JP4339197B2 - Electrophotographic photosensitive member, electrophotographic method using the same, electrophotographic apparatus and process cartridge - Google Patents

Description

  The present invention relates to an electrophotographic photoreceptor having high durability and realizing high image quality. The present invention also relates to an electrophotographic method, an electrophotographic apparatus, and a process cartridge for an electrophotographic apparatus using the photoconductor.

In recent years, there has been a remarkable development in information processing system machines using electrophotography. In particular, laser printers and digital copying machines that convert information into digital signals and record information using light have significantly improved print quality and reliability. Furthermore, they have been applied to laser printers or digital copiers capable of full-color printing by fusing with high-speed technology. From such a background, it is particularly important to achieve both high image quality and high durability as a required photoreceptor function.
As photoconductors used in these electrophotographic laser printers, digital copiers, etc., those using organic photosensitive materials are widely applied for reasons such as cost, productivity and non-pollution. . The organic electrophotographic photoreceptor includes a photoconductive resin typified by polyvinylcarbazole (PVK), a charge transfer complex type typified by PVK-TNF (2,4,7-trinitrofluorenone), Known are a pigment dispersion type typified by a phthalocyanine binder, and a function separation type photoreceptor using a combination of a charge generation material and a charge transport material.
The mechanism of electrostatic latent image formation in the function-separated type photoconductor is that when the photoconductor is charged and then irradiated with light, the light passes through the charge transport layer and is absorbed by the charge generation material in the charge generation layer to generate a charge. . The charges generated thereby are injected into the charge transport layer at the interface between the charge generation layer and the charge transport layer, and further moved through the charge transport layer by an electric field, thereby neutralizing the surface charge of the photoreceptor, thereby forming an electrostatic latent image. To form.
However, organic photoconductors are prone to film scraping due to repeated use, and as the photoconductive layer progresses, the photoconductor is charged, the photosensitivity is deteriorated, the surface of the photoconductor is scratched, etc. However, there is a strong tendency for image density reduction or image quality degradation to be accelerated, and conventionally, the abrasion resistance of a photoreceptor has been cited as a major issue. Further, in recent years, with the increase in the speed of the electrophotographic apparatus or the reduction in the diameter of the photoreceptor accompanying the downsizing of the apparatus, it has become a more important issue to improve the durability of the photoreceptor.

On the other hand, in recent years, with a demand for higher image quality in the market, a small-diameter, spherical toner has attracted attention. However, such a small-diameter and spherical toner has a high transferability on the photosensitive member, so that it tends to cause a cleaning failure and causes image deterioration due to toner filming or fusing. Has become an important issue.
In order to solve such a problem, for example, as disclosed in Patent Documents 1 and 2 and the like, a photoreceptor surface friction coefficient aimed at a surface release effect in which fluororesin fine particles are contained in the surface layer of the photoreceptor as a lubricant. The technique by reducing the initial value is effective. However, in these, it is necessary to set conditions such as a cleaning system and toner, and for the deterioration and variation of these peripheral members due to the longer life of the photosensitive member, it is necessary to maintain the surface release effect by repeated use. It was insufficient.
In the invention disclosed in Patent Document 3, the surface layer of the photosensitive layer contains polytetrafluoroethylene powder as a lubricant and contains a charge transport material having a specific structural formula, so that the surface of the photosensitive layer is rubbed. It is possible to provide a highly durable electrophotographic photosensitive member that is durable against the occurrence of abrasion and scratches and that can provide a high-quality image free from image blurring. It is said that an electrophotographic photosensitive member having high durability without toner adhesion to the body surface layer can be provided. However, since a large amount of fluororesin fine particles are added, a sufficient effect cannot be expected with the compounds shown in this document. In addition, its own oxidation-reduction potential is low and easily deteriorates, and it is easy to form a charge trap and easily raise the residual potential.

JP-A-5-45920 JP 2000-19918 A JP-A-8-160648

  An object of the present invention is to provide a photoconductor that has high durability, suppresses image deterioration such as afterimage due to increase in residual potential or decrease in charge, and can stably obtain high-quality images even after repeated use over a long period of time. There is. In addition, by using these photoconductors, it is not necessary to replace the photoconductors, and it is possible to reduce the size of the apparatus due to high-speed printing or reducing the diameter of the photoconductor, and to stably obtain high-quality images even during repeated use. The present invention provides an electrophotographic method, an electrophotographic apparatus, and an electrophotographic process cartridge.

（式中、Ｒ^１、Ｒ^２ の何れか一方は、置換又は無置換のアルキル基であり、他方は、アルキル基若しくはアルコキシ基により置換された又は無置換の芳香族炭化水素基を表す。Ａｒは置換若しくは無置換の芳香族炭化水素基を表す。）
２） １）記載の電子写真感光体を用い、該電子写真感光体に、少なくとも帯電、画像露光、現像、転写を繰り返し行うことを特徴とする電子写真方法。
３） 画像露光の際に、ＬＤ或いはＬＥＤによって感光体上に静電潜像の書き込みを行うことを特徴とする２）記載の電子写真方法。
４） 画像形成に使用されるトナーの形状が球状であることを特徴とする２）又は３）記載の電子写真方法。
５） 帯電ローラー、クリーニングブレード、クリーニングブラシ、中間転写ベルトを備えた電子写真装置を使用し、これらの部材の少なくとも一つを前記電子写真感光体表面に接触させて、帯電、画像露光、現像、転写を繰り返し行うことを特徴とする２）〜４）の何れかに記載の電子写真方法。
６） 少なくとも帯電手段、画像露光手段、現像手段、転写手段及び１）記載の電子写真感光体を具備することを特徴とする電子写真装置。
７） 画像露光手段としてＬＤ或いはＬＥＤを備え、これにより感光体上に静電潜像の書き込みが行われることを特徴とする６）記載の電子写真装置。
８） 複数の電子写真感光体、帯電手段、現像手段、転写手段を有するタンデム型であることを特徴とする６）又は７）記載の電子写真装置。
９） 電子写真感光体上に現像されたトナー画像を中間転写体上に一次転写したのち、該中間転写体上のトナー画像を記録材上に二次転写する中間転写手段を有し、複数色のトナー画像を中間転写体上に順次重ね合わせてカラー画像を形成し、該カラー画像を記録材上に一括で二次転写することを特徴とする６）又は７）記載の電子写真装置。
１０） 帯電手段、露光手段、現像手段、クリーニング手段、転写手段の少なくとも一つと１）記載の電子写真感光体とを具備する電子写真装置用プロセスカートリッジ。 The above problems are solved by the following inventions 1) to 10 ).
1) In an electrophotographic photoreceptor in which the outermost surface layer of the photosensitive layer formed on the conductive support is a protective layer containing fluororesin fine particles as a solid lubricant, the protective layer has a volume fraction of 20 to 60. % Of fluororesin fine particles, and at least one compound represented by the following general formula (a).

(In the formula, either one of R ¹ and R ² is a substituted or unsubstituted alkyl group , and the other represents an aromatic hydrocarbon group substituted or unsubstituted by an alkyl group or an alkoxy group. Represents a substituted or unsubstituted aromatic hydrocarbon group.)
2) An electrophotographic method using the electrophotographic photosensitive member according to 1) , wherein at least charging, image exposure, development, and transfer are repeated on the electrophotographic photosensitive member.
3) During image exposure, 2 and performs writing of an electrostatic latent image on the photosensitive member by LD or LED) electrophotographic method according.
4) The electrophotographic method according to 2) or 3), wherein the toner used for image formation has a spherical shape.
5) Using an electrophotographic apparatus equipped with a charging roller, a cleaning blade, a cleaning brush, and an intermediate transfer belt , contacting at least one of these members with the surface of the electrophotographic photosensitive member, charging, image exposure, development, The electrophotographic method according to any one of 2) to 4) , wherein the transfer is repeated .
6) An electrophotographic apparatus comprising at least a charging unit, an image exposing unit, a developing unit, a transferring unit, and the electrophotographic photosensitive member described in 1) .
7) The electrophotographic apparatus according to 6) , wherein an LD or LED is provided as image exposure means , whereby an electrostatic latent image is written on the photoreceptor.
8) The electrophotographic apparatus according to 6) or 7) , wherein the electrophotographic apparatus is a tandem type having a plurality of electrophotographic photosensitive members, a charging unit, a developing unit, and a transfer unit.
9) Having an intermediate transfer means for primary transfer of the toner image developed on the electrophotographic photosensitive member onto the intermediate transfer member and then secondary transfer of the toner image on the intermediate transfer member onto the recording material. 6. The electrophotographic apparatus according to 6) or 7) , wherein the toner images are sequentially superimposed on an intermediate transfer member to form a color image, and the color image is secondarily transferred onto a recording material at once.
10) A process cartridge for an electrophotographic apparatus, comprising at least one of charging means, exposure means, developing means, cleaning means, and transfer means and the electrophotographic photosensitive member described in 1) .

Hereinafter, the present invention will be described in detail.
In order to achieve high durability and low surface friction coefficient of the electrophotographic photosensitive member, it is known that it is effective to contain fluororesin fine particles in the outermost surface layer of the photosensitive member, but a highly stable low surface In order to maintain the durability of the friction coefficient, fluororesin fine particles having a volume fraction of 20% or more are required. Usually, when a layer having such a structure is to be formed, since the interaction between the particles of the fluororesin fine particles becomes large, it becomes difficult to finely disperse the fluororesin fine particles in the dispersion, and the resulting coating film The secondary agglomerated particles (secondary particles) in the medium increase. If such secondary particles are too large in the coating film, the surface of the coating film becomes rough, resulting in poor cleaning and disorder of the toner image. In addition, the laser light is scattered on the aggregates, and the exposure latent image is disturbed and the potential contrast is insufficient to cause an abnormal image.
On the other hand, when the particles are uniformly dispersed to the primary particles, the above-mentioned problems are solved, but on the other hand, the portion where the fluororesin fine particles are exposed on the surface of the coating is reduced, resulting in the toner and the fluororesin. The contact area with the fine particles decreases, and the effect of reducing the surface friction coefficient of the photoreceptor becomes insufficient.

As a result of intensive studies, the present inventors need to localize the fluorine fine particles in a certain range and cover a certain area of the coating film surface in consideration of the cleaning property of the toner. I found out. That is, it has been found that the secondary particle diameter of the fluorine fine particles of 0.3 to 4 μm is most preferable when the surface of the photoreceptor is covered by 10 to 60% in area ratio.
However, in such a photoreceptor having a high concentration of secondary particles of fluororesin fine particles, the chargeability may be reduced depending on the use conditions, which may cause problems such as a memory effect (afterimage). Oxidizing gases such as NOx and NOx are easily adsorbed, and in some cases, the resistance of the outermost surface is lowered, which may cause problems such as image flow.
As a result of further investigations, it has been found that the problem with respect to the memory effect and the oxidizing gas can be solved by containing at least one selected from the compounds represented by the general formula (a ) . The reason for this is not clarified at the present time, but it is presumed that the generation of radical substances that are likely to accumulate inside the heterogeneous particle structure is effectively suppressed. On the other hand, for an oxidizing gas, it is presumed that the substituted amino group contained in the structure effectively suppresses the generation of radical substances. Moreover, since the said compound also has a charge transport capability, it is thought that the charge trap inside the secondary aggregation particle | grains by a fluororesin particle | grain is suppressed.

The amount of the compound represented by the general formula (a ) is preferably 0.01 to 150% by weight with respect to the binder resin. If the amount is too small, the resistance to the oxidizing gas is insufficient. If the amount is too large, the film strength is lowered and the wear resistance is deteriorated.
Specific examples of the alkyl group in the general formula (a ) include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, and an undecyl group. The aromatic ring group includes monovalent to hexavalent aromatic hydrocarbon groups composed of aromatic hydrocarbon rings such as benzene, naphthalene, anthracene and pyrene, and pyridine, quinoline, thiophene, furan, oxazole, oxadiazole, Examples thereof include monovalent to hexavalent aromatic heterocyclic groups composed of aromatic heterocyclic rings such as carbazole . In addition, as substituents of these rings, those exemplified in the specific examples of the alkyl group , alkoxy groups such as methoxy group, ethoxy group, propoxy group, butoxy group , fluorine atom, chlorine atom, bromine atom, iodine atom A halogen atom, an aromatic ring group, etc. are mentioned.
Hereinafter, preferred examples of the compound represented by the general formula (a ) are listed in Table 1 . However, the present invention is not limited to these compounds.

Hereinafter, examples of the layer structure of the electrophotographic photosensitive member of the present invention will be described with reference to the drawings.
The electrophotographic photosensitive member of FIG. 1 has a configuration in which a photosensitive layer 33 mainly composed of a charge generation material and a charge transport material, and a protective layer 39 are laminated on a conductive support 31 in this order. The protective layer 39 contains fluororesin fine particles.
The electrophotographic photosensitive member of FIG. 2 has a charge generation layer 35 mainly composed of a charge generation material, a charge transport layer 37 mainly composed of a charge transport material, and a protective layer 39 in this order on a conductive support 31. It has a stacked configuration. The protective layer 39 contains fluororesin fine particles.
In the electrophotographic photosensitive member of FIG. 3, a charge transport layer 37 containing a charge transport material as a main component, a charge generation layer 35 containing a charge generation material as a main component, and a protective layer 39 are arranged in this order on a conductive support 31. It has a stacked configuration. The protective layer 39 contains fluororesin fine particles.

Examples of the conductive support 31 include those having a volume resistance of 10 ¹⁰ Ω · cm or less, for example, metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, indium oxide, etc. A metal or metal plastic film or cylindrical plastic or paper coated by vapor deposition or sputtering, or a plate made of aluminum, aluminum alloy, nickel, stainless steel, etc. After being converted, a tube subjected to surface treatment such as cutting, superfinishing or polishing can be used. Further, an endless nickel belt or an endless stainless steel belt disclosed in Japanese Patent Application Laid-Open No. 52-36016 can also be used as the conductive support 31.
In addition, a material obtained by dispersing conductive powder in an appropriate binder resin and coating it on the support can also be used as the conductive support 31 of the present invention. Examples of the conductive powder include carbon black and acetylene black; metal powder such as aluminum, nickel, iron, nichrome, copper, zinc, and silver; metal oxide powder such as conductive tin oxide and ITO.

Examples of the binder resin include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyacetic acid. Vinyl, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, Examples thereof include thermoplastic resins such as urethane resin, phenol resin, and alkyd resin, thermosetting resin, and photo-curable 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, by a heat shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, Teflon (registered trademark) on a suitable cylindrical substrate. What provided the electroconductive layer can also be used favorably as the electroconductive support body 31 of this invention.

Next, the photosensitive layer will be described. The photosensitive layer may be a single layer or a laminate, but for convenience of explanation, the case where it is composed of the charge generation layer 35 and the charge transport layer 37 will be described first (in the case of FIGS. 2 and 3).
The charge generation layer 35 is a layer mainly composed of a charge generation material. A known charge generation material can be used for the charge generation layer 35, and representative examples thereof include monoazo pigments, disazo pigments, trisazo pigments, perylene pigments, perinone pigments, quinacridone pigments, and quinone condensed polycycles. Examples thereof include compounds, squaric acid dyes, other phthalocyanine pigments, naphthalocyanine pigments, and azulenium salt dyes. These charge generation materials may be used alone or in combination of two or more.
In the charge generation layer 35, a charge generation material is dispersed in a suitable solvent together with a binder resin as necessary using a ball mill, an attritor, a sand mill, an ultrasonic wave, etc., and this is applied onto a conductive support. It is formed by drying.

The binder resin used as necessary includes polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly-N-vinylcarbazole, poly Examples include acrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, and polyvinyl pyrrolidone. The amount of the binder resin is suitably 0 to 500 parts by weight, preferably 10 to 300 parts by weight with respect to 100 parts by weight of the charge generating material. The binder resin may be added before or after dispersion.
Examples of the solvent include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin, etc. , Ester solvents and ether solvents are preferably used. These may be used alone or in combination of two or more.
The charge generation layer 35 mainly includes a charge generation material, a solvent, and a binder resin, but may contain various additives such as a sensitizer, a dispersant, a surfactant, and silicone oil.
As a coating method of the coating solution, methods such as dip coating, spray coating, beat coating, nozzle coating, spinner coating, ring coating, and the like can be used.
The thickness of the charge generation layer 35 is suitably about 0.01 to 5 μm, preferably 0.1 to 2 μm.

The charge transport layer 37 can be formed by dissolving or dispersing a charge transport material and a binder resin in a suitable solvent, and applying and drying the solution on the charge generation layer. In addition, one or more plasticizers, leveling agents, antioxidants and the like can be added as necessary.
Charge transport materials include electron transport materials and hole transport materials.
Examples of the electron transporting material include chloroanil, bromoanil, 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 benzoquinone derivatives.
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, oxazole derivatives, Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazolines Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, etc., bisstilbene derivatives, enamine derivatives, etc. Known materials may be mentioned.
These charge transport materials may be used alone or in combination of two or more.

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 with respect to 100 parts by weight of the binder resin. The thickness of the charge transport layer is preferably 25 μm or less from the viewpoint of resolution and responsiveness. The lower limit varies depending on the system to be used (particularly charging potential), but is preferably 5 μm or more.
As the solvent, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone and the like are used. These may be used alone or in combination of two or more.

〔式中、Ｒ_１，Ｒ_２，Ｒ_３はそれぞれ独立して置換若しくは無置換のアルキル基又はハロゲン原子、Ｒ_４は水素原子又は置換若しくは無置換のアルキル基、Ｒ_５，Ｒ_６は置換若しくは無置換のアリール基、ｏ，ｐ，ｑはそれぞれ独立して０〜４の整数、ｋ，ｊは組成を表し、０．１≦ｋ≦１、０≦ｊ≦０．９、ｎは繰り返し単位数を表し５〜５０００の整数である。Ｘは脂肪族の２価基、環状脂肪族の２価基、又は下記一般式（Ｉ−１）、（Ｉ−２）で表される２価基を表す。〕
一般式（Ｉ−１）

〔式中、Ｒ_１０１，Ｒ_１０２は各々独立して置換若しくは無置換のアルキル基、アリール基又はハロゲン原子を表す。ｌ，ｍは０〜４の整数、Ｙは単結合、炭素原子数１〜１２の直鎖状、分岐状若しくは環状のアルキレン基、−Ｏ−、−Ｓ−、−ＳＯ−、−ＳＯ_２−、−ＣＯ−、−ＣＯ−Ｏ−Ｚ−Ｏ−ＣＯ−（Ｚは脂肪族の２価基）を表す。〕
一般式（Ｉ−２）

（式中、ａは１〜２０の整数、ｂは１〜２０００の整数、Ｒ_１０３，Ｒ_１０４は置換若しくは無置換のアルキル基又はアリール基を表す。）を表す。ここで、Ｒ_１０１とＲ_１０２，Ｒ_１０３とＲ_１０４は、それぞれ同一でも異なってもよい。） For the charge transport layer, a polymer charge transport material having a function as a charge transport material and a function as a binder resin is also preferably used. The charge transport layer composed of these polymer charge transport materials is excellent in wear resistance. As the polymer charge transporting material, known materials can be used, and in particular, a polycarbonate containing a triarylamine structure in the main chain and / or side chain is preferably used. Among these, polymer charge transport materials represented by the following general formulas (I) to (X) are preferable.
Formula (I)

[Wherein R ₁ , R ₂ and R ₃ are each independently a substituted or unsubstituted alkyl group or a halogen atom, R ₄ is a hydrogen atom or a substituted or unsubstituted alkyl group, and R ₅ and R ₆ are substituted or Unsubstituted aryl group, o, p and q are each independently an integer of 0 to 4, k and j represent a composition, 0.1 ≦ k ≦ 1, 0 ≦ j ≦ 0.9, and n is a repeating unit It represents a number and is an integer from 5 to 5000. X represents an aliphatic divalent group, a cycloaliphatic divalent group, or a divalent group represented by the following general formulas (I-1) and (I-2). ]
Formula (I-1)

[Wherein, R ₁₀₁ and R ₁₀₂ each independently represents a substituted or unsubstituted alkyl group, aryl group or halogen atom. l and m are integers of 0 to 4, Y is a single bond, a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms, —O—, —S—, —SO—, —SO ₂ —. , -CO-, -CO-O-Z-O-CO- (Z is an aliphatic divalent group). ]
Formula (I-2)

(Wherein, a represents an integer of 1 to 20, b represents an integer of 1 to 2000, and R ₁₀₃ and R ₁₀₄ represent a substituted or unsubstituted alkyl group or an aryl group). Here, R ₁₀₁ and R ₁₀₂ , R ₁₀₃ and R ₁₀₄ may be the same or different. )

〔式中、Ｒ_７，Ｒ_８は置換若しくは無置換のアリール基、Ａｒ_１，Ａｒ_２，Ａｒ_３は同一又は異なるアリレン基を表す。Ｘ，ｋ，ｊ，ｎは、一般式（Ｉ）の場合と同じである。〕 Formula (II)

[Wherein R ₇ and R ₈ represent a substituted or unsubstituted aryl group, and Ar ₁ , Ar ₂ and Ar ₃ represent the same or different arylene groups. X, k, j, and n are the same as in the general formula (I). ]

〔式中、Ｒ_９，Ｒ_１０は置換若しくは無置換のアリール基、Ａｒ_４，Ａｒ_５，Ａｒ_６は同一又は異なるアリレン基を表す。Ｘ，ｋ，ｊ，ｎは、一般式（Ｉ）の場合と同じである。〕 General formula (III)

[Wherein R ₉ and R ₁₀ represent a substituted or unsubstituted aryl group, and Ar ₄ , Ar ₅ and Ar ₆ represent the same or different arylene groups. X, k, j, and n are the same as in the general formula (I). ]

〔式中、Ｒ_１１，Ｒ_１２は置換若しくは無置換のアリール基、Ａｒ_７，Ａｒ_８，Ａｒ_９は同一又は異なるアリレン基を表す。Ｘ，ｋ，ｊ，ｎは、一般式（Ｉ）の場合と同じである。〕 Formula (IV)

[Wherein R ₁₁ and R ₁₂ represent a substituted or unsubstituted aryl group, and Ar ₇ , Ar ₈ and Ar ₉ represent the same or different arylene groups. X, k, j, and n are the same as in the general formula (I). ]

〔式中、Ｒ_１３，Ｒ_１４は置換若しくは無置換のアリール基、Ａｒ_１０，Ａｒ_１１，Ａｒ_１２は同一或いは異なるアリレン基、Ｘ_１，Ｘ_２は置換若しくは無置換のエチレン基、又は置換若しくは無置換のビニレン基を表す。Ｘ，ｋ，ｊ，ｎは、一般式（Ｉ）の場合と同じである。〕 General formula (V)

[Wherein R ₁₃ and R ₁₄ are substituted or unsubstituted aryl groups, Ar ₁₀ , Ar ₁₁ and Ar ₁₂ are the same or different arylene groups, X ₁ and X ₂ are substituted or unsubstituted ethylene groups, or substituted or unsubstituted An unsubstituted vinylene group is represented. X, k, j, and n are the same as in the general formula (I). ]

〔式中、Ｒ_１５，Ｒ_１６，Ｒ_１７，Ｒ_１８は置換若しくは無置換のアリール基、Ａｒ_１３，Ａｒ_１４，Ａｒ_１５，Ａｒ_１６は同一或いは異なるアリレン基、Ｙ_１，Ｙ_２，Ｙ_３は単結合、置換若しくは無置換のアルキレン基、置換若しくは無置換のシクロアルキレン基、置換若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、ビニレン基を表し、同一でも異なっていてもよい。Ｘ，ｋ，ｊ，ｎは、一般式（Ｉ）の場合と同じである。〕 General formula (VI)

[Wherein R ₁₅ , R ₁₆ , R ₁₇ , R ₁₈ are substituted or unsubstituted aryl groups, Ar ₁₃ , Ar ₁₄ , Ar ₁₅ , Ar ₁₆ are the same or different arylene groups, Y ₁ , Y ₂ , Y ₃ 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, which may be the same or different. X, k, j, and n are the same as in the general formula (I). ]

〔式中、Ｒ_１９，Ｒ_２０は水素原子、置換若しくは無置換のアリール基を表し，Ｒ_１９とＲ_２０は互いに結合して環を形成していてもよい。Ａｒ_１７，Ａｒ_１８，Ａｒ_１９は同一又は異なるアリレン基を表す。Ｘ，ｋ，ｊ，ｎは、一般式（Ｉ）の場合と同じである。〕 Formula (VII)

[Wherein R ₁₉ and R ₂₀ represent a hydrogen atom or a substituted or unsubstituted aryl group, and R ₁₉ and R ₂₀ may be bonded to each other to form a ring. Ar ₁₇ , Ar ₁₈ and Ar ₁₉ represent the same or different arylene groups. X, k, j, and n are the same as in the general formula (I). ]

〔式中、Ｒ_２１は置換若しくは無置換のアリール基、Ａｒ_２０，Ａｒ_２１，Ａｒ_２２，Ａｒ_２３は同一又は異なるアリレン基を表す。Ｘ，ｋ，ｊ，ｎは、一般式（Ｉ）の場合と同じである。〕 Formula (VIII)

[Wherein R ₂₁ represents a substituted or unsubstituted aryl group, and Ar ₂₀ , Ar ₂₁ , Ar ₂₂ , Ar ₂₃ represent the same or different arylene groups. X, k, j, and n are the same as in the general formula (I). ]

〔式中、Ｒ_２２，Ｒ_２３，Ｒ_２４，Ｒ_２５は置換若しくは無置換のアリール基、Ａｒ_２４，Ａｒ_２５，Ａｒ_２６，Ａｒ_２７，Ａｒ_２８は同一又は異なるアリレン基を表す。Ｘ，ｋ，ｊ，ｎは、一般式（Ｉ）の場合と同じである。〕 General formula (IX)

[Wherein R ₂₂ , R ₂₃ , R ₂₄ and R ₂₅ represent a substituted or unsubstituted aryl group, and Ar ₂₄ , Ar ₂₅ , Ar ₂₆ , Ar ₂₇ and Ar ₂₈ represent the same or different arylene groups. X, k, j, and n are the same as in the general formula (I). ]

〔式中、Ｒ_２６，Ｒ_２７は置換若しくは無置換のアリール基、Ａｒ_２９，Ａｒ_３０，Ａｒ_３１は同一又は異なるアリレン基を表す。Ｘ，ｋ，ｊ，ｎは、一般式（Ｉ）の場合と同じである。〕
塗布液の塗工法としては、浸漬塗工法、スプレーコート、ビートコート、ノズルコート、スピナーコート、リングコート等、従来の塗工方法を用いることができる。 Formula (X)

[Wherein R ₂₆ and R ₂₇ represent a substituted or unsubstituted aryl group, and Ar ₂₉ , Ar ₃₀ and Ar ₃₁ represent the same or different arylene groups. X, k, j, and n are the same as in the general formula (I). ]
As a coating method of the coating solution, a conventional coating method such as dip coating, spray coating, beat coating, nozzle coating, spinner coating, ring coating, or the like can be used.

Next, the case where the photosensitive layer has a single layer structure (in the case of FIG. 1) will be described.
In this case, a photoconductor in which the above-described charge generating material is dispersed in a binder resin can be used. The photosensitive layer 33 can be formed by dissolving or dispersing a charge generation material, a charge transport material and a binder resin in a suitable solvent, and applying and drying the solution. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed.
As the binder resin, in addition to the binder resin previously mentioned in the charge transport layer 37, the binder resin mentioned in the charge generation layer 35 may be mixed and used. Of course, the polymer charge transport materials listed above can also be used favorably. The amount of the charge generation material with respect to 100 parts by weight of the binder resin is preferably 5 to 40 parts by weight, and the amount of the charge transport material is preferably 0 to 190 parts by weight, and more preferably 50 to 150 parts by weight. The photosensitive layer is formed by dip coating, spray coating, bead coating, a coating solution in which a charge generating material and a binder resin are dispersed together with a charge transport material using a solvent such as tetrahydrofuran, dioxane, dichloroethane, and cyclohexane. It can be formed by coating with a ring coat or the like. The film thickness of the photosensitive layer is suitably about 5 to 25 μm.

In the photoreceptor of the present invention, an undercoat layer can be provided between the conductive support 31 and the photosensitive layer. In general, the undercoat layer is mainly composed of a resin. However, considering that the photosensitive layer is coated with a solvent on these resins, it is desirable that the resin be a resin having a high solvent resistance with respect to a general organic solvent. . Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. Further, fine powder pigments of metal oxides such as titanium oxide, silica, alumina, zirconium oxide, tin oxide, and indium oxide may be added to the undercoat layer in order to prevent moire and reduce residual potential.
These undercoat layers can be formed using an appropriate solvent and a coating method like the above-mentioned photosensitive layer. Also, as the undercoat layer of the present invention, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used, or Al ₂ O ₃ provided by anodization, polyparaxylylene (parylene) ) And other organic substances such as SiO ₂ , SnO ₂ , TiO ₂ , ITO, and CeO ₂ provided by a vacuum thin film forming method can also be used favorably. Further, other known ones can also be used. The thickness of the undercoat layer is suitably from 0 to 5 μm.

In the photoreceptor of the present invention, a protective layer 39 is provided on the photosensitive layer for the purpose of protecting the photosensitive layer and maintaining a low surface friction coefficient. The binder resin used for the protective layer 39 is ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, aryl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallyl. Sulfone, polybutylene, polybutylene terephthalate, polycarbonate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylbenten, polypropylene, polyphenylene oxide, polysulfone, polystyrene, polyarylate, AS resin, butadiene-styrene copolymer, Examples include polyurethane, polyvinyl chloride, polyvinylidene chloride, and epoxy resin. From the viewpoint of dispersibility of fluororesin fine particles, residual potential, and coating film defects, polycarbonate or polyarylate is particularly effective and useful.
Further, a filler may be added to the protective layer for the purpose of improving the wear resistance. As the filler, there are an organic filler and an inorganic filler. From the viewpoint of the hardness of the filler, the use of the inorganic filler is advantageous for improving the wear resistance. Examples of such inorganic filler materials include metal powders such as copper, tin, aluminum, and indium; silica, tin oxide, zinc oxide, titanium oxide, alumina, zirconium oxide, indium oxide, antimony oxide, bismuth oxide, and calcium oxide. Metal oxides such as tin oxide doped with antimony and indium oxide doped with tin; metal fluorides such as tin fluoride, calcium fluoride and aluminum fluoride; inorganic such as potassium titanate and boron nitride Materials.

These fillers are preferably surface-treated with at least one surface treatment agent from the viewpoint of filler dispersibility. Decreasing the dispersibility of the filler 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 treatment agent, a conventionally used surface treatment agent can be used as appropriate, but a surface treatment agent capable of maintaining the insulating properties of the filler is preferable. For example, a titanate coupling agent, an aluminum coupling agent, a zircoaluminate coupling agent, a higher fatty acid, etc., or a mixing treatment of these with a silane coupling agent, Al ₂ O ₃ , TiO ₂ , ZrO ₂ , Silicone, aluminum stearate, or the like, or a mixture thereof is more preferable from the viewpoint of filler 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 filler used, but is preferably 3 to 30% by weight, and more preferably 5 to 20% by weight. When the surface treatment amount is less than 3% by weight, the filler dispersing effect cannot be obtained, and when it is more than 30% by weight, the residual potential is significantly increased.

Examples of the fluororesin fine particles that can be used in the present invention include tetrafluoroethylene resin fine particles, perfluoroalkoxy resin fine particles, trifluorinated ethylene chloride fine resin particles, hexafluoroethylene propylene resin fine particles, vinyl fluoride resin fine particles, and fluorine. Vinylidene fluoride resin fine particles, fluorinated ethylene chloride resin fine particles and copolymers thereof, and the like, and one or more of these are appropriately selected. Particularly, tetrafluoroethylene resin fine particles, perfluoro Alkoxy resin fine particles are preferred. The particle size can be 0.1 to 10 μm, preferably 0.05 to 2.0 μm, and the particle size can be adjusted by a dispersion treatment described later as required.
The fluororesin fine particles having a secondary particle diameter of 0.3 to 4 μm must cover the surface of the photoreceptor by 10 to 60% by area ratio, preferably the secondary particle diameter is 0.3 to 1.5 μm. is there. If the coverage is less than 10%, the low surface friction coefficient when viewed microscopically becomes insufficient, and if the coverage exceeds 60%, the transmittance of the laser beam is remarkably reduced, making it difficult to form an electrostatic latent image. Become. On the other hand, if the size of the secondary particles exceeds 4 μm, the above-mentioned toner contact surface shortage may occur or abnormal images may be caused by laser light scattering.

Furthermore, in order to maintain a low surface friction coefficient even in repeated use, the fluororesin fine particles are contained in an amount of 20 to 60% by volume fraction. Preferably, it is 30 to 50%. The fluororesin fine particles are preferably dispersed and exposed on the surface. As a result, even in a photoreceptor in which the amount of wear is remarkably reduced due to low μ, a necessary and sufficient amount of fluororesin fine particles continues to be extended, so that a low surface friction coefficient and high durability are exhibited. If the volume fraction is less than 20%, even if the above-mentioned coverage can be ensured in the vicinity of the surface, the low surface friction coefficient will not be exhibited when the inside of the protective layer is exposed to the surface due to wear. On the other hand, if the volume fraction exceeds 60%, the amount of the binder resin is decreased, so that the mechanical strength of the coating film is remarkably lowered, and the life of the photoreceptor is reduced. Furthermore, if the content is large, the contact between the fluororesin fine particles increases, the aggregated secondary particles also increase, and the particle size tends to increase.
As the solvent, all solvents used in the charge transport layer 37 such as tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone, and the like can be used. However, a solvent having a high viscosity is preferable at the time of dispersion, but a solvent having high volatility is preferable at the time of coating. When there is no solvent satisfying these conditions, it is possible to use a mixture of two or more solvents having respective physical properties, which may have a great effect on the dispersibility of the fluororesin fine particles.
Further, the addition of the low molecular charge transport material or the polymer charge transport material mentioned in the charge transport layer 37 to the protective layer is effective and useful for reducing the residual potential and improving the image quality.

The fluororesin fine particles can be dispersed together with at least an organic solvent by using a conventional method such as attritor, sand mill, vibration mill, or ultrasonic wave. Of these, a ball mill or vibration mill method with less impurities from the outside is more preferred from the viewpoint of dispersibility. As the dispersion medium, various media such as zirconia, alumina and agate conventionally used can be used, and zirconia is particularly preferable from the viewpoint of the effect on the dispersibility of the fluororesin fine particles. In some cases, dispersibility may be further increased by combining these dispersion methods. Further, a dispersant may be added to the resin for the purpose of controlling the dispersibility of the fluororesin fine particles. As such a dispersant, a fluorine-based surfactant, a graft polymer, a block polymer, a coupling agent, and the like can be used.
As a method for forming the protective layer, conventional methods such as dip coating, spray coating, beat coating, nozzle coating, spinner coating, ring coating, etc. can be used. preferable. Furthermore, it is possible to form the protective layer by coating the required thickness of the protective layer at one time, but it is better to apply the coating two or more times to make the protective layer multi-layered. It is more preferable in terms of uniformity. Although the thickness of the protective layer can be set freely, it is recognized that when the protective layer thickness is significantly increased, the image quality tends to be slightly deteriorated. About 0.1-10 micrometers is suitable.
In the photoreceptor of the present invention, an intermediate layer can be provided between the photosensitive layer and the protective layer. In the intermediate layer, a binder resin is generally used as a main component. Examples of these resins include polyamide, alcohol-soluble nylon, water-soluble polyvinyl butyral, polyvinyl butyral, and polyvinyl alcohol. As a method for forming the intermediate layer, a generally used coating method is employed as described above. The thickness of the intermediate layer is suitably about 0.05 to 2 μm.

Next, the electrophotographic method and the electrophotographic apparatus of the present invention will be described with reference to the drawings.
FIG. 4 is a schematic diagram for explaining the electrophotographic process and the electrophotographic apparatus of the present invention, and the following examples also belong to the category of the present invention.
In FIG. 4, the photosensitive member 1 is provided with at least a photosensitive layer, and the outermost surface layer contains a filler. The photosensitive member 1 has a drum shape, but may be a sheet shape or an endless belt shape. As the charging charger 3, the pre-transfer charger 7, the transfer charger 10, the separation charger 11, and the pre-cleaning charger 13, a corotron, a scorotron, a solid state charger (solid state charger), a charging roller, or the like is used. All are usable.
As the transfer means, the above charger can be generally used. However, as shown in the figure, a combination of a transfer charger and a separation charger is effective.
The light source such as the image exposure unit 5 and the charge removal lamp 2 emits light 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). All things 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.
In addition to the steps shown in FIG. 4, the light source and the like are provided with a transfer step, a static elimination step, a cleaning step, or a pre-exposure step that uses light irradiation, so that the photosensitive member is irradiated with light.

The toner developed on the photosensitive member 1 by the developing unit 6 is transferred to the transfer paper 9, but not all is transferred, and some toner remains on the photosensitive member 1. Such toner is removed from the photoreceptor by the fur brush 14 and the cleaning brush 15. Cleaning may be performed only with a cleaning brush, and a known brush such as a fur brush or a mag fur brush is used as the cleaning brush.
When the electrophotographic photosensitive member is positively (negatively) charged and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. 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.
A known method is applied to the developing unit, and a known method is also used for the charge eliminating unit.

The image forming apparatus of the present invention can include an abutting member that contacts and rubs against the electrophotographic photosensitive member. As the pressed contact member, a contact member for rubbing the exposed portion of the fluororesin fine particles may be provided, a contact charging member such as a charging roller, a cleaning member such as a cleaning blade or a cleaning brush, a transfer A mechanism for applying pressure to a member generally used in an image forming apparatus such as a transfer member such as a belt or an intermediate transfer belt may be provided. Here, a case where the surface of the photoreceptor is rubbed with the cleaning brush 15 will be described as an example. The cleaning blade is preferable because it has a great effect of rubbing the entire surface of the photosensitive member while pressing the surface of the photosensitive member with a substantially uniform pressure so that the fluororesin fine particles are uniformly attached to the surface.
When the fluororesin is coated with the cleaning blade, various conditions of the cleaning blade include a blade contact angle of 10 to 30 degrees, a contact pressure of 0.3 to 4 g / mm, and a rubber hardness of urethane rubber used as the blade of 60 to 70 degrees. The range of impact resilience of 30 to 70%, Young's modulus of 30 to 60 kgf / cm ² , thickness of 1.5 to 3.0 mm, free length of 7 to 12 mm, and the amount of biting into the photoreceptor of the blade edge is preferably 0.2 to 2 mm. It is.

図５には、本発明による電子写真プロセスの別の例を示す。感光体２１は少なくとも感光層を有し、更に最表面層にフィラーを含有しており、駆動ローラ２２ａ，２２ｂにより駆動され、帯電器２３による帯電、光源２４による像露光、現像（図示せず）、転写チャージャ２５を用いる転写、光源２６によるクリーニング前露光、クリーニングブラシ２７によるクリーニング、光源２８による除電が繰返し行なわれる。図５においては、感光体２１（勿論この場合は支持体が透光性である）に支持体側よりクリーニング前露光の光照射が行なわれる。
以上の図示した電子写真プロセスは、本発明における実施形態を例示するものであって、他の実施形態も可能であることは言うまでもない。例えば、図５において支持体側よりクリーニング前露光を行っているが、これは感光層側から行ってもよいし、また、像露光、除電光の照射を支持体側から行ってもよい。
一方、光照射工程は、像露光、クリーニング前露光、除電露光が図示されているが、他に、転写前露光、像露光のプレ露光、及びその他公知の光照射工程を設けて、感光体に光照射を行うこともできる。
以上に示すような画像形成手段は、複写装置、ファクシミリ、プリンター内に固定して組み込んでもよいが、プロセスカートリッジの形でそれらの装置内に組み込んでもよい。プロセスカートリッジとは、感光体を内蔵し、他に帯電手段、露光手段、現像手段、転写手段、クリーニング手段、除電手段を含んだ１つの装置（部品）である。プロセスカートリッジの形状等は多種多様であるが、一般的な例として、図６に示すものが挙げられる。感光体１６は、導電性支持体上に少なくとも感光層を有し、かつ最表面層にフィラーを含有する。

FIG. 5 shows another example of the electrophotographic process according to the present invention. The photoreceptor 21 has at least a photosensitive layer, and further contains a filler on the outermost surface layer. The photoreceptor 21 is driven by driving rollers 22a and 22b, is charged by a charger 23, is exposed to an image by a light source 24, and is developed (not shown). The transfer using the transfer charger 25, the exposure before cleaning with the light source 26, the cleaning with the cleaning brush 27, and the charge removal with the light source 28 are repeated. In FIG. 5, the photoconductor 21 (of course, the support is translucent in this case) is irradiated with pre-cleaning exposure light from the support side.
The above illustrated electrophotographic process exemplifies an embodiment of the present invention, and it goes without saying that other embodiments are possible. For example, in FIG. 5, the pre-cleaning exposure is performed from the support side, but this may be performed from the photosensitive layer side, or image exposure and neutralization light irradiation may be performed from the support side.
On the other hand, in the light irradiation process, image exposure, pre-cleaning exposure, and static elimination exposure are illustrated. In addition, a pre-transfer exposure, a pre-exposure of image exposure, and other known light irradiation processes are provided on the photoconductor. Light irradiation can also be performed.
The image forming means as described above 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. A process cartridge is a single device (part) that contains a photosensitive member and includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit. The process cartridge has various shapes and the like, and a general example is shown in FIG. The photoreceptor 16 has at least a photosensitive layer on a conductive support, and contains a filler in the outermost surface layer.

An embodiment of an electrophotographic printer (hereinafter simply referred to as a printer) will be described as a full-color image forming apparatus to which the present invention is applied.
FIG. 7 is a schematic configuration diagram of the printer according to the present embodiment. In the figure, a photosensitive member 56 as a latent image carrier is rotated counterclockwise in the figure, and its surface is uniformly charged by a charging charger 53 using a corotron or a scorotron, and then a laser optical (not shown). The electrostatic latent image is carried by scanning with the laser beam L emitted from the apparatus. Since this scanning is performed based on single-color image information obtained by decomposing a full-color image into yellow, magenta, cyan, and black color information, a single-color electrostatic image of yellow, magenta, cyan, or black is formed on the photosensitive drum 56. A latent image is formed. A revolver developing unit 50 is disposed on the left side of the photosensitive drum 56 in the drawing. This has a yellow developing unit, a magenta developing unit, a cyan developing unit, and a black developing unit in a rotating drum-shaped casing, and each developing unit is sequentially moved to a developing position facing the photosensitive drum 56 by rotation. Move. The yellow developer, magenta developer, cyan developer, and black developer are for developing an electrostatic latent image by attaching yellow toner, magenta toner, cyan toner, and black toner, respectively. An electrostatic latent image for yellow, magenta, cyan, and black is sequentially formed on the photosensitive drum 56, and these images are sequentially developed by the developing units of the revolver developing unit 50, so that a yellow toner image, a magenta toner image, and a cyan toner are developed. A toner image and a black toner image are obtained.

An intermediate transfer unit is disposed on the downstream side of the photosensitive drum 56 from the development position. This is because the intermediate transfer belt 58 stretched by a tension roller 59a, an intermediate transfer bias roller 57 as a transfer means, a secondary transfer backup roller 59b, and a belt drive roller 59c is driven by rotation of the belt drive roller 59c. Move endlessly clockwise. The yellow toner image, magenta toner image, cyan toner image, and black toner image developed on the photosensitive drum 56 enter an intermediate transfer nip where the photosensitive drum 56 and the intermediate transfer belt 58 are in contact with each other. Then, while being influenced by the bias from the intermediate transfer bias roller 57, the toner image is superimposed and transferred onto the intermediate transfer belt 58 to form a four-color superimposed toner image.
The surface of the photosensitive drum 56 that has passed through the intermediate transfer nip with the rotation is cleaned of the transfer residual toner by the drum cleaning unit 55. The drum cleaning unit 55 cleans the transfer residual toner by a cleaning roller to which a cleaning bias is applied, but a cleaning brush made of a fur brush, a mag fur brush, or a cleaning blade may be used. .
The surface of the photosensitive drum 56 from which the transfer residual toner has been cleaned is discharged by the discharging lamp 54. As the charge removal lamp 54, a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), an electroluminescence (EL), or the like is used. A semiconductor laser is used as the light source of the laser optical device. About these emitted lights, you may make it use only a desired wavelength range by various 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.

On the other hand, the registration roller pair 61 sandwiching the transfer paper 60 sent from a paper feed cassette (not shown) between the two rollers can superimpose the transfer paper 60 on the four-color superimposed toner image on the intermediate transfer belt 58. It feeds toward the secondary transfer nip at the timing. The four-color superimposed toner image on the intermediate transfer belt 58 is secondarily transferred collectively onto the transfer paper 60 under the influence of the secondary transfer bias from the paper transfer bias roller 63 in the secondary transfer nip. A full color image is formed on the transfer paper 60 by this secondary transfer. The transfer paper 60 on which the full-color image is formed is sent to the transport belt 64 by the transfer belt 62. The conveyor belt 64 feeds the transfer paper 60 received from the transfer unit into the fixing unit 65. The fixing unit 65 conveys the transferred transfer paper 60 while being sandwiched between fixing nips formed by contact between the heating roller and the backup roller. The full-color image on the transfer paper 60 is fixed on the transfer paper 60 under the influence of heating from the heating roller and pressure applied in the fixing nip.
Although not shown, a bias for adsorbing the transfer paper 60 is applied to the transfer belt 62 and the conveyance belt 64. In addition, a paper neutralization charger that neutralizes the transfer paper 60 and three belt neutralization chargers that neutralize each belt (intermediate transfer belt 58, transfer belt 62, and conveyance belt 64) are provided. The intermediate transfer unit also includes a belt cleaning unit having the same configuration as that of the drum cleaning unit 55, thereby cleaning the transfer residual toner on the intermediate transfer belt 58.

FIG. 8 shows a modification of the image forming apparatus according to this embodiment. This apparatus is a tandem type image forming apparatus having an intermediate transfer belt 87, and includes photosensitive drums 80Y, 80M, 80C, and 80Bk for each color, instead of sharing the photosensitive drum 80 for each color. The drum cleaning unit 85, the charge removal lamp 83, and the charging roller 84 for uniformly charging the drum are also provided for each color. In the printer shown in FIG. 7, the charging charger 53 is provided as the drum uniform charging means, but in this apparatus, the charging roller 84 is provided.
In the tandem system, latent image formation and development of each color can be performed in parallel, so that the image formation speed can be made much faster than the revolver system.

  According to the present invention, there is provided a photoconductor that has high durability, suppresses image deterioration such as a residual image due to increase in residual potential or decrease in charge, and can stably obtain a high-quality image even for repeated use over a long period of time. Can be provided. In addition, by using these photoconductors, it is not necessary to replace the photoconductors, and it is possible to reduce the size of the apparatus due to high-speed printing or reducing the diameter of the photoconductor, and to stably obtain high-quality images even during repeated use. The electrophotographic method, the electrophotographic apparatus, and the electrophotographic process cartridge can be provided.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not restrict | limited by these Examples. “Parts” are all parts by weight.

◎電荷輸送層塗工液
・ポリカーボネート（Ｚポリカ、帝人化成製）：８部
・下記〔化１６〕の電荷輸送物質：１０部
・テトラヒドロフラン：１００部

更に、電荷輸送層上に、下記組成の保護層塗工液を高速液衝突分散装置（装置名：アルティマイザーＨＪＰ−２５００５、スギノマシン社製）において、１００ＭＰａ圧力下、３０分間循環し、その後、超音波を１０分間照射して調整し、スプレー塗工［スプレーガン：ピースコンＰＣ３０８、オリンポス社製、エア圧：２ｋｇｆ／ｃｍ^２］を行い、１３０℃６０分間乾燥して約５μｍの保護層を形成し、電子写真感光体１を作製した。
◎保護層塗工液
・パーフロロアルコキシ樹脂粒子（ＭＰＥ−０５６、三井フロロケミカル製）
：５．５部
・分散助剤（モディパーＦ２１０、日本油脂製）：１．０部
・例示化合物４：０．４部
・ポリカーボネート（Ｚポリカ、帝人化成製）：４部
・テトラヒドロフラン：２００部
・シクロヘキサノン：６０部 Example 1
An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following composition on an aluminum cylinder are sequentially applied by dip coating and then dried to form an undercoat layer having a thickness of 3.5 μm. A charge generation layer having a thickness of 0.2 μm and a charge transport layer having a thickness of 22 μm were formed.
◎ Undercoat layer coating liquid ・ Titanium dioxide powder (Tyveel CR-EL, manufactured by Ishihara Sangyo): 400 parts ・ Melamine resin (Super Becamine G-821-60, manufactured by Dainippon Ink & Chemicals, Inc.)
: 65 parts ・ Alkyd resin (Beckolite M6401-50, manufactured by Dainippon Ink & Chemicals, Inc.)
: 120 parts ・ 2-butanone: 400 parts ◎ charge generation layer coating solution ・ bisazo pigment of the following [Chemical Formula 15 ]: 12 parts ・ polyvinyl butyral: 5 parts ・ 2-butanone: 200 parts ・ cyclohexanone: 400 parts

Charge transport layer coating solution Polycarbonate (Z Polyca, manufactured by Teijin Chemicals): 8 parts Charge transport material of the following [Chemical Formula 16 ]: 10 parts Tetrahydrofuran: 100 parts

Furthermore, on the charge transport layer, a protective layer coating solution having the following composition was circulated for 30 minutes under a pressure of 100 MPa in a high-speed liquid collision dispersion device (device name: Ultimateizer HJP-25005, manufactured by Sugino Machine Co., Ltd.). Adjust by irradiating with ultrasonic waves for 10 minutes, spray coating [spray gun: Peacecon PC308, manufactured by Olympos, air pressure: 2 kgf / cm ² ], dry at 130 ° C. for 60 minutes to form a protective layer of about 5 μm Thus, an electrophotographic photoreceptor 1 was produced.
◎ Protective layer coating solution ・ Perfluoroalkoxy resin particles (MPE-056, manufactured by Mitsui Fluorochemicals)
: 5.5 parts-Dispersing aid (Modiper F210, manufactured by NOF Corporation): 1.0 parts-Exemplified compound 4: 0.4 parts-Polycarbonate (Z Polyca, manufactured by Teijin Chemicals): 4 parts-Tetrahydrofuran: 200 parts- Cyclohexanone: 60 parts

Example 2
An electrophotographic photosensitive member 2 was produced in the same manner as in Example 1 except that the protective layer coating solution was changed to the following composition.
◎ Protective layer coating solution ・ Perfluoroalkoxy resin particles (MPE-056, manufactured by Mitsui Fluorochemicals)
: 3.3 parts-Dispersing aid (Modiper F210, manufactured by NOF Corporation) 1.0 parts-Exemplified compound 4: 0.4 parts-Polycarbonate (Z Polyca, manufactured by Teijin Chemicals): 6.4 parts-Tetrahydrofuran: 200 parts・ Cyclohexanone: 60 parts

Example 3
An electrophotographic photosensitive member 3 was produced in the same manner as in Example 1 except that the protective layer coating solution was changed to the following composition.
◎ Protective layer coating solution ・ Perfluoroalkoxy resin particles (MPE-056, manufactured by Mitsui Fluorochemicals)
: 7.4 parts-Dispersing aid (Modiper F210, manufactured by NOF Corporation) 1.0 part-Exemplified compound 4: 0.4 parts-Polycarbonate (Z Polyca, manufactured by Teijin Chemicals): 2.3 parts-Tetrahydrofuran: 200 parts・ Cyclohexanone: 60 parts

Comparative Example 1
A comparative electrophotographic photosensitive member 1 was produced in the same manner as in Example 1 except that the protective layer coating solution was changed to the following composition.
◎ Protective layer coating solution ・ Perfluoroalkoxy resin particles (MPE-056, manufactured by Mitsui Fluorochemicals)
: 3.0 parts-Dispersing aid (Modiper F210, manufactured by NOF Corporation)-1.0 parts-Exemplified compound 4: 0.4 parts-Polycarbonate (Z Polyca, manufactured by Teijin Chemicals): 6.7 parts-Tetrahydrofuran: 200 parts・ Cyclohexanone: 60 parts

Comparative Example 2
A comparative electrophotographic photosensitive member 2 was produced in the same manner as in Example 1 except that the protective layer coating solution was changed to the following composition.
◎ Protective layer coating solution ・ Perfluoroalkoxy resin particles (MPE-056, manufactured by Mitsui Fluorochemicals)
: 7.8 parts-Dispersing aid (Modiper F210, manufactured by NOF Corporation)-1.0 parts-Exemplified compound 4: 0.4 parts-Polycarbonate (Z Polyca, manufactured by Teijin Chemicals): 1.9 parts-Tetrahydrofuran: 200 parts・ Cyclohexanone: 60 parts

Comparative Example 3
A comparative electrophotographic photosensitive member 3 was produced in the same manner as in Example 1 except that the protective layer coating solution was changed to the following composition.
◎ Protective layer coating solution ・ Perfluoroalkoxy resin particles (MPE-056, manufactured by Mitsui Fluorochemicals)
: 5.5 parts-Dispersing aid (Modiper F210, manufactured by Nippon Oil & Fats) 1.0 part-Polycarbonate (Z Polyca, manufactured by Teijin Chemicals): 4.2 parts-Tetrahydrofuran: 200 parts-Cyclohexanone: 60 parts

Example 4
An electrophotographic photosensitive member 4 was produced in the same manner as in Example 1 except that the perfluoroalkoxy resin particles in the protective layer coating solution were changed to tetrafluoroethylene resin particles (Lublon L-2, manufactured by Daikin). .

Examples 5-10
Electrophotographic photosensitive members 5 to 10 were produced in the same manner as in Example 1 except that the exemplified compound 4 in the protective layer coating solution was changed to the compounds shown in Table 2 .

Comparative Example 4
A comparative electrophotographic photoreceptor 4 was produced in the same manner as in Example 1 except that the exemplified compound 4 in the protective layer coating solution was changed to the compound of the following [Chemical Formula 17 ].

Comparative Example 5
A comparative electrophotographic photoreceptor 5 was produced in the same manner as in Example 1 except that the exemplified compound 4 in the protective layer coating solution was changed to the compound of the following [Chemical Formula 18 ].

<Toner Production Example 1>
(1) Preparation of monomer composition-Styrene monomer 70 parts-N-butyl methacrylate 30 parts-Polystyrene 5 parts-3,5-di-tert-butylsalicylic acid zinc salt 2 parts-Carbon black 6 parts The monomer mixture was dispersed and mixed with a ball mill for 24 hours to prepare a monomer composition.
(2) Granulation, polymerization A flask equipped with a stirrer, a thermometer, an inert gas introduction tube, and a porous glass tube with a pore diameter of 110,000 kg, a pore volume of 0.42 cc / g, 10φ × 50 mm, 2% 400 ml of an aqueous polyvinyl alcohol solution was taken and stirred at room temperature while feeding nitrogen gas to replace oxygen in the reaction vessel with nitrogen.
Next, 1.56 g of azobisisobutylnitrile was added to 113 g of the monomer composition of (1) and dissolved by stirring, and then passed through a porous glass tube using a pump and added to the aqueous polyvinyl alcohol solution. A mixture of polyvinyl alcohol and the monomer composition was circulated at a rate of about 120 ml / min for 2 hours using the pump and the porous glass tube, and then the internal temperature was set to 70 ° C. and polymerized for 8 hours.
After cooling to room temperature and allowing to stand overnight, the supernatant was removed, water was added and the mixture was stirred for 1 hour, then filtered and dried to obtain a toner. When the particle diameter of this toner was measured with a Coulter counter, the average particle diameter was 8.5 μm, and the particles in the range of 5 to 0 μm were 95% of the total, showing a very narrow particle size distribution.

<Evaluation Example 1>
The suspension containing the toner particles obtained in Toner Production Example 1 is passed through an imaging unit detection zone on a flat plate, the particle image is optically detected by a CCD camera, and the perimeter of an equivalent circle having the same projected area is obtained. The average circularity, which is a value obtained by dividing by the perimeter of real particles, was evaluated. This value can be measured as an average circularity by a flow type particle image analyzer FPIA-2000. As a specific measurement method, a dispersant is added in 100 to 150 ml of water from which impure solids have been removed in advance. As a surfactant, preferably 0.1 to 0.5 ml of alkylbenzene sulfonate is added, and about 0.1 to 0.5 g of a measurement sample is further added. It is obtained by carrying out dispersion treatment for 1 to 3 minutes and measuring the shape and distribution of toner with the above apparatus at a dispersion concentration of 3000 to 10,000 / μl. As a result of the examination so far, it has been found that a toner having 0.960 or more is effective for forming a high-definition image having a reproducibility with an appropriate density, and more preferably an average circularity of 0.1. 980 to 1.000. The circularity of the toner prepared in Toner Production Example 1 was 0.98.

<Evaluation Example 2> (Secondary particle diameter, coating area ratio)
FE-SEM (S-4200 Scanning Electron Microscope, manufactured by Hitachi, Ltd.) was used for 10 arbitrary observation points on the surfaces of the obtained electrophotographic photoreceptors 1 to 10 and comparative electrophotographic photoreceptors 1 to 5. Using an image processing software (Image-Pro Plus), the number of fluorine fine particles (primary particles and agglomerated secondary particles), and each particle were photographed using an image processing software (Image-Pro Plus). The average diameter, area, and area ratio were analyzed, and the total area ratio of particles having an average diameter of 0.15 to 3 μm was calculated as S1, and the total area ratio of particles having an average diameter of 0.2 to 1.5 μm was calculated as S2.

<Evaluation Example 3> (Surface friction coefficient)
The surface friction coefficients of the obtained electrophotographic photosensitive members 1 to 10 and comparative electrophotographic photosensitive members 1 to 5 were evaluated using the Euler belt method disclosed in JP-A-9-166919. As used herein, the belt is medium-quality high-quality paper, and is stretched around the circumference of the photoconductor, as shown in FIG. A load of 100 g is applied, a force gauge (spring balance) is installed on the other side, the movement of the belt is observed while gradually pulling the force gauge, the load at the start of the movement is read, and the following formula is calculated. In FIG. 9, a load: 100 g weight, a belt: Type 6200 / T / A4 paper / 30 mm width (cut in the direction of the gap), and two double clips are used. In the equation, μ represents a friction coefficient, F represents a tensile force, and W represents a load.
μ = 2 / π × ln (F / W) W = 100 g

<Evaluation Example 4> (Durability Life A)
The obtained electrophotographic photoconductors 1 to 10 and comparative electrophotographic photoconductors 1 to 5 were converted from Ricoh's imgio Color 5100 remodeling machine (imagino Color color toner S [roundness 0.91]), and an image exposure light source of a semiconductor of 655 nm. The laser was replaced with a laser and the lubricant application means was removed, and a total of 100,000 sheets were printed continuously. At that time, the initial image and the image after 100,000 sheets were evaluated. Further, the light portion potential at the initial stage and after printing 100,000 sheets was measured. Further, the amount of wear was evaluated from the difference in film thickness at the initial stage and after printing 100,000 sheets.

<Evaluation Example 5> (Durable Life B)
The obtained electrophotographic photoreceptors 1 to 10 and comparative electrophotographic photoreceptors 1 to 5 were changed to Ricoh's imgio Color 5100 remodeling machine (the toner was changed to that prepared in Production Example 1 and the image exposure light source was a semiconductor laser having a wavelength of 655 nm. In addition, a total of 100,000 sheets were printed continuously, and the initial image and the image after 100,000 sheets were evaluated. Further, the light portion potential at the initial stage and after printing 100,000 sheets was measured. Further, the amount of wear was evaluated from the difference in film thickness at the initial stage and after printing 100,000 sheets.

<Evaluation Example 6> (Durable Life C)
The obtained electrophotographic photoreceptors 1 to 10 and comparative electrophotographic photoreceptors 1 to 5 were mounted on a Ricoh imagoio Color 8100 remodeling machine (the toner was changed to that prepared in Production Example 1), and the total amount was continuously measured. 50,000 sheets were printed, and the initial image and the image after printing 50,000 sheets were evaluated. Further, the light portion potential at the initial stage and after printing 50,000 sheets was measured. Furthermore, the amount of wear was evaluated from the difference in film thickness at the initial stage and after printing 50,000 sheets.

Tables 2 to 4 show the evaluation results of the durable lifetimes A to C.
As can be seen from the evaluation results in Table 2, maintaining a highly stable low surface friction coefficient persistence by incorporating fluororesin fine particles with a volume fraction of 20 to 60% into the outermost surface layer of the photoreceptor. Became possible. Further, the amount of wear was also suppressed, and it was confirmed that the wear resistance was greatly improved. Further, it was confirmed that even after printing 100,000 sheets, the bright portion potential increase was small, and no photoimage was observed on the photoconductor to which a specific antioxidant was added, and a high-quality image was stably obtained. On the other hand, a photoconductor not containing 20 to 60% by volume fraction of fluororesin fine particles (Comparative Examples 1 and 2) , a photoconductor in which no exemplified compound is added (Comparative Example 3), and a compound specified in the present invention Photoreceptors using other compounds (Comparative Examples 4 and 5) caused poor cleaning and occurrence of afterimages.
As can be seen from the evaluation results in Tables 3 to 4 , the same tendency as in Table 2 was observed when the spherical toner was used.

FIG. 3 is a diagram illustrating a layer configuration example of the electrophotographic photosensitive member of the present invention. The figure which shows the other layer structural example of the electrophotographic photoreceptor of this invention. FIG. 5 is a view showing still another layer configuration example of the electrophotographic photosensitive member of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Schematic for demonstrating the electrophotographic process and electrophotographic apparatus of this invention. The figure which shows another example of the electrophotographic process by this invention. The figure which shows the general example of a process cartridge. 1 is a schematic configuration diagram of a full-color image forming apparatus to which the present invention is applied. The schematic block diagram of the modification of the full-color image forming apparatus to which this invention is applied. The figure for demonstrating the measurement means of the surface friction coefficient of the evaluation example 3. FIG.

Explanation of symbols

31 Conductive Support 33 Photosensitive Layer 35 Charge Generation Layer 37 Charge Transport Layer 39 Protective Layer

Claims (10)

In the electrophotographic photosensitive member in which the outermost surface layer of the photosensitive layer formed on the conductive support is a protective layer containing fluororesin fine particles as a solid lubricant, the protective layer has a volume fraction of 20 to 60%. An electrophotographic photoreceptor comprising fluororesin fine particles and at least one compound represented by the following general formula (a):

(In the formula, either one of R ¹ and R ² is a substituted or unsubstituted alkyl group , and the other represents an aromatic hydrocarbon group substituted or unsubstituted by an alkyl group or an alkoxy group. Represents a substituted or unsubstituted aromatic hydrocarbon group.)   An electrophotographic method comprising using the electrophotographic photosensitive member according to claim 1 and repeatedly performing at least charging, image exposure, development, and transfer on the electrophotographic photosensitive member. 3. The electrophotographic method according to claim 2 , wherein an electrostatic latent image is written on the photosensitive member by an LD or an LED at the time of image exposure. Claim 2 or 3 electrophotographic method, wherein the shape of the toner used in the image formation is spherical. An electrophotographic apparatus having a charging roller, a cleaning blade, a cleaning brush, and an intermediate transfer belt is used, and at least one of these members is brought into contact with the surface of the electrophotographic photosensitive member to perform charging, image exposure, development, and transfer. electrophotographic method according to any one of claims 2 to 4, characterized in that repeated. An electrophotographic apparatus comprising at least a charging unit, an image exposure unit, a developing unit, a transfer unit, and the electrophotographic photosensitive member according to claim 1 . 7. The electrophotographic apparatus according to claim 6 , wherein an LD or LED is provided as image exposure means , whereby an electrostatic latent image is written on the photosensitive member. A plurality of electrophotographic photosensitive member, a charging means, a developing means, an electrophotographic apparatus according to claim 6 or 7, wherein it is a tandem type having a transfer means. A plurality of color toners having intermediate transfer means for primary transfer of a toner image developed on an electrophotographic photosensitive member onto an intermediate transfer member and then secondary transfer of the toner image on the intermediate transfer member onto a recording material image by sequentially superimposed on the intermediate transfer member to form a color image, an electrophotographic apparatus according to claim 6 or 7, characterized in that the secondary transfer collectively on a recording material to the color image. A process cartridge for an electrophotographic apparatus, comprising at least one of a charging unit, an exposure unit, a developing unit, a cleaning unit, and a transfer unit and the electrophotographic photosensitive member according to claim 1 .

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