JP4771892B2 - Electrophotographic photoreceptor, image forming method using the same, image forming apparatus, process cartridge for image forming apparatus, and method for manufacturing electrophotographic photoreceptor - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member that achieves high reliability by achieving both high wear resistance and stable electrical characteristics over a long period of time and extremely reducing the influence of environmental fluctuations. 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-performance photoconductor.

  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. The reasons for this are, for example, (i) optical characteristics such as the light absorption wavelength range and the amount of absorption, (ii) electrical characteristics such as high sensitivity and stable charging characteristics, and (iii) selection of materials. Examples include a wide range, (iv) ease of production, (v) low cost, (vi) nontoxicity, 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 surface layer is mainly composed of low-molecular charge transport materials and inert polymers, and when used repeatedly in electrophotographic processes, they are mechanically driven by development systems and cleaning systems. There is a drawback that wear is likely to occur due to a typical 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 the 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. Under the present circumstances, the wear and scratches are rate-determined and the life of the photoconductor has been replaced.

  Therefore, it is indispensable to reduce the above-mentioned wear amount in order to increase the durability of the organic photoreceptor, and to provide excellent cleaning properties and transfer properties, it has good surface properties, and further has electrophotographic characteristics. There is a need for an organic photoreceptor that does not depend on the location for a long period of time and maintains stable high performance, and these are the most pressing issues in the field.

  Techniques for improving the abrasion resistance of the photosensitive layer include (1) using a curable binder for the surface layer (Patent Document 1: Japanese Patent Laid-Open No. 56-48637), (2) polymer type charge transport material (Patent Document 2: Japanese Patent Laid-Open No. 64-1728), (3) those obtained by dispersing an inorganic filler in the surface layer (Patent Document 3: Japanese Patent Laid-Open No. 4-281461), and the like. Among these techniques, those using the curable binder (1) have poor compatibility with the charge transport material, and the residual potential increases due to impurities such as polymerization initiators and unreacted residues, resulting in a decrease in image density. Tends to occur. In addition, (2) using a polymer type charge transport material and (3) dispersed inorganic filler are required for organic photoreceptors, although they can improve wear resistance to some extent. The durability has not been fully satisfied. Furthermore, in the case of dispersing the inorganic filler (3), the residual potential is increased by charge carrier traps (usually, hole trapping centers in OPC) existing on the surface of the inorganic filler, and the image density is likely to decrease. There is a tendency. These technologies (1), (2), and (3) are sufficient to satisfy the overall durability including the electrical durability and mechanical durability required for the organic photoreceptor. Has not reached.

  Furthermore, a photoreceptor containing a polyfunctional curable acrylate monomer in order to improve the abrasion resistance and scratch resistance of (1) is also known (Patent Document 4: Japanese Patent No. 3262488). However, in this photoreceptor, although there is a description that the polyfunctional curable acrylate monomer is contained in the protective layer provided on the photosensitive layer, the protective layer may contain a charge transport material. However, when the surface layer contains a low-molecular charge transporting substance, there is a problem of compatibility with the cured product. In some cases, the molecular charge transport material is precipitated and cracks are generated, and the mechanical strength is also lowered. There is also a description that a polycarbonate resin is contained for improving compatibility, but the content of the curable acrylic monomer is reduced, and as a result, sufficient wear resistance cannot be achieved. In addition, regarding a photoconductor that does not include a charge transport material in the surface layer, there is a description that the surface layer is a thin film in order to reduce the potential of the exposed portion. In addition, the environmental stability of the charging potential and the exposure portion potential is poor, and the value fluctuates greatly due to the influence of the greenhouse environment, and the current situation is that a sufficient value has not been maintained.

  As an alternative to wear resistance technology for photosensitive layers, a charge transport layer formed by using a coating solution comprising a monomer having a carbon-carbon double bond, a charge transport material having a carbon-carbon double bond, and a binder resin is used. It is known to be provided (Patent Document 5: Japanese Patent No. 3194392). This binder resin has a carbon-carbon double bond and is reactive with the charge transporting substance, and Those having no double bond and no reactivity are included. This photoconductor is remarkably compatible with wear resistance and good electrical properties. However, when a non-reactive binder resin is used, the binder resin, the monomer, and the charge transport material are used. The compatibility with the cured product produced by this reaction was poor, and surface irregularities were generated during the crosslinking from phase separation, and a tendency to cause poor cleaning was observed. Further, as described above, in this case, the binder resin prevents the curing of the monomer, and what is specifically described as the monomer used in the photoreceptor is a bifunctional one. The monomer has a small number of functional groups and a sufficient crosslinking density cannot be obtained, and it has not yet been satisfactory in terms of wear resistance. Further, even when a reactive binder is used, due to the low number of functional groups contained in the monomer and the binder resin, it is difficult to achieve both the binding amount and the crosslinking density of the charge transport material, and the electrical characteristics and The abrasion resistance was not sufficient.

  In addition, a photosensitive layer containing a compound obtained by curing a hole transporting compound having two or more chain polymerizable functional groups in the same molecule is also known (Patent Document 6: JP 2000-66425 A). However, in this photosensitive layer, the bulky hole transporting compound has two or more chain-polymerizable functional groups, so that distortion occurs in the cured product, resulting in high internal stress, resulting in rough surface layers and cracks over time. It may be easy to do and does not have sufficient durability.

Furthermore, a cross-linked charge transport layer obtained by curing a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure is also known (Patent Document 7: Japanese Patent Application Laid-Open No. 2004-302450, Japanese Patent Application Laid-Open No. 2004-302451, Japanese Patent Application Laid-Open No. 2004-302452 and Japanese Patent Application Laid-Open No. 2005-099688, Japanese Patent Application Laid-Open No. 2005-099688. 2005-107401, Patent Document 12: JP-A-2005-107490, Patent Document 13: JP-A-2005-115322, Patent Document 14: JP-A-2005-140825, Patent Document 15: JP-A-2005-2005. No. 156784, Patent Document 16: JP-A-2005-157026, Patent Document 17: JP-A-2005-1 7297, Patent Document 18: JP 2005-189821 A, Patent Document 19: JP 2005-189828 A, Patent Document 20: JP 2005-189835 A), monofunctional having a charge transporting structure. By using a radically polymerizable compound, cracks in the photosensitive layer are suppressed simultaneously with mechanical and electrical durability. However, there is no description about the acid value in the coating solution, and when an excess acidic compound is present in the coating solution, the effect of oxidizing gases such as ozone and nitrogen oxides generated in the charging step and over a long period of time There is a tendency that electric charges are easily trapped in the cross-linked surface layer due to repeated electric fatigue, and abnormal images such as afterimages may be generated. In the above-mentioned conventional techniques, acrylic compounds and methacrylic compounds are used as radically polymerizable compounds. However, these compounds are inevitably mixed with acidic compounds such as acrylic acid and methacrylic acid in the synthesis route, and the acidic compounds in the coating solution are inevitably excessive, resulting in abnormal images. Had the problem of causing.
For the above reasons, it cannot be said that a photoreceptor having a cross-linked photosensitive layer obtained by chemically bonding the charge transporting structure in these prior arts has sufficient comprehensive characteristics at present.

JP 56-48637 A JP-A 64-1728 JP-A-4-281461 Japanese Patent No. 3262488 Japanese Patent No. 3194392 JP 2000-66425 A JP 2004-302450 A JP 2004-302451 A JP 2004-302452 A Japanese Patent Laying-Open No. 2005-099688 JP-A-2005-107401 JP 2005-107490 A JP-A-2005-115322 JP 2005-140825 A JP 2005-156784 A JP 2005-157026 A JP 2005-157297 A JP 2005-189821 A JP 2005-189828 A JP 2005-189835 A

  An object of the present invention is to provide an electrophotographic photosensitive member that achieves high reliability by achieving both high wear resistance and stable electrical characteristics over a long period of time and extremely reducing the influence of environmental fluctuations. Another object of the present invention is to provide an image forming method, an image forming apparatus, and a process cartridge for the image forming apparatus using the long-life, high-performance photoconductor.

  In the electrophotographic photosensitive member having at least a photosensitive layer on a conductive support, the surface layer of the photosensitive layer is formed by photocuring at least a radical polymerizable compound, and a coating film on the surface layer is formed. It was discovered that the above-mentioned problems can be achieved by setting the acid value of the coating solution used for forming to 0.2 (mg KOH / g) or less, and the present invention has been achieved.

That is, the said subject is solved by (1)-( 19 ) of this invention.
(1) “In a method for producing an electrophotographic photosensitive member having at least a photosensitive layer on a conductive support , a coating solution containing at least a radical polymerizable compound is applied, and the formed coating film is photocured to form a photosensitive member. The coating liquid contains a radical polymerizable compound having a charge transporting structure and a radical polymerizable monomer having no charge transporting structure, and an acid value of 0.2 (mg KOH). / g) or less, the radical polymerizable functional group of the radical polymerizable compound, the method for producing a photoreceptor and acryloyloxy group or a methacryloyloxy group der wherein Rukoto "
( 2 ) "The method for producing an electrophotographic photosensitive member according to ( 1 ) above, wherein the radical polymerizable compound having the charge transporting structure has one radical polymerizable functional group",
( 3 ) "Electrophotographic image according to item ( 1 ) or ( 2 ), wherein the radically polymerizable compound having no charge transporting structure has three or more radically polymerizable functional groups. Photoconductor manufacturing method ",
( 4 ) "Any of the above items (1) to ( 3 ), wherein the photosensitive layer has a layered structure of a charge generation layer, a charge transport layer, and a crosslinked surface layer from the conductive support side." Manufacturing method of electrophotographic photosensitive member according to the description ",
( 5 ) The item (1) above, which includes a step of reducing the acid value of the coating solution for reducing the acid value of the coating solution, wherein the step of reducing the acid value of the coating solution is an adsorption treatment. Thru | or the manufacturing method of the electrophotographic photoreceptor in any one of ( 4 ) term | claims,
( 6 ) "The method for producing an electrophotographic photosensitive member according to ( 5 ) above, wherein the adsorption treatment is to remove an acidic compound present in the coating solution by the adsorption treatment". ,
( 7 ) "Selected from silica gel, acidic alumina, neutral alumina, basic alumina, activated clay, zeolite, silicate, silicon oxide, metal oxide, activated carbon as an active ingredient of the adsorbent used in the adsorption treatment. The method for producing an electrophotographic photosensitive member according to item ( 6 ), wherein at least one kind is used ”,
( 8 ) "The adsorption treatment is an adsorption treatment of a coating solution diluted with the same organic solvent used in the coating solution or an organic solvent having a boiling point lower than that of the organic solvent, Thereafter, the concentrated coating solution by distilling off the solvent, the second (6), characterized in that it comprises an adjusting re concentration preparation step to be the same as an active ingredient the composition ratio of the pre-dilution claim or the (Method for producing electrophotographic photosensitive member according to item ( 7 ) ")
( 9 ) “In an electrophotographic photosensitive member having at least a photosensitive layer on a conductive support , a coating liquid containing at least a radical polymerizable compound is applied, and the formed coating film has a surface layer photocured. There, the coating solution contains a radical-polymerizable monomer having no radical polymerizable compound and the charge transport structure having a charge transport structure, and the acid value is not more than 0.2 (mgKOH / g), the radically polymerizable functional groups of the radical polymerizable compound, an electrophotographic photosensitive member according to acryloyloxy group or a methacryloyloxy group der wherein Rukoto "
( 10 ) "The electrophotographic photosensitive member according to item ( 9 ), wherein the radical polymerizable compound having the charge transporting structure has one radical polymerizable functional group",
( 11 ) The electrophotographic image described in ( 9 ) or ( 10 ) above, wherein the radical polymerizable compound having no charge transporting structure has 3 or more radical polymerizable functional groups. Photoconductor ",
( 12 ) "Any of the above items ( 9 ) to ( 11 ), wherein the photosensitive layer has a laminated structure of a charge generation layer, a charge transport layer, and a crosslinked surface layer from the conductive support side. The electrophotographic photosensitive member described,
( 13 ) "The acid value of 0.2 (mg KOH / g) or less of the coating solution is performed by reducing the acid value of the coating solution, and the method for reducing the acid value of the coating solution is adsorption treatment. The electrophotographic photosensitive member according to any one of ( 9 ) to ( 12 ), wherein:
( 14 ) "The electrophotographic photosensitive member according to item ( 13 ), wherein the adsorption treatment is performed by removing an acidic compound present in the coating solution by the adsorption treatment",
( 15 ) “Selected from silica gel, acidic alumina, neutral alumina, basic alumina, activated clay, zeolite, silicate, silicon oxide, metal oxide, activated carbon as an active ingredient of the adsorbent used in the adsorption treatment. The electrophotographic photosensitive member according to item ( 13 ) or ( 14 ), wherein the electrophotographic photosensitive member is at least one kind or more,
( 16 ) "Effective after dilution by diluting with the same organic solvent used in the coating liquid or with an organic solvent having a boiling point lower than that of the organic solvent, followed by adsorption treatment. The electrophotographic photosensitive member according to any one of ( 13 ) to ( 15 ), wherein the electrophotographic photosensitive member is adjusted to be the same as the component composition ratio and used.
( 17 ) "Image forming method characterized in that at least charging, image exposure, development and transfer are performed using the electrophotographic photosensitive member according to any one of ( 9 ) to ( 16 )" ,
( 18 ) "Image forming apparatus comprising the electrophotographic photosensitive member according to any one of ( 9 ) to ( 16 )",
( 19 ) "At least selected from the group consisting of the electrophotographic photosensitive member according to any one of ( 9 ) to ( 16 ), a charging unit, a developing unit, a transfer unit, a cleaning unit, and a discharging unit. A process cartridge for an image forming apparatus having one means and being detachable from the main body of the image forming apparatus.

  According to the present invention, it is possible to provide an electrophotographic photosensitive member that maintains high durability, has stable electrical characteristics, and is highly reliable, and can provide high-quality image output over a long period of time. It became clear. Further, it has been found that the image forming process, the image forming apparatus, and the process cartridge for the image forming apparatus using the photoconductor of the present invention have high performance and high reliability.

Hereinafter, the present invention will be described in detail.
The present invention is based on the following basic idea. The photoreceptor of the present invention includes a radically polymerizable compound having a charge transporting structure and a radically polymerizable monomer having no charge transporting structure, thereby providing a highly reliable electrophotographic photosensitive material having stable electric characteristics and high wear resistance. The content of the acidic compound in the film of the crosslinked surface layer can be reduced by setting the acid value of the coating liquid for forming the crosslinked surface layer to 0.2 (mg KOH / g) or less. . As a result, polymerization inhibition due to acidic compounds can be sufficiently suppressed, and the amount of acidic compounds that can themselves become charge traps can be reduced. Due to the effects of oxidizing gases such as ozone and nitrogen oxides generated and repeated electrical fatigue over a long period of time, it becomes difficult for trapped charges to be trapped in the crosslinked surface layer. It was possible to achieve reliability.

Next, the radical polymerizable compound used in the present invention will be described.
Of the radically polymerizable compounds used in the present invention, those having a charge transporting structure can be used favorably. The radical polymerizable compound having a charge transporting structure used in the present invention includes a hole transporting structure such as triarylamine, hydrazone, pyrazoline, carbazole, such as condensed polycyclic quinone, diphenoquinone, cyano group and nitro group. It refers to a compound having an electron transporting structure such as an electron withdrawing aromatic ring and having a radical polymerizable functional group. The radical polymerizable functional group may be any group as long as it has a carbon-carbon double bond and can be radically polymerized.

Examples of these radical polymerizable functional groups include 1-substituted ethylene functional groups and 1,1-substituted ethylene functional groups shown below.
(1) Examples of the 1-substituted ethylene functional group include functional groups represented by the following formulas.

〔ただし、式中、Ｘ_１は、置換基を有していてもよいフェニレン基、ナフチレン基等のアリーレン基、置換基を有していてもよいアルケニレン基、−ＣＯ−基、−ＣＯＯ−基、−ＣＯＮ（Ｒ_１０）−基（Ｒ_１０は、水素、メチル基、エチル基等のアルキル基、ベンジル基、ナフチルメチル基、フェネチル基等のアラルキル基、フェニル基、ナフチル基等のアリール基を表わす。）、または−Ｓ−基を表わす。〕
これらの置換基を具体的に例示すると、ビニル基、スチリル基、２−メチル−１，３−ブタジエニル基、ビニルカルボニル基、アクリロイルオキシ基、アクリロイルアミド基、ビニルチオエーテル基等が挙げられる。

[Wherein, X ₁ is an arylene group such as a phenylene group or a naphthylene group optionally having a substituent, an alkenylene group optionally having a substituent, a —CO— group, a —COO— group. , —CON (R ₁₀ ) — group (R ₁₀ represents an alkyl group such as hydrogen, methyl group or ethyl group, an aralkyl group such as benzyl group, naphthylmethyl group or phenethyl group, or an aryl group such as phenyl group or naphthyl group. Or -S- group. ]
Specific examples of these substituents include a vinyl group, a styryl group, a 2-methyl-1,3-butadienyl group, a vinylcarbonyl group, an acryloyloxy group, an acryloylamide group, and a vinyl thioether group.

(2) Examples of the 1,1-substituted ethylene functional group include functional groups represented by the following formulas.

〔ただし、式中、Ｙは、置換基を有していてもよいアルキル基、置換基を有していてもよいアラルキル基、置換基を有していてもよいフェニル基、ナフチル基等のアリール基、ハロゲン原子、シアノ基、ニトロ基、メトキシ基あるいはエトキシ基等のアルコキシ基、−ＣＯＯＲ_１１基（Ｒ_１１は、水素原子、置換基を有していてもよいメチル基、エチル基等のアルキル基、置換基を有していてもよいベンジル、フェネチル基等のアラルキル基、置換基を有していてもよいフェニル基、ナフチル基等のアリール基を表わす。）、または−ＣＯＮＲ_１２Ｒ_１３（Ｒ_１２およびＲ_１３は、水素原子、置換基を有していてもよいメチル基、エチル基等のアルキル基、置換基を有していてもよいベンジル基、ナフチルメチル基、あるいはフェネチル基等のアラルキル基、または置換基を有していてもよいフェニル基、ナフチル基等のアリール基を表わし、互いに同一または異なっていてもよい。）、また、Ｘ_２は上記［化１］式のＸ_１と同一の置換基及び単結合、アルキレン基を表わす。ただし、Ｙ，Ｘ_２の少なくとも何れか一方がオキシカルボニル基、シアノ基、アルケニレン基、及び芳香族環である。〕
これらの置換基を具体的に例示すると、α−塩化アクリロイルオキシ基、メタクリロイルオキシ基、α−シアノエチレン基、α−シアノアクリロイルオキシ基、α−シアノフェニレン基、メタクリロイルアミノ基等が挙げられる。
なお、これらＸ_１、Ｘ_２、Ｙについての置換基にさらに置換される置換基としては、例えばハロゲン原子、ニトロ基、シアノ基、メチル基、エチル基等のアルキル基、メトキシ基、エトキシ基等のアルコキシ基、フェノキシ基等のアリールオキシ基、フェニル基、ナフチル基等のアリール基、ベンジル基、フェネチル基等のアラルキル基等が挙げられる。

[Wherein Y represents an alkyl group which may have a substituent, an aralkyl group which may have a substituent, a phenyl group which may have a substituent, an aryl such as a naphthyl group, etc. Group, halogen atom, cyano group, nitro group, alkoxy group such as methoxy group or ethoxy group, -COOR ₁₁ group (R ₁₁ is a hydrogen atom, an alkyl such as an optionally substituted methyl group or ethyl group) Group, an aralkyl group such as benzyl or phenethyl group which may have a substituent, or an aryl group such as phenyl group or naphthyl group which may have a substituent), or -CONR ₁₂ R ₁₃ ( R ₁₂ and R ₁₃ are hydrogen atoms, which may have a substituent an alkyl group such as methyl group and ethyl group, which may have a substituent group benzyl group, naphthylmethyl group or Fenechi, Aralkyl group or an optionally substituted phenyl group, a group, an aryl group such as a naphthyl group, which may be the same or different from each other.) Further, X ₂ is the Chemical Formula 1] formula Represents the same substituent, single bond, and alkylene group as X _{1 in FIG} . However, Y, at least one oxycarbonyl group in X _2, a cyano group, an alkenylene group, and an aromatic ring. ]
Specific examples of these substituents include an α-acryloyloxy chloride group, a methacryloyloxy group, an α-cyanoethylene group, an α-cyanoacryloyloxy group, an α-cyanophenylene group, and a methacryloylamino group.
In addition, examples of the substituent further substituted with the substituent for X ₁ , X ₂ , and Y include, for example, a halogen atom, a nitro group, a cyano group, a methyl group, an alkyl group such as an ethyl group, a methoxy group, an ethoxy group, and the like And an aryloxy group such as a phenoxy group, an aryl group such as a phenyl group and a naphthyl group, and an aralkyl group such as a benzyl group and a phenethyl group.

  Among these radical polymerizable functional groups, acryloyloxy group and methacryloyloxy group are particularly useful, and compounds having one or more acryloyloxy groups include, for example, compounds having one or more hydroxyl groups in the molecule and acrylic groups. It can be obtained by using an acid (salt), an acrylic acid halide, or an acrylic ester to cause an ester reaction or a transesterification reaction. A compound having one or more methacryloyloxy groups can be obtained in the same manner. Further, the radical polymerizable functional groups in the monomer having two or more radical polymerizable functional groups may be the same or different. Among these radical polymerizable functional groups, an acryloyloxy group and a methacryloyloxy group are particularly useful. The number of radically polymerizable functional groups in one molecule may be one or more, but it is easy to obtain a smooth surface property by suppressing the internal stress of the crosslinked surface layer, and to maintain good electrical characteristics. In general, it is preferred that the number of radically polymerizable functional groups is one. By using such a charge transporting compound having a radical polymerizable functional group, further improvement in durability and stable electrical characteristics for a long period of time were realized. As the charge transporting structure of the charge transporting compound having a radical polymerizable functional group, a triarylamine structure is preferable because of its high mobility, and among them, a compound represented by the following general formula (1) or general formula (2) When is used, electrical characteristics such as sensitivity and residual potential are satisfactorily maintained.

〔式中、Ｒ_１は水素原子、ハロゲン原子、置換基を有してもよいアルキル基、置換基を有してもよいアラルキル基、置換基を有してもよいアリール基、シアノ基、ニトロ基、アルコキシ基、−ＣＯＯＲ_７（Ｒ_７は水素原子、置換基を有してもよいアルキル基、置換基を有してもよいアラルキル基又は置換基を有してもよいアリール基を表わす。）、ハロゲン化カルボニル基若しくはＣＯＮＲ_８Ｒ_９（Ｒ_８及びＲ_９は水素原子、ハロゲン原子、置換基を有してもよいアルキル基、置換基を有してもよいアラルキル基又は置換基を有してもよいアリール基を示し、互いに同一であっても異なっていてもよい。）を表わし、Ａｒ_１、Ａｒ_２は置換もしくは未置換のアリーレン基を表わし、同一であっても異なってもよい。Ａｒ_３、Ａｒ_４は置換もしくは未置換のアリール基を表わし、同一であっても異なってもよい。Ｘは単結合、置換もしくは無置換のアルキレン基、置換もしくは無置換のシクロアルキレン基、置換もしくは無置換のアルキレンエーテル２価基、酸素原子、硫黄原子、ビニレン基を表わす。Ｚは置換もしくは無置換のアルキレン基、置換もしくは無置換のアルキレンエーテル２価基、アルキレンオキシカルボニル２価基を表わす。ｍ、ｎは０〜３の整数を表わす。〕

[Wherein, R ₁ represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a cyano group, a nitro group, A group, an alkoxy group, —COOR ₇ (R ₇ represents a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or an aryl group which may have a substituent. ), A halogenated carbonyl group or CONR ₈ R ₉ (R ₈ and R ₉ have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Represents an aryl group which may be the same or different, and Ar ₁ and Ar ₂ represent a substituted or unsubstituted arylene group, which may be the same or different. . Ar ₃ and Ar ₄ represent a substituted or unsubstituted aryl group, and may be the same or different. X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether divalent group, an oxygen atom, a sulfur atom, or a vinylene group. Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether divalent group, or an alkyleneoxycarbonyl divalent group. m and n represent an integer of 0 to 3. ]

Specific examples of general formula (1) and general formula (2) are shown below.
In the general formula (1) and general formula (2), in the substituent of R ₁ , examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the aryl group include a phenyl group and a naphthyl group. Aralkyl groups include benzyl group, phenethyl group, naphthylmethyl group, alkoxy groups include methoxy group, ethoxy group, propoxy group, etc., and these include halogen atom, nitro group, cyano group, Substituted by alkyl groups such as methyl group, ethyl group, alkoxy groups such as methoxy group and ethoxy group, aryloxy groups such as phenoxy group, aryl groups such as phenyl group and naphthyl group, aralkyl groups such as benzyl group and phenethyl group May be.
Of the substituents for R ₁ , particularly preferred are a hydrogen atom and a methyl group.

Substituted or unsubstituted Ar ₃ and Ar ₄ are aryl groups, and examples of the aryl group include condensed polycyclic hydrocarbon groups, non-fused cyclic hydrocarbon groups, and heterocyclic groups.
The condensed polycyclic hydrocarbon group preferably has 18 or less carbon atoms forming a ring, for example, a pentanyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptaenyl group, a biphenylenyl group, as (asym) -Indacenyl group, s (sym) -indacenyl group, fluorenyl group, acenaphthylenyl group, preadenyl group, acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrenyl group, aceanthrylenyl group , Triphenylyl group, pyrenyl group, chrycenyl group, naphthacenyl group and the like.
Examples of the non-fused cyclic hydrocarbon group include monovalent groups of monocyclic hydrocarbon compounds such as benzene, diphenyl ether, polyethylene diphenyl ether, diphenyl thioether and diphenyl sulfone, or biphenyl, polyphenyl, diphenylalkane, diphenylalkene, diphenylalkyne, Monovalent groups of non-condensed polycyclic hydrocarbon compounds such as triphenylmethane, distyrylbenzene, 1,1-diphenylcycloalkane, polyphenylalkane, and polyphenylalkene, or ring assemblies such as 9,9-diphenylfluorene And monovalent groups of hydrocarbon compounds.
Examples of the heterocyclic group include monovalent groups such as carbazole, dibenzofuran, dibenzothiophene, oxadiazole, and thiadiazole.

The aryl group represented by Ar ₃ or Ar ₄ may have a substituent as shown below, for example.
(1) Halogen atom, cyano group, nitro group and the like.
(2) an alkyl group;
_Preferably, C 1 _{-C 12} especially _C 1 -C _8, more preferably a straight or branched alkyl group of _C 1 -C _4, in the alkyl group a fluorine atom, a hydroxyl group, a cyano group, C ₁ -C ₄ alkoxy group which may have a phenyl group or a halogen _atom, C 1 -C ₄ alkyl or _C 1 -C ₄ phenyl group substituted with an alkoxy group. Specifically, methyl group, ethyl group, n-butyl group, i-propyl group, t-butyl group, s-butyl group, n-propyl group, trifluoromethyl group, 2-hydroxyethyl group, 2-ethoxyethyl Group, 2-cyanoethyl group, 2-methoxyethyl group, benzyl group, 4-chlorobenzyl group, 4-methylbenzyl group, 4-phenylbenzyl group and the like.
(3) an alkoxy group (—OR ₂ );
R ₂ represents the alkyl group defined in (2) above. Specifically, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, t-butoxy group, n-butoxy group, s-butoxy group, i-butoxy group, 2-hydroxyethoxy group, benzyloxy group And a trifluoromethoxy group.
(4) aryloxy group;
Examples of the aryl group include a phenyl group and a naphthyl group. It _may contain an alkoxy group having C 1 -C _4, alkyl group, or a halogen atom C 1 -C ₄ as a substituent. Specific examples include a phenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, a 4-methoxyphenoxy group, and a 4-methylphenoxy group.
(5) an alkyl mercapto group or an aryl mercapto group;
Specific examples include a methylthio group, an ethylthio group, a phenylthio group, and a p-methylphenylthio group.
(6) Substituent represented by the following formula

（式中、Ｒ_３及びＲ_４は各々独立に水素原子、前記（２）で定義したアルキル基、またはアリール基を表わす。アリール基としては、例えばフェニル基、ビフェニル基又はナフチル基が挙げられ、これらはＣ_１〜Ｃ_４のアルコキシ基、Ｃ_１〜Ｃ_４のアルキル基またはハロゲン原子を置換基として含有してもよい。Ｒ_３及びＲ_４は共同で環を形成してもよい）
具体的には、アミノ基、ジエチルアミノ基、Ｎ−メチル−Ｎ−フェニルアミノ基、Ｎ，Ｎ−ジフェニルアミノ基、Ｎ，Ｎ−ジ（トリール）アミノ基、ジベンジルアミノ基、ピペリジノ基、モルホリノ基、ピロリジノ基等が挙げられる。
（７）メチレンジオキシ基、又はメチレンジチオ基等のアルキレンジオキシ基又はアルキレンジチオ基。
（８）置換又は無置換のスチリル基、置換又は無置換のβ−フェニルスチリル基、ジフェニルアミノフェニル基、ジトリルアミノフェニル基等。

(In the formula, R ₃ and R ₄ each independently represent a hydrogen atom, an alkyl group defined in (2) above, or an aryl group. Examples of the aryl group include a phenyl group, a biphenyl group, and a naphthyl group. these may form a ring _C 1 -C ₄ alkoxy _groups, C 1 -C a alkyl group or a halogen atom ₄ which may contain as substituents .R ₃ and _{R 4} jointly)
Specifically, amino group, diethylamino group, N-methyl-N-phenylamino group, N, N-diphenylamino group, N, N-di (tolyl) amino group, dibenzylamino group, piperidino group, morpholino group And pyrrolidino group.
(7) An alkylenedioxy group or an alkylenedithio group such as a methylenedioxy group or a methylenedithio group.
(8) A substituted or unsubstituted styryl group, a substituted or unsubstituted β-phenylstyryl group, a diphenylaminophenyl group, a ditolylaminophenyl group, and the like.

On the other hand, the arylene group represented by Ar ₁ or Ar ₂ is a divalent group derived from the aryl group represented by Ar ₃ or Ar ₄ .

  X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group.

The substituted or unsubstituted alkylene group is a C ₁ -C ₁₂ , preferably C ₁ -C ₈ , more preferably C ₁ -C ₄ linear or branched alkylene group, and these alkylene groups include a fluorine atom, a hydroxyl group, a cyano _group, an alkoxy group of C 1 -C _4, a phenyl group or a halogen _atom, a phenyl group substituted with an alkyl group or a _C 1 -C ₄ alkoxy group C 1 -C ₄ It may be. Specifically, methylene group, ethylene group, n-butylene group, i-propylene group, t-butylene group, s-butylene group, n-propylene group, trifluoromethylene group, 2-hydroxyethylene group, 2-ethoxyethylene Group, 2-cyanoethylene group, 2-methoxyethylene group, benzylidene group, phenylethylene group, 4-chlorophenylethylene group, 4-methylphenylethylene group, 4-biphenylethylene group and the like.

The substituted or unsubstituted cycloalkylene _group, a cyclic alkylene group of C 5 -C _7, these are the cyclic alkylene group fluorine atom, a hydroxyl _group, an alkyl group of C 1 -C _4, a C 1 -C ₄ It may have an alkoxy group. Specific examples include a cyclohexylidene group, a cyclohexylene group, and a 3,3-dimethylcyclohexylidene group.

  Examples of the substituted or unsubstituted alkylene ether divalent group include an alkyleneoxy divalent group such as an ethyleneoxy group and a propyleneoxy group, an alkylenedioxy divalent group derived from ethylene glycol, propylene glycol, and the like, or diethylene glycol, tetra Examples include di- or poly (oxyalkylene) oxy divalent groups derived from ethylene glycol, tripropylene glycol, etc. The alkylene group of the alkylene ether divalent group has a substituent such as a hydroxyl group, a methyl group, or an ethyl group. You may have.

  The vinylene group is

で表わされ、式中、Ｒ_５は水素、アルキル基（前記（２）で定義されるアルキル基と同じ）、アリール基（前記Ａｒ_３、Ａｒ_４で表わされるアリール基と同じ）、ａは１または２、ｂは１〜３を表わす。

In the formula, R ₅ is hydrogen, an alkyl group (the same as the alkyl group defined in (2) above), an aryl group (the same as the aryl group represented by Ar ₃ or Ar ₄ above), and a is 1 or 2, b represents 1-3.

Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether divalent group, or an alkyleneoxycarbonyl group divalent.
Examples of the substituted or unsubstituted alkylene group include the same alkylene groups as those described above for X.
Examples of the substituted or unsubstituted alkylene ether divalent group include the alkylene ether divalent group of X.
Examples of the alkyleneoxycarbonyl divalent group include a caprolactone-modified divalent group.

  Further, the charge transporting compound having a radical polymerizable functional group of the present invention is more preferably a compound having the structure of the following general formula (3).

（式中、ｏ、ｐ、ｑはそれぞれ０又は１の整数、Ｒａは水素原子、メチル基を表わし、Ｒｂ、Ｒｃは水素原子以外の置換基で炭素数１〜６のアルキル基を表わし、複数の場合は異なっても良い。ｓ、ｔは０〜３の整数を表わす。Ｚａは単結合、メチレン基、エチレン基、

(Wherein, o, p and q are each an integer of 0 or 1, Ra represents a hydrogen atom or a methyl group, Rb and Rc represent a substituent other than a hydrogen atom and an alkyl group having 1 to 6 carbon atoms, And s and t each represent an integer of 0 to 3. Za is a single bond, a methylene group, an ethylene group,

を表わす。）
上記一般式で表わされる化合物としては、Ｒｂ、Ｒｃの置換基として、特にメチル基、エチル基である化合物が好ましい。

Represents. )
As the compound represented by the above general formula, compounds having a methyl group or an ethyl group as substituents for Rb and Rc are particularly preferable.

  In the charge transporting compound having a radical polymerizable functional group represented by the general formula (1) and general formula (2), particularly the general formula (3) used in the present invention, the carbon-carbon double bond is opened on both sides. In the polymer that is incorporated into the chain polymer and cross-linked by polymerization with a tri- or higher functional polymerizable monomer, it does not form a terminal structure and exists in the main chain of the polymer. And present in a cross-linked chain between the main chain and the main chain (this cross-linked chain includes an intermolecular cross-linked chain between one polymer and another polymer, and a main chain folded in one polymer. There is an intramolecular cross-linked chain that crosslinks a part of the main chain and another part derived from the polymerized monomer at a position distant from this in the main chain). Even when present in the chain, the triarylamine structure suspended from the chain moiety is It has at least three aryl groups arranged radially from the elementary atoms and is bulky, but it is not directly bonded to the chain part and is suspended from the chain part via a carbonyl group, etc. Since these triarylamine structures can be spatially arranged adjacent to each other in the polymer, there is little structural distortion in the molecule, and the electrophotographic photoreceptor In the case of the surface layer, it is presumed that an intramolecular structure that is relatively free from interruption of the charge transport pathway can be taken.

  In the present invention, the specific acrylic ester compound represented by the following general formula (4) can also be used favorably as a charge transporting compound having a radical polymerizable functional group.

Ａｒ_５は置換又は無置換の芳香族炭化水素骨格からなる一価基または二価基を表わす。芳香族炭化水素としては、ベンゼン、ナフタレン、フェナントレン、ビフェニル、１，２，３，４−テトラヒドロナフタレン等が挙げられる。
置換基としては、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、ベンジル基、ハロゲン原子が挙げられる。また、上記アルキル基、アルコキシ基は、さらにハロゲン原子、フェニル基を置換基として有していても良い。
Ａｒ_６は、少なくとも１個の３級アミノ基を有する芳香族炭化水素骨格からなる一価基または二価基もしくは少なくとも１個の３級アミノ基を有する複素環式化合物骨格からなる一価基または二価基を表わすが、ここで、３級アミノ基を有する芳香族炭化水素骨格とは下記一般式（Ａ）で表わされる。

Ar ₅ represents a monovalent group or a divalent group composed of a substituted or unsubstituted aromatic hydrocarbon skeleton. Examples of the aromatic hydrocarbon include benzene, naphthalene, phenanthrene, biphenyl, 1,2,3,4-tetrahydronaphthalene and the like.
Examples of the substituent include an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a benzyl group, and a halogen atom. The alkyl group and alkoxy group may further have a halogen atom or a phenyl group as a substituent.
Ar ₆ is a monovalent group consisting of an aromatic hydrocarbon skeleton having at least one tertiary amino group, a monovalent group consisting of a divalent group or a heterocyclic compound skeleton having at least one tertiary amino group, or Although it represents a divalent group, the aromatic hydrocarbon skeleton having a tertiary amino group is represented by the following general formula (A).

（式中、Ｒ_１３、Ｒ_１４はアシル基、置換もしくは無置換のアルキル基、置換もしくは無置換のアリール基を表わす。Ａｒ_７はアリール基を表わす。ｗは１〜３の整数を表わす。）

(Wherein R ₁₃ and R ₁₄ represent an acyl group, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Ar ₇ represents an aryl group. W represents an integer of 1 to 3)

Examples of the acyl group for R ₁₃ and R ₁₄ include an acetyl group, a propionyl group, and a benzoyl group.
The substituted or unsubstituted alkyl group for R ₁₃ and R ₁₄ is the same as the alkyl group described for the substituent for Ar ₅ .
The substituted or unsubstituted aryl group of R ₁₃ and R ₁₄ is a phenyl group, a naphthyl group, a biphenylyl group, a terphenylyl group, a pyrenyl group, a fluorenyl group, a 9,9-dimethyl-2-fluorenyl group, an azulenyl group, an anthryl group, In addition to the triphenylenyl group and the chrycenyl group, a group represented by the following general formula (B) can be exemplified.

［式中、Ｂは−Ｏ−、−Ｓ−、−ＳＯ−、−ＳＯ_２−、−ＣＯ−及び以下の２価基から選ばれる。

[Wherein, B is selected from —O—, —S—, —SO—, —SO ₂ —, —CO— and the following divalent groups.

（ここで、Ｒ_２１は、水素原子、Ａｒ_５で定義された置換もしくは無置換のアルキル基、アルコキシ基、ハロゲン原子、Ｒ_１３で定義された置換もしくは無置換のアリール基、アミノ基、ニトロ基、シアノ基を表わし、Ｒ_２２は、水素原子、Ａｒ_５定義された置換もしくは無置換のアルキル基、Ｒ_１３で定義された置換もしくは無置換のアリール基を表わし、ｉは１〜１２の整数、ｊは１〜３の整数を表わす。）］

(Wherein R ₂₁ is a hydrogen atom, a substituted or unsubstituted alkyl group defined by Ar ₅ , an alkoxy group, a halogen atom, a substituted or unsubstituted aryl group defined by R ₁₃ , an amino group, a nitro group; Represents a cyano group, R ₂₂ represents a hydrogen atom, a substituted or unsubstituted alkyl group defined by Ar ₅ , a substituted or unsubstituted aryl group defined by R ₁₃ , and i is an integer of 1 to 12, j represents an integer of 1 to 3)]

Specific examples of the alkoxy group of R ₂₁ include methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, i-butoxy group, s-butoxy group, t-butoxy group, 2-hydroxyethoxy. Group, 2-cyanoethoxy group, benzyloxy group, 4-methylbenzyloxy group, trifluoromethoxy group and the like.
Examples of the halogen atom for R ₂₁ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the amino group of R ₂₁ include a diphenylamino group, a ditolylamino group, a dibenzylamino group, and a 4-methylbenzyl group.
Examples of the aryl group of Ar ₇ include a phenyl group, a naphthyl group, a biphenylyl group, a terphenylyl group, a pyrenyl group, a fluorenyl group, a 9,9-dimethyl-2-fluorenyl group, an azulenyl group, an anthryl group, a triphenylenyl group, and a chrysenyl group. Can do.
Ar ₇ , R ₁₃ and R ₁₄ may have an alkyl group, an alkoxy group or a halogen atom defined by Ar ₅ as a substituent.

Also, heterocyclic compound skeletons having tertiary amino groups include amines such as pyrrole, pyrazole, imidazole, triazole, dioxazole, indole, isoindole, benzimidazole, benzotriazole, benzisoxazine, carbazole, and phenoxazine. Examples include heterocyclic compounds having a structure. These may have an alkyl group, an alkoxy group, or a halogen atom defined by Ar ₅ as a substituent.

B ₁ and B ₂ represent an acryloyloxy group, a methacryloyloxy group, a vinyl group, an acryloyloxy group, a methacryloyloxy group, an alkyl group having a vinyl group, an acryloyloxy group, a methacryloyloxy group, or an alkoxy group having a vinyl group. As the alkyl group and alkoxy group, those described for Ar ₅ are similarly applied. Only _{one of} these B ₁ and B ₂ is present, and both are excluded.

  In the acrylic ester compound of the general formula (4), a compound of the following general formula (5) can be exemplified as a more preferable structure.

式中、Ｒ_８、Ｒ_９は、置換もしくは無置換のアルキル基、置換もしくは無置換のアルコキシ基、ハロゲン原子を表わし、Ａｒ_７、Ａｒ_８は、置換もしくは無置換のアリール基またはアリレン基、置換又は無置換のベンジル基を表わす。アルキル基、アルコキシ基、ハロゲン原子は前記Ａｒ_５で述べたものが同様に適用される。
アリール基は、Ｒ_１３、Ｒ_１４で定義されたアリール基と同様である。アリレン基は、そのアリール基から誘導される二価基である。
Ｂ_１〜Ｂ_４は、一般式（４）におけるＢ_１、Ｂ_２と同様であり、Ｂ_１〜Ｂ_４の内、どれか一つだけが存在し、二つ以上の存在は除外される。ｕは０〜５の整数、ｖは０〜４の整数を表わす。

In the formula, R ₈ and R ₉ represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group or a halogen atom, and Ar ₇ and Ar ₈ represent a substituted or unsubstituted aryl group or an arylene group, substituted Or an unsubstituted benzyl group is represented. As the alkyl group, alkoxy group, and halogen atom, those described for Ar ₅ are similarly applied.
The aryl group is the same as the aryl group defined by R ₁₃ and R ₁₄ . An arylene group is a divalent group derived from the aryl group.
B _{1 to} B ₄ are the same as B ₁ and B ₂ in the general formula (4), and only one of B _{1 to} B ₄ is present, and the presence of two or more is excluded. u represents an integer of 0 to 5, and v represents an integer of 0 to 4.

  The specific acrylic ester compound has the following characteristics. It is a tertiary amine compound having a stilbene-type conjugated structure, and has a developed conjugated system. By using a charge transporting compound with such a conjugated system, the charge injection property at the interface part of the cross-linked layer becomes very good, and intermolecular interaction is inhibited even when immobilized between cross-linked bonds. It is difficult and has good characteristics with respect to charge mobility. Moreover, it has one acryloyloxy group or methacryloyloxy group having high radical polymerizability in the molecule, so that it rapidly gels during radical polymerization and does not cause excessive crosslinking strain. The double bond at the stilbene structure in the molecule partially participates in the polymerization, and the polymerization is lower than the acryloyloxy group or methacryloyloxy group. In addition, since the number of cross-linking reactions per molecular weight can be increased due to the use of double bonds in the molecule, the cross-linking density can be increased and further improvement in wear resistance can be realized. . In addition, the degree of polymerization of this double bond can be adjusted depending on the crosslinking conditions, and an optimum crosslinked film can be easily produced. Such cross-linking participation in radical polymerization is a specific feature of the acrylate compound and does not occur in the α-phenylstilbene type structure as described above.

  From the above, the use of a charge transporting compound having a radical polymerizable functional group represented by the general formula (4), particularly the general formula (5), while maintaining good electrical characteristics and generating cracks and the like A film having an extremely high crosslink density can be formed without causing any defects, thereby satisfying various characteristics of the photoreceptor, and preventing the silica fine particles and the like from being stuck into the photoreceptor, thereby preventing image defects such as white spots. Can be reduced.

  Specific examples of the radically polymerizable compound having a charge transporting structure used in the present invention are shown below, but are not limited to the compounds having these structures.

  The charge transporting compound having a radical polymerizable functional group used in the present invention is important for imparting the charge transport performance of the crosslinked surface layer, and this component is 20 to 80% by weight based on the total amount of the crosslinked surface layer, Preferably, the content of the coating liquid component is adjusted to 30 to 70% by weight. When this component is less than 20% by weight, the charge transport performance of the crosslinked surface layer cannot be maintained sufficiently, and deterioration of electrical characteristics such as a decrease in sensitivity and an increase in residual potential appears with repeated use. On the other hand, if it exceeds 80% by weight, the content of the trifunctional monomer having no charge transport structure is lowered, and the crosslink density is lowered, so that high wear resistance is not exhibited. The required electrical characteristics and wear resistance differ depending on the process to be used, so it cannot be said unconditionally, but considering the balance of both characteristics, the range of 30 to 70% by weight is most preferable.

Next, as the radical polymerizable compound used in the present invention, a radical polymerizable monomer having no charge transporting structure can be used favorably. Examples of the radical polymerizable monomer having no charge transporting structure used in the present invention include those having the radical polymerizable functional group shown in the above radical polymerizable compound having the charge transporting structure. In particular, an acryloyloxy group and a methacryloyloxy group are useful. Further, from the viewpoint of improving wear resistance, a radical polymerizable monomer having three or more radical polymerizable functional groups of acryloyloxy group or methacryloyloxy group can be used effectively.
A compound having three or more acryloyloxy groups is obtained by, for example, using a compound having three or more hydroxyl groups in the molecule, acrylic acid (salt), acrylic acid halide, or acrylic ester, and performing an ester reaction or a transesterification reaction. Obtainable. A compound having three or more methacryloyloxy groups can be obtained in the same manner. Further, the radical polymerizable functional groups in the monomer having three or more radical polymerizable functional groups may be the same or different.

Specific examples of the tri- or higher functional radical polymerizable monomer having no charge transport structure include the following, but are not limited to these compounds.
That is, examples of the radical polymerizable monomer used in the present invention include trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate, HPA-modified trimethylolpropane triacrylate, EO-modified trimethylolpropane triacrylate, and PO-modified. Trimethylolpropane triacrylate, caprolactone modified trimethylolpropane triacrylate, HPA modified trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol triacrylate, ECH modified glycerol triacrylate, EO modified glycerol triacrylate , PO-modified glycerol triacrylate, Lith (acryloxyethyl) isocyanurate, dipentaerythritol hexaacrylate (DPHA), caprolactone-modified dipentaerythritol hexaacrylate, dipentaerythritol hydroxypentaacrylate, alkyl-modified dipentaerythritol pentaacrylate, alkyl-modified dipentaerythritol tetraacrylate, alkyl Modified dipentaerythritol triacrylate, dimethylolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, EO modified phosphoric acid triacrylate, 2,2,5,5-tetrahydroxymethylcyclopentanone tetraacrylate, etc. These may be used alone or in combination of two or more.

  The trifunctional or higher functional radical polymerizable monomer having no charge transport structure used in the present invention is a ratio of molecular weight to the number of functional groups in the monomer in order to form a dense crosslink in the cross-linked surface layer. (Molecular weight / functional group number) is preferably 250 or less. Further, when this ratio is larger than 250, the crosslinked surface layer is soft and wear resistance is somewhat lowered. Therefore, among the monomers exemplified above, monomers having a modifying group such as HPA, EO, and PO are extremely long. It is not preferable to use one having a modifying group alone. Moreover, the component ratio of the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure used for the crosslinked surface layer is 20 to 80% by weight, preferably 30 to 70% by weight, based on the total amount of the crosslinked surface layer. When the monomer component is less than 20% by weight, the three-dimensional cross-linking density of the cross-linked surface layer is small, and a drastic improvement in wear resistance is not achieved as compared with the case of using a conventional thermoplastic binder resin. On the other hand, if it exceeds 80% by weight, the content of the charge transporting compound is lowered, and the electrical characteristics are deteriorated. Since the required wear resistance and electrical characteristics differ depending on the process used, it cannot be said unconditionally, but considering the balance of both characteristics, the range of 30 to 70% by weight is most preferable.

  The crosslinked surface layer of the present invention is an electrophotographic photosensitive member having at least a photosensitive layer on a conductive support, wherein the surface layer of the photosensitive layer photocures at least a radical polymerizable compound. In addition to this, monofunctional and bifunctional radically polymerizable monomers for the purpose of imparting functions such as viscosity adjustment during coating, stress relaxation of the crosslinked surface layer, low surface energy and friction coefficient reduction, etc. Monomers and radically polymerizable oligomers can be used in combination. As these, known ones can be used.

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

  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, and neopentyl glycol diacrylate.

  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 50 parts by weight or less, preferably 30 parts by weight or less, with respect to 100 parts by weight of the tri- or higher functional radical polymerizable monomer.

  Further, the crosslinked surface layer of the present invention is an electrophotographic photoreceptor having at least a photosensitive layer on a conductive support, and the surface layer of the photosensitive layer photocures at least a radical polymerizable compound. The polymerization initiator may be used in the cross-linked surface layer in order to efficiently advance the cross-linking reaction as necessary.

  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, peroxide initiators such as lauroyl peroxide, azobisisobutylnitrile, azobiscyclohexanecarbonitrile Azo initiators such as methyl azobisisobutyrate, azobisisobutylamidine hydrochloride, 4,4′-azobis-4-cyanovaleric acid.

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 and 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, 1, Benzophenone photopolymerization initiators such as 4-benzoylbenzene, thioxanthone photopolymerization initiation such as 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone And other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 2,4,6-trimethylbenzoylpheny Ethoxyphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10- Examples include phenanthrene, acridine compounds, triazine compounds, and imidazole compounds. Moreover, what has a photopolymerization acceleration effect can also be used individually or in combination with the said photoinitiator. Examples thereof include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, 4,4′-dimethylaminobenzophenone, and the like.
These polymerization initiators may be used alone or in combination of two or more. The content of the polymerization initiator is 0.5 to 40 parts by weight, preferably 1 to 20 parts by weight with respect to 100 parts by weight of the total content having radical polymerizability.

  Furthermore, the coating liquid of the present invention can contain additives such as various plasticizers (for the purpose of stress relaxation and adhesion improvement), leveling agents, and low molecular charge transport materials having no radical reactivity as required. 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 weight or less, preferably 10% 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. 3% by weight or less is appropriate.

  Further, as the solvent used in the present invention, a solvent having a saturated vapor pressure of 100 mmHg / 25 ° C. or less is preferable from the viewpoint of improving the adhesion of the crosslinked surface layer. By using such a solvent, the amount of solvent removal at the time of forming the coating film of the crosslinked surface layer is reduced. For this reason, the surface of the underlying photosensitive layer is swollen or slightly dissolved, and the crosslinked surface layer and the photosensitive layer are separated. It is presumed that a continuous region is formed in the vicinity of the interface. By forming such a layer, there is no region with abrupt changes in physical properties between the crosslinked surface layer and the photosensitive layer, the adhesiveness can be sufficiently maintained, and the entire crosslinked surface layer has high durability. It became possible to maintain. In the present invention, the presence of a slight amount of solvent in the coating film during the formation of the coating film accelerates the radical reaction of the crosslinked surface layer by the solvent. As a result, the uniform curing property of the entire crosslinked surface layer is also improved. An electrophotographic photoreceptor that can be improved has been realized. In other words, by diluting with a solvent having a saturated vapor pressure of 100 mmHg / 25 ° C. or less, internal stress inside the crosslinked surface layer is not accumulated locally, and a uniform crosslinked surface layer without distortion can be constructed. In addition, it is possible to realize an electrophotographic photoreceptor having stable electrical characteristics over a long period of time while maintaining high durability over the entire cross-linked surface layer by ensuring sufficient adhesion, and at the same time, cracks do not occur. did it. Further, from the viewpoint of the amount of residual solvent in the coating film during formation, the solvent preferably has a saturated vapor pressure of 50 mmHg / 25 ° C. or less, more preferably 20 mmHg / 25 ° C. or less. Although it is considered to be similar to the effect of saturated vapor pressure, when the boiling point of the solvent is 60 ° C. to 150 ° C., a continuous region between the crosslinked surface layer and the underlying photosensitive layer can be formed satisfactorily. Sufficient sex can be secured. In view of the solvent removal step such as heat drying, the boiling point of the solvent is more preferably 100 ° C. to 130 ° C. Further, in the solvent used in the present invention, when the solubility parameter is 8.5 to 11.0, more preferably 9.0 to 9.7, the coating is made with polycarbonate which is the main constituent material of the lower photosensitive layer. It is possible to construct a cross-linked surface layer that has a higher affinity with the working solution, improves the compatibility of each constituent material at the interface between the cross-linked surface layer and the photosensitive layer, and can maintain sufficient adhesion. It becomes.

  Examples of the solvent used in the present invention include heptane, octane, trimethylpentane, isooctane, nonane, 2,2,5-trimethylhexane, decane, benzene, toluene, xylene, ethylbenzene, isopropylbenzene, styrene, cyclohexane, methylcyclohexane, Hydrocarbons such as ethylcyclohexane and cyclohexene, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3- Pentanol, 2-methyl-1-butanol, tert-pentyl alcohol, 3-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-2-butanol, neopentyl alcohol, -Hexanol, 2-methyl-1-pentanol, 4-methyl-2-pentanol, 2-ethyl-1-butanol, 3-heptanol, allyl alcohol, propargyl alcohol, benzyl alcohol, cyclohexanol, 1,2- Alcohols such as ethanolodiol and 1,2-propanediol, phenols such as phenol and cresol, dipropyl ether, diisopropyl ether, dibutyl ether, butyl vinyl ether, benzyl ethyl ether, dioxane, anisole, phenetole 1,2-epoxybutane Ethers such as acetal, acetals such as 1,2-dimethoxyethane, 1,2-diethoxyethane, methyl ethyl ketone, 2-pentanone, 2-hexanone, 2-heptanone, diisobutylketone, methyl Ketones such as oxide, cyclohexanone, methylcyclohexanone, ethylcyclohexanone, 4-methyl-2-pentanone, acetylacetone, acetonylacetone, ethyl acetate, propyl acetate, butyl acetate, pentyl acetate, 3-methoxybutyl acetate, diethyl carbonate, Esters such as 2-methoxyethyl acetate, halogens such as chlorobenzene, sulfur compounds such as tetrahydrothiophene, or 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, furfuryl alcohol, tetrahydrfurfuryl alcohol 1-methoxy-2-propanol, 1-ethoxy-2-propanol, diacetone alcohol, furfural, 2-methoxyethyl acetate, 2-ethoxyethyl acetate, propylene group Examples thereof include compounds having a plurality of functional groups such as recall propyl ether and propylene glycol-1-monomethyl ether-2-acetate. Among these, from the viewpoint of adhesiveness, butyl acetate, chlorobenzene, acetylacetone, xylene, 2-methoxyethyl acetate, propylene glycol-1-monomethyl ether-2-acetate, and cyclohexanone are preferable. 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 optional, but the amount of residual solvent in the coating film during the coating film formation is maintained, and sufficient adhesion to the crosslinked surface layer From the viewpoint of imparting water, the solid content concentration of the coating liquid is preferably 25% by weight or less, and more preferably 3 to 15% by weight.

  Next, a method for setting the acid value of the coating solution for forming the crosslinked surface layer to 0.2 (mg KOH / g) or less in the present invention will be described in detail. In the present invention, any method in which the acid value of the coating solution is 0.2 (mg KOH / g) or less may be used. Specifically, the method is to reduce the content of acidic compounds in the coating solution. (1) Reduction of the amount of acidic compound using chemical reaction, (2) Removal of acidic compound using adsorbent, and the like. Examples of (1) include neutralization with a basic compound, esterification with an alcohol compound, and acetylation with a glycidyl compound, all of which can be a by-product and can be an impurity that hinders the function as an electrophotographic photoreceptor. Moreover, the radically polymerizable functional group of acrylic acid assumed as a main acidic compound is not treated, and may cause a crosslink inhibition when the crosslinked surface layer is polymerized. Therefore, if it can be confirmed that there is no such side effect, the means (1) is also used favorably. Regarding (2), acidic compounds are separated using adsorption, and ideally only acidic compounds can be removed if there is no contamination by foreign matter due to contact with the adsorbent. Next, (2) will be described in detail.

  In the present invention, the adsorption treatment refers to separating the adsorbent by an operation such as filtration after bringing the coating liquid into contact with the adsorbent. Any adsorbent may be used as long as it adsorbs a polar substance. For example, activated carbon, zeolite, silica gel, activated alumina, activated clay, ion exchange resin, synthetic adsorbent, silicate, silicon oxide, metal oxide, magnesium silicate and the like can be used. For these adsorbents, for example, the adsorbents described in “Adsorption Technology Handbook, Supervisor Hiroshi Shimizu, NTS, 1993” can be used.

  Various grades of activated carbon are known, but care must be taken during use because they have low electrical resistance. When the electrophotographic coating solution was adsorbed with activated carbon, it was found that if the activated carbon remained in the coating solution even a little, the chargeability of the obtained photoreceptor decreased and the characteristics deteriorated. In this case, the activated carbon and the coating solution must be separated using a filter having a pore diameter as small as possible. When a filter having a pore size of 1 μm is used, a decrease in chargeability is recognized, and it is necessary to use a filter having a pore size of at least smaller than that. Therefore, it is not preferable in terms of production efficiency including adsorption processing time. This is a disadvantage compared to other adsorbents.

  Examples of zeolite are well-known names such as trade name molecular sieves, and grades such as 3A, 4A, 5A, and 10A are available depending on the pore size. Any grade can be used in the present invention. Synthetic zeolites are usually in the form of granules of several millimeters, and the separation operation in the adsorption process is generally easy. However, the generation of fine powder is seen in part, and the photoconductor is mixed when this fine powder is mixed in the coating solution. There may be side effects such as lowering of the chargeability and increasing of the residual potential. Therefore, care must be taken during separation.

  On the other hand, silica gel, activated alumina (acidic alumina, basic alumina, neutral alumina), activated clay, silicate, silicon oxide, metal oxide, etc. have almost no effect on the electrical characteristics of the photoreceptor even when a trace amount is mixed. Thus, there is no concern about deterioration of characteristics due to a small amount of contamination, and it is preferably used as an adsorbent used in the adsorption treatment of the present invention. However, a large amount of contamination causes image defects and the like.

  As examples of silica gel, conventionally known ones can be used, but those having as high purity as possible are desired. Those commercially available for column chromatography can be preferably used. For example, Merck silica gel 60 or Wako gel manufactured by Wako Pure Chemical Industries, Ltd. can be used.

  As an example of alumina, a conventionally known one can be used, but one having as high purity as possible is desired. As for silica gel, those commercially available for chromatography can be preferably used. For example, Merck's aluminum oxide (acidic, basic, neutral) can be used.

  As activated clay, what is generally manufactured can be used. For example, activated white clay manufactured and sold by Nippon Active White Earth Co., Ltd., Mizusawa Chemical Industry Co., Ltd., or the like can be used. There are various varieties of these depending on the amount of water, fineness, free acid level, apparent specific gravity, etc., but any varieties can be used. In general, the powdery activated clay has a fineness of 12% or less or 5% or more and a fineness of 80% or more when passing through 200 mesh, and free acid is 2.5 mgKOH / g or less, and the apparent specific gravity is 0.40 to 0. .80 is preferably used. The granular activated clay has a fineness of 15-30 mesh, 30-60 mesh, 8-16 mesh with a water content of 12% or less or 5% or more, and a free acid of 2.5 mgKOH / g or less, Those having an apparent specific gravity of 0.50 to 0.80 are preferably used. Moreover, it is also possible to use a clay mineral acidic clay such as montmorillonite or halloysite which is also used as a raw material for the activated clay.

  Examples of silicates include magnesium silicate and calcium silicate. As those containing magnesium silicate, those commercially available for chromatography like silica gel such as Florisil (made by Wako Pure Chemical Industries) and Tomita AD600 (made by Tomita Pharmaceutical Co., Ltd.) can be preferably used.

  Examples of the metal oxide include sodium oxide, magnesium oxide, calcium oxide and the like in addition to the above-mentioned activated alumina (aluminum oxide). In general, the adsorbent is sold as an active ingredient such as the above-mentioned activated carbon, zeolite, silica gel, silicate, silicon oxide, metal oxide, etc. alone or as a mixture, and a suitable one can be selected. For example, in the case of Florisil, it is a mixture of approximately 15% magnesium silicate and 85% silicon oxide. Moreover, a particle size, a shape, etc. can be used according to the objective.

  As an adsorption treatment method, an adsorbent is added to the coating liquid, and after stirring and mixing, the adsorbent is separated through a filter (contact filtration method) and the coating liquid is passed through a container filled with the adsorbent. A method (fixed layer method) or the like can be applied. Such adsorption treatment methods are described in publicly known literature (for example, “Adsorption Technology Handbook, Supervisor Hiroshi Shimizu, NTS, 1993”). Applicable.

  Next, the adsorption process conditions will be described in more detail. In general, the coating solution for the crosslinked surface layer is often used at a solid content concentration of 3 to 50 wt%. Such a coating liquid may be subjected to an adsorption treatment at the same concentration, or may be diluted in order to facilitate the filtration operation or improve the liquid permeability. The amount of adsorbent varies depending on the type and shape of the adsorbent and the adsorption treatment method. For example, in the case of the contact filtration method, the range is 0.01 wt% to 500 wt% with respect to the solid content of the coating liquid It is preferable to use an adsorbent. For example, when powdered activated clay is used as the adsorbent, a purification effect is seen at 0.1 wt% or more, and a sufficient purification effect is obtained at 10 wt% or more. When using granular activated clay, 1 wt% or more, preferably 10 wt% or more, more preferably 50 wt% or more of the solid content of the coating solution is used. The same applies to other adsorbents. The treatment temperature is an exothermic reaction because the adsorption phenomenon is accompanied by a decrease in internal enthalpy, and high temperatures are likely to cause deterioration of the coating liquid. Since the amount of substances is very small and the processing speed is often limited by the viscosity of the coating liquid that is the liquid to be treated, it is mainly limited by the boiling point and freezing point of the solvent of the coating liquid. Is possible. Usually, it can be arbitrarily selected at -20 ° C to 300 ° C, but it is economically advantageous to carry out at room temperature (-5 ° C to 40 ° C). The contact time can be arbitrarily selected in consideration of the amount ratio of the adsorbent amount and the coating liquid amount, the flow rate and the adsorption speed, but in general, 1 to 30 parts of the adsorbent per 100 parts of the solid content in the coating liquid. It is preferable to contact the adsorbent for 5 minutes or more when the ratio is reached. Furthermore, it is preferably 10 minutes or longer and 20 hours or shorter. If the contact time is too short, the effect does not appear, and if it is too long, side effects such as cleavage of the polymer chain may occur. In the latter case, it is necessary to finish the adsorption process within the allowable range of molecular weight reduction.

  As a result of diligent research on the components contained in the coating liquid of the crosslinked surface layer, the coating liquid mixed with a conventionally known radical polymerizable compound has many acidic compounds obtained as a by-product during the synthesis of the constituent materials. As a result, the acid value of the coating solution was increased. In such a case, due to the influence of an oxidizing gas such as ozone and nitrogen oxide generated in the charging process and repeated electric fatigue over a long period of time, there is a tendency that charges are easily trapped in the cross-linked surface layer, such as afterimages. Abnormal images may occur. In the present invention, the acidic compound can be removed by performing the above-described adsorption treatment on the coating solution for the cross-linked surface layer, the acid value can be reduced to 0.2 (mg KOH / g) or less, and the polymerization inhibition by the acidic compound can be achieved. Ozone and nitrogen oxides generated in the charging process in long-term repetitive use in an actual use environment can be reduced as well as the amount of acidic compounds that can be sufficiently suppressed by themselves. It is possible to suppress the occurrence of abnormal images such as afterimages and achieve higher reliability by making it difficult for charges to be trapped in the cross-linked surface layer due to the effects of oxidizing gases and repeated electrical fatigue over a long period of time. It was possible. In addition, ideally, a state having no acidic compound is desired, so the acid value is 0 (mgKOH / g) in the ideal state, but 0.1 (mgKOH / g) is the lower limit value in consideration of the measurement limit. Can be set.

Next, the method for measuring the acid value in the present invention will be described. The acid value was measured according to the neutralization titration method of JIS-K0070. The number of mg of potassium hydroxide required to neutralize free fatty acid, resin acid, etc. contained in 1 g of coating solution was determined. The acid value was obtained by obtaining. Specifically, 20 g of the coating solution was weighed into a 300 ml Erlenmeyer flask, and 100 ml and JIS K8001 were prepared by mixing diethyl ether specified in JIS-K8103 and ethanol specified in JIS-K8101 at a volume ratio of 1: 1. Add a few drops of the specified phenolphthalein solution and titrate with 0.1 mol / l potassium hydroxide ethanol solution (standardize according to JIS-K8001, JIS-K8574 and JIS-K8102 and the factor is 1). The end point was when the light red color continued for 30 seconds. All the titrations were performed in an environment of a temperature of 23 ° C. and a humidity of 55%. The acid value was calculated by the following formula.
A = B × f × 5.661 / S
A: Acid value B: Amount of 0.1 mol / l potassium hydroxide ethanol solution used for hosting (ml)
f: Factor of 0.1 mol / l potassium hydroxide ethanol solution (1 in the present invention)
S: Mass of the sample

  The crosslinked surface layer of the present invention is an electrophotographic photosensitive member having at least a photosensitive layer on a conductive support, wherein the surface layer of the photosensitive layer photocures at least a radical polymerizable compound. As a coating method, dip coating, spray coating, bead coating, ring coating, etc. can be used, but a spray that can appropriately adjust the amount of residual solvent in the coating film during coating. The coating method can be selected more preferably.

In the present invention, after applying such a coating liquid, light energy is applied from the outside and cured to form a crosslinked surface layer. The image surface static power is 0.53 mW and the exposure energy is 4.0 erg / cm ² . In order to realize a uniform cross-linked surface layer in which the difference between the maximum value and the minimum value of the post-exposure potential is within 30 V when uniform writing is performed, the difference between the maximum value and the minimum value of the photoreceptor surface temperature during light irradiation Has been found to be important to maintain within 30 ° C, preferably within 20 ° C, more preferably within 10 ° C. In order to rapidly advance the polymerization reaction, the surface temperature of the photoreceptor during light irradiation is preferably maintained at 20 ° C. or higher and 170 ° C. or lower. Furthermore, in order to advance the polymerization reaction more efficiently, it has been found that it is important to increase the surface temperature of the photoreceptor by 10 ° C. or more in 30 seconds from the start of light irradiation. Any method may be used as long as the surface temperature of the photoreceptor can be maintained within the above range, but a method of controlling the temperature using a heat medium is preferable. That is, when the photosensitive member is configured using a drum-shaped support, there are methods such as enclosing a heat medium therein and circulating the heat medium. In this case, it is preferable to manage the temperature of the heat medium in order to control the surface temperature of the photoreceptor. Any method may be used to achieve a desired temperature, but for convenience, a method in which temperature management is performed outside the support is preferable to temperature management in the support. Various methods can also be used as a method for uniformly diffusing the heat medium inside the support. However, a mechanism or member for providing a plurality of heat medium inlets into the support or stirring the heat medium inside the support. It is also possible to effectively use the method having Although known means for circulating the heat medium can be used, an existing pump can be used conveniently. Specific examples include a non-volumetric centrifugal pump, a propeller pump, a viscous pump, a positive displacement pump. Examples of the reciprocating pump, the rotary pump, and the like include an injection pump, a bubble pump, a water tank pump, a submersible pump, and a vertical pump. In order to circulate a certain amount of heat medium, a non-positive displacement pump with a constant discharge rate can be used effectively. If the flow rate at this time is too small, there is a possibility of causing temperature unevenness in the longitudinal direction of the electrophotographic photosensitive member. On the other hand, if the flow rate is too large, the increase in the surface temperature of the photosensitive member is small and curing is insufficient. Although there is a possibility, it can be preferably selected from the range of 0.1 to 200 L / min in consideration of the volume inside the support. As the circulation direction of the heat medium, a direction reverse to the convection is preferable considering the convection of the heat medium. Specifically, in the case of a method in which the photosensitive member is arranged and irradiated with light so that the longitudinal direction of the photosensitive member is parallel to the direction of gravitational acceleration in consideration of the coating method and the conveying method of the photosensitive layer, circulation of the heat medium Considering the convection of the heat medium as the direction, the direction from the upper part to the lower part of the photosensitive member is more effective in reducing temperature unevenness in the longitudinal direction of the photosensitive member. As the heat medium, a material that is thermally stable, has a large heat capacity per unit volume and high thermal conductivity is preferably used, and does not corrode the apparatus and is not irritating. Examples of the heat medium include a gaseous heat medium such as air and nitrogen, and an organic heat medium oil such as diphenyl ether and terphenyl, and a liquid heat medium such as water. Thus, an organic heat medium oil or water that is a liquid heat medium is preferable, and water that is easy to handle is particularly preferable. Furthermore, in order to ensure a uniform temperature on the surface of the photoconductor and to ensure a temperature rise from the start of light irradiation, an elastic member is provided inside the support in addition to a method of flowing a heat medium directly inside the support. It is also effective to circulate the heat medium. By using an elastic member, sufficient adhesion to the support can be secured, the surface temperature of the photoconductor can be made uniform, and the temperature rise of the surface of the photoconductor can be controlled by selecting the thermal conductivity of the elastic member. Is possible. From the viewpoint of the degree of stretch and durability of the elastic member, those having a tensile strength of 10 to 400 kg / cm ² and a JIS-A hardness of 10 to 100 can be used effectively. From the viewpoint of the temperature rise rate, the thermal conductivity of the elastic member is preferably 0.1 to 10 W / m · K. Specifically, natural rubber, silicone rubber, fluorosilicone rubber, ethylene / propylene rubber, chloroprene rubber, nitrile rubber, hydrogenated nitrile rubber, butyl rubber, hypalon, acrylic rubber, urethane rubber, fluoro rubber, etc. A heat conductive sheet and a heat conductive film having high heat conductivity are also used favorably. Further, a filter material capable of adjusting the amount of the heat medium in the vicinity of the support inside the support can be used effectively instead of the elastic member. Specifically, generally known filter sheets and sponge materials can be used effectively.

In the present invention, after applying such a coating liquid, light energy is applied from the outside and cured to form a crosslinked surface layer. The light energy used at this time mainly has an emission wavelength in ultraviolet light. Although a UV irradiation light source such as a high-pressure mercury lamp or a metal halide lamp can be used, a visible light source can be selected in accordance with the absorption wavelength of the radical polymerizable substance or the photopolymerization initiator. Irradiation light amount is 50 mW / cm ² or more, preferably 500 mW / cm ² or more, more preferably 1000 mW / cm ² or more. By using irradiation light stronger than 1000 mW / cm ^2, the progress rate of the polymerization reaction is significantly increased, and a more uniform crosslinked surface layer can be formed. In order to perform a uniform polymerization reaction and build a uniform cross-linked surface layer, the illuminance range is 70% or more even if the illuminance at the place where the illuminance on the irradiated object is maximum is 100%. The cross-linked surface layer having uniform characteristics with little unevenness in illuminance can be realized by setting it in the range of preferably 80% or more, more preferably 90% or more. Other external energy can also be used effectively, and besides light, there are heat and radiation. The heat energy is applied by heating from the coating surface side or the support side using a gas such as air or nitrogen, steam, various heat media, infrared rays, or electromagnetic waves. The heating temperature is preferably 100 ° C. or higher and 170 ° C. or lower. If the heating temperature is lower than 100 ° C., the reaction rate is slow and the reaction is not completely completed. At a temperature higher than 170 ° C., the reaction proceeds non-uniformly and a large strain is generated in the crosslinked surface layer. In order to advance the curing reaction uniformly, it is also effective to complete the reaction by heating at a relatively low temperature of less than 100 ° C. and then heating to 100 ° C. or more. Examples of radiation energy include those using electron beams. Among these energies, those using heat and light energy are useful because of easy reaction rate control and simple equipment, and light energy is effective because of easy handling and characteristics of the resulting crosslinked surface layer. .
Since the film thickness of the crosslinked surface layer of the present invention varies depending on the layer structure of the photoreceptor in which the crosslinked surface layer is used, it is described in accordance with the following description of 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.
FIG. 1 is a cross-sectional view showing an electrophotographic photosensitive member of the present invention, in which a single layer structure in which a photosensitive layer (43) having both a charge generating function and a charge transporting function is provided on a conductive support (41). This is a photoconductor. FIG. 1A shows the case where the cross-linked surface layer is the entire photosensitive layer, and FIG. 1-B shows the case where the cross-linked surface layer is the surface portion of the photosensitive layer.
FIG. 2 shows a photoreceptor having a laminated structure in which a charge generation layer (45) having a charge generation function and a charge transport layer (47) having a charge transport material function are laminated on a conductive support (41). is there. FIG. 2-A shows the case where the cross-linked surface layer is the entire charge transport layer, and FIG. 2-B shows the case where the cross-linked surface layer is the surface portion of the charge transport layer.

<About conductive support>
Examples of the conductive support (41) include those having a volume resistance of 10 ¹⁰ Ω · cm or less, for example, metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, oxidation Metal oxide such as indium is deposited or sputtered to form film or cylindrical plastic, paper coated, or aluminum, aluminum alloy, nickel, stainless steel, etc. After conversion, a tube that has been subjected to surface treatment such as cutting, superfinishing, or polishing can be used. Further, an endless nickel belt and an endless stainless steel belt disclosed in JP-A-52-36016 can be used as the conductive support (41).

In addition, a material obtained by dispersing and coating conductive powder in an appropriate binder resin on the support can also be used as the conductive support (41) 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 containing the conductive powder in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, and Teflon (registered trademark) on a suitable cylindrical substrate. Those provided with a conductive layer can also be used favorably as the conductive support (41) 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 a layer having a charge generation function and a charge transport function at the same time.
Hereinafter, each of the photosensitive layer having a laminated structure and the photosensitive layer having a single layer structure will be described.

<Photosensitive layer comprising a charge generation layer and a charge transport layer>
(Charge generation layer)
The charge generation layer (45) 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.

  Binder resins used as necessary for the charge generation layer (45) include polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-. Examples thereof include vinyl carbazole and 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 No. 63-285552, JP-A No. 05-19497, JP-A No. 05-70595, JP-A No. 10-73944, and the like. Illustrated.

The charge generation layer (45) may contain a low molecular charge transport material.
Low molecular charge transport materials that can be used in combination with the charge generation layer (45) 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.

As a method for forming the charge generation layer (45), a vacuum thin film preparation method and a casting method from a solution dispersion system can be mentioned.
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 coating can be performed using a dip coating method, spray coating, bead coating, ring coating method or the like.
The thickness of the charge generation layer provided as described above is suitably about 0.01 to 5 μm, preferably 0.05 to 2 μm.

(About charge transport layer)
The charge transport layer (47) is a layer having a charge transport function, and the crosslinked surface layer having the charge transport structure of the present invention is useful as a charge transport layer. When the cross-linked surface layer is the entire charge transport layer (47), the radical polymerizable composition (charge transport structure of the present invention is formed on the charge generation layer (45) as described in the above cross-linked surface layer preparation method. A coating liquid containing a radically polymerizable monomer and a charge transporting compound having a radically polymerizable functional group (the same applies hereinafter) is applied, and if necessary, after drying, a curing reaction is initiated by external energy to form 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.
When the cross-linked surface layer is formed on the surface portion of the charge transport layer (47) and the charge transport layer (47) has a laminated structure, the lower layer portion of the charge transport layer has a charge transport material having a charge transport function and a binder. The resin is dissolved or dispersed in a suitable solvent, and this is formed on the charge generation layer (45) by coating and drying, and a coating solution containing the radical polymerizable composition of the present invention is coated thereon. Then, it is crosslinked and cured by external energy.
As the charge transport material, the electron transport material, hole transport material and polymer charge transport material described in the charge generation layer (45) can be used. As described above, the use of the polymer charge transport material can reduce the solubility of the lower layer when the surface layer is applied, and is particularly useful.

As the binder resin, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, 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, 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 weight, preferably 40 to 150 parts by weight, based on 100 parts by weight 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 lower layer portion of the charge transport layer, the same solvent as that 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 lower layer portion of the charge transport layer can be formed by a coating method similar to that for the charge generation layer (45).

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

  When the cross-linked surface layer is the surface portion of the charge transport layer (47), the radical polymerizable composition of the present invention is contained on the lower layer portion of the charge transport layer as described in the method for preparing the cross-linked surface layer. After the coating liquid is applied and dried as necessary, a curing reaction is initiated by external energy such as heat or light to form a crosslinked surface layer. At this time, the film thickness of the crosslinked surface layer is 1 to 20 μm, preferably 2 to 10 μm. If the thickness is less than 1 μm, the durability varies due to uneven film thickness. If the thickness is more than 20 μm, the entire thickness of the charge transport layer is increased, and the reproducibility of the image is reduced due to the diffusion of charges.

<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, and the crosslinked surface layer having the charge transport structure of the present invention contains a charge generation material having a charge generation function, thereby providing a single layer structure. It is useful as a photosensitive layer. As described in the method for forming a charge generation layer, the charge generation material is dispersed together with a coating solution containing a radical polymerizable composition, applied onto the charge generation layer (45), and dried if necessary. The curing reaction is initiated by external energy, and a crosslinked surface layer is formed. In addition, you may add the liquid in which the charge generation material was previously disperse | distributed with the solvent to this coating material for bridge | crosslinking surface layers. At this time, the film thickness of the crosslinked surface layer is 10 to 30 μm, preferably 10 to 25 μm. If the thickness is less than 10 μm, a sufficient charging potential cannot be maintained. If the thickness is more than 30 μm, peeling from the conductive substrate or the undercoat layer tends to occur due to volume shrinkage during curing.

  Further, when the crosslinked surface layer is a surface portion of a photosensitive layer having a single layer structure, the lower layer portion of the photosensitive layer is composed of a charge generating material having a charge generating function, a charge transporting material having a charge transport function, and a binder resin in an appropriate solvent. It can be formed by dissolving or dispersing in, coating and drying. 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 (45) and the charge transport layer (47). As the binder resin, in addition to the binder resin previously mentioned in the section of the charge transport layer (47), a binder resin mentioned in the charge generation layer (45) may be mixed and used. In addition, the above-described polymer charge transport materials can also be used, which is useful in that contamination of the lower photosensitive layer composition into the crosslinked surface layer can be reduced. The thickness of the lower layer portion of the photosensitive layer is suitably about 5 to 30 μm, preferably about 10 to 25 μm.

When the cross-linked surface layer is the surface portion of the photosensitive layer having a single layer structure, the coating solution containing the radical polymerizable composition of the present invention and the charge generating material is applied onto the lower layer portion of the photosensitive layer as described above. If necessary, after drying, it is cured by external energy such as heat or light to form a crosslinked surface layer. At this time, the film thickness of the crosslinked surface layer is 1 to 20 μm, preferably 2 to 10 μm. When the thickness is less than 1 μm, the durability varies due to the film thickness unevenness.
The charge generation material contained in the photosensitive layer having a single layer structure is preferably 1 to 30% by weight based on the total amount of the photosensitive layer, and the binder resin contained in the lower layer portion of the photosensitive layer is 20 to 80% by weight of the total amount. The transport material is preferably used in an amount of 10 to 70 parts by weight.

<About the intermediate layer>
In the photoreceptor of the present invention, when the crosslinked surface layer is the surface portion of the photosensitive layer, it is possible to provide an intermediate layer for the purpose of suppressing mixing of lower layer components into the crosslinked surface layer or improving adhesion with the lower layer. is there. This intermediate layer prevents inhibition of the curing reaction and unevenness of the crosslinked surface layer caused by mixing of the lower photosensitive layer composition in the outermost surface layer containing the radical polymerizable composition. It is also possible to improve the adhesion between the lower photosensitive layer and the surface cross-linked 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 (41) 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 anodization, organic substances 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>
In the present invention, in order to improve environmental resistance, in order to prevent a decrease in sensitivity and an increase in residual potential, a surface cross-linked layer, a photosensitive layer, a charge generation layer, a charge transport layer, an undercoat layer, an intermediate layer An antioxidant can be added to each layer such as a 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, ditetradecyl-3,3′-thiodipropionate, and the like.

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

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

<Image Forming Method and Apparatus>
Next, the image forming apparatus of the present invention will be described in detail with reference to the drawings.
FIG. 3 is a schematic diagram for explaining the image forming process and the image forming apparatus of the present invention, and modifications as described below also belong to the category of the present invention.
In FIG. 3, the photoreceptor (21) comprises at least a photosensitive layer and a specific protective layer provided on a conductive support, and the photosensitive layer contains a charge transport material represented by the general formula (1). Become. Although the photoconductor has a drum shape, it may have a sheet shape or an endless belt shape. A charging roller (23), a pre-transfer charger (27), a transfer charger (30), a separation charger (31), and a pre-cleaning charger (33) include a corotron, a scorotron, a solid state charger, and charging. Known means such as a roller and a transfer roller are used.

  Among these charging methods, a contact charging method or a non-contact proximity arrangement method is particularly desirable. The contact charging method has advantages such as high charging efficiency, a small amount of ozone generation, and downsizing of the apparatus. The contact-type charging member here is a type in which the surface of the charging member is in contact with the surface of the photosensitive member, and includes a charging roller, a charging blade, and a charging brush. Of these, charging rollers and charging brushes are used favorably.

  Further, the charging member arranged in the proximity is a type in which the charging member is arranged in a non-contact state so as to have a gap (gap) of 200 μm or less between the surface of the photoreceptor and the charging member surface. It is distinguished from known chargers represented by corotron and scorotron from the distance of the gap. The adjacently arranged charging member used in the present invention may have any shape as long as it has a mechanism capable of appropriately controlling the gap with the surface of the photoreceptor. For example, the rotation shaft of the photosensitive member and the rotation shaft of the charging member may be mechanically fixed so as to have an appropriate gap. Among them, using a charging member in the shape of a charging roller, a gap forming member is disposed at both ends of the non-image forming portion of the charging member, and only this portion is brought into contact with the surface of the photoreceptor, and the image forming region is disposed in a non-contact manner. Alternatively, the gap forming member at both ends of the non-photosensitive portion of the photoconductor is disposed, and only this portion is brought into contact with the surface of the charging member, and the image forming region is disposed in a non-contact manner, so that the gap can be stably stabilized. It is a method that can be maintained. In particular, the methods described in JP-A Nos. 2002-148904 and 2002-148905 can be used satisfactorily. An example of the proximity charging mechanism in which the gap forming member is disposed on the charging member side is shown in FIG. By using the above-mentioned method, there are advantages such as high charging efficiency and low ozone generation, miniaturization of the apparatus, no contamination with toner, etc., and no mechanical wear due to contact. Because it is used well. Furthermore, as an application method, there is an advantage that uneven charging is less likely to occur by using AC superposition, and it can be used satisfactorily.

  When such a contact type charging member or a non-contact charging type charging member is used, there is a drawback that dielectric breakdown of the photosensitive member is likely to occur. However, the photoreceptor used in the present invention has an intermediate layer composed of a laminate structure of a charge blocking layer and a moire preventing layer, and further, the photosensitive layer does not contain coarse particles of a charge generating substance. Extremely high pressure resistance. For this reason, the resistance against the dielectric breakdown of the photosensitive member is high, and the merit (prevention of uneven charging) of the charging member can be utilized.

  Although the photosensitive member is charged by such a charging member, in a normal image forming apparatus, since background contamination due to the photosensitive member is likely to occur, the electric field strength applied to the photosensitive member is set to be low ( 40V / μm or less, preferably 30V / μm or less). This is because the occurrence of soiling depends on the electric field strength, and the probability of soiling increases as the electric field strength increases. However, reducing the electric field strength applied to the photoreceptor reduces the efficiency of photocarrier generation and reduces the photosensitivity. In addition, since the electric field strength applied between the surface of the photosensitive member and the conductive support is reduced, the straightness of the photocarrier generated in the photosensitive layer is reduced, and diffusion due to clone repulsion is increased, resulting in a reduction in resolution. Arise. On the other hand, by using the electrophotographic photosensitive member of the present invention, it is possible to extremely reduce the probability of background contamination, so there is no need to reduce the electric field intensity more than necessary, and it can be used even under an electric field intensity of 40 V / μm or more. become able to. For this reason, a sufficient amount of gain in the attenuation of the photoreceptor light can be secured, a large margin can be created for the later-described development (potential), and development can be performed without reducing the resolution.

The image exposure unit (25) uses a light source capable of ensuring high brightness, such as a light emitting diode (LED), a semiconductor laser (LD), or electroluminescence (EL).
Use light sources such as fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light emitting diodes (LEDs), semiconductor lasers (LD), and electroluminescence (EL) as light sources such as static elimination lamps (22). Can do. 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.
Among these light sources, light emitting diodes and semiconductor lasers have high irradiation energy and long wavelength light of 600 to 800 nm, so that the above-mentioned phthalocyanine pigment, which is a charge generation material, exhibits high sensitivity and is used well. The Such a light source or the like irradiates the photosensitive member with light by providing a process such as a transfer process, a charge eliminating process, a cleaning process, or a pre-exposure using light irradiation in addition to the process shown in FIG.

The toner developed on the photoconductor (21) by the developing unit (26) is transferred to the transfer paper (29), but not all is transferred and remains on the photoconductor (21). Toner is also produced. Such toner is removed from the photoreceptor by the fur brush (34) and the blade (35). Cleaning may be performed only with a cleaning brush, and a known brush such as a fur brush or a mag fur brush is used as the cleaning brush.
When the electrophotographic 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. If this is developed with toner of negative (positive) polarity (electrodetection fine particles), a positive image can be obtained, and if developed with toner of positive (negative) polarity, a negative image can be obtained. A known method is applied to the developing unit, and a known method is also used for the charge eliminating unit.

FIG. 5 shows another example of an electrophotographic process according to the present invention. The photoreceptor (61) is formed by providing at least a photosensitive layer and a specific protective layer on a conductive support, and the photosensitive layer contains a charge transport material represented by the general formula (1). Driven by driving rollers (62a) and (62b), charged by a charger (63), image exposure by a light source (64), development (not shown), transfer using a charger (65), by a light source (66) Exposure before cleaning, cleaning with a brush (67), and static elimination with a light source (68) are repeated.
The above illustrated electrophotographic process is illustrative of an embodiment of the present invention, and of course other embodiments are possible. For example, in FIG. 5, the pre-cleaning exposure is performed from the support side, but this may be performed from the photosensitive layer side, or irradiation with static elimination light may be performed from the support side.
On the other hand, the light irradiation process is illustrated as image exposure, pre-cleaning exposure, and charge-removing exposure. Irradiation can also be performed.

  The image forming means as described above may be fixedly incorporated in a copying apparatus, a facsimile, or a printer, but may be incorporated in these apparatuses in the form of a process cartridge. A process cartridge is a single device (part) that contains a photoconductor and further includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, a neutralizing unit, and the like. There are many shapes and the like of the process cartridge, but a general example is shown in FIG. The photoreceptor (76) is formed by providing at least a photosensitive layer and a specific protective layer on a conductive support, and the photosensitive layer contains a charge transport material represented by the general formula (1).

FIG. 7 is a schematic diagram for explaining the tandem-type full-color electrophotographic apparatus of the present invention, and the following modifications also belong to the category of the present invention.
In FIG. 7, reference numerals (1C), (1M), (1Y), and (1K) denote drum-shaped photoconductors, and the photoconductors are provided with at least a photoconductive layer and a specific protective layer on a conductive support. The photosensitive layer contains a charge transport material represented by the general formula (1).
The photoreceptors (1C), (1M), (1Y), (1K) rotate in the direction of the arrow in the figure, and charging members (2C), (2M), (2Y), (2K) at least in the order of rotation therearound. ), Developing members (4C), (4M), (4Y), (4K), and cleaning members (5C), (5M), (5Y), (5K). The charging members (2C), (2M), (2Y), and (2K) are charging members that constitute a charging device for uniformly charging the surface of the photoreceptor. From the photosensitive member surface side between the charging members (2C), (2M), (2Y), (2K) and the developing members (4C), (4M), (4Y), (4K), from an exposure member (not shown). Laser beams (3C), (3M), (3Y), and (3K) are irradiated so that an electrostatic latent image is formed on the photoreceptors (1C), (1M), (1Y), and (1K). It has become. Then, the four image forming elements (6C), (6M), (6Y), and (6K) centering on such photoconductors (1C), (1M), (1Y), and (1K) are transferred materials. They are juxtaposed along a transfer conveyance belt (10) that is a conveyance means. The transfer conveyance belt (10) includes developing members (4C), (4M), (4Y), (4K) and cleaning members (5C) of the image forming units (6C), (6M), (6Y), (6K). , (5M), (5Y), and (5K) are in contact with the photoreceptors (1C), (1M), (1Y), and (1K), and are in contact with the back side on the photoreceptor side of the transfer conveyance belt (10). Transfer brushes (11C), (11M), (11Y), and (11K) for applying a transfer bias are arranged on the surface (back surface). Each of the image forming elements (6C), (6M), (6Y), and (6K) is different in the color of the toner inside the developing device, and the others are the same in configuration.

  In the color electrophotographic apparatus having the configuration shown in FIG. 7, the image forming operation is performed as follows. First, in each of the image forming elements (6C), (6M), (6Y), (6K), the photoconductors (1C), (1M), (1Y), (1K) are in the direction indicated by the arrow (the direction along with the photoconductor). ) Are rotated by charging members (2C), (2M), (2Y), (2K) that are rotated, and laser beams (3C), (3M) are then exposed by an exposure unit (not shown) disposed outside the photoreceptor. ), (3Y), and (3K) form an electrostatic latent image corresponding to each color image to be created. Next, the latent image is developed by the developing members (4C), (4M), (4Y), and (4K) to form a toner image. Development members (4C), (4M), (4Y), and (4K) are development members that perform development with toners of C (cyan), M (magenta), Y (yellow), and K (black), respectively. The toner images of the respective colors formed on the two photoconductors (1C), (1M), (1Y), and (1K) are superimposed on the transfer paper. The transfer paper (7) is fed out from the tray by the paper feed roller (8), temporarily stopped by the pair of registration rollers (9), and is transferred to the transfer conveyance belt (10) in synchronism with the image formation on the photosensitive member. Sent. The transfer paper (7) held on the transfer conveyance belt (10) is conveyed, and each color is in contact position (transfer section) with each photoconductor (1C), (1M), (1Y), (1K). The toner image is transferred. The toner image on the photoconductor is transferred to the transfer brush (11C), (11M), (11Y), (11K) and the photoconductor (1C), (1M), (1Y), (1K). The image is transferred onto the transfer paper (7) by an electric field formed from the potential difference. Then, the recording paper (7) on which the toner images of four colors are superimposed through the four transfer portions is conveyed to the fixing device (12), where the toner is fixed, and is discharged to a paper discharge portion (not shown). Further, residual toner remaining on the photosensitive members (1C), (1M), (1Y), and (1K) without being transferred by the transfer unit is removed from the cleaning devices (5C), (5M), (5Y), ( 5K). In the example of FIG. 7, the image forming elements are arranged in the order of C (cyan), M (magenta), Y (yellow), and K (black) from the upstream side to the downstream side in the transfer paper conveyance direction. However, it is not limited to this order, and the color order is arbitrarily set. Further, when creating a black-only document, it is particularly effective to use the present invention to provide a mechanism that stops the image forming elements (6C), (6M), and (6Y) other than black. Further, in FIG. 7, the charging member is in contact with the photosensitive member. By using a charging mechanism as shown in FIG. 4, an appropriate gap (about 10 to 200 μm) is provided between them. In addition, the wear amount of the both can be reduced, and toner filming on the charging member can be reduced and the toner can be used satisfactorily.

  The image forming means as described above may be fixedly incorporated in a copying apparatus, facsimile, or printer, but each electrophotographic element may be incorporated in the apparatus in the form of a process cartridge. A process cartridge is a single device (part) that contains a photoconductor and further includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, a neutralizing unit, and the like.

<Synthesis example of monofunctional radically polymerizable compound having charge transporting structure>
The compound having a charge transporting structure in the present invention is synthesized, for example, by the method described in Japanese Patent No. 3164426. An example of this is shown below.
(1) Synthesis of hydroxy group-substituted triarylamine compound (the following structural formula B) 113.85 g (0.3 mol) of a methoxy group-substituted triarylamine compound (the following structural formula A) and 138 g (0.92 mol) of sodium iodide To this, 240 ml of sulfolane was added and heated to 60 ° C. in a nitrogen stream. In this solution, 99 g (0.91 mol) of trimethylchlorosilane was added dropwise over 1 hour and stirred at a temperature of about 60 ° C. for 4 and a half hours to complete the reaction. About 1.5 L of toluene was added to the reaction solution, cooled to room temperature, and washed repeatedly with water and an aqueous sodium carbonate solution. Thereafter, the solvent was removed from the toluene solution and purified by column chromatography (adsorption medium: silica gel, developing solvent: toluene: ethyl acetate = 20: 1). Cyclohexane was added to the obtained pale yellow oil to precipitate crystals. In this way, 88.1 g (yield = 80.4%) of white crystals of the following structural formula B was obtained.
The melting point is 64.0 to 66.0 ° C., and the elemental analysis value (%) is shown in the following table.

(2) Synthesis of Triarylamino Group-Substituted Acrylate Compound (Exemplary Compound No. 1 in Table 1) 82.9 g (0.227 mol) of the hydroxy group-substituted triarylamine compound (Structural Formula B) obtained in (1) above ) Was dissolved in 400 ml of tetrahydrofuran, and an aqueous sodium hydroxide solution (NaOH: 12.4 g, water: 100 ml) was added dropwise in a nitrogen stream. The solution was cooled to 5 ° C., and 25.2 g (0.272 mol) of acrylic acid chloride was added dropwise over 40 minutes. Then, it stirred at 5 degreeC for 3 hours, and reaction was complete | finished. The reaction solution was poured into water and extracted with toluene. This extract was repeatedly washed with an aqueous sodium bicarbonate solution and water. Thereafter, the solvent was removed from the toluene solution and purified by column chromatography (adsorption medium: silica gel, developing solvent: toluene). N-Hexane was added to the obtained colorless oil to precipitate crystals. Thus, Exemplified Compound No. 80.73 g (yield = 84.8%) of 1 white crystal was obtained.
The melting point is 117.5 to 119.0 ° C., and the elemental analysis value (%) is shown in the following table.

(3) Synthesis example of acrylic ester compound (Preparation of diethyl 2-hydroxybenzylphosphonate)
Into a reaction vessel equipped with a stirrer, thermometer, and dropping funnel, 38.4 g of 2-hydroxybenzyl alcohol (manufactured by Tokyo Chemical Industry) and 80 ml of o-xylene are placed, and triethyl phosphite (manufactured by Tokyo Chemical Industry Co., Ltd.) in a nitrogen stream. 62.8 g was slowly added dropwise at 80 ° C., and the reaction was further carried out at the same temperature for 1 hour. Thereafter, the produced ethanol, the solvent o-xylene, and unreacted triethyl phosphite were removed by distillation under reduced pressure to obtain 66 g of diethyl 2-hydroxybenzylphosphonate. (Yield 90%, boiling point 120.0 ° C./1.5 mmHg)

(Preparation of 2-hydroxy-4 ′-(N, N-bis (4-methylphenyl) amino) stilbene)
Into a reaction vessel equipped with a stirrer, a thermometer, and a dropping funnel, 14.8 g of potassium tert-butoxide and 50 ml of tetrahydrofuran were placed. Under a nitrogen stream, 9.90 g of diethyl 2-hydroxybenzylphosphonate and 4- (N, N A solution in which 5.44 g of -bis (4-methylphenyl) amino) benzaldehyde was dissolved in tetrahydrofuran was slowly added dropwise at room temperature, and then reacted at the same temperature for 2 hours. Thereafter, water was added under water cooling, and then 2N hydrochloric acid aqueous solution was added for acidification. Tetrahydrofuran was removed by an evaporator, and the crude product was extracted with toluene. The toluene phase was washed with water, an aqueous sodium hydrogen carbonate solution and saturated brine in this order, and dehydrated by adding magnesium sulfate. After filtration, toluene was removed to obtain an oily crude product, which was further purified with silica gel and then crystallized in hexane to give 5.09 g of 2-hydroxy-4 ′-(N, N-bis). (4-Methylphenyl) amino) stilbene was obtained. (Yield 72%, melting point 136.0-138.0 ° C.)

(Preparation of 4 ′-(N, N-bis (4-methylphenyl) amino) stilben-2-yl acrylate)
In a reaction vessel equipped with a stirrer, a thermometer, and a dropping funnel, 14.9 g of 2-hydroxy-4 ′-(N, N-bis (4-methylphenyl) amino) stilbene, 100 ml of tetrahydrofuran, 12% concentration of hydroxide 21.5 g of an aqueous sodium solution was added, and 5.17 g of acrylic acid chloride was added dropwise over 5 minutes at 5 ° C. under a nitrogen stream. Then, it was made to react at the same temperature for 3 hours. The reaction solution was poured into water, extracted with toluene, concentrated and subjected to column purification with silica gel. The obtained crude product was recrystallized with ethanol, and yellow needle-like 4 ′-(N, N-bis (4-methylphenyl) amino) stilben-2-yl acrylate (Exemplary Compound No. 34) 13. 5 g was obtained. (Yield 79.8%, melting point 104.1-105.2 ° C.)
Elemental analysis values (%) are shown below.

  As described above, a number of 2-hydroxystilbene derivatives are synthesized by reacting 2-hydroxybenzylphosphonic acid ester derivatives with various amino-substituted benzaldehyde derivatives, and acrylation or methacrylation is carried out to produce various acrylic acids. An ester compound can be synthesized.

EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited to a following example.
<Overview>
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 20 μm charge transport layer were formed. A coating solution for a crosslinked surface layer having the following composition is spray-coated on the charge transport layer, and the irradiation time is 150 seconds using a Fusion UV lamp system (a configuration diagram of the lamp system is shown in FIG. 9). Was irradiated with light and further dried at 130 ° C. for 20 minutes to provide a 7 μm surface cross-linked layer to obtain an electrophotographic photoreceptor of the present invention. Note that “parts” used in the examples all represent parts by weight.

Example 1
[Coating liquid for undercoat layer]
Alkyd resin: 6 parts (Beckosol 1307-60-EL, manufactured by Dainippon Ink & Chemicals, Inc.)
Melamine resin: 4 parts (Super Becamine G-821-60, manufactured by Dainippon Ink & Chemicals, Inc.)
Titanium oxide: 40 parts Methyl ethyl ketone: 50 parts

[Coating liquid for charge generation layer]
Bisazo pigment of the following structural formula (I): 2.5 parts

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

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

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

テトラヒドロフラン：１００部
１％に希釈したシリコーンオイルのテトラヒドロフラン溶液：０．２部
（ＫＦ５０−１００ＣＳ、信越化学工業製）

Tetrahydrofuran: 100 parts Tetrahydrofuran solution of silicone oil diluted to 1%: 0.2 parts (KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

[Coating liquid for cross-linked surface layer]
After mixing the following described materials, the following adsorption treatment was performed to prepare a coating solution.
(1) Material: Radical polymerizable compound having a charge transporting structure: 10 parts [Exemplary Compound No. 54. (Molecular weight: 419, number of functional groups: 1)
Radical polymerizable monomer having no charge transporting structure: 10 parts [KAYARAD TMPTA (manufactured by Nippon Kayaku, functional group number: trifunctional)]
Photopolymerization initiator: 1 part (Irgacure 184, manufactured by Nippon Kayaku)
Solvent: 120 parts a. Tetrahydrofuran: 90 parts b. Butyl acetate: 30 parts

(2) Adsorption treatment The above coating solution is diluted with 141 parts of dichloromethane, and 10.5 parts of silica gel (Wako Pure Chemical Industries, Wakogel C-300) is added as an adsorbent, corresponding to 50% of the solid content. Stir. Thereafter, the solution was filtered under pressure using a 0.1 μm membrane filter, the solvent was distilled off with an evaporator, and the solution was returned to 141 parts of the original coating solution after concentration.

[Light irradiation conditions and temperature control method]
Fusion UV lamp system (irradiation light illumination: 3300 W / cm ² )
Irradiation chamber atmosphere: Heat medium under air: Water (Flow rate: 3.5 L / min, Circulation direction: From top to bottom of photoconductor)
Elastic member: None

Example 2
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the coating solution for the crosslinked surface layer of Example 1 was changed as follows.
(1) Material Radical polymerizable compound having a charge transporting structure: 10 parts [Exemplary Compound No. 50 (molecular weight: 586, number of functional groups: 1)]
Radical polymerizable monomer having no charge transport structure: 10 parts a. KAYARAD TMPTA (manufactured by Nippon Kayaku, number of functional groups: trifunctional): 5 parts b. KAYARAD DPHA (Nippon Kayaku, functional group number: 5.5 functional): 5 parts Photopolymerization initiator: 1 part (Irgacure 184, Nippon Kayaku)
Solvent: 120 parts a. Tetrahydrofuran: 90 parts b. Butyl acetate: 30 parts (2) Adsorption treatment Adsorption treatment was carried out in the same manner as in Example 1 except that acidic alumina (Merck 1078 activity I) was used as the adsorbent.

Example 3
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the coating solution for the crosslinked surface layer of Example 1 was changed as follows.
(1) Material Radical polymerizable compound having a charge transporting structure: 10 parts [Exemplary Compound No. 109 (molecular weight: 445, functional group number: 1 functional)]
Radical polymerizable monomer having no charge transport structure: 10 parts a. SR-350 (manufactured by Nippon Kayaku, number of functional groups: trifunctional): 5 parts b. KAYARAD DPCA-120 (Nippon Kayaku, functional group number: 6): 5 parts Photopolymerization initiator: 1 part (Kayacure CTX, Nippon Kayaku)
Solvent: 120 parts a. Tetrahydrofuran: 90 parts b. Butyl acetate: 30 parts (2) Adsorption treatment Adsorption treatment was carried out in the same manner as in Example 1 except that basic alumina (1076 activity I manufactured by Merck) was used as the adsorbent.

Example 4
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the coating solution for the crosslinked surface layer of Example 1 was changed as follows.
(1) Material Radical polymerizable compound having a charge transporting structure: 10 parts [Exemplary Compound No. 160 (molecular weight: 385, number of functional groups: bifunctional)]
Radical polymerizable monomer having no charge transport structure: 10 parts [KAYARAD DPCA-120 (manufactured by Nippon Kayaku, functional group number: 6 functions)]
Photopolymerization initiator: 1 part (Irgacure 819, manufactured by Nippon Kayaku)
Solvent: 120 parts a. Tetrahydrofuran: 90 parts b. Butyl acetate: 30 parts (2) Adsorption treatment Adsorption treatment was carried out in the same manner as in Example 1 except that basic alumina (1076 activity I manufactured by Merck) was used as the adsorbent.

Example 5
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the coating solution for the crosslinked surface layer of Example 1 was changed as follows.
(1) Material Radical polymerizable compound having a charge transporting structure: 10 parts [Exemplary Compound No. 165 (molecular weight: 455, number of functional groups: trifunctional)]
Radical polymerizable monomer having no charge transport structure: 10 parts a. KAYARAD DPCA-120 (manufactured by Nippon Kayaku, number of functional groups: 6 functional): 5 parts b. M-225 (manufactured by Toa Gosei, number of functional groups: 2 functional): 5 parts Photopolymerization initiator: 1 part (Irgacure 819, manufactured by Nippon Kayaku)
Solvent: 120 parts a. Tetrahydrofuran: 90 parts b. Butyl acetate: 30 parts (2) Adsorption treatment Adsorption treatment was carried out in the same manner as in Example 1 except that activated clay (powder reagent manufactured by Wako Pure Chemical Industries, Ltd.) was used as the adsorbent.

Example 6
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the coating solution for the crosslinked surface layer of Example 1 was changed as follows.
(1) Material Radical polymerizable compound having a charge transporting structure: 10 parts [Exemplary Compound No. 54 (molecular weight: 419, number of functional groups: 1)]
Radical polymerizable monomer having no charge transport structure: 10 parts a. KAYARAD DPCA-120 (manufactured by Nippon Kayaku, number of functional groups: 6 functional): 5 parts b. SR-295 (made by Kayaku Sartomer, number of functional groups: 4): 5 parts Photopolymerization initiator: 1 part (Irgacure 819, made by Nippon Kayaku)
Solvent: 120 parts (tetrahydrofuran)
(2) Adsorption treatment Adsorption treatment was performed in the same manner as in Example 1 except that Florisil (a fine granular reagent manufactured by Wako Pure Chemical Industries, Ltd.) was used as the adsorbent.

Example 7
An electrophotographic photosensitive member was produced in the same manner as in Example 5 except that the amount of activated clay in Example 5 was changed to 0.21 part corresponding to 1% of the solid part.

Example 8
An electrophotographic photosensitive member was produced in the same manner as in Example 5 except that the amount of activated clay in Example 5 was changed to 1.05 parts corresponding to 5% of the solid part.

Example 9
An electrophotographic photosensitive member was produced in the same manner as in Example 5 except that the amount of activated clay in Example 5 was changed to 2.1 parts corresponding to 10% of the solid part.

Example 10
An electrophotographic photosensitive member was produced in the same manner as in Example 5 except that the amount of activated clay in Example 5 was changed to 4.2 parts corresponding to 20% of the solid part.

Example 11
An electrophotography similar to Example 1 except that acrylic acid (manufactured by Toa Gosei) was added to the coating solution for the crosslinked surface layer in Example 1 and the acid value of the coating solution was changed to 0.20 (mgKOH / g). A photoconductor was prepared.

Comparative Example 1
An electrophotographic photosensitive member was produced in the same manner as in Example 5 except that the adsorption treatment of the coating solution for the crosslinked surface layer was not performed in Example 5.

Comparative Example 2
Electrophotography as in Example 1 except that acrylic acid (manufactured by Toa Gosei) was added to the coating solution for the crosslinked surface layer in Example 1 and the acid value of the coating solution was changed to 0.3 (mgKOH / g). A photoconductor was prepared.

Comparative Example 3
Electrophotography as in Example 1 except that acrylic acid (manufactured by Toa Gosei) was added to the coating solution for the crosslinked surface layer in Example 1 and the acid value of the coating solution was changed to 0.5 (mgKOH / g). A photoconductor was prepared.

Comparative Example 4
An electrophotographic photoreceptor in the same manner as in Example 1 except that acrylic acid (manufactured by Toa Gosei) was added to the coating solution for the crosslinked surface layer in Example 1 and the acid value of the coating solution was changed to 5 (mgKOH / g). Was made.

Comparative Example 5
An electrophotographic photoreceptor as in Example 1 except that acrylic acid (manufactured by Toa Gosei) was added to the coating solution for the crosslinked surface layer in Example 1 and the acid value of the coating solution was changed to 20 (mgKOH / g). Was made.

Comparative Example 6
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the crosslinked surface layer was not provided in Example 1 and the thickness of the charge transporting layer was 27 μm.

Comparative Example 7
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the constituent materials of the coating solution for the crosslinked surface layer in Example 1 were changed as follows.
(1) Material Radical polymerizable monomer having no charge transporting structure: 20 parts [KAYARAD TMPTA (manufactured by Nippon Kayaku, functional group number: trifunctional)]
Photopolymerization initiator: 1 part (Irgacure 184, manufactured by Nippon Kayaku)
Solvent: 120 parts a. Tetrahydrofuran: 90 parts b. Butyl acetate: 30 parts

Comparative Example 8
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the constituent materials of the coating solution for the crosslinked surface layer in Example 1 were changed as follows.
(1) Material: Radical polymerizable compound having a charge transporting structure: 20 parts [Exemplary Compound No. 54 (molecular weight: 419, number of functional groups: 1)]
Photopolymerization initiator: 1 part (Irgacure 184, manufactured by Nippon Kayaku)
Solvent: 120 parts a. Tetrahydrofuran: 90 parts b. Butyl acetate: 30 parts

Comparative Example 9
An electrophotographic method as in Example 1 except that acrylic acid (manufactured by Toa Gosei) was added to the coating solution for the crosslinked surface layer in Example 1 and the acid value of the coating solution was changed to 0.21 (mgKOH / g). A photoconductor was prepared.

(Acid value measuring method)
The acid values of the crosslinked surface layer coating solutions of Examples 1 to 11 and Comparative Examples 1 to 9 prepared as described above were measured. As a method, 20 g of the coating solution was weighed into a 300 ml Erlenmeyer flask, and 100 ml and JIS K8001 were prepared by mixing diethyl ether specified in JIS-K8103 and ethanol specified in JIS-K8101 at a volume ratio of 1: 1. Add a few drops of phenolphthalein solution, titrate with 0.1 mol / l potassium hydroxide ethanol solution (standardize according to JIS-K8001, JIS-K8574 and JIS-K8102 and adjust the factor to 1) and dilute the indicator The end point was when the red color lasted for 30 seconds. All the titrations were performed in an environment of a temperature of 23 ° C. and a humidity of 55%. The acid value was calculated by the following formula.
A = B × f × 5.661 / S
A: Acid value B: Amount of 0.1 mol / l potassium hydroxide ethanol solution used for hosting (ml)
f: Factor of 0.1 mol / l potassium hydroxide ethanol solution (1 in the present invention)
S: Mass of the sample

(Image evaluation 1)
The photoconductors of Examples 1 to 11 and Comparative Examples 1 to 9 manufactured as described above are mounted on a process cartridge as shown in FIG. 6, mounted in an image forming apparatus as shown in FIG. 3, and an image exposure light source is used. A 780 nm semiconductor laser (image writing by a polygon mirror), a scorotron charger as a charging member, a transfer belt as a transfer member, and a 655 nm LED as a static elimination light source were used. The application bias to the charging member and the amount of light of the semiconductor laser were set so that the process conditions before the test were as follows, and a chart with a writing rate of 6% ) Was printed on continuous 70,000 sheets.
(Process conditions before testing)
Photoconductor charging potential (unexposed portion potential): -900V
Development bias: -650V
Surface potential of exposed area at development site: -100V

Evaluation was performed by measuring the unexposed portion of the photoreceptor before and after printing 70,000 images. As a measuring method, a surface potential meter is mounted at the developing portion position shown in FIG. 3, each photoconductor is fixed to an applied bias charged to −900 V in the initial state, and the surface potential of the unexposed portion at the developing portion position is determined. It was measured. In addition, the photosensitive member exposed portion potential of about 70,000 sheets was evaluated. In the measuring method, a surface potential meter is mounted at the developing portion position shown in FIG. 3, each photoconductor is fixed to an applied bias charged to −900 V in the initial state, and the exposed portion surface potential at the developing portion position is measured. .
Also, the difference in the photoreceptor film thickness (that is, the amount of wear of the photoreceptor) before and after all tests was evaluated. The film thickness was measured at intervals of 1 cm, excluding 5 cm at both ends in the longitudinal direction of the photoreceptor, and the average value was taken as the film thickness. The results are shown in Table 5.

  It can be seen that in the examples of the present invention, high wear resistance is realized while maintaining good electrostatic characteristics. In Comparative Example 6 in which no cross-linked surface layer was provided and Comparative Example 8 in which the cross-linked surface layer did not contain a radical polymerizable monomer, the amount of wear after printing 70,000 sheets was large, and sufficient wear resistance was obtained. Not done. In Comparative Example 7 in which the cross-linked surface layer does not have a charge transporting structure, the exposed portion potential is high from the beginning, and the electrophotographic photosensitive member characteristics are not satisfied.

(Image evaluation 2)
The previously prepared photoreceptors of Examples 1 to 11 and Comparative Examples 1 to 5 and 9 are mounted on a process cartridge as shown in FIG. 6 and mounted on a tandem type full color image forming apparatus as shown in FIG. The exposure light source was a semiconductor laser of 780 nm (image writing using a polygon mirror), a scorotron charger as a charging member, a transfer belt as a transfer member, and a 655 nm LED as a charge removal light source. The process conditions before the test were set as follows.
(Process conditions before testing)
Photoconductor charging potential (unexposed portion potential): -700 V
Development bias: -500V
Surface potential of exposed area at development site: -100V

In the evaluation, the images shown in FIG. 8 were output before and after gas exposure under the following conditions, and the degree of afterimage in the halftone portion was evaluated. Very good ones were indicated by ◎, good ones were indicated by ○, slightly inferior ones were indicated by Δ, and very bad ones were indicated by ×. Further, after the gas exposure, an ISO / JIS-SCID image N1 (portrait) was output and the color color reproducibility was evaluated. The color reproducibility evaluation was carried out in 4 stages. Very good ones were indicated by ◎, good ones were indicated by ○, slightly inferior ones by Δ, inferior ones by ▲, and very bad ones by x. The results are shown in Table 6.
(Gas exposure conditions)
NOx exposure was performed for 7 days in an environment of nitric oxide concentration: 50 ppm, nitrogen dioxide concentration: 25 ppm, temperature of 40 ° C., and relative humidity of 55% using a Directec NOx exposure test apparatus.

なお、実施例の吸着処理前の酸価は以下のとおりでる。

In addition, the acid value before the adsorption process of an Example is as follows.

In the embodiment of the present invention, a highly reliable electrophotographic photosensitive member is obtained which has good afterimage and color balance results even after gas exposure and is not affected by environmental fluctuations. That is, an electrophotographic photosensitive member has been realized that has achieved high wear resistance, good electrical characteristics, and high stability over a long period of time. On the other hand, in Comparative Examples 1 to 5 and 9 having an acid value of 0.2 or more, image characteristics such as afterimage and color balance after gas exposure are deteriorated, and a highly reliable electrophotographic photosensitive member cannot be realized.
Accordingly, in an electrophotographic photoreceptor having at least a photosensitive layer on a conductive support, the surface layer of the photosensitive layer is formed by photocuring at least a radical polymerizable compound, and a coating film of the surface layer is formed. By maintaining the acid value of the coating solution used in the coating solution at 0.2 (mgKOH / g) or less, high durability is maintained, stable electric characteristics, and a highly reliable electrophotographic photoreceptor is realized. Thus, it has become clear that an electrophotographic photosensitive member capable of realizing high-quality image output over a long period of time can be provided. Further, it has been found that the image forming process, the image forming apparatus, and the process cartridge for the image forming apparatus using the photoconductor of the present invention have high performance and high reliability.

1 is a cross-sectional view illustrating an example of an electrophotographic photosensitive member of the present invention. It is sectional drawing which shows the other example of the electrophotographic photoreceptor of this invention. It is the schematic for demonstrating the image forming process and image forming apparatus of this invention. It is the schematic which shows a proximity charging mechanism. It is another schematic diagram for explaining an image forming process of the present invention. It is the schematic which shows an example of the process cartridge of this invention. 1 is a schematic view for explaining a tandem full-color electrophotographic apparatus of the present invention. It is the image for evaluation used in the Example. It is a block diagram of the lamp system used in the Example.

Explanation of symbols

(About Figures 1 and 2)
41 Conductive Support 43 Photosensitive Layer 45 Charge Generation Layer 47 Charge Transport Layer (Regarding FIG. 3)
21 Photoconductor 22 Static elimination lamp 23 Charging member 25 Image exposure unit 26 Development unit 27 Pre-transfer charger 28 Registration roller 29 Transfer paper 30 Transfer charger 31 Separation charger 32 Separation claw 33 Pre-cleaning charger 34 Fur brush 35 Blade (FIG. 4)
50 Photoconductor 51 Charging roller 52 Gap forming member 53 Metal shaft 54 Image forming area 55 Non-image forming area (about FIG. 5)
61 Photosensitive member 62a Driving roller 62b Driving roller 63 Charging charger 64 Image exposure source 65 Transfer charger 66 Pre-cleaning exposure 67 Cleaning brush 68 Static elimination light source (about FIG. 6)
76 photoconductor 77 charging charger 78 cleaning brush 79 image exposure unit 80 developing roller (about FIG. 7)
1C, 1M, 1Y, 1K Drum-shaped photosensitive member 2C, 2M, 2Y, 2K Charging member 3C, 3M, 3Y, 3K Laser light 4C, 4M, 4Y, 4K Developing member 5C, 5M, 5Y, 5K Cleaning member 6C, 6M , 6Y, 6K Image forming element 7 Transfer paper 8 Paper feed roller 9 Registration roller 10 Transfer conveying belt 11C, 11M, 11Y, 11K Transfer brush 12 Fixing device

Claims (19)

In a method for producing an electrophotographic photosensitive member having at least a photosensitive layer on a conductive support , a coating liquid containing at least a radical polymerizable compound is applied, and the formed coating film is photocured to form a surface layer of the photosensitive member. The coating liquid includes a radical polymerizable compound having a charge transporting structure and a radical polymerizable monomer having no charge transporting structure, and an acid value of 0.2 (mg KOH / g) or less. , and the radical polymerizable functional group of the radical polymerizable compound, acryloyloxy group or methacryloyloxy method of producing an electrophotographic photosensitive member according to group der wherein Rukoto. 2. The method for producing an electrophotographic photosensitive member according to claim 1 , wherein the radical polymerizable compound having the charge transporting structure has one radical polymerizable functional group. The method for producing an electrophotographic photosensitive member according to claim 1 or 2, wherein the radically polymerizable functional groups of the radical polymerizable compound not having charge transport structure is 3 or more. The charge generating layer photosensitive layer is a conductive support side, a charge transport layer, the manufacturing method of the electrophotographic photosensitive member according to any one of claims 1 to 3, characterized in that a laminated structure of a cross-linked surface layer. Wherein said comprises a coating liquid having an acid value of an acid value reduction step of coating solution to reduce any of claims 1 to 4, wherein the acid value reduction step of coating liquid is adsorption treatment A method for producing an electrophotographic photoreceptor. 6. The method for producing an electrophotographic photosensitive member according to claim 5 , wherein the adsorption treatment removes an acidic compound present in the coating solution by the adsorption treatment. As an active ingredient of the adsorbent used in the adsorption treatment, at least one selected from silica gel, acidic alumina, neutral alumina, basic alumina, activated clay, zeolite, silicate, silicon oxide, metal oxide, activated carbon The method for producing an electrophotographic photosensitive member according to claim 6 , wherein: The adsorption treatment is an adsorption treatment of a coating solution diluted with the same organic solvent used in the coating solution or an organic solvent having a boiling point lower than that of the organic solvent. concentration of the coating solution by evaporation, electrophotographic photosensitive member according to claim 6 or 7, characterized in that it comprises an adjusting re concentration preparation step to be the same as an active ingredient the composition ratio before dilution Manufacturing method. An electrophotographic photosensitive member comprising at least a photosensitive layer on a conductive support, which has a surface layer coating liquid was coated and the formed coating film photocured comprising at least a radically polymerizable compound, the coating The working solution contains a radical polymerizable compound having a charge transporting structure and a radical polymerizable monomer not having a charge transporting structure, and has an acid value of 0.2 (mg KOH / g) or less, and the radical polymerizable compound the radical polymerizable functional group, an electrophotographic photosensitive member according to acryloyloxy group or a methacryloyloxy group der wherein Rukoto. 10. The electrophotographic photoreceptor according to claim 9 , wherein the radical polymerizable compound having the charge transporting structure has one radical polymerizable functional group. The electrophotographic photosensitive member according to claim 9 or 10 , wherein the radical polymerizable compound having no charge transporting structure has three or more radical polymerizable functional groups. The electrophotographic photosensitive member according to claim 9, wherein the photosensitive layer has a laminated structure of a charge generation layer, a charge transport layer, and a crosslinked surface layer from the conductive support side. The acid value of 0.2 (mg KOH / g) or less of the coating solution is performed by reducing the acid value of the coating solution, and the method for reducing the acid value of the coating solution is adsorption treatment. The electrophotographic photosensitive member according to claim 9 . The electrophotographic photosensitive member according to claim 13 , wherein the adsorption treatment is performed by removing an acidic compound present in the coating solution by the adsorption treatment. As an active ingredient of the adsorbent used in the adsorption treatment, at least one selected from silica gel, acidic alumina, neutral alumina, basic alumina, activated clay, zeolite, silicate, silicon oxide, metal oxide, activated carbon The electrophotographic photosensitive member according to claim 13 or 14 , wherein It is diluted with the same organic solvent as used in the coating liquid, or an organic solvent having a boiling point lower than that of the organic solvent, and is subjected to adsorption treatment, and then concentrated by distilling off the solvent. The electrophotographic photosensitive member according to claim 13 , wherein the electrophotographic photosensitive member is adjusted to be the same and used. An image forming method, wherein at least charging, image exposure, development, and transfer are performed using the electrophotographic photosensitive member according to claim 9 . An image forming apparatus comprising the electrophotographic photosensitive member according to claim 9 . An electrophotographic photosensitive member according to any one of claims 9 to 16 , and at least one means selected from the group consisting of a charging means, a developing means, a transfer means, a cleaning means, and a charge eliminating means, A process cartridge for an image forming apparatus, wherein the process cartridge is removable from a main body of the forming apparatus.

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