JP2005121926A - Electrophotographic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor free of defects in a conventional one and withstanding printing on a large number of sheets by diminishing abrasion loss and surface roughness of a photosensitive layer without degrading excellent electrophotographic properties. <P>SOLUTION: The electrophotographic photoreceptor contains a polycarbonate copolymer having a structure represented by the formula (1) as a binder resin in a photosensitive layer and contains at least one of compounds represented by the formula (2) as a charge transfer agent. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrophotographic photosensitive member used for contact charging (direct charging) in an electrophotographic apparatus such as a copying machine or a laser beam printer.

  In recent years, there has been a functionally separated organic photoconductor using a phthalocyanine or azo compound, which is known as an organic photoconductive material as an electrophotographic photoconductor, as a charge generation layer and a charge transfer layer made of a hydrazone compound or the like. It has become mainstream.

  As the binder resin used in this organic photoreceptor, bisphenol A type polycarbonate resin has been most commonly used. However, when a photosensitive layer is formed using a bisphenol A type polycarbonate resin as a binder resin, there are disadvantages such as the coating solution for the photosensitive layer being unstable.

  Since the photosensitive layer using this binder resin has a large coefficient of friction on the surface, when this electrophotographic photosensitive member is mounted on an electrophotographic apparatus and the electrophotographic process is repeated, the residual toner on the surface of the photosensitive layer is cleaned. There have been problems such as a commonly used cleaning blade reversing or generating abnormal noise.

  Furthermore, since this polycarbonate resin is poor in oil resistance, it may accidentally touch the surface of the photosensitive layer during the maintenance of the electrophotographic apparatus, resulting in fingerprints being attached. In many cases, cracks occur and the electrophotographic photosensitive member becomes unusable.

  On the other hand, in consideration of the stability of the coating solution, it has also been proposed to use a bisphenol Z-type polycarbonate resin as a material for the photosensitive layer of the electrophotographic photosensitive member. However, even when this bisphenol Z-type polycarbonate resin is used, the problem of the reversal of the blade, the generation of abnormal noise or cracks has not been solved.

Thereafter, a polycarbonate copolymer having a siloxane structure was developed, and a polycarbonate copolymer used in combination with a charge transfer agent was also proposed (for example, see Patent Document 1).
Japanese Unexamined Patent Publication No. 7-128874

  However, it has been found that the above problems cannot be solved completely.

  Furthermore, in the charging process in an electrophotographic apparatus, it has been common to apply a charge to the surface of the photoreceptor by corona charging. However, a charging member called contact charging, which generates less ozone than corona charging, is directly applied to the photoreceptor. A method of applying a charge by abutting has become mainstream. Although this method has an ozone suppression effect, since the charging member and the photoconductor are in direct contact with each other, the surface of the photoconductor surface layer is relatively large, or the charging potential is lowered due to the reduction in film thickness. Measures are desired. In addition, with the increase in process speed, the reduction of the photosensitive layer due to process running is also a problem. When the amount of film reduction increases, the density of the printed image decreases or positive memory or the like occurs.

  In addition, toner filming or the like, which is considered to be caused by the surface roughness of the photosensitive layer, often occurs.

  An object of the present invention is to reduce the amount of wear and surface roughness of the photosensitive layer of an electrophotographic photosensitive member used in a contact charging device, thereby eliminating the disadvantages of conventional ones and capable of withstanding a large number of prints. A photographic photoreceptor and an electrophotographic apparatus are provided.

  As a result of intensive studies to solve the above problems, the present inventors have found that an electrophotographic photosensitive film containing a polycarbonate copolymer having a specific structure as a binder resin in a photosensitive layer and using a charge transfer agent having a specific structure. The present inventors have found that the body and the electrophotographic apparatus using the same are free from the problems of the prior art and maintain excellent electrostatic characteristics over a long period of time, and have completed the present invention.

  That is, according to a photoreceptor using a specific polycarbonate copolymer resin having a terminal structural group containing a fluorine atom represented by the general formula [I] to be described later, the coefficient of friction on the surface of the photoreceptor due to continuous printing as compared with the prior art It was found that an electrophotographic photosensitive member that can withstand a large number of prints can be provided. Further, the molecular weight of the main chain polycarbonate copolymer resin is preferably in the range of 1,000 to 100,000, and if it exceeds 100,000, the viscosity becomes too high and the film formability is difficult. In addition, it was found that a photoconductor capable of improving compatibility and wear resistance and providing excellent electrophotographic characteristics can be obtained by combination with the charge transfer agent of the general formula [II] or the general formula [III] described later. .

  The invention according to claim 1 made based on such a viewpoint is used in an electrophotographic apparatus having means for applying a voltage to an electrophotographic photosensitive member by contact charging, and at least a charge generating agent and a charge transfer on a conductive support. An electrophotographic photoreceptor having a photosensitive layer having an agent and a binder resin, comprising a polycarbonate copolymer having a structure represented by the general formula [I] as a binder resin in the photosensitive layer, and a charge transfer agent As an electrophotographic photoreceptor, it contains at least one compound represented by general formula [II] or general formula [III].

Formula [I]

[Wherein R ₃₁ represents a halogen atom, an alkylene group, an arylene group having 6 to 12 carbon atoms or a substituted arylene group, R ₃₂ represents a hydrogen atom or a fluorinated alkyl group, and e represents 1 Represents an integer of ~ 20. ]

Formula [II]

[Wherein, R ₂₁ and R ₂₂ each independently represent a C 1-6 alkyl group which may have a substituent, and R ₂₃ represents either a hydrogen atom or a dialkylamino group. ]

General formula [III]

[Wherein R _{24 to} R ₂₇ may be the same or different and each independently has a hydrogen atom, a halogen atom, an alkyl or alkoxy group having 1 to 6 carbon atoms, or a substituent. R ₂₈ represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms or an alkoxy group, an aryl group which may have a substituent, or a substituent. It represents either an alkenyl group or an alkadienyl group, or general formula (III ′), and f represents an integer of 0 or 1. ]
Formula [III ']

(In the formula, R ₂₉ and R ₃₀ may be the same or different, and each independently has a hydrogen atom, a halogen atom, an alkyl or alkoxy group having 1 to 6 carbon atoms, or a substituent. Any of the aryl groups that may be present, and n represents an integer of 0 or 1.)

  According to the first aspect of the present invention having such a configuration, the releasability and lubricity are improved, so that the friction coefficient of the photosensitive layer is reduced.

  Further, by containing the compound represented by the general formula [II] or the general formula [III] as a charge transfer agent, it is possible to provide a photoconductor having little compatibility and environment dependency.

  The invention according to claim 2 is an electrophotographic photoreceptor comprising a polycarbonate copolymer containing a repeating unit represented by the general formula [IV].

Formula [IV]


[Wherein, R _{1 to} R ₁₂ each independently represents an alkyl group having 1 to 6 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, and a to c represent an integer of 2 to 6; D represents an integer of 0 to 200. ]

  According to the invention described in claim 3 having such a configuration, the combination with the specific structural group of the general formula [I] can further improve the releasability and lubricity and reduce the friction coefficient of the photosensitive layer.

  The invention according to claim 3 is an electrophotographic photoreceptor comprising a polycarbonate copolymer containing a repeating unit represented by the general formula [V].

General formula [V]

[Wherein, R _{33 to} R ₃₆ each independently represent a halogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a substituted aryl group, and g, h and i are , Each independently represents an integer of 0-4. ]

  According to the invention of claim 3 having such a configuration, the combination with the specific structural group of the general formula [I] has an effect of improving the compatibility with the charge transfer agent and the film forming property.

  The invention according to claim 4 is an electrophotographic photoreceptor comprising a polycarbonate copolymer containing a repeating unit represented by the general formula [VI].

Formula [VI]


(In the formula, R ₃₇ and R ₃₈ each independently represent a halogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a substituted aryl group; Represents an integer of 0 to 4. j and k represent the number of saturated hydrocarbon straight chain, and are integers of 1 to 20.)

  According to the invention described in claim 5 having such a configuration, the combination with the specific structural group of the general formula [I] has an effect of improving the compatibility with the charge transfer agent and the film forming property.

  The invention according to claim 5 is an electrophotographic photoreceptor comprising a polycarbonate copolymer containing a repeating unit represented by the general formula [VII].

General formula [VII]

[Wherein, R _{39 to} R ₄₂ each independently represent a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclohexyl group, an aryl group having 6 to 12 carbon atoms, or a substituted aryl group; It represents any of a bond, —O—, —CO—, —S—, —SO—, —SO ₂ —, and p, q, r and s are integers of 0 to 4. ]

  According to the invention of claim 6 having such a configuration, the combination with the specific structural group of the general formula [I] has an effect of improving the compatibility with the charge transfer agent and the film forming property.

  According to a sixth aspect of the present invention, there is provided an electrophotographic apparatus comprising the electrophotographic photosensitive member according to any one of the first to fifth aspects.

  According to the invention described in claim 6 having such a configuration, when mounted on an electrophotographic apparatus having contact charging that requires wear resistance and potential stability more than conventional corona charging, it is excellent when used repeatedly. An electrophotographic apparatus having durability, potential characteristics, and image characteristics is provided.

  Hereinafter, specific examples of the general formula [I], the general formula [IV], the general formula [V], the general formula [VI], and the general formula [VII] as the binder resin used in the photosensitive layer of the present invention are as follows. Although shown, it is not limited to these.

Specific examples of the general formula [IV] are shown below.
Formula [IVa]

Specific examples of the general formula [V] are shown below.
Formula [Va]

Formula [Vb]

Formula [Vc]

Formula [Vd]

Specific examples of the general formula [VI] are shown below.
Formula [Ve]

Formula [VIa]

Formula [VIb]

Specific examples of the general formula [VII] are shown below.
Formula [VIIa]

  Specific examples of the general formula [II] and general formula [III] are shown below as the charge transfer agent used in the photosensitive layer of the present invention, but are not limited thereto.

Formula [IIa]

Formula [IIb]

Formula [IIc]

Formula [IIIa]

Formula [IIIb]

Formula [IIIc]

Formula [IIId]

Formula [IIIe]

The electrophotographic photosensitive member of the present invention is not affected by electrostatic characteristics such as surface potential and sensitivity, and the amount of film loss after printing is very small and the surface roughness is small. No filming occurs.
Therefore, according to the present invention, an electrophotographic photosensitive member having excellent electrophotographic characteristics and having a long life can be provided.

Hereinafter, preferred embodiments of the electrophotographic photosensitive member according to the present invention will be described in detail.
The present invention provides, for example, a functionally separated electron in which a charge generation layer containing at least a charge generation agent is formed on a conductive support, and a charge transfer layer containing at least a charge transfer agent is formed thereon. It is applied to a photographic photoreceptor. In this case, a photosensitive layer is formed by the charge generation layer and the charge transfer layer.
The present invention also relates to a single-layer type electrophotographic photosensitive member in which a charge generating agent and a charge transfer agent are contained in the same layer, a reverse stacked type electrophotographic photosensitive member in which a charge transfer layer and a charge generating layer are laminated in this order, etc. It can also be applied to.

  Examples of the conductive support that can be used in the present invention include aluminum, brass, stainless steel, nickel, chromium, titanium, gold, silver, copper, tin, platinum, molybdenum, indium, and the like, or a processed body of an alloy thereof. And conductive plates such as metal and carbon treated by vapor deposition, plating, etc. to give conductivity, plastic plates and films, and conductive glass coated with tin oxide, indium oxide, aluminum iodide, etc. The conductive support can be formed using various materials having conductivity without being limited by the type or shape. Moreover, about the shape of an electroconductive support body, the thing of drum shape, rod shape, plate shape, sheet shape, and belt shape can be used.

  In general, a cylindrical aluminum tube alone, a surface thereof anodized, or an aluminum tube or an alumite layer formed with a resin layer are often used. This resin layer has a function of improving adhesion, a barrier function for preventing an inflow current from the support, and a function for covering defects on the support surface. Various resins such as polyethylene resin, acrylic resin, epoxy resin, polycarbonate resin, polyurethane resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, polyamide resin, and nylon resin can be used for this resin layer. These resin layers may be composed of a single resin, or may be composed of a mixture of two or more resins or a combination with alumite treatment. In addition, a metal compound, metal oxide, carbon, silica, resin powder and the like can be dispersed in the layer. Furthermore, various pigments, electron accepting substances, electron donating substances, and the like can be contained for improving the characteristics.

  As the charge generating agent that can be used in the present invention, a disazo pigment or oxytitanium phthalocyanine is desirable in terms of good sensitivity compatibility, but is not limited thereto. Others such as selenium, selenium-tellurium, selenium-arsenic, amorphous silicon, metal-free phthalocyanine, other metal phthalocyanine pigments, monoazo pigments, trisazo pigments, polyazo pigments, indigo pigments, selenium pigments, toluidine pigments, pyrazoline pigments, perylene pigments Quinacridone pigments, polycyclic quinone pigments, pyrylium salts, and the like can be used.

  These charge generating agents may be used alone or in combination of two or more in order to obtain an appropriate photosensitivity wavelength and sensitizing action.

The polycarbonate copolymer was formed such that a reduced viscosity (η _sp / c) at 20 ° C. of a solution having a concentration of 0.5 g / dl using methylene chloride as a solvent was 0.70 dl / g or more. It is preferable because the hardness of the photosensitive layer increases.

  In addition, when the photosensitive layer has a laminated type or a reverse laminated type, the binder resin of the present invention may be used for one or both of the charge generation layer and the charge transfer layer. In view of the characteristics, when it is contained in the outermost surface layer, desired characteristics are sufficiently exhibited, which is preferable.

  On the other hand, in the electrophotographic photoreceptor of the present invention, a binder resin other than the specific polycarbonate copolymer described above can be contained in the photosensitive layer.

  As the binder resin that can be used to form the photosensitive layer, a thermoplastic resin, a thermosetting resin, a photocurable resin, or the like can be used. These resins include polycarbonate resin, styrene resin, acrylic resin, styrene-acrylic resin, ethylene-vinyl acetate resin, polypropylene resin, vinyl chloride resin, chlorinated polyether, vinyl chloride-vinyl acetate resin, polyester resin, furan resin. , Nitrile resin, alkyd resin, polyacetal resin, polymethylpentene resin, polyamide resin, polyurethane resin, epoxy resin, polyarylate resin, diarylate resin, polysulfone resin, polyethersulfone resin, polyallylsulfone resin, silicone resin, ketone resin, Polyvinyl butyral resin, polyether resin, phenol resin, EVA (ethylene / vinyl acetate / copolymer) resin, ACS (acrylonitrile / chlorinated polyethylene / styrene) resin, ABS Acrylonitrile-butadiene-styrene) resins, epoxy polyarylate. These may be used alone or in combination of two or more. In addition, it is more preferable to use a mixture of resins having different molecular weights because the hardness and wear resistance can be improved.

  The electrophotographic photoreceptor of the present invention contains at least one compound represented by the general formula [II] or the general formula [III] as a charge transfer agent in the photosensitive layer.

  In this case, the content of the compound represented by the general formula [II] or the general formula [III] in the charge transfer layer is 0.3 to 2.0 parts by weight with respect to 1 part by weight of the binder resin. Is more preferable, and 0.5 to 1.2 parts by weight is more preferable.

  If the content of this compound is less than 0.3 parts by weight, the electrical characteristics deteriorate, for example, the residual potential increases. On the other hand, when the amount is more than 2.0 parts by weight, mechanical properties such as wear resistance are deteriorated.

  Among the compounds represented by the general formula [II], a compound represented by the formula [IIb] or a compound represented by the formula [IIIa] is particularly preferable.

  Of the compounds represented by the general formula [II] or the general formula [III], those having an IP value of 4.95 to 5.25 eV are particularly preferable.

  Furthermore, other charge transfer agents can be added to the photosensitive layer of the electrophotographic photoreceptor of the present invention. In that case, since the sensitivity of the photosensitive layer can be increased and the residual potential can be lowered, the characteristics of the electrophotographic photosensitive member of the present invention can be improved.

  Examples of charge transfer agents that can be added to improve such properties include polyvinyl carbazole, halogenated polyvinyl carbazole, polyvinyl pyrene, polyvinyl indoloquinoxaline, polyvinyl benzothiophene, polyvinyl anthracene, polyvinyl acridine, polyvinyl pyrazoline, polyacetylene, polythiophene, Conductive polymer compounds such as polypyrrole, polyphenylene, polyphenylene vinylene, polyisothianaphthene, polyaniline, polydiacetylene, polyheptadiene, polypyridinediyl, polyquinoline, polyphenylene sulfide, polyferrocenylene, polyperinaphthylene, polyphthalocyanine, etc. Can be used.

  In addition, as low molecular weight compounds, trinitrofluorenone, tetracyanoethylene, tetracyanoquinodimethane, quinone, diphenoquinone, naphthoquinone, anthraquinone and derivatives thereof, polycyclic aromatic compounds such as anthracene, pyrene, phenanthrene, indole, carbazole Nitrogen-containing heterocyclic compounds such as imidazole, fluorenone, fluorene, oxadiazole, oxazole, pyrazoline, triphenylmethane, enamine, stilbene, butadiene, hydrazone, triphenylamine compounds other than the above should be added as charge transfer agents Can do.

  Also, as a charge transfer agent for the same purpose, a polymer solid electrolyte doped with a metal ion such as Li (lithium) ion to a polymer compound such as polyethylene oxide, polypropylene oxide, polyacrylonitrile, polymethacrylic acid or the like is added. You can also.

  Further, as a charge transfer agent for the same purpose, an organic charge transfer complex formed of an electron donating substance typified by tetrathiafulvalene-tetracyanoquinodimethane and an electron accepting substance can be used.

  The charge transfer agent can obtain desired photoreceptor characteristics even when it is added alone or in a mixture of two or more compounds.

  The electrophotographic photosensitive member of the present invention contains an antioxidant or an ultraviolet absorber in the photosensitive layer for the purpose of property change due to oxidative degradation of the photoconductive material or binder resin, prevention of cracks, and improvement of mechanical strength. It is preferable to do.

  Examples of antioxidants that can be used in the present invention include 2,6-di-tert-butylphenol, 2,6-di-tert-4-methoxyphenol, 2-tert-butyl-4-methoxyphenol, 2,4. -Dimethyl-6-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, butylated hydroxyanisole, stearyl propionate-β- (3,5-di-tert-butyl-4-hydroxyphenyl ), Α-tocopherol, β-tocopherol, monophenols such as n-octadecyl-3- (3′-5′-di-tert-butyl-4′-hydroxyphenyl) propionate, 2,2′-methylenebis (6 -Tert-butyl-4-methylphenol), 4,4'-butylidene-bis- (3-methyl-) -Tert-butylphenol), 4,4'-thiobis (6-tert-butyl-3-methylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis [methylene-3 (3,5-di-tert-butyl-4 -Hydroxyphenyl) propionate] Polyphenols such as methane are preferred, and one or more of them can be simultaneously contained in the photosensitive layer.

  Moreover, as an ultraviolet absorber, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole 2- (3,5-di-tert-butyl-2-hydroxyphenyl) benzotriazole, 2- (3-tert-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- ( 3,5-di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-tert-amyl-2-hydroxyphenyl) benzotriazole, 2- (2′-hydroxy -5'-tert-octylphenyl) benzotriazoles such as benzotriazole, phenyl salicylate, salicyl A salicylic acid type such as acid-p-tert-butylphenyl and salicylic acid-p-octylphenyl is preferred, and one or more of these can be simultaneously contained in the photosensitive layer.

  Further, the antioxidant and the ultraviolet absorber can be added simultaneously. These layers may be added to any layer in the photosensitive layer, but are preferably added to the outermost layer, particularly the charge transfer layer.

  The addition amount of the antioxidant is preferably 3 to 20% by weight with respect to the binder resin, and the addition amount of the ultraviolet absorber is preferably 3 to 30% by weight with respect to the binder resin. preferable. Furthermore, when adding both an antioxidant and an ultraviolet absorber, it is preferable that the addition amount of both components shall be 5 to 40 weight% with respect to binder resin.

  In addition to the antioxidant and the ultraviolet absorber, a light stabilizer such as a hindered amine or a hindered phenol compound, an anti-aging agent such as a diphenylamine compound, a surfactant, or the like may be added to the photosensitive layer.

  As a method for forming the photosensitive layer, a method in which a coating solution is prepared by dispersing or dissolving in a solvent together with a predetermined photosensitive material and a binder resin, and coating is performed on a predetermined surface.

As a coating method, dip coating, curtain flow, bar coating, roll coating, ring coating, spin coating, spray coating, and the like can be performed according to the shape of the base and the state of the coating liquid.
The charge generation layer can also be formed by a vacuum deposition method.

  Solvents used in the coating solution include alcohols such as methanol, ethanol, n-propanol, i-propanol, and butanol, saturated aliphatic hydrocarbons such as pentane, hexane, heptane, octane, cyclohexane, cycloheptane, toluene, Aromatic hydrocarbons such as xylene, chlorinated hydrocarbons such as dichloromethane, dichloroethane, chloroform, chlorobenzene, ethers such as dimethyl ether, diethyl ether, tetrahydrofuran (THF), methoxyethanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc. Esters such as ketones, ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, N, N-dimethylformamide, dimethylsulfoxide There is a de like. These may be used alone or as a mixture of two or more solvents.

  In addition, a thin film composed of an organic thin film such as polyvinyl formal resin, polycarbonate resin, fluororesin, polyurethane resin, or silicon resin, or a siloxane structure formed from a hydrolyzate of a silane coupling agent is formed on the surface of the photosensitive layer. A surface protective layer may be provided as a film. In that case, the durability of the photoreceptor is improved, which is preferable. This surface protective layer may be provided in order to improve functions other than the durability improvement.

  Hereinafter, examples of the electrophotographic photosensitive member according to the present invention will be described in detail together with comparative examples.

Example 1
On a cylindrical drum made of aluminum having a diameter of 30 mm, a dispersion of α-type oxytitanium phthalocyanine using polyvinyl butyral as a binder resin was applied by dip coating to form a charge generation layer.

  Next, a polycarbonate copolymer combined with Formula [Ic], Formula [IVa], Formula [Vb] and Formula [VIIa] as a binder resin, and a compound represented by Formula [IIb] as a charge transfer agent, 2,6-Di-tert-butyl-4-methylphenol as an antioxidant to chloroform in a weight ratio of polycarbonate copolymer / charge transfer agent / antioxidant = 1.0 / 0.8 / 0.1 It melt | dissolved and the coating liquid was prepared.

  And after apply | coating this coating liquid by dip coating, it dried at the temperature of 100 degreeC for 1 hour, and formed the charge transfer layer with a film thickness of 24 micrometers. An electrophotographic photosensitive member was produced by the method described above.

Example 2
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the polycarbonate copolymer of Example 1 was changed to Formula [Ia] instead of Formula [Ic].

Example 3
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the polycarbonate copolymer of Example 1 was changed to Formula [VIa] instead of Formula [Vb].

Example 4
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the compound represented by the formula [IIIa] was used instead of the charge transfer agent represented by the formula [IIb] in Example 1.

Comparative Example 1
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that instead of the polycarbonate copolymer of Example 1, the one excluding the formula [Ic] was used.

Comparative Example 2
In place of the polycarbonate copolymer of Example 1, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that only the polycarbonate resin of the formula [VIa] was used.

Comparative Example 3
In place of the polycarbonate copolymer of Example 1, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that only the polycarbonate resin of the formula [Vc] was used.

Comparative Example 4
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that a hydrazone compound represented by the following formula [VIII] was used instead of the charge transfer agent represented by the formula [IIb] in Example 1. did.

Formula [VIII]

Evaluation method (measurement of electrostatic characteristics)
Using an electrophotographic photosensitive member evaluation apparatus (manufactured by Yamanashi Denshi Kogyo Co., Ltd.), the electrostatic characteristics such as initial surface potential, sensitivity, residual potential, dark decay rate, etc. of the electrophotographic photosensitive member produced by Examples and Comparative Examples are measured. However, all had good characteristics.

(Image evaluation)
The following printing tests were performed on the electrophotographic photoreceptors produced in the examples and comparative examples.
The electrophotographic photosensitive member is negatively charged by a roller charging method (contact charging method), and mounted on an electrophotographic apparatus for forming an image by LED exposure, a non-magnetic one-component developing method, and a blade cleaning method, and 30,000 A4 sheets are loaded. Sheets were intermittently printed, and the image after printing was evaluated. The results are shown in Table 2.

  The presence or absence of positive memory was visually evaluated for the first printed image and the printed image after printing a predetermined number of images. Further, after printing a predetermined number of sheets, it was visually checked whether toner filming occurred on the surface of the electrophotographic photosensitive member. The results are shown in Table 2.

[Measurement of surface roughness]
Ten-point average roughness Rz of the surface of the electrophotographic photosensitive member produced in Examples and Comparative Examples was measured using a contact type surface roughness meter. The measurement was performed before and after printing the image evaluation. The results are shown in Table 2. The ten-point average roughness Rz before printing was about 0.1 μm in both the examples and the comparative examples.

(Measurement of film loss)
About the photosensitive layer of the electrophotographic photosensitive member produced in the Example and the comparative example, the film thickness was measured using the non-contact-type film thickness meter. The measurement was performed before and after printing the image evaluation. The film reduction amount Δd after printing is a value obtained by subtracting the film thickness d ₁ after printing from the film thickness d ₀ before printing. The results are shown in Table 2.

  As is apparent from Table 2, Examples 1 to 4 in image evaluation have little decrease in film thickness after printing a predetermined number of sheets and do not adversely affect electrical characteristics. Further, the density was not reduced, positive memory and toner filming did not occur, and the printed image was good.

Claims (6)

An electrophotographic apparatus which is used in an electrophotographic apparatus having means for applying a voltage to an electrophotographic photosensitive member by contact charging, and in which a photosensitive layer having at least a charge generating agent, a charge transfer agent and a binder resin is formed on a conductive support. The photoreceptor contains a polycarbonate copolymer having a structure represented by the general formula [I] as a binder resin in the photosensitive layer, and is represented by the general formula [II] or the general formula [III] as a charge transfer agent. An electrophotographic photoreceptor comprising at least one of the following compounds.
Formula [I]

[Wherein R ₃₁ represents an alkylene group, an arylene group having 6 to 12 carbon atoms, or a substituted arylene group, R ₃₂ represents a hydrogen atom or a fluorinated alkyl group, and e represents 1 to 20 Represents an integer. ]
Formula [II]

[Wherein, R ₂₁ and R ₂₂ each independently represent a C 1-6 alkyl group which may have a substituent, and R ₂₃ represents either a hydrogen atom or a dialkylamino group. ]
General formula [III]

[Wherein R _{24 to} R ₂₇ may be the same or different and each independently has a hydrogen atom, a halogen atom, an alkyl or alkoxy group having 1 to 6 carbon atoms, or a substituent. R ₂₈ represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms or an alkoxy group, an aryl group which may have a substituent, or a substituent. It represents either an alkenyl group or an alkadienyl group, or general formula (III ′), and f represents an integer of 0 or 1. ]
Formula [III ']


(In the formula, R ₂₉ and R ₃₀ may be the same or different, and each independently has a hydrogen atom, a halogen atom, an alkyl or alkoxy group having 1 to 6 carbon atoms, or a substituent. Any of the aryl groups that may be present, and n represents an integer of 0 or 1.) The electrophotographic photoreceptor according to claim 1, comprising a polycarbonate copolymer containing a repeating unit represented by the general formula [IV].
Formula [IV]

[Wherein, R _{1 to} R ₁₂ each independently represents an alkyl group having 1 to 6 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, and a to c represent an integer of 2 to 6; D represents an integer of 0 to 200. ] The electrophotographic photoreceptor according to claim 1, comprising a polycarbonate copolymer containing a repeating unit represented by the general formula [V].
General formula [V]

[Wherein, R _{33 to} R ₃₆ each independently represent a halogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a substituted aryl group, and g, h and i are , Each independently represents an integer of 0-4. ] 2. The electrophotographic photoreceptor according to claim 1, comprising a polycarbonate copolymer containing a repeating unit represented by the general formula [VI].
Formula [VI]

(In the formula, R ₃₇ and R ₃₈ each independently represent a halogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a substituted aryl group; Represents an integer of 0 to 4. j and k represent the number of saturated hydrocarbon straight chain, and are integers of 1 to 20.) The electrophotographic photosensitive member according to claim 1, comprising a polycarbonate copolymer containing a repeating unit represented by the general formula [VII].
General formula [VII]

[Wherein, R _{39 to} R ₄₂ each independently represent a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclohexyl group, an aryl group having 6 to 12 carbon atoms, or a substituted aryl group; It represents any of a bond, —O—, —CO—, —S—, —SO—, —SO ₂ —, and p, q, r and s are integers of 0 to 4. ]   An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1.