JP2016126040A - Electrophotographic photoreceptor and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor good in cleaning property over a long period and excellent in durability and an electrophotographic device using such electrophotographic photoreceptor.SOLUTION: An electrophotographic photoreceptor includes: at least a charge generating layer, a charge transport layer; and a protection layer on a conductive support in this order. The protection layer includes: a photocurable resin; and a metal oxide subjected to surface processing with a silane coupling agent. The metal oxide contains tin oxide, zinc oxide, or titanium oxide. The silane coupling agent is a graft polymer containing at least one of the silane coupling agent coupled with a metal oxide portion in its side chain, a photoreactivity portion, and a lubricity portion containing at least one of fluorine and silicon.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrophotographic photosensitive member and an electrophotographic apparatus.

  In recent years, organic photoconductors using organic substances have been widely used for electrophotographic photoconductors because the manufacturing cost can be reduced compared to inorganic photoconductors such as amorphous silicon.

  Various electrical and mechanical stresses are applied to the surface layer of the organic photoreceptor due to charging, toner adhesion, transfer, and cleaning processes. When those stresses are applied to the surface layer of the organic photoreceptor, the image quality is deteriorated. Therefore, a photoreceptor having excellent durability is required.

  In order to remove toner, paper dust, and hydrophilic substances generated by the charging process, which adhere to the surface of the photoreceptor, a cleaning method in which a urethane rubber cleaning blade is brought into contact with the photoreceptor surface is generally used.

  However, when the frictional resistance on the surface of the photoconductor is large, phenomena such as reversal of the cleaning blade and squeal of the blade occur. In addition, the cleaning blade is gradually damaged, and toner may pass through the cleaning blade to cause image defects due to poor cleaning. For this reason, suppressing the frictional resistance on the surface of the photoreceptor and improving the cleaning property are important for obtaining a stable image over a long period of time.

  On the other hand, from the viewpoint of printing durability, there are examples in which a protective layer is provided on the surface of the photoconductor to improve the mechanical properties of the photoconductor, and the protective layer contains a curable resin or a filler. For example, in Patent Document 1, a protective layer containing a curable resin is provided on the surface of a photoreceptor. In Patent Document 2, the protective layer further contains a filler. In Patent Document 3, an attempt is made to further improve the mechanical strength of the protective layer by applying a surface treatment to the filler so as to have a crosslinked structure with the surrounding resin.

  However, it is difficult to obtain a photoconductor that achieves all of the printing durability, cleaning property, and scratch resistance by simply increasing the mechanical strength. In order to improve the frictional resistance on the surface of the photoreceptor, there is an example in which fluororesin particles are added to the protective layer to improve the surface lubricity.

  In Patent Documents 4 and 5, fluororesin particles are added to the protective layer. However, even with such a protective layer, it is difficult to maintain good cleaning properties over a long period of time.

  Attempts have also been made to add a lubricant such as silicone oil to the protective layer. In Patent Document 6, silicone oil is added to the protective layer. However, such a lubricant often segregates on the surface, and the effect is lost as the surface of the photoreceptor is shaved.

  In Patent Document 7, silicone oil having a functional group is added to the protective layer in order to suppress surface segregation of the lubricant. However, even when a silicone oil having a structure as described in this patent document is used, it is difficult to suppress surface segregation and is insufficient to maintain good cleaning properties over a long period of time.

Japanese Patent No. 3262488 JP 2008-261971 A JP 11-95473 A JP-A-63-73267 JP 2006-38919 A JP 2005-107490 A JP 2011-170129 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor excellent in durability with good cleaning properties for a long period of time, and an electrophotographic apparatus using such an electrophotographic photoreceptor.

  As a result of earnest research to achieve the above-mentioned object, the present inventor surface-treated the metal oxide with a silane coupling agent having a photoreactive site and a lubricating site in the side chain, and the surface-treated metal oxide It was found that by curing a product together with a photocurable resin and using the cured film as a surface layer of the photoreceptor, the lubricity is maintained even when the surface of the photoreceptor is scraped, and the cleaning property can be maintained.

  This invention is made | formed based on such knowledge, and has the following structures.

(Configuration 1)
In an electrophotographic photosensitive member provided with at least a charge generation layer, a charge transport layer, and a protective layer in this order on a conductive support,
The protective layer includes a photocurable resin and a metal oxide surface-treated with a silane coupling agent,
The metal oxide includes tin oxide, zinc oxide or titanium oxide,
The silane coupling agent is a graft polymer having a silane coupling site bonded to the metal oxide, a photoreactive site, and a lubricating site containing at least one of fluorine and silicon in the side chain. Electrophotographic photoreceptor.

(Configuration 2)
The electrophotographic photosensitive member according to Configuration 1, wherein the silane coupling agent is a graft polymer having an acrylic main chain.

式中、Ｒ_１はアルコキシ基であり、ａは０〜２の整数である。 (Configuration 3)
The electrophotographic photosensitive member according to Configuration 1 or 2, wherein the silane coupling site includes a site represented by General Formula (1).

In the formula, R ₁ is an alkoxy group, and a is an integer of 0-2.

(Configuration 4)
The electrophotographic photosensitive member according to Configuration 3, wherein R ₁ is a methoxy group, and a is 0.

式中、Ｒ_２はアルキル基であり、Ｙは光反応性官能基である。 (Configuration 5)
5. The electrophotographic photosensitive member according to any one of configurations 1 to 4, wherein the photoreactive site includes a site represented by the general formula (2).

In the formula, R ₂ is an alkyl group, and Y is a photoreactive functional group.

(Configuration 6)
The electrophotographic photoreceptor according to Configuration 5, wherein Y is an acryloyl group or a methacryloyl group.

式中、Ｘ_１はアルキル基であり、Ｘ_２およびＸ_３はそれぞれアルキル基またはアリール基であり、ｎ_１およびｎ_２はそれぞれ１〜５００の整数である。 (Configuration 7)
The electrophotographic photosensitive member according to any one of configurations 1 to 6, wherein the lubricious portion includes a portion represented by the general formula (3).

In the formula, X ₁ is an alkyl group, X ₂ and X ₃ are each an alkyl group or an aryl group, and n ₁ and n ₂ are each an integer of _{1 to} 500.

式中、ｍは１〜４００の整数である。 (Configuration 8)
The electrophotographic photosensitive member according to any one of Configurations 1 to 6, wherein the lubricious portion includes a portion represented by the general formula (4).

In the formula, m is an integer of 1 to 400.

(Configuration 9)
The electrophotographic photosensitive member according to any one of configurations 1 to 8, wherein the silane coupling agent has a weight average molecular weight of 300 to 100,000.

(Configuration 10)
The electrophotographic photosensitive member according to any one of configurations 1 to 9, wherein the metal oxide has an average primary particle size of 5 nm to 300 nm.

(Configuration 11)
The electrophotographic photosensitive member according to any one of configurations 1 to 9, wherein the metal oxide has an aspect ratio of 3 or more.

(Configuration 12)
The said photocurable resin is an acrylic resin formed from the at least 1 sort (s) of starting material selected from the group which consists of an acrylic monomer, an oligomer, and a dendrimer, The structure any one of the structures 1-11 Electrophotographic photoreceptor.

(Configuration 13)
The electrophotographic photosensitive member according to any one of configurations 1 to 12, wherein the charge generation layer contains at least one of oxotitanyl phthalocyanine and gallium phthalocyanine.

(Configuration 14)
The electrophotographic photosensitive member according to any one of Structures 1 to 13, a charging unit for charging the electrophotographic photosensitive member, and exposing the charged electrophotographic photosensitive member to expose the electrophotographic photosensitive member on the electrophotographic photosensitive member. An image exposing means for forming an electrostatic latent image on the surface, a developing means for developing the electrostatic latent image formed on the electrophotographic photosensitive member with toner to form a toner image, and transferring the toner image to a transfer material. An electrophotographic apparatus comprising: cleaning means for removing toner remaining on the electrophotographic photosensitive member after being processed.

  In the present invention, a metal oxide surface-treated with a silane coupling agent having a side chain having a silane coupling site, a lubrication site, and a photoreactive site capable of binding to a metal oxide on a protective layer of an electrophotographic photoreceptor. Since the product and the photocurable resin are included, the photoreactive site of the silane coupling agent bonded to the metal oxide via the silane coupling site can be crosslinked with the photocurable resin. For this reason, the silane coupling agent is easily dispersed uniformly in the protective layer, and as a result, the lubricated portion of the silane coupling agent is also uniformly dispersed in the protective layer. Even if the protective layer is shaved, the lubricity is hardly lost and the cleaning property can be maintained. Thus, according to the present invention, it is possible to provide an electrophotographic photosensitive member having excellent durability and excellent durability and an electrophotographic apparatus using such an electrophotographic photosensitive member. .

1 is a schematic cross-sectional view of an electrophotographic photosensitive member according to an embodiment of the present invention. It is a cross-sectional schematic diagram of the protective layer of the electrophotographic photosensitive member shown in FIG. It is a figure which shows the typical structure of the silane coupling agent concerning one Embodiment of this invention. It is a figure which shows an example of the molecular structure of a silicon-type silane coupling agent. It is a figure which shows an example of the molecular structure of a fluorine-type silane coupling agent. It is a figure which shows the polymerization reaction in preparation of the silicon-type silane coupling agent of FIG. 1 is a schematic diagram of an electrophotographic apparatus according to an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functions and configurations are denoted by the same reference numerals, and redundant description is omitted.

<Electrophotographic photoreceptor>
FIG. 1 shows a schematic cross-sectional view of an electrophotographic photosensitive member according to an embodiment of the present invention. The electrophotographic photoreceptor 1 includes at least a charge generation layer 3 on a conductive support 2, a charge transport layer 4 on the charge generation layer 3, and a protective layer 5 on the charge transport layer 4.

(Conductive support)
The conductive support may be anything as long as it has conductivity, for example, a metal such as aluminum, copper, chromium, nickel, zinc and stainless steel formed into a drum, sheet or belt, aluminum Metal foil such as copper and copper laminated on plastic film, aluminum, indium oxide and tin oxide deposited on plastic film, metal, plastic film and paper etc. with conductive material applied alone or with binder resin Examples include a conductive layer.

(Charge generation layer)
The charge generation layer is a layer mainly composed of a charge generation material having a charge generation function, and may contain a binder resin as necessary. A known charge generation material can be used for the charge generation layer. Examples of the charge generating substance include a monoazo pigment, a disazo pigment, an asymmetric disazo pigment, a trisazo pigment, an azo pigment having a carbazole skeleton, an azo pigment having a distyrylbenzene skeleton, an azo pigment having a triphenylamine skeleton, and a diphenylamine skeleton. Examples thereof include azo pigments, perylene pigments, and phthalocyanine pigments. These charge generation materials may be used alone or in combination of two or more. Among them, the charge generation layer preferably contains at least one of oxotitanyl phthalocyanine and gallium phthalocyanine because good electrical characteristics can be obtained.

  Examples of the binder resin used for the charge generation layer as needed include polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, and polyvinyl ketone. These binder resins can be used alone or as a mixture of two or more.

  The charge generation material is dispersed in a solvent using a known dispersion method such as ball mill, attritor, sand mill, bead mill, and ultrasonic wave together with a binder resin as necessary, and the charge generation layer is applied to the conductive support. The coating liquid for this can be obtained.

  The film thickness of the charge generation layer is preferably from 0.01 to 5 μm, more preferably from 0.05 to 3 μm.

(Charge transport layer)
The charge transport layer is a layer having a charge transport structure, and is a layer mainly composed of a charge transport material and a binder resin. The charge transport layer contains a hole transport material as a charge transport material, but may contain an electron transport material as necessary.

  Examples of hole transport materials include poly (N-vinylcarbazole) and derivatives thereof, poly (γ-carbazolylethyl glutamate) and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, and oxazole derivatives. Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, aminobiphenyl derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9- Styryl anthracene derivative, pyrazoline derivative, divinylbenzene derivative, hydrazone derivative, indene derivative, butadiene derivative, pyrene derivative, bis-stilbene derivative Materials, distyrylbenzene derivatives, enamine derivatives and the like. These hole transport materials can be used alone or as a mixture of two or more.

  Binder resins include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polycarbonate. Examples thereof include thermoplastic or thermosetting resins such as resins and polyarylate resins.

  Examples of the electron transporting material include electron accepting materials such as chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, and 7-trinitro-9-fluorenone. These electron transport materials can be used alone or as a mixture of two or more.

  A coating liquid for applying the charge transport layer to the conductive support can be obtained by dissolving the charge transport material and the binder resin in a solvent.

  The thickness of the charge transport layer is preferably 5 to 40 μm, more preferably 10 to 35 μm.

(Protective layer)
FIG. 2 shows a schematic sectional view of a protective layer according to an embodiment of the present invention. The protective layer 5 contains at least a photocurable resin 51 and a metal oxide 52 that is dispersed in the photocurable resin 51 and is surface-treated with a silane coupling agent.

Photocurable resin Examples of the photocurable resin include acrylic resins, epoxy resins, oxetane resins, and the like. A photo-curable copolymer resin can also be used. The acrylic resin can be formed from at least one starting material selected from the group consisting of acrylic monomers, oligomers, and dendrimers. Since the dendrimer has a spherical structure in which the inside is dense and the outside is sparse, when used as a starting material, flexibility can be maintained while maintaining hardness. Thereby, the scratch resistance of the protective layer and the like can be improved, and the brittleness of the film can be improved. When a dendrimer is added to at least one of acrylic monomers and oligomers, high Martens hardness can be obtained and printing durability can be improved. Each of the acrylic monomer, oligomer, and dendrimer preferably has three or more acryloyl groups or methacryloyl groups, that is, has a trifunctional or higher radical polymerization property. Examples of acrylic monomers include ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, and trimethylolpropane triacrylate. As the acrylic oligomer, those having a number average molecular weight of 170 to 2000 can be used, and examples thereof include a urethane acrylate oligomer, an epoxy acrylate oligomer, and a polyester acrylate oligomer. As an acrylic dendrimer, what has a single molecular weight peak in the range of a weight average molecular weight 1000 or more and 25000 or less can be used. The acrylic dendrimer is preferably made of either polyester acrylate or copolymer polyacrylate. The copolymer polyacrylate is preferably a crosslinkable polymer having two or more epoxy groups as reactive groups in the molecule. For example, polyacrylate copolymerized with glycidyl acrylate is preferable. Epoxy resins include 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, 1,2,8,9-diepoxylimonene, bis (3,4-epoxycyclohexylmethyl) adipate, etc. Can be formed from starting materials.

-Silane coupling agent The typical structure of the silane coupling agent 6 concerning one Embodiment of this invention is shown in FIG. The silane coupling agent 6 has a silane coupling part 61, a photoreactive part 62, and a lubricating part 63. The silane coupling site 61 can be bonded to the metal oxide 7, and the photoreactive site 62 can be bonded to the photocurable resin 51. More specifically, the silane coupling agent of the present invention has a silane coupling site bonded to a metal oxide, a photoreactive site, and a lubricating site containing at least one of fluorine and silicon in the side chain. It is a graft polymer.

  The graft polymer can have a main chain such as acrylic, epoxy, or oxetane. When an acrylic resin is used as the photocurable resin, a graft polymer having an acrylic main chain is preferable, and when an epoxy resin is used as the photocurable resin, a graft polymer having an epoxy main chain is used. Coalescence is preferred. In this specification, the acrylic main chain indicates a skeleton structure in which acryloyl groups or methacryloyl groups are polymerized. The epoxy main chain means a skeleton structure in which epoxy groups are polymerized. Among them, a graft polymer having an acrylic main chain is particularly preferable because the reaction rate when the main chain is formed is increased.

式中、Ｒ_１はアルコキシ基であり、ａは０〜２の整数である。アルコキシ基としては、炭素数が１〜５のものを挙げることができ、より具体的にはメトキシ基およびエトキシ基を挙げることができる。 The silane coupling site can include a site represented by the general formula (1).

In the formula, R ₁ is an alkoxy group, and a is an integer of 0-2. As an alkoxy group, a C1-C5 thing can be mentioned, More specifically, a methoxy group and an ethoxy group can be mentioned.

In general formula (1), R ₁ is preferably a methoxy group and a is preferably 0. A silane coupling site containing a trimethoxysilyl group has an advantage of being easily bonded to a metal oxide. The site represented by the general formula (1) can be bonded to the acrylic main chain via an alkyl group, and such an alkyl group can have 1 to 5 carbon atoms. In FIGS. 4 and 5 to be described later, as such an alkyl group, a propyl group located between the —COO group of the main chain and the trimethoxysilyl group is exemplified.

式中、Ｒ_２はアルキル基であり、Ｙは光反応性官能基である。Ｒ_２のアルキル基としては、炭素数が１〜５のもの、具体的にはエチル基を挙げることができる。一般式（２）で示される部位は、アルキル基を介してアクリル系の主鎖に結合することができ、そのようなアルキル基は炭素数１〜５とすることができる。後述する図４、５では、そのようなアルキル基として、主鎖の−ＣＯＯ基と、ＮＨ基に隣接する−ＣＯＯ基との間に位置するエチル基が例示されている。 The photoreactive site has a photoreactive functional group, and can particularly include a site represented by the general formula (2).

In the formula, R ₂ is an alkyl group, and Y is a photoreactive functional group. Examples of the alkyl group for R ₂ include those having 1 to 5 carbon atoms, specifically, an ethyl group. The site represented by the general formula (2) can be bonded to the acrylic main chain via an alkyl group, and such an alkyl group can have 1 to 5 carbon atoms. In FIGS. 4 and 5 to be described later, as such an alkyl group, an ethyl group located between the —COO group of the main chain and the —COO group adjacent to the NH group is exemplified.

Examples of the photoreactive functional group include an acrylic functional group, an epoxy group, and an oxetane group. When an acrylic resin is used as the photocurable resin, an acrylic photoreactive functional group is preferable. When an epoxy resin is used as the photocurable resin, the photoreactive functional group is an epoxy group. Is preferred. By combining in this way, the photoreactive functional group is easily crosslinked with the photocurable resin. Examples of the acrylic photoreactive functional group include an acryloyl group (CH ₂ CHCOO—) and a methacryloyl group (CH ₂ C (CH ₃ ) COO—).

式中、Ｘ_１はアルキル基であり、Ｘ_２およびＸ_３はそれぞれアルキル基またはアリール基である。ｎ_１およびｎ_２はそれぞれ１〜５００の整数であり、例えば１〜３００の範囲、より具体的には１０〜２００の範囲とすることができる。Ｘ_１のアルキル基は、例えば、炭素数が１〜３のものである。Ｘ_２およびＸ_３のアルキル基はそれぞれ、例えば、炭素数が１〜３のものであり、また、アリール基としては、フェニル基、ベンジル基等を挙げることができる。潤滑性に優れることから、Ｘ_１、Ｘ_２、Ｘ_３ともにメチル基であるか、またはＸ_１がメチル基で、Ｘ_２およびＸ_３がフェニル基であるか、またはＸ_１およびＸ_２がメチル基で、Ｘ_３がフェニル基であることが好ましい。これらは感光体の電気特性を損なわない点でも好ましい。Ｘ_１、Ｘ_２、Ｘ_３ともにメチル基であるものを、ジメチルシリコーンタイプと称することができる。Ｘ_１がメチル基で、Ｘ_２およびＸ_３がフェニル基であるか、またはＸ_１およびＸ_２がメチル基で、Ｘ_３がフェニル基であるものを、メチルフェニルシリコーンタイプと称することができる。一般式（３）で示される部位は、アルキル基を介してアクリル系の主鎖に結合することができ、そのようなアルキル基は、後述する図４ではＲ_３で示されており、炭素数１〜５とすることができる。また、ケイ素を含む潤滑性部位の末端基としては、メチル基、ｔｅｒｔ−ブチル基等を挙げることができる。ケイ素を含む潤滑性部位の末端基は図４ではＲ_４で示されている。 The lubricious site includes at least one of silicon and fluorine. In the case of containing silicon, the lubrication site can include a site represented by the general formula (3).

In the formula, X ₁ is an alkyl group, and X ₂ and X ₃ are each an alkyl group or an aryl group. Each of n ₁ and n ₂ is an integer of _{1 to} 500, and can be, for example, in the range of 1 to 300, more specifically in the range of 10 to 200. The alkyl group for X ₁ is, for example, one having 1 to 3 carbon atoms. Each of the alkyl groups represented by X ₂ and X ₃ has, for example, one having 1 to 3 carbon atoms, and examples of the aryl group include a phenyl group and a benzyl group. Since X ₁ , X ₂ , and X ₃ are all methyl groups, or X ₁ is a methyl group, X ₂ and X ₃ are phenyl groups, or X ₁ and X ₂ are methyl groups because of excellent lubricity In the group, X ₃ is preferably a phenyl group. These are also preferable in that they do not impair the electrical characteristics of the photoreceptor. Those in which all of X ₁ , X ₂ and X ₃ are methyl groups can be referred to as dimethyl silicone type. A compound in which X ₁ is a methyl group, X ₂ and X ₃ are phenyl groups, or X ₁ and X ₂ are methyl groups and X ₃ is a phenyl group can be referred to as a methylphenyl silicone type. The site represented by the general formula (3) can be bonded to the acrylic main chain via an alkyl group, and such an alkyl group is represented by R ₃ in FIG. 1-5. Further, examples of the terminal group of the lubricating site containing silicon include a methyl group and a tert-butyl group. The end group of the lubricious site containing silicon is indicated by R ₄ in FIG.

式中、ｍは１〜４００の整数であり、例えば１〜１００の範囲、より具体的に１〜２０の範囲とすることができる。一般式（４）で示される部位を潤滑性部位に含むものは、感光体の電気特性を損なわないと考えられる。潤滑性部位が繰り返し単位として−ＣＦ_２−ＣＦ_２−を含むものを、ポリテトラフルオロエチレン（ＰＴＦＥ）タイプと称することができる。一般式（４）で示される部位は、アルキル基を介してアクリル系の主鎖に結合することができ、そのようなアルキル基は、後述する図５ではＲ_５で示されており、炭素数１〜５とすることができる。また、フッ素を含む潤滑性部位の末端基としては、Ｆ−（フルオロ基）、Ｈ−等を挙げることができる。フッ素を含む潤滑性部位の末端基は図５ではＲ_６で示されている。フッ素を含む潤滑性部位としては、前述したものの他にも、パーフルオロポリエーテル構造、ポリクロロトリフルオロエチレン構造等を含むものを挙げることもできる。 When the lubricating part contains fluorine, the lubricating part can contain a part represented by the general formula (4).

In the formula, m is an integer of 1 to 400, and can be, for example, in the range of 1 to 100, more specifically in the range of 1 to 20. Those containing the site represented by the general formula (4) in the lubrication site are considered not to impair the electrical characteristics of the photoreceptor. A lubricating part containing —CF ₂ —CF ₂ — as a repeating unit can be referred to as a polytetrafluoroethylene (PTFE) type. The site represented by the general formula (4) can be bonded to the acrylic main chain via an alkyl group, and such an alkyl group is represented by R ₅ in FIG. 1-5. Further, examples of the terminal group of the lubricating site containing fluorine include F- (fluoro group) and H-. The end group of the lubricating site containing fluorine is indicated by R ₆ in FIG. Examples of the lubricating part containing fluorine include those containing a perfluoropolyether structure, a polychlorotrifluoroethylene structure, and the like in addition to those described above.

  The silane coupling agent can have a weight average molecular weight of 300 or more and less than 120,000, preferably 300 to 100,000, more preferably 5,000 to 20,000. If the weight average molecular weight is too large, the viscosity becomes high and there is a risk of adverse effects during coating. Moreover, there exists a possibility of inhibiting the hardening of photocurable resin. If the weight average molecular weight is too small, the lubricity portion tends to be shortened, so that the lubricity effect is hardly exhibited. Further, the entanglement with the photo-curing resin becomes insufficient, and there is a possibility that bleeding on the surface of the photoreceptor occurs. The polydispersity of the silane coupling agent can be 1-5.

FIG. 4 shows an example of the molecular structure of a silane coupling agent containing silicon at the lubricating site, and FIG. 5 shows an example of the molecular structure of a silane coupling agent containing fluorine at the lubricating site. The silane coupling agent shown in FIG. 4 is a silane coupling agent having an acrylic main chain containing a dimethylsilicone type lubricating site, a photoreactive site containing an acrylic photoreactive functional group, and a trimethoxysilyl group. It is a graft polymer in which each part extends as a side chain. In FIG. 4, n indicates a value of n ₁ + n ₂ . The silane coupling agent shown in FIG. 5 has an acrylic main chain, a PTFE-type lubrication site, a photoreactive site containing an acrylic photoreactive functional group, and a silane coupling site containing a trimethoxysilyl group. Are graft polymers each extending as a side chain. In FIG. 5, r represents an integer of 1 to 200. In FIGS. 4 and 5, the silane coupling site, the photoreactive site, and the lubricating site are arranged in this order. However, the order is not limited to this, and the arrangement order may be changed. Or a silane coupling site | part, a photoreactive site | part, and a lubricous site | part may connect at random. Moreover, each of a silane coupling site | part, a photoreactive site | part, and a lubricous site | part may continue.

  Since the silane coupling agent of the present invention has a photoreactive site that can be cross-linked with a photocurable resin together with a lubricating site, it is easily dispersed uniformly in the protective layer and hardly segregates on the surface. For this reason, even if the surface of the photoreceptor is scraped, the lubricity is maintained and the cleaning property can be maintained. Moreover, not only the mechanical strength is maintained by crosslinking with the photocurable resin, but also the packing property for protecting the lower layer of the protective layer from acid gas and humidity can be maintained. In addition, since it has a photoreactive site and a silane coupling site in the side chain, the number of each site per molecule can be increased, and it can be cross-linked more strongly with the photocurable resin, or by metal oxide. It can be coupled firmly.

・ Metal oxides Metal oxides are tin oxides doped with tin oxide, zinc oxide, titanium oxide, alumina, zirconia, indium oxide, antimony oxide, bismuth oxide, calcium oxide, antimony, from the viewpoint of improving wear resistance. Phosphorus-doped tin oxide, tin-doped indium oxide, and the like can be included. A certain metal oxide and another metal oxide may be contained in the protective layer. It is preferable that the metal oxide contains any of tin oxide, zinc oxide, and titanium oxide because it has a resistance value suitable for hole transport and is effective in suppressing increase in residual potential.

  The metal oxide preferably has an average primary particle size of 5 nm to 300 nm. This average primary particle size is calculated by observation with a scanning electron microscope and image analysis. If the particle size of the metal oxide is too large, the image quality may be deteriorated, and a wide linear scratch may occur on the surface of the photoreceptor. If the particle size of the metal oxide is too small, the cohesiveness becomes high and there is a risk of causing a decrease in wear resistance. The metal oxide can have an aspect ratio of 3 or greater. A metal oxide having an aspect ratio of 3 or more can take a needle-like form. If the aspect ratio is too large, the dispersibility may be lowered or the coatability may be deteriorated. Therefore, the aspect ratio can be 50 or less.

  The weight ratio of the metal oxide surface-treated with the silane coupling agent and the photocurable resin [metal oxide surface-treated with the silane coupling agent]: [photocurable resin] is 1: 100 to 100: The range may be 100, and more specifically, the range may be 5: 100 to 80: 100. If the amount of the metal oxide with respect to the photocurable resin is too large, there is a possibility that the chargeability is lowered, image defects such as black spots, and image flow occur. On the other hand, if the amount of the metal oxide relative to the photocurable resin is too small, good sensitivity characteristics may not be obtained.

  Hereinafter, a method for preparing a silane coupling agent and a surface treatment method for a metal oxide according to an embodiment will be described with reference to FIG.

  First, a surface treatment agent for applying a surface treatment to a metal oxide is prepared. An acrylate or methacrylate having a silane coupling site, an isocyanate having a photoreactive site, an acrylate or methacrylate having a urethane-bondable functional group, an acrylate or methacrylate having a lubrication site, and a polymerization initiator as necessary. Is polymerized in an inert gas atmosphere in the presence of a solvent (in FIG. 6, the first stage of the polymerization reaction). Thereafter, an isocyanate having a photoreactive site is added, and a polymerization reaction is performed in the presence of a catalyst (in FIG. 6, the second stage of the polymerization reaction). Thereby, the surface treating agent containing the silane coupling agent which has an acrylic main chain is obtained. The reaction conditions for the first stage of the polymerization reaction can be 1 to 12 hours at 40 to 120 ° C.

重合開始剤としては、アゾビスイソブチロニトリル（ＡＩＢＮ）、２，２’−アゾビス−２−メチルブチロニトリル（ＡＭＢＮ）、２，２’−アゾビス−２，４−ジメチルバレロニトリル（ＡＤＶＮ）等を挙げることができる。溶媒としては、ジエチレングリコールエチルメチルエーテル、ジメチルスルホキシド、トルエン等を挙げることができる。光反応性部位を有するイソシアネートとしては、２−イソシアナトエチルメタクリレート、２−イソシアナトエチルアクリラート等を挙げることができる。触媒としては、ジブチルスズジラウレート、ジブチルスズジアセテート、トリフェニルホスフィン等を挙げることができる。 Examples of the acrylate or methacrylate having a silane coupling site include 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyldiethoxysilane, and 3-acryloxypropyltrimethoxysilane. Examples of the acrylate or methacrylate having an isocyanate having a photoreactive site and a functional group capable of urethane bonding include 2-hydroxyethyl methacrylate (HEMA), 4-hydroxybutyl acrylate, and 2-hydroxypropyl methacrylate. As the acrylate or methacrylate having a lubricious site, when the lubricated site contains silicon, an acrylic-modified or methacryl-modified reactive silicone oil or the like can be mentioned. When the lubricated site contains fluorine Examples include octafluoropentyl acrylate and 2,2,2-trifluoroethyl acrylate represented by the structural formula (5).

As polymerization initiators, azobisisobutyronitrile (AIBN), 2,2′-azobis-2-methylbutyronitrile (AMBN), 2,2′-azobis-2,4-dimethylvaleronitrile (ADVN) Etc. Examples of the solvent include diethylene glycol ethyl methyl ether, dimethyl sulfoxide, toluene and the like. Examples of the isocyanate having a photoreactive site include 2-isocyanatoethyl methacrylate and 2-isocyanatoethyl acrylate. Examples of the catalyst include dibutyltin dilaurate, dibutyltin diacetate, and triphenylphosphine.

  By dispersing the obtained surface treatment agent and metal oxide in a dispersion solvent using a sand mill or the like, a solution containing the surface-treated metal oxide can be obtained. Examples of the dispersion solvent include methanol, n-propanol, and mixtures thereof. The obtained solution containing the surface-treated metal oxide can constitute a protective layer coating solution together with the starting material of the photocurable resin and other materials such as a polymerization initiator and a solvent. As the polymerization initiator at this time, various radical photopolymerization initiators such as α-aminoalkylphenone, α-hydroxyalkylphenone, and oxime ester can be used. Similar ones can be used.

  In FIG. 6, 3-methacryloxypropyltrimethoxysilane is used for methacrylate having a silane coupling site, HEMA is used for methacrylate having a functional group capable of urethane-bonding with an isocyanate having a photoreactive site, and having a lubrication site The polymerization reaction is shown when 2-isocyanatoethyl methacrylate is used as an isocyanate having a photoreactive site using a one-end reactive silicone oil that has been methacryl-modified to methacrylate. In the second stage of the polymerization reaction, the hydroxyl group of HEMA and the isocyanate group of isocyanate form a urethane bond.

  In addition, although the preparation method of the silane coupling agent which has an acrylic main chain was demonstrated here, the silane coupling agent which has an epoxy-type main chain, for example, a silane coupling site | part, a photoreactive site | part, lubricity It can be prepared by ring-opening polymerization of an epoxy group using one having a reactive epoxy group as a starting material having each site.

  The protective layer can further contain a charge transport material. By containing the charge transport material in the protective layer, it is possible to reduce the residual potential and suppress the sensitivity deterioration. As the charge transport material used for the protective layer, all the charge transport materials described in the above-mentioned charge transport layer can be used.

  The thickness of the protective layer is preferably from 0.1 to 10 μm, more preferably from 1 to 7 μm.

  A protective layer can be obtained by curing the protective layer coating solution. The protective layer coating liquid is preferably cured by irradiating with actinic radiation to cause radical polymerization to form a cross-linking bond between molecules. As the types of active rays, there are electron beams and ultraviolet rays, but ultraviolet rays are preferable in view of mass productivity. As the irradiation device, a metal halide lamp, a mercury lamp, an ultraviolet LED, or the like can be used.

(Middle layer)
An intermediate layer may be provided between the conductive support and the charge generation layer. The intermediate layer functions as a barrier layer or an adhesive layer that controls charge injection at the interface. The intermediate layer is mainly composed of a binder resin, but may contain a metal, an alloy, or oxides, salts, and surfactants thereof. The binder resin that forms the intermediate layer is polyester, polyurethane, polyarylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, phenol resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd Examples thereof include resins, polyamideimides, polysulfones, polyallyl ethers, polyacetals, and butyral resins. The thickness of the intermediate layer is preferably 0.05 μm to 7 μm, more preferably 0.1 μm to 2 μm.

  The charge generation layer, the charge transport layer and the protective layer, and if necessary, the intermediate layer can be applied to the conductive support by a known coating method. Specific examples include a blade coating method, a dip coating method, and a spray coating method.

  As described above, in the electrophotographic photoreceptor 1 according to the present embodiment, the silane coupling portion 61, the photoreactive portion 62, and the lubricating portion 63 that can be bonded to the metal oxide are side-chained in the protective layer 5. A silane coupling agent bonded to the metal oxide via a silane coupling site because it contains the metal oxide 52 surface-treated with the silane coupling agent 6 which is a graft polymer in the photopolymerizable resin 51 and the photocurable resin 51 These photoreactive sites can be crosslinked with the photocurable resin. For this reason, it becomes easy to disperse | distribute a silane coupling agent uniformly in a protective layer, without segregating on the surface of a protective layer. As a result, the lubricating part of the silane coupling agent is also uniformly dispersed in the protective layer, so even during the use of the electrophotographic photoreceptor, even if the protective layer is gradually scraped, the lubricity is not easily lost and excellent. The cleaning ability can be demonstrated for a long time. Moreover, the strength of the protective layer can also be improved by the crosslinked structure of the photoreactive site and the photocurable resin. In this way, an electrophotographic photoreceptor excellent in durability can be realized.

<Electrophotographic device>
An electrophotographic apparatus of the present invention includes the electrophotographic photosensitive member of the present invention, a charging unit that charges the peripheral surface of the electrophotographic photosensitive member, an image exposing unit, a developing unit, and a cleaning unit. . Hereinafter, a description will be given with reference to FIG.

  FIG. 7 is a schematic diagram of the electrophotographic apparatus 10 according to an embodiment of the present invention. The electrophotographic apparatus 10 includes a semiconductor laser 11 as image exposure means. The laser light signal-modulated by the image information by the control circuit 20 is collimated through the correction optical system 12 after being emitted, and is reflected by the rotary polygon mirror 13 to perform a scanning motion. The laser light is condensed on the surface of the electrophotographic photosensitive member 1 by the f-θ lens 14 to expose image information. Since the electrophotographic photosensitive member 1 is charged in advance by a charging device 15 as a charging unit, an electrostatic latent image is formed on the surface by this exposure. Next, the developing device 16 which is a developing unit develops the electrostatic latent image formed on the electrophotographic photosensitive member 1 with toner to form a toner image, thereby forming a visible image. This visible image is transferred to an image receptor 21 such as paper by the transfer device 17, fixed by the fixing device 19, and provided as a printed matter. The electrophotographic photosensitive member 1 can be used repeatedly by removing toner and toner components remaining on the surface by a cleaning device 18 as a cleaning means.

  The drum-shaped electrophotographic photosensitive member 1 shown in FIG. 7 is driven to rotate at a predetermined peripheral speed around an axis. In the rotation process, the electrophotographic photosensitive member is uniformly charged at a predetermined positive or negative potential on its peripheral surface by the charging means. The applied voltage is, for example, an oscillating voltage obtained by superimposing an AC voltage on a DC voltage. Although the drum-shaped electrophotographic photosensitive member has been described here, a sheet-shaped or belt-shaped electrophotographic photosensitive member can also be used.

  As the charging device 15, a contact charging device that applies a charge by bringing a charging member such as a charging roller or a charging brush into contact with the photosensitive member is used. In addition to the charging device 15 as shown in FIG. 7, a non-contact charging roller, a scorotron charger using a corona discharge, a corotron charger, or the like can be used as the charging means.

  A plurality of components such as an electrophotographic photosensitive member, a charging unit, and a developing unit in an electrophotographic apparatus are integrally combined as a process cartridge, and the process cartridge is a copying machine, a laser beam printer, or the like. It can also be configured to be detachable from the main body of the electrophotographic apparatus.

  As described above, since the electrophotographic apparatus 10 according to this embodiment includes the electrophotographic photosensitive member 1 having excellent durability as described above, the surface of the photosensitive member is gradually scraped during use. The lubricity of the surface is not easily lost, and the cleaning property of the photoconductor is good for a long time. Therefore, the cleaning means is not easily damaged, and not only the photoconductor but also the cleaning means can be used for a longer period of time, so that the life of the electrophotographic apparatus can be extended.

  Hereinafter, based on an Example, this invention is demonstrated more concretely.

[Example 1]
A photoreceptor was prepared by the following procedure.

(Conductive support)
An aluminum base tube having an outer diameter of 30 mm was used as the conductive support.

(Middle layer)
The following materials were dispersed for 5 hours using a bead mill. CM8000 (manufactured by Toray Industries, Inc.) was used as the polyamide resin, and MT-500SA (manufactured by Teika Corporation) was used as the titanium oxide.
Polyamide resin 5 parts by weight Titanium oxide 5 parts by weight Methanol 50 parts by weight n-propanol 10 parts by weight The dispersed liquid was dip-coated on a conductive support to form an intermediate layer having a thickness of 1 μm.

(Charge generation layer)
The following materials were dispersed for 3 hours using a bead mill. BX-5 (manufactured by Sekisui Chemical Co., Ltd.) was used as the butyral resin.
Oxo titanyl phthalocyanine pigment (Y type) 10 parts by weight Butyral resin 10 parts by weight 1,2-dimethoxyethane 900 parts by weight Cyclohexanone 100 parts by weight The dispersed liquid is dip-coated on a conductive support on which an intermediate layer has been formed. A 0.2 μm charge generation layer was formed.

(Charge transport layer)
The following materials were mixed with 100 parts by weight of THF and dissolved. PCZ-500 (Mitsubishi Gas Chemical Co., Ltd.) was used for the polycarbonate.
Charge transport material: 1,1-bis (4-diethylaminophenyl) -4,4-diphenyl-1,3-butadiene 10 parts by weight Binder resin: Polycarbonate 10 parts by weight Antioxidant: BHT 0.1 part by weight Dissolved liquid Was dip-coated on a conductive support having a charge generation layer as described above to form a charge transport layer having a thickness of 20 μm. Thereafter, drying was performed at 135 ° C. for 30 minutes.

(Protective layer)
As component A, 3-methacryloxypropyltrimethoxysilane [Dynasylan MEMO (Evonik)] is used, as component B, 2-hydroxyethyl methacrylate (HEMA) [manufactured by Tokyo Chemical Industry], and as component C, One-end reactive silicone oil [X-22-174DX (manufactured by Shin-Etsu Silicone)] was used. These components were prepared so that the molar ratio of component A: component B: component C was 30:40:30. 5 parts by weight of AIBN was added as an initiator with respect to a total of 100 parts by weight of the three components. Diethylene glycol ethyl methyl ether was added so that the solid content, that is, the total of the three components A to C and AIBN was 15% by weight, and the polymerization reaction was carried out at 70 ° C. for 4 hours with stirring under nitrogen substitution. Liquid 1 was obtained.

  2-isocyanatoethyl methacrylate [Karenz MOI (manufactured by Showa Denko KK)] having the same number of moles as the amount of HEMA charged in the reaction solution 1 was added to 100 parts by weight of the reaction solution 1 thus obtained. Further, 10 parts by weight of dibutyltin dilaurate was added as a catalyst. This was reacted at 65 ° C. with stirring. During this time, in order to confirm the reaction between the hydroxyl group of HEMA and the isocyanate group of 2-isocyanatoethyl methacrylate, the reaction was carried out while confirming the peak reduction of isocyanate by FT-IR. After 6 hours, it was confirmed that the isocyanate peak disappeared, and this liquid was used as reaction liquid 2. The reaction solution 2 was subjected to gel permeation chromatography (GPC) to measure the weight average molecular weight of the obtained silane coupling agent. The results are shown in Table 1. In addition, Table 1 shows the photoreactive site of the obtained silane coupling agent, the main functional groups of the silane coupling site, and the structural type of the lubricating site.

The surface treatment of the metal oxide was performed as follows.
As the metal oxide, antimony-doped tin oxide (hereinafter referred to as ATO) [T-1 (manufactured by Mitsubishi Electronic Material Chemical Co., Ltd.)] was used. Table 1 shows the average primary particle size of the metal oxides used. The average primary particle size was calculated by projecting an enlarged photograph of the particles with a scanning electron microscope (manufactured by JEOL Ltd.) and analyzing the image of the photograph taken with the scanner. In addition, a dispersion solvent in which methanol and n-propanol were mixed at a weight ratio of 7: 3 was used. These materials and the reaction liquid 2 were mixed in the following ratio, and dispersed for 6 hours using a sand mill.
Reaction solution 2 0.1 part by weight Metal oxide 10 parts by weight Dispersion solvent 40 parts by weight The solution thus obtained contains 20% by weight of surface-treated ATO as a solid content. Used as.

A protective layer was formed as follows.
As a polymerization initiator, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one [Irgacure 907 (manufactured by Ciba Japan)] is used, and a urethane acrylate oligomer is used as a photocurable resin. [UV-7605B (manufactured by Nihon Gosei Co., Ltd.)] (weight average molecular weight: 1100, number average molecular weight: 800), and as a dispersion solvent, a mixture of methanol and n-propanol at a weight ratio of 7: 3 Was used. These materials were added in the following ratio with respect to 10 parts by weight of the ATO solution, and mixed and stirred under light shielding to prepare a protective layer coating solution.
Polymerization initiator 0.6 parts by weight Photocurable resin 10 parts by weight Dispersion solvent 42.4 parts by weight The protective layer coating solution was dip-coated on the dried conductive support after forming the charge transport layer as described above. After coating, the solvent was dried at 80 ° C. for 10 minutes. After drying, a 160 W / cm metal halide lamp is used to irradiate the conductive support at a position 100 mm away from the lamp for 1 minute to form a 5 μm thick protective layer. It was.

[Example 2]
When preparing the reaction liquid 2, 2-isocyanatoethyl acrylate [Karenz AOI (manufactured by Showa Denko KK)] was used instead of 2-isocyanatoethyl methacrylate [Karenz MOI (manufactured by Showa Denko KK)]. A photoconductor was prepared in the same manner as Example 1 except for the above.

[Example 3]
When preparing the reaction solution 1, octafluoropentyl acrylate [Biscoat 8F (manufactured by Osaka Organic Chemical Industry Co., Ltd.)] was used instead of the one-end reactive silicone oil [X-22-174DX (manufactured by Shin-Etsu Silicone)]. A photoconductor was prepared in the same manner as Example 1 except for the above.

[Example 4]
When preparing the reaction solution 1, a photoconductor was prepared in the same manner as in Example 1 except that the reaction time was shortened and the weight average molecular weight of the silane coupling agent was adjusted to 5000.

[Example 5]
Instead of ATO [T-1 (Mitsubishi Electronics Material Chemical Co., Ltd.)] as the metal oxide to be surface-treated, phosphorus-doped tin oxide (hereinafter referred to as PTO) [SP-2 (Mitsubishi Electronics Material Chemical Co., Ltd.)] A photoconductor was prepared in the same manner as in Example 1 except that was used.

[Example 6]
Instead of ATO [T-1 (Mitsubishi Electronics Material Chemical Co., Ltd.)] as the metal oxide to be surface-treated, PTO [CX-S204IP (Nissan Chemical Industries) (solid content 20% IPA sol solution)] is used. A photoconductor was prepared in the same manner as in Example 1 except that the reaction solution 2 and the metal oxide were mixed at the following ratio without stirring the dispersion solvent and stirred for 6 hours.
Reaction solution 2 0.1 part by weight Metal oxide 50 parts by weight (solid content 10 parts by weight)

[Example 7]
As in Example 1, except that ATO [T-1 (Mitsubishi Electronics Material Chemical Co., Ltd.)] was used as the metal oxide to be surface-treated, needle-shaped ATO [FS-10P (Ishihara Sangyo)] was used. Thus, a photoconductor was prepared. The metal oxide used had a major axis length of 0.2 to 2.0 μm, a minor axis length of 0.01 to 0.02 μm, and an aspect ratio of 20 to 30. A scanning electron microscope was used to measure the length.

[Example 8]
Example 1 except that tin oxide [S-2000 (manufactured by Mitsubishi Electronic Material Chemical Co., Ltd.)] was used instead of ATO [T-1 (manufactured by Mitsubishi Electronic Material Chemical Co., Ltd.)] as the metal oxide to be surface-treated. A photoreceptor was prepared in the same manner as described above.

[Example 9]
A photoconductor in the same manner as in Example 1 except that titanium oxide [MT500B (Taika Corporation)] was used instead of ATO [T-1 (Mitsubishi Electronics Material Chemical Co., Ltd.)] as the metal oxide to be surface-treated. Was made.

[Example 10]
Instead of ATO [T-1 (Mitsubishi Electronics Material Chemical Co., Ltd.)] as the metal oxide to be surface-treated, antimony-doped zinc oxide (hereinafter referred to as AZO) [CX-Z210IP (manufactured by Nissan Chemical Industries) (solid content) 20% IPA sol solution)] was used, and a photoreceptor was prepared in the same manner as in Example 1 except that the reaction solution 2 and the metal oxide were mixed at the following ratio without stirring the dispersion solvent and stirred for 6 hours.
Reaction solution 2 0.1 part by weight Metal oxide 50 parts by weight (solid content 10 parts by weight)

[Example 11]
Except for using urethane triacrylate oligomer [UV-7605B (manufactured by Nihon Gosei Co., Ltd.)] as a photocurable resin, ditrimethylolpropane tetraacrylate monomer [SR355 (manufactured by Sartomer)] which is a tetrafunctional acrylic monomer was used. A photoreceptor was prepared in the same manner as in Example 1.

[Example 12]
As a photocurable resin, in place of 10 parts by weight of urethane acrylate oligomer [UV-7605B (manufactured by Nihon Gosei Co., Ltd.)], 5 parts by weight of urethane acrylate oligomer [UV-7605B (manufactured by Nihon Gosei Co., Ltd.)] and polyacrylate A photoconductor was prepared in the same manner as in Example 1 except that 5 parts by weight of dendrimer [SIRIUS-501 (manufactured by Osaka Organic Chemical Industry)] was used.

[Example 13]
As a photocurable resin, instead of 10 parts by weight of urethane acrylate oligomer [UV-7605B (made by Nihon Gosei Co., Ltd.)], 4 parts by weight of urethane acrylate oligomer [UV-7605B (made by Nihon Gosei Co., Ltd.)], urethane acrylate oligomer Example 1 except that 1 part by weight of [UT-5670 (manufactured by Nihon Gosei Co., Ltd.)] and 5 parts by weight of polyacrylate dendrimer [SIRIUS-501 (manufactured by Osaka Organic Chemical Industry)] were used. A photoconductor was produced in the same manner.

[Example 14]
A photoconductor was prepared in the same manner as in Example 1 except that a gallium phthalocyanine pigment (V type) was used in place of the oxotitanyl phthalocyanine pigment (Y type) as the charge generation layer pigment.

[Example 15]
Except for using 10 parts by weight of oxo titanyl phthalocyanine pigment (Y type) as a pigment in the charge generation layer, 5 parts by weight of oxo titanyl phthalocyanine pigment (Y type) and 5 parts by weight of gallium phthalocyanine pigment (V type) were used. A photoreceptor was prepared in the same manner as in Example 1.

[Example 16]
When the surface treatment is not performed on the metal oxide, that is, when the protective layer coating solution is prepared, ATO [T-1 (manufactured by Mitsubishi Electronic Materials Chemical Co., Ltd.)] is used instead of the ATO solution so that the solid content is 20% by weight. A photoconductor was prepared in the same manner as in Example 1 except that a solution containing

[Example 17]
Example 1 except that 1 part by weight of 3-methacryloxypropyltrimethoxysilane [Dynasylan MEMO (manufactured by Evonik)] was used in place of 0.1 part by weight of the reaction solution 2 when performing the surface treatment of the metal oxide. A photoreceptor was prepared in the same manner as described above.

[Example 18]
The surface treatment was not performed on the metal oxide in the same manner as in Example 16, except that 0.1 parts by weight of both end-modified silicone [X-22-2445 (manufactured by Shin-Etsu Silicone)] was added to the same protective layer coating solution as in Example 1. A photoreceptor was prepared in the same manner as in Example 1.

Example 19
Example except that alumina [Sumicorundum AA-03 (manufactured by Sumitomo Chemical Co., Ltd.)] was used instead of ATO [T-1 (manufactured by Mitsubishi Electronic Material Chemical Co., Ltd.)] as the metal oxide to be surface-treated. A photoreceptor was prepared in the same manner as in Example 1.

[Example 20]
As in Example 1, except that silica [KMPX-100 (manufactured by Shin-Etsu Chemical Co., Ltd.)] was used instead of ATO [T-1 (manufactured by Mitsubishi Electronic Material Chemical Co., Ltd.)] as the metal oxide to be surface-treated. Thus, a photoreceptor was produced.

[Example 21]
When preparing the reaction solution 1, a photoconductor was produced in the same manner as in Example 1 except that the reaction time was increased and the weight average molecular weight of the silane coupling agent was adjusted to 120,000.

[Example 22]
A photoconductor was prepared in the same manner as in Example 1 except that metal-free phthalocyanine (X type) was used in place of the oxo titanyl phthalocyanine pigment (Y type) as the charge generation layer pigment.

  The produced photoreceptor was measured and evaluated as follows. The results are shown in Table 2.

<Initial characteristics>
Martens hardness was measured with a microhardness meter [Picodenter HM500 manufactured by Fischer Instruments Co., Ltd.]. Moreover, the elastic work factor when it pushed in with the load of 1 mN using the hardness meter was measured.

  The pure water contact angle was measured with a drop-type contact angle meter (manufactured by Kyowa Interface Chemical Co., Ltd.).

<Potential measurement>
After exposure at 30 ° C. and a humidity of 80%, the potential VL was measured with a measuring probe of a surface potentiometer [manufactured by Trek Japan, model number: MODEL344].

Thereafter, the photoconductor was mounted on an electrophotographic apparatus [CLX-8650ND manufactured by Samsung Co., Ltd.], and 300,000 A4 images with a YMCBk color printing rate of 2.5% were printed on neutral paper of A4 size. After printing 300,000 sheets, the exposed potential VL _300k was measured with a measuring probe in the same manner as the initial potential VL.

<Image blur>
After printing 300,000 sheets in the same manner as the potential measurement, a 5% text chart was printed to determine the presence or absence of image blur and image flow. The results are shown in Table 2 as follows.
◎: No image blur / flow generation ○: Minor image blur / flow generation (no problem in actual use)
×: Image blur / flow occurrence

<Poor cleaning>
After the image blur evaluation, a halftone (HT) image was formed at 23 ° C. and a humidity of 55%, and visually judged according to the following evaluation criteria. The results are shown in Table 2 as follows.
◎: No image defect due to poor cleaning ○: Minor image defect due to poor cleaning (no problem in actual use)
×: Image defect due to defective cleaning

<Blade squeal>
After evaluation of poor cleaning, print 300,000 A4 images with 2.5% YMCBk color coverage on A4 size neutral paper using the same electrophotographic device used for potential measurement at 10 ° C and 20% humidity. The blade squealed. The results are shown in Table 2 as follows.
◎: No blade squeezing until 300,000 sheets are finished ○: Slight squeal when starting and stopping the photoreceptor (no problem in actual use)
X: Continuous blade noise

<Scratches>
After evaluation of the blade noise, the surface of the photoreceptor was visually confirmed. The results are shown in Table 2 as follows.
◎: No noticeable scratches ○: 1 to 5 scratches (no problem in actual use)
×: 6 or more scratches

<Membrane wear amount>
The initial film thickness of the photoreceptor and the film thickness after blade squeal evaluation were measured with an eddy current film thickness meter [Fischer Scope MMS manufactured by Fisher Instruments Co., Ltd.]. The value obtained by dividing the difference between the initial film thickness and the film thickness after blade squeal evaluation by the number of revolutions of the photoconductor in kilo units was taken as the film depletion amount. In Table 2, “k cycles” indicates the number of revolutions of the photoconductor expressed in kilo units. For example, 10 kcycles indicate that the photoconductor has rotated 10,000 times.

  The photoreceptors of Examples 1 to 15 had a small change in potential after printing 300,000 sheets, and good electrical characteristics. Also, the evaluation results of image blur after printing, poor cleaning, blade noise, and scratches were good. Furthermore, the amount of film depletion was small, and good results were obtained. As described above, the results required for the photosensitive member were satisfied over a long period of time. From these results, a long-lasting photoreceptor that has little wear on the surface of the photoreceptor, can maintain cleaning properties, has good scratch resistance, and does not cause filming or image blurring. It was confirmed that it was obtained.

  In Example 16, the cleaning blade was reversed during printing. This is because, as can be seen from the fact that the contact angle of water was smaller than that of Example 1, sufficient slidability could not be obtained with the metal oxide not subjected to the surface treatment.

  In Example 17, the cleaning blade was reversed during printing. This is because, as can be seen from the fact that the contact angle of water was smaller than that in Example 1, sufficient slidability could not be obtained with a silane coupling agent having no lubrication site in the side chain.

  In Example 18, since both terminal-modified silicones were added to the protective layer as a slidability modifier, the contact angle of water was large and the initial slidability was sufficient, but the slidability after printing 300,000 sheets Lost and caused problems such as poor cleaning. This is because a phenomenon occurs in which both terminal-modified silicones segregate on the surface, and the effect is lost during printing due to wear. On the other hand, in Example 1, since the silane coupling agent was uniformly dispersed in the film, segregation hardly occurred and the effect was sustained.

  In Example 19 using alumina as the metal oxide and Example 20 using silica, sufficient sensitivity could not be obtained, and evaluation after printing could not be performed. This is considered to be related to the resistance value of the metal oxide. On the other hand, in the example using the metal oxide containing tin oxide, zinc oxide, or titanium oxide (for example, Example 1 and Examples 5 to 10), good electrical characteristics were obtained.

  From the results of Example 1, Example 4, and Example 21, when the molecular weight of the silane coupling agent exceeds 100,000, the surface hardness of the photoreceptor is weaker than that of 100,000 or less, and the amount of film wear tends to increase. It was seen. Although the details are unknown, it is considered that the reaction of the photocurable resin is hindered by an increase in the molecular structure of the silane coupling agent. In Example 21, the potential after printing 300,000 sheets was larger than in Examples 1 and 4, suggesting that the molecular weight of the silane coupling agent also affects the electrical characteristics. This is thought to be because unreacted functional groups can trap charges.

  In Example 22 in which metal-free phthalocyanine was used as the pigment of the charge generation layer, the potential and the amount of change thereof were compared with the examples in which at least one of oxotitanyl phthalocyanine and gallium phthalocyanine was used (for example, Example 1, Example 14, Example 15). Became larger. From this result, it is considered that the pigment of the charge generation layer affects the sensitivity characteristics of the photoreceptor depending on the type.

  As mentioned above, although this invention was demonstrated in detail based on embodiment and an Example, this is for demonstrating this invention concretely, This invention is not limited to this. It is obvious that those having ordinary knowledge in the relevant field can make modifications and improvements within the technical idea of the present invention. Any simple modifications or changes of the present invention belong to the scope of the present invention, and the specific protection scope of the present invention includes other embodiments.

Claims (14)

In an electrophotographic photosensitive member provided with at least a charge generation layer, a charge transport layer, and a protective layer in this order on a conductive support,
The protective layer includes a photocurable resin and a metal oxide surface-treated with a silane coupling agent,
The metal oxide includes tin oxide, zinc oxide or titanium oxide,
The silane coupling agent is a graft polymer having a silane coupling site bonded to the metal oxide, a photoreactive site, and a lubricating site containing at least one of fluorine and silicon in the side chain. Electrophotographic photoreceptor.   The electrophotographic photosensitive member according to claim 1, wherein the silane coupling agent is a graft polymer having an acrylic main chain. The electrophotographic photosensitive member according to claim 1, wherein the silane coupling site includes a site represented by the general formula (1).

In the formula, R ₁ is an alkoxy group, and a is an integer of 0-2. The electrophotographic photoreceptor according to claim 3, wherein R ₁ is a methoxy group, and a is 0. The electrophotographic photosensitive member according to claim 1, wherein the photoreactive site includes a site represented by the general formula (2).

In the formula, R ₂ is an alkyl group, and Y is a photoreactive functional group.   The electrophotographic photoreceptor according to claim 5, wherein Y is an acryloyl group or a methacryloyl group. The electrophotographic photosensitive member according to claim 1, wherein the lubricious portion includes a portion represented by the general formula (3).

In the formula, X ₁ is an alkyl group, X ₂ and X ₃ are each an alkyl group or an aryl group, and n ₁ and n ₂ are each an integer of _{1 to} 500. The electrophotographic photosensitive member according to claim 1, wherein the lubricious portion includes a portion represented by the general formula (4).

In the formula, m is an integer of 1 to 400.   The electrophotographic photosensitive member according to claim 1, wherein the silane coupling agent has a weight average molecular weight of 300 to 100,000.   The electrophotographic photosensitive member according to claim 1, wherein the metal oxide has an average primary particle size of 5 nm to 300 nm.   The electrophotographic photosensitive member according to claim 1, wherein the metal oxide has an aspect ratio of 3 or more.   The photocurable resin according to any one of claims 1 to 11, wherein the photocurable resin is an acrylic resin formed from at least one starting material selected from the group consisting of acrylic monomers, oligomers, and dendrimers. The electrophotographic photosensitive member described.   The electrophotographic photosensitive member according to claim 1, wherein the charge generation layer contains at least one of oxotitanyl phthalocyanine and gallium phthalocyanine.   The electrophotographic photosensitive member according to any one of claims 1 to 13, a charging unit for charging the electrophotographic photosensitive member, and exposing the charged electrophotographic photosensitive member to expose the electrophotographic photosensitive member. An image exposure unit for forming an electrostatic latent image thereon; a developing unit for developing the electrostatic latent image formed on the electrophotographic photosensitive member with toner; and a toner image as a transfer material. An electrophotographic apparatus comprising: cleaning means for removing toner remaining on the electrophotographic photosensitive member after the transfer.

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