JP2012098500A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor that has favorable abrasion resistance and favorable cleaning property and does not generate image blurring and exhibits excellent durability.SOLUTION: In an electrophotographic photoreceptor obtained by successively laminating at least a photosensitive layer and a protective layer on a conductive support, the protective layer contains a polymerization product between a fluorine-containing compound represented by general formula (1) and a polymerizable compound having 7 or more and 10 or less of polymerizable functional groups and 140 or less of polymerizable functional group equivalent in a molecule. In the formula, R represents a hydrogen atom or a methyl group; A represents a hydrogen atom or a fluorine atom; n represents 1 or 2; and m represents an integer of 0 to 5.

Description

  The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor used in an electrophotographic image forming apparatus.

  In recent years, organic photoreceptors containing organic photoconductive materials have been widely used as electrophotographic photoreceptors. Organic photoconductors are advantageous for inorganic photoconductors because it is easy to develop materials compatible with various exposure light sources from visible light to infrared light, the ability to select materials without environmental pollution, and low manufacturing costs. Is a point.

  On the other hand, electrophotographic photoreceptors (hereinafter also referred to as photoreceptors) are easily deteriorated because they are directly subjected to electrical or mechanical external forces due to charging, exposure, development, transfer, cleaning, etc., and image formation is repeatedly performed. However, there is a demand for durability that can be stably maintained, such as charging stability and potential retention.

  In recent years, especially in the digital trend, demand for high-definition and high-quality images has increased, and toners with small particle diameters by polymerization methods such as dissolved suspension toners and emulsion polymerization aggregation toners have become mainstream. The toner having a small particle size has a large adhesion force to the surface of the photoconductor, and the removal of residual toner such as transfer residual toner adhering to the surface of the photoconductor tends to be insufficient. In the cleaning method using a rubber blade (hereinafter also referred to as blade cleaning), “toner slipping” in which the toner passes through the blade, “blade curling” in which the blade is reversed, or generation of a rubbing sound between the photosensitive member and the blade, so-called “ The phenomenon of “blading” is likely to occur. In order to solve the “toner slipping”, it is necessary to increase the contact pressure of the blade to the photosensitive member. However, the repeated use causes the problem that the surface of the organic photosensitive member is worn and the durability is insufficient. appear. Further, it is required to have sufficient durability against deterioration caused by ozone and nitrogen oxides generated during charging.

  For these reasons, a technique for improving the mechanical strength by providing a protective layer (also referred to as a surface layer) on the surface of the photoreceptor has been proposed.

  Specifically, a polymerizable compound generally called a curable compound is used for the photoconductor protective layer, and after the coating, a curing reaction is performed, thereby being resistant to surface abrasion and scratches caused by friction of a cleaning blade or the like. Techniques have been proposed for producing a photosensitive member having a certain property (see, for example, Patent Document 1 and Patent Document 2).

  Moreover, in order to improve the abrasion resistance of a protective layer, the technique using the monomer which has three or more radically polymerizable groups in 1 molecule is disclosed (for example, refer patent document 3).

  Further, a technique has been proposed in which inorganic fine particles such as silica are dispersed in a protective layer to improve mechanical strength (see, for example, Patent Document 4).

  On the other hand, a technique for reducing the surface energy of the surface of an electrophotographic photosensitive member has been proposed in order to impart a toner adhesion preventing function to the electrophotographic photosensitive member and excellent cleaning and transferability. As a technique for reducing the surface energy, a technique for adding a lubricant to the outermost protective layer of the electrophotographic photosensitive member has been proposed, and a technique for adding various fluororesins and silicone compounds as the lubricant is disclosed ( For example, see Patent Documents 5, 6, 7, 8, and 9).

JP 11-288121 A JP 2009-69241 A JP 2009-251140 A JP 2002-333733 A JP-A-63-73267 JP-A-5-323646 JP-A-11-344818 JP 2005-115353 A JP-A-6-308756

  In order to improve the wear resistance and scratch resistance of the surface of an electrophotographic photosensitive member (hereinafter also referred to as a photosensitive member) and increase durability, it is preferable to increase the hardness of the protective layer. As a means for increasing the hardness of the protective layer and achieving further high durability, it is conceivable to increase the crosslinking density of the protective layer, and as a means for increasing the crosslinking density and increasing the hardness of the protective layer, It is considered effective to select a polyfunctional polymerizable compound having a large number of polymerizable functional groups.

  On the other hand, as a means for improving the wear resistance, by introducing a fluorine compound into the photosensitive member protective layer, the surface energy of the photosensitive member surface is lowered and the cleaning property is improved, so that residual toner, discharge oxide, etc. Attempts have been made to prevent image defects due to deposits. However, even if the polymerizable compound is cured in the presence of the fluorine compound, there has been a problem that the phase separation between the fluorine compound and the cured product of the polymerizable compound is caused and the strength of the protective layer is lowered. In addition, attempts have been made to suppress a decrease in strength by incorporating a fluorine compound having a polymerizable functional group into a curing system in combination with a polymerizable monomer. However, the molecular weight of the fluorine compound itself is large, and the polymerizability per molecule is high. When the number of functional groups is small, the crosslinking density is lowered, a protective layer having a high film hardness cannot be obtained, and it is difficult to obtain a protective layer having sufficient film strength.

  The present invention has been made to solve the above-described problems, and provides an electrophotographic photosensitive member that has excellent wear resistance, good cleaning properties, no image blur, and excellent durability. It is aimed.

The above-described problems of the present invention are solved by the following configuration.
1.
In an electrophotographic photosensitive member formed by sequentially laminating at least a photosensitive layer and a protective layer on a conductive support, the protective layer contains a fluorine-containing compound represented by the following general formula (1) and the number of polymerizable functional groups in one molecule. 7 to 10 and contains a polymerization product with a polymerizable compound having a polymerizable functional group equivalent of 140 or less.

(In the formula, R represents a hydrogen atom or a methyl group, A represents a hydrogen atom or a fluorine atom, n represents 1 or 2, and m represents an integer of 0 to 5)
2.
2. The electrophotographic photoreceptor according to 1 above, wherein the polymerizable compound is a polymerizable monomer or polymerizable oligomer having an acryloyl group or a methacryloyl group as a polymerizable functional group.
3.
3. The electrophotographic photosensitive member according to 1 or 2 above, wherein the protective layer contains metal oxide fine particles.
4).
The metal oxide fine particles are surface-treated with a compound having either an acryloyl group or a methacryloyl group, and the metal oxide fine particles are selected from alumina fine particles, tin oxide fine particles, or titanium oxide fine particles. 4. The electrophotographic photosensitive member as described in 3 above, which is one type.

  By adopting the above-described configuration, the present invention can provide a photoconductor with excellent wear resistance and high image quality and high durability with no image blur even in a high humidity environment.

FIG. 3 is a schematic diagram illustrating an example of a layer configuration of a photoreceptor according to the present invention. 1 is a schematic cross-sectional view illustrating an example of an image forming apparatus using a photoreceptor according to the present invention.

  Hereinafter, embodiments for carrying out the present invention will be described in detail, but the present invention is not limited thereto.

  The present invention relates to an electrophotographic photosensitive member in which at least a photosensitive layer and a protective layer are sequentially laminated on a conductive support, and the protective layer contains a fluorine-containing compound represented by the following general formula (1) and one molecule. A polymerization product of a polymerizable compound (hereinafter also referred to as a polymerizable compound of the present invention) having a polymerizable functional group number of 7 to 10 and a polymerizable functional group equivalent of 140 or less. It is a feature. That is, the photosensitive member protective layer is cured by combining a fluorine compound having a polymerizable functional group and a polymerizable compound having a polymerizable functional group number of 7 to 10 and a polymerizable functional group equivalent of 140 or less in one molecule. In addition, the surface energy of the protective layer is lowered and the releasability is improved by adding a fluorine-containing compound, thereby improving the cleaning property and suppressing the image blur.

(In the formula, R represents a hydrogen atom or a methyl group, A represents a hydrogen atom or a fluorine atom, n represents 1 or 2, and m represents an integer of 0 to 5)
(Fluorine-containing compound)
Examples of the fluorine-containing compound represented by the general formula (1) used in the present invention include the following compounds, but the fluorine-containing compound effective in the present invention is not limited thereto.

  The fluorine-containing compound of the present invention preferably has a molecular weight of 350 or less. If the molecular weight exceeds 350, the crosslinking density is lowered, so that sufficient film strength cannot be obtained and durability may be deteriorated. As the polymerizable functional group of the fluorine-containing compound of the present invention, an acryloyl group or a methacryloyl group is preferably used. The addition amount of the fluorine-containing compound of the present invention is preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the polymerizable compound of the present invention. If the amount is less than 0.01 parts by mass, sufficient film strength cannot be obtained, and sufficient surface energy lowering effect may not be obtained. If the amount is more than 1 part by mass, the crosslinking density of the protective layer may be reduced, and sufficient film strength may not be obtained.

  The fluorine-containing compound of the present invention is commercially available or can be easily synthesized by a known method. As a commercial item, Osaka Organic Chemical Industry Co., Ltd. fluorine monomer etc. are mentioned, for example.

(Polymerizable compound)
The polymerizable compound of the present invention has 7 to 10 polymerizable functional groups and has a polymerizable functional group equivalent of 140 or less. The polymerizable functional group equivalent of the present invention is obtained by dividing the molecular weight by the number of polymerizable functional groups. The smaller the polymerizable functional group equivalent, the higher the crosslinking density and the stronger protective layer can be formed. . When the polymerizable functional group equivalent exceeds 140, the film strength of the protective layer is insufficient and sufficient durability cannot be obtained. Moreover, as a polymeric functional group of the polymeric compound of this invention, an acryloyl group and a methacryloyl group are preferable.

  When the number of polymerizable functional groups is 7 or less, the polymerizable functional group equivalent is increased, the crosslinking density is not sufficient, and the film strength of the protective layer is insufficient. When the number is 10 or more, as a result of the decrease in reactivity, unreacted functional groups increase, and the effect of improving the film strength of the protective layer cannot be obtained. The polymerizable compound of the present invention can be easily obtained by obtaining a commercial product or by a known method.

  Although the specific example of the polymeric compound of this invention is illustrated below, the polymeric compound effective for this invention is not limited to these.

  Here, R and R ′ are an acryloyl group and a methacryloyl group represented by the following structural formula.

[Metal oxide fine particles]
The metal oxide fine particles according to the present invention may be metal oxide fine particles including transition metals, such as silica (silicon oxide), magnesium oxide, zinc oxide, lead oxide, alumina (aluminum oxide), tin oxide, Metals such as tantalum oxide, indium oxide, bismuth oxide, yttrium oxide, cobalt oxide, copper oxide, manganese oxide, selenium oxide, iron oxide, zirconium oxide, germanium oxide, tin oxide, titanium dioxide, niobium oxide, molybdenum oxide, vanadium oxide Examples of the oxide fine particles include alumina (Al ₂ O ₃ ), tin oxide (SnO ₂ ), titanium dioxide (TiO ₂ ), and silica (SiO ₂ ), and alumina, tin oxide, and titanium oxide are preferable. The fine particles are more preferable.

  The number average primary particle size of the metal oxide fine particles is preferably in the range of 1 to 300 nm. Especially preferably, it is 3-100 nm.

  The number average primary particle size of the metal oxide fine particles is a photographic image (excluding aggregated particles) obtained by taking an enlarged photograph of 10,000 times with a scanning electron microscope (manufactured by JEOL Ltd.) and randomly capturing 300 particles with a scanner. A) automatic image processing analyzer LUZEX AP (Nireco Corp.) software version Ver. The number average primary particle size was calculated using 1.32.

  The amount of the surface-treated metal oxide fine particles is preferably 20 to 400 parts by mass, and more preferably 50 to 300 parts by mass with respect to 100 parts by mass of the polymerizable compound of the present invention. When the surface-treated metal oxide fine particles are used in an amount of 20 parts by mass or more, the electrical resistance of the protective layer does not become excessively high, and the increase in residual potential and fogging can be prevented. It is good and can prevent a decrease in charging ability and the occurrence of pinholes.

  In addition, the metal oxide fine particles according to the present invention show an effect without being subjected to a surface treatment, but the surface treatment with a surface treatment agent having a reactive organic group allows the bonding with the polymerizable compound of the present invention. It is particularly preferable because it becomes stronger.

[Surface treatment agent]
Next, the surface treating agent used for the surface treatment of the metal oxide fine particles will be described. The surface treatment agent used for the surface treatment of the metal oxide fine particles may be a surface treatment agent having reactivity with a hydroxyl group or the like present on the surface of the metal oxide fine particles. Examples of such reactive surface treatment agents include the compounds described below.

_{S-1: CH 2 = CHSi} (CH 3) (OCH 3) 2
_{S-2: CH 2 = CHSi} (OCH 3) 3
S-3: CH ₂ = CHSiCl _{3
S-4: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-5: CH 2 = CHCOO} (CH 2) 2 Si (OCH 3) 3
_{S-6: CH 2 = CHCOO} (CH 2) 2 Si (OC 2 H 5) (OCH 3) 2
_{S-7: CH 2 = CHCOO} (CH 2) 3 Si (OCH 3) 3
_{S-8: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) Cl 2
_{S-9: CH 2 = CHCOO} (CH 2) 2 SiCl 3
_{S-10: CH 2 = CHCOO} (CH 2) 3 Si (CH 3) Cl 2
S-11: CH ₂ = CHCOO (CH ₂ ) ₃ SiCl _{3
S-12: CH 2 = C} (CH 3) COO (CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-13: CH 2 = C} (CH 3) COO (CH 2) 2 Si (OCH 3) 3
_{S-14: CH 2 = C} (CH 3) COO (CH 2) 3 Si (CH 3) (OCH 3) 2
_{S-15: CH 2 = C} (CH 3) COO (CH 2) 3 Si (OCH 3) 3
_{S-16: CH 2 = C} (CH 3) COO (CH 2) 2 Si (CH 3) Cl 2
_{S-17: CH 2 = C} (CH 3) COO (CH 2) 2 SiCl 3
_{S-18: CH 2 = C} (CH 3) COO (CH 2) 3 Si (CH 3) Cl 2
_{S-19: CH 2 = C} (CH 3) COO (CH 2) 3 SiCl 3
_{S-20: CH 2 = CHSi} (C 2 H 5) (OCH 3) 2
_{S-21: CH 2 = C} (CH 3) Si (OCH 3) 3
_{S-22: CH 2 = C} (CH 3) Si (OC 2 H 5) 3
_{S-23: CH 2 = CHSi} (OCH 3) 3
_{S-24: CH 2 = C} (CH 3) Si (CH 3) (OCH 3) 2
_{S-25: CH 2 = CHSi} (CH 3) Cl 2
_{S-26: CH 2 = CHCOOSi} (OCH 3) 3
_{S-27: CH 2 = CHCOOSi} (OC 2 H 5) 3
_{S-28: CH 2 = C} (CH 3) COOSi (OCH 3) 3
_{S-29: CH 2 = C} (CH 3) COOSi (OC 2 H 5) 3
_{S-30: CH 2 = C} (CH 3) COO (CH 2) 3 Si (OC 2 H 5) 3
_{S-31: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) 2 (OCH 3)
_{S-32: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (OCOCH 3) 2
_{S-33: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (ONHCH 3) 2
_{S-34: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (OC 6 H 5) 2
_{S-35: CH 2 = CHCOO} (CH 2) 2 Si (C 10 H 21) (OCH 3) 2
_{S-36: CH 2 = CHCOO} (CH 2) 2 Si (CH 2 C 6 H 5) (OCH 3) 2
Moreover, as a surface treating agent, you may use the silane compound which has the reactive organic group which can be radically polymerized other than said S-1 to S-36.

  These surface treatment agents can be used alone or in admixture of two or more.

[Preparation of surface-treated metal oxide fine particles]
In carrying out the surface treatment, it is preferable to treat the surface treatment agent using 0.1 to 100 parts by weight of the metal oxide fine particles and 100 to 50 parts by weight of the solvent and 50 to 5000 parts by weight of the solvent using a wet media dispersion type apparatus. . Moreover, it can also process by a dry type.

  Hereinafter, a surface treatment method for producing metal oxide fine particles uniformly surface-treated with a surface treatment agent will be described.

  That is, by subjecting a slurry (suspension of solid particles) containing metal oxide fine particles and a surface treatment agent to wet pulverization, the metal oxide fine particles are refined and at the same time the surface treatment of the fine particles proceeds. Then, the metal oxide fine particles surface-treated with the surface treatment agent can be obtained uniformly by removing the solvent and pulverizing.

  The wet media dispersion type apparatus, which is a surface treatment apparatus used in the present invention, is filled with beads as a medium in a container, and further rotated at high speed a stirring disk attached perpendicularly to the rotation axis, thereby forming a metal oxide. It is an apparatus having a step of crushing and pulverizing / dispersing the aggregated particles, and the configuration is such that the metal oxide fine particles are sufficiently dispersed when the surface treatment is performed on the metal oxide fine particles and the surface treatment can be performed. For example, various types such as a vertical type, a horizontal type, a continuous type, and a batch type can be adopted without any problem. Specifically, a sand mill, ultra visco mill, pearl mill, glen mill, dyno mill, agitator mill, dynamic mill and the like can be used. These dispersion-type devices are pulverized and dispersed by impact crushing, friction, shearing, shear stress, etc., using a grinding medium (media) such as balls and beads.

  As the beads used in the sand grinder mill, a grinding medium made of glass, alumina, zircon, zirconia, steel, flint stone or the like can be used, and those made of zirconia or zircon are particularly preferable. Further, as the size of the beads, those having a diameter of about 1 to 2 mm are usually used, but in the present invention, those having a diameter of about 0.1 to 1.0 mm are preferably used.

  Various materials such as stainless steel, nylon and ceramic can be used for the disk and container inner wall used in the wet media dispersion type apparatus. In the present invention, the disk and container inner wall made of ceramic such as zirconia or silicon carbide are particularly used. Is preferred.

  By the wet treatment as described above, metal oxide fine particles having a reactive organic group capable of reacting with a reactive acryloyl group and a reactive methacryloyl group can be obtained by surface treatment with a surface treating agent.

  Furthermore, the protective layer according to the present invention can be formed by using a known resin together with the compound obtained by the reaction.

  Known resins include polyester resins, polycarbonate resins, polyurethane resins, acrylic resins, epoxy resins, silicone resins, alkyd resins, and the like.

  In addition to these, the protective layer according to the present invention may be formed by containing a polymerization initiator, a filler, lubricant particles and the like as necessary.

(Polymerization initiator)
In the present invention, the protective layer is formed by curing reaction of the polymerizable compound, but the curing reaction is performed by a method using an electron beam cleavage reaction or a method using a radical polymerization initiator in the presence of light or heat. be able to. When the curing reaction is performed using a radical polymerization initiator, any of a photopolymerization initiator and a thermal polymerization initiator can be used as the polymerization initiator. Further, both light and heat initiators can be used in combination.

  Examples of the polymerization initiator that can be used in the present invention include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylazobisvaleronyl), 2,2′-azobis (2 Azo compounds such as -methylbutyronitrile), benzoyl peroxide (BPO), di-tert-butyl hydroperoxide, tert-butyl hydroperoxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, bromomethylbenzoyl peroxide, peroxide Examples thereof include thermal polymerization initiators such as peroxides such as lauroyl.

  Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1 (Irgacure 369: manufactured by BASF Japan Ltd.), 2-hydroxy-2-methyl -1-phenylpropan-1-one, 2-methyl-2-morpholino (4-methylthiophenyl) propan-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, etc. Acetophenone or ketal photoinitiators, benzoin, benzoin methyl ether, Benzoin ether photopolymerization initiators such as zoin ethyl ether, benzoin isobutyl ether, benzoin isopropyl ether, benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoylphenyl Benzophenone photopolymerization initiators such as ether, acrylated benzophenone, 1,4-benzoylbenzene, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichloro Examples thereof include thioxanthone photopolymerization initiators such as thioxanthone.

  Other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine Oxide (Irgacure 819: manufactured by BASF Japan), bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10-phenanthrene, acridine compound, triazine And imidazole compounds. Moreover, what has a photopolymerization acceleration effect can also be used individually or in combination with the said photoinitiator. Examples include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, 4,4′-dimethylaminobenzophenone, and the like.

  The polymerization initiator used in the present invention is preferably a photopolymerization initiator, preferably an alkylphenone compound or a phosphine oxide compound, more preferably an initiator having an α-hydroxyacetophenone structure or an acylphosphine oxide structure. preferable.

  These polymerization initiators may be used alone or in combination of two or more. Content of a polymerization initiator is 0.1-40 mass parts with respect to 100 mass parts of polymeric compounds, Preferably it is 0.5-20 mass parts.

[Lubricant particles]
It is also possible to contain various lubricant particles in the protective layer. For example, fluorine atom-containing resin fine particles can be added. Fluorine atom-containing resin particles include tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluorochloroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride dichloride resin, and these One or two or more types are preferably selected from the copolymers, but tetrafluoroethylene resin and vinylidene fluoride resin are particularly preferable.

〔solvent〕
Solvents used for forming the protective layer include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol, benzyl alcohol, toluene, xylene, methyl ethyl ketone, cyclohexane, ethyl acetate, Examples thereof include, but are not limited to, butyl acetate, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1,3-dioxane, 1,3-dioxolane, pyridine and diethylamine.

(Formation of protective layer)
The protective layer is a photosensitive layer prepared by adding a coating solution prepared by adding a polymerizable compound, surface-treated metal oxide fine particles, and a known resin, a polymerization initiator, a lubricant particle, an antioxidant, and the like, if necessary. It can be prepared by applying to the surface, performing natural drying or heat drying, and then curing.

  As a coating method, a known method such as a dip coating method or a circular amount regulation type coating method can be used. Here, the circular amount regulation type coating method is most preferable.

  The thickness of the protective layer is preferably 0.2 to 10 μm, and more preferably 0.5 to 6 μm.

  In the present invention, the protective layer is cured by irradiating the coating film with active rays to generate radicals and polymerize, and then cure by forming a cross-linking bond between the molecules and within the molecule to form a cured resin. It is preferable to do. The active ray is preferably light such as ultraviolet light or visible light, or an electron beam, and ultraviolet light is particularly preferred from the standpoint of ease of use.

As the ultraviolet light source, any light source that generates ultraviolet light can be used without limitation. For example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a flash (pulse) xenon, an ultraviolet LED, or the like can be used. Irradiation conditions vary depending on each lamp, but the irradiation amount of active rays is usually 1 to 20 mJ / cm ² , preferably 5 to 15 mJ / cm ² . The output voltage of the light source is preferably 0.1 to 5 kW, and particularly preferably 0.5 to 3 kW.

  As an electron beam source, there is no particular limitation on the electron beam irradiation apparatus, and generally, an electron beam accelerator for electron beam irradiation is a curtain beam type that is relatively inexpensive and can provide a large output. Used. The acceleration voltage during electron beam irradiation is preferably 100 to 300 kV. The absorbed dose is preferably 0.005 Gy to 100 kGy (0.5 to 10 Mrad).

  The irradiation time of the active ray is a time for obtaining the necessary irradiation amount of the active ray, specifically 0.1 seconds to 10 minutes is preferable, and 1 second to 5 minutes is more preferable from the viewpoint of curing efficiency or work efficiency. It is said.

  In the present invention, the protective layer can be dried before and after irradiation with active rays and during irradiation with active rays, and the timing of drying can be appropriately selected in combination with the irradiation conditions of active rays. The drying conditions for the protective layer can be appropriately selected depending on the type of solvent used in the coating solution and the thickness of the protective layer. The drying temperature is preferably from room temperature to 180 ° C, particularly preferably from 80 ° C to 140 ° C. The drying time is preferably 1 minute to 200 minutes, and particularly preferably 5 minutes to 100 minutes.

[Photosensitive layer structure]
The photoreceptor of the present invention is obtained by forming a photosensitive layer and a protective layer on a conductive support. The layer structure of the photosensitive layer is not particularly limited, and examples of the specific layer structure including the protective layer include the following.
(1) Layer configuration in which a charge generation layer, a charge transport layer, and a protective layer are sequentially laminated on a conductive support. (2) A single layer containing a charge transport material and a charge generation material on a conductive support. Layer structure in which layer and protective layer are sequentially laminated (3) Layer structure in which intermediate layer, charge generation layer, charge transport layer and protective layer are sequentially laminated on conductive support (4) Conductive support A layer structure in which an intermediate layer, a single layer containing a charge transporting material and a charge generating material, and a protective layer are sequentially laminated on the photosensitive member of the present invention has any one of the above-mentioned layer structures (1) to (4). Among them, a layer structure in which an intermediate layer, a charge generation layer, a charge transport layer, and a protective layer are sequentially provided on a conductive support is particularly preferable.

  FIG. 1 is a schematic view showing an example of the layer structure of the photoreceptor of the present invention.

  In FIG. 1, 1 is a conductive support, 2 is a photosensitive layer, 3 is an intermediate layer, 4 is a charge generation layer, 5 is a charge transport layer, 6 is a protective layer, and 7 is a surface-treated metal oxide fine particle.

  Next, the conductive support, the photosensitive layer (intermediate layer, charge generation layer, charge transport layer) constituting the photoreceptor of the present invention and the members constituting the photosensitive layer will be described.

[Conductive support]
The support used in the present invention may be any one as long as it has conductivity, for example, a metal such as aluminum, copper, chromium, nickel, zinc and stainless steel formed into a drum or sheet, aluminum Metal foil such as copper or copper laminated on plastic film, aluminum, indium oxide or tin oxide deposited on plastic film, metal or plastic with conductive layer applied alone or with binder resin Examples include film and paper.

[Middle layer]
In the present invention, an intermediate layer having a barrier function and an adhesive function can be provided between the conductive support and the photosensitive layer. The intermediate layer can be formed by dip coating or the like by dissolving a binder resin such as casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide, polyurethane and gelatin in a known solvent. Among the binder resins, an alcohol-soluble polyamide resin is preferable.

  The intermediate layer may contain various conductive fine particles and metal oxide fine particles for the purpose of adjusting the resistance. For example, various metal oxide fine particles such as alumina, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, and bismuth oxide. Ultrafine particles such as indium oxide doped with tin, tin oxide doped with antimony, and zirconium oxide can be used. These metal oxide fine particles can be used alone or in combination. When two or more kinds are mixed and used, they may take the form of a solid solution or fusion. Such metal oxide fine particles preferably have a number average primary particle size of 0.3 μm or less, more preferably 0.1 μm or less.

  As the solvent that can be used for forming the intermediate layer, a solvent in which inorganic fine particles such as the conductive fine particles and metal oxide fine particles described above are well dispersed and a binder resin such as a polyamide resin is dissolved is preferable. Specifically, with respect to the polyamide resin, alcohols having 2 to 4 carbon atoms such as ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol and the like are preferable as the binder resin. It is preferable because good solubility and coating performance are exhibited. Further, in order to improve the storage stability and the dispersibility of the inorganic fine particles, the following cosolvent can be used in combination with the solvent. Examples of the co-solvent that can provide a preferable effect include methanol, benzyl alcohol, toluene, cyclohexanone, tetrahydrofuran, and the like.

  The binder resin concentration at the time of forming the coating solution can be appropriately selected according to the film thickness of the intermediate layer and the coating method. Moreover, when inorganic fine particles etc. are disperse | distributed, it is preferable that the mixing rate of the inorganic fine particles with respect to binder resin shall be 20-400 mass parts with respect to 100 mass parts of binder resin, and shall be 50-200 parts. Is more preferable.

  Examples of the means for dispersing the inorganic fine particles include, but are not limited to, an ultrasonic disperser, a ball mill, a sand grinder, and a homomixer.

  Moreover, the drying method of an intermediate | middle layer can select suitably a well-known drying method according to the kind of solvent and the film thickness to form, and heat drying is especially preferable.

  The thickness of the intermediate layer is preferably from 0.1 to 15 μm, more preferably from 0.3 to 10 μm.

(Photosensitive layer)
As described above, the photosensitive layer constituting the photoreceptor of the present invention has a charge generation layer (CGL) and a charge transport layer (CTL) in addition to a single layer structure in which a charge generation function and a charge transport function are provided in one layer. And a layer structure in which the functions of the photosensitive layer are separated from each other. As described above, the function-separated type layer structure has an advantage that it is easy to control various electrophotographic characteristics according to the purpose, in addition to being able to control the increase in residual potential with repeated use. The negatively chargeable photoreceptor has a structure in which a charge generation layer (CGL) is provided on an intermediate layer and a charge transport layer (CTL) is provided thereon. The positively chargeable photoreceptor is a charge transport layer (CTL) provided on the intermediate layer. The charge generation layer (CGL) is provided thereon. A preferred layer structure of the photosensitive layer is a negatively charged photoreceptor having the function separation structure.

  Below, each layer of the photosensitive layer of the function-separated negatively charged photoreceptor is described as a specific example of the photosensitive layer.

(Charge generation layer)
The charge generation layer formed in the present invention contains a charge generation material and a binder resin, and is preferably formed by applying a coating solution in which the charge generation material is dispersed in a binder resin solution.

  Charge generation materials include azo raw materials such as Sudan Red and Diane Blue, quinone pigments such as pyrenequinone and anthanthrone, quinocyanine pigments, perylene pigments, indigo pigments such as indigo and thioindigo, phthalocyanine pigments, and the like. is not. These charge generation materials can be used alone or in a form dispersed in a known binder resin.

  As the binder resin for forming the charge generation layer, known resins can be used. For example, polystyrene resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy Resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, and copolymer resin containing two or more of these resins (for example, vinyl chloride-vinyl acetate copolymer resin) , Vinyl chloride-vinyl acetate-maleic anhydride copolymer resin) and polyvinyl carbazole resin, but are not limited thereto.

  The charge generation layer is formed by dispersing the charge generation material in a solution obtained by dissolving the binder resin in a solvent using a disperser to prepare a coating solution, and applying the coating solution to a certain film thickness using a coating device. It is preferable to prepare the film by drying.

  Solvents for dissolving and coating the binder resin used in the charge generation layer include, for example, toluene, xylene, methyl ethyl ketone, cyclohexane, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, methyl cellosolve, ethyl cellosolve, tetrahydrofuran , 1-dioxane, 1,3-dioxolane, pyridine, diethylamine and the like, but are not limited thereto.

  As a means for dispersing the charge generating material, an ultrasonic disperser, a ball mill, a sand grinder, a homomixer, or the like can be used, but is not limited thereto.

  The mixing ratio of the charge generating material to the binder resin is preferably 1 to 600 parts by weight, more preferably 50 to 500 parts by weight based on 100 parts by weight of the binder resin. The thickness of the charge generation layer varies depending on the characteristics of the charge generation material, the characteristics of the binder resin, the mixing ratio, and the like, but is preferably 0.01 to 5 μm, and more preferably 0.05 to 3 μm. It should be noted that the coating solution for the charge generation layer can prevent the occurrence of image defects by filtering foreign matter and aggregates before coating. The pigment can also be formed by vacuum deposition.

(Charge transport layer)
The charge transport layer formed in the present invention contains at least a charge transport material and a binder resin in the layer, and is formed by dissolving and coating the charge transport material in a binder resin solution.

  As the charge transport material, a known compound can be used, and examples thereof include the following. Carbazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds, pyrazoline compounds, oxazolone derivatives, benz Imidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, phenylenediamine derivatives, stilbene derivatives, benzidine derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene and poly-9 -Vinylanthracene and the like. These compounds can be used alone or in admixture of two or more.

  Further, a known resin can be used as the binder resin for the charge transport layer, and examples thereof include the following. That is, polycarbonate resin, polyacrylate resin, polyester resin, polystyrene resin, styrene-acrylonitrile copolymer resin, polymethacrylic acid ester resin, styrene-methacrylic acid ester copolymer resin, and the like. Of these, polycarbonate resins are preferable, and polycarbonate resins of the types such as bisphenol A (BPA), bisphenol Z (BPZ), dimethyl BPA, and BPA-dimethyl BPA copolymer are crack resistant, wear resistant, and charging characteristics. From the viewpoint of

  The charge transport layer can be formed by a known method typified by a coating method. For example, in the coating method, a binder resin and a charge transport material are dissolved to prepare a coating solution, and the coating solution is formed into a certain film. A desired charge transport layer can be formed by drying after coating with a thickness.

  Examples of the solvent for dissolving the binder resin and the charge transport material include toluene, xylene, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, tetrahydrofuran, 1,4-dioxane, 1,3- And dioxolane. The solvent used when preparing the coating liquid for forming the charge transport layer is not limited to the above.

  The mixing ratio of the binder resin and the charge transport material is preferably 10 to 500 parts by weight, and more preferably 20 to 100 parts by weight with respect to 100 parts by weight of the binder resin.

  The thickness of the charge transport layer varies depending on the characteristics of the charge transport material and the binder resin, the mixing ratio thereof, and the like, but is preferably 5 to 40 μm, and more preferably 10 to 30 μm.

  In the charge transport layer, a known antioxidant can be added. For example, an antioxidant described in JP-A-2000-305291 can be used.

  In addition, each layer such as an intermediate layer, a charge generation layer, a charge transport layer, and a protective layer constituting the photoreceptor of the present invention can be formed by a known coating method. Specific examples include a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a blade coating method, a beam coating method, and a circular amount-regulating coating method. The circular amount regulation type coating method is described in JP-A-58-189061.

<Image forming apparatus>
An image forming apparatus according to the present invention will be described.

An image forming apparatus that realizes the effects of the present invention is as follows.
(1) An electrophotographic photosensitive member having at least the protective layer of the present invention,
(2) Charging means for charging the surface of the electrophotographic photosensitive member described above,
(3) An exposure unit that performs image exposure on the surface of the electrophotographic photosensitive member charged by the charging unit to form a latent image; a developing unit that visualizes the latent image formed by the exposure unit and forms a toner image;
(4) The image forming apparatus includes a transfer unit that transfers the toner image formed on the surface of the electrophotographic photosensitive member by the developing unit onto a transfer medium such as paper or a transfer belt.

  Note that a non-contact charging device is preferably used as the charging means for charging the electrophotographic photosensitive member. Examples of the non-contact charging device include a corona charging device, a corotron charging device, and a scorotron charging device.

  FIG. 2 is a cross-sectional configuration diagram of a color image forming apparatus showing one embodiment of the present invention.

  This color image forming apparatus is called a tandem type color image forming apparatus, and includes four sets of image forming units (image forming units) 10Y, 10M, 10C, and 10Bk, an endless belt-shaped intermediate transfer body unit 7, and a feeding unit. It comprises a paper conveying means 21 and a fixing means 24. A document image reading device SC is disposed on the upper part of the main body A of the image forming apparatus.

  The image forming unit 10Y that forms a yellow image includes a charging unit (charging step) 2Y, an exposure unit (exposure step) 3Y, and a developing unit disposed around a drum-shaped photoconductor 1Y as a first image carrier. A unit (developing step) 4Y, a primary transfer roller 5Y as a primary transfer unit (primary transfer step), and a cleaning unit 6Y. An image forming unit 10M that forms a magenta image includes a drum-shaped photosensitive member 1M as a first image carrier, a charging unit 2M, an exposure unit 3M, a developing unit 4M, a primary transfer roller 5M as a primary transfer unit, It has a cleaning means 6M. An image forming unit 10C for forming a cyan image includes a drum-shaped photoreceptor 1C as a first image carrier, a charging unit 2C, an exposure unit 3C, a developing unit 4C, and a primary transfer roller 5C as a primary transfer unit. It has cleaning means 6C. The image forming unit 10Bk that forms a black image includes a drum-shaped photoreceptor 1Bk as a first image carrier, a charging unit 2Bk, an exposure unit 3Bk, a developing unit 4Bk, a primary transfer roller 5Bk as a primary transfer unit, and a cleaning unit. 6Bk.

  The four sets of image forming units 10Y, 10M, 10C, and 10Bk include charging means 2Y, 2M, 2C, and 2Bk that rotate around the photosensitive drums 1Y, 1M, 1C, and 1Bk, and image exposure means 3Y, 3M, 3C and 3Bk, rotating developing means 4Y, 4M, 4C and 4Bk, and cleaning means 6Y, 6M, 6C and 6Bk for cleaning the photosensitive drums 1Y, 1M, 1C and 1Bk.

  The image forming units 10Y, 10M, 10C, and 10Bk have the same configuration except that the colors of toner images formed on the photoreceptors 1Y, 1M, 1C, and 1Bk are different, and the image forming unit 10Y is taken as an example in detail. explain.

  The image forming unit 10Y has a charging unit 2Y (hereinafter simply referred to as a charging unit 2Y or a charger 2Y), an exposure unit 3Y, a developing unit 4Y, and a cleaning unit 6Y (around a photosensitive drum 1Y as an image forming body). Hereinafter, the cleaning unit 6Y or the cleaning blade 6Y) is simply disposed, and a yellow (Y) toner image is formed on the photosensitive drum 1Y. In the present embodiment, in the image forming unit 10Y, at least the photosensitive drum 1Y, the charging unit 2Y, the developing unit 4Y, and the cleaning unit 6Y are provided so as to be integrated.

  The charging unit 2Y is a unit that applies a uniform potential to the photosensitive drum 1Y. In the present embodiment, a corona discharge type charger 2Y is used for the photosensitive drum 1Y.

  The image exposure means 3Y performs exposure based on the image signal (yellow) on the photosensitive drum 1Y given a uniform potential by the charger 2Y, and forms an electrostatic latent image corresponding to the yellow image. As the exposure means 3Y, the exposure means 3Y includes an LED in which light emitting elements are arranged in an array in the axial direction of the photosensitive drum 1Y and an imaging element (trade name; Selfoc lens), or A laser optical system or the like is used.

  The image forming apparatus of the present invention is configured by integrally combining the above-described photosensitive member and components such as a developing device and a cleaning device as a process cartridge (image forming unit), and this image forming unit is connected to the apparatus main body. It may be configured to be detachable. In addition, at least one of a charging device, an image exposure device, a developing device, a transfer or separation device, and a cleaning device is integrally supported together with a photosensitive member to form a process cartridge (image forming unit), which is detachable from the apparatus main body. A single image forming unit may be detachable using guide means such as a rail of the apparatus main body.

  The endless belt-like intermediate transfer body unit 7 includes an endless belt-like intermediate transfer body 70 as a second image carrier having a semiconductive endless belt shape that is wound around a plurality of rollers and is rotatably supported.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10Bk is sequentially transferred onto a rotating endless belt-shaped intermediate transfer body 70 by primary transfer rollers 5Y, 5M, 5C, and 5Bk as primary transfer means. Thus, a synthesized color image is formed. A transfer material P as a transfer material (a support for carrying a fixed final image: for example, plain paper, a transparent sheet, etc.) housed in the paper feed cassette 20 is fed by a paper feed means 21 and a plurality of intermediates. After passing through rollers 22A, 22B, 22C, 22D and registration roller 23, they are conveyed to a secondary transfer roller 5b as a secondary transfer means, and are secondarily transferred onto a transfer material P to transfer a color image all at once. The transfer material P onto which the color image has been transferred is subjected to fixing processing by the fixing unit 24, is sandwiched between paper discharge rollers 25, and is placed on a paper discharge tray 26 outside the apparatus. Here, a transfer support for a toner image formed on a photosensitive member such as an intermediate transfer member or a transfer material is collectively referred to as a transfer medium.

  On the other hand, after the color image is transferred to the transfer material P by the secondary transfer roller 5b as the secondary transfer means, the residual toner is removed by the cleaning means 6b from the endless belt-shaped intermediate transfer body 70 in which the transfer material P is separated by curvature. The

  During the image forming process, the primary transfer roller 5Bk is always in contact with the photoreceptor 1Bk. The other primary transfer rollers 5Y, 5M, and 5C are in contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roller 5b contacts the endless belt-shaped intermediate transfer body 70 only when the transfer material P passes through the secondary transfer roller 5b.

  Further, the housing 8 can be pulled out from the apparatus main body A through the support rails 82L and 82R.

  The housing 8 includes image forming units 10Y, 10M, 10C, and 10Bk and an endless belt-shaped intermediate transfer body unit 7.

  The image forming units 10Y, 10M, 10C, and 10Bk are arranged in tandem in the vertical direction. An endless belt-shaped intermediate transfer body unit 7 is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1Bk in the drawing. The endless belt-shaped intermediate transfer body unit 7 includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rollers 71, 72, 73, 74, primary transfer rollers 5Y, 5M, 5C, 5Bk, and cleaning means 6b. Consists of.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

(Synthesis example)
(Synthesis of polymerizable compounds M1 and M3)
The following method can be used, and M1 and M3 are described as examples.

  The reactor was charged with 100 g of tripentaerythritol, 162 g of acrylic acid, 91 g of cyclohexane, 8.0 g of concentrated sulfuric acid, and 1.2 g of hydroquinone monomethyl ether, and reacted at 80 ° C. to 90 ° C. for 8 hours while blowing air at 10 ml / min. After completion of the reaction, 530 g of toluene was added to the reaction mixture, and the resulting organic layer was washed with a 25% by mass aqueous sodium hydroxide solution and then with a 10% by mass aqueous sodium sulfate solution, dried using magnesium sulfate, and then a polymerization inhibitor ( Hydroquinone monomethyl ether) 0.2 g was added, concentrated, and dried to obtain 183 g of tripentaerythritol polyacrylate. The obtained tripentaerythritol polyacrylate is usually obtained as a mixture of tripentaerythritol hexaacrylate, tripentaerythritol heptaacrylate (M3), tripentaerythritol octaacrylate (M1), etc., but by fractionating each, 100 g of tripentaerythritol octaacrylate (M1) and 83 g of tripentaerythritol heptaacrylate (M3) were obtained. Can be separated.

(Production of surface-treated metal oxide)
(Preparation of surface-treated metal oxide fine particles 1)
100 parts by mass of “tin oxide” having a number average primary particle size of 20 nm as metal oxide fine particles, 30 parts by mass of “Exemplary Compound S-4” as a surface treatment agent, and 1000 parts by mass of methyl ethyl ketone were wet sand mill (alumina beads having a diameter of 0.5 mm). ) And mixed at 30 ° C. for 6 hours, and then methyl ethyl ketone and alumina beads were separated by filtration and dried at 60 ° C. to prepare “surface-treated metal oxide fine particles 1”.

(Preparation of surface-treated metal oxide fine particles 2)
In the production of the surface-treated metal oxide fine particles 1, “surface-treated metal oxide fine particles 2” were produced in the same manner except that “Exemplary Compound S-3” was used as the surface treatment agent.

(Preparation of surface-treated metal oxide fine particles 3)
In the preparation of the surface-treated metal oxide fine particles 1, “surface” was used in the same manner except that “alumina” having a number average primary particle size of 30 nm was used as the metal oxide fine particles and “Exemplary Compound S-6” was used as the surface treatment agent. Treated metal oxide fine particles 3 ”were prepared.

(Preparation of surface-treated metal oxide fine particles 4)
“Surface-treated metal oxide fine particles 4” were produced in the same manner as in the preparation of the surface-treated metal oxide fine particles 3 except that the surface treatment agent was changed to “Exemplary Compound S-4”.

(Preparation of surface-treated metal oxide fine particles 5)
In the preparation of the surface-treated metal oxide fine particles 1, “titanium dioxide” having a number average primary particle size of 30 nm was used as the metal oxide fine particles, and the surface treatment agent was changed to “Exemplary Compound S-29”. Surface-treated metal oxide fine particles 5 ”were prepared.

(Preparation of surface-treated metal oxide fine particles 6)
In the preparation of the surface-treated metal oxide fine particles 1, “surface” was used in the same manner except that “alumina” having a number average primary particle size of 30 nm was used as the metal oxide fine particles and “exemplary compound S-4” was used as the surface treatment agent. Treated metal oxide fine particles 6 ”were produced.

(Production of photoconductor)
<Preparation of Photoreceptor 1>
(Preparation of conductive support)
The surface of the cylindrical aluminum support was cut to prepare a conductive support having a surface roughness Rz = 1.5 (μm).

<Formation of intermediate layer>
A dispersion having the following composition was diluted twice with the same mixed solvent, allowed to stand overnight, and then filtered (filter; using a lysh mesh 5 μm filter manufactured by Nippon Pole Co., Ltd.) to prepare an intermediate layer coating solution.

Polyamide resin (CM8000: manufactured by Toray Industries, Inc.) 1 part by mass Titanium oxide (SMT500SAS: manufactured by Teica) 3 parts by mass Methanol 10 parts by mass Using a sand mill as a disperser, dispersion was carried out for 10 hours in a batch system.

  The said coating liquid was apply | coated and dried by the dip coating method so that it might become a dry film thickness of 2 micrometers on the said electroconductive support body, and the "intermediate layer" was formed.

<Formation of charge generation layer>
The following compositions were mixed and dispersed for 10 hours using a sand mill to prepare a charge generation layer coating solution.

Charge generation material: titanyl phthalocyanine pigment (titanyl phthalocyanine pigment having a maximum diffraction peak at a position of at least 27.3 ° by Cu-Kα characteristic X-ray diffraction spectrum measurement) 20 parts by mass Polyvinyl butyral resin (# 6000-C: electrochemical 10 parts by mass t-butyl acetate 700 parts by mass 4-methoxy-4-methyl-2-pentanone 300 parts by mass This charge generation layer coating solution is applied onto the intermediate layer by a dip coating method and dried. Then, a “charge generation layer” having a dry film thickness of 0.3 μm was formed.

<Formation of charge transport layer>
The following composition was mixed and dissolved to prepare a charge transport layer coating solution.

Charge transport material (4,4′-dimethyl-4 ″-(β-phenylstyryl) triphenylamine) 225 parts by mass Polycarbonate (Z300: manufactured by Mitsubishi Gas Chemical Company) 300 parts by mass Antioxidant (Irganox 1010: manufactured by BASF Japan) ) 6 parts by mass Tetrahydrofuran 1600 parts by mass Toluene 400 parts by mass Silicone oil (KF-54: manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by mass This charge transport layer coating solution is applied onto the charge generation layer using a circular amount regulating type coating machine. It was applied and dried to form a “charge transport layer” having a dry film thickness of 20 μm.

<Formation of protective layer>
The following composition was dissolved and dispersed to prepare a protective layer coating solution.

Surface-treated metal oxide fine particles 1 100 parts by mass Polymerizable compound (M4) 100 parts by mass Fluorine-containing compound (F-2) 0.01 parts by mass Polymerization initiator (Irgacure 819: manufactured by BASF Japan) 7.5 parts by mass 100 parts by mass of sec-butyl alcohol This protective layer coating solution was applied on the charge transport layer using a circular amount regulating type coating device to form a protective layer.

  After drying the formed protective layer, using a metal halide lamp, the distance from the light source to the surface of the photoreceptor is set to 100 mm under a nitrogen stream, irradiated with ultraviolet light for 1 minute at a lamp output of 4 kW, and a dry film thickness of 2.0 μm. A “protective layer” was formed to produce “photoreceptor 1”.

<Preparation of photoconductors 2 to 17>
“Photoconductors 2 to 17” were similarly prepared except that the types and addition amounts of the surface-treated metal oxide fine particles, the polymerizable compound, and the fluorine-containing compound used in the production of the protective layer of the photoconductor 1 were changed as shown in Table 1. Was made.

(Preparation of photoconductor for comparison)
<Preparation of Photoconductor 18>
In the production of the photoreceptor 1, a photoreceptor 18 was produced in the same manner except that M13 having 6 polymerizable functional groups represented by the following structural formula was used as the polymerizable compound of the protective layer.

<Preparation of photoconductor 19>
In the production of the photoreceptor 1, except that the fluorine-containing compound used in the production of the protective layer was changed to a fluorine-containing compound (F-19) having a structural formula outside the present invention represented by the following structural formula, A photoreceptor 19 was produced.

<Preparation of Photoreceptor 20>
Photoconductor 20 was prepared in the same manner except that surface-treated metal oxide fine particles 4 used in the preparation of the protective layer were used, F-1 was used as the fluorine-containing compound, and no polymerizable compound was added. Was made.

<Preparation of Photoreceptor 21>
The surface treatment metal oxide fine particles 2 used in the production of the protective layer in the production of the photoreceptor 1 were used, and M15 having 12 polymerizable functional groups represented by the following structural formula was used as the polymerizable compound. Thus, a photoreceptor 21 was produced.

<Preparation of Photoconductor 22>
Photoconductor 22 was prepared in the same manner except that the protective layer was changed to the following formulation in preparation of photoconductor 1.

Surface treated metal oxide fine particles 6 200 parts by weight Polymerizable compound (M14: polymerizable functional group equivalent 155) 100 parts by weight Fluorine-containing compound (F-4) 0.5 parts by weight Polymerization initiator (Irgacure 369: BASF Japan Ltd.) 15 parts by mass 1-propyl alcohol 500 parts by mass

  As described above, the photoconductors 18 to 22 were used as comparative photoconductors.

(Evaluation and criteria)
The photoreceptors 1 to 17 of the present invention and the comparative photoreceptors 18 to 22 produced as described above were evaluated as follows.

(Abrasion resistance evaluation)
The electrophotographic photosensitive member of the present invention is mounted on “bizhub PRO C6500” (tandem color composite machine of laser exposure / reversal development / intermediate transfer member having a wavelength of 780 nm) manufactured by Konica Minolta Business Technologies, Inc. (30 ° C., 80% RH). ) Printing yellow sheets (Y), magenta (M), cyan (C), and black (Bk) with an A4 size image of 5% on each A4 size neutral paper, before and after printing. From the measurement of the film thickness of the photoconductor, the wear amount of the protective layer was calculated, and the following evaluation was performed. The film thickness of the photoconductor was measured using a Fischer Scope (registered trademark) MMS (registered trademark) manufactured by Fischer Instruments. The film thickness was compared with the average value of four.

(Wear resistance criteria)
◎: Wear amount less than 0.3 μm ○: Wear amount is 0.3 μm or more and less than 0.5 μm △: Wear amount is 0.5 μm or more and less than 1.0 μm ×: Wear amount is 1.0 μm or more did.

(Image blur evaluation)
The electrophotographic photosensitive member of the present invention is mounted on “bizhub PRO C6500” (tandem color composite machine of laser exposure / reversal development / intermediate transfer member having a wavelength of 780 nm) manufactured by Konica Minolta Business Technologies, Inc. (30 ° C., 80% RH). ), Print 25,000 sheets of A4 plate image with 5% printing area ratio for each color of yellow (Y), magenta (M), cyan (C), black (Bk) on A4 plate neutral paper The main power of the actual machine was stopped 60 seconds later. Immediately after the power was turned on 12 hours after the stop, a halftone image (relative reflection density 0.4 by Macbeth densitometer) and a 6 dot lattice image of the entire A3 plate were printed on the entire surface of the A3 neutral paper. The state of the printed image was observed and the following evaluation was performed.

(Image blur criteria)
◎: No blurring in halftone and grid images (good)
○: A thin strip-like density decrease in the longitudinal direction of the photoreceptor is observed only in the halftone image (no problem in practical use)
Δ: A strip-like density decrease in the long axis direction of the photoconductor is observed only in the halftone image (practical use possible)
×: Lattice image loss or line width narrowing due to image blurring (practical problem)
(Durability evaluation)
After the above evaluation, an A4 plate image having a color printing ratio of 5% for each of yellow (Y), magenta (M), cyan (C), and black (Bk) at 30 ° C. and 80% RH is printed on neutral A4 paper. Image blurring was similarly evaluated again after printing 1 million sheets.

  The results are shown in Table 2. As is apparent from the results in Table 2, the photoconductor of the present invention has extremely excellent durability in terms of abrasion resistance and image blur after copying 25,000 sheets and 1 million sheets as compared with the photoconductor for comparison. It can be seen that the photoconductor has

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Photosensitive layer 3 Intermediate | middle layer 4 Charge generation layer 5 Charge transport layer 6 Protective layer 7 Surface treatment metal oxide fine particle 1Y, 1M, 1C, 1Bk Photosensitive drum 2Y, 2M, 2C, 2Bk Charging means 3Y, 3M, 3C, 3Bk Image exposure means 4Y, 4M, 4C, 4Bk Developing means 6Y, 6M, 6C, 6Bk Cleaning means 10Y, 10M, 10C, 10Bk Image forming unit

Claims (4)

In an electrophotographic photosensitive member formed by sequentially laminating at least a photosensitive layer and a protective layer on a conductive support, the protective layer contains a fluorine-containing compound represented by the following general formula (1) and the number of polymerizable functional groups in one molecule. 7 to 10 and contains a polymerization product with a polymerizable compound having a polymerizable functional group equivalent of 140 or less.

(In the formula, R represents a hydrogen atom or a methyl group, A represents a hydrogen atom or a fluorine atom, n represents 1 or 2, and m represents an integer of 0 to 5)   2. The electrophotographic photoreceptor according to claim 1, wherein the polymerizable compound is a polymerizable monomer or polymerizable oligomer having an acryloyl group or a methacryloyl group as a polymerizable functional group.   The electrophotographic photosensitive member according to claim 1, wherein the protective layer contains metal oxide fine particles.   The metal oxide fine particles are surface-treated with a compound having either an acryloyl group or a methacryloyl group, and the metal oxide fine particles are selected from alumina fine particles, tin oxide fine particles, or titanium oxide fine particles. The electrophotographic photosensitive member according to claim 3, wherein the electrophotographic photosensitive member is one type.

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