JP2009222977A - Electrophotographic photoreceptor, and process cartridge and electrophotographic device, having electrophotographic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor that hardly causes problems about electric characteristics and base contamination, and to provide a process cartridge and an electrophotographic device, having the electrophotographic photoreceptor. <P>SOLUTION: The electrophotographic photoreceptor includes a conductive support, an undercoat layer provided on the conductive support, and a photosensitive layer formed on the undercoat layer, wherein the undercoat layer contains a compound having at least a hydroxyl group and a straight-chain alkyl skeleton, a crosslinking resin and hydrophilic fine particles. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member, a process cartridge having an electrophotographic photosensitive member, and an electrophotographic apparatus.

  As an electrophotographic photosensitive member, a photosensitive layer (organic photosensitive layer) using an organic material as a photoconductive substance (a charge generating substance or a charge transporting substance) is provided on a cylindrical support due to advantages such as low cost and high productivity. An electrophotographic photosensitive member, so-called organic electrophotographic photosensitive member, is widely used. As an organic electrophotographic photosensitive member, due to advantages such as high sensitivity and high durability, a charge generating layer containing a charge generating substance such as a photoconductive dye or a photoconductive pigment, a photoconductive polymer or a photoconductive low molecule An electrophotographic photoreceptor having a photosensitive layer formed by laminating a charge transporting layer containing a charge transporting substance such as a compound, that is, a so-called laminated type photosensitive layer, is mainly used.

On the peripheral surface (surface) of the electrophotographic photosensitive member, electrical external forces such as charging (primary charging), exposure (image exposure), development with toner, transfer to a transfer material such as paper, cleaning of residual toner, etc. Or mechanical external force is applied directly. For this reason, the electrophotographic photosensitive member is required to have high image quality free from sensitivity, electrical characteristics, optical characteristics, mechanical characteristics, and image defects according to the applied electrophotographic process.

Typical image defects include image streaks, black spots on white portions, white spots on black portions, ground stains on white portions, and the like. Furthermore, when exposure is performed using a laser diode such as a digital copying machine or a laser beam printer as a light source, there are interference fringes generated due to factors such as the surface shape of the support and the film thickness unevenness of the electrophotographic photosensitive member.

As a method for preventing the image defects, an undercoat layer (a layer located in the lowermost layer of the electrophotographic photosensitive member, in other words, a layer between the conductive support and the charge generation layer) is used as necessary. It is done. The undercoat layer is required to have an electrical blocking function so that charge injection does not occur from the support when a voltage is applied to the electrophotographic photosensitive member. If there is charge injection from the support, the chargeability, image contrast, and reversal development method cause black spots on the white background and background stains, and the image quality is significantly reduced.

  On the other hand, if the electrical resistance of the undercoat layer is too high, the charge generated in the photosensitive layer stays inside the photosensitive layer, resulting in an increase in residual potential and potential fluctuation due to repeated use. Therefore, in addition to the electrical blocking function, it is necessary to reduce the electrical resistance value of the undercoat layer to some extent, and the blocking function and electrical characteristics should not change significantly.

As a technique for suppressing the occurrence of soiling on an organic electrophotographic photoreceptor, for example, Patent Document 1 discloses a cured layer using a metal alkoxide, aminoalkylsilane, aminoalkoxysilane, or aminoalkylalkoxysilane as an additive. An electrophotographic photoreceptor having a hole blocking layer or an undercoat layer is disclosed.
Patent Document 2 discloses an electrophotographic photosensitive member in which a cured layer using polyhaloalkylstyrene as an additive is a hole blocking layer.
In Patent Document 3 and Patent Document 4, a polymer compound having an alkoxysilyl group, the polymer compound and an organometallic compound, or the polymer compound, an organometallic compound, and a silane coupling agent are combined with heat energy. An electrophotographic photoreceptor using a cured layer formed by curing polymerization as an undercoat layer is disclosed.
Patent Documents 5 and 6 disclose electrophotographic photoreceptors in which a hardened layer using polyalkylene glycol or a derivative thereof as an additive is an undercoat layer.
Patent Document 7, Patent Document 8, and Patent Document 9 describe curing formed by curing and polymerizing an inorganic oxide network-forming compound, a metal atom-containing organic network-forming compound, and a binder network-forming compound with heat energy. An electrophotographic photoreceptor having a layer as an undercoat layer is disclosed.
Further, Patent Document 10 discloses a technique for enhancing the effect of suppressing the occurrence of background contamination of an electrophotographic photosensitive member by including an ionic liquid in the undercoat layer.
As an undercoat layer having an electrical blocking function and an appropriate range of electrical characteristics, for example, as an undercoat layer made of an organic polymer, Patent Document 11 and Patent Document 12, and metal oxides and metal nitrides are organic. Patent Document 13 and Patent Document 14 have been proposed as the undercoat layer dispersed in the polymer.
Further, as an undercoat layer for improving the carrier injection property from the photosensitive layer to the conductive support, for example, Patent Documents 15 to 19 describe that the undercoat layer contains an electron transport material.
Furthermore, as a technique for suppressing the occurrence of background stains, black spots, etc., for example, in Patent Document 20, a hardened layer using an organometallic compound, a coupling agent or a reaction product thereof as an additive is used as an undercoat layer. An electrophotographic photoreceptor is disclosed.

  As described above, in recent years, as a technique for suppressing the occurrence of scumming on an organic electrophotographic photoreceptor, an organic electrophotographic photoreceptor is provided by providing an undercoat layer with an electrical blocking function and an appropriate range of electrical characteristics. Technology has been established to increase the effect of suppressing the occurrence of soil contamination.

  However, the development of today's electrophotographic technology is remarkable, and very advanced technology is required for the characteristics required for electrophotographic photoreceptors. For example, process speeds are increasing year by year, and charging characteristics, sensitivity, durability stability, and the like have been demanded. In particular, in recent years, high-quality images have been screamed as typified by colorization, and black-and-white images that have been character-centered have become more and more halftone images and solid images typified by photographs. Yes. In particular, image quality with respect to changes in halftone density and solid image density when used continuously is increasing year by year, and it is desired to suppress these image changes.

  In order to provide better electrophotographic photoreceptors with higher image quality and higher durability in recent years, the electrical blocking function is maintained and the problems of electrical characteristics and background contamination are solved more than ever. There is a need to. However, the techniques described in Patent Documents 1 to 20 described above have an advantage that the electrical blocking function can be maintained. On the other hand, for example, there is a case where it is difficult to sufficiently suppress an increase in the bright part potential. There is an urgent need to develop a technology that can simultaneously satisfy both the maintenance of the blocking function and the suppression of the bright portion potential rise.

Further, in order to disperse the fine particles of the undercoat layer, there is one using an oil-soluble surfactant having a hydrophilic group and a lipophilic group.
However, since the oil-soluble surfactant does not have any part in the molecule that contributes to binding to the binder resin, it can be dissolved in the upper coating liquid by applying the upper coating liquid to the surface of the undercoat layer. Therefore, it cannot be a means for maintaining the electrical blocking function and preventing the electrical characteristics and the occurrence of soiling.

  Moreover, although it is about a protective layer, it is described in patent document 21 that the dispersion stability of a filler is improved by adding the wet dispersing agent containing a hydrophilic group. However, this adsorbs the wetting and dispersing agent to the polar group on the filler surface that becomes a charge trap site, and in the present invention, the functional group of the crosslinkable resin and the hydroxyl group are appropriately contained by moisture contained in the resin. This is fundamentally different from those in which the hydrophilic group is bonded to the crosslinkable resin in a state in which the hydrophilic fine particles are highly dispersed by binding the hydroxyl group of the compound having an alkyl skeleton.

JP 2005-92216 A US Pat. No. 6,015,645 Japanese Patent Application Laid-Open No. 08-220790 US Pat. No. 5,789,127 JP 2006-71665 A Japanese Patent Laid-Open No. 2005-91981 JP-A-2005-37480 JP 2005-37583 A JP 2005-181678 A JP 2006-47870 A JP-A-46-47344 JP 52-100240 A Japanese Patent Laid-Open No. 54-151843 JP-A-1-118848 JP-A-5-27469 JP-A-9-319128 JP 2000-321805 A JP-A-4-353858 Japanese Patent Laid-Open No. 2004-307809 Japanese Patent Application Laid-Open No. 08-262776 JP 2003-149849 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photosensitive member, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus that are less likely to cause the above-described electrical characteristics and the occurrence of background contamination.

  As a result of extensive studies, the present inventors have provided a conductive support, an undercoat layer provided on the conductive support, and a photosensitive layer provided on the undercoat layer. It has been found that the object can be achieved when the pulling layer comprises a compound having a hydroxyl group and a linear alkyl skeleton, a crosslinkable resin, and fine particles, and the present invention has been completed.

That is, the above-mentioned problem comprises (1) “conductive support, an undercoat layer provided on the conductive support, and a photosensitive layer provided on the undercoat layer of the present invention,
The undercoat layer includes a compound having at least a hydroxyl group and a linear alkyl skeleton, a crosslinkable resin, and hydrophilic fine particles.
An electrophotographic photoreceptor characterized by that, "
(2) “The compound having a hydroxyl group and a linear alkyl skeleton is represented by the following general formula (1).
The electrophotographic photosensitive member according to item (1), wherein:

但し、Ｒは直鎖アルキル骨格を表す」、
（３）「前記直鎖アルキル骨格Ｒの炭素数が、６以上、１５以下である、
ことを特徴とする前記第（１）項または第（２）項に記載の電子写真感光体」、
（４）「前記架橋性樹脂は、水溶性樹脂、アルコール可溶性樹脂、三次元網目構造を形成する硬化型樹脂である、
ことを特徴とする前記第（１）項乃至第（３）項の何れか１項に記載の電子写真感光体」、
（５）「前記架橋性樹脂は、アルキド樹脂及び／又はメラミン樹脂である、
ことを特徴とする前記第（１）項乃至第（４）項の何れか１項に記載の電子写真感光体」、
（６）「前記親水性微粒子が、無機微粒子（Ｐ１）である、
ことを特徴とする前記第（１）項乃至第（５）項の何れか１項に記載の電子写真感光体」、
（７）「前記無機微粒子（Ｐ１）が、酸化亜鉛、酸化スズ、酸化チタンから選ばれる少なくとも１種である、
ことを特徴とする前記第（６）項に記載の電子写真感光体」、
（８）「前記導電性支持体と前記下引き層との間に、電荷ブロッキング層を有する、
ことを特徴とする前記第（１）項乃至第（７）項の何れか１項に記載の電子写真感光体」、
（９）「前記電荷ブロッキング層が、少なくともＮ−アルコキシメチル化ナイロンを含む、
ことを特徴とする前記第（８）項に記載の電子写真感光体」、
（１０）「前記感光層上に保護層を有する、
ことを特徴とする前記第（１）項乃至第（９）項に記載の電子写真感光体」、
（１１）「前記保護層が、少なくとも無機微粒子（Ｐ２）を含む、
ことを特徴とする前記第（１０）項に記載の電子写真感光体」、
（１２）「前記無機微粒子（Ｐ２）が、酸化アルミニウム、酸化ケイ素、酸化チタンから選ばれる少なくとも１種である、
ことを特徴とする前記第（１１）項に記載の電子写真感光体」、
（１３）「前記保護層が、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とを硬化した架橋型保護層である、
ことを特徴とする前記第（１０）項に記載の電子写真感光体」、
（１４）「前記保護層に用いられる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の官能基が、アクリロイルオキシ基及び／又はメタクリロイルオキシ基である、
ことを特徴とする前記第（１３）項に記載の電子写真感光体」、
（１５）「前記保護層に用いられる電荷輸送性構造を有するラジカル重合性化合物の官能基が、アクリロイルオキシ基又はメタクリロイルオキシ基である、
ことを特徴とする前記第（１３）項または第（１４）項に記載の電子写真感光体」、
（１６）「前記保護層に用いられる電荷輸送性構造を有するラジカル重合性化合物の電荷輸送構造が、トリアリールアミン構造である、
ことを特徴とする前記第（１３）項乃至第（１５）項の何れか１項に記載の電子写真感光体」、
（１７）「前記保護層に用いられる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（２）又は（３）の一種以上である、
ことを特徴とする前記第（１３）項乃至第（１６）項の何れか１項に記載の電子写真感光体；

Where R represents a linear alkyl skeleton "
(3) "The carbon number of the linear alkyl skeleton R is 6 or more and 15 or less."
The electrophotographic photosensitive member according to item (1) or (2), wherein:
(4) “The crosslinkable resin is a water-soluble resin, an alcohol-soluble resin, or a curable resin that forms a three-dimensional network structure.
The electrophotographic photosensitive member according to any one of items (1) to (3), wherein:
(5) “The crosslinkable resin is an alkyd resin and / or a melamine resin.
The electrophotographic photosensitive member according to any one of items (1) to (4), wherein:
(6) “The hydrophilic fine particles are inorganic fine particles (P1).
The electrophotographic photosensitive member according to any one of items (1) to (5), wherein:
(7) "The inorganic fine particles (P1) are at least one selected from zinc oxide, tin oxide, and titanium oxide."
The electrophotographic photosensitive member according to item (6), wherein:
(8) “having a charge blocking layer between the conductive support and the undercoat layer,
The electrophotographic photosensitive member according to any one of items (1) to (7), wherein:
(9) "The charge blocking layer contains at least N-alkoxymethylated nylon,
The electrophotographic photosensitive member according to item (8), wherein:
(10) “having a protective layer on the photosensitive layer,
The electrophotographic photosensitive member according to any one of (1) to (9) above,
(11) “The protective layer contains at least inorganic fine particles (P2).
The electrophotographic photosensitive member according to item (10), wherein:
(12) "The inorganic fine particles (P2) are at least one selected from aluminum oxide, silicon oxide, and titanium oxide."
The electrophotographic photosensitive member according to item (11), wherein:
(13) “The protective layer is a crosslinked protective layer 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.
The electrophotographic photosensitive member according to item (10), wherein:
(14) “The functional group of the tri- or higher functional radical polymerizable monomer having no charge transport structure used in the protective layer is an acryloyloxy group and / or a methacryloyloxy group.
The electrophotographic photosensitive member according to item (13), wherein:
(15) "The functional group of the radical polymerizable compound having a charge transporting structure used for the protective layer is an acryloyloxy group or a methacryloyloxy group."
The electrophotographic photosensitive member according to item (13) or (14), wherein:
(16) “The charge transport structure of the radical polymerizable compound having a charge transport structure used in the protective layer is a triarylamine structure.
The electrophotographic photosensitive member according to any one of (13) to (15), wherein:
(17) “The radical polymerizable compound having a charge transporting structure used in the protective layer is one or more of the following general formula (2) or (3).
The electrophotographic photosensitive member according to any one of items (13) to (16), wherein:

（式中、Ｒ１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、−ＣＯＯＲ７（Ｒ７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ＣＯＮＲ８Ｒ９（Ｒ８及びＲ９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、Ａｒ１、Ａｒ２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。Ａｒ３、Ａｒ４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。）」、
（１８）「前記保護層に用いられる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（４）の一種以上である、
ことを特徴とする前記第（１７）項に記載の電子写真感光体；

(In the formula, R1 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, or a nitro group. , An alkoxy group, —COOR7 (R7 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), a carbonyl halide group Or CONR8R9 (R8 and R9 are a hydrogen atom, a halogen 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; Ar1 and Ar2 represent a substituted or unsubstituted arylene group, and may be the same or different.Ar3 and Ar4 may be substituted or unsubstituted. 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, sulfur An atom and a vinylene group, Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether divalent group, and an alkyleneoxycarbonyl divalent group, m and n represent an integer of 0 to 3.) "
(18) "The radical polymerizable compound having a charge transporting structure used in the protective layer is one or more of the following general formula (4).
The electrophotographic photosensitive member according to item (17), wherein:

（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。）」により解決される。
また、上記課題は、本発明の（１９）「前記第（１）項乃至第（１８）項の何れか１項に記載の電子写真感光体を有する、
ことを特徴とする画像形成装置」により解決される。
また、上記課題は、本発明の（２０）「帯電手段、露光手段、現像手段、転写手段及びクリーニング手段からなる群より選ばれる少なくとも１つの手段と、前記第（１）項乃至第（１８）項の何れか１項に記載の電子写真感光体とを一体に保持すると共に、画像形成装置本体に対し着脱自在の構造を有する、
ことを特徴とするプロセスカートリッジ」により解決される。
また、上記課題は、本発明の（２１）「前記第（１）項乃至第（１８）項の何れか１項に記載の電子写真感光体を用いる、
ことを特徴とする画像形成方法」によって解決される。

Represents. ) ”.
In addition, the above-described problem includes the electrophotographic photosensitive member according to any one of (19) “(1) to (18)” of the present invention.
The image forming apparatus is characterized by the above.
Further, the above-mentioned problems are solved by (20) “at least one means selected from the group consisting of charging means, exposure means, developing means, transfer means, and cleaning means, and the above-mentioned items (1) to (18). The electrophotographic photosensitive member according to any one of the items is integrally held and has a structure that is detachable from the image forming apparatus main body.
The process cartridge is characterized by the above.
Further, the above-described problem is achieved by using the electrophotographic photosensitive member according to any one of (21) “(1) to (18)” of the present invention.
The image forming method is characterized by the above.

In the present invention, a compound having a specific functional group (hydroxyl group) having reactivity with a functional group (amino group or the like) possessed by the crosslinkable resin and a linear alkyl skeleton having an appropriate length is used. Excellent image characteristics due to good electrical blocking properties of the undercoat layer on the electrophotographic photosensitive member in which an appropriate range of electrical characteristics is maintained due to the effect of controlling the distance between particles due to good dispersion of fine particles. can get.
The reason why the above-described effect can be obtained by the present invention is not clear, but the present inventor presumes as follows.

The physical properties such as the electron transport properties of the fine particles contained in the undercoat layer are governed by the particle size of the fine particles, the distance between the particles, and the like. In particular, it is a very important issue to freely design and build a fine structure for a material having a submicron-order microstructure of inorganic and organic materials.
A chemical approach that meets these requirements includes the use of fine particle organization. It is necessary to use the particle-substrate interface or particle-particle interface interaction for the organization of fine particles, but the fine particles themselves can interact with functional groups and ligands that have a high affinity with the fine particle surface. If it is possible to apply organic ligands of various lengths having functional groups at both ends as (wetting) dispersants, fine particles with a more advanced structure using the interaction between the ligands Can be expected.
As a compound for dispersing the hydrophilic fine particles, for example, a simple alkane compound does not have a reactive functional group such as a hydroxyl group, and therefore, a crosslinkable resin (binder resin: main resin + crosslinking agent) in the undercoat layer. ), The compound remains in the undercoat layer, and when the upper coating liquid is applied, it moves to the upper layer, causing a decrease in sensitivity and an increase in residual potential, effectively functioning. Can not.
On the other hand, in the electrophotographic photosensitive member of the present invention, as a compound for dispersing hydrophilic fine particles, a compound having a hydroxyl group and a linear alkyl skeleton is added to the surface of the fine particles as a (wetting) dispersant. By changing the alkyl chain length of the compound, the distance between the fine particles can be controlled, and once the undercoat layer is formed, the compound is bonded to the crosslinkable resin (with the undercoat layer). It is considered that the fine particles can be uniformly dispersed in the crosslinkable resin according to the alkyl chain length.
As a result, a subbing layer having a fine structure in which fine particles are regularly arranged in three dimensions is formed, and not only is it effective in preventing leakage of the injected charge from the conductive support to the subbing layer. It is considered that the number of charge traps existing in the charge conduction path is reduced, uniform film formation is possible, and image degradation caused by leakage resistance and an increase in residual potential due to repeated use can be suppressed.
In other words, since the fine particles are regularly arranged three-dimensionally to obtain an undercoat layer exhibiting excellent rectifying properties, not only the bright portion potential is prevented from rising, but also charge injection from the support does not occur. The electrical blocking function is also enhanced, and it is considered that the electrical blocking function and the electrical characteristics can be achieved at a high level.

The presence of fine particles in the polymer has a great influence not only on the direct interface but also on the properties of the polymer around the fine particles, and this affected polymer layer is called an interfacial intermediate layer.
In the present invention, an intermediate layer model as shown in FIG. 10 can be considered. In this intermediate layer, the binder resin is adsorbed on the surface of the fine particles and the binder resin is constrained, and exhibits a behavior different from that of a normal binder resin.
Here, the aggregation of fine particles due to polymer crosslinking may be due to nonionic polymers or ionic polymers, but in any case, the polymer has a strong affinity with the fine particle surface, and the fine particle surface is saturated and adsorbed by the polymer. If not, aggregation occurs.
Since aggregation occurs when one polymer is adsorbed on the bare surface of two fine particles, the probability of aggregation is proportional to the product of the coverage of the adsorption sites by the polymer and the uncovered site of the partner fine particles.
When a compound having a hydroxyl group and a linear alkyl skeleton is added to the system, the compound having a hydroxyl group and a linear alkyl skeleton when the surface of the fine particle is hydrophilic at the adsorption site uncoated portion of the partner fine particle Since the hydroxyl group of the polymer is directed to the fine particle side and the linear alkyl skeleton is directed to the solution side, the surface of the fine particle is strongly lyophilic and the fine particle is dispersed. Fine particles stabilized with an amphiphile such as a compound having a hydroxyl group and a linear alkyl skeleton are more stable due to steric hindrance of the adsorption layer than fine particles stabilized only with electric charge. Conceivable.

Hereinafter, the present invention will be described in detail.
As described above, the present invention uses a coating solution containing at least a compound having a hydroxyl group and a linear alkyl skeleton, a crosslinkable resin, and hydrophilic fine particles, and the conductive support constituting the electrophotographic photosensitive member. An undercoat layer is formed on the body. The electrophotographic photoreceptor having the undercoat layer of the present invention will be described below.

The undercoat layer is a layer having a function of preventing the generation of moire images (interference fringes) due to light interference inside the photosensitive layer when writing with coherent light such as laser light.
Basically, it has a function of causing light scattering of the writing light. In order to exhibit such a function, it is effective that the undercoat layer has a material having a large refractive index, and it contains inorganic fine particles (P1) and a crosslinkable resin (binder resin: main resin + crosslinking agent). The inorganic fine particles (P1) are dispersed in the crosslinkable resin, and are different from the charge blocking layer that does not have a moire prevention function.

A compound having a hydroxyl group and a linear alkyl skeleton is bonded to a binding resin (such as an alkyd resin) and a portion that is strongly adsorbed on the surface of hydrophilic fine particles to prevent the fine particles from attracting each other (preventing aggregation). It is necessary to have a moiety and a solvated moiety that is compatible with the solvent.
As the compound having a hydroxyl group and a linear alkyl skeleton, a compound having a hydroxyl group (hydrophilic functional group) structure as a part contributing to adsorption to fine particles and binding to a binder resin is used.
That is, the hydroxyl group is strongly adsorbed on the surface of the hydrophilic fine particle by the action of physical adsorption and the like with the hydroxyl group present on the surface of the hydrophilic fine particle, and the action of the functional group of the binder resin and ring-opening polymerization at the time of heat. It is considered to be firmly bonded to the crosslinkable resin.
Further, it is preferable that the solvated portion has a small adsorption to the hydrophilic fine particles, dissolves well in the dispersion medium, and has compatibility with the resin. In the present invention, a solvation moiety having a linear alkyl skeleton structure is used.
As described above, the compound used for dispersing the hydrophilic fine particles needs to have a hydroxyl group. The hydroxyl group has high reactivity with a functional group having an active hydrogen such as an amino group. For example, when an alkyd resin having a hydroxyl group is used as a binder resin (main resin) for an undercoat layer and a melamine resin having an amino group or the like is used as a crosslinker for the undercoat layer, the heat of the undercoat layer coating solution In the time-drying process, the hydroxyl group easily reacts with the amino group of the melamine resin, the compound having the group can be immobilized in the undercoat layer, and an electrophotographic photoreceptor can be effectively realized. .
The carbon number of the linear alkyl skeleton of the compound having a hydroxyl group and a linear alkyl skeleton is preferably 6-15, and more preferably 8-14.
When the carbon number of the linear alkyl skeleton is 6 or more, the steric hindrance effect due to the lipophilic group (hydrocarbon chain) is large, the effect of preventing fine particle aggregation is large, and when the carbon number is 15 or less, the hydrophilic group The effect of hydrophobic interaction between lipophilic groups is smaller than the adsorption effect of. As a result, the dispersion state of the hydrophilic fine particles in the undercoat layer can be stably maintained, and the antifouling effect can be enhanced.

Preferable examples of the compound having a hydroxyl group and a linear alkyl skeleton in the present invention include, for example, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, 1-undecanol, 1-dodecanol, Examples include, but are not limited to, 1-tridecanol, 1-tetradecanol, and 1-pentadecanol. Further, two or more of these compounds may be used in combination.
The amount of the compound having a hydroxyl group and a linear alkyl skeleton contained in the undercoat layer of the present invention is 0.01 to 50 parts by weight, preferably 0.1 to 20 parts by weight with respect to 100 parts by weight of the binder resin. Parts by weight. If the addition amount of the compound having a hydroxyl group and a linear alkyl skeleton is too small, the surface of the fine particles cannot be covered, and the fine particles are likely to aggregate, and the dispersion effect of the fine particles by the compound becomes insufficient. On the other hand, if the amount of the compound having a hydroxyl group and a linear alkyl skeleton is too large, the residual potential is increased.
As the hydrophilic fine particles to be contained in the undercoat layer, inorganic fine particles or surface-treated organic fine particles can be used.
In particular, inorganic fine particles are preferable because they have a relatively high refractive index and can effectively prevent moiré that occurs when an image is written with coherent light such as laser light.

  The surface of the hydrophilic fine particles used for the undercoat layer is hydrophilic, and the compound having a hydroxyl group and a linear alkyl skeleton is adsorbed on the surface, and is preferably inorganic fine particles (P1).

In addition, the undercoat layer needs to obtain an appropriate resistance in order to obtain leakage resistance.
By including the inorganic fine particles in the undercoat layer, the volume resistance of the undercoat layer and its environmental dependency can be easily and reliably controlled, and both the leak prevention property and the electrical characteristics are further improved. This is preferable.
Therefore, it is possible to effectively prevent “soil stain” when the charge transport layer is thickened.

Since the charge moving through the undercoat layer is mainly electrons, the inorganic fine particles (P1) are preferably N-type semiconductor particles.
The undercoat layer containing N-type semiconductive particles in an insulating binder effectively blocks hole injection from the conductive support, and has a property of transporting electrons from the photosensitive layer. Have
As a result, the rectifying property of the undercoat layer is improved, the occurrence of black spots and background stains is prevented, and the developability is increased, so that an electrophotographic image having high gradation and good sharpness can be obtained.

The specific resistance value of the inorganic fine particles is preferably 10 ⁷ Ω · cm or more and 10 ¹³ Ω · cm or less. If it is 10 ¹³ Ω · cm or more, the effect of preventing soiling is increased, but the bright part potential is increased, and if it is 10 ⁷ Ω · cm or less, the effect of preventing soiling is reduced.

As the inorganic fine particles (P1), for example, zinc oxide, lead white, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, magnesium oxide, antimony oxide, bismuth oxide, silicon oxide, tin are doped. Examples thereof include indium oxide, tin oxide doped with antimony and tantalum, and zirconium oxide. Among these, use of zinc oxide, tin oxide, and titanium oxide is desirable.
In particular, titanium oxide hardly absorbs visible light and near-infrared light and is white, which is desirable for increasing the sensitivity of the photoreceptor. Titanium oxide has a relatively high refractive index, and can effectively prevent the generation of abnormal images of interference fringe patterns that occur when writing images with coherent light such as laser light. From the viewpoint, it is preferable.
Further, two or more kinds of inorganic fine particles can be selected from the above materials and used in combination.

  There are rutile type, anatase type, brookite type and amorphous type as the crystal type of titanium oxide, any crystal type may be used, and any titanium oxide of needle-like crystals and granular crystals may be used alone or in combination. Although it can be used, in the present invention, the rutile crystal form is particularly preferred.

The average primary particle size of the inorganic fine particles (P1) contained in the undercoat layer is preferably 0.05 to 1 μm, and more preferably 0.1 to 0.5 μm. When the average primary particle size of the inorganic fine particles exceeds this range, the dispersibility in the binder resin is lowered, and as a result, it tends to be difficult to achieve both leak prevention properties and electrical characteristics.
Further, as is apparent from FIGS. 1 to 6, from the viewpoint of preventing residual potential, the undercoat layer of the present invention has a function capable of moving at least the same charge as the charge charged on the surface of the photoreceptor. preferable. For this reason, for example, in the case of a negatively charged type photoreceptor, it is desirable to impart electron conductivity to the undercoat layer, and the fine particles used should have electron conductivity or be conductive. Is desirable. Alternatively, the use of an electron conductive material (for example, an acceptor) for the undercoat layer makes the effect of the present invention more remarkable.

It is important that the crosslinkable resin used for the undercoat layer is not affected by the coating solvent for the photosensitive layer in consideration of laminating the photosensitive layer on the undercoat layer.
Moreover, it is preferable that it is resin which has active hydrogen, such as an amino group. For example, water-soluble resins such as polyvinyl alcohol and casein, alcohol-soluble resins such as copolymer nylon resins, curable resins that form a three-dimensional network structure such as melamine resins, phenol resins, and alkyd resins can be used.
Among them, the alkyd resin is preferable as a crosslinkable resin because excellent solvent resistance can be obtained by using it alone or in combination with a crosslinking agent and the dependency of the resistance value on environmental change is small.

In addition, since the amino group has high reactivity (crosslinkability) with respect to the hydroxyl group, the alkyd resin can be used alone, but it is very preferable to use, for example, a melamine resin having an amino group.
At this time, the mixing ratio of the alkyd resin and the melamine resin is an important factor that determines the structure and characteristics of the undercoat layer. A range in which the ratio (weight ratio) between the two is 5/5 to 8/2 can be cited as a good mixing ratio range. If the melamine resin is richer than 5/5, volume shrinkage is increased during thermosetting, and coating film defects are likely to occur, or the residual potential of the photoreceptor is increased. Further, if the alkyd resin is richer than 8/2, although it is effective for reducing the residual potential of the photoreceptor, the bulk resistance becomes too low and the soiling becomes worse, which is not desirable. When a curable resin is used as the binder resin for the undercoat layer, the binder material contained in the undercoat layer coating solution is a monomer and / or oligomer of the curable resin.
The undercoat layer may contain a crosslinking agent as necessary. When the functional group of the alkyd resin and the functional group of the crosslinking agent are chemically bonded and the resin is cured, it is possible to improve the film forming property and the adhesiveness between the conductive support and the photosensitive layer.

  Preferable examples of the crosslinking agent include a blocked isocyanate compound, a melamine resin, an epoxy compound and the like, and it is desirable that the functional group used for crosslinking reacts without excess or deficiency. Among them, melamine resin is most suitable from the viewpoint of coating film performance (adhesion, corrosion resistance, chemical resistance, etc.).

  In the undercoat layer, the weight ratio between the inorganic fine particles and the crosslinkable resin determines important characteristics. For this reason, it is important that the weight ratio of the metal oxide and the crosslinkable resin is in the range of 3/1 to 8/1. Depending on the specific volume of the metal oxide, if the weight ratio of the two is less than 3/1, not only the charge transport ability of the undercoat layer decreases, but also the increase in residual potential in repeated use increases. Responsiveness may decrease. When the weight ratio between the two is larger than 8/1, voids in the undercoat layer increase, and bubbles may be generated when a photosensitive layer is applied on the undercoat layer.

  On the other hand, in the region where the volume ratio exceeds 3/1, not only the binding ability of the crosslinkable resin is inferior, but also the surface property of the coating film is deteriorated, which may adversely affect the film forming property of the upper photosensitive layer. This effect can be a serious problem when the photosensitive layer is a laminated type and a thin layer such as a charge generation layer is formed. When the volume ratio exceeds 3/1, there are cases where the surface of the inorganic fine particles cannot be completely covered with the binder resin, and the direct contact with the charge generation material increases the probability of heat carrier generation, resulting in soil contamination. May be adversely affected.

  The thickness of the undercoat layer is 1 to 10 μm, preferably 2 to 5 μm. If the film thickness is less than 1 μm, the effect is small, and if it exceeds 10 μm, residual potential may be accumulated, which is not desirable.

As a method for forming the undercoat layer, wet coating methods such as blade coating, dip coating, spray coating, ring coating, and beet coating are employed.
Solvents used in the undercoat layer coating solution include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin In the case where a charge blocking layer is provided in the lower layer, a solvent that does not erode this is used.
The inorganic fine particles (P1), the crosslinkable resin, the solvent, etc. are not pulverized using a dispersion medium such as a ball mill, a vertical sand mill, a horizontal sand mill, a paint conditioner, or a dispersion medium, for example, an ultrasonic dispersion method. It is dispersed in the binder resin by a roll mill, an impact mill or the like.

  As the ratio of the hydrophilic fine particles and the crosslinkable resin (binder resin: main resin + crosslinking agent), the ratio described above is optimal, but the solid content concentration relative to the total coating liquid amount at the time of dispersion is the total coating liquid amount. 50 wt% or less is desirable. The reason for this is not clear, but when the amount of hydrophilic fine particles and crosslinkable resin increases as a whole, the proportion of primary particles increases as hydrophilic fine particles, and the crosslinkable resin is saturated with respect to solubility in a solvent. Therefore, there is a high risk of causing recrystallization of the crosslinkable resin or reaggregation of primary particles due to pressure or temperature. For this reason, the dispersion stability of the coating liquid for the undercoat layer is reduced, or a large amount of undispersed material immediately after dispersion is generated. The prepared undercoat layer coating solution is applied onto a conductive support and dried to form an undercoat layer.

Hereinafter, the present invention will be described according to the layer structure.
<About the layer structure of the electrophotographic photoreceptor>
Next, the electrophotographic photoreceptor of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing a configuration example of an electrophotographic photosensitive member used in the present invention, in which an undercoat layer (53) and a photosensitive layer (56) are sequentially laminated on a conductive support (51). It has a configuration.
In this case, the photosensitive layer (56) may have a laminated structure of a charge generation layer (54) and a charge transport layer (55) as shown in FIG. 2, and is formed on the photosensitive layer (56) as shown in FIG. A protective layer (57) may be provided.
As shown in FIG. 4, a charge blocking layer (52) may be provided between the conductive support (51) and the undercoat layer (53).
FIG. 5 is a cross-sectional view showing another structural example of the electrophotographic photosensitive member used in the present invention. According to the previous example, the charge blocking layer (52) and the undercoat layer (53) are formed on the conductive support. The charge generation layer (54) and the charge transport layer (55) are stacked in this order.
FIG. 6 is a cross-sectional view showing still another example of the structure of the electrophotographic photosensitive member used in the present invention. This is similar to the previous example, on the conductive support (51), the charge blocking layer (52), An undercoat layer (53), a charge generation layer (54), a charge transport layer (55), and a protective layer (57) are sequentially laminated.
Among the configurations shown in FIGS. 1 to 6, the photoconductors shown in FIGS. 3 and 6 are most preferably used.

<About conductive support>
Examples of the conductive support include those having a volume resistance of 10 ¹⁰ Ω · cm or less, such as metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, and platinum, tin oxide, and indium oxide. After metal oxide is deposited or sputtered, film or cylindrical plastic, paper coated, or aluminum, aluminum alloy, nickel, stainless steel, etc. Pipes that have been subjected to surface treatment such as cutting, super-finishing, and polishing can be used. Further, endless nickel belts and endless stainless steel belts disclosed in JP-A-52-36016 can also be used as the conductive support.
In addition, those obtained by dispersing and coating conductive powder in an appropriate binder resin on the support can also be used as the conductive support of the present invention.
Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc and silver, or metal oxide powder such as conductive tin oxide and ITO. Can be mentioned. The binder resin used at the same time is polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. , Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, Examples thereof include thermoplastic, thermosetting resins, and photocurable resins such as melamine resin, urethane resin, phenol resin, and alkyd resin. Such a conductive layer can be provided by dispersing and coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.
Furthermore, 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 of the present invention.

<About the charge blocking layer>
By laminating the charge blocking layer with the undercoat layer to prevent moiré, a material different from that of the undercoat layer can be used, and the degree of design freedom for the imaging member can be expanded.
That is, the charge blocking layer can provide a single function of preventing the generation of moire without giving a plurality of functions to the undercoat layer, and can further improve the moire prevention effect. Is preferably provided.

The charge blocking layer is a layer having a function of preventing reverse polarity charges induced on the electrode (conductive support) during charging of the photosensitive member from being injected into the photosensitive layer from the support. In the case of negative charging, it has a function of preventing hole injection, and in the case of positive charging, it has a function of preventing electron injection.
In addition, a conductive polymer having a rectifying property or an acceptor (donor) resin / compound may be added in accordance with the charging polarity to provide a function of suppressing charge injection from the substrate.
The N-alkoxymethylated nylon used in the electrophotographic photoreceptor charge blocking layer of the present invention is polyamide 6, polyamide 12, or copolymer polyamide containing these as constituents, for example, T.I. L. It can be obtained by modification by the method proposed by Cairns (J. Am. Chem. Soc. 71. P651 (1949)). N-alkoxymethylated nylon is obtained by replacing the amide bond hydrogen of the original polyamide with an alkoxymethyl group and is soluble in methyl alcohol, ethyl alcohol or isopropyl alcohol, and particularly has high solubility in lower alcohols. Therefore, N-alkoxymethylated nylon is preferable because it can form a charge blocking layer without being dissolved in a ketone solvent such as methyl ethyl ketone.

  The N-alkoxymethylated nylon used in the present invention is preferably used since N-alkoxymethylated nylon having an alkoxy group having 1 to 10 carbon atoms has good solubility in a solvent for preparing a coating solution. it can. Examples of the N-alkoxymethylated nylon having an alkoxy group having 1 to 10 carbon atoms include methoxymethylated nylon, ethoxymethylated nylon, butoxymethylated nylon and the like. Of these, methoxymethylated nylon can be most preferably used.

  The substitution rate can be selected in a wide range depending on the modification conditions, but 20 to 40 mol% is preferable in terms of environmental stability because the hygroscopicity of the charge blocking layer is suppressed. Furthermore, when the substitution rate is less than 20 mol%, the solubility of the resulting resin in the solvent decreases, and solvent coating becomes difficult. In particular, the solubility in lower alcohols (methanol, ethanol, etc.) is significantly reduced.

As the coating solvent for the charge blocking layer, alcohol solvents such as methanol, ethanol, propanol, butanol, or a mixed solvent thereof are used because N-alkoxymethylated nylon exhibits alcohol solubility. Among these, N-alkoxymethylated nylon used in the present invention has the highest solubility in methanol, and therefore methanol is most suitable as the alcohol solvent.
However, when methanol alone is used as a coating solvent, since the evaporation rate of the solvent is large and the latent heat is large, a coating film defect called brushing is generated at the time of coating film touch drying. Therefore, in order to avoid this, it is preferable to use an alcohol solvent having a slower evaporation rate than methanol (a combination of two or more alcohol solvents). As an alcohol solvent other than methanol, an effect of preventing brushing cannot be obtained with a solvent having a carbon number not so large, and therefore an alcohol solvent having 3 or more carbon atoms is preferably used. For example, n-propanol, iso-propanol, n-butanol, iso-butanol, tert-butanol, n-pentanol and the like can be mentioned. When the carbon number is too large, not only the touch drying time is lengthened but also the solubility of N-alkoxymethylated nylon is lowered. Therefore, a carbon number of about 6 or less is appropriate.

  Further, by adding water as a mixed solvent in addition to the alcohol solvent, the compatibility between the N-alkoxymethylated nylon and the alcohol solvent is increased, and the temporal stability of the coating liquid is increased. preferable. As content rate of the water in a solvent, 5-20 wt% is more preferable in the surface of coexistence of coating-film property and liquid stability. In addition, this content rate is represented by weight% of the water in all the solvents used for a coating liquid.

As water used in the present invention, tap water can be used, but distilled water from which impurities are eliminated, ion-exchanged water, etc. are suitable, and further, a filtration step is performed with a filter of an appropriate size. More preferably, it has passed.
In addition, fine particles and additives (for example, an electron-accepting substance, a curing agent, a dispersing agent, etc.) may be added according to the design of the charge blocking layer produced using this coating solution. Moreover, you may add organic solvents other than alcohol solvent as needed.

  The film thickness of the charge blocking layer is 0.1 μm or more and less than 2.0 μm, preferably 0.5 μm or more and 1.0 μm or less. When the charge blocking layer becomes thick, the residual potential increases remarkably at low temperature and low humidity due to repeated charging and exposure, and when the film thickness is too thin, the blocking effect is reduced. In addition, the charge blocking layer may contain chemicals, solvents, additives, curing accelerators, etc. necessary for curing (crosslinking) as necessary, and blade coating, dip coating, spray coating, beat coating, etc., in a conventional manner. It is formed on the substrate by a nozzle coating method or the like. After the coating, it is dried or cured by a curing process such as drying, heating, or light.

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

<Photosensitive layer comprising a charge generation layer and a charge transport layer>
(Charge generation layer)
The charge generation layer is a layer mainly composed of a charge generation material having a charge generation function, and a binder resin can be used in combination as necessary. As the charge generation material, inorganic materials and organic materials can be used.
Inorganic materials include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compounds, and amorphous silicon. In amorphous silicon, dangling bonds that are terminated with hydrogen atoms or halogen atoms, or those that are doped with boron atoms, phosphorus atoms, or the like are preferably used.
On the other hand, a known material can be used as the organic material. For example, phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, azulenium salt pigments, squaric acid methine pigments, azo pigments having carbazole skeleton, azo pigments having triphenylamine skeleton, azo pigments having diphenylamine skeleton, dibenzothiophene skeleton Azo pigments having 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. These charge generation materials can be used alone or as a mixture of two or more.
As a binder resin used as necessary for the charge generation layer, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, Examples include polyacrylamide. These binder resins can be used alone or as a mixture of two or more. In addition to the binder resin described above as a binder resin for the charge generation layer, a polymer charge transport material having a charge transport function, such as an arylamine skeleton, benzidine skeleton, hydrazone skeleton, carbazole skeleton, stilbene skeleton, pyrazoline skeleton, etc. Polymer materials such as polycarbonate, polyester, polyurethane, polyether, polysiloxane, and acrylic resin, polymer materials having a polysilane skeleton, and the like can be used.
Moreover, a polysilylene polymer is illustrated as a specific example of the latter.

The charge generation layer may contain a low molecular charge transport material.
Low molecular charge transport materials that can be used in the charge generation layer include hole transport materials and electron transport materials.
Examples of the electron transporting material include chloroanil, bromanyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide and diphenoquinone derivatives. These electron transport materials can be used alone or as a mixture of two or more.
Examples of the hole transporting material include the electron donating materials shown below and are used favorably. As hole transport materials, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triaryls Other known materials such as methane derivatives, 9-styrylanthracene derivatives, pyrazoline derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, bisstilbene derivatives, enamine derivatives, and the like can be given. These hole transport materials can be used alone or as a mixture of two or more.
Methods for forming the charge generation layer include a vacuum thin film preparation method and a casting method from a solution dispersion system.
As the former method, a vacuum deposition method, a glow discharge decomposition method, an ion plating method, a sputtering method, a reactive sputtering method, a CVD method, or the like is used, and the above-described inorganic materials and organic materials can be satisfactorily formed.
In addition, in order to provide a charge generation layer by the casting method described later, if necessary, the inorganic or organic charge generation material together with a binder resin, tetrahydrofuran, dioxane, dioxolane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, cyclohexane. Can be formed by dispersing with a ball mill, attritor, sand mill, bead mill, etc. using a solvent such as pentanone, anisole, xylene, methyl ethyl ketone, acetone, ethyl acetate, butyl acetate, etc. . Moreover, leveling agents, such as a dimethyl silicone oil and a methylphenyl silicone oil, can be added as needed. The application can be performed by dip coating, spray coating, bead coating, ring coating, or the like.
The thickness of the charge generation layer provided as described above is suitably about 0.01 to 5 μm, preferably 0.05 to 2 μm.

(About charge transport layer)
The charge transport layer is a layer having a charge transport function, and the crosslinked protective layer having a charge transport structure of the present invention is useful as a charge transport layer. When the crosslinkable protective layer is the entire charge transport layer, the radical polymerizable composition of the present invention (radical polymerization having no charge transportable structure) is formed on the charge generation layer as described in the method for preparing a crosslinkable protective layer described later. A coating solution containing a polymerizable monomer and a radically polymerizable compound having a charge transporting structure; the same shall apply hereinafter), and if necessary, after drying, a curing reaction is initiated by external energy to form a crosslinked protective layer. The At this time, the film thickness of the crosslinked protective layer is 10 to 30 μm, preferably 10 to 25 μm. If it is thinner than 10 μm, a sufficient charging potential cannot be maintained, and if it is thicker than 30 μm, peeling from the lower layer tends to occur due to volume shrinkage during curing.
In addition, when the crosslinkable protective layer is formed on the surface portion of the charge transport layer and the charge transport layer has a laminated structure, the lower layer portion of the charge transport layer contains a charge transport material having a charge transport function and a binder resin in a suitable solvent. It is dissolved or dispersed in, and formed on the charge generation layer by coating and drying, and a coating solution containing the radical polymerizable composition of the present invention is coated thereon 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 can be used. As described above, the use of the polymer charge transport material can reduce the solubility of the lower layer when the surface layer is applied, and is particularly useful.
As the binder resin, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, Polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin And thermoplastic or thermosetting resins such as phenol resins and alkyd resins.
The amount of the charge transport material is appropriately 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. However, when a polymer charge transport material is used, it can be used alone or in combination with a binder resin.
As the solvent used for coating the lower layer portion of the charge transport layer, the same solvent as that for the charge generation layer can be used, but a solvent that dissolves the charge transport material and the binder resin well is suitable. These solvents may be used alone or in combination of two or more. In addition, the same coating method as that for the charge generation layer can be used to form the lower layer portion of the charge transport layer.
If necessary, a plasticizer and a leveling agent can be added.
As a plasticizer that can be used in combination with the lower layer portion of the charge transport layer, those used as plasticizers for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is 100 parts by weight of the binder resin. On the other hand, about 0 to 30 parts by weight is appropriate.
As a leveling agent that can be used in combination with the lower layer portion of the charge transport layer, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain are used. About 0 to 1 part by weight is appropriate for 100 parts by weight of the binder resin.
The thickness of the lower layer portion of the charge transport layer is appropriately about 5 to 40 μm, preferably about 10 to 30 μm.

<Single photosensitive layer>
The photosensitive layer having a single layer structure is a layer having a charge generation function and a charge transport function at the same time, and the crosslinked protective layer having a charge transport structure of the present invention is a single layer by containing a charge generation material having a charge generation function. It is useful as a photosensitive layer having a structure. As described in the method for forming a charge generation layer, the charge generation material is dispersed together with a coating liquid containing a radical polymerizable composition, applied onto the charge generation layer, dried as necessary, and then external energy. By this, the curing reaction is started and a cross-linked protective layer is formed. In addition, you may add the liquid in which the electric charge generation material was previously disperse | distributed with the solvent to this coating liquid for crosslinking type protective layers. At this time, the film thickness of the crosslinked protective layer is 10 to 30 μm, preferably 10 to 25 μm. If the thickness is less than 10 μm, a sufficient charging potential cannot be maintained. If the thickness is more than 30 μm, peeling from the conductive substrate or the undercoat layer tends to occur due to volume shrinkage during curing.
In addition, when the crosslinkable protective layer is a surface portion of a photosensitive layer having a single layer structure, the lower layer portion of the photosensitive layer is appropriately formed of a charge generation material having a charge generation function, a charge transport material having a charge transport function, and a binder resin. It can be formed by dissolving or dispersing in a solvent, coating and drying. Moreover, a plasticizer, a leveling agent, etc. can also be added as needed. As the charge generation material dispersion method, the charge generation material, the charge transport material, the plasticizer, and the leveling agent may be the same as those already described in the charge generation layer and the charge transport layer. As the binder resin, in addition to the binder resin previously mentioned in the section of the charge transport layer, the binder resin mentioned in the charge generation layer may be mixed and used. In addition, the above-described polymer charge transport materials can be used, which is useful in that the mixing of the lower layer photosensitive layer composition into the crosslinked protective layer can be reduced. The thickness of the lower layer portion of the photosensitive layer is suitably about 5 to 30 μm, preferably about 10 to 25 μm.
The charge generation material contained in the photosensitive layer having a single layer structure is preferably 1 to 30% by weight based on the total amount of the photosensitive layer, and the binder resin contained in the lower layer portion of the photosensitive layer is 20 to 80% by weight of the total amount. The transport material is preferably used in an amount of 10 to 70 parts by weight.

<About protective layer>
In the electrophotographic photoreceptor of the present invention, a protective layer can be provided on the photosensitive layer for the purpose of protecting the photosensitive layer. In recent years, computers have been used on a daily basis, and it has been desired to reduce the size of the apparatus together with high-speed output by a printer. Therefore, by providing a protective layer and improving the durability, it is possible to effectively use the photosensitive member of the present invention having no abnormal defect.
Materials used for the protective layer include ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone, polybutylene, Polybutylene terephthalate, polycarbonate, polyarylate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylbenten, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane, polychlorinated Examples thereof include resins such as vinyl, polyvinylidene chloride, and epoxy resin. Of these, polycarbonate or polyarylate can be most preferably used.

(Fine particle dispersion type protective layer)
In addition to the protective layer, fluorine resins such as polytetrafluoroethylene, silicone resins, and inorganic fine particles such as titanium oxide, tin oxide, potassium titanate, and silicon oxide (P2). ), And organic fine particles dispersed therein can be added.
Among the fine particle materials used for the protective layer of the photoreceptor, examples of the organic fine particle material include fluorine resin powder such as polytetrafluoroethylene, silicone resin powder, a-carbon powder, and the like. Materials include metal powders such as copper, tin, aluminum, indium, silicon dioxide, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, tin oxide doped with antimony, tin-doped indium oxide Inorganic materials such as metal oxides such as potassium titanate. In particular, from the viewpoint of the hardness of the fine particles, it is advantageous to use an inorganic material. In particular, silicon dioxide, titanium oxide, and aluminum oxide can be used effectively.
The concentration of fine particles in the protective layer varies depending on the type of fine particles used and also on the electrophotographic process conditions using the photoreceptor, but the ratio of fine particles to the total solid content on the outermost layer side of the protective layer is preferably 5% by weight or more, preferably It is 10% by weight or more and 50% by weight or less, preferably about 30% by weight or less.
The volume average particle size of the fine particles used is preferably in the range of 0.1 μm to 2 μm, and preferably in the range of 0.3 μm to 1 μm. In this case, if the average particle size is too small, the wear resistance is not sufficiently exhibited, and if it is too large, the surface property of the coating film is deteriorated or the coating film itself cannot be formed.
The average particle size of the fine particles in the present invention is a volume average particle size unless otherwise specified, and is determined by an ultracentrifugal automatic particle size distribution analyzer: CAPA-700 (manufactured by Horiba). At this time, the particle size (Median system) corresponding to 50% of the cumulative distribution was calculated. In addition, it is important that the standard deviation of each particle measured simultaneously is 1 μm or less. If the standard deviation is larger than this, the particle size distribution may be too wide, and the effects of the present invention may not be obtained remarkably.
In addition, among these fine particles, α-aluminum oxide having a hexagonal close-packed structure, which has high insulating properties, high thermal stability and high wear resistance, suppresses image blur and improves wear resistance. It is particularly useful in terms of points.
Further, these fine particles can be surface-treated with at least one kind of surface treatment agent, which is preferable from the viewpoint of dispersibility of the fine particles. Decrease in the dispersibility of the fine particles not only increases the residual potential, but also decreases the transparency of the coating, causes defects in the coating, and decreases the wear resistance. It can develop into a big problem. As the surface treating agent, all conventionally used surface treating agents can be used, but a surface treating agent capable of maintaining the insulating properties of the fine particles is preferable. For example, titanate coupling agents, aluminum coupling agents, zircoaluminate coupling agents, higher fatty acids, etc., or mixed treatment with these and silane coupling agents, Al2O3, TiO2, ZrO2, silicone, aluminum stearate Or a mixture treatment thereof is more preferable from the viewpoints of fine particle dispersibility and image blur. The treatment with the silane coupling agent is strongly influenced by image blur, but the influence may be suppressed by performing a mixing treatment of the surface treatment agent and the silane coupling agent. The surface treatment amount varies depending on the average primary particle size of the fine particles used, but is preferably 3 to 30 wt%, more preferably 5 to 20 wt%. If the surface treatment amount is less than this, the effect of dispersing fine particles cannot be obtained, and if it is too much, the residual potential is significantly increased. These fine particle materials may be used alone or in combination of two or more. The surface treatment amount of the fine particles is defined by the weight ratio of the surface treatment agent to be used with respect to the fine particle amount as described above.
These fine particle materials can be dispersed by using an appropriate disperser. Further, from the viewpoint of the transmittance of the protective layer, it is preferable that the fine particles used are dispersed to the primary particle level and have less aggregates.
Further, the protective layer may contain a charge transport material for reducing residual potential and improving responsiveness. As the charge transport material, the materials described in the description of the charge transport layer can be used. When a low molecular charge transport material is used as the charge transport material, a concentration gradient in the protective layer may be provided. In order to improve wear resistance, it is an effective means to reduce the concentration of the surface side. The concentration referred to here represents the ratio of the weight of the low molecular charge transporting material to the total weight of all the materials constituting the protective layer, and the concentration gradient is a gradient that lowers the concentration on the surface side in the above weight ratio. It shows that. The use of a polymer charge transport material is very advantageous in terms of enhancing the durability of the photoreceptor.
As a method for forming the protective layer, a solvent content at the time of forming the coating film and a method of reducing the contact time with the solvent are preferable. Specifically, a spray coating method, a ring coating method in which the amount of coating liquid is regulated is used. Particularly preferred.

(Crosslinked protective layer)
Further, as another type of protective layer, a cross-linked protective layer having a charge transporting structure is effectively used. By using a cross-linked protective layer having a charge transporting structure, it is possible to more efficiently realize an increase in electric field strength due to repeated use, and it is effective in suppressing scumming. In addition, since the surface of the photoconductor is highly scratch resistant and filming and the like are less likely to occur, it has an effect of reducing the occurrence of image defects, and is effective and useful for realizing high durability. Furthermore, the homogeneity of the cross-linked protective layer is higher than that of the fine particle-dispersed protective layer in terms of homogeneity as the protective layer. This can be used more effectively than the fine particle-dispersed protective layer because the abrasion of the photosensitive member surface layer due to the cleaning member or the like becomes uniform and the electrostatic property of the photosensitive member in the minute region becomes uniform. In short, in the present invention, the protective layer provided on the photosensitive layer has at least a trifunctional or higher-functional radical polymerizable monomer having no charge transport structure and a crosslinkable protection obtained by curing a radical polymerizable compound having a charge transport structure. By being a layer, an electrophotographic photosensitive member having high durability and realizing high image quality over a long period of time can be achieved.
In the photoreceptor of the present invention, by using a radically polymerizable monomer having three or more functional groups for the surface layer, a three-dimensional network structure is developed, and a high hardness surface layer having a very high degree of crosslinking is obtained, and a high resistance to resistance is obtained. Abrasion is achieved. On the other hand, when only monofunctional and bifunctional radically polymerizable monomers are used, the cross-linking bond in the cross-linkable protective layer becomes dilute, and a dramatic improvement in wear resistance cannot be achieved. When a polymer material is contained in the crosslinkable protective layer, the development of the three-dimensional network structure is inhibited and the degree of crosslinkage is lowered, so that sufficient wear resistance cannot be obtained as compared with the present invention. Furthermore, the compatibility between the polymer material contained and the cured product resulting from the reaction of the radically polymerizable composition (radical polymerizable monomer or compound having a charge transporting structure) is poor, and local wear due to phase separation is poor. Appear and appear as a scratch on the surface. Moreover, the coating liquid for the crosslinkable protective layer of the present invention contains a radical polymerizable compound having a charge transporting structure, and this is taken into the crosslink during the curing of the above trifunctional or higher radical polymerizable monomer. On the other hand, when a low molecular charge transport material having no functional group is contained in the crosslinkable protective layer, precipitation of the low molecular charge transport material and white turbidity occur due to its low compatibility, and the crosslinkable protective layer The mechanical strength of the steel also decreases. When a bifunctional or higher-functional charge transporting compound is used as the main component, it is fixed in the crosslinked structure with multiple bonds, but the charge transporting structure is very bulky, so that distortion occurs in the cured resin and crosslinking protection The internal stress of the layer increases, and cracks and scratches frequently occur due to carrier adhesion and the like.
Furthermore, the photoreceptor of the present invention has good electrical characteristics, and thus high image quality can be realized over a long period of time. This is because a radically polymerizable compound having a charge transporting structure is used and immobilized in a pendant shape between crosslinks. As described above, the charge transport material having no functional group causes precipitation and clouding phenomenon, and deterioration due to repeated use such as reduction in sensitivity and increase in residual potential is remarkable. When a bifunctional or higher-functional charge transporting compound is used as the main component, it is fixed in the crosslinked structure with a plurality of bonds, so the intermediate structure (cation radical) during charge transport cannot be kept stable, The sensitivity decreases due to the trap, and the residual potential increases. Such deterioration of the electrical characteristics appears as an image such as a decrease in image density and thinning of characters.

Next, the constituent material of the crosslinking type protective layer coating solution of the present invention will be described.
The trifunctional or higher functional radical polymerizable monomer having no charge transporting property used in the present invention is a hole transporting structure such as triarylamine, hydrazone, pyrazoline, carbazole, such as condensed polycyclic quinone, diphenoquinone, cyano group. And a monomer having no electron transport structure such as an electron-withdrawing aromatic ring having a nitro group and having three or more radical 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、Ｘ１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（Ｒ１０）−基（Ｒ１０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。
（２）１，１−置換エチレン官能基としては、例えば以下の式で表わされる官能基が挙げられる。

(However, in the formula, X1 is an arylene group such as a phenylene group and a naphthylene group which may have a substituent, an alkenylene group which may have a substituent, a —CO— group, a —COO— group, -CON (R10)-group (R10 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 represents an -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、−ＣＯＯＲ１１基（Ｒ１１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−ＣＯＮＲ１２Ｒ１３（Ｒ１２およびＲ１３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、Ｘ２は上記式１０のＸ１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，Ｘ２の少なくとも何れか一方がオキシカルボニル基、シアノ基、アルケニレン基、及び芳香族環である。）
これらの置換基を具体的に例示すると、α−塩化アクリロイルオキシ基、メタクリロイルオキシ基、α−シアノエチレン基、α−シアノアクリロイルオキシ基、α−シアノフェニレン基、メタクリロイルアミノ基等が挙げられる。
なお、これらＸ１，Ｘ２、Ｙについての置換基にさらに置換される置換基としては、例えばハロゲン原子、ニトロ基、シアノ基、メチル基、エチル基等のアルキル基、メトキシ基、エトキシ基等のアルコキシ基、フェノキシ基等のアリールオキシ基、フェニル基、ナフチル基等のアリール基、ベンジル基、フェネチル基等のアラルキル基等が挙げられる。
これらのラジカル重合性官能基の中では、特にアクリロイルオキシ基、メタクリロイルオキシ基が有用であり、３個以上のアクリロイルオキシ基を有する化合物は、例えば水酸基がその分子中に３個以上ある化合物とアクリル酸（塩）、アクリル酸ハライド、アクリル酸エステルを用い、エステル反応あるいはエステル交換反応させることにより得ることができる。また、３個以上のメタクリロイルオキシ基を有する化合物も同様にして得ることができる。また、ラジカル重合性官能基を３個以上有する単量体中のラジカル重合性官能基は、同一でも異なっても良い。

(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, -COOR11 group (R11 is a hydrogen atom, an alkyl group such as an optionally substituted methyl group, ethyl group, Aralkyl groups such as benzyl and phenethyl groups which may have substituents, aryl groups such as phenyl groups and naphthyl groups which may have substituents, or -CONR12R13 (R12 and R13 are hydrogen atoms, substituents Aralkyl such as methyl group and ethyl group which may have a group, benzyl group, naphthylmethyl group and phenethyl group which may have a substituent Or an aryl group such as a phenyl group or a naphthyl group which may have a substituent, which may be the same or different from each other), and X2 is the same as the substituent and the same as X1 in the formula 10 above. Represents a bond or an alkylene group, provided that at least one of Y and X2 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.
Examples of the substituent further substituted on the substituents for X1, X2, and Y include, for example, an alkyl group such as a halogen atom, a nitro group, a cyano group, a methyl group, and an ethyl group, and an alkoxy group such as a methoxy group and an ethoxy group. Group, aryloxy groups such as phenoxy group, aryl groups such as phenyl group and naphthyl group, aralkyl groups such as benzyl group and phenethyl group, and the like.
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 modified (hereinafter ECH modified) Acrylate, glycerol EO modified triacrylate, glycerol PO modified triacrylate, tris (acryloxyethyl) isocyanurate, dipentaerythritol hexaacrylate (DPHA), dipentaerythritol caprolactone modified hexaacrylate, dipentaerythritol hydroxypentaacrylate, alkylated di Pentaerythritol pentaacrylate, alkylated dipentaerythritol tetraacrylate, alkylated dipentaerythritol triacrylate, dimethylolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, phosphoric acid EO-modified triacrylate, 2, 2, 5, 5 , -Tetrahydroxymethylcyclopentanone tetraacrylate And the like, which can be used in combination either alone or in combination.
In addition, the trifunctional or higher functional radical polymerizable monomer having no charge transport structure used in the present invention has a functional group ratio (molecular weight / functional group number) in order to form a dense crosslink in the crosslinkable protective layer. 250 or less is desirable. When the functional group ratio is larger than 250, the cross-linked protective layer is soft and wear resistance is somewhat lowered. Therefore, among the monomers exemplified above, monomers having a modifying group such as EO, PO, caprolactone are extremely It is not preferable to use a compound having a long modifying group alone. Further, the proportion of the trifunctional or higher functional radical polymerizable monomer having no charge transporting 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 protective layer. It substantially depends on the proportion 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 crosslink density of the crosslinkable protective layer is small, and a drastic improvement in wear resistance is not achieved as compared with the case of using a conventional thermoplastic binder resin. On the other hand, if it exceeds 80% by weight, the content of the charge transporting compound is lowered, and the electrical characteristics are deteriorated. Since the required wear resistance and electrical characteristics differ depending on the process used, it cannot be said unconditionally, but considering the balance of both characteristics, the range of 30 to 70% by weight is most preferable.
The 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. A compound having an electron transport structure such as an electron-withdrawing aromatic ring and having one radical polymerizable functional group. Examples of the radical polymerizable functional group include functional groups represented by the above formula 10 or formula 11. More specifically, those shown in the above radical polymerizable monomer can be mentioned, and acryloyloxy group and methacryloyloxy group are particularly useful. In addition, a triarylamine structure is highly effective as a charge transporting structure, and in particular, 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 good. To last.

（式中、Ｒ１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、−ＣＯＯＲ７（Ｒ７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ＣＯＮＲ８Ｒ９（Ｒ８及びＲ９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、Ａｒ１、Ａｒ２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。Ａｒ３、Ａｒ４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, R1 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, or a nitro group. , An alkoxy group, —COOR7 (R7 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), a carbonyl halide group Or CONR8R9 (R8 and R9 are a hydrogen atom, a halogen 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; Ar1 and Ar2 represent a substituted or unsubstituted arylene group, and may be the same or different.Ar3 and Ar4 may be substituted or unsubstituted. 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, sulfur An atom and a vinylene group, Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether divalent group, and an alkyleneoxycarbonyl divalent group, m and n represent an integer of 0 to 3.)

Specific examples of general formulas (1) and (2) are shown below.
In the general formulas (1) and (2), in the substituent of R1, as the alkyl group, for example, a methyl group, an ethyl group, a propyl group, a butyl group, etc., as the aryl group, a phenyl group, a naphthyl group, etc. Examples of the aralkyl group include a benzyl group, a phenethyl group, and a naphthylmethyl group, and examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group. These include a halogen atom, a nitro group, a cyano group, 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. Also good.
Of the substituents for R1, particularly preferred are a hydrogen atom and a methyl group.
Substituted or unsubstituted Ar3 and Ar4 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.
The aryl group represented by Ar3 and Ar4 may have a substituent as shown below, for example.
(1) Halogen atom, cyano group, nitro group and the like.
(2) Alkyl groups, preferably C1-C12, especially C1-C8, more preferably C1-C4 linear or branched alkyl groups, and these alkyl groups further include a fluorine atom, a hydroxyl group, a cyano group, It may have a phenyl group substituted with a C1-C4 alkoxy group, a phenyl group or a halogen atom, a C1-C4 alkyl group, or a C1-C4 alkoxy group. Specifically, methyl group, ethyl group, n-butyl group, i-propyl group, t-butyl group, s-butyl group, n-propyl group, trifluoromethyl group, 2-hydroxyethyl group, 2-ethoxyethyl Group, 2-cyanoethyl group, 2-methoxyethyl group, benzyl group, 4-chlorobenzyl group, 4-methylbenzyl group, 4-phenylbenzyl group and the like.
(3) An alkoxy group (-OR2), wherein R2 represents the alkyl group defined in (2). 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. This may contain a C1-C4 alkoxy group, a C1-C4 alkyl group or a halogen atom 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、Ｒ３及びＲ４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Ｃ１〜Ｃ４のアルコキシ基、Ｃ１〜Ｃ４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。Ｒ３及びＲ４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。
前記Ａｒ１、Ａｒ２で表わされるアリーレン基としては、前記Ａｒ３、Ａｒ４で表されるアリール基から誘導される２価基である。
前記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。ただし、上記ｍが０の場合はＸは単結合でない方が好ましい。
置換もしくは無置換のアルキレン基としては、Ｃ１〜Ｃ１２、好ましくはＣ１〜Ｃ８、さらに好ましくはＣ１〜Ｃ４の直鎖または分岐鎖のアルキレン基であり、これらのアルキレン基にはさらにフッ素原子、水酸基、シアノ基、Ｃ１〜Ｃ４のアルコキシ基、フェニル基又はハロゲン原子、Ｃ１〜Ｃ４のアルキル基もしくはＣ１〜Ｃ４のアルコキシ基で置換されたフェニル基を有していてもよい。具体的にはメチレン基、エチレン基、ｎ−ブチレン基、ｉ−プロピレン基、ｔ−ブチレン基、ｓ−ブチレン基、ｎ−プロピレン基、トリフルオロメチレン基、２−ヒドロキエチレン基、２−エトキシエチレン基、２−シアノエチレン基、２−メトキシエチレン基、ベンジリデン基、フェニルエチレン基、４−クロロフェニルエチレン基、４−メチルフェニルエチレン基、４−ビフェニルエチレン基等が挙げられる。
置換もしくは無置換のシクロアルキレン基としては、Ｃ５〜Ｃ７の環状アルキレン基であり、これらの環状アルキレン基にはフッ素原子、水酸基、Ｃ１〜Ｃ４のアルキル基、Ｃ１〜Ｃ４のアルコキシ基を有していても良い。具体的にはシクロヘキシリデン基、シクロへキシレン基、３，３−ジメチルシクロヘキシリデン基等が挙げられる。
置換もしくは無置換のアルキレンエーテル基としては、エチレンオキシ、プロピレンオキシ、エチレングリコール、プロピレングリコール、ジエチレングリコール、テトラエチレングリコール、トリプロピレングリコールを表わし、アルキレンエーテル基アルキレン基はヒドロキシル基、メチル基、エチル基等の置換基を有してもよい。
ビニレン基は、

(In the formula, R3 and R4 each independently represents 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. A C1-C4 alkoxy group, a C1-C4 alkyl group or a halogen atom may be contained as a substituent. R3 and R4 may form a ring together)
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 Ar1 and Ar2 is a divalent group derived from the aryl group represented by Ar3 or Ar4.
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. However, when m is 0, X is preferably not a single bond.
The substituted or unsubstituted alkylene group is a C1-C12, preferably C1-C8, more preferably a C1-C4 linear or branched alkylene group, and these alkylene groups further include a fluorine atom, a hydroxyl group, It may have a cyano group, a C1-C4 alkoxy group, a phenyl group or a halogen atom, a C1-C4 alkyl group, or a phenyl group substituted with a C1-C4 alkoxy group. 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 is a C5-C7 cyclic alkylene group, and these cyclic alkylene groups have a fluorine atom, a hydroxyl group, a C1-C4 alkyl group, and a C1-C4 alkoxy group. May be. 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、
Ｒ５は水素、アルキル基（前記（２）で定義されるアルキル基と同じ）、アリール基（前記Ａｒ３、Ａｒ４で表わされるアリール基と同じ）、ａは１または２、ｂは１〜３を表わす。
前記Ｚは置換もしくは未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。
置換もしくは未置換のアルキレン基としは、前記Ｘのアルキレン基と同様なものが挙げられる。
置換もしくは無置換のアルキレンエーテル２価基としては、前記Ｘのアルキレンエーテル基の２価基が挙げられる。
アルキレンオキシカルボニル２価基としては、カプロラクトン変性２価基が挙げられる。

Represented by
R5 is hydrogen, an alkyl group (same as the alkyl group defined in (2) above), an aryl group (same as the aryl group represented by Ar3 or Ar4 above), a is 1 or 2, and b is 1-3. .
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 radically polymerizable compound having a charge transport structure of the present invention is more preferably a compound having the structure of the following general formula (3).

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

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

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

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 monofunctional 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, but are not limited to the 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 crosslinkable protective layer, and this component is 20 to 80% by weight based on the total amount of the crosslinkable protective layer. It is preferably 30 to 70% by weight. If this component is less than 20% by weight, the charge transport performance of the cross-linked protective layer cannot be maintained sufficiently, and repeated use causes deterioration of electrical characteristics such as a decrease in sensitivity and an increase in residual potential. 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. Although the electrical characteristics and abrasion resistance required differ depending on the process used, it cannot be said unconditionally, but considering the balance of both characteristics, the range of 30 to 70% by weight is most preferable.

The 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. Monofunctional and bifunctional radically polymerizable monomers and radically polymerizable oligomers can be used in combination for the purpose of adjustment, imparting functions such as stress relaxation of the crosslinkable protective layer, lowering the surface energy and reducing the 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 crosslink density of the crosslinkable protective 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.
In addition, the crosslinkable protective 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. In order to make the process proceed efficiently, a polymerization initiator may be used.

Examples of the thermal polymerization initiator include 2,5-dimethylhexane-2,5-dihydroperoxide, dicumyl peroxide, benzoyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di ( Peroxybenzoyl) hexyne-3, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, peroxide initiators such as lauroyl peroxide, azobisisobutylnitrile, azobiscyclohexanecarbonitrile Azo initiators such as methyl azobisisobutyrate, azobisisobutylamidine hydrochloride, 4,4′-azobis-4-cyanovaleric acid.

Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2- Acetophenone-based or ketal-based photopolymerization initiators such as methyl-2-morpholino (4-methylthiophenyl) propan-1-one, 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 protective layer of the present invention is formed by applying and curing a coating solution containing 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. . 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. Ethers such as dichloromethane, halogens 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 application can be performed by dip coating, spray coating, bead coating, ring coating, or the like.

In the present invention, after applying such a coating liquid, energy is applied from the outside and cured to form a crosslinkable protective layer. The external energy used at this time includes heat, light, and radiation. The heat energy is applied by heating from the coating surface side or the support side using a gas such as air or nitrogen, steam, various heat media, infrared rays, or electromagnetic waves. The heating temperature is preferably 100 ° C. or higher and 170 ° C. or lower. If the heating temperature is lower than 100 ° C., the reaction rate is slow and the reaction is not completely completed. When the temperature is higher than 170 ° C., the reaction proceeds non-uniformly and a large strain is generated in the crosslinked protective layer. In order to advance the curing reaction uniformly, it is also effective to complete the reaction by heating at a relatively low temperature of less than 100 ° C. and then heating to 100 ° C. or more. As the energy of light, UV irradiation light sources such as high-pressure mercury lamps and metal halide lamps, which mainly have an emission wavelength in ultraviolet light, can be used, but a visible light source can also be selected according to the absorption wavelength of radically polymerizable substances and photopolymerization initiators. Is possible. The irradiation light quantity is preferably 50 mW / cm 2 or more and 1000 mW / cm 2 or less, and if it is less than 50 mW / cm 2, it takes time for the curing reaction. If it is higher than 1000 mW / cm 2, the progress of the reaction becomes non-uniform, and the crosslinkable protective layer becomes very rough. Examples of radiation energy include those using electron beams. Among these energies, those using heat and light energy are useful because of the ease of reaction rate control and the simplicity of the apparatus.

As for the dilution solvent of the coating solution, if a large amount of a solvent that dissolves the lower layer is used in a large amount, a composition such as a resin binder or a low molecular charge transport material in the lower layer is mixed into the outermost surface layer, which hinders the curing reaction. Instead, it becomes the same state as when a large amount of non-cured material is previously contained in the coating liquid, and non-uniform curing of the crosslinked surface occurs. Conversely, when a solvent that does not dissolve the lower layer at all is used, the adhesion between the crosslinkable protective layer and the lower layer decreases, and crater-like repellency appears in the crosslinkable protective layer due to volume shrinkage during the curing reaction, resulting in a low elastic displacement rate. The lower layer of is partially exposed. These measures include the use of a mixed solvent to control the solubility of the lower layer, the amount of solvent contained in the coating liquid by the liquid composition and coating method, the lower layer component using a polymer charge transport material, etc. And a low-solubility intermediate layer or a good adhesive intermediate layer is provided between the lower layer and the cross-linking protective layer.
In addition, about 0.1-10 micrometers is suitable for the thickness of a protective layer.

<About the intermediate layer>
In the photoreceptor of the present invention, when the protective layer is the surface portion of the photosensitive layer, it is possible to provide an intermediate layer for the purpose of suppressing the mixing of lower layer components into the protective layer or improving the adhesion with the lower layer. is there.
In the intermediate layer, a binder resin is generally used as a main component. Examples of these resins include polyamide, alcohol-soluble nylon, water-soluble polyvinyl butyral, polyvinyl butyral, and polyvinyl alcohol. As a method for forming the intermediate layer, a generally used coating method is employed as described above. The thickness of the intermediate layer is suitably about 0.05 to 2 μm.

<Addition of antioxidant to each layer>
In the present invention, in order to improve environmental resistance, a protective layer, a photosensitive layer, a charge generation layer, a charge transport layer, an undercoat layer, a charge blocking layer are used for the purpose of preventing a decrease in sensitivity and an increase in residual potential. An antioxidant can be added to each layer such as a layer and an intermediate layer.
The following are mentioned as antioxidant which can be used for this invention.
(Phenolic compounds)
2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3,5-di-t-butyl-4 -Hydroxyphenyl) propionate, 2,2'-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2'-methylene-bis- (4-ethyl-6-tert-butylphenol), 4, 4'-thiobis- (3-methyl-6-tert-butylphenol), 4,4'-butylidenebis- (3-methyl-6-tert-butylphenol), 1,1,3-tris- (2-methyl-4 -Hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene- -(3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, bis [3,3'-bis (4'-hydroxy-3'-t-butylphenyl) butyric acid ] Cryol ester, tocopherols and the like.
(Paraphenylenediamines)
N-phenyl-N'-isopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N, N'- Di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine and the like.
(Hydroquinones)
2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- (2-octadecenyl) ) -5-methylhydroquinone and the like.
(Organic sulfur compounds)
Dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate, and the like.
(Organic phosphorus compounds)
Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine, and the like.
These compounds are known as antioxidants such as rubbers, plastics and fats and oils, and commercially available products can be easily obtained.
The addition amount of the antioxidant in the present invention is 0.01 to 10% by weight based on the total weight of the layer to be added.

<Image Forming Method and Apparatus>
Next, the image forming method and the image forming apparatus of the present invention will be described in detail with reference to the drawings.
The image forming method and the image forming apparatus according to the present invention include, for example, at least a process of charging, image exposure, and development of a photosensitive member, and then transferring and fixing a toner image onto an image holding member (transfer paper). An image forming method and an image forming apparatus including a cleaning process.
In some cases, an image forming method or the like in which an electrostatic latent image is directly transferred to a transfer member and developed does not necessarily have the above-described process arranged on a photosensitive member.
FIG. 7 is a schematic diagram illustrating an example of an image forming apparatus. A charging charger (3) is used as a means for charging the photoconductor on average. As the charging means, a corotron device, a scorotron device, a solid discharge element, a needle electrode device, a roller charging device, a conductive brush device, or the like is used, and a known system can be used.
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, a transfer charger (10) is used to transfer the toner image visualized on the photoconductor onto the transfer body (9). In addition, a pre-transfer charger (7) may be used for better transfer. As these transfer means, a transfer charger, an electrostatic transfer method using a bias roller, a mechanical transfer method such as an adhesive transfer method and a pressure transfer method, and a magnetic transfer method can be used. As the electrostatic transfer method, the charging means can be used.
Next, a separation charger (11) and a separation claw (12) are used as means for separating the transfer body (9) from the photoreceptor (1). As other separation means, electrostatic adsorption induction separation, side end belt separation, tip grip conveyance, curvature separation, and the like are used. As the separation charger (11), the charging means can be used.
Next, a fur brush (14) and a cleaning blade (15) are used to clean the toner remaining on the photoreceptor after transfer. Further, a pre-cleaning charger (13) may be used in order to perform cleaning more efficiently. 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 photoreceptor as required. 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.
The 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. 8, 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 Charge Transporting 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）トリアリールアミノ基置換アクリレート化合物（表１中の例示化合物Ｎｏ．５４）
上記（１）で得られたヒドロキシ基置換トリアリールアミン化合物（構造式Ｂ）８２．９ｇ（０．２２７ｍｏｌ）をテトラヒドロフラン４００ｍｌに溶解し、窒素気流中で水酸化ナトリウム水溶液（ＮａＯＨ：１２．４ｇ，水：１００ｍｌ）を滴下した。この溶液を５℃に冷却し、アクリル酸クロライド２５．２ｇ（０．２７２ｍｏｌ）を４０分かけて滴下した。その後、５℃で３時間撹拌し反応を終了させた。この反応液を水に注ぎ、トルエンにて抽出した。この抽出液を炭酸水素ナトリウム水溶液と水で繰り返し洗浄した。その後、このトルエン溶液から溶媒を除去し、カラムクロマト処理（吸着媒体：シリカゲル、展開溶媒：トルエン）にて精製した。得られた無色のオイルにｎ−ヘキサンを加え、結晶を析出させた。この様にして例示化合物Ｎｏ．５４の白色結晶８０．７３ｇ（収率＝８４．８％）を得た。
融点：１１７．５〜１１９．０℃

(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

First, a synthesis example of titanyl phthalocyanine used for the charge generation layer will be described.
(Synthesis Example 1)
A titanyl phthalocyanine crystal was synthesized according to JP 2001-19871 and Example 1. That is, 292 parts of 1,3-diiminoisoindoline and 1800 parts of sulfolane are mixed, and 204 parts of titanium tetrabutoxide are 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.
60 parts of the obtained crude titanyl phthalocyanine pigment washed with hot water were stirred and dissolved in 1000 parts of 96% sulfuric acid at 3 to 5 ° C. and filtered. The obtained sulfuric acid solution was added dropwise to 35000 parts of ice water with stirring, the precipitated crystals were filtered, and then washed with water until the washing solution became neutral to obtain an aqueous paste of titanyl phthalocyanine pigment.
To this water paste, 1500 parts of tetrahydrofuran was added and stirred vigorously (2000 rpm) with a homomixer (Kennis, MARKIIf model) at room temperature. When the dark blue color of the paste changed to light blue (20 minutes after the start of stirring), Stirring was stopped and filtration under reduced pressure was immediately performed. The crystals obtained on the filter were washed with tetrahydrofuran to obtain 98 parts of a pigment wet cake. This was dried under reduced pressure (5 mmHg) at 70 ° C. for 2 days to obtain 78 parts of titanyl phthalocyanine crystals.
The obtained titanyl phthalocyanine powder was subjected to X-ray diffraction spectrum measurement under the following conditions. As a result, the Bragg angle 2θ with respect to Cu-Kα characteristic X-ray (wavelength 1.542 mm) was 27.2 ± 0.2 °, and the maximum peak and minimum Titanyl with a peak at an angle of 7.3 ± 0.2 ° and no peak between the peak at 7.3 ° and the peak at 9.4 ° and no peak at 26.3 ° A phthalocyanine powder was obtained. The result is shown in FIG.
(X-ray diffraction spectrum measurement conditions)
X-ray tube: Cu
Voltage: 50kV
Current: 30mA
Scanning speed: 2 ° / min Scanning range: 3 ° -40 °
Time constant: 2 seconds

Hereinafter, a specific method for producing the photoreceptor will be described.
(1) Photoconductor production example [Preparation of charge blocking layer coating solution]
(Binder resin) N-methoxymethylated nylon (Fine Resin FR-101, manufactured by Lead City Corporation) 4 parts (solvent) Methanol 70 parts by weight (solvent) n-butanol 30 parts by weight The above formulation is uniformly dissolved and dispersed. A charge blocking layer coating solution was obtained.
[Preparation of undercoat layer coating solution 1]
(Binder resin: main resin) Alkyd resin 6 parts by weight (Beckolite M-6401-50, manufactured by Dainippon Ink & Chemicals, Inc.)
(Binder resin: cross-linking agent) Melamine resin 4 parts by weight (Super Becamine G-821-60, manufactured by Dainippon Ink & Chemicals, Inc.)
(Fine particles) 40 parts by mass of hydrophilic titanium oxide (CR-EL (average particle size 0.25 μm), manufactured by Ishihara Sangyo Co., Ltd.)
(Additive) Alcohol-based compound 0.25 parts by weight {1-decanol (product number 23,976-3), manufactured by Sigma-Aldrich Japan Co., Ltd.}
(Solvent) 50 parts by weight of 2-butanone Into the above medium, zirconia beads having a diameter of 2 mm were charged, and at room temperature, 60 minutes at 1500 rpm with a continuous rotation type horizontal shaker (IKA-VIBRAX VXR basic, manufactured by IKA Japan). The mixture was stirred for a minute to obtain an undercoat layer coating solution 1 of 4.37 μm mesh pass.
[Preparation of charge generation layer coating solution]
(Charge generating material) X-ray diffraction spectrum 15 parts by weight of oxotitanium phthalocyanine having the X-ray diffraction spectrum shown in FIG. ) 2-butanone 280 parts by weight PSZ beads having a diameter of 0.5 mm were put into the above medium, and stirred at 1200 rpm for 30 minutes in a commercially available bead mill at room temperature, and a 4.37 μm mesh pass charge generation layer coating solution Got.
[Preparation of coating solution for charge transport layer]
(Charge transport material) Triphenylamine compound (A) 7 parts by mass

（結着樹脂） ポリカーボネート樹脂 １０重量部 （パンライト ＴＳ−２０５０、帝人化成社製）
（レベリング剤） 反応性シリコーンオイル（１重量％テトラヒドロフラン溶液） ０．２重量部 （ＫＦ５０−１００ＣＳ、信越化学工業社製）
（溶媒） テトラヒドロフラン ８０重量部
上記処方を均一に溶解、分散し、電荷輸送層塗工液を得た。
［微粒子分散型保護層塗工液の調製］
（電荷輸送物質） トリフェニルアミン系化合物 （Ａ） ３重量部
（結着樹脂） ポリカーボネート樹脂 ４重量部 （パンライト ＴＳ−２０５０、帝人化成社製）
（微粒子） 酸化アルミニウム ０．７重量部
（スミコランダム ＡＡ−０３、住友化学工業社製、比抵抗１０^１０Ω・ｃｍ以上）
（溶媒） テトラヒドロフラン ２８０重量部
（溶媒） シクロヘキサノン ８０重量部
上記処方を均一に溶解、分散し、微粒子分散型保護層塗工液を得た。
[架橋型保護層塗工液の調製]
（電荷輸送性構造を有さない３官能以上のラジカル重合性化合物） トリメチロールプロパントリアクリレート ５重量部 ｛（ＫＡＹＡＲＡＤ ＴＭＰＴＡ、日本化薬社製） 分子量 ２９６、官能基数 ３、分子量／官能基数＝９９｝
（電荷輸送性構造を有さない３官能以上のラジカル重合性化合物） カプロラクトン変性ジペンタエリスリトールヘキサアクリレート ５重量部 ｛（ＫＡＹＡＲＡＤ ＤＰＣＡ−１２０、日本化薬社製）、分子量 １９４７、官能基数 ６、分子量／官能基数＝３２５｝
（電荷輸送性構造を有するラジカル重合性化合物） 例示化合物Ｎｏ．５４ １０重量部
（光重合開始剤） １−ヒドロキシ−シクロヘキシル−フェニル−ケトン １重量部 （ＩＲＧＡＣＵＲＥ １８４、チバ・スペシャルティ・ケミカルズ社製）
（レベリング剤） 反応性シリコーン化合物 ０．０２重量部 （ＢＹＫ−ＵＶ３５７０、ビックケミー・ジャパン社製）
（溶媒） テトラヒドロフラン １２０重量部
上記処方を均一に溶解、分散し、架橋型保護層塗工液を得た。

(Binder resin) Polycarbonate resin 10 parts by weight (Panlite TS-2050, manufactured by Teijin Chemicals Ltd.)
(Leveling agent) Reactive silicone oil (1 wt% tetrahydrofuran solution) 0.2 parts by weight (KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.)
(Solvent) Tetrahydrofuran 80 parts by weight The above formulation was uniformly dissolved and dispersed to obtain a charge transport layer coating solution.
[Preparation of fine particle dispersion type protective layer coating solution]
(Charge transport material) Triphenylamine compound (A) 3 parts by weight (binder resin) Polycarbonate resin 4 parts by weight (Panlite TS-2050, manufactured by Teijin Chemicals Ltd.)
(Fine particles) 0.7 parts by weight of aluminum oxide (Sumicorundum AA-03, manufactured by Sumitomo Chemical Co., Ltd., specific resistance of 10 ¹⁰ Ω · cm or more)
(Solvent) 280 parts by weight of tetrahydrofuran (solvent) 80 parts by weight of cyclohexanone The above formulation was uniformly dissolved and dispersed to obtain a fine particle-dispersed protective layer coating solution.
[Preparation of crosslinkable protective layer coating solution]
(Trifunctional or higher functional radical polymerizable compound having no charge transporting structure) Trimethylolpropane triacrylate 5 parts by weight {(KAYARAD TMPTA, manufactured by Nippon Kayaku Co., Ltd.) Molecular weight 296, functional group number 3, molecular weight / functional group number = 99 }
(Trifunctional or higher functional radical polymerizable compound having no charge transporting structure) Caprolactone-modified dipentaerythritol hexaacrylate 5 parts by weight {(KAYARAD DPCA-120, manufactured by Nippon Kayaku Co., Ltd.), molecular weight 1947, functional group number 6, molecular weight / Number of functional groups = 325}
(Radical polymerizable compound having a charge transporting structure) 54 10 parts by weight (photopolymerization initiator) 1-hydroxy-cyclohexyl-phenyl-ketone 1 part by weight (IRGACURE 184, manufactured by Ciba Specialty Chemicals)
(Leveling agent) Reactive silicone compound 0.02 parts by weight (BYK-UV3570, manufactured by Big Chemie Japan)
(Solvent) Tetrahydrofuran 120 parts by weight The above formulation was uniformly dissolved and dispersed to obtain a crosslinkable protective layer coating solution.

[Photoconductor Production Example 1]
An aluminum cylinder having a diameter of 30 mm and a length of 340 mm was used as a base. The undercoat layer coating solution 1, the charge generation layer coating solution, and the charge transport layer coating solution were sequentially dip coated on the substrate and dried. Further, the crosslinkable protective layer coating solution was spray-coated under the following conditions and cured with ultraviolet rays to prepare a photoreceptor 1.
First layer (undercoat layer): The undercoat layer coating liquid 1 mainly comprising a titanium oxide powder dispersed in an alkyd resin and a melamine resin. Film thickness 3.5 μm.
Second layer (charge generation layer): The charge generation layer coating solution mainly comprising a dispersion of an oxytitanium phthalocyanine pigment having absorption at a wavelength of 780 nm in a polyvinyl butyral resin. Film thickness 0.2 μm.
Third layer (charge transport layer): The charge transport layer coating solution mainly comprising a hole-transporting triphenylamine compound dissolved in a polycarbonate resin at a mass ratio of 7:10. Film thickness 27 μm.
Fourth layer (protective layer): Mainly composed of a radical polymerizable compound having a charge transporting structure dissolved in a trifunctional or higher functional radical polymerizable compound having no charge transporting structure at a mass ratio of 10:10. The crosslinkable protective layer coating solution. Film thickness 5 μm.
[Spray application conditions]
Coating liquid discharge amount: 10 mL / min Coating liquid discharge pressure: 3.0 kgf / cm ²
Rotation speed of workpiece: 168rpm
Application speed: 10.7 mm / s
Distance between spray gun head and coated object: 50 mm
Number of coatings: Once [UV curing conditions]
Light source: Metal halide lamp Light source power: 160 W / cm 100%
Distance between light source and object to be coated: 110 mm
Rotation speed of workpiece: 25rpm
Irradiation time: 240s
Object temperature control: 30 ° C

[Photoconductor Production Example 2]
Undercoat layer coating solution similar to undercoat layer coating solution 1 except that 1-hexanol (product number H1,330-3, manufactured by Sigma-Aldrich Japan) is used as the alcohol compound. Photoconductor 2 was prepared in the same manner as Photoconductor 1, except that No. 2 was used.

[Photoconductor Production Example 3]
Undercoat layer coating solution similar to undercoat layer coating solution 1 except that 1-octanol (product number 29,788-7, manufactured by Sigma-Aldrich Japan) is used as the alcohol compound. A photoconductor 3 was produced in the same manner as the photoconductor 1 except that 3 was used.

[Photoconductor Production Example 4]
Undercoat layer coating solution similar to undercoat layer coating solution 1 except that 1-dodecanol (product number 12,679-9, manufactured by Sigma-Aldrich Japan) is used as the alcohol compound. A photoconductor 4 was prepared in the same manner as the photoconductor 1 except that 4 was used.

[Photoconductor Production Example 5]
Undercoat layer coating similar to undercoat layer coating solution 1 except that 1-tetradecanol (product number 18,538-8, manufactured by Sigma-Aldrich Japan) is used as the alcohol compound. A photoconductor 5 was produced in the same manner as the photoconductor 1 except that the working solution 5 was used.

[Photoconductor Production Example 6]
Except for using 1-hexadecanol (product number 25,874-1, manufactured by Sigma-Aldrich Japan) as the alcohol compound, the photoreceptor 1 except that the undercoat layer coating solution 6 is used. A photoreceptor 6 was produced in the same manner as described above.

[Photoconductor Production Example 7]
Undercoat layer coating similar to undercoat layer coating solution 1 except that 1-octadecanol (product number 25,876-8, manufactured by Sigma-Aldrich Japan) is used as the alcohol compound. A photoconductor 7 was produced in the same manner as the photoconductor 1 except that the working solution 7 was used.

[Photoconductor Production Example 8]
The undercoat layer coating solution similar to the undercoat layer coating solution 1 except that 1-butanol (product number 28,154-9, manufactured by Sigma-Aldrich Japan) is used as the alcohol compound. A photoconductor 8 was produced in the same manner as the photoconductor 1 except that 8 was used.

[Photoconductor Production Example 9]
Undercoat layer coating similar to the undercoat layer coating solution 1 except that 1-pentanol (product number 13,897-5, manufactured by Sigma-Aldrich Japan) is used as the alcohol compound. A photoconductor 9 was produced in the same manner as the photoconductor 1 except that the liquid 9 was used.

[Photoconductor Production Example 10]
A photoconductor 10 was produced in the same manner as in [Photoconductor Production Example 1] except that the undercoat layer coating solution 10 having the formulation shown below was used. The thickness of the obtained undercoat layer is 3.5 μm.
[Preparation of undercoat layer coating solution]
(Binder resin: main resin) Alkyd resin 6 parts by weight (Beckolite M-6401-50, manufactured by Dainippon Ink & Chemicals, Inc.)
(Binder resin: cross-linking agent) Melamine resin 4 parts by weight (Super Becamine G-821-60, manufactured by Dainippon Ink & Chemicals, Inc.)
(Fine particles) 40 parts by weight of titanium oxide (CR-EL, manufactured by Ishihara Sangyo Co., Ltd. (average particle size 0.25 μm))
(Solvent) 2-butanone 50 parts by weight Into the above medium, zirconia beads having a diameter of 2 mm are charged, and at room temperature, 60 minutes at 1500 rpm with a continuous rotation type horizontal shaker (IKA-VIBRAX VXR basic, manufactured by IKA Japan). The mixture was stirred for a minute to obtain an undercoat layer coating solution of 4.37 μm mesh pass.

[Photosensitive body production example 11]
As a prescription of the charge blocking layer coating solution, the coating solution prepared in [Preparation of charge blocking layer coating solution] is used, except that a charge blocking layer is provided between the conductive support and the undercoat layer. Produced Photoreceptor 11 in the same manner as [Production Example 1 of Photoreceptor]. The film thickness of the obtained charge blocking layer was 0.75 μm.

[Photoconductor Production Example 12]
Except that the coating liquid prepared in [Preparation of fine particle dispersion type protective layer coating liquid] was used as the prescription of the protective layer coating liquid, and the coating and curing conditions of the protective layer coating liquid were changed as shown below. Thus, a photoconductor 12 was produced in the same manner as in [Photoconductor Production Example 1]. The film thickness of the obtained protective layer is 5 μm.
[Spray application conditions]
Coating liquid discharge amount: 15 mL / min Coating liquid discharge pressure: 2.0 kgf / cm ²
Coating object rotation speed: 120rpm
Application speed: 7.14 mm / s
Distance between spray gun head and coated object: 50 mm
Number of applications: 2 times [thermal curing conditions]
Atmospheric temperature: 150 ° C
Curing time: 20 minutes

[Photoconductor Production Example 13]
Photoreceptor in the same manner as [Photoreceptor Production Example 12] except that the undercoat layer coating solution 2 prepared in [Photoreceptor Production Example 2] is used as the formulation of the undercoat layer coating solution. 13 was produced.

[Photoconductor Production Example 14]
Photoreceptor in the same manner as [Photoreceptor Production Example 12] except that the undercoat layer coating solution 3 prepared in [Photoreceptor Production Example 3] is used as the formulation of the undercoat layer coating solution. 14 was produced.

[Photoconductor Production Example 15]
Photoreceptor in the same manner as [Photoreceptor Production Example 12] except that the undercoat layer coating solution 4 prepared in [Photoreceptor Production Example 4] is used as the formulation of the undercoat layer coating solution. 15 was produced.

[Photoconductor Production Example 16]
Photoreceptor in the same manner as [Photoreceptor Production Example 12] except that the undercoat layer coating solution 5 prepared in [Photoreceptor Production Example 5] is used as the formulation of the undercoat layer coating solution. 16 was produced.

[Photoconductor Production Example 17]
Photoreceptor in the same manner as [Photoreceptor Production Example 12] except that the undercoat layer coating solution 6 prepared in [Photoreceptor Production Example 6] is used as the formulation of the undercoat layer coating solution. 17 was produced.

[Photoconductor Production Example 18]
Photoreceptor in the same manner as [Photoreceptor Production Example 12] except that the undercoat layer coating solution 7 prepared in [Photoreceptor Production Example 7] is used as the formulation of the undercoat layer coating solution. 18 was produced.

[Photoconductor Production Example 19]
Photoreceptor in the same manner as [Photoreceptor Production Example 12] except that the undercoat layer coating solution 8 prepared in [Photoreceptor Production Example 8] is used as the formulation of the undercoat layer coating solution. 19 was produced.

[Photoconductor Production Example 20]
Photoreceptor in the same manner as [Photoreceptor Production Example 12] except that the undercoat layer coating solution 9 prepared in [Photoreceptor Production Example 9] is used as the formulation of the undercoat layer coating solution. 20 was produced.

[Photoconductor Production Example 21]
Photoreceptor in the same manner as [Photoreceptor Production Example 12] except that the undercoat layer coating solution 10 prepared in [Photoreceptor Production Example 10] is used as the formulation of the undercoat layer coating solution. 21 was produced.

[Photoconductor Production Example 22]
As a prescription of the charge blocking layer coating solution, the coating solution prepared in [Preparation of charge blocking layer coating solution] is used, except that a charge blocking layer is provided between the conductive support and the undercoat layer. Were prepared in the same manner as in [Photoconductor Production Example 12]. The film thickness of the obtained charge blocking layer was 0.75 μm.

(2) Examples and Comparative Examples Hereinafter, the effects of the present invention will be shown by Examples and Comparative Examples.
[Example 1]
The electrophotographic photosensitive member 1 produced as described above is mounted on an Imagio Neo 271 electrophotographic copying machine manufactured by Ricoh, and a paper passing durability test is performed in an environment of 23 ° C./55% RH. Images after endurance of 290,000, 310,000 sheets and 330,000 sheets were evaluated. Details are as follows. The charging potential of the photosensitive member was set to −900 V in the dark part potential.
When the paper was passed, a full color printing operation was performed on a character image with a printing rate of 6% on A4 paper, and 330,000 images were output. Then, at the start of the durability test and after the completion of 250,000, 290,000, 310,000 sheets, and 330,000 sheets, three samples for image evaluation (all white) and three samples for potential evaluation (all black) were output.

1) Background stain The background stain on all white images was evaluated after printing 250,000, 290,000, 310,000 sheets and 330,000 sheets. The background stain was judged visually from the third sheet of all white, and graded as follows to obtain measured values. Of these, grades A to C are at a level with no particular problem in image quality.
A: No dirt is recognized B: Very little dirt is observed C: Slight dirt is recognized D: Slight dirt is clearly recognized E: High dirt is recognized F: Very little dirt is recognized Be

2) Bright part potential The bright part potential was expressed by the surface potential of the photoconductor corresponding to the third sheet of all black.

[Examples 2 to 9, 10 to 19, 20]
Evaluation was performed in the same manner as in Example 1 except that the photosensitive members 2 to 9, 11 to 20, and 22 were used as the electrophotographic photosensitive member.

[Comparative Examples 1 and 2]
Evaluation was performed in the same manner as in Example 1 except that the photoreceptors 10 and 21 were used as the electrophotographic photoreceptor.

  The results based on the evaluation level are summarized in Table 1 and Table 2.

In this example, by including a compound having a hydroxyl group and a linear alkyl skeleton having an appropriate range of length in the undercoat layer, the occurrence of scumming is suppressed for a long time, and a high-quality image with a high density is obtained. was gotten.

[Examples 2-5, 11-15]
The same evaluation as in Example 1 was performed except that the photosensitive members 2 to 5 and 12 to 16 were used as the photosensitive member. As a result, as shown in Table 1, a high-quality image with a small degree of background contamination was obtained. Further, as shown in Table 2, there was no problem with the bright part potential.

[Examples 6 to 9, 16 to 19]
The same evaluation as in Example 1 was performed except that the photosensitive members 6 to 9 and 17 to 20 were used as the photosensitive member. As shown in Tables 1 and 2, the results were generally inferior to those of Example 1, but generally good results were obtained.

[Comparative Examples 1 and 2]
The same evaluation as in Example 1 was performed except that the photoconductors 10 and 21 were used as the photoconductor. As shown in Tables 1 and 2, the results were not obtained because a specific alcohol compound in the present invention was not used.

[Examples 10 and 20]
The same evaluation as in Example 1 was performed except that the photoconductors 11 and 22 were used as the photoconductor. As a result, as shown in Tables 1 and 2, a high-quality image with a small degree of background contamination was obtained. Also, there was no problem with the bright part potential.

Schematic cross-sectional view of a photoreceptor according to an embodiment Schematic cross-sectional view of a photoreceptor according to an embodiment Schematic cross-sectional view of a photoreceptor according to an embodiment Schematic cross-sectional view of a photoreceptor according to an embodiment Schematic cross-sectional view of a photoreceptor according to an embodiment Schematic cross-sectional view of a photoreceptor according to an embodiment 1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment. Schematic sectional view of a process cartridge according to an embodiment X-ray diffraction spectrum of single titanyl phthalocyanine It is a model figure which shows the dispersion state of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Photoconductor 2 ... Static elimination lamp 3 ... Charge charger 5 ... Image exposure part 6 ... Developing unit 7 ... Pre-transfer charger 9 ... Transfer body 10 ... Transfer charger 11 ... Separation charger 12 ... Separation claw 13 ... Pre-cleaning charger 14 ... Fur Brush 15 ... Cleaning blade

51 ... conductive support 52 ... charge blocking layer 53 ... undercoat layer 54 ... charge generation layer 55 ... charge transport layer 56 ... photosensitive layer 57 ... protective layer

DESCRIPTION OF SYMBOLS 101 ... Photoconductor 102 ... Charging means 103 ... Exposure 104 ... Developing means
105 ... transfer body 106 ... transfer means 107 ... cleaning means

Claims (21)

A conductive support, an undercoat layer provided on the conductive support, and a photosensitive layer provided on the undercoat layer,
The undercoat layer includes a compound having at least a hydroxyl group and a linear alkyl skeleton, a crosslinkable resin, and hydrophilic fine particles.
An electrophotographic photosensitive member characterized by the above. The compound having a hydroxyl group and a linear alkyl skeleton is represented by the following general formula (1).
The electrophotographic photosensitive member according to claim 1.

However, R represents a linear alkyl skeleton. The linear alkyl skeleton R has 6 or more and 15 or less carbon atoms,
The electrophotographic photosensitive member according to claim 1, wherein the electrophotographic photosensitive member is provided. The crosslinkable resin is a water-soluble resin, an alcohol-soluble resin, a curable resin that forms a three-dimensional network structure,
The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the electrophotographic photosensitive member is provided. The crosslinkable resin is an alkyd resin and / or a melamine resin.
The electrophotographic photosensitive member according to any one of claims 1 to 4, wherein The hydrophilic fine particles are inorganic fine particles (P1).
The electrophotographic photosensitive member according to any one of claims 1 to 5, wherein The inorganic fine particles (P1) are at least one selected from zinc oxide, tin oxide, and titanium oxide.
The electrophotographic photosensitive member according to claim 6. A charge blocking layer is provided between the conductive support and the undercoat layer.
The electrophotographic photosensitive member according to any one of claims 1 to 7, wherein The charge blocking layer comprises at least N-alkoxymethylated nylon;
The electrophotographic photosensitive member according to claim 8. Having a protective layer on the photosensitive layer;
The electrophotographic photosensitive member according to claim 1, wherein The protective layer contains at least inorganic fine particles (P2).
The electrophotographic photosensitive member according to claim 10. The inorganic fine particles (P2) are at least one selected from aluminum oxide, silicon oxide, and titanium oxide.
The electrophotographic photosensitive member according to claim 11. The protective layer is a crosslinked protective layer 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.
The electrophotographic photosensitive member according to claim 10. The functional group of the tri- or higher functional radical polymerizable monomer not having a charge transporting structure used in the protective layer is an acryloyloxy group and / or a methacryloyloxy group.
The electrophotographic photosensitive member according to claim 13. The functional group of the radical polymerizable compound having a charge transporting structure used in the protective layer is an acryloyloxy group or a methacryloyloxy group.
The electrophotographic photosensitive member according to claim 13 or 14, The charge transport structure of the radical polymerizable compound having a charge transport structure used in the protective layer is a triarylamine structure.
The electrophotographic photosensitive member according to any one of claims 13 to 15, wherein The radical polymerizable compound having a charge transporting structure used for the protective layer is one or more of the following general formula (2) or (3).
The electrophotographic photosensitive member according to any one of claims 13 to 16, wherein the electrophotographic photosensitive member is any one of the above items.

(In the formula, R1 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, or a nitro group. , An alkoxy group, —COOR7 (R7 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), a carbonyl halide group Or CONR8R9 (R8 and R9 are a hydrogen atom, a halogen 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; Ar1 and Ar2 represent a substituted or unsubstituted arylene group, and may be the same or different.Ar3 and Ar4 may be substituted or unsubstituted. 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, sulfur An atom and a vinylene group, Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether divalent group, and an alkyleneoxycarbonyl divalent group, m and n represent an integer of 0 to 3.) The radical polymerizable compound having a charge transporting structure used in the protective layer is one or more of the following general formula (4).
The electrophotographic photosensitive member according to claim 17.

(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. ) The electrophotographic photoreceptor according to any one of claims 1 to 18,
An image forming apparatus. The at least one unit selected from the group consisting of a charging unit, an exposure unit, a developing unit, a transfer unit, and a cleaning unit and the electrophotographic photosensitive member according to any one of claims 1 to 18 are integrally held. The image forming apparatus main body has a detachable structure.
A process cartridge characterized by that. Use of the electrophotographic photosensitive member according to any one of claims 1 to 18.
An image forming method.

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