic copying machines, but also in electrophotographic application fields such as laser beam printers, CRT printers, LED printers, liquid crystal printers, and laser plate making. Can also be used widely.

<Synthesis of Radical Reactive Compound Represented by Formula (A) Used in the Present Invention>
(1) Synthesis example of A1-1 A synthesis method of 2,3-dihydroxypropyloxylation of a diphenol derivative will be described.
The diphenol derivative used as a raw material is synthesized by a conventionally known method. For example, it can be synthesized by the method described in JP-A-9-278723. In this publication, Exemplified Compound Nos. Described in [Table 1] are listed. 22 or No. 23, including a method for synthesizing diphenol derivatives in which two phenyl groups substituted on the N atom are different from each other.
The 2,3-dihydroxypropyloxylation of the phenolic OH group is produced by ring-opening addition reaction of a carboxylic acid glycidyl ester compound such as glycidyl methacrylate with a diphenol derivative as described in the following reaction formula (1). The desired tetrahydroxy compound can be easily synthesized in high yield by hydrolyzing the hydroxy group-containing dicarboxylic acid diester intermediate.
Glycidyl methacrylate is a reagent available as an industrial reagent and is one of the preferred carboxylic acid glycidyl ester compounds.
The reaction can be carried out by dissolving the diol compound and glycidyl methacrylate in a suitable solvent and stirring with heating. At that time, it is effective to add a small amount of a tertiary amine compound or a quaternary ammonium salt compound as a catalyst.
As the solvent, aromatic hydrocarbon solvents such as toluene, ester solvents such as ethyl acetate, and ether solvents such as tetrahydrofuran can be used.
Heating is from room temperature to 150 ° C, preferably from 60 ° C to 120 ° C.
If the temperature is too low, the reaction time will be slow, and if it is too high, side reactions will increase.
Specific examples of the tertiary amine used as the catalyst include triethylamine and benzyldiethylamine. Specific examples of the quaternary ammonium salt include benzylethylammonium chloride and tetraethylammonium chloride.
The amount of the catalyst added is about 0.01 to 5 wt% of the diol compound, and usually about 1 to 2 wt% is sufficient.
The reaction time is from several hours to several tens of hours, and the reaction is completed in 5 to 10 hours in the preferred temperature range and catalyst addition amount.
In order to rapidly hydrolyze the hydroxy group-containing dicarboxylic acid diester intermediate obtained at this time, an aqueous solution of an inorganic base such as sodium hydroxide may be added and further heated and stirred. The reaction temperature at this time may be room temperature to 100 ° C, preferably 60 ° C to 95 ° C. Hydrolysis is usually complete in a few hours.

また、下記反応式（２）に記載の様にジフェノール誘導体にエピクロロヒドリンを反応させ、得られるエポキシ化合物に水を開環付加させて目的物を得ることもできる。

Further, as described in the following reaction formula (2), epichlorohydrin can be reacted with a diphenol derivative, and water can be subjected to ring-opening addition to the resulting epoxy compound to obtain the desired product.

  As specific examples, Exemplified Compound Nos. Synthesis of N- {4- [2,2-bis (4- (2,3-dihydroxypropyloxy) phenyl) vinyl] phenyl} -N, N-bis (4-tolyl) amine as a precursor of 2 Present about.

<Synthesis of N- {4- [2,2-bis (4- (2,3-dihydroxypropyloxy) phenyl) vinyl] phenyl} -N, N-bis (4-tolyl) amine>
A reaction vessel containing 14.51 g of N- {4- [2,2-bis (4-hydroxyphenyl) vinyl] phenyl} -N, N-bis (4-tolyl) amine, 9.45 g of glycidyl methacrylate, and 20 ml of toluene. The mixture was heated to 90 ° C. with stirring, 0.24 g of triethylamine was added, and the mixture was reacted at 95 ° C. for 7.5 hours.
Thereafter, the mixture was once cooled, 30 ml of a 10% aqueous sodium hydroxide solution and 15 ml of toluene were added, the temperature was raised again, and the mixture was reacted at 90 ° C. for 3 hours.
After allowing to cool, 60 ml of water and 100 ml of 0.5N hydrochloric acid aqueous solution were added, and the product was extracted with ethyl acetate. The obtained organic layer was washed with a dilute hydrochloric acid aqueous solution and then with a saturated saline solution, and further dehydrated by adding anhydrous magnesium sulfate.
Thereafter, filtration and concentration were performed, and column purification was performed using silica gel with a mixed solvent of ethyl acetate and tetrahydrofuran. As a result, 13.29 g of the desired product was obtained as a yellow amorphous solid. (Yield 70%)

(2) Synthesis example of A1-2 The (meth) acrylation of a tetrahydroxy derivative will be described.
Acrylation and methacrylation can be synthesized by esterification reaction of acrylic acid or methacrylic acid and an alcohol derivative, respectively. Acrylic acid chloride and methacrylic acid chloride may also be used. In the case of acrylation, it can be easily synthesized by esterifying with 3-chloropropanoic acid chloride and an alcohol derivative and then dehydrochlorinating in the presence of a base. Exemplified Compound No. Two synthesis examples are presented.

<Exemplary Compound No. Synthesis of 2>
In a reaction vessel equipped with a stirrer, a thermometer, and a condenser, N- {4- [2,2-bis (4- (2,3-dihydroxypropyloxy) phenyl) vinyl] phenyl} -N, N-bis 3.16 g of (4-tolyl) amine and 30 ml of N, N-dimethylacetamide were added, and 3.81 g of 3-chloropropionyl chloride was slowly added dropwise while cooling with ice. Then, it stirred at room temperature for 5 hours. Next, 6.07 g of triethylamine was added and reacted at 60 ° C. for 5 hours. After cooling, the reaction solution was diluted with 100 ml of dichloromethane and washed twice with water, and then the organic layer was taken out and dehydrated by adding magnesium sulfate. Thereafter, the solvent was removed, and purification was performed by column chromatography (adsorption medium: silica gel, developing solvent: n-hexane / ethyl acetate (5/2)). Thus, Exemplified Compound No. 2 acrylate derivatives were obtained. (Yellow oil, yield 2.99 g) was obtained.

  Similar to the above synthesis examples, other exemplary compounds can be easily synthesized by changing the type of diphenol derivative used in A1-1 and the type of carboxylic acid derivative used in A1-2.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to a following example. Note that “parts” used in the examples all represent parts by mass.
<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 order on a φ30 mm aluminum cylinder in sequence, an undercoat layer of 3.5 μm A 0.2 μm charge generation layer and a 15 μm charge transport layer were formed. On this charge transport layer, a cross-linked surface layer coating solution having the following composition is spray-coated and naturally dried for 20 minutes, and then a metal halide lamp: 160 W / cm, irradiation distance: 120 mm, irradiation intensity: 500 mW / cm ² , irradiation time : Irradiated with light for 120 seconds to cure the coating film. Further, drying was performed at 130 ° C. for 20 minutes to provide a 12 μm cross-linked surface layer to obtain an electrophotographic photoreceptor of the present invention.

[Undercoat layer coating solution]
-Alkyd resin: 6 parts (Beccosol 1307-60-EL, manufactured by Dainippon Ink & Chemicals, Inc.)
Melamine resin: 4 parts (Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals)
・ Titanium oxide: 40 parts ・ Methyl ethyl ketone: 50 parts

[Coating liquid for charge generation layer]
-Bisazo pigment with the following structure: 2.5 parts

・ポリビニルブチラール（ＸＹＨＬ、ＵＣＣ製）： ０．５部
・シクロヘキサノン： ２００部
・メチルエチルケトン： ８０部

Polyvinyl butyral (XYHL, manufactured by UCC): 0.5 part Cyclohexanone: 200 parts Methyl ethyl ketone: 80 parts

[Coating fluid for charge transport layer]
-Bisphenol Z-type polycarbonate: 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
-Charge transport material with the following structural formula: 7 parts

・テトラヒドロフラン： １００部
・１％シリコーンオイルのテトラヒドロフラン溶液： １部
（ＫＦ５０−１００ＣＳ、信越化学工業製）

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

[Crosslinked surface layer coating solution]
-Radical polymerizable compound of the structural formula (Exemplary Compound No. 2): 10 parts-Monomer having 3 or more radical polymerizable functional groups: 10 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku Co., Ltd.)
Tetrahydrofuran: 100 parts

<Example 2>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the crosslinked surface layer coating solution of Example 1 was changed to the following.

[Crosslinked surface layer coating solution]
-Radical polymerizable compound of the structural formula (Exemplary Compound No. 2): 10 parts-Monomer having 3 or more radical polymerizable functional groups: 10 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku Co., Ltd.)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 3>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the crosslinked surface layer coating solution of Example 1 was changed to the following.

[Crosslinked surface layer coating solution]
-Radical reactive compound of the structural formula (Exemplary Compound No. 2): 10 parts-Monomer having 3 or more radical polymerizable functional groups: 10 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku)
Photopolymerization initiator 1: 0.5 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Photopolymerization initiator 2: 0.5 part (Irgacure 819, manufactured by Ciba Specialty Chemicals)
・ 100 parts of tetrahydrofuran

<Example 4>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the crosslinked surface layer coating solution of Example 1 was changed to the following.

[Crosslinked surface layer coating solution]
-Radical polymerizable compound of the above structural formula (Exemplary Compound No. 2): 20 parts-Photopolymerization initiator 1: 0.5 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Photopolymerization initiator 2: 0.5 part (Irgacure 819, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 5>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the crosslinked surface layer coating solution of Example 1 was changed to the following.

[Crosslinked surface layer coating solution]
-Radical reactive compound of the structural formula (Exemplary Compound No. 1): 20 parts-Photopolymerization initiator 1: 0.5 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Photopolymerization initiator 2: 0.5 part (Irgacure 819, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 6>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the crosslinked surface layer coating solution of Example 1 was changed to the following.

[Crosslinked surface layer coating solution]
-Radical reactive compound of the structural formula (Exemplary Compound No. 20): 20 parts-Photopolymerization initiator 1: 0.5 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Photopolymerization initiator 2: 0.5 part (Irgacure 819, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 7>
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 order on a φ100 mm aluminum cylinder in sequence, an undercoat layer of 3.5 μm A 0.2 μm charge generation layer and a 15 μm charge transport layer were formed. The cross-linked surface layer coating solution having the following composition is spray-coated on this charge transport layer, naturally dried for 20 minutes, and then heated and cured at 130 ° C. for 90 minutes to provide a 14 μm cross-linked surface layer. A photoreceptor was obtained.

[Undercoat layer coating solution]
-Alkyd resin: 6 parts (Beccosol 1307-60-EL, manufactured by Dainippon Ink & Chemicals, Inc.)
Melamine resin: 4 parts (Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals)
・ Titanium oxide: 40 parts ・ Methyl ethyl ketone: 50 parts

[Coating liquid for charge generation layer]
Y-type titanyl phthalocyanine: 2.5 parts Polyvinyl butyral (XYHL, manufactured by UCC): 0.5 parts Cyclohexanone: 200 parts Methyl ethyl ketone: 80 parts

[Coating fluid for charge transport layer]
-Bisphenol Z-type polycarbonate: 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
-Charge transport material with the following structural formula: 7 parts

・テトラヒドロフラン： １００部
・１％シリコーンオイルのテトラヒドロフラン溶液： １部
（ＫＦ５０−１００ＣＳ、信越化学工業製）

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

[Crosslinked surface layer coating solution]
-Radical polymerizable compound of the above structural formula (Exemplary Compound No. 11): 20 parts-Polymerization initiator: 1 part Azobisbutyronitrile-Tetrahydrofuran: 100 parts

<Example 8>
An electrophotographic photosensitive member was produced in the same manner as in Example 7, except that the crosslinked surface layer coating solution of Example 7 was changed to the following.

[Crosslinked surface layer coating solution]
-Radical polymerizable compound of the above structural formula (Exemplary Compound No. 12): 20 parts-Polymerization initiator: 1 part Benzoyl peroxide-Tetrahydrofuran: 100 parts

<Example 9>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that a φ100 mm aluminum cylinder was used and the charge generation layer coating solution and the crosslinked surface layer coating solution were changed to the following.

[Coating liquid for charge generation layer]
Y-type titanyl phthalocyanine: 2.5 parts Polyvinyl butyral (XYHL, manufactured by UCC): 0.5 parts Cyclohexanone: 200 parts Methyl ethyl ketone: 80 parts

[Crosslinked surface layer coating solution]
-Radical reactive compound of the above structural formula (Exemplary Compound No. 2): 20 parts-Photopolymerization initiator 1: 0.5 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Photopolymerization initiator 2: 0.5 part (Irgacure 819, manufactured by Ciba Specialty Chemicals)
・ 100 parts of tetrahydrofuran

<Comparative Example 1>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the crosslinked surface layer of Example 1 was not provided and the thickness of the charge transport layer was 27 μm.

<Comparative example 2>
An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the cross-linked surface layer of Example 7 was not provided and the thickness of the charge transport layer was 27 μm.

<Comparative Example 3>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the radical reactive compound used in the crosslinked surface layer coating solution of Example 1 was changed to the following.

<Comparative Example 4>
An electrophotographic photosensitive member was produced in the same manner as in Example 2 except that the radical reactive compound used in the crosslinked surface layer coating solution of Example 2 was changed to the following.

<Comparative Example 5>
An electrophotographic photosensitive member was produced in the same manner as in Example 2 except that the radical reactive compound used in the crosslinked surface layer coating solution of Example 2 was changed to the following.

<Comparative Example 6>
An electrophotographic photosensitive member was produced in the same manner as in Example 2 except that the radical reactive compound used in the crosslinked surface layer coating solution of Example 2 was changed to the following.

<Comparative Example 7>
An electrophotographic photosensitive member was produced in the same manner as in Example 2 except that the radical reactive compound used in the crosslinked surface layer coating solution of Example 2 was changed to the following.

<Comparative Example 8>
An electrophotographic photosensitive member was produced in the same manner as in Example 4 except that the radical reactive compound used in the crosslinked surface layer coating solution of Example 4 was changed to the following.

<Comparative Example 9>
An electrophotographic photosensitive member was produced in the same manner as in Example 4 except that the radical reactive compound used in the crosslinked surface layer coating solution of Example 4 was changed to the following.

<Comparative Example 10>
An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the radical reactive compound used in the crosslinked surface layer coating solution of Example 7 was changed to the following.

<Comparative Example 11>
An electrophotographic photosensitive member was produced in the same manner as in Example 8 except that the radical reactive compound used in the crosslinked surface layer coating solution of Example 8 was changed to the following.

  The electrophotographic photoreceptors of Examples 1 to 6 and Comparative Examples 1 and 3 to 9 prepared as described above were subjected to a paper passing test (normal temperature and normal humidity) of 50,000 A4 sizes. First, the photoconductor was mounted on a process cartridge for an electrophotographic apparatus, and 50,000 sheets were printed on a black station of Ricoh's Ipsio CX9000 using a 655 nm semiconductor laser as an image exposure light source. The amount of wear of the electrophotographic photosensitive member at that time (the value obtained by subtracting the photosensitive member film thickness after printing from the initial photosensitive member film thickness) and the developing portion surface potential at the time of solid writing (the initial value and after copying 50,000 sheets) Value). The results are shown in Table 2 below.

  Further, the electrophotographic photosensitive members of Examples 7 to 9 and Comparative Examples 2 and 10 to 11 prepared as described above were subjected to a paper passing test (normal temperature and normal humidity) of 200,000 sheets of A4 size. A photoconductor was set on a ricohic image Neo Neo 752 using a 780 nm semiconductor laser as an exposure light source, and 200,000 copies were made. The amount of wear of the electrophotographic photosensitive member at that time (a value obtained by subtracting the photosensitive member film thickness after copying from the initial photosensitive member film thickness) and the developing portion surface potential at the time of solid writing (the initial value and after copying 200,000 sheets) Value) was measured with the process control turned off. The results are shown in Table 3 below.

As described above, the examples of the present invention have much higher abrasion resistance than conventional organic photoreceptors without a protective layer. In addition, it has the highest level of wear resistance compared to conventional organic photoconductors having a charge transporting radical curing protective layer, and is excellent in potential attenuation characteristics during exposure, while undergoing various fatigue over time. The potential decay characteristic can be maintained. Moreover, the said characteristic can be expressed despite thick film compared with the conventional protective layer. Because of such characteristics, the electrophotographic photosensitive member of the present invention has a very long life.
Further, when Examples 4 to 6 and Examples 1 to 3 are compared, the surface of the developing portion when solid writing is performed when the compound represented by the general formula (A) is used without mixing with other polymerizable monomers. It can be seen that the potential is low from the beginning, and excellent charge transport properties are exhibited.
Moreover, when Examples 7-8 and Example 9 are compared, it turns out that the direction where it hardens | cures using light energy is more excellent in abrasion resistance compared with the case where a cured film is produced by thermosetting.
Therefore, by using this photoreceptor, it is possible to provide a high-performance and highly reliable image forming process, an image forming apparatus, and a process cartridge for an image forming apparatus that can provide a higher quality image over a long period of time.

FIG. 3 is a diagram illustrating a layer configuration of an electrophotographic photosensitive member of the present invention. It is a figure showing another layer structure of the electrophotographic photosensitive member of this invention. 1 is a schematic diagram illustrating an example of an image forming apparatus of the present invention. It is the schematic which shows an example of the process cartridge of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Static elimination lamp 3 Charger 4 Eraser 5 Image exposure part 6 Developing unit 7 Pre-transfer charger 8 Registration roller 9 Transfer body 10 Transfer charger 11 Separation charger 12 Separation claw 13 Pre-cleaning charger 14 Fur brush 15 Cleaning blade 101 Photoconductor 102 Charging means 103 Exposure means 104 Development means 105 Transfer body 106 Transfer means 107 Cleaning means

Claims (8)

An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive member has a charge transport cross-linked surface layer formed by curing at least a compound represented by the following general formula (A) on the surface. An electrophotographic photoreceptor.

(In the formula, R _{1 to} R ₄ each represent a hydrogen atom or a methyl group, and R _{5 to} R ₁₇ each represent a hydrogen atom and an alkyl group having 1 to 4 carbon atoms.) The crosslinked surface layer is formed by curing a coating layer containing at least a compound represented by the general formula (A) and a monomer having a radical polymerizable functional group. The electrophotographic photosensitive member according to claim 1. 3. The electrophotographic photosensitive member according to claim 1, wherein the crosslinked surface layer is formed on an uncured photosensitive layer. The electrophotographic photosensitive member according to claim 1, wherein the crosslinked surface layer is cured by means using light energy. 5. The electrophotographic photosensitive member according to claim 1, wherein the uncured photosensitive layer has a structure in which at least a charge generation layer and a charge transport layer are sequentially laminated on a conductive support. . An image forming method using an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of claims 1 to 5. 6. The electrophotographic photosensitive member according to claim 1, wherein at least a charging unit, an exposing unit, a developing unit, a transferring unit, and an electrophotographic photosensitive member are provided. An image forming apparatus, comprising: 6. An image is formed by integrating the electrophotographic photosensitive member according to claim 1 and at least one means selected from a charging means, an exposure means, a developing means, a transfer means, a cleaning means, and a static elimination means. A process cartridge which is detachable from the apparatus.

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