JP3273258B2 - Electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positively charged electrophotographic photosensitive member having a charge transport layer, a charge generating layer and a surface protective layer on a conductive support in this order.

[0002]

2. Description of the Related Art Conventionally, in order to form an image by an electrophotographic method, a so-called Carlson method is generally used. An electrostatic latent image is formed by uniformly charging the surface of a photoreceptor and imagewise exposure. The latent image is developed to form a toner image, which is transferred and fixed on a transfer material to form an image.

On the other hand, the photoreceptor after the transfer is subjected to static elimination by a static eliminator and removal of residual toner by rubbing of a cleaning member such as a cleaning blade or a cleaning brush, and is repeatedly used for a long time.

Accordingly, the electrophotographic photoreceptor has not only electrophotographic characteristics such as good charging characteristics and sensitivity and low dark decay, but also printing durability and abrasion resistance in repeated use.
Good physical properties such as moisture resistance, resistance to ozone generated during corona discharge, and resistance to ultraviolet light during exposure (environmental resistance) are also required.

Conventionally, selenium,
Inorganic photoreceptors having a photosensitive layer mainly containing an inorganic photoconductive substance such as zinc oxide and cadmium sulfide are widely used.

On the other hand, the use of various organic photoconductive substances as materials for photosensitive layers of electrophotographic photosensitive members has been actively developed and studied in recent years.

For example, Japanese Patent Publication No. 50-10496 describes an organic photoreceptor having a photosensitive layer containing poly-N-vinylcarbazole and 2,4,7-trinitro-9-fluorenone. However, this photoreceptor is not always satisfactory in sensitivity and durability.

In order to remedy such a drawback, an organic photoreceptor having high sensitivity and high durability is developed by separately assigning a charge generation function and a charge transport function to different substances in the photosensitive layer. Attempts have been made. In such a so-called function-separated type electrophotographic photoreceptor,
Since a material exhibiting each function can be selected from a wide range, an electrophotographic photosensitive member having arbitrary characteristics can be relatively easily produced. According to such an organic electrophotographic photoreceptor, the photosensitive layer can be formed by coating, so that the production cost is low, pollution and environmental pollution can be prevented, and processing into various shapes (sheet shape or the like) can be easily performed.

However, the organic electrophotographic photosensitive member has the following disadvantages, and there is a strong demand for solving these disadvantages.

(A) For example, since a layer is formed by binding a low molecular weight organic compound with a high molecular weight organic resin (binder), the mechanical strength is not always sufficient, and when the photoreceptor is used repeatedly, The surface of the photoreceptor is scratched or abraded by the rubbing of the developing blade or the like.

(B) The photoreceptor is mainly used for negative charging. As described in JP-A-60-247647, a thin charge generation layer is provided on a support, and a relatively thick charge transport layer is provided thereon. A configuration is provided in which a layer is provided.

[0012] The reason for this is that, in the case of negative charging, a hole transporting material can be used, which is advantageous in terms of high sensitivity and the like, whereas an electron transporting material has excellent characteristics. Is extremely low, has toxicity or carcinogenicity, and cannot be used.

In addition, when the photosensitive member is negatively charged using the above-described hole transporting material, a large amount of ozone is generated at the time of charging, thereby deteriorating environmental conditions. Further, the ozone and other ionic substances are adsorbed on the surface of the photoreceptor to deteriorate the material, and repeated use thereof causes a decrease in potential, a rise in residual potential, a decrease in sensitivity, and a decrease in image quality, and shortens the life of the photoreceptor. .

Therefore, research and development of a positively charged photosensitive member comprising a charge transporting layer containing a charge transporting substance having a hole transporting property provided on a support and a charge generating layer provided thereon as a surface layer have been conducted. . According to the photoconductor for positive charging, generation of ozone at the time of charging is extremely small, which is advantageous in environmental hygiene.

However, the charge generation layer provided as the surface layer contains a fine particle-like charge generation substance at a high density,
There is a problem that wear and deterioration easily occur due to mechanical shock, changes in temperature and humidity conditions, and the like.

Therefore, for example, JP-A-2-189550, JP-A-2-89551, JP-A-2-236555, JP-A-2-23
No. 6556, JP-A-2-240655, etc., as the binder resin of the surface layer of the photoreceptor, various substituted polycarbonates, cyclic polycarbonate containing a central carbon atom, polycarbonate having a silicon atom as a central atom, polycarbonate-poly Various polycarbonates such as a siloxane block copolymer have been proposed.

It has been pointed out that these polycarbonates are excellent in dispersibility and film properties of a charge generating substance, resistant to photoelectric fatigue deterioration due to repeated charge exposure, and excellent in mechanical abrasion resistance.

However, in recent copying machines and the like,
High speed, high durability, and high image quality have been demanded, and therefore, further improvement in the film strength of the photoreceptor surface layer has been demanded.

By the way, one measure for the film strength of the photoconductor surface layer is as follows.
For example, Japanese Unexamined Patent Publication (Kokai) No. 61-117558 discloses that SiO ₂ , CrO ₂ , Al ₂ O ₃ , SiC, TiO ₂ , ZnO are used as reinforcing agents in a photosensitive layer.
It has been proposed to incorporate inorganic compound particles such as these.

Further, JP-A-63-30850 and JP-A-64-3
Japanese Patent No. 5448 describes a technique for incorporating a solid lubricant and silicone oil into the surface layer of a photoreceptor. Further, JP-A-2-189550 and JP-A-2-189551 propose a technique in which a polycarbonate resin and a fluorine resin or fluorine resin particles are contained in a surface layer of a photoreceptor.

However, a positively charged organic photoreceptor containing an organic photoconductive pigment at a high density and having a thin charge generating layer as a surface layer has achieved high durability and high image quality recently required. It is not sufficient to perform the process, and the surface of the photosensitive layer is worn and damaged in the process of repeated image formation, and the occurrence of image defects such as image blur and image unevenness is unavoidable. It is rare.

[0022]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrophotographic photoreceptor for positive charging capable of obtaining a high-quality copy image without causing surface abrasion, scratches and image blur due to friction.

It is another object of the present invention to provide a highly durable electrophotographic photosensitive member which has good cleaning properties and does not cause image deterioration due to toner filming on the surface layer of the photosensitive member.

Still another object of the present invention is to provide a positively charged electrophotographic photoreceptor capable of stably obtaining high density and clear image quality without fogging due to an increase in residual potential in the process of repeated image formation. Is to provide.

[0025]

According to the present invention, there is provided an electrophotographic photosensitive member comprising a charge transport layer, a charge generation layer and a surface protective layer laminated in this order on a conductive support, wherein a thermosetting resin is contained in the surface protective layer. And fluorine atom-containing fine particles as a lubricant having a diameter of 0.01 to 3 μm, and selected from silicone resin fine particles, benzoguanamine resin fine particles, metal oxide powder, inorganic whiskers, acrylic resin fine particles, and melamine resin fine particles. The electrophotographic photoreceptor is characterized by containing at least one reinforcing agent and an antioxidant. In a preferred embodiment of the present invention, the thermosetting resin is a silicone resin, an acrylic resin, a phosphazene resin,
Polyester resins, melamine resins, more configured electrophotographic photoreceptor any one or a mixture of these phenol resins Ru is contained.

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

The drawings are schematic sectional views for explaining the layer constitution of the electrophotographic photosensitive member of the present invention. 1 and 2, 1 is a conductive support, 2 is a charge transport layer, 3 is a charge generation layer, and 4 is a surface protective layer. 5 is the conductive support 1
And an intermediate layer provided between the charge transporting layer 2.

Among the lubricants contained in the surface protective layer, the fluorine atom-containing resin or its fine particles include, for example, ethylene tetrafluoride resin, ethylene trifluoride chloride resin, hexafluoroethylene propylene resin, and fluorine fluoride. Examples include vinyl resin, vinylidene fluoride resin, fluorinated ethylene dichloride resin, copolymer resins thereof, and fine particles of each of the above resins.

As the polyolefin resin or the powder thereof, for example, polyethylene resin, polypropylene resin,
Examples include homopolymer resins such as polybutene resin and polyhexene resin, copolymer resin powders such as ethylene-propylene copolymer and ethylene-butene copolymer, and terpolymer resins such as ethylene-propylene-hexene copolymer.

As the fatty acid ester, C 8 -C 8
35 monohydric or polyhydric alcohol esters of fatty acids, which are solids derived from alcohols having 1 to 20 carbon atoms or powders thereof, for example, methyl stearate, ethylene glycol monostearate, glyceryl Tri (1,2-oxyl stearate), 1,2,4-butanetriol tristearate and the like can be mentioned.

The fatty acid metal salt includes 8 to 35 carbon atoms.
There are two saturated or unsaturated metal salts of fatty acids.

Examples of the metal constituting the fatty acid metal salt include lithium, sodium, potassium, rubidium, magnesium, calcium, zinc, strontium, cadmium, barium, mercury, aluminum, chromium, tin, titanium, zirconium, lead and manganese. , Iron, cobalt, nickel and the like, and may further include ammonium fatty acid salts. Examples of the fatty acid constituting the fatty acid metal salt include caprylic acid, pelargonic acid, caproic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid, arachidic acid, and behenic acid. , Lignoceric acid, cerotic acid and the like. Also, mixtures of these fatty acids, alcohols / esters and amides of these fatty acids are included in the present invention.

As waxes, for example, polyethylene glycol, methoxypolyethylene glycol and the like having a molecular weight of 60
There is carbowax which is a solid wax up to 00,
Cholesterol; techlorane or perchlorpentacyclodecane; polycaprolactone having a molecular weight of about 4000 or less; examples of fluorocarbon compounds include waxy short-chain telomers of tetrafluoroethylene and low molecular weight contaminating polytetrafluoroethylene powder Etc.

The various lubricants described above are preferably 0.01 to
It is dispersed and contained in the binder resin of the surface protective layer as a powder having a diameter of 3 μm, and its content is 1 to 50 with respect to the binder resin.
% By weight.

Each of the above lubricants is dispersed and contained in a surface protective layer forming a surface layer of a photoreceptor together with a fine particle reinforcing agent described later, and active species generated by corona discharge, development, transfer,
Increases durability against mechanical friction due to cleaning or the like.

As the reinforcing agent, at least one selected from acrylic resin fine particles, silicone resin fine particles, melamine resin fine particles, benzoguanamine resin fine particles, metal oxide fine particles, and inorganic compound whiskers is used.

As the acrylic resin fine particles, for example, thermosetting acrylic resin fine particles such as a melamine-modified acrylic resin and an epoxy-modified acrylic resin cured with a styrene-acryl resin, a methyl methacrylate resin or an isocyanate compound are used.

Examples of the silicone resin particles include silicone resins such as organopolysiloxanes, and other thermosetting resins such as acrylic-modified silicone resins, epoxy-modified silicone resins, alkyd-modified silicone resins, polyester-modified silicone resins, and urethane-modified silicone resins. Fine particles are used.

As the melamine resin fine particles, fine particles of a thermosetting resin obtained from melamine and formaldehyde are used.

As the benzoguanamine resin fine particles, fine particles of a thermosetting resin obtained from benzoguanamine and formaldehyde are used.

As the metal oxide fine particles, for example, Si
O ₂ , CrO ₂ , Al ₂ O ₃ , CeO ₂ , Fe ₂ O ₃ , TiO ₂ , ZnO, ZrO ₂ , Mg0
And the like.

As the whisker of the inorganic compound, for example, a whisker-like single crystal such as potassium titanate, calcium titanate, silicon carbide or silicon nitride is used.

The reinforcing agent is usually used in the form of fine particles having a diameter of 5 μm or less, preferably 0.05 to 3 μm, and is dispersed and contained in an amount of 10 to 200% by weight based on the binder resin of the surface protective layer. The content ratio of the reinforcing agent to the lubricant contained in the layer is 1 to 1000% by volume.

In order to improve the dispersibility of the reinforcing agent in the surface protective layer, the surface of the particles is preferably treated with a surfactant, a silane coupling agent or the like.

In the present invention, as described above, if necessary, an intermediate layer is formed on a conductive support, a charge transport layer and a charge generation layer are sequentially provided thereon, and a surface protective layer is further provided thereon. Forming the body.

As the charge generating substance contained in the charge generating layer, the following organic photoconductive materials that absorb visible light to generate free charges can be used.

(1) Azo pigments such as monoazo pigments, polyazo pigments, metal complex azo pigments, pyrazolone azo pigments, stilbene azo pigments and thiazole azo pigments (2) Perylene pigments such as perylene anhydride and perylene imide ( 3) Anthraquinone-based or polycyclic quinone-based pigments such as anthraquinone derivatives, anthantrone derivatives, dibenzpyrene quinone derivatives, pyranthrone derivatives, biolanthrone derivatives, and isobiolanthrone derivatives; and (4) indigoid-based pigments such as indigo derivatives and thioindigo derivatives. 5) Phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine (6) Carbonium pigments such as diphenylmethane pigment, triphenylmethane pigment, xanthene pigment and acridine pigment (7) Azine pigment, oxazine pigment (8) Methine pigments such as cyanine pigments and azomethine pigments (9) Quinoline pigments (10) Nitro pigments (11) Nitroso pigments (12) Benzoquinone and naphthoquinone pigments (13) Naphthalimide pigments (14) Perinone pigments such as bisbenzimidazole derivatives.

Among the pigments preferably used in the present invention, there are polycyclic quinone pigments represented by the following general formulas (1), (2) and (3).

[0049]

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[Wherein, in each of the above formulas, X is a halogen atom,
It represents a nitro group, a cyano group, an acyl group or a carboxyl group, n represents an integer of 0 to 4, and m represents an integer of 0 to 6. Specific examples of the polycyclic quinone pigment are described in, for example, JP-A-60-1
No. 72044, pages 24 to 26. Other usable charge generating substances include bisazo compounds represented by the following general formula (4).

[0051]

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[However, X ₁ and X _{2 in} this general formula (4)
Represents a hydrogen atom or a halogen atom.

A ₁ :

[0054]

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(X is a hydroxy group, or —N (R ² ) (R ³ ) or —NHSO ₂ —R ⁴ , wherein R ² and R ³ are each a hydrogen atom, a substituted or unsubstituted alkyl group, R ⁴ is a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group> Y is
Hydrogen atom, halogen atom, substituted or unsubstituted alkyl group,
An alkoxy group, a carboxyl group, a sulfo group, a substituted or unsubstituted carbamoyl group or a substituted or unsubstituted sulfamoyl group, provided that when m is 2 or more, they may be different groups. A) Z is a group of atoms necessary for forming a substituted or unsubstituted carbocyclic aromatic ring or a substituted or unsubstituted heterocyclic aromatic ring, and R ¹ is a hydrogen atom, a substituted or unsubstituted amino group. , A substituted or unsubstituted carbamoyl group, a carboxyl group or an ester group thereof, A ₂ is a substituted or unsubstituted aryl group, n is an integer of 1 or 2, and m is an integer of 0 to 4. Specific examples of the bisazo compound of the general formula (4) are described, for example, in JP-A-1-200361, pages 3 to 10.

Further, as another charge generating substance, a bisazo compound represented by the following general formula (5) can also be used.

[0057]

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(However, in this general formula, A ₃ is

[0059]

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Z: an atomic group necessary for forming a substituted or unsubstituted aromatic carbocyclic ring or a substituted or unsubstituted aromatic heterocyclic ring; Y: a hydrogen atom, a hydroxyl group, a carboxyl group or an ester group thereof , A sulfo group, a substituted or unsubstituted carbamoyl group, or a substituted or unsubstituted sulfamoyl group, R ⁵ : a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted carbamoyl group , A carboxyl group or an ester group thereof, or a cyano group, Ar ³ : a substituted or unsubstituted aryl group, R ⁶ : a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group Represents Specific examples of the bisazo compound represented by the general formula (5) include Japanese Patent Application Laid-Open No.
It is described on page 4.

The above-mentioned charge generating substance is dispersed and contained in a binder resin in the form of fine particles having a diameter of 0.1 to 1 μm, and a layer is formed.

As the binder resin contained in the charge generation layer, all resins for electrophotography are useful, for example, polyethylene, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, vinyl acetate resin. Butyral resin, vinyl formal resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, addition polymerization type resin such as melamine resin, polyaddition type resin, polycondensation type resin, and these Copolymer resin containing two or more of the repeating units of the resin, for example, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-
In addition to insulating resins such as vinyl acetate-maleic anhydride copolymer resin, polymer organic semiconductors such as poly-N-vinyl carbazole can be mentioned.

The charge transport materials contained in the charge transport include oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl derivatives Compounds, hydrazine compounds, pyrazoline derivatives, oxazolone derivatives, benzothiazole derivatives,
Benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives,
Examples include aminostilbene derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene, and the like.

Specific examples include styryl compounds of the following general formula (6) or (7).

[0065]

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In the above formula, R ⁷ and R ⁸ represent the following two substituted or unsubstituted groups; an alkyl group and an aryl group, wherein the substituent is an alkyl group, an alkoxy group, a substituted amino group, a hydroxyl group, a halogen atom, Atoms and aryl groups.

Ar ⁴ and Ar ⁵ each represent a substituted or unsubstituted aryl group. Examples of the substituent include an alkyl group, an alkoxy group, a substituted amino group, a hydroxyl group, a halogen atom, and an aryl group.

R ⁹ and R ¹⁰ represent a substituted or unsubstituted aryl group or a hydrogen atom, and examples of the substituent include an alkyl group, an alkoxy group, a substituted amino group, a hydroxyl group, a halogen atom, and an aryl group.

[0069]

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In the above formula, R ¹¹ is a substituted or unsubstituted aryl group, R ¹² is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, an amino group, a substituted amino group, a hydroxyl group, R ¹³ Is a substituted or unsubstituted aryl group,
Represents an unsubstituted heterocyclic group.

The hydrazone compound of the following general formula (8), (9), (10) or (11) can also be used as a carrier transporting substance.

[0072]

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In the formula, R ¹⁴ and R ¹⁵ each represent a hydrogen atom or a halogen atom, R ¹⁶ and R ¹⁷ each represent a substituted or unsubstituted aryl group, and Ar ⁶ represents a substituted or unsubstituted arylene group.

[0074]

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In the formula, R ¹⁸ is a methyl group, an ethyl group, a 2-hydroxyethyl group or a 2-chloroethyl group, R ¹⁹ is a methyl group, an ethyl group, a benzyl group or a phenyl group, R ²⁰ is a methyl group, an ethyl group, Indicates a benzyl group or a phenyl group.

[0076]

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In the formula, R ²¹ is a substituted or unsubstituted naphthyl group;
R ²² is a substituted or unsubstituted three group; an alkyl group, an aralkyl group or an aryl group, R ²³ is a hydrogen atom, an alkyl group or an alkoxy group, R ²⁴ and R ²⁵ are a substituted or unsubstituted three group Group: the same or different groups selected from an alkyl group, an aralkyl group and an aryl group.

[0078]

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In the formula, R ²⁶ is a substituted or unsubstituted aryl group or substituted, unsubstituted heterocyclic group, and R ²⁷ is a hydrogen atom,
The following two unsubstituted groups; an alkyl group, an aryl group, and Q are a hydrogen atom, a halogen atom, an alkyl group, a substituted amino group,
Represents an alkoxy group or a cyano group, and m represents an integer of 0 or 1.

Further, as the charge transport material, the following general formula (1)
The pyrazoline compound of 2) can also be used.

[0081]

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In the formula, n represents 0 or 1, R ²⁸ , R ²⁹ and R ³⁰ are a substituted or unsubstituted aryl group, R ³¹ and R ³² are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, Or a substituted or unsubstituted aryl group or aralkyl group. However,
R ³¹ and R ³² are not both hydrogen atoms, and n is 0
In the case, R ³¹ is not a hydrogen atom.

Further, an amine derivative represented by the following general formula (13) can also be used as a charge transporting substance.

General formula (13) Ar ⁹ -N (Ar ⁷ ) (Ar ⁸ ) wherein Ar ⁷ and Ar ⁸ represent a substituted or unsubstituted phenyl group;
As the substituent, a halogen atom, an alkyl group, a nitro group,
An alkoxy group is used.

Ar ⁹ represents a substituted or unsubstituted phenyl group, a naphthyl group, an anthryl group, a fluorenyl group or a heterocyclic group, wherein the substituent is an alkyl group, an alkoxy group, a halogen atom, a hydroxyl group, an aryloxy group or an aryl group. , An amino group, a nitro group, a piperidino group, a morpholino group, a naphthyl group, an anthryl group and a substituted amino group. However,
As a substituent of the substituted amino group, an acyl group, an alkyl group, an aryl group, or an aralkyl group is used.

Specific examples of the charge transporting compounds represented by formulas (6) to (13) are described in JP-A-60-172044.

As the binder resin contained in the charge transport layer, all resins for electrophotography are useful, for example, polyethylene, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, vinyl acetate resin. Butyral resin, vinyl formal resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, addition polymerization type resin such as melamine resin, polyaddition type resin, polycondensation type resin, and these Copolymer resin containing two or more of the repeating units of the resin, for example, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-
In addition to insulating resins such as vinyl acetate-maleic anhydride copolymer resin, polymer organic semiconductors such as poly-N-vinyl carbazole can be mentioned.

Hereinafter, the layer structure of the photoreceptor of the present invention will be described more specifically with reference to FIG.

In the drawing, the conductive support 1 may be formed of any of conductive and insulating materials. Examples of the conductive material include metals such as stainless steel, aluminum, chromium, molybdenum, iridium, tellurium, titanium, platinum, and palladium, and alloys thereof. Examples of the insulating material include films or sheets of synthetic resin such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, and polyamide, glass, ceramic, and paper. When an insulating material is used, it is preferable that its surface is subjected to a conductive treatment. In particular,
For example, in the case of glass, conductive treatment is performed with indium oxide, tin oxide, or the like, and in the case of a synthetic resin film such as a polyester film, aluminum, silver, lead, nickel,
Conduction treatment of metals such as gold, chromium, molybdenum, iridium, niobium, tantalum, vanadium, titanium, platinum by vacuum evaporation, electron beam evaporation, sputtering, etc., or by conducting lamination with the above metals .

On the conductive support 1, if necessary, an intermediate layer 5 is provided for the purpose of preventing charge injection from the support 1 and improving the adhesion between the support 1 and the charge transport layer 2. Is provided. That is, other than the binder resin used for the charge transport layer, polyvinyl alcohol, ethyl cellulose, carboxymethyl cellulose, casein, organic polymer compounds such as starch are applied by a method such as dip coating and spray coating,
The intermediate layer 5 having a thickness of 0.01 to 2 μm is formed by a method such as vacuum deposition and sputtering of aluminum oxide or the like. Next, on the intermediate layer 5, 20 to 200 parts by weight, preferably 30 to 100 parts by weight of the charge transporting substance is added to 100 parts by weight of the binder resin.
The charge transport layer 2 having a thickness of 5 to 50 [mu] m is formed by being dissolved in parts by weight. Next, on the charge transport layer 2, a charge generation layer 3 containing 5 to 1000 parts by weight, preferably 20 to 500 parts by weight of the charge generation substance dispersed in 100 parts by weight of the binder resin is formed to a thickness of 0.05 to 10 μm. 0.3 on the charge generation layer 3
The photoreceptor of the present invention is obtained by laminating the surface protective layer 4 having a thickness of about 5 μm. In the charge generation layer, if necessary, a charge transport material,
An additive such as an antioxidant may be contained.

The antioxidant contained in the surface protective layer includes, for example, compounds of the following groups (I) to (V).

Group (I): hindered phenols dibutylhydroxytoluene, 2,2'-methylenebis (6-
t-butyl-4-methylphenol), 4,4'-butylidenebis (6-t-butyl-3-methylphenol), 4,4'-thiobis (6-t-butyl-3-methylphenol), 2, 2'-butylidenebis (6-t-butyl-4-methylphenol), α-tocophenol, β-tocophenol, 2,2,4-trimethyl-6-
Hydroxy-7-t-butylchroman, pentaerythyltetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,2'-thiodiethylenebis [3-
(3,5-di-t-butyl-4-hydroxyphenyl) propionate], 1,6-hexanediol bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], butylhydroxy Anisole, dibutylhydroxyanisole and the like. Group (II): paraphenylenediamines N-phenyl-N'-isopropyl-p-phenylenediamine,
N, N'-di-sec-butyl-p-phenylenediamine, N'-phenyl-N-sec-butyl-p-phenylenediamine, N, N'-diisopropyl-p-phenylenediamine, N, N'-dimethyl -N,
N'-di-t-butyl-p-phenylenediamine and the like.

Group (III): hydroquinones 2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl
-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- (2-octadecenyl) -5-methylhydroquinone and the like.

Group (IV): organic sulfur compounds dilauryl-3,3'-thiodipropionate, distearyl-3-3'-thiodipropionate, ditetradecyl-3,
3'-thiodipropionate and the like.

Group (V): Organophosphorus compounds Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine and the like.

These compounds are known as antioxidants for rubber, plastics, oils and the like, and commercially available products can be easily obtained.

The hindered phenols of the group (I), which have particularly excellent antioxidant effects among the antioxidants of the groups (I) to (V), are preferably used in the present invention.

When the amount of the lubricant in the surface protective layer of the photoreceptor of the present invention is less than 1 part by weight per 100 parts by weight of the binder resin, no lubricating effect can be obtained, resulting in poor cleaning or poor mechanical strength. If the amount is lower than 50 parts by weight, the film becomes brittle and the mechanical strength is reduced.

Further, the amount of the reinforcing agent is set to
If the amount is less than 10 parts by weight, the effect of improving the film strength cannot be obtained, and if it exceeds 200 parts by weight, the film becomes brittle and the mechanical strength decreases.

Hereinafter, the present invention will be described specifically with reference to Examples, but the embodiments of the present invention are not limited thereto.

[0101]

【Example】

Example 1 An aluminum drum having an outer diameter of 80 mm and a length of 355.5 mm was prepared, a charge transport layer having a thickness of 20 μm was provided by a dipping method using the following coating solution, and dried at 90 ° C. for 30 minutes.

<Coating Solution for Forming Charge Transport Layer> 1,2-Dichloroethane 1000 ml Polycarbonate (Teijin Chemical Co., Ltd. TS-2020) 200 g Polyester (Toyobo Co., Ltd. Byron 200) 5 g Exemplary compound [I] 150 g Antioxidant ( Sumitomo Chemical Co., Ltd. Sumilizer BHT) 5 g Silicone oil (Shin-Etsu Chemical Co., Ltd. KF-54) 0.1 g Next, a 2 μm-thick charge generation layer was formed on the charge transport layer by a circular slide hopper method using the following coating solution. And 90
Dry at 30 ° C. for 30 minutes.

<Coating solution for forming charge generation layer> 1,2 Dichloroethane 1000 ml Polycarbonate (Tesjin Chemical Co., Ltd. TS-2050) 10 g Exemplified compound [I] 5 g Exemplified compound [II] 30 g Antioxidant (Sumitomo Chemical Co., Ltd.) Sumilyzer BHT) 0.5 g Silicone oil (Shin-Etsu Chemical Co., Ltd. KF-54) 0.2 g Subsequently, a surface protection layer having a thickness of 2 μm was provided on the charge generation layer by a circular slide hopper method using the following coating solution, and then heated at 120 ° C. Dried for 30 minutes.

<Coating Liquid for Forming Surface Protective Layer> Silicone resin (Shin-Etsu Chemical Co., Ltd. KP-85, solid content concentration 20%) 1000 ml Polyvinyl butyral resin (Sekisui Chemical Co., Ltd. Eslec BX-1) 5 g Silicone resin fine particles (Toshiba Silicone Tospearl 120) 50 g PTFE fine particles (Daikin Industries, Ltd. Lubron L-2) 20 g Antioxidant (Sumitomo Chemical Co., Ltd. Sumilizer BHT) 5 g The results are shown in Table 1.

The photoreceptor thus obtained was mounted on a modified U-Bix3035 copier manufactured by Konica Corporation, and a 10,000-copies actual copying test was performed to evaluate the change in the surface potential of the photoreceptor and the copy image. As Comparative Example 1, Example 1
A photoreceptor having no surface protective layer formed thereon was prepared and evaluated in the same manner. The results are shown in Table 1.

[0106]

[Table 1]

Examples 2 to 13 The composition of the surface protective layer of Example 1 was replaced with A in place of silicone resin and B in place of silicone resin fine particles as shown in the following table.
A photoconductor was prepared in the same manner as in Example 1 except that C was used instead of the PTFE fine particles, and the same evaluation was performed.

Comparative Example 2 A photoconductor was prepared in the same manner as in Example 1, except that no silicone resin fine particles were added.

Comparative Example 3 A photoconductor was prepared and evaluated in the same manner as in Example 1 except that PTFE fine particles were not added.

[0110]

[Table 2]

[0111]

[Table 3]

The structural formulas of the exemplified compounds [I] and [II] used in the examples are shown below.

[0113]

Embedded image

As shown in Table 3, in the examples of the present invention, there was little decrease in sensitivity due to wear and no image defects occurred.

[0115]

The photoreceptor of the present invention is a positively charged photoreceptor having a charge transport layer as a lower layer and a charge generation layer and an upper layer. Specific thermosetting resin, moisture having a diameter of 0.01 to 3 μm
Fluorine atom-containing fine particles as a lubricant, a reinforcing agent, by the inclusion of及beauty oxidation inhibitor, it is possible to impart high durability characteristics strongly photoelectrically deterioration and mechanical wear on the photoreceptor, therefore Effects such as stably obtaining high image quality can be obtained in long-term use of the photoreceptor.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a layer configuration of a photoconductor of the present invention.

FIG. 2 is a cross-sectional view illustrating a layer configuration of a photoconductor of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conductive support 2 charge transport layer 3 charge generation layer 4 surface protective layer 5 intermediate layer

Continuation of the front page (56) References JP-A-3-13961 (JP, A) JP-A-3-211561 (JP, A) JP-A-2-149855 (JP, A) JP-A-63-18354 (JP) JP-A-57-73744 (JP, A) JP-A-4-328570 (JP, A) JP-A-63-291063 (JP, A) JP-A-56-99347 (JP, A) JP-A-57-165848 (JP, A) JP-A-54-35732 (JP, A) JP-A-56-25749 (JP, A) JP-A-62-192754 (JP, A) A) JP-A-4-221964 (JP, A) JP-A-4-240656 (JP, A) JP-A-4-240657 (JP, A) JP-A-4-241359 (JP, A) JP-A-4 -336542 (JP, A) JP-A-4-346358 (JP, A) JP-A-4-358158 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 5/147

Claims (2)

(57) [Claims] 1. An electrophotographic photoreceptor comprising a charge transport layer, a charge generation layer and a surface protection layer laminated in this order on a conductive support, wherein a thermosetting resin is provided in the surface protection layer;
A fluorine atom-containing fine particles as a lubricant having a 0.01~3μm diameter, silicone resin particles, benzoguanamine resin particles, metal oxide powder, inorganic whiskers, particulate acrylic resin, at least selected from melamine resin particles one reinforcing agent And an antioxidant. 2. The thermosetting resin is a silicone resin, an acrylic resin, a phosphazene resin, a polyester resin,
2. The electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor is any one of melamine resin and phenol resin or a mixture thereof.