JP2008070553A - Image forming apparatus and process cartridge for image formation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus and a process cartridge for image formation which maintain high durability, avoid occurrence of an abnormal image in high-speed repeated use, and can output images in a stable state. <P>SOLUTION: The image forming apparatus is equipped with an electrophotographic photoreceptor, and a latent electrostatic image forming unit, a developing unit, a transferring unit and a fixing unit arranged above the photoreceptor, wherein the transferring unit is a roller or belt transferring unit configured to apply a positive electric potential to the photoreceptor, and the electrophotographic photoreceptor has a layer structure obtained by sequentially stacking on a conductive support a photosensitive layer and a surface layer formed by hardening a trifunctional or more radical polymerizable monomer having no charge transporting structure and a radical polymerizable compound having a charge transporting structure with a light energy illuminating unit. A compound having both of a hindered phenol structure and a hindered amine structure is contained in the surface layer, and the concentration of the compound having both of the hindered phenol structure and the hindered amine structure is varied in between the surface part and the inner part of the surface layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member having high durability and high image quality over a long period of time by using a surface photosensitive layer having high wear resistance and good electrical characteristics. The present invention also relates to an image forming method, an image forming apparatus, and an image forming process cartridge using those long-life, high-performance photoconductors.

  In recent years, the development of information processing system machines using electrophotography has been remarkable, and in particular, laser printers and digital copying machines that record information with light by converting information into digital signals have significantly improved print quality and reliability. . These laser printers and digital copiers that are rapidly spreading are required to have higher speed and smaller size as well as higher image quality. Furthermore, recently, the demand for full-color laser printers and full-color digital copiers capable of full-color printing is rapidly increasing. When full-color printing is performed, it is necessary to superimpose toner images of at least four colors. Therefore, it is particularly important to increase the speed and size of the apparatus. In order to realize high speed and downsizing of the apparatus, it is necessary to improve the sensitivity of the electrophotographic photosensitive member used for them and to reduce the diameter of the photosensitive member. In particular, in the case of a tandem system effective for achieving both full color and high speed, since at least four photoreceptors are included in the apparatus, the degree of demand for reducing the diameter of the photoreceptor is very high. However, as the diameter of the photoconductor is reduced, the photoconductor is used in a harsher situation. Therefore, the replacement speed of the conventional photoconductor is greatly increased, especially in a high-speed machine. It becomes a serious problem. Therefore, in order to realize high speed and downsizing of the apparatus, it is indispensable not only to increase the sensitivity of the photoconductor used at the same time but also to greatly increase the durability.

  In an image forming apparatus that operates at a high speed, a system that directly transfers a toner image formed on a photoreceptor to a recording medium is often used as a transfer unit. In this method, the recording medium is transported by a belt, brought into contact with or close to the surface of the photosensitive member, and a sufficient bias is applied from the back side of the recording medium to transfer the toner image from the photosensitive member surface to the recording medium. Transition. In an image forming apparatus that operates at a high speed, the machine design requires a high linear speed, and the transfer bias becomes very large in order to increase transfer efficiency. As a result, even when the hazard applied to the photoconductor corresponding to the portion where the toner is developed and the portion where the toner is not developed acts through the recording medium, an abnormal image is generated. When the polarity of the transfer bias is opposite to that of the photosensitive member, if the transfer bias is charged to the opposite polarity to that of the photosensitive member, this potential cannot be canceled by light neutralization and the previous static The history of the electrostatic latent image remains and a negative afterimage is generated.

  A charge generating material having a high quantum efficiency is indispensable for increasing the sensitivity of the photoreceptor required to cope with the higher speed of the apparatus. As an organic high-sensitivity photoreceptor, titanyl phthalocyanine having a diffraction peak (± 0.2 °) with a Bragg angle 2θ of at least 27.2 in the XRD (CuKα ray (wavelength 1.542 mm)) is used as the charge generating material. Is widely used and is very effective.

  In order to increase the durability of the photoreceptor, it is necessary to improve the stability of the image quality and particularly to suppress the occurrence of background stains. As a mechanism for the occurrence of scumming, when the photosensitive member is charged, a charge having a polarity opposite to that induced on the conductive support side leaks locally and is injected into the photosensitive layer and the surface of the photosensitive member. This is considered to be due to the fact that the portion is easily developed. Two major factors that affect image quality in repeated use of the photoreceptor are electrostatic fatigue of the photoreceptor and wear of the photoreceptor. In the former, fatigue of the photoconductor progresses due to repeated charging and exposure in image formation, and a decrease in charging potential or an increase in exposed portion potential caused thereby causes a decrease in image quality. In particular, the decrease in the charging potential further increases the influence of the leakage of charges from the conductive support, and makes it easy to reveal the background stains. In the latter case, when the surface layer of the photoconductor is worn by rubbing the cleaning member and the like, and the film thickness of the photoconductor surface layer is reduced, the image quality is improved due to an increase in charge intensity or an increase in the number of scratches on the photoconductor surface. Causes a drop. In particular, when the electric field strength increases due to the decrease in the film thickness, the occurrence of background contamination is remarkably increased.

  For this reason, the charge transport layer or protective layer formed on the outermost surface of the photoreceptor has been devised to increase the wear resistance. Techniques for improving the abrasion resistance of the photosensitive layer include (i) a method using a curable binder in the cross-linked charge transport layer (see, for example, Patent Document 1: Japanese Patent Laid-Open No. 56-48637), (ii) A material using a polymeric charge transport material (for example, see Patent Document 2: Japanese Patent Laid-Open No. 64-1728), (iii) A material in which an inorganic filler is dispersed in a cross-linked charge transport layer (for example, Patent Document 3) : See JP-A-4-281461). As described above, since the fluctuation of the electric field strength with time can be reduced by increasing the wear resistance of the photoreceptor, a high effect can be obtained for the suppression of background contamination.

  However, among these technologies, those using the curable binder (i) have a poor residual potential due to poor compatibility with the charge transport material and impurities such as polymerization initiators and unreacted residues. There is a tendency for image density reduction to occur easily. In addition, although the polymer type charge transport material (ii) can improve the abrasion resistance to some extent, it has not yet fully satisfied the durability required for the organic photoreceptor. . In addition, polymer charge transport materials are difficult to polymerize and purify, and it is difficult to obtain a high-purity material. Therefore, it is difficult to stabilize electrical characteristics between materials. Furthermore, it may cause problems in production such as a high viscosity of the coating liquid. The dispersion of the inorganic filler (iii) exhibits higher abrasion resistance than a photoreceptor in which a normal low molecular charge transport material is dispersed in an inert polymer, but the charge present on the surface of the inorganic filler. The residual potential increases due to trapping, and the image density tends to decrease. Further, when the unevenness of the inorganic filler and the binder resin on the surface of the photoconductor is large, a cleaning failure may occur, which may cause toner filming or image flow. These technologies (i), (ii), and (iii) have defects in residual potential and cleanability even if they may be effective in suppressing scumming. I have not been satisfied enough.

  Furthermore, a photoreceptor containing a polyfunctional acrylate monomer cured product in order to improve the abrasion resistance and scratch resistance of (i) is also known (see, for example, Patent Document 4: Japanese Patent No. 3262488). However, in this photoreceptor, although there is a description that the polyfunctional acrylate monomer cured product is contained in the protective layer provided on the photosensitive layer, the protective layer may contain a charge transport material. However, there is a problem of compatibility with the cured product when a cross-linked charge transport layer contains a low molecular charge transport material. As a result, precipitation of a low-molecular charge transport material and white turbidity occur, and not only the image density is lowered but also the mechanical strength is lowered due to the increase of the exposed portion potential. Furthermore, since this photoconductor specifically reacts with the monomer in a state containing a polymer binder, the three-dimensional network structure does not proceed sufficiently, and the crosslink density becomes dilute, resulting in dramatic wear resistance. It has not yet been achieved.

  As a wear resistance technique for the photosensitive layer related to this, 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. It is known to provide (for example, refer to Patent Document 5: Japanese Patent No. 3194392). This binder resin is thought to play a role of improving the adhesion between the charge generation layer and the curable charge transport layer, and further mitigating the internal stress of the film during thick film curing, and has a carbon-carbon double bond. These are roughly classified into those having reactivity with the charge transporting substance and those having no reactivity with the double bond. 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 is poor, and layer separation occurs in the cross-linked charge transport layer, which may cause scratches and sticking of external additives and paper powder in the toner. In addition, as described above, the three-dimensional network structure does not proceed sufficiently and the cross-linking density becomes dilute, so that it has not reached the point where dramatic wear resistance can be exhibited. In addition, those described as the above-mentioned monomers used in this photoreceptor are bifunctional and have not yet been satisfactory in terms of wear resistance. Even when a reactive binder is used, the molecular weight of the cured product is increased, but the number of intermolecular crosslinks is small, and it is difficult to achieve a balance between the amount of the charge transporting substance and the crosslink density. Abrasion was not sufficient.

  In order to solve the above problems, it is known to provide as a protective layer a layer obtained by curing a radically polymerizable monomer having no charge transporting structure and a radically polymerizable compound having a charge transporting structure by light energy irradiation means. (For example, refer to Patent Document 6: Japanese Patent Application Laid-Open No. 2004-302451). Since this photoreceptor does not contain a binder resin in the protective layer, the three-dimensional network structure is sufficiently advanced, and the cross-linking density becomes very large, so that it is possible to exhibit a dramatic wear resistance. . Furthermore, since the electrotransport material is crosslinked, it is possible to achieve both wear resistance and electrical characteristics.

  However, it has been found that the ability of the crosslinked film to retain a positive charge is extremely reduced by repeating charging and exposure as compared with a film in which a charge transport material is dispersed in a normal binder resin. The cause has not been clarified yet, and it is assumed that the crosslinked film is deteriorated for some reason. When the photosensitive member having a cross-linked film is positively charged by the transfer bias described above, positive charges are injected into the photosensitive layer without being held on the surface. Most of the charge is trapped in the middle of the photosensitive layer and then moves to the surface when it is negatively charged to cancel the negative charge on the surface. As a result, the charged potential at that portion is lowered, resulting in a negative afterimage after exposure and an abnormal image. It has been found that the positive charge holding ability decreases in proportion to the number of times charging and exposure are repeated. In addition, it is considered that the degradation of the crosslinked film is not only the outermost surface of the surface layer but also the interior is gradually degraded, and when the interior is exposed due to wear, the internal crosslinked film is also considerably degraded and the afterimage is negative It gets worse.

JP 56-48637 A JP-A 64-1728 JP-A-4-281461 Japanese Patent No. 3262488 Japanese Patent No. 3194392 JP 2004-302451 A

  An object of the present invention is to solve the conventional problems and achieve the following objects. That is, according to the present invention, an image forming apparatus employing a roller type or belt type transfer unit in which a transfer unit applies a positive potential to a photoconductor to form a high-quality image at high speed. By changing the concentration of the compound having both hindered phenol structure and hindered amine structure in the surface layer on the surface and inside, high durability is maintained and abnormal images are generated when used repeatedly at high speed. It is another object of the present invention to provide an image type apparatus capable of outputting an image in a stable state and an image forming process cartridge.

As a result of intensive studies, the present inventors have found that the above problems can be solved by the following (1) to (15), and have accomplished the present invention.
(1) “In an image forming apparatus having an electrophotographic photosensitive member and at least an electrostatic latent image forming unit, a developing unit, a transferring unit, and a fixing unit on the photosensitive unit, the transfer unit applies a positive potential to the photosensitive unit. A roller-type or belt-type transfer means, wherein the electrophotographic photosensitive member has at least a photosensitive layer on a conductive support, at least a trifunctional or higher functional radical polymerizable monomer having no charge transporting structure, and a charge transporting property. A layer structure in which a surface layer obtained by curing a radically polymerizable compound having a structure by light energy irradiation means is sequentially laminated, and the surface layer contains a compound having both a hindered phenol structure and a hindered amine structure, The concentration of the compound having both the hindered phenol structure and the hindered amine structure is different between the surface and the interior. Forming apparatus ",
(2) The image according to item (1), wherein the concentration of a compound having both a hindered phenol structure and a hindered amine structure is larger in the interior than in the surface. Forming method ",
(3) “The image forming apparatus according to (1) or (2), wherein the radical polymerizable compound having a charge transporting structure is monofunctional”;
(4) “A trifunctional or higher functional radical monomer having no charge transporting structure is a trifunctional or higher functional radical having no charge transporting structure and having a functional group of an acryloyloxy group and / or a methacryloyloxy group. The image forming apparatus according to any one of (1) to (3), wherein the image forming apparatus is a polymerizable monomer,
(5) "The radically polymerizable compound having a charge transporting structure is a radically polymerizable compound having a charge transporting structure and having a functional group of an acryloyloxy group and / or a methacryloyloxy group. The image forming apparatus according to any one of (1) to (3),
(6) “A radical polymerizable compound having a charge transporting structure is a radical polymerizable compound having a triarylamine structure,” according to any one of (1) to (3), Described image forming apparatus ",
(7) “The radical polymerizable compound having a charge transporting structure is one or more radical polymerizable compounds represented by the following general formula (1) or (2): The image forming apparatus according to any one of 6);

（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）、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基、アルキレンオキシカルボニル基を表わす。ｍ、ｎは０〜３の整数を表わす。）」、
（８）「前記電荷輸送性構造を有するラジカル重合性化合物が、下記一般式（３）の一種以上のラジカル重合性化合物であることを特徴とする前記第（１）項乃至第（７）項のいずれかに記載の画像形成装置；

(In the formula, 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, Group, alkoxy group, —COOR ₇ (R ₇ is 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), halogen Carbonyl group or CONR ₈ R ₉ (R ₈ and R ₉ may 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. Ar ₁ and Ar ₂ each represent a substituted or unsubstituted arylene group, and may be the same or different.Ar ₃ , which may be the same or different from each other. Ar ₄ may be substituted Represents an unsubstituted aryl group, which 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 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 group, or an alkyleneoxycarbonyl group, and m and n represent an integer of 0 to 3.) "
(8) The items (1) to (7), wherein the radical polymerizable compound having the charge transport structure is one or more radical polymerizable compounds represented by the following general formula (3): An image forming apparatus according to any one of the above;

（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 represents an integer of 0 to 3. Za is a single bond, a methylene group, an ethylene group,

を表わす。）」、
（９）「感光層中に電荷発生物質としてチタニルフタロシアニンを含有することを特徴とする前記第（１）項乃至第（８）項のいずれかに記載の画像形成装置」、
（１０）「上記チタニルフタロシアニンがＣｕ−Ｋα線に対するＸ線回折スペクトルにおいてブラッグ角２θの主要ピークが少なくとも９．６°±０．２°、２４．０°±０．２°および２７．２°±０．２°にある結晶型を有するものであることを特徴とする前記第（９）項に記載の画像形成装置」、
（１１）「電子写真感光体と、感光体上に少なくとも静電潜像形成手段、現像手段、転写手段、定着手段を有する画像形成装置において、前記転写手段が感光体に対して正電位を印加するローラ方式もしくはベルト方式の転写手段であり、前記感光体が、導電性支持体上に少なくとも感光層と、少なくとも電荷輸送性構造を有しない３官能以上のラジカル重合性モノマーと電荷輸送性構造を有するラジカル重合性化合物を光エネルギー照射手段によって硬化させた表面層を順次積層した層構成を有し、前記表面層中にヒンダードフェノール構造とヒンダードアミン構造の両構造を有する化合物を含有し、前記ヒンダードフェノール構造とヒンダードアミン構造の両構造を有する化合物の濃度が表面と内部で異なる電子写真感光体であり、前記表面層はスプレー塗工法によって塗布されたものであることを特徴とする前記第（１）項乃至第（１０）項のいずれかに記載の画像形成装置」、
（１２）「前記表面層のスプレー塗布法が、スプレー塗布を複数回行ない、それぞれの塗布において、ヒンダードフェノール構造とヒンダードアミン構造の両構造を有する化合物の濃度が異なる塗布液を用いて塗布されるものであることを特徴とする前記第（１１）項に記載の画像形成装置」、
（１３）「前記電子写真感光体は、前記表面層のスプレー塗布をすべて終了した後、光エネルギー照射手段によって硬化させたものであることを特徴とする前記第（１１）項又は第（１２）項に記載の画像形成装置」、
（１４）「画像形成時における前記感光体の線速が３００ｍｍ／ｓｅｃ以上であることを特徴とする前記第（１）項乃至第（１３）項のいずれかに記載の画像形成装置」、
（１５）「電子写真感光体と、静電潜像形成手段、現像手段及びクリーニング手段から選択される１つ以上の手段とが一体となり、装置本体と着脱自在なプロセスカートリッジを搭載していることを特徴とする前記第（１）項乃至第（１４）項のいずれかに記載の画像形成装置」

Represents. ) ",
(9) "The image forming apparatus according to any one of (1) to (8) above, wherein the photosensitive layer contains titanyl phthalocyanine as a charge generating substance",
(10) “The titanyl phthalocyanine has a major peak at a Bragg angle 2θ of at least 9.6 ° ± 0.2 °, 24.0 ° ± 0.2 °, and 27.2 ° in an X-ray diffraction spectrum with respect to Cu—Kα ray. The image forming apparatus according to item (9), which has a crystal type of ± 0.2 °,
(11) In an image forming apparatus having an electrophotographic photosensitive member and at least an electrostatic latent image forming unit, a developing unit, a transferring unit, and a fixing unit on the photosensitive member, the transfer unit applies a positive potential to the photosensitive member. A roller-type or belt-type transfer means, wherein the photoconductor comprises at least a photosensitive layer on a conductive support, at least a trifunctional or higher-functional radical polymerizable monomer having no charge transport structure and a charge transport structure. Having a layer structure in which surface layers obtained by curing radically polymerizable compounds having light-irradiation means are sequentially laminated, the surface layer containing a compound having both a hindered phenol structure and a hindered amine structure, An electrophotographic photoreceptor in which the concentration of a compound having both a dophenol structure and a hindered amine structure is different between the surface and the inside, The surface layer may be equal to those applied by a spray coating method first (1) The image forming apparatus according to any one of claim to the (10) term "
(12) “The spray coating method of the surface layer performs spray coating a plurality of times, and each coating is performed using coating solutions having different concentrations of compounds having both a hindered phenol structure and a hindered amine structure. The image forming apparatus according to item (11),
(13) The item (11) or (12), wherein the electrophotographic photosensitive member is cured by light energy irradiation means after all the spray coating of the surface layer is completed. The image forming apparatus according to the item ",
(14) "The image forming apparatus according to any one of (1) to (13) above, wherein a linear velocity of the photosensitive member during image formation is 300 mm / sec or more",
(15) “The electrophotographic photosensitive member and at least one means selected from an electrostatic latent image forming means, a developing means, and a cleaning means are integrated, and a process cartridge that is detachable from the apparatus main body is mounted. The image forming apparatus according to any one of (1) to (14), characterized in that:

  According to the present invention, in an image forming apparatus having at least an electrostatic latent image forming unit, a developing unit, a transfer unit, and a fixing unit on a photoconductor, a roller system in which the transfer unit applies a positive potential to the photoconductor, Or a belt type transfer means, wherein the electrophotographic photosensitive member has at least a photosensitive layer on a conductive support, at least a trifunctional or higher functional radical polymerizable monomer having no charge transporting structure and a charge transporting structure. A surface structure in which a surface layer obtained by curing a radical polymerizable compound by light energy irradiation means is sequentially laminated, the surface layer containing a compound having both a hindered phenol structure and a hindered amine structure, High durability by changing the concentration of the compound having both hindered phenol structure and hindered amine structure inside and outside There, when used repeatedly at high speed, there is no occurrence of abnormal image, stable image forming apparatus can output a high resolution image and an image forming apparatus for the process cartridge can be provided.

  The image forming apparatus of the present invention includes at least a photosensitive member, an exposure unit, a developing unit, a transfer unit, and a fixing unit, and the transfer unit applies a positive potential to a roller type or belt type transfer unit, and the photosensitive unit The body was cured by light energy irradiation means at least a photosensitive layer, a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a charge transport structure on a conductive support. It is composed of a layer structure in which surface layers are sequentially laminated, and contains a compound having both a hindered phenol structure and a hindered amine structure in the surface layer, and has both structures of the hindered phenol structure and the hindered amine structure in the surface layer. By changing the concentration of the compound in the surface and inside, the transfer roller can be It is possible to suppress the negative residual image by the transfer roller or a transfer belt, is. More specifically, by increasing the concentration of the radical polymerizable compound having a charge transporting structure from the surface layer to the inside, the deterioration of the negative afterimage is remarkably suppressed in a system in which the surface layer gradually wears. I understood.

-Electrophotographic photoreceptor-
The electrophotographic photosensitive member is not particularly limited with respect to the material, shape, structure, size, etc., and can be appropriately selected from known ones. The support, and at least the charge generation layer and the charge on the support are included. A transport layer and a surface layer are laminated in this order, and at least a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a charge transport structure as a surface layer are irradiated with light energy. In this structure, the surface layers cured in order are laminated in sequence, and the concentration of the radical polymerizable compound having a charge transporting structure in the surface layer is different between the surface and the inside.

[Trifunctional or higher radical polymerizable monomer having no charge transport property]
The trifunctional or higher functional radical polymerizable monomer having no charge transport property used for the surface layer is a hole transport structure such as triarylamine, hydrazone, pyrazoline, carbazole, such as condensed polycyclic quinone, diphenoquinone, cyano. A monomer having no electron transport structure such as an electron-withdrawing aromatic ring having a group or a nitro group and having three or more radically polymerizable functional groups. The radical polymerizable functional group may be any group having a carbon-carbon double bond and capable of radical polymerization.

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、アクリロイルアミノ基、ビニルチオエーテル基等が挙げられる。

(In the formula, X ₁ is an arylene group such as a phenylene group or a naphthylene group which may have a substituent, an alkenylene group which may have 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 vinyl group, styryl group, 2-methyl-1,3-butadienyl group, vinylcarbonyl group, acryloyloxy group, acryloylamino group, vinylthioether group and the like.

(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、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は上記式１０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。）

(In the formula, Y is an aryl group such as an alkyl group which may have a substituent, an aralkyl group which may have a substituent, a phenyl group which may have a substituent, or a naphthyl group. 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 which may have a substituent, a phenethyl group or the like, an aryl group such as a phenyl group or a naphthyl group which may have a substituent, or -CONR ₁₂ R ₁₃ (R ₁₂ and R ₁₃ is a hydrogen atom, 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 Ara such phenethyl group, Kill group or substituent a phenyl group which may have a, an aryl group such as a naphthyl group, which may be the same or different from each other.) Further, X ₂ is the same as X ₁ in the formula 10 A substituent, a single bond, or an alkylene group, provided that at least one of Y and X ₂ is an oxycarbonyl group, 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 a compound having three or more acryloyloxy groups is, for example, a compound having three or more hydroxyl groups in the molecule and an acrylic group. 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 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 trifunctional or higher functional radical polymerizable monomer having no charge transporting 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, trimethylolpropane alkylene-modified triacrylate, trimethylolpropane ethyleneoxy-modified (hereinafter referred to as EO modification). ) Triacrylate, trimethylolpropane propyleneoxy modified (hereinafter PO modified) triacrylate, trimethylolpropane caprolactone modified triacrylate, trimethylolpropane alkylene modified trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol Triacrylate, glycerol epichlorohydrin modification (hereinafter ECH modification) Reacrylate, glycerol EO modified triacrylate, glycerol PO modified triacrylate, tris (acryloxyethyl) isocyanurate, dipentaerythritol hexaacrylate (DPHA), dipentaerythritol caprolactone modified hexaacrylate, dipentaerythritol hydroxypentaacrylate, Alkylated dipentaerythritol pentaacrylate, alkylated dipentaerythritol tetraacrylate, alkylated dipentaerythritol triacrylate, dimethylolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, phosphoric acid EO modified triacrylate, 2,2, 5,5, -tetrahydroxymethylcyclopentanone tetraacryl Such as over preparative and the like, which may be used in combination either alone or in combination.

  In addition, the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure used in the present invention has a functional group ratio (molecular weight / functional group number) of 250 in order to form a dense cross-linked bond in the cross-linked surface layer. The following is desirable. When the functional group ratio is larger than 250, the crosslinked surface layer is soft and wear resistance is somewhat lowered. Therefore, among monomers exemplified above, monomers having a modifying group such as EO, PO, caprolactone, etc. It is not preferable to use a compound having a long modifying group alone. In addition, the proportion of the trifunctional or higher functional radical polymerizable monomer having no charge transport structure used for the surface layer is 20 to 80% by weight, preferably 30 to 70% by weight, based on the total amount of the crosslinked surface layer. Specifically, it depends on the ratio of the tri- or higher functional radical polymerizable monomer in the solid content of the coating liquid. 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.

[Radically polymerizable compound having a charge transporting structure]
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 transport structure such as an electron-withdrawing aromatic ring and having a radical polymerizable functional group. Examples of the radical polymerizable functional group include those shown in the above radical polymerizable monomer, and acryloyloxy group and methacryloyloxy group are particularly useful.

  In addition, as the radical polymerizable compound having a charge transporting structure, a polyfunctional compound having two or more functional groups can be used, but a monofunctional compound is preferable in terms of film quality and electrostatic characteristics. This is because when a bifunctional or higher functional charge transport compound is used, it is fixed in the crosslinked structure by a plurality of bonds. However, since the charge transport structure is very bulky, distortion occurs in the cured resin, resulting in a crosslinked surface layer. The internal stress of the film becomes high, and peeling wear tends to occur.

  In addition, in terms of electrostatic characteristics, when a bifunctional or higher functional charge transporting compound is used, it is fixed in the crosslinked structure with a plurality of bonds, so that the intermediate structure (cation radical) during charge transport is stably maintained. In other words, the sensitivity is lowered due to charge trapping, and the residual potential is likely to increase. Such deterioration of the electrical characteristics appears as an image such as a decrease in image density and thinning of characters. For this reason, the radical polymerizable compound having a charge transporting structure uses a radical polymerizable compound having a monofunctional charge transporting structure and is fixed in a pendant shape between crosslinks, thereby causing cracks and scratches. And stabilization of electrostatic characteristics.

  Further, the triarylamine structure is highly effective as a charge transporting structure. In addition, those having one functional group are preferable, and when a compound represented by the structure of the following general formula (1) or (2) is used, electrical characteristics such as sensitivity and residual potential are favorably sustained. .

（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）、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。）

(In the formula, 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, Group, alkoxy group, —COOR ₇ (R ₇ is 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), halogen Carbonyl group or CONR ₈ R ₉ (R ₈ and R ₉ may 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. Ar ₁ and Ar ₂ each represent a substituted or unsubstituted arylene group, and may be the same or different.Ar ₃ , which may be the same or different from each other. Ar ₄ may be substituted Represents an unsubstituted aryl group, which 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 group, O represents 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, and m and n are integers of 0 to 3. Represents.)

Specific examples of general formulas (1) and (2) are shown below.
In the general formulas (1) and (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, and examples of the aryl group include a phenyl group and a naphthyl group. The aralkyl group includes a benzyl group, a phenethyl group, and a naphthylmethyl group, and the alkoxy group includes a methoxy group, an ethoxy group, a propoxy group, and the like. These include a halogen atom, a nitro group, a cyano group, and a methyl group. Substituted with an alkyl group such as an ethyl group, an alkoxy group such as a methoxy group or an ethoxy group, an aryloxy group such as a phenoxy group, an aryl group such as a phenyl group or a naphthyl group, an aralkyl group such as a benzyl group or a phenethyl group, etc. 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 a condensed polycyclic hydrocarbon group, a non-fused cyclic hydrocarbon group, and a heterocyclic group.
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, an as-indacenyl group. , S-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 , A chrycenyl group, a 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.

Further, 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) Alkyl groups, preferably C ₁ -C _12, especially C ₁ -C ₈ , more preferably C ₁ -C ₄ linear or branched alkyl groups, further including fluorine atoms , a hydroxyl group, a cyano _group, an alkoxy group of C 1 -C _4, a phenyl group or a halogen _atom, which may have a phenyl group substituted by an alkoxy group C 1 -C ₄ alkyl or _C 1 -C ₄ Good. 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 ), wherein 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) An aryloxy group, and 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) Alkyl mercapto group or aryl mercapto group, and specific examples include methylthio group, ethylthio group, phenylthio group, p-methylphenylthio group and the like.
(6)

（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等が挙げられる。
（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。

(Wherein 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.

The arylene group represented by Ar ₁ and Ar ₂ is a divalent group derived from the aryl group represented by Ar ₃ and 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.
The substituted or unsubstituted alkylene ether group represents ethyleneoxy, propyleneoxy, ethylene glycol, propylene glycol, diethylene glycol, tetraethylene glycol, tripropylene glycol, alkylene ether group alkylene group is hydroxyl group, methyl group, ethyl group, etc. You may have the substituent of.
The vinylene group is

で表わされ、

Represented by

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

Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether divalent group, or an alkyleneoxycarbonyl divalent group.
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 divalent group of the alkylene ether group of X.
Examples of the alkyleneoxycarbonyl divalent group include a caprolactone-modified divalent group.

  Further, the radical polymerizable compound having a monofunctional charge transport structure of the present invention is more preferably a compound having a 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 represents an integer of 0 to 3. Za is a single bond, a methylene group, an ethylene group,

を表わす。）

Represents. )

  As the compound represented by the above general formula, a compound having a methyl group or an ethyl group as a substituent for Rb and Rc is particularly preferable.

The radically polymerizable compound having a monofunctional charge transport structure represented by the general formulas (1) and (2), particularly (3) used in the present invention is polymerized with the carbon-carbon double bond open on both sides. Therefore, in a polymer that is not a terminal structure but is incorporated in a chain polymer and crosslinked by polymerization with a tri- or higher functional radical polymerizable monomer, it exists in the main chain of the polymer, and Present in the cross-linked chain between the chain and the main chain (this cross-linked chain has an intermolecular cross-linked chain between one polymer and another polymer, and a site where the main chain is folded in one polymer. And other intramolecular cross-linked chains that are cross-linked with other sites derived from the polymerized monomer at positions away from this in the main chain), but even if they are present in the main chain, Even if present, the triarylamine structure suspended from the chain moiety is It has at least three aryl groups arranged in the radial direction and is bulky, but is not directly bonded to the chain part, but is suspended from the chain part via a carbonyl group, etc. Since these triarylamine structures can be arranged adjacent to each other in the polymer, there is little structural distortion in the molecule, and the surface of the electrophotographic photosensitive member is also fixed. In the case of a layer, it is presumed that an intramolecular structure that is relatively free from interruption of the charge transport pathway can be adopted.
Specific examples of the radically polymerizable compound having a charge transporting structure of the present invention are shown below, but are not limited to the compounds having these structures.

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

  Specific examples of the radical polymerizable compound having a trifunctional charge transporting structure of the present invention are shown below in No. 364, but are not limited to compounds having these structures.

  The radical polymerizable compound having a charge transport structure used in the present invention is important for imparting the charge transport performance of the crosslinked surface layer, and this component is preferably 20 to 80% by weight, preferably based on the total amount of the crosslinked surface layer. Is 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, regarding the compound having both the hindered phenol structure and the hindered amine structure used in the present invention, the hindered amine structure refers to a structure in which a bulky atomic group exists in the vicinity of the amino nitrogen atom. So-called aromatic amines and aliphatic amines also fall under this category. The hindered phenol structure refers to a structure in which a bulky atomic group exists at the ortho position of the phenolic hydroxyl group. Although the details of the mechanism of action of the compounds having both of these structures have not been clarified, the steric hindrance caused by the presence of bulky atomic groups suppresses the thermal vibration of amino nitrogen atoms and phenolic hydroxyl groups, resulting in external activity. It is estimated that the effects of gas and the like are suppressed.

  There are various examples of compounds having both a hindered amine structure and a hindered phenol structure. In the present invention, these known compounds can be used, and among them, 1--represented by the following structural formula (I) [2- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl Oxy] -2,2,6,6-tetramethylpyridine is preferred.

  The addition concentration of the compound having both the hindered phenol structure and the hindered amine structure is suitably 0.5% or more and 5% or less with respect to the total solid content of the coating liquid. An afterimage suppression effect cannot be obtained, while if it exceeds 5%, the electrical characteristics such as an increase in residual potential are adversely affected.

The surface layer of the present invention changes the concentration distribution in the depth direction of the surface layer of the compound having both the hindered phenol structure and the hindered amine structure described above, thereby causing image degradation, particularly negative afterimage, in a system that wears the surface layer. It becomes possible to suppress. The cause of negative image retention is not clear, but it is thought that negative image retention is suppressed because the injection of positive charge by the transfer belt is suppressed by both the hindered phenol structure and the hindered amine structure. Yes. Specifically, by increasing the concentration in the surface layer depth direction of the compound having both the hindered phenol structure and the hindered amine structure toward the inside, the hindered phenol structure and the inside of the surface layer where electrostatic fatigue accumulates are obtained. The amount of precipitation of the compound having both structures of the hindered amine structure increases, and the negative afterimage suppressing effect is sustained.
The concentration ratio between the surface and the inside of the surface layer of the compound having both the hindered phenol structure and the hindered amine structure is preferably 1/99 to 50/50. When the concentration ratio between the surface and the inside of the surface layer of the compound having both the hindered phenol structure and the hindered amine structure is 1/99 or less, a negative afterimage is generated from the beginning. Moreover, in the case of 50/50 or more, the negative afterimage suppression effect after abrasion is very small.

  The surface layer of the present invention is obtained by curing at least a trifunctional or higher-functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a charge transport structure by light energy irradiation means. Monofunctional and bifunctional radically polymerizable monomers and radically polymerizable oligomers can be used in combination for the purpose of imparting functions such as viscosity adjustment during coating, stress relaxation of the cross-linked surface layer, lower surface energy and reduced friction coefficient. . Known radical polymerizable monomers and oligomers 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, neopentyl glycol diacrylate, and the like.

Examples of the functional monomer include those substituted with a fluorine atom such as octafluoropentyl acrylate, 2-perfluorooctylethyl acrylate, 2-perfluorooctylethyl methacrylate, 2-perfluoroisononylethyl acrylate, No. 60503, JP-B-6-45770, siloxane repeating units: 20-70 acryloyl polydimethylsiloxane ethyl, methacryloyl polydimethylsiloxane ethyl, acryloyl polydimethylsiloxane propyl, acryloyl polydimethylsiloxane butyl, diacryloyl polydimethylsiloxane Examples include vinyl monomers having a polysiloxane group such as diethyl, acrylates and methacrylates.
Examples of the radical polymerizable oligomer include epoxy acrylate, urethane acrylate, and polyester acrylate oligomers. However, when a large amount of monofunctional and bifunctional radically polymerizable monomers and radically polymerizable oligomers are contained, the three-dimensional cross-linking density of the cross-linked surface layer is substantially reduced, resulting in a decrease in wear resistance. For this reason, the content of these monomers and oligomers is limited to 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.
The surface layer of the present invention is obtained by curing at least a trifunctional or higher-functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. In order to advance the reaction efficiently, a polymerization initiator may be used.

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

  The crosslinked surface layer of the present invention has at least a trifunctional or higher-functional radical polymerizable monomer having no charge transport structure, a radical polymerizable compound having a monofunctional charge transport structure, and a hindered phenol structure and a hindered amine structure. It is formed by applying and curing a coating solution containing a compound. When the radically polymerizable monomer is a liquid, such a coating liquid can be applied by dissolving other components in the liquid, but is diluted with a solvent as required. Solvents used at this time include alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, tetrahydrofuran, dioxane and propyl ether. And ethers such as dichloromethane, dichloroethane, trichloroethane, and chlorobenzene, aromatics such as benzene, toluene, and xylene, and cellosolves such as methyl cellosolve, ethyl cellosolve, and cellosolve acetate. These solvents may be used alone or in combination of two or more. The dilution ratio with the solvent varies depending on the solubility of the composition, the coating method, and the target film thickness, and is arbitrary. The coating can be performed using a dip coating method, spray coating, bead coating, ring coating method, etc. Among them, the surface layer has a hindered phenol structure and a hindered amine structure of the inner layer already provided. A spray coating method that does not significantly interfere with the concentration of the compound having both structures is preferably used.

An example of a method for producing the electrophotographic photosensitive member of the present invention will be given. First, a plurality of cross-linked surface layers in which the concentration of a radical polymerizable compound having a charge transporting structure is changed on a photoreceptor in which an undercoat layer, a charge generation layer, and the above charge transport layer are sequentially laminated on a support such as an aluminum cylinder. The coating liquid is sequentially applied by spraying or the like, and then the crosslinked surface layer is cured by light energy irradiation means. After the curing is completed, the photosensitive member of the present invention is obtained by heating at 100 to 150 ° C. for 10 to 30 minutes to reduce the residual solvent.
Hereinafter, the present invention will be described according to the layer structure.

<About the layer structure of the electrophotographic photoreceptor>
The electrophotographic photosensitive member used in the present invention will be described with reference to the drawings.
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 (33) having a charge generating function and a charge transporting function is provided on a conductive support (31). This is a photoreceptor.
FIG. 2 shows a photoreceptor having a laminated structure in which a charge generation layer (35) having a charge generation function and a charge transport layer (37) having a charge transport material function are laminated on a conductive support (31). is there.

<About conductive support>
As the conductive support (31), a material having a volume resistance of 10 ¹⁰ Ω · cm or less, for example, a metal such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, oxidation Metal oxide such as indium by vapor deposition or sputtering, film or cylindrical plastic, paper coated, or aluminum, aluminum alloy, nickel, stainless steel, etc. After conversion, a tube subjected to surface treatment such as cutting, superfinishing or polishing can be used. In addition, an endless nickel belt and an endless stainless steel belt disclosed in JP-A-52-36016 can also be used as the conductive support (31).

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

<About photosensitive layer>
Next, the photosensitive layer (33) 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 has a laminated structure (consisting of a charge generation layer and a charge transport layer)>
(Charge generation layer)
The charge generation layer (35) 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 a carbazole skeleton, azo pigments having a triphenylamine skeleton, azo pigments having a diphenylamine skeleton, dibenzothiophene skeleton Azo pigments having fluorenone skeleton, azo pigments having oxadiazole skeleton, azo pigments having bis-stilbene skeleton, azo pigments having distyryl oxadiazole skeleton, azo pigments having 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. Of these, phthalocyanines are particularly useful, and in particular, titanyl phthalocyanine, of which at least a major peak at a Bragg angle 2θ in an X-ray diffraction spectrum for Cu-Kα rays is at least 9.6 ° ± 0.2 °, 24 Titanyl phthalocyanine having a crystal form of 0.0 ° ± 0.2 ° and 27.2 ° ± 0.2 ° is particularly effective as a sensitive material. These charge generation materials can be used alone or as a mixture of two or more.

  The binder resin used as necessary for the charge generation layer (35) is 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 63-285552, JP-A 05-19497, JP-A 05-70595, JP-A 10-73944, and the like. Illustrated.

The charge generation layer (35) may contain a low molecular charge transport material.
Low molecular charge transport materials that can be used in combination with the charge generation layer (35) include hole transport materials and electron transport materials.
Examples of the electron transporting material include chloroanil, bromanyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide and diphenoquinone derivatives. These electron transport materials can be used alone or as a mixture of two or more.

  Examples of the hole transporting material include the electron donating materials shown below and are used favorably. As hole transport materials, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triaryls Other known materials such as methane derivatives, 9-styrylanthracene derivatives, pyrazoline derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, bisstilbene derivatives, enamine derivatives, and the like can be given. These hole transport materials can be used alone or as a mixture of two or more.

Methods for forming the charge generation layer (35) can be broadly divided into a vacuum thin film preparation method and a casting method from a solution dispersion system.
As the former method, a vacuum deposition method, a glow discharge decomposition method, an ion plating method, a sputtering method, a reactive sputtering method, a CVD method, or the like is used, and the above-described inorganic materials and organic materials can be satisfactorily formed.
In addition, in order to provide a charge generation layer by the casting method described later, if necessary, the inorganic or organic charge generation material together with a binder resin, tetrahydrofuran, dioxane, dioxolane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, cyclohexane. Can be formed by dispersing with a ball mill, attritor, sand mill, bead mill, etc. using a solvent such as pentanone, anisole, xylene, methyl ethyl ketone, acetone, ethyl acetate, butyl acetate, etc. . Moreover, leveling agents, such as a dimethyl silicone oil and a methylphenyl silicone oil, can be added as needed. The application can be performed by dip coating, spray coating, bead coating, ring coating, or the like.
The thickness of the charge generation layer provided as described above is suitably about 0.01 to 5 μm, preferably 0.05 to 2 μm.

(About charge transport layer)
The charge transport layer (37) is a layer having a charge transport function. The charge transport layer is formed by dissolving or dispersing a charge transport material having a charge transport function and a binder resin in a suitable solvent, and applying and drying the solution on the charge generation layer (35). The coating solution for the adhesive layer containing the radical polymerizable composition and the binder resin and the coating solution for the crosslinked surface layer containing the radical polymerizable composition are applied and 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 (35) can be used. As described above, the use of the polymer charge transport material can reduce the solubility of the lower layer at the time of coating the surface layer, and is particularly useful.

Examples of the binder resin include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, Polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin And thermoplastic or thermosetting resins such as phenol resins and alkyd resins.
The amount of the charge transport material is appropriately 20 to 300 parts by 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 charge transport layer, the same solvent as that used for the charge generation layer can be used, but a solvent that dissolves the charge transport material and the binder resin well is suitable. These solvents may be used alone or in combination of two or more. The charge transport layer can be formed by the same coating method as that for the charge generation layer (35).

If necessary, a plasticizer and a leveling agent can be added.
As a plasticizer that can be used in combination with the charge transport layer, those used as plasticizers for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is 0 with respect to 100 parts by weight of the binder resin. About 30 parts by weight is appropriate.
Leveling agents that can be used in combination with the charge transport layer include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain. The amount used is a binder resin. About 0 to 1 part by weight is appropriate for 100 parts by weight.
The thickness of the charge transport layer is suitably about 5 to 40 μm, preferably about 10 to 30 μm.
In the case of a laminated structure, a coating liquid containing a radically polymerizable composition is applied onto the charge transport layer, dried as necessary, and then cured by light energy irradiation means to form a crosslinked surface layer. 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 unevenness of the film thickness, and when it is 20 μm or more, the electrical characteristics deteriorate.

<Single photosensitive layer>
The photosensitive layer (33) having a single layer structure is a layer having a charge generation function and a charge transport function at the same time, and the cross-linked surface layer having a charge transport structure of the present invention contains a charge generation material having a charge generation function. It is useful as a photosensitive layer having a single layer structure. As described in the above method for forming a charge generation layer, a charge generation material having a charge generation function, a charge transport material having a charge transport function and a binder resin are dissolved or dispersed in an appropriate solvent, and this is applied. It can be formed by 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 (35) and the charge transport layer (37). As the binder resin, in addition to the binder resin previously mentioned in the section of the charge transport layer (37), the binder resin mentioned in the charge generation layer (35) 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 film thickness of the photosensitive layer is suitably about 5 to 30 μm, preferably about 10 to 25 μm.

In the case of a single layer structure, a coating solution containing a radically polymerizable composition is applied onto the photosensitive layer, dried as necessary, and then cured by light energy irradiation means to form a crosslinked surface layer. 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 unevenness of the film thickness, and when it exceeds 20 μm, the electrical characteristics deteriorate.
The charge generating 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. 10 to 70 parts by weight of the transport material is preferably used.

<About the undercoat layer>
In the photoreceptor of the present invention, an undercoat layer can be provided between the conductive support (31) and the photosensitive layer. In general, the undercoat layer is mainly composed of a resin. However, considering that the photosensitive layer is coated with a solvent on these resins, the resin may be a resin having high solvent resistance with respect to a general organic solvent. desirable. Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. Further, a metal oxide fine powder pigment exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like may be added to the undercoat layer in order to prevent moire and reduce residual potential.

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

<Addition of antioxidant to each layer>
Further, in the present invention, in order to improve environmental resistance, in order to prevent a decrease in sensitivity and an increase in residual potential, oxidation is prevented in each layer such as a photosensitive layer, a charge generation layer, a charge transport layer, and an undercoat layer. An agent can be added.
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.

-Electrostatic latent image forming means-
The electrostatic latent image can be formed by uniformly charging the surface of the photoconductor and then exposing it. The electrostatic latent image means includes at least a charger that uniformly charges the surface of the photoconductor and an exposure device that exposes the surface of the photoconductor.
The charging device can be selected according to the purpose. Examples of the non-contact charging method include corotron and stocotron. On the other hand, examples of the contact charging method include a roller, a brush, a film, and a rubber blade. Further, there is a charging method using a proximity type non-contact charger.
The exposure can be performed by exposing the surface of the photoreceptor using an exposure device. Examples of the exposure device include various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system.
A light source such as a light emitting diode (LED), a semiconductor laser (LD), or electroluminescence (EL) can be used as the light source of the exposure device.

-Development means-
The development can be performed by developing the electrostatic latent image with toner to form a visible image. The developing means is not particularly limited as long as it can be developed using toner, and can be selected from known ones. For example, means for developing an electrostatic latent image formed on a photoreceptor include development methods such as a cascade development method, a spray (powder cloud) development method, a fur brush development method, and a magnetic brush development method.
The developing unit may be of a dry development type or a wet development type. For example, a developing unit having a stirrer that frictionally stirs and charges the toner and a rotatable magnet roller is preferable. Can be mentioned.
In the developing device, for example, the toner and the carrier are mixed and agitated, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state to form a magnetic brush. . A part of the toner constituting the magnetic brush formed on the surface of the magnet roller moves to the surface of the photoconductor by an electric attractive force. As a result, the electrostatic latent image is developed with the toner to form a visible image with the toner on the surface of the photoreceptor.
The toner can be used for both forward development and reverse development depending on the charging characteristics of the toner used. When toner having a polarity opposite to the charged polarity of the photoreceptor is used, forward development is used, and when toner of the same polarity is used, the electrostatic latent image is developed by reversal development.

-Transfer means-
The transfer means is a means for transferring the visible image to a recording medium, and can be transferred onto the intermediate recording medium by using a method for directly transferring the visible image from the surface of the photoreceptor to the recording medium and an intermediate recording medium. There is a method in which the visual image is secondarily transferred onto the recording medium after the visual image is primarily transferred. Either form can be used satisfactorily.
A suitable example of the transfer means is a transfer / conveying belt that can simultaneously convey the recording medium.
The transfer means preferably peels and charges the visible image formed on the photoconductor toward the recording medium. The transfer means is preferably a transfer roller or a transfer belt having a conveying process. As a transfer method, it is desirable to use a contact type using a transfer roller or a transfer belt. Note that the polarity applied to the transfer roller or transfer belt is usually positive for the transfer roller or transfer belt in consideration of the charging polarity of the photoreceptor, the charging polarity of the toner, and the negative / positive development. A charge is applied.

-Fixing means-
The fixing may be performed each time the visible image transferred to the recording medium is fixed using a fixing device, and the toner of each color is transferred to the recording medium, or the toner is stacked on the toner of each color. May be performed simultaneously at the same time.
There is no restriction | limiting in particular as said fixing device, Although it can select suitably according to the objective, A well-known heating-pressing means is suitable. Examples of the heating and pressing means include a combination of a heating roller and a pressure roller, and a combination of a heating roller, a pressure roller, and an endless belt.
The heating in the heating and pressing means is usually preferably 80 ° C to 200 ° C.
The neutralization means is not particularly limited and may be any appropriate neutralization neutralizer as long as it can apply a neutralization bias to the photosensitive member. For example, a neutralization lamp is preferable. .

Here, one embodiment of the image forming apparatus of the present invention will be described with reference to FIG.
In FIG. 3, the photoconductor (1) has at least a photosensitive layer provided on a support, on which a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a radical having a charge transport structure. It is a layer structure in which a surface layer obtained by curing a polymerizable compound by light energy irradiation means is sequentially laminated, and the concentration of the radical polymerizable compound having the charge transport structure is different between the surface and the inside.

As a means for charging the photoconductor (1) on average, a charging charger (3) is used. As the charging means, a corotron device, a scorotron device, a solid discharge element, a needle electrode device, a roller charging device, a conductive brush device, or the like is used, and a known method can be used.
In particular, the configuration of the present invention is effective when a charging unit such as a contact charging method or a non-contact proximity arrangement charging method is used in which the photosensitive composition is decomposed by proximity discharge from the charging unit. The contact charging method referred to here is a charging method in which a charging roller, a charging brush, a charging blade, or the like is in direct contact with the photosensitive member. On the other hand, the proximity charging method is, for example, a type in which the charging roller is arranged in a non-contact state so as to have a gap of 200 μm or less between the surface of the photoreceptor and the charging means. If this gap is too large, the charging tends to become unstable, and if it is too small, the surface of the charging member may be contaminated when toner remaining on the photoreceptor exists. is there. Accordingly, the gap is suitably 10 to 200 μm, preferably 10 to 100 μm.

  Next, the image exposure unit (5) is used to form an electrostatic latent image on the uniformly charged photoreceptor (1). As the light source, all luminescent materials such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL) can be used. Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range.

  Next, the developing unit (6) is used to visualize the electrostatic latent image formed on the photoreceptor (1). Development methods include a one-component development method using a dry toner, a two-component development method, and a wet development method using a wet toner. When the photosensitive member is positively (negatively) charged and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. A positive image can be obtained by developing this with negative (positive) toner (electrodetection fine particles), and a negative image can be obtained by developing with positive (negative) toner.

Next, the transfer belt (10) is used to transfer the toner image visualized on the photosensitive member onto the transfer member (9). In addition, a pre-transfer charger (7) may be used for better transfer. As the electrostatic transfer method, the charging means can be used.
Next, a separation claw (12) is used as means for separating the transfer body (9) from the photoreceptor (1). As other separation means, electrostatic adsorption induction separation, side end belt separation, tip grip conveyance, curvature separation, and the like are used.

  Next, a fur brush (14) and a cleaning blade (15) are used to clean the toner remaining on the photoreceptor after transfer. Further, a pre-cleaning charger (13) may be used in order to perform cleaning more efficiently. Other cleaning means include a web method, a magnet brush method, and the like, but each may be used alone or in combination.

Next, a neutralizing unit is used for the purpose of removing the latent image on the photoconductor as necessary. As the charge removal means, a charge removal lamp (2) and a charge removal charger are used, and the exposure light source and the charging means can be used respectively.
In addition, known processes can be used for reading, feeding, fixing, paper discharge and the like that are not close to the photoconductor.
As is apparent from the above description, the electrophotographic photosensitive member of the present invention is not only used in electrophotographic copying machines, but also in electrophotographic application fields such as laser beam printers, CRT printers, LED printers, liquid crystal printers, and laser plate making. Can also be used widely.

The present invention is an image forming method and an image forming apparatus using the electrophotographic photoreceptor according to the present invention for such image forming means.
This image forming means may be fixedly incorporated in a copying apparatus, facsimile, or printer, but may be incorporated in these apparatuses in the form of a process cartridge and detachable. An example of the process cartridge is shown in FIG.
The process cartridge for the image forming apparatus includes a photoreceptor (101), and in addition, a charging unit (102), a developing unit (104), a transfer unit (106), a cleaning unit (107), and a discharging unit (not shown). ), And an apparatus (part) that can be attached to and detached from the image forming apparatus main body.
Referring to the image forming process by the apparatus illustrated in FIG. 4, the photosensitive member (101) is rotated by the charging means (102) while being rotated in the direction of the arrow, and the exposure means (not shown) is exposed (103). An electrostatic latent image corresponding to the exposure image is formed on the surface, and the electrostatic latent image is developed with toner by the developing means (104). The toner development is applied to the transfer body (105) by the transfer means (106). Transcribed and printed out. Next, the surface of the photoconductor after the image transfer is cleaned by a cleaning unit (107), and further neutralized by a neutralizing unit (not shown), and the above operation is repeated again.
The present invention provides a process cartridge for an image forming apparatus having a photoreceptor having a smooth charge transporting surface cross-linked layer and at least one of charging, developing, transferring, cleaning, and neutralizing means.

<Synthesis example of compound having monofunctional charge transport structure>
The compound having a monofunctional charge transport 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.
Melting point: 64.0-66.0 ° C

(2) Triarylamino group-substituted acrylate compound (Exemplary Compound No. 54 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. 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. In this way, Exemplified Compound No. As a result, 80.73 g (yield = 84.8%) of 54 white crystals were obtained.
Melting point: 117.5-119.0 ° C

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to a following example. Note that “parts” used in the examples all represent parts by weight.

First, a specific synthesis example of a titanyl phthalocyanine pigment used in Examples will be described.
(Synthesis Example 1)
292 g of 1,3-diiminoisoindoline and 2000 ml of sulfolane are mixed, and 204 g of titanium tetrabutoxide is added dropwise under a nitrogen stream. After completion of the dropwise addition, the temperature was gradually raised to 180 ° C., and the reaction was carried out by stirring for 5 hours while maintaining the reaction temperature between 170 ° C. and 180 ° C. After completion of the reaction, the mixture was allowed to cool, and then the precipitate was filtered, washed with chloroform until the powder turned blue, then washed several times with methanol, further washed several times with hot water at 80 ° C., and dried. Crude titanyl phthalocyanine was obtained. Dissolve the crude titanyl phthalocyanine in 20 times the amount of concentrated sulfuric acid, add dropwise to 100 times the amount of ice water with stirring, filter the precipitated crystals, and then repeat washing with water until the washing solution becomes neutral. Got. This wet cake was thoroughly washed with ion-exchanged water until sulfate ions could not be detected from the washing solution.
20 g of the obtained wet cake was put into 200 g of 1,2-dichloroethane and stirred for 4 hours. After adding 1000 g of methanol to this and stirring for 1 hour, it filtered and dried and obtained the titanyl phthalocyanine powder (this is called the pigment 1).
The X-ray diffraction spectrum of the obtained titanyl phthalocyanine pigment was measured under the following conditions.
X-ray tube: Cu
Voltage: 40 kV
Current: 20 mA
Scanning speed: 1 ° / min Scanning range: 3 ° -40 °
Time constant: 2 seconds

  An X-ray diffraction spectrum of the titanyl phthalocyanine pigment obtained in Synthesis Example 1 is shown in FIG. The resulting titanyl phthalocyanine pigment has a crystalline form with a major peak at a Bragg angle 2θ of at least 9.6 ° ± 0.2 °, 24.0 ° ± 0.2 ° and 27.2 ° ± 0.2 °. You can see that

[Example 1]
By coating and drying an undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution in the following order on a φ100 mm aluminum cylinder in sequence, an undercoat layer of 3.5 μm A 0.3 μm charge generation layer and a 23 μm charge transport layer were formed. On this charge transport layer, the coating solution A for crosslinked surface layer and the coating solution B for crosslinked surface layer having the following composition were sprayed successively, metal halide lamp: 160 W / cm, irradiation distance: 120 mm, irradiation intensity: 500 mW. / Cm ² , irradiation time: light irradiation under the conditions of 240 seconds, further drying at 130 ° C. for 20 minutes, cross-linking film 2 μm with cross-linking surface layer coating liquid A, cross-linking with cross-linking surface layer coating liquid B A surface cross-linked layer having a total film thickness of 4 μm and a film thickness of 2 μm was provided to obtain the electrophotographic photosensitive member of the present invention.
[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]
Titanyl phthalocyanine powder synthesized in Synthesis Example 1 4 parts Polyvinyl butyral 2 parts (S-REC BM-S, Sekisui Chemical Co., Ltd.)
150 parts of methyl ethyl ketone [coating liquid for charge transport layer]
10 parts of bisphenol Z-type polycarbonate (Panlite TS-2050, manufactured by Teijin Chemicals)
Low molecular charge transport material (D-1) of the following structural formula (II) 7 parts Tetrahydrofuran 100 parts 1% silicone oil tetrahydrofuran solution 1 part (KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

[Coating liquid A for cross-linked surface layer; for internal coating part]
Trifunctional or higher-functional radical polymerizable monomer having no charge transporting structure 10 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, Nippon Kayaku)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 54)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
SANOR LS2626 (manufactured by Sankyo Corporation) 1 part (Sanol LS2626 is a compound having both a hindered amine structure and a hindered phenol structure of the following structural formula (I))

テトラヒドロフラン １００部

Tetrahydrofuran 100 parts

[Crosslinking surface layer coating solution B; surface partial coating]
Trifunctional or higher-functional radical polymerizable monomer having no charge transporting structure 10 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, Nippon Kayaku)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 54)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
SANOR LS2626 (manufactured by Sankyo Corporation) 0.01 part Tetrahydrofuran 100 parts

[Example 2]
In Example 1, it produced similarly to Example 1 except having changed into the coating liquid for bridge | crosslinking surface layers of the following composition.

[Coating liquid A for cross-linked surface layer]
Trifunctional or higher-functional radical polymerizable monomer having no charge transporting structure 10 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, Nippon Kayaku)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 54)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
SANOL LS2626 (manufactured by Sankyo Corporation) 1 part Tetrahydrofuran 100 parts

[Coating liquid B for cross-linked surface layer]
Trifunctional or higher-functional radical polymerizable monomer having no charge transporting structure 10 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, Nippon Kayaku)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 54)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
SANOL LS2626 (manufactured by Sankyo Corporation) 0.05 parts Tetrahydrofuran 100 parts

[Example 3]
In Example 1, it produced similarly to Example 1 except having changed into the coating liquid for bridge | crosslinking surface layers of the following composition.
[Coating liquid A for cross-linked surface layer]
Trifunctional or higher-functional radical polymerizable monomer having no charge transporting structure 10 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, Nippon Kayaku)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 54)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
SANOL LS2626 (manufactured by Sankyo Corporation) 1 part Tetrahydrofuran 100 parts

[Coating liquid B for cross-linked surface layer]
Trifunctional or higher-functional radical polymerizable monomer having no charge transporting structure 10 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, Nippon Kayaku)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 54)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
SANOL LS2626 (manufactured by Sankyo Corporation) 0.1 part Tetrahydrofuran 100 parts

[Example 4]
In Example 1, it produced similarly to Example 1 except having changed into the coating liquid for bridge | crosslinking surface layers of the following composition.
[Coating liquid A for cross-linked surface layer]
Trifunctional or higher-functional radical polymerizable monomer having no charge transporting structure 10 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, Nippon Kayaku)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 54)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
SANOL LS2626 (manufactured by Sankyo Corporation) 1 part Tetrahydrofuran 100 parts

[Coating liquid B for cross-linked surface layer]
Trifunctional or higher-functional radical polymerizable monomer having no charge transporting structure 10 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, Nippon Kayaku)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 54)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
SANOL LS2626 (manufactured by Sankyo Corporation) 0.2 part Tetrahydrofuran 100 parts

[Comparative Example 1]
In Example 1, it replaced with the coating liquid A for bridge | crosslinking surface layers and the coating liquid B for bridge | crosslinking surface layers, and it was the same as that of Example 1 except having spray-coated only the coating liquid C for bridge | crosslinking surface layers of the following composition. Produced. The surface layer thickness is 4 μm.
[Crosslinking surface layer coating liquid C]
Trifunctional or higher-functional radical polymerizable monomer having no charge transporting structure 10 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, Nippon Kayaku)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 54)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
SANOL LS2626 (manufactured by Sankyo Corporation) 0.1 part Tetrahydrofuran 100 parts

(Real machine paper test)
500,000 sheets of the electrophotographic photosensitive members of Examples 1 to 4 and Comparative Example 1 manufactured as described above were used using a Ricoh imago Neo Neo 751 remodeling machine (photosensitive linear velocity (process linear velocity) was 350 mm / sec). (A4, MyPaper manufactured by NBS Ricoh Co., Ltd., charging potential at start-800V) was conducted, and wear characteristics, in-machine potential, and image evaluation were performed. The wear characteristics were determined by measuring the film thickness of the electrophotographic photoreceptor. The film thickness measuring device used was an eddy current film thickness meter (FISHERSCOPE). The dark portion potential of the in-machine potential was obtained from the surface potential when a white solid image was output with the grid voltage fixed at -900 (V). The surface potential was measured using TREK MODEL 344. The exposed portion potential was obtained from the surface potential when a black solid image was output by adjusting the grid potential so that the dark portion potential would be −800 (V). The image characteristics were evaluated by evaluating the degree of negative afterimage (see FIG. 7) that appears after the output of the original of FIG. Table 6 shows the wear characteristic results, Table 7 shows the in-machine voltage measurement results, and Table 8 shows the image characteristics (negative afterimage evaluation) results.

単位：μｍ

Unit: μm

単位：−Ｖ

Unit: -V

ネガ残像：○→なし、△→わずかに発生、×→はっきり発生

Negative afterimage: ○ → None, △ → Slightly generated, × → Clearly generated

[Example 5]
By coating and drying an undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution in the following order on a φ100 mm aluminum cylinder in order, an undercoat layer of 1.0 μm A 0.3 μm charge generation layer and a 23 μm charge transport layer were formed. On this charge transport layer, an adhesive layer coating solution and a crosslinked surface layer coating solution having the following composition were spray-coated successively, a metal halide lamp: 160 W / cm, an irradiation distance: 120 mm, an irradiation intensity: 500 mW / cm ^2. , Irradiation time: Light irradiation under conditions of 240 seconds, further drying at 130 ° C. for 20 minutes, cross-linked film 1.4 μm by cross-linked surface layer coating liquid D, cross-linked film by cross-linked surface layer coating liquid E A surface cross-linked layer having a total film thickness of 4.2 μm and a cross-linked film of 1.4 μm and a cross-linked film of the cross-linked surface layer coating solution F was provided to obtain an electrophotographic photoreceptor of the present invention.

[Undercoat layer coating solution]
Titanium oxide 40 parts Alcohol-soluble nylon 32 parts Methanol 400 parts Isopropanol 160 parts

[Charge generation layer coating solution]
Titanyl phthalocyanine powder synthesized in Synthesis Example 1 4 parts Polyvinyl butyral 2 parts (S-REC BM-S, Sekisui Chemical Co., Ltd.)
150 parts of methyl ethyl ketone

[Coating liquid for charge transport layer]
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
Low molecular charge transport material (D-1) of the following structural formula (II) 7 parts Tetrahydrofuran 100 parts 1% silicone oil tetrahydrofuran solution 1 part (KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

[Coating liquid D for cross-linked surface layer]
Trifunctional or higher radical polymerizable monomer having no charge transport structure 10 parts Dipentaerythritol hexaacrylate (KAYARAD DPHA, Nippon Kayaku)
Molecular weight: 536, number of functional groups: 5.5 functional, molecular weight / number of functional groups = 97
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 105)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Sanol LS2626 (Sankyo Co., Ltd.) 3 parts Tetrahydrofuran 100 parts

[Coating fluid E for cross-linked surface layer]
Trifunctional or higher radical polymerizable monomer having no charge transport structure 10 parts Dipentaerythritol hexaacrylate (KAYARAD DPHA, Nippon Kayaku)
Molecular weight: 536, number of functional groups: 5.5 functional, molecular weight / number of functional groups = 97
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 105)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
SANOR LS2626 (Sankyo Corporation) 1 part Tetrahydrofuran 100 parts

[Coating fluid F for cross-linked surface layer]
Trifunctional or higher radical polymerizable monomer having no charge transport structure 10 parts Dipentaerythritol hexaacrylate (KAYARAD DPHA, Nippon Kayaku)
Molecular weight: 536, number of functional groups: 5.5 functional, molecular weight / number of functional groups = 97
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 105)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
SANOL LS2626 (Sankyo Co., Ltd.) 0.01 part Tetrahydrofuran 100 parts

[Example 6]
In Example 5, it produced similarly to Example 5 except having changed into the coating liquid for bridge | crosslinking surface layers of the following composition.
[Coating liquid D for cross-linked surface layer]
Trifunctional or higher radical polymerizable monomer having no charge transport structure 10 parts Dipentaerythritol hexaacrylate (KAYARAD DPHA, Nippon Kayaku)
Molecular weight: 536, number of functional groups: 5.5 functional, molecular weight / number of functional groups = 97
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 105)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Sanol LS2626 (Sankyo Co., Ltd.) 3 parts Tetrahydrofuran 100 parts

[Coating fluid E for cross-linked surface layer]
Trifunctional or higher radical polymerizable monomer having no charge transport structure 10 parts Dipentaerythritol hexaacrylate (KAYARAD DPHA, Nippon Kayaku)
Molecular weight: 536, number of functional groups: 5.5 functional, molecular weight / number of functional groups = 97
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 105)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
SANOR LS2626 (Sankyo Corporation) 1 part Tetrahydrofuran 100 parts

[Coating fluid F for cross-linked surface layer]
Trifunctional or higher radical polymerizable monomer having no charge transport structure 10 parts Dipentaerythritol hexaacrylate (KAYARAD DPHA, Nippon Kayaku)
Molecular weight: 536, number of functional groups: 5.5 functional, molecular weight / number of functional groups = 97
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 105)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
SANOL LS2626 (Sankyo Corporation) 0.03 parts Tetrahydrofuran 100 parts

[Example 7]
In Example 5, it produced similarly to Example 5 except having changed into the coating liquid for bridge | crosslinking surface layers of the following composition.
[Coating liquid D for cross-linked surface layer]
Trifunctional or higher radical polymerizable monomer having no charge transport structure 10 parts Dipentaerythritol hexaacrylate (KAYARAD DPHA, Nippon Kayaku)
Molecular weight: 536, number of functional groups: 5.5 functional, molecular weight / number of functional groups = 97
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 105)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Sanol LS2626 (Sankyo Co., Ltd.) 3 parts Tetrahydrofuran 100 parts

[Coating fluid E for cross-linked surface layer]
Trifunctional or higher radical polymerizable monomer having no charge transport structure 10 parts Dipentaerythritol hexaacrylate (KAYARAD DPHA, Nippon Kayaku)
Molecular weight: 536, number of functional groups: 5.5 functional, molecular weight / number of functional groups = 97
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 105)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
SANOR LS2626 (Sankyo Corporation) 1 part Tetrahydrofuran 100 parts

[Coating fluid F for cross-linked surface layer]
Trifunctional or higher radical polymerizable monomer having no charge transport structure 10 parts Dipentaerythritol hexaacrylate (KAYARAD DPHA, Nippon Kayaku)
Molecular weight: 536, number of functional groups: 5.5 functional, molecular weight / number of functional groups = 97
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 105)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
SANOL LS2626 (Sankyo Co., Ltd.) 0.05 parts Tetrahydrofuran 100 parts

[Example 8]
In Example 5, it produced similarly to Example 5 except having changed into the coating liquid for bridge | crosslinking surface layers of the following composition.
[Coating liquid D for cross-linked surface layer]
Trifunctional or higher radical polymerizable monomer having no charge transport structure 10 parts Dipentaerythritol hexaacrylate (KAYARAD DPHA, Nippon Kayaku)
Molecular weight: 536, number of functional groups: 5.5 functional, molecular weight / number of functional groups = 97
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 105)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Sanol LS2626 (Sankyo Co., Ltd.) 3 parts Tetrahydrofuran 100 parts

[Coating fluid E for cross-linked surface layer]
Trifunctional or higher radical polymerizable monomer having no charge transport structure 10 parts Dipentaerythritol hexaacrylate (KAYARAD DPHA, Nippon Kayaku)
Molecular weight: 536, number of functional groups: 5.5 functional, molecular weight / number of functional groups = 97
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 105)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
SANOR LS2626 (Sankyo Corporation) 1 part Tetrahydrofuran 100 parts

[Coating fluid F for cross-linked surface layer]
Trifunctional or higher radical polymerizable monomer having no charge transport structure 10 parts Dipentaerythritol hexaacrylate (KAYARAD DPHA, Nippon Kayaku)
Molecular weight: 536, number of functional groups: 5.5 functional, molecular weight / number of functional groups = 97
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 105)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
SANOL LS2626 (Sankyo Co., Ltd.) 0.1 part Tetrahydrofuran 100 parts

[Comparative Example 2]
In Example 5, instead of the crosslinked surface layer coating solution D, the crosslinked surface layer coating solution E, and the crosslinked surface layer coating solution F, only the crosslinked surface layer coating solution G having the following composition was spray coated. The same procedure as in Example 5 was performed except that. The surface layer thickness is 4.2 μm.
[Coating liquid G for cross-linked surface layer]
Trifunctional or higher radical polymerizable monomer having no charge transport structure 10 parts Dipentaerythritol hexaacrylate (KAYARAD DPHA, Nippon Kayaku)
Molecular weight: 536, number of functional groups: 5.5 functional, molecular weight / number of functional groups = 97
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 105)
Photoinitiator 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
SANOL LS2626 (Sankyo Co., Ltd.) 0.01 part Tetrahydrofuran 100 parts

(Real machine paper test)
One million sheets of the electrophotographic photosensitive members of Examples 5 to 8 and Comparative Example 2 manufactured as described above using a Ricoh imago Neo Neo 1050 Pro modified machine (photosensitive linear velocity (process linear velocity) is 500 mm / sec). (A4, MyPaper manufactured by NBS Ricoh Co., Ltd., charging potential at start-800V) was conducted, and wear characteristics, in-machine potential, and image evaluation were performed. The wear characteristics were determined by measuring the film thickness of the electrophotographic photoreceptor. The film thickness measuring device used was an eddy current film thickness meter (FISHERSCOPE). The dark portion potential of the in-machine potential was obtained from the surface potential when a white solid image was output with the grid voltage fixed at -900 (V). The surface potential was measured using TREK MODEL 344. The exposed portion potential was obtained from the surface potential when a black solid image was output by adjusting the grid potential so that the dark portion potential would be −800 (V). The image characteristics were evaluated by evaluating the degree of negative afterimage (see FIG. 7) that appears after the output of the original of FIG. Table 9 shows the results of wear characteristics, Table 10 shows the results of in-machine voltage measurement, and Table 11 shows the results of image characteristics (negative afterimage evaluation).

単位：μｍ

Unit: μm

単位：−Ｖ

Unit: -V

ネガ残像：○→なし、△→わずかに発生、×→はっきり発生

Negative afterimage: ○ → None, △ → Slightly generated, × → Clearly generated

1 is an example of a cross-sectional view of an electrophotographic photosensitive member of the present invention. 1 is an example of a cross-sectional view of an electrophotographic photosensitive member of the present invention. 1 is a schematic diagram illustrating an example of an image forming apparatus of the present invention. FIG. 2 is a schematic diagram illustrating an example of a process cartridge for an image forming apparatus according to the present invention. 2 is an X-ray diffraction spectrum of the titanyl phthalocyanine pigment of the present invention. This is a manuscript used for image evaluation. This is a negative afterimage generated in a halftone image.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Static elimination lamp 3 Charger 4 Eraser 5 Image exposure part 6 Developing unit 7 Pre-transfer charger 8 Registration roller 9 Transfer paper 10 Transfer charger 12 Separation claw 13 Pre-cleaning charger 14 Fur brush 15 Cleaning blade 31 Conductive support 33 Photosensitive layer 35 Charge generation layer 37 Charge transport layer 101 Photosensitive drum 102 Charging device 103 Exposure device 104 Development device 105 Transfer body 106 Transfer device 107 Cleaning blade

Claims (15)

  In an image forming apparatus having an electrophotographic photosensitive member and at least an electrostatic latent image forming unit, a developing unit, a transferring unit, and a fixing unit on the photosensitive member, a roller system in which the transferring unit applies a positive potential to the photosensitive member or A belt type transfer means, wherein the electrophotographic photosensitive member has at least a photosensitive layer on a conductive support, at least a trifunctional or higher functional radical polymerizable monomer having no charge transporting structure, and a radical having a charge transporting structure. A layer structure in which a surface layer obtained by curing a polymerizable compound by light energy irradiation means is sequentially laminated, the surface layer containing a compound having both a hindered phenol structure and a hindered amine structure, and the hindered phenol An image forming apparatus characterized in that the concentration of a compound having both a structure and a hindered amine structure is different between the surface and the inside. .   The image forming method according to claim 1, wherein the concentration of the compound having both a hindered phenol structure and a hindered amine structure in the surface layer is larger in the interior than in the surface.   The image forming apparatus according to claim 1, wherein the radical polymerizable compound having the charge transporting structure is monofunctional.   The trifunctional or higher functional radical polymerizable monomer not having the charge transporting structure is a trifunctional or higher functional radical polymerizable monomer having no charge transporting structure and having a functional group of acryloyloxy group and / or methacryloyloxy group. The image forming apparatus according to claim 1, wherein the image forming apparatus is provided.   The radical polymerizable compound having a charge transporting structure is a radical polymerizable compound having a charge transporting structure and having a functional group of an acryloyloxy group and / or a methacryloyloxy group. The image forming apparatus according to claim 3. 4. The image forming apparatus according to claim 1, wherein the radical polymerizable compound having a charge transporting structure is a radical polymerizable compound having a triarylamine structure. 7. The image formation according to claim 1, wherein the radical polymerizable compound having a charge transporting structure is one or more radical polymerizable compounds represented by the following general formula (1) or (2). apparatus.

(In the formula, 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, Group, alkoxy group, —COOR ₇ (R ₇ is 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), halogen Carbonyl group or CONR ₈ R ₉ (R ₈ and R ₉ may 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. Ar ₁ and Ar ₂ each represent a substituted or unsubstituted arylene group, and may be the same or different.Ar ₃ , which may be the same or different from each other. Ar ₄ may be substituted Represents an unsubstituted aryl group, which 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 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 group, or an alkyleneoxycarbonyl group, and m and n represent an integer of 0 to 3.) 8. The image forming apparatus according to claim 1, wherein the radical polymerizable compound having a charge transporting structure is one or more radical polymerizable compounds represented by the following general formula (3).

(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 represents an integer of 0 to 3. Za is a single bond, a methylene group, an ethylene group,

Represents. )   9. The image forming apparatus according to claim 1, wherein the photosensitive layer contains titanyl phthalocyanine as a charge generating substance.   In the X-ray diffraction spectrum of the titanyl phthalocyanine with respect to the Cu-Kα ray, the main peaks with a Bragg angle 2θ are at least 9.6 ° ± 0.2 °, 24.0 ° ± 0.2 °, and 27.2 ° ± 0.2. The image forming apparatus according to claim 9, wherein the image forming apparatus has a crystal type at a temperature.   In an image forming apparatus having an electrophotographic photosensitive member and at least an electrostatic latent image forming unit, a developing unit, a transferring unit, and a fixing unit on the photosensitive member, a roller system in which the transferring unit applies a positive potential to the photosensitive member or A belt-type transfer means, wherein the photosensitive member has at least a photosensitive layer on a conductive support, at least a trifunctional or higher-functional radical polymerizable monomer having no charge transporting structure, and a radical polymerizable property having a charge transporting structure; It has a layer structure in which a surface layer obtained by curing a compound by light energy irradiation means is sequentially laminated, and the surface layer contains a compound having both a hindered phenol structure and a hindered amine structure, and the hindered phenol structure An electrophotographic photosensitive member in which the concentration of a compound having both structures of a hindered amine structure is different between the surface and the inside, and the surface layer is a The image forming apparatus according to any one of claims 1 to 10, characterized in that which is applied by laser coating method.   The spray coating method of the surface layer is performed by performing spray coating a plurality of times, and each coating is performed using coating solutions having different concentrations of compounds having both a hindered phenol structure and a hindered amine structure. The image forming apparatus according to claim 11.   13. The image forming apparatus according to claim 11, wherein the electrophotographic photosensitive member is cured by light energy irradiation means after all the spray coating of the surface layer is completed.   The image forming apparatus according to claim 1, wherein a linear velocity of the photoconductor during image formation is 300 mm / sec or more. The electrophotographic photosensitive member is integrated with at least one means selected from an electrostatic latent image forming means, a developing means, and a cleaning means, and is mounted with a process cartridge that is detachable from the apparatus main body. The image forming apparatus according to claim 1.

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