JP2006106719A - Electrophotographic photosensitive member, process cartridge and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photosensitive member having high durability and hardly causing sensitivity decrease even if short wavelength light, particularly light having a wavelength of 380-450 nm is used as exposure light, and to provide a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member. <P>SOLUTION: A surface layer of the electrophotographic photosensitive member contains an aliphatic dicarboxylic acid polyester resin with a weight average molecular weight of ≥80,000 having a specific repeating structural unit. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

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

  Photoconductive materials (charge generating materials and charge transport materials) used for electrophotographic photoreceptors mounted on electrophotographic apparatuses include inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide. Organic photoconductive substances have been actively developed from the viewpoints of pollution-free, high productivity, and ease of material design.

  An electrophotographic photosensitive member (organic electrophotographic photosensitive member) using an organic photoconductive substance is obtained by applying a coating liquid obtained by dissolving and dispersing an organic photoconductive substance or a binder resin in a solvent on a support, Those having a photosensitive layer formed by drying this are usually used. The layer structure of the photosensitive layer is generally a laminate type (normal layer type) in which a charge generation layer and a charge transport layer are laminated in this order from the support side.

  An electrophotographic photoreceptor using an organic photoconductive material has the above-mentioned advantages, but does not satisfy all of the characteristics required as an electrophotographic photoreceptor at a high level. Further improvement in image quality and durability of output images is desired.

  Regarding the improvement of image quality, in recent years, in order to further increase the resolution of the output image, light having a shorter wavelength than conventionally used light is used as exposure light (image exposure light) irradiated to the electrophotographic photosensitive member. Has been proposed (Japanese Patent Laid-Open No. 09-240051 (Patent Document 1), etc.).

  Further, since the transmittance of the layer with respect to the exposure light affects the sensitivity of the electrophotographic photosensitive member, for example, Japanese Patent Application Laid-Open No. 2000-105471 (Patent Document 2) discloses a charge of a stacked type (normal layer type) photosensitive layer. A technique is disclosed in which the transport layer is a layer having a high transmittance with respect to exposure light having a short wavelength. Specifically, by using a compound having a specific structure as a charge transport material and using a polycarbonate resin (bisphenol Z-type polycarbonate) as a binder resin, a charge transport layer having a high transmittance for exposure light with a short wavelength is formed. ing.

On the other hand, with regard to the improvement of durability, polycarbonate resin has been often used as a binder resin for the surface layer of the electrophotographic photosensitive member. However, in recent years, as a binder resin for the surface layer, more than polycarbonate resin. A proposal has been made to further improve the durability of an electrophotographic photosensitive member by using a polyarylate resin having high mechanical strength (Japanese Patent Laid-Open No. 10-039521 (Patent Document 3), etc.). The polyarylate resin is one type of aromatic dicarboxylic acid polyester resin.
JP 09-240051 A JP 2000-105471 A Japanese Patent Laid-Open No. 10-039521

  However, the polyarylate resin disclosed in Japanese Patent Application Laid-Open No. 10-039521 has high mechanical strength, and when this is used for the surface layer of the electrophotographic photosensitive member, the electrophotographic photosensitive member has high durability. However, the layer using the polyarylate resin has a relatively low transmittance for light having a short wavelength, particularly light having a wavelength of 380 to 450 nm, and the sensitivity of the electrophotographic photosensitive member may be lowered. there were.

  On the other hand, the electrophotographic photosensitive member specifically disclosed in Japanese Patent Application Laid-Open No. 2000-105471 has a high transmittance with respect to light of a short wavelength of the surface layer (charge transport layer), and exposure light for improving image quality. However, when using short-wavelength light, the sensitivity is unlikely to decrease, but the surface layer is made of polycarbonate resin, which is inferior in mechanical strength to polyarylate resin. There is no such thing.

  An object of the present invention is an electrophotographic photosensitive member that has high durability and is less susceptible to a decrease in sensitivity even when light having a short wavelength, particularly light having a wavelength of 380 to 450 nm, is used as exposure light, and An object of the present invention is to provide a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

  The present invention relates to an electrophotographic photosensitive member having a support and a photosensitive layer containing a charge generating material and a charge transporting material provided on the support, wherein the surface layer of the electrophotographic photosensitive member has the following formula (1): An electrophotographic photoreceptor comprising an aliphatic dicarboxylic acid polyester resin having a weight average molecular weight of 80000 or more and having a repeating structural unit represented by formula (1).

(In formula (1), R ^{11 to} R ¹⁸ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, or an aryl group. X ¹¹ is a carbon constituting the main chain, which is substituted or unsubstituted. An alkylene group having 3 to 10 atoms, a substituted or unsubstituted cycloalkylene group having 5 to 10 carbon atoms constituting the ring, or a substituted or unsubstituted ring containing 5 to 5 carbon atoms And Y ¹¹ represents a single bond, a group 16 element, or a divalent group having a structure represented by the following formula (2).

(In Formula (2), R ²¹ and R ²² each independently represent a hydrogen atom, an alkyl group, a fluorinated alkyl group, an alkoxy group, or an aryl group, or R ²¹ and R ²² are bonded to each other. A cycloalkylidene group or a fluorenylidene group formed by
The present invention also provides a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

  According to the present invention, an electrophotographic photosensitive member that has high durability and is less likely to cause a decrease in sensitivity even when light having a short wavelength, particularly light having a wavelength of 380 to 450 nm, is used as exposure light, and A process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member can be provided.

  As described above, the electrophotographic photosensitive member of the present invention includes an aliphatic dicarboxylic acid polyester resin having a weight average molecular weight of 80,000 or more having a repeating structural unit represented by the following formula (1) on the surface layer. To do.

In the formula ^{(1), R} 11 ~R ¹⁸ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, or an aryl group. X ¹¹ is a substituted or unsubstituted alkylene group having 3 to 10 carbon atoms constituting the main chain, a substituted or unsubstituted cycloalkylene group having 5 to 10 carbon atoms constituting the ring, or A substituted or unsubstituted bicycloalkylene group having 5 to 10 carbon atoms constituting the ring is shown. Y ¹¹ represents a single bond, a group 16 element, or a divalent group having a structure represented by the following formula (2).

In the above formula (2), R ²¹ and R ²² each independently represent a hydrogen atom, an alkyl group, a fluorinated alkyl group, an alkoxy group, or an aryl group, or R ²¹ and R ²² are bonded to each other. A cycloalkylidene group or a fluorenylidene group formed in the above manner.

Examples of the alkyl group of R ^{11 to} R ^{18 in} the above formula (1) include a methyl group, an ethyl group, a propyl group, a butyl group, and the alkoxy group includes a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Examples of the aryl group include a phenyl group and a naphthyl group. Among these, a methyl group, an ethyl group, a methoxy group, an ethoxy group, and a phenyl group are preferable.

Examples of the substituted or unsubstituted alkylene group having 3 to 10 carbon atoms constituting the main chain of X ¹¹ in the formula (1) include a substituted or unsubstituted propylene group, a substituted or unsubstituted butylene group, Examples include substituted or unsubstituted pentylene group, substituted or unsubstituted hexylene group, substituted or unsubstituted heptylene group, substituted or unsubstituted octylene group, substituted or unsubstituted nonylene group, substituted or unsubstituted decylene group. Among these, a substituted or unsubstituted butylene group, a substituted or unsubstituted pentylene group, a substituted or unsubstituted hexylene group, a substituted or unsubstituted heptylene group, or a substituted or unsubstituted octylene group is preferable.

Further, the substituted or unsubstituted X ¹¹ in the formula (1), The cycloalkylene group having a carbon number of 5 to 10 constituting the ring, a substituted or unsubstituted cyclopentylene group, a substituted or unsubstituted Cyclohexylene group, substituted or unsubstituted cycloheptylene group, substituted or unsubstituted cyclooctylene group, substituted or unsubstituted cyclononylene group, substituted or unsubstituted cyclodecylene group, among these, substituted or unsubstituted A substituted cyclohexylene group is preferred.

Further, the substituted or unsubstituted X ¹¹ in the formula (1), examples of the bicycloalkyl alkylene group having a carbon number of 5 to 10 constituting the ring, a substituted or unsubstituted bicycloalkyl cyclopentylene group, a substituted or unsubstituted A bicyclohexylene group, a substituted or unsubstituted bicycloheptylene group, a substituted or unsubstituted bicyclooctylene group, a substituted or unsubstituted bicyclononylene group, and a substituted or unsubstituted bicyclodecylene group. Among these, a substituted or unsubstituted bicyclodecylene group is preferable, and a 2,5-bicyclo [4.4.0] decylene group is particularly preferable.

  Examples of the substituent that the alkylene group, the cycloalkylene group, and the bicycloalkylene group may have include an alkyl group such as a methyl group, an ethyl group, a propyl group, and a butyl group, a trifluoromethyl group, and a pentafluoroethyl group. And fluorinated alkyl groups such as methoxy groups, ethoxy groups, propoxy groups, and butoxy groups. Among these, methyl groups and trifluoromethyl groups are preferable. An unsubstituted alkylene group, an unsubstituted cycloalkylene group, and an unsubstituted bicycloalkylene group are also preferable.

Group 16 element of Y ¹¹ in the formula (1), an oxygen atom or, is preferably a sulfur atom.

Examples of the alkyl group represented by R ²¹ and R ^{22 in} the above formula (2) include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the fluorinated alkyl group include a trifluoromethyl group and a pentafluoroethyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Examples of the aryl group include a phenyl group and a naphthyl group. Among these, a methyl group, an ethyl group, and the like. Group, propyl group (particularly isopropyl group), trifluoromethyl group, and pentafluoroethylene group are preferable.

Examples of the cycloalkylidene group formed by combining R ²¹ and R ²² in the above formula (2) include a cyclopentylidene group, a cyclohexylidene group, and a cycloheptylidene group. Among these, a cyclohexylidene group is preferable.

Among the repeating structural units represented by the above formula (1), suitable repeating structural units include the following.
- at least one alkyl group ^R 11 ^{to R 18} in the formula (1), an alkoxy group or an aryl group, and ^{those Y 11} is a single bond.
The above mentioned formula (1) as Y ¹¹ in is an oxygen atom or a sulfur atom.
- at least one alkyl group ^R 11 ^{to R 18} in the formula (1), an alkoxy group or an aryl group, ^and a divalent group ^having a structure ^{Y 11} is represented by the formula (2) In addition, R ²¹ and R ²² in the above formula (2) are each independently an alkyl group or a fluorinated alkyl group.
- at least one alkyl group ^R 11 ^{to R 18} in the formula (1), an alkoxy group or an aryl group, ^and a divalent group ^having a structure ^{Y 11} is represented by the formula (2) In addition, R ²¹ and R ²² in the above formula (2) are cyclohexylidene groups formed by combining R ²¹ and R ²² .

  Specific examples of the repeating structural unit represented by the above formula (1) are shown below.

  As described above, the aliphatic dicarboxylic acid polyester resin having a repeating structural unit represented by the above formula (1) used for the surface layer of the electrophotographic photoreceptor of the present invention has a weight average molecular weight of 80000 or more. Of the aliphatic dicarboxylic acid polyester resins having a repeating structural unit represented by the above formula (1), those having a weight average molecular weight of less than 80000 have low mechanical strength and are insufficient for improving the durability of the electrophotographic photosensitive member. It is. Furthermore, it is preferable that a weight average molecular weight is 90000 or more.

  On the other hand, if the molecular weight of the aliphatic dicarboxylic acid polyester resin having the repeating structural unit represented by the above formula (1) is too large, the coating property of the coating solution containing this may deteriorate, so the above formula (1) The weight average molecular weight of the aliphatic dicarboxylic acid polyester resin having a repeating structural unit represented by is preferably 400,000 or less, more preferably 300,000 or less.

  In addition, the weight average molecular weight in this invention is a polystyrene conversion weight average molecular weight.

  The aliphatic dicarboxylic acid polyester resin having a repeating structural unit represented by the above formula (1) used for the surface layer of the electrophotographic photoreceptor of the present invention is synthesized by a transesterification method between a dicarboxylic acid ester and a compound having a hydroxyl group. It can also be synthesized by a polymerization reaction between a divalent acid halide such as dicarboxylic acid halide and a compound having a hydroxyl group such as bisphenol, but the weight average molecular weight is within the above range. Is preferably synthesized by the latter synthesis method.

(Synthesis example)
Below, the synthesis method of the aliphatic dicarboxylic acid polyester resin whose weight average molecular weight which has a repeating structural unit shown by said Formula (1-5) and whose weight average molecular weight is 80000 or more is shown as a synthesis example.

  The following formula (1-5-1)

A dicarboxylic acid halide (suberic acid chloride) having a structure represented by is dissolved in dichloromethane to prepare a suberic acid chloride solution.

  In addition to the suberic acid chloride solution, the following formula (1-5-2)

Bisphenol (tetramethylbiphenol) having a structure represented by is dissolved in a 10% aqueous sodium hydroxide solution, and tributylbenzylammonium chloride as a polymerization catalyst was added thereto and stirred to prepare a tetramethylbiphenol solution.

  Next, the suberic acid chloride solution was added to the tetramethylbiphenol solution with stirring to initiate polymerization. The polymerization was carried out for 3 hours while maintaining the reaction temperature at 25 ° C. or lower and stirring.

  Thereafter, the polymerization reaction was terminated by the addition of acetic acid, and washing with water was repeated until the aqueous phase became neutral.

  After washing, the solution is dropped into methanol with stirring to precipitate a polymer, and this polymer is vacuum-dried to obtain an aliphatic dicarboxylic acid polyester resin having a repeating structural unit represented by the above formula (1-5). It was. The aliphatic dicarboxylic acid polyester resin had a weight average molecular weight of 150,000.

  In the present invention, the weight average molecular weight of the resin is measured as follows according to a conventional method.

  That is, the measurement target resin is put in tetrahydrofuran and allowed to stand for several hours, and then mixed well with the measurement target resin and tetrahydrofuran while shaking (mixed until the measurement target resin is no longer united), and then allowed to stand for 12 hours or more. .

  Then, the sample processed filter Mysholy disk H-25-5 made by Tosoh Corporation was used as a sample for GPC (gel permeation chromatography).

  Next, the column is stabilized in a heat chamber at 40 ° C., tetrahydrofuran is flowed through the column at this temperature at a flow rate of 1 ml / min, 10 μl of GPC sample is injected, and the weight average molecular weight of the measurement target resin Was measured. A column TSKgel Super HM-M manufactured by Tosoh Corporation was used as the column.

  In the measurement of the weight average molecular weight of the measurement target resin, the molecular weight distribution of the measurement target resin was calculated from the relationship between the logarithmic value of the calibration curve prepared by several kinds of monodisperse polystyrene standard samples and the count number. Ten standard polystyrene samples for preparing a calibration curve were used from Aldrich monodisperse polystyrene having a molecular weight of 800 to 2,000,000. An RI (refractive index) detector was used as the detector.

  Next, the configuration of the electrophotographic photosensitive member of the present invention will be described.

  As described above, the electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor having a support and a photosensitive layer provided on the support.

  The photosensitive layer is separated into a charge generating layer containing a charge generating material and a charge transporting layer containing a charge transporting material even if it is a single layer type photosensitive layer containing the charge transporting material and the charge generating material in the same layer. A laminated type (functional separation type) photosensitive layer may be used, but a laminated type photosensitive layer is preferred from the viewpoint of electrophotographic characteristics. The laminated photosensitive layer has a normal layer type photosensitive layer laminated in the order of the charge generation layer and the charge transport layer from the support side, and a reverse layer type photosensitive layer laminated in the order of the charge transport layer and the charge generation layer from the support side. However, a normal photosensitive layer is preferred from the viewpoint of electrophotographic characteristics. Further, the charge generation layer may have a laminated structure, and the charge transport layer may have a laminated structure.

  Further, a protective layer may be provided on the photosensitive layer for the purpose of protecting the photosensitive layer.

  FIG. 1 shows an example of the layer structure of the electrophotographic photosensitive member of the present invention.

  In the electrophotographic photosensitive member having a layer structure shown in FIG. 1A, a single-layer type photosensitive layer 104 containing a charge generating substance and a charge transporting substance is provided on a support 101. In the electrophotographic photosensitive member having the layer structure shown in FIG. 1A, the single-layer type photosensitive layer 104 is a surface layer, and the single-layer type photosensitive layer 104 has a repeating structure represented by the above formula (1). It contains an aliphatic dicarboxylic acid polyester resin having a unit and a weight average molecular weight of 80,000 or more.

  In the electrophotographic photosensitive member having the layer structure shown in FIG. 1B, a charge generation layer 1041 containing a charge generation material is provided on a support 101, and a charge transport material is contained on the charge generation layer 1042. A charge transport layer 1042 is provided. That is, the photosensitive layer 104 of the electrophotographic photosensitive member having the layer structure shown in FIG. 1B is a stacked type (normal layer type) photosensitive layer having the charge generation layer 1041 and the charge transport layer 1042. In the electrophotographic photosensitive member having the layer structure shown in FIG. 1B, the charge transport layer 1042 is a surface layer, and the charge transport layer 1042 has a weight having a repeating structural unit represented by the above formula (1). An aliphatic dicarboxylic acid polyester resin having an average molecular weight of 80,000 or more is contained.

  Further, as shown in FIGS. 1C and 1D, a protective layer 105 may be provided on the photosensitive layer 104 as a surface layer of the electrophotographic photosensitive member. In the electrophotographic photosensitive member having the layer structure shown in FIGS. 1C and 1D, the protective layer 105 is a surface layer, and the protective layer 105 has a repeating structural unit represented by the above formula (1). It contains an aliphatic dicarboxylic acid polyester resin having a weight average molecular weight of 80,000 or more.

  In addition, in any layer configuration, the surface layer of the electrophotographic photosensitive member, that is, the layer located on the outermost surface of the electrophotographic photosensitive member has a weight average molecular weight having the repeating structural unit represented by the above formula (1). May contain an aliphatic dicarboxylic acid polyester resin of 80000 or more.

  As a support body, what is necessary is just to have electroconductivity (electroconductive support body), For example, metal (alloy-made) support bodies, such as aluminum, aluminum alloy, and stainless steel, can be used. Moreover, the said metal support body and plastic support body which have a layer in which aluminum, an aluminum alloy, an indium oxide tin oxide alloy etc. were formed into a film by vacuum deposition can also be used. In addition, a support in which conductive particles such as carbon black, tin oxide particles, titanium oxide particles, and silver particles are impregnated into plastic or paper together with an appropriate binder resin, or a plastic support having a conductive binder resin, etc. Can also be used. In addition, examples of the shape of the support include a cylindrical shape and a belt shape, and a cylindrical shape is preferable.

  The surface of the support may be subjected to cutting treatment, roughening treatment, alumite treatment, etc. for the purpose of preventing interference fringes due to scattering of laser light or the like.

  Between the support and the photosensitive layer (charge generation layer, charge transport layer) or an intermediate layer described later, there is a conductive layer for the purpose of preventing interference fringes due to scattering of laser light or the like and covering the scratches on the support. It may be provided.

  The conductive layer can be formed by dispersing conductive particles such as carbon black, metal particles, and metal oxide particles in a binder resin.

  The thickness of the conductive layer is preferably 1 to 40 μm, and more preferably 2 to 20 μm.

  Further, an intermediate layer having a barrier function or an adhesive function may be provided between the support or the conductive layer and the photosensitive layer (charge generation layer, charge transport layer). The intermediate layer is formed for the purpose of improving the adhesion of the photosensitive layer, improving the coating property, improving the charge injection property from the support, and protecting the photosensitive layer from electrical breakdown.

  The intermediate layer is acrylic resin, allyl resin, alkyd resin, ethyl cellulose resin, ethylene-acrylic acid copolymer, epoxy resin, casein resin, silicone resin, gelatin resin, nylon, phenol resin, butyral resin, polyacrylate resin, polyacetal resin, polyamide Imide resin, polyamide resin, polyaryl ether resin, polyimide resin, polyurethane resin, polyester resin, polyethylene resin, polycarbonate resin, polystyrene resin, polysulfone resin, polyvinyl alcohol resin, polybutadiene resin, polypropylene resin, urea resin, etc., oxidation It can be formed using a material such as aluminum.

  The thickness of the intermediate layer is preferably 0.05 to 5 μm, and more preferably 0.3 to 1 μm.

  Examples of the charge generating material used in the electrophotographic photoreceptor of the present invention include azo pigments such as monoazo, disazo, and trisazo, phthalocyanine pigments such as metal phthalocyanine and nonmetal phthalocyanine, indigo pigments such as indigo and thioindigo, Perylene pigments such as perylene anhydride, perylene imide, polycyclic quinone pigments such as anthraquinone, pyrenequinone, dibenzpyrenequinone, squarylium dyes, pyrylium and thiapyrylium salts, triphenylmethane dyes, selenium, Inorganic substances such as selenium-tellurium and amorphous silicon, quinacridone pigments, azurenium salt pigments, cyanine dyes such as quinocyanine, anthanthrone pigments, pyranthrone pigments, xanthene dyes, quinoneimine dyes, Dyes and, and cadmium sulfide, zinc oxide and the like. These charge generation materials may be used alone or in combination of two or more.

  When the photosensitive layer is a laminated photosensitive layer and the charge generation layer is not a surface layer of an electrophotographic photosensitive member, examples of the binder resin used for the charge generation layer include acrylic resins, allyl resins, and alkyd resins. , Epoxy resin, diallyl phthalate resin, silicone resin, styrene-butadiene copolymer, nylon, phenol resin, butyral resin, benzal resin, polyacrylate resin, polyacetal resin, polyamideimide resin, polyamide resin, polyaryl ether resin, polyarylate resin, Polyimide resin, polyurethane resin, polyester resin, polyethylene resin, polycarbonate resin, polystyrene resin, polysulfone resin, polyvinyl acetal resin, polybutadiene resin, polypropylene resin, methacrylic resin, urea resin Vinyl chloride - vinyl acetate copolymer, vinyl acetate resins, and vinyl chloride resins. In particular, a butyral resin is preferable. These can be used singly or in combination of two or more as a mixture or copolymer.

  When the charge generation layer is a surface layer of an electrophotographic photosensitive member, the charge generation layer has an aliphatic having a weight average molecular weight of at least 80000 having at least a repeating structural unit represented by the above formula (1) as a binder resin. A dicarboxylic acid polyester resin is used. Other resins exemplified above can be used in combination as long as the effects of the present invention are not impaired. In that case, the weight-average molecular weight having the repeating structural unit represented by the above formula (1) in the charge generation layer is The ratio of the aliphatic dicarboxylic acid polyester resin of 80000 or more is preferably 50% by mass or more with respect to the total mass of the binder resin contained in the charge generation layer.

  The charge generation layer can be formed by applying a charge generation layer coating solution obtained by dispersing a charge generation material together with a binder resin and a solvent and drying the coating solution. Examples of the dispersion method include a method using a homogenizer, an ultrasonic disperser, a ball mill, a sand mill, a roll mill, a vibration mill, an attritor, a liquid collision type high-speed disperser, and the like. The ratio between the charge generating material and the binder resin is preferably in the range of 1: 0.3 to 1: 4 (mass ratio).

  The solvent used in the coating solution for the charge generation layer is selected from the solubility and dispersion stability of the binder resin and charge generation material to be used. As the organic solvent, alcohol, sulfoxide, ketone, ether, ester, aliphatic Examples thereof include halogenated hydrocarbons and aromatic compounds.

  The thickness of the charge generation layer is preferably 5 μm or less, and more preferably 0.1 to 2 μm.

  In addition, various sensitizers, antioxidants, ultraviolet absorbers, plasticizers, and the like can be added to the charge generation layer as necessary.

  Examples of the charge transport material used in the electrophotographic photoreceptor of the present invention include triarylamine compounds, hydrazone compounds, styryl compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, and triarylmethane compounds. These charge transport materials may be used alone or in combination of two or more.

  When the photosensitive layer is a laminated photosensitive layer and the charge transport layer is not a surface layer of an electrophotographic photoreceptor, examples of the binder resin used for the charge transport layer include acrylic resins, acrylonitrile resins, and allyl resins. , Alkyd resin, epoxy resin, silicone resin, nylon, phenolic resin, phenoxy resin, butyral resin, polyacrylamide resin, polyacetal resin, polyamideimide resin, polyamide resin, polyaryl ether resin, polyarylate resin, polyimide resin, polyurethane resin, Polyester resin, polyethylene resin, polycarbonate resin, polystyrene resin, polysulfone resin, polyvinyl butyral resin, polyphenylene oxide resin, polybutadiene resin, polypropylene resin, methacrylic resin, urea resin, salt Vinyl resins, vinyl acetate resins. In particular, polyarylate resin, polycarbonate resin and the like are preferable. These can be used singly or in combination of two or more as a mixture or copolymer.

  When the charge transport layer is a surface layer of an electrophotographic photoreceptor, the charge transport layer includes an aliphatic having a weight average molecular weight of 80000 or more having at least a repeating structural unit represented by the above formula (1) as a binder resin. A dicarboxylic acid polyester resin is used. Other resins exemplified above can be used in combination as long as the effects of the present invention are not impaired. In that case, the weight average molecular weight having the repeating structural unit represented by the above formula (1) in the charge transport layer is The proportion of the aliphatic dicarboxylic acid polyester resin of 80000 or more is preferably 50% by mass or more based on the total mass of the binder resin contained in the charge transport layer.

  The charge transport layer can be formed by applying a charge transport layer coating solution obtained by dissolving a charge transport material and a binder resin in a solvent and drying it. The ratio between the charge transport material and the binder resin is preferably in the range of 2: 1 to 1: 2 (mass ratio).

  Solvents used in the coating solution for the charge transport layer include ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as toluene and xylene, ethers such as 1,4-dioxane and tetrahydrofuran, Hydrocarbons substituted with halogen atoms such as chlorobenzene, chloroform and carbon tetrachloride are used.

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

  In addition, an antioxidant, an ultraviolet absorber, a plasticizer, and the like can be added to the charge transport layer as necessary.

  When the photosensitive layer is a single-layer type photosensitive layer and the single-layer type photosensitive layer is not a surface layer of an electrophotographic photosensitive member, the single-layer type photosensitive layer contains the charge generating substance and the charge transporting substance. It can be formed by applying a coating solution for a single-layer type photosensitive layer obtained by dispersing together with the binder resin and the solvent and drying it.

  When the photosensitive layer is a single-layer type photosensitive layer and the single-layer type photosensitive layer is not a surface layer of an electrophotographic photosensitive member, the various resins described above are used as the binder resin for the single-layer type photosensitive layer. Can be used.

  When the single-layer type photosensitive layer is a surface layer of an electrophotographic photosensitive member, the single-layer type photosensitive layer has a weight average molecular weight of at least 80000 having a repeating structural unit represented by the above formula (1) as a binder resin. The above aliphatic dicarboxylic acid polyester resins are used. Other resins exemplified above can be used in combination as long as the effects of the present invention are not impaired. In that case, the weight average having the repeating structural unit represented by the above formula (1) in the single-layer type photosensitive layer is used. The proportion of the aliphatic dicarboxylic acid polyester resin having a molecular weight of 80,000 or more is preferably 50% by mass or more based on the total mass of the binder resin contained in the single-layer type photosensitive layer.

  Further, as described above, a protective layer may be provided on the photosensitive layer for the purpose of protecting the photosensitive layer. The protective layer can be formed by applying a protective layer coating solution obtained by dissolving a binder resin in a solvent and drying the coating solution.

  For the protective layer serving as the surface layer of the electrophotographic photosensitive member, at least an aliphatic dicarboxylic acid polyester resin having a weight average molecular weight of 80000 or more and having a repeating structural unit represented by the above formula (1) is used as a binder resin. . Other resins exemplified above may be used in combination as long as the effects of the present invention are not impaired. In that case, the weight average molecular weight having the repeating structural unit represented by the above formula (1) in the protective layer is 80,000. The proportion of the aliphatic dicarboxylic acid polyester resin is preferably 50% by mass or more based on the total mass of the binder resin contained in the protective layer.

  The thickness of the protective layer is preferably 0.5 to 10 μm, and particularly preferably 1 to 5 μm.

  When applying the coating liquid for each of the above layers, for example, a coating method such as a dip coating method (dip coating method), a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, a blade coating method, or the like should be used. Can do.

  FIG. 2 shows an example of a schematic configuration of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.

  In FIG. 2, reference numeral 1 denotes a cylindrical electrophotographic photosensitive member, which is driven to rotate at a predetermined peripheral speed in the direction of an arrow about an axis 2.

  The surface of the electrophotographic photosensitive member 1 that is rotationally driven is uniformly charged to a predetermined positive or negative potential by a charging unit (primary charging unit: charging roller or the like) 3, and then subjected to slit exposure, laser beam scanning exposure, or the like. Exposure light (image exposure light) 4 output from exposure means (not shown) is received. In this way, electrostatic latent images corresponding to the target image are sequentially formed on the surface of the electrophotographic photosensitive member 1.

  The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 1 is developed with toner contained in the developer of the developing means 5 to become a toner image. Next, the toner image formed and supported on the surface of the electrophotographic photoreceptor 1 is transferred from a transfer material supply means (not shown) to the electrophotographic photoreceptor 1 and the transfer means by a transfer bias from a transfer means (transfer roller or the like) 6. 6 (contact portion) is sequentially transferred onto a transfer material (paper or the like) P taken out and fed in synchronization with the rotation of the electrophotographic photosensitive member 1.

  The transfer material P that has received the transfer of the toner image is separated from the surface of the electrophotographic photosensitive member 1 and introduced into the fixing means 8 to receive the image fixing, and is printed out as an image formed product (print, copy). Is done.

  The surface of the electrophotographic photosensitive member 1 after the transfer of the toner image is cleaned by a cleaning means (cleaning blade or the like) 7 to remove the developer (toner) remaining after transfer, and further from a pre-exposure means (not shown). After being subjected to charge removal processing by pre-exposure light (not shown), it is repeatedly used for image formation. As shown in FIG. 2, when the charging unit 3 is a contact charging unit using a charging roller or the like, pre-exposure is not necessarily required.

  Among the above-described components such as the electrophotographic photosensitive member 1, the charging unit 3, the developing unit 5, the transfer unit 6 and the cleaning unit 7, a plurality of components are housed in a container and integrally combined as a process cartridge. The process cartridge may be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. In FIG. 2, the electrophotographic photosensitive member 1, the charging unit 3, the developing unit 5 and the cleaning unit 7 are integrally supported to form a cartridge, and the electrophotographic apparatus is used by using a guide unit 10 such as a rail of the electrophotographic apparatus main body. The process cartridge 9 is detachable from the main body.

  FIG. 3 shows an example of a schematic configuration of a color electrophotographic apparatus (in-line system) provided with a process cartridge having the electrophotographic photosensitive member of the present invention.

  In FIG. 3, reference numerals 1Y, 1M, 1C, and 1K denote cylindrical electrophotographic photosensitive members (first to fourth color electrophotographic photosensitive members), and the directions of the arrows are about axes 2Y, 2M, 2C, and 2K, respectively. Are rotated at a predetermined peripheral speed.

  The surface of the first color electrophotographic photoreceptor 1Y that is rotationally driven is uniformly charged to a predetermined positive or negative potential by a first color charging means (primary charging means: charging roller or the like) 3Y, and then slits Exposure light (image exposure light) 4Y output from exposure means (not shown) such as exposure and laser beam scanning exposure is received. The exposure light 4Y is exposure light corresponding to a first color component image (for example, a yellow component image) of a target color image. Thus, a first color component electrostatic latent image (yellow component electrostatic latent image) corresponding to the first color component image of the target color image is sequentially formed on the surface of the first color electrophotographic photoreceptor 1Y.

  The transfer material conveyance member (transfer material conveyance belt) 14 stretched by the tension roller 12 has substantially the same peripheral speed as the first to fourth color electrophotographic photoreceptors 1Y, 1M, 1C, 1K in the direction of the arrow ( For example, it is rotationally driven at 97 to 103% of the peripheral speeds of the first to fourth color electrophotographic photoreceptors 1Y, 1M, 1C, and 1K. Further, the transfer material (paper or the like) P fed from the transfer material supply means 17 is electrostatically carried (adsorbed) on the transfer material transport member 14, and the electrophotographic photoreceptor 1Y for the first to fourth colors. 1M, 1C, 1K and the transfer material conveyance member (contact portion) are sequentially conveyed.

  The first color component electrostatic latent image formed on the surface of the first color electrophotographic photoreceptor 1Y is developed with the toner of the first color developing means 5Y to become a first color toner image (yellow toner image). . Next, the first color toner image formed and supported on the surface of the first color electrophotographic photosensitive member 1Y is transferred to the first color electrophotographic image by the transfer bias from the first color transfer means (transfer roller or the like) 6Y. The image is sequentially transferred onto the transfer material P carried on the transfer material conveying member 14 that passes between the photoreceptor 1Y and the first color transfer means 6Y.

  The surface of the first color electrophotographic photosensitive member 1Y after the transfer of the first color toner image is cleaned by removing the transfer residual toner by the first color cleaning means (cleaning blade or the like) 7Y, and then repeatedly. Used for first color toner image formation.

  First color electrophotographic photoreceptor 1Y, first color charging means 3Y, first color exposure means for outputting exposure light 4Y corresponding to the first color component image, first color development means 5Y and first color The transfer unit 6Y is collectively referred to as a first color image forming unit.

  Second color electrophotographic photoreceptor 1M, second color charging means 3M, second color exposure means for outputting exposure light 4M corresponding to the second color component image, second color developing means 5M, and second color A second color image forming portion having a transfer means 6M, a third color electrophotographic photosensitive member 1C, a third color charging means 3C, and a third color output device that outputs exposure light 4C corresponding to the third color component image. Third color image forming unit having exposure means, third color developing means 5C and third color transfer means 6C, fourth color electrophotographic photoreceptor 1K, fourth color charging means 3K, fourth color component The operation of the fourth color image forming unit having the fourth color exposure unit that outputs the exposure light 4K corresponding to the image, the fourth color development unit 5K, and the fourth color transfer unit 6K is the first color image. It is the same as the operation of the forming unit, and is applied to the transfer material P that is carried on the transfer material conveying member 14 and to which the first color toner image is transferred. The second color toner image (magenta toner image), a third color toner image (cyan toner image), a fourth color toner image (black toner image) are sequentially transferred. In this way, a synthetic toner image corresponding to the target color image is formed on the transfer material P carried on the transfer material conveying member 14.

  The transfer material P on which the synthetic toner image is formed is separated from the surface of the transfer material conveying member 14, introduced into the fixing means 8, and subjected to image fixing to be printed out of the apparatus as a color image formed product (print, copy). Be out.

  Further, the first to fourth color electrophotographic photoconductors 1Y, 1M, 1C and 1K after the transfer residual toner is removed by the first to fourth color cleaning means 7Y, 7M, 7C and 7K As shown in FIG. 3, the first to fourth color charging units 3Y, 3M, 3C, and 3K are contact charging units using a charging roller or the like. In this case, pre-exposure is not always necessary.

  Among the above-described components such as the electrophotographic photosensitive member, charging unit, developing unit, transfer unit, and cleaning unit, a plurality of components are housed in a container and integrally combined as a process cartridge. Or an electrophotographic apparatus main body such as a laser beam printer. In FIG. 3, for each image forming unit, an electrophotographic photosensitive member, a charging unit, a developing unit, and a cleaning unit are integrally supported to form a cartridge, and a guide unit (not shown) such as a rail of an electrophotographic apparatus main body is provided. The process cartridges 9Y, 9M, 9C, and 9K are detachable from the main body of the electrophotographic apparatus.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to these. In the examples, “part” means “part by mass”. “Mw” means “weight average molecular weight”.

(Example 1-1)
An aluminum cylinder having a diameter of 30 mm and a length of 260.5 mm was used as a support.

Next, SnO ₂ coat-treated barium sulfate (conductive particles) 10 parts, titanium oxide (resistance pigment) 2 parts, phenol resin (binder resin) 6 parts, silicone oil (leveling agent) 0.001 part and methanol A conductive layer coating solution was prepared using a mixed solvent of 4 parts / 16 parts of methoxypropanol.

  This conductive layer coating solution was dip-coated on a support and cured (thermosetting) at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 15 μm.

  Next, an intermediate layer coating solution was prepared by dissolving 3 parts of N-methoxymethylated nylon and 3 parts of copolymer nylon in a mixed solvent of 65 parts of methanol / 30 parts of n-butanol.

  This intermediate layer coating solution was dip coated on the conductive layer and dried at 100 ° C. for 10 minutes to form an intermediate layer having a thickness of 0.7 μm.

  Next, strong peaks at 7.5 °, 9.9 °, 16.3 °, 18.6 °, 25.1 ° and 28.3 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction 10 parts of a crystalline form of hydroxygallium phthalocyanine (charge generating substance) having a hydrogen content of 250 parts of cyclohexanone and a solution of 5 parts of polyvinyl butyral resin (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.) Dispersion was performed in a 23 ± 3 ° C. atmosphere for 1 hour with a sand mill using glass beads having a diameter of 1 mm, and after dispersion, 250 parts of ethyl acetate was added to prepare a charge generation layer coating solution.

  This charge generation layer coating solution was dip-coated on the intermediate layer and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.26 μm.

  Next, the following formula (CTM-1)

And 8 parts of an amine compound (charge transport material) having a structure represented by formula (II) and an aliphatic dicarboxylic acid polyester resin having a repeating structural unit represented by the formula (1-2) (binder resin, homopolymer, Mw: A coating solution for charge transport layer was prepared by dissolving 10 parts of 150,000) in 80 parts of monochlorobenzene.

  The charge transport layer coating solution was dip coated on the charge generation layer and dried at 120 ° C. for 1 hour to form a charge transport layer having a thickness of 19 μm.

  In this manner, an electrophotographic photoreceptor having a charge transport layer as a surface layer was produced.

  Next, evaluation will be described. The evaluation was performed with respect to the light portion potential, the amount of change in the dark portion potential by the durability test, and the amount of surface abrasion.

  As an evaluation apparatus, a laser beam printer LBP-2510 manufactured by Canon Inc. (charging (primary charging): contact charging method, process speed: 94.2 mm / s), charging potential (dark part potential) of the electrophotographic photosensitive member is used. It was modified so that it could be adjusted.

  The evaluation was performed in an environment of 10 ° C. and 10% RH.

The exposure amount (image exposure amount) of the 780 nm laser light source of the evaluation apparatus was set so that the light amount on the surface of the electrophotographic photosensitive member was 0.3 μJ / cm ² .

  To measure the surface potential (dark part potential and bright part potential) of the electrophotographic photosensitive member, replace the jig and the developing device fixed so that the potential measuring probe is positioned 130 mm from the end of the electrophotographic photosensitive member. Then, it was carried out at the developing unit position.

  The dark part potential (VD) of the non-exposed part of the electrophotographic photosensitive member was set to −450 V, and the bright part potential (VL) that was light-attenuated from the dark part potential (VD) by irradiation with laser light was evaluated.

  In addition, 2000 A4 size plain paper was used for continuous image output, and the amount of change (ΔVD) in the dark portion potential (VD) before and after that was evaluated.

ΔVD = VD after outputting 2000 images−Initial VD
In addition, every time an image is output using A4 size plain paper, 5000 images are output in an intermittent mode in which the image is stopped once. After outputting 5000 images, the surface of the electrophotographic photosensitive member is initially printed. The amount of shaving was evaluated. The film thickness at that time was measured with a film thickness measuring device, Fisher MMS Eddy Current Method Probe EAW3.3, manufactured by Fischer Corporation.

  The results are shown in Table 4.

(Examples 1-2 to 1-47, Comparative Examples 1-1 to 1-25)
In Example 1-1, an electrophotographic photosensitive member in which the charge transport layer is a surface layer is produced in the same manner as in Example 1-1 except that the binder resin of the charge transport layer is as shown in Tables 1 to 3. And evaluated. The results are shown in Table 4.

  In Table 3, (C-1) to (C-13) are as follows.

(Example 2-1)
An aluminum plate was used as a support.

  Next, an intermediate layer coating solution was prepared by dissolving 3 parts of N-methoxymethylated nylon and 3 parts of copolymer nylon in a mixed solvent of 65 parts of methanol / 30 parts of n-butanol.

  This intermediate layer coating solution was applied onto a support with a Meyer bar and dried at 100 ° C. for 10 minutes to form an intermediate layer having a thickness of 0.7 μm.

  Next, the following formula (CGM-1)

20 parts of an azo pigment (charge generating material) having a structure represented by the following formula and 10 parts of butyral resin (degree of butyralization: 65 mol%) are added to 400 parts of tetrahydrofuran, and the atmosphere is 23 ± 3 ° C. in a sand mill using glass beads having a diameter of 1 mm The coating solution for charge generation layers was prepared by dispersing for 20 hours.

  The charge generation layer coating solution was applied onto the intermediate layer with a Meyer bar and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.4 μm.

  Next, the following formula (CTM-2)

And 8 parts of an amine compound (charge transport material) having a structure represented by formula (II) and an aliphatic dicarboxylic acid polyester resin having a repeating structural unit represented by the formula (1-2) (binder resin, homopolymer, Mw: A coating solution for charge transport layer was prepared by dissolving 10 parts of 150,000) in 80 parts of monochlorobenzene.

  This charge transport layer coating solution was applied onto the charge generation layer with a Meyer bar and dried at 120 ° C. for 1 hour to form a charge transport layer having a thickness of 24 μm.

  In this manner, an electrophotographic photoreceptor having a charge transport layer as a surface layer was produced.

  Next, evaluation will be described. Evaluation was performed on sensitivity and Taber abrasion.

  As the sensitivity evaluation apparatus, an electrostatic copying paper test apparatus EPA-8100 manufactured by Kawaguchi Electric Co., Ltd. was used.

The surface potential of the electrophotographic photosensitive member is charged to −600 V (dark portion potential) with a corona charger, and then light (exposure) is irradiated with light having wavelengths of 400 nm, 430 nm, and 450 nm with an LED, and the surface potential is − The amount of light required to attenuate to 300 V (bright part potential) was measured, and the half exposure sensitivity (E _1/2 ) was calculated at each wavelength.

The results are shown in Table 8. In Table 8, the sensitivity to light with a wavelength of 400 nm is E _{1/2 (400)} , the sensitivity to light with a wavelength of 430 nm is E _{1/2 (430),} and the sensitivity to light with a wavelength of 450 nm is E _{1/2 ( 450)} .

  Further, as a Taber abrasion amount evaluation apparatus, a rotary Taber abrasion tester manufactured by Yasuda Seiki Seisakusho Co., Ltd. was used. Two wear wheels CS-0 manufactured by Taber Instruments Co., Ltd. with a wrapping film C2000 manufactured by Fuji Film Co., Ltd. were used as wear wheels, and a load of 500 g was applied to each. The decrease in mass before and after rotational wear was measured and used as the Taber wear amount.

  The results are shown in Table 9.

(Examples 2-2 to 2-47, Comparative Examples 2-1 to 2-25)
An electrophotographic photosensitive member in which the charge transport layer is a surface layer is produced in the same manner as in Example 2-1, except that the binder resin for the charge transport layer is as shown in Tables 5 to 7 in Example 2-1. And evaluated. The results are shown in Tables 8 and 9.

  In Table 7, (C-1) to (C-13) are as described above.

It is a figure which shows the example of a layer structure of the electrophotographic photoreceptor of this invention. 1 is a diagram illustrating an example of a schematic configuration of an electrophotographic apparatus including a process cartridge having the electrophotographic photosensitive member of the present invention. 1 is a diagram illustrating an example of a schematic configuration of a color electrophotographic apparatus (in-line method) including a process cartridge having an electrophotographic photosensitive member of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Support body 104 Photosensitive layer 1041 Charge generation layer 1042 Charge transport layer 105 Protective layer 1 Electrophotographic photoreceptor 2 Axis 3 Charging means 4 Exposure light 5 Developing means 6 Transfer means 7 Cleaning means 8 Fixing means 9 Process cartridge 10 Guide means P Transfer Material 1Y Electrophotographic photosensitive member for first color 1M Electrophotographic photosensitive member for second color 1C Electrophotographic photosensitive member for third color 1K Electrophotographic photosensitive member for fourth color 2Y axis 2M axis 2C axis 2K axis 3Y For first color Charging means 3M Second color charging means 3C Third color charging means 3K Fourth color charging means 4Y Exposure light 4M Exposure light 4C Exposure light 4K Exposure light 5Y First color development means 5M Second color development means 5C Third color developing means 5K Fourth color developing means 6Y First color transferring means 6M Second color transferring means 6C Third color transferring means 6K Fourth color transferring means 7Y Cleaning means 9Y process cartridge 9M process cartridge 9C process cartridge 9K process cartridge 12 tension roller 14 the transfer material transport member cleaning unit 7K for the third color cleaning means 7C cleaning unit 7M second color for one color fourth color

Claims (11)

In an electrophotographic photosensitive member having a support and a photosensitive layer containing a charge generating material and a charge transporting material provided on the support, the surface layer of the electrophotographic photosensitive member is represented by the following formula (1). An electrophotographic photoreceptor comprising an aliphatic dicarboxylic acid polyester resin having a structural unit and a weight average molecular weight of 80,000 or more.

(In formula (1), R ^{11 to} R ¹⁸ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, or an aryl group. X ¹¹ is a carbon constituting the main chain, which is substituted or unsubstituted. An alkylene group having 3 to 10 atoms, a substituted or unsubstituted cycloalkylene group having 5 to 10 carbon atoms constituting the ring, or a substituted or unsubstituted ring containing 5 to 5 carbon atoms And Y ¹¹ represents a single bond, a group 16 element, or a divalent group having a structure represented by the following formula (2).

(In Formula (2), R ²¹ and R ²² each independently represent a hydrogen atom, an alkyl group, a fluorinated alkyl group, an alkoxy group, or an aryl group, or R ²¹ and R ²² are bonded to each other. A cycloalkylidene group or a fluorenylidene group formed by The electrophotographic photosensitive member according to claim 1, wherein at least one of R ^{11 to} R ¹⁸ in the formula (1) is an alkyl group, an alkoxy group, or an aryl group, and Y ¹¹ is a single bond. The electrophotographic photosensitive member according to claim 1, wherein Y ¹¹ in the formula (1) is an oxygen atom or a sulfur atom. At least one of R ^{11 to} R ¹⁸ in the formula (1) is an alkyl group, an alkoxy group or an aryl group, and Y ¹¹ is a divalent group having a structure represented by the formula (2); 2. The electrophotographic photoreceptor according to claim 1, wherein R ²¹ and R ²² in the formula (2) are each independently an alkyl group or a fluorinated alkyl group. At least one of R ^{11 to} R ¹⁸ in the formula (1) is an alkyl group, an alkoxy group or an aryl group, and Y ¹¹ is a divalent group having a structure represented by the formula (2); 2. The electrophotographic photosensitive member according to claim 1, wherein R ²¹ and R ²² in the formula (2) are cyclohexylidene groups formed by bonding R ²¹ and R ²² . X ¹¹ in the formula (1) is a substituted or unsubstituted butylene group, a substituted or unsubstituted pentylene group, a substituted or unsubstituted hexylene group, a substituted or unsubstituted heptylene group, a substituted or unsubstituted octylene group, or The electrophotographic photoreceptor according to claim 1, which is a substituted or unsubstituted cyclohexylene group.   The photosensitive layer is a laminated photosensitive layer having a charge generation layer containing the charge generation material and a charge transport layer containing the charge transport material, and the charge transport layer is a surface layer of the electrophotographic photoreceptor. Item 7. The electrophotographic photosensitive member according to any one of Items 1 to 6.   An electrophotographic apparatus main body integrally supporting the electrophotographic photosensitive member according to claim 1 and at least one means selected from the group consisting of a charging means, a developing means, a transfer means, and a cleaning means. A process cartridge that is detachable.   An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1, a charging unit, an exposure unit, a developing unit, and a transfer unit.   The electrophotographic apparatus according to claim 9, wherein the exposure unit is a unit for irradiating the electrophotographic photosensitive member with light having a wavelength of 380 to 450 nm as exposure light. The electrophotographic apparatus according to claim 10, wherein the exposure unit includes a laser having an oscillation wavelength in a range of 380 to 450 nm.

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