JPH10288848A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to provide a photoreceptor having sufficient mechanical strength without degrading the opto-electric characteristics and image grade of the photoreceptor and high durability even under a strong external stress by incorporating a charge transferable low polymer compd. into a charge transfer layer. SOLUTION: The surface of a conductive base 3 is provided with the charge generating layer 1, the charge transfer layer 2 consisting of the charge transferable high polymer compd. and a protective layer 5 and the charge transferable low polymer compd. is incorporated into the charge transfer layer 2. The charge transferable low polymer compd. is the benzene based compd. expressed by formula I and/or the triphenyl amine based component expressed by formula II. In the formula I, R1 and R1 ' may be the same or different and denote hydrogen atoms, alkyl groups, etc.; R2 , R2 ', R3 and R3 ' may be the same or different and denote hydrogen atoms, substrate amino groups, etc.; k, k', m and m' respective denote an integer of 1 or 2. In the formula II, R4 denotes a hydrogen atom or methyl group; (n)denotes an integer of 1 or 2; Ar1 and Ar2 denotes a substd. or unsubstd. aryl group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic photoreceptor having a charge generation layer, a charge transport layer and a surface protective layer.

[0002]

2. Description of the Related Art In recent years, electrophotographic technology has been widely used in the fields of copiers, laser beam printers, facsimile machines, and the like because high speed and high printing quality can be obtained. As the electrophotographic photoreceptor used in these electrophotographic techniques, those using inorganic photoconductive materials such as selenium, selenium-tellurium alloy, selenium-arsenic alloy, and cadmium sulfide have been widely known.

On the other hand, research on electrophotographic photoreceptors using organic photoconductive materials which are inexpensive and excellent in manufacturability and disposal properties as compared with electrophotographic photoreceptors using these inorganic photoconductive materials has been active. Among them, a function-separated organic layered photoconductor in which a charge generation layer that generates charges by exposure and a charge transport layer that transports charges are laminated has electrophotographic characteristics such as sensitivity, chargeability, and its repetition stability. Because of its superiority, various proposals have been made and put to practical use.

On the other hand, at present, a single-layer type organic photoreceptor has advantages in terms of manufacturability, production cost, and a system of positive chargeability (reduction of ozone generation, uniform chargeability), but has poor electrical performance. There is a problem that it is inferior to a stacked photoreceptor, and there is still room for research and development.

On the other hand, the durability required for the electrophotographic photosensitive member is becoming severer year by year, and the wear and damage of the surface layer due to repeated use, particularly the surface layer which is remarkably increased when a contact charging system is adopted. With respect to problems such as abrasion and scratches and oxidative deterioration of a surface layer due to oxidizing gas such as ozone generated from a corona charger, technical development required for improving durability has been continued. To solve these problems of the surface layer, there has been proposed a method of forming a surface protective layer mainly containing a cross-linkable curable resin such as an organic polysiloxane on the charge transport layer (Japanese Patent Application Laid-Open No. 54-148737). .

However, the above-mentioned surface protective layer is laminated and applied on a conventionally used charge transporting layer in which a low molecular weight compound having a charge transporting property is dispersed in a binder resin such as a polycarbonate resin to form a photosensitive layer. When formed, the charge transporting low molecular weight compound in the charge transport layer is eluted into the surface protective layer due to the solvent of the coating solution for the surface protective layer, and the mechanical strength is significantly impaired.

In recent years, studies have been made in view of these problems. When a surface protective layer is laminated on a charge transporting layer using a charge transporting high molecular weight compound, the charge transporting low molecular weight compound is transferred from the charge transporting layer. However, there is a problem that the solvent in the coating solution for the surface protective layer relaxes the residual stress in the charge transport layer and cracks or the like occur in the surface protective layer.

[0008]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems, and has a sufficient mechanical strength without deteriorating the photoelectric characteristics and image quality of an electrophotographic photoreceptor. An object of the present invention is to provide an electrophotographic photosensitive member having a surface protective layer exhibiting high durability even under long-term use under stress.

[0009]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have intensively studied a charge transporting layer using a charge transporting polymer compound, and as a result, have found that a specific charge transporting property is low. By adding a molecular compound, the charge transporting low molecular weight compound does not elute from the charge transport layer even when the surface protective layer is laminated, no crack occurs in the surface protective layer, and the photoelectric characteristics of the electrophotographic photoreceptor are reduced. Further, they have found that they have sufficient mechanical strength without deteriorating the image quality and exhibit high durability even in long-term use under strong external stress, and have completed the present invention. That is, the configuration of the present invention is as follows.

(1) In an electrophotographic photosensitive member having a charge generating layer, a charge transporting layer comprising a charge transporting polymer compound and a surface protective layer provided on a conductive support, the charge transporting layer has a low charge transporting property. A photoconductor for electrophotography, comprising a molecular compound.

(2) The low-molecular compound having a charge transporting property is a benzidine compound represented by the following general formula (I) and / or a triphenylamine compound represented by the following general formula (II). The electrophotographic photosensitive member according to claim 1, wherein

[0012]

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(In the formula, R ₁ and R ₁ ′ may be the same or different and each represents a hydrogen atom, an alkyl group, preferably an alkyl group having 1 to 5 carbon atoms, an alkoxy group, and preferably 1 carbon atom. R ₂ , R ₂ ′, R ₃ and R ₃ ′ may be the same or different, and represent a hydrogen atom, an alkyl group, preferably having 1 to 5 carbon atoms. An alkyl group, an alkoxy group, preferably an alkoxy group having 1 to 5 carbon atoms, a halogen atom, or a substituted amino group, preferably an amino group substituted with an alkyl group having 1 to 3 carbon atoms. , And
k, k ', m and m' each represent an integer of 1 or 2. )

[0014]

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(Wherein, R ₄ represents a hydrogen atom or a methyl group. N represents an integer of 1 or 2. Ar ₁ and Ar ₂
Represents a substituted or unsubstituted aryl group, and Ar ₁ and Ar
_As a substituent of ₂ , a hydrogen atom, a halogen atom, an alkyl group, preferably an alkyl group having 1 to 5 carbon atoms, an alkoxy group, preferably an alkoxy group having 1 to 5 carbon atoms, or a substituted amino Group, preferably having 1 to 1 carbon atoms
It has an amino group substituted with an alkyl group in the range of 3. )

(3) The electrophotographic photoreceptor according to the above (1) or (2), wherein the charge transporting polymer compound is represented by the following general formulas (III) to (VII): .

[0017]

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(R ₅ and R ₆ are each independently a hydrogen atom,
Alkyl group, preferably an alkyl group having 1 to 5 carbon atoms, an alkoxy group, preferably an alkoxy group having 1 to 5 carbon atoms, a substituted amino group, preferably 1 carbon atom;
Represents an amino group, a halogen atom, an unsubstituted aryl group, or a substituted aryl group, preferably an aryl group substituted with an alkyl group having 1 to 3 carbon atoms, X is an unsubstituted divalent aryl group;
Or a substituted divalent aryl group, preferably having 1 carbon atom
Represents a divalent aryl group substituted with an alkyl group in the range from 1 to 3. T is an aliphatic divalent hydrocarbon group which may be branched, preferably an aliphatic moiety having 1 to 15 carbon atoms which may be branched, more preferably aliphatic. Represents a divalent hydrocarbon group which may have 1 to 10 carbon atoms. p and q are 0 or 1
Means an integer. )

[0019]

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(R ₇ and R ₈ are each independently a hydrogen atom,
Alkyl group, preferably an alkyl group having 1 to 5 carbon atoms, an alkoxy group, preferably an alkoxy group having 1 to 5 carbon atoms, a substituted amino group, preferably 1 carbon atom;
An amino group, a halogen atom, an unsubstituted aryl group, or a substituted aryl group substituted with an alkyl group of
Preferably, it represents an aryl group substituted with an alkyl group having 1 to 3 carbon atoms. X represents an unsubstituted divalent aryl group or a substituted divalent aryl group, preferably a divalent aryl group substituted with an alkyl group having 1 to 3 carbon atoms. T is an aliphatic divalent hydrocarbon group which may be branched, preferably an aliphatic moiety having 1 to 15 carbon atoms.
Represents a divalent hydrocarbon group which may be branched, more preferably a divalent hydrocarbon group having 1 to 10 carbon atoms in an aliphatic portion which may be branched. r and s each represent an integer of 0 or 1. )

[0021]

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(Wherein A represents the above general formula (III) or (IV)
Wherein Y is a divalent hydrocarbon group, preferably a divalent alkylene group, an arylene group, an alicyclic hydrocarbon group, or —R—O—R— (where R is a divalent hydrocarbon group) Alkylene group). t represents an integer in the range of 1 to 5, and u represents 5
It means an integer in the range of -5000. )

[0023]

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(Wherein A represents the above general formula (III) or (IV)
Wherein Y, Y ′ and Y ″ are divalent hydrocarbon groups, preferably divalent alkylene groups, arylene groups, alicyclic hydrocarbon groups, or —R—O—R— (R is 2
Valent alkylene group). v means an integer in the range of 1 to 5, w means an integer in the range of 5 to 5000. )

[0025]

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(Wherein A represents the above general formula (III) or (IV)
Wherein Y, Y ′ and Y ″ are divalent hydrocarbon groups, preferably divalent alkylene groups, arylene groups, alicyclic hydrocarbon groups, or —R—O—R— (R is 2
Valent alkylene group). x means an integer in the range of 1 to 5, y means an integer in the range of 5 to 5000, z means an integer in the range of 1 to 3500, and y + z = 5 to 50
It is an integer of 00 and satisfies 1> y / (y + z) ≧ 0.3. )

(4) The above (1), wherein the surface protective layer comprises conductive metal oxide particles and a thermosetting resin.
An electrophotographic photoreceptor according to any one of claims 1 to 3.

(5) As the thermosetting resin, at least one resin selected from the group consisting of polyamide resin, polyurethane resin, polyester resin, epoxy resin, acrylic resin, silicone resin, and polyacrylamide resin is used. The electrophotographic photosensitive member according to the above (4), which is characterized in that:

(6) The surface protective layer comprises a charge transporting material having a reactive functional group and a compound having a reactive functional group for the charge transporting material, and reacts with each other by heating to form a cross-linked network. The electrophotographic photoreceptor according to any one of the above (1) to (4), wherein

(7) The combination of the reactive functional groups is selected from the group consisting of a hydroxy group and an isocyanate group, an amino group and an epoxy group, and an amino group and an isocyanate group, and crosslinks in a network. The electrophotographic photosensitive member according to the above (6), which is characterized in that:

(8) As the compound into which the hydroxy group has been introduced, a dihydroxy compound having a triphenylamine skeleton;
The electrophotographic photoreceptor according to (7), wherein a dihydroxy compound having a benzidine skeleton or a bisphenol compound having triphenylamine introduced into a side chain is selected.

[0032]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor having a charge generating layer, a charge transporting layer comprising a charge transporting polymer compound and a surface protective layer provided on a conductive support. A charge transporting low molecular compound is contained, and if necessary, a surface protective layer is formed of a conductive metal oxide particle, and a charge transporting material having a thermosetting resin or a reactive functional group and a reactive functional group for the material. By constructing a compound having a group in a cross-linked form in a network form, the mechanical strength can be improved without deteriorating the photoelectric characteristics and image quality of the photoreceptor, and in long-term use under external stress. Also,
It has become possible to provide an electrophotographic photoreceptor having high durability.

The charge transporting layer of the present invention is obtained by adding a charge transporting low molecular weight compound in addition to a charge transporting high molecular weight compound and dispersing the molecule. The charge transporting low molecular weight compound is represented by the above general formula (I) And / or a triphenylamine compound represented by the general formula (II), wherein the charge-transporting polymer compound is a compound represented by the general formula (III) to
(VII).

X in the above general formulas (III) and (IV)
Can be selected from the following structural formulas (X-1) to (X-7).

[0035]

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(In the structural formulas (X-1) to (X-7), R ₉ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an unsubstituted phenyl group,
Represents a substituted phenyl group, preferably a phenyl group substituted with an alkyl group, or a substituted or unsubstituted aralkyl group, wherein R _{10 to} R ₁₆ are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, An alkoxy group, an unsubstituted phenyl group, a substituted phenyl group, preferably a phenyl group substituted with an alkyl group, a substituted or unsubstituted aralkyl group,
Alternatively, it represents a halogen atom. In the structural formula (X-7), A
r ₃ is the same as that represented by the above structural formula (X-3), and V is selected from the following structural formulas (V-1) to (V-10);
a represents an integer of 0 or 1, b represents an integer of 1 to 10, and c represents an integer of 1 to 4. )

[0037]

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Among the above general formulas (III) and (IV), a polymer having a biphenyl structure wherein X is represented by the following structural formula (X-8) or (X-9) has high mobility and practicality Is high.

[0039]

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T in the general formulas (III) and (IV) is a divalent aliphatic hydrocarbon group which may be branched and has the following structural formulas (T-1) to (T-33). ) Can be selected. The arylamine skeleton may be bonded to either side. For example, a tetraarylbenzidine skeleton is bonded to the right side of the structure T-2 when T-2R is written, and to the left side of the structure T-2 when T-2L is written. It indicates that

[0041]

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[0042]

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In the general formulas (V) to (VII), Y, Y 'and Y "can be selected from the substituents represented by the following structural formulas (Y-1) to (Y-7). it can.

[0044]

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(R _{17 to} R ₂₀ are a hydrogen atom, a carbon number of 1 to 4
Represents an alkyl group, an alkoxy group having 1 to 4 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted aralkyl group, or a halogen atom, and d and e represent 1 to 10
F, h, i, j mean an integer in the range of 0 to 2, and g, k mean an integer in the range of 0 to 2. V is represented by the above substituents (V-1) to (V-10). )

Specific examples of the charge-transporting low molecular weight compound are shown in Tables 1 to 3 as specific examples of the benzidine compound represented by the general formula (I), and specific examples of the triphenylamine compound represented by the general formula (II). Examples are shown in Tables 4-6.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

[Table 3]

[0050]

[Table 4]

[0051]

[Table 5]

[0052]

[Table 6]

For the charge transporting polymer compound, specific examples of the structural formula represented by the general formula (III) are shown in Tables 7 to 7.
9, specific examples of the structural formula represented by the general formula (IV) are shown in Tables 10 to 12, specific examples of the structural formula represented by the general formula (V) are shown in Tables 13 to 14, Table 15 shows specific examples of the structural formula represented by the general formula (VI), and Table 16 shows specific examples of the charge transporting polymer compound represented by the general formula (VII). The partial structure in Tables 13 to 16 means A in the general formulas (V) to (VII). Further, the compounds described in the structures in the above table are the compounds (III) described in Tables 7 to 12.
And (IV). The ratio means a ratio when two of the above compounds are used.

[0054]

[Table 7]

[0055]

[Table 8]

[0056]

[Table 9]

[0057]

[Table 10]

[0058]

[Table 11]

[0059]

[Table 12]

[0060]

[Table 13]

[0061]

[Table 14]

[0062]

[Table 15]

[0063]

[Table 16]

In the charge transporting layer of the electrophotographic photosensitive member of the present invention, the composition ratio of the charge transporting high molecular compound to the charge transporting low molecular weight compound is 0.1 to 100 parts by weight of the charge transporting high molecular compound. A suitable range is from 10 to 10 parts by weight,
A range of 5 parts by weight is particularly preferred. If the amount is less than 0.1 part by weight, the effect of the addition is reduced and cracks are likely to occur. If the amount exceeds 10 parts by weight, the charge transporting low molecular weight compound is eluted into the surface protective layer, and The mechanical strength decreases.

The preferred weight average molecular weight (Mw) of the charge transporting polymer compound in the present invention is from 5,000 to 75.
0000, more preferably 50,000 to 500,0.
00 range.

Further, an antioxidant may be added to the charge transport layer. Since the charge transport layer is not the outermost layer, it does not directly touch the oxidizing gas, but this oxidizing gas may penetrate the surface protective layer and penetrate to the charge transport layer,
The above antioxidant is added to prevent this. As the antioxidant, hindered phenol-based or hindered amine-based antioxidants are preferable, and organic sulfur-based antioxidants, phosphite-based antioxidants, dithiocarbamate-based antioxidants, thiourea-based antioxidants, and benzimidazole-based antioxidants A well-known antioxidant such as may be used.

Solvents for the coating solution for the charge transport layer include aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene, ketones such as acetone and 2-butanone, and halogenated compounds such as methylene chloride, chloroform and ethylene chloride. Common organic solvents such as aliphatic hydrocarbons, cyclic or linear ethers such as tetrahydrofuran, ethyl ether and dioxane can be used alone or in combination of two or more.

As a method for applying the charge transporting layer, conventional methods such as a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method and a curtain coating method can be used. . The thickness of the charge transport layer is 5 to 50 μm, preferably 10 to 40 μm.
m.

The surface protective layer of the present invention is formed by dispersing a conductive material in a suitable binder resin. Examples of the conductive material include metallocene compounds such as N, N′-dimethylferrocene and N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1′-biphenyl] -4,4. '
-Aromatic amine compounds such as diamine, antimony oxide,
Metal oxides such as tin oxide, titanium oxide, indium oxide, and tin oxide-antimony oxide can be given.

As the binder resin used for the surface protective layer, polyamide resin, polyurethane resin, polyester resin,
Known resins such as an epoxy resin, a polyketone resin, a polycarbonate resin, a polyvinyl ketone resin, a polystyrene resin, and a polyacrylamide resin can be used.

Among the above combinations of the conductive material and the binder resin, conductive metal oxide particles such as tin oxide, antimony oxide, and tin oxide-antimony oxide are mixed in a thermosetting resin such as a polyurethane resin or an acrylic resin. The surface protective layer in which particles are dispersed is particularly excellent in mechanical properties and electrical properties.

Further, the surface protective layer of the present invention comprises a charge transporting material having a reactive functional group and a compound having a functional group having a reactivity with them. A combination can be formulated.

The combinations of the reactive functional groups include a hydroxy group and an isocyanate group, an amino group and an epoxy group,
Examples include an amino group and an isocyanate group. Among them, a compound having a hydroxy group and a compound having an isocyanate group are preferably reacted with each other to form a film by cross-linking in a network.

Among them, the compound having a hydroxy group is a compound having a hydroxy group introduced into a charge transporting material, a compound having a hydroxy group directly introduced into a conventionally used charge transporting material, or a compound having an appropriate substitution. Those in which a hydroxy group is introduced indirectly across a group can be used.

The number of substitution of the hydroxy group of the charge transporting material may be one or more. In order to form a network structure by crosslinking, a charge transporting material having two or more hydroxy groups is contained. Alternatively, it is necessary to simultaneously include at least one or more binders having two or more hydroxy groups.

Specific examples of the charge transporting material having a hydroxy group introduced therein include a dihydroxy compound having a triphenylamine skeleton, a dihydroxy compound having a benzidine skeleton, and a bisphenol compound having triphenylamine introduced into a side chain.

As the binder which may be used simultaneously with the charge transporting material having a hydroxy group, monomers, oligomers and polymers having a plurality of hydroxy groups can be used. Examples of the monomer / oligomer include glycols such as ethylene glycol and propylene glycol, and polyethylene glycols. Further, various polymers having a hydroxy group such as acrylic polyol and polyester polyol can also be used.

As the compound which forms a network structure by binding to the above-mentioned compound having a hydroxy group by an addition reaction, a polyisocyanate compound having a plurality of isocyanate groups, preferably three or more isocyanate groups is used. Can be.

Examples of the polyisocyanate include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate, tolidine diisocyanate, 1,6-hexamethylene diisocyanate, xylene diisocyanate, lysine isocyanate, and tetramethyl isocyanate. Xylene diisocyanate, 1,3,6-hexamethylene triisocyanate, lysine ester triisocyanate, 1,
6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanatomethyloctane,
Examples thereof include polyisocyanates composed of monomers such as triphenylmethane triisocyanate and tris (isocyanatephenyl) thiophosphate.

Among them, from the viewpoints of ease of handling, film formability of a finally obtained crosslinked film, crack resistance, and the like, it is preferable to use a modified product such as a derivative or a prepolymer obtained from a polyisocyanate monomer. Is more desirable. As these examples, particularly preferred are urethane-modified products obtained by modifying a polyol with an excess of an isocyanate compound, buret-modified products obtained by modifying a compound having a urea bond with an isocyanate compound, and allophanate-modified products obtained by adding an isocyanate to a urethane group. Also, modified isocyanurate, carbodiimide and the like are used.

Blocked isocyanates which are included in the above modified polyisocyanate and reacted with a blocking agent for temporarily masking the activity of isocyanate groups can also be preferably used. In order to form the surface protective layer of the present invention, a charge transporting material having a hydroxy group and a polyisocyanate compound, and if necessary, a binder or a solvent having a hydroxy group are added and mixed, and the mixture is formed on the photosensitive layer. After coating, cross-linking polymerization is performed to form a film.

These mixing ratios are preferably adjusted so that the number of all hydroxy groups and the number of all isocyanate groups are substantially equal. In particular, if an excessive hydroxyl group remains, it increases the hydrophilicity of the surface of the surface protective layer and causes deterioration of image characteristics under high temperature and high humidity. Therefore, it is necessary to pay attention to reaction conditions and the like.

In order to carry out the cross-linking polymerization of the surface protective layer of the present invention, the surface protective layer material may be coated on the photosensitive layer and then heated. In the addition reaction between the hydroxy group and the isocyanate group, the reactivity between the above compounds is good. Therefore, generally, a catalyst or the like is not required, and only heating is required. When a solvent is used at the time of coating, heat treatment can be performed at the same time as or subsequent to the drying step.To promote the crosslinking reaction, monoamines, diamines, triamines, cyclic amines, alcohols A catalyst such as an amine or an etheramine may be added according to a conventional method.

The content of the charge transporting material in the surface protective layer of the present invention is determined by the molecular weight of the hydroxy group-containing compound and the molecular weight of the isocyanate compound. In order to maintain the electrical characteristics of the photoreceptor while maintaining the mechanical strength, the charge transporting material is added in an amount of 5 to 100 parts by weight of the entire surface protective layer.
The range is preferably 90 parts by weight, more preferably 10 to 60 parts by weight. Since the surface protective layer of the present invention incorporates the charge transporting material by covalent bond, more charge transporting material can be introduced than in the ordinary charge transporting layer.

FIGS. 1 and 2 are schematic sectional views showing a specific example of an electrophotographic photosensitive member having a laminated structure according to the present invention. FIG. 1 shows a charge generating layer 1 on a conductive support 3. Transport layer 2
And a surface protection layer 5. In FIG. 2, an undercoat layer 4 is provided between the conductive support 3 and the charge generation layer 1 of FIG.

Examples of the conductive support include metals such as aluminum, nickel, chromium, and stainless steel; and aluminum, titanium, nickel, chromium, stainless steel, gold, vanadium, tin oxide, indium oxide, and ITO.
(Are these examples of oxides?), A plastic film provided with a thin film such as, or paper or a plastic film coated or impregnated with a conductivity imparting agent. These conductive supports are used in an appropriate shape such as a drum shape, a sheet shape, and a plate shape, but are not limited thereto.

Further, if necessary, the surface of the conductive support can be subjected to various treatments within a range that does not affect the image quality. For example, anodic oxide film treatment, thermal hydroxylation treatment, chemical treatment, coloring treatment, or the like, or irregular reflection treatment such as graining can be performed on the surface.

In the present invention, it is preferable to provide an undercoat layer between the conductive support and the photosensitive layer. This undercoat layer
While charging the photosensitive layer, it prevents charge injection from the conductive support into the photosensitive layer, and acts as an adhesive layer for integrally bonding and holding the photosensitive layer to the conductive support. It has a function of preventing light reflection of the conductive support.

As the binder resin used for the undercoat layer, polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polyurethane resin, melamine resin, benzoguanamine resin, polyimide resin, polyethylene resin,
Polypropylene resin, polycarbonate resin, acrylic resin, methacrylic resin, vinylidene chloride resin, polyvinyl acetal resin, vinyl chloride-vinyl acetate copolymer,
Polyvinyl alcohol resin, water-soluble polyester resin,
Known materials such as nitrocellulose, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, polyacrylic acid, polyacrylamide, zirconium chelate compound, titanyl chelate compound, titanyl alkoxide compound, organic titanyl compound, silane coupling agent, etc. Can be used. These materials can be used alone or in combination of two or more.

Further, fine particles such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, barium titanate, and silicone resin can be mixed in the undercoat layer. As an application method for forming the undercoat layer, a usual method such as a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, a curtain coating method, or the like is employed. The thickness of the undercoat layer is 0.
A suitable range is from 01 to 10 μm, preferably from 0.05 to 2 μm.

The charge generation layer of the present invention can be formed by forming the charge generation material by vacuum evaporation, or by dispersing and applying the charge generation material to a binder resin in an organic solvent. As the charge generating material, amorphous selenium, crystalline selenium-tellurium alloy, selenium-arsenic alloy, other selenium compounds and selenium alloys, granular selenium, zinc oxide, inorganic photoconductive materials such as titanium oxide, phthalocyanine, Organic pigments and dyes such as squarium, anthantrone, perylene, azo, anthraquinone, pyrene, pyrylium salts and thiapyrylium salts are used.

Among these, photoreceptors using phthalocyanine pigments, particularly metal-free phthalocyanine, titanyl phthalocyanine, and gallium phthalocyanine, have high sensitivity at near-infrared semiconductor laser wavelengths (780 to 830 nm) and are stable over a long period of time. Shows electrical characteristics.

Specifically, in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum by CuKα, at least 6.8 °, 12.8 °, 15.8 ° and 26.
Gallium phthalocyanine having a strong diffraction peak at 0 °, at least 7.5 ° in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum by CuKα,
9.9 °, 12.5 °, 16.3 °, 18.6 °, 2
Hydroxygallium phthalocyanine having strong diffraction peaks at 5.1 ° and 28.3 ° (see FIG. 3), CuKα
Angle of the X-ray diffraction spectrum (2θ ± 0.
2 °), at least 7.4 °, 16.6 °, 2
Chlorogallium phthalocyanine having strong diffraction peaks at 5.5 ° and 28.3 ° can be mentioned as a preferable example.

Further, in the visible light wavelength region, an anthrone-based pigment exhibits stable electrical properties over a long period of time, and granular selenium, particularly granular trigonal selenium, exhibits stable electrical properties over a long period of time. The characteristics of higher sensitivity are shown in FIG.

As the binder resin in the charge generation layer, polyvinyl butyral resin, polyvinyl formal resin,
Polyvinyl acetal resins such as partially acetalized polyvinyl acetal resins modified with a part of butyral such as formal or acetoacetal, polyamide resins,
Polyester resin, modified ether type polyester resin,
Polycarbonate resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate copolymer, silicone resin, phenol resin, phenoxy resin, melamine resin, benzoguanamine resin, urea resin,
Polyurethane resin, poly-N-vinyl carbazole resin, polyvinyl anthracene resin, polyvinyl pyrene and the like are used.

Among these, in particular, polyvinyl acetal resin, vinyl chloride-vinyl acetate copolymer, phenoxy resin and modified ether type polyester resin disperse the phthalocyanine or anthantrone pigment and granular trigonal selenium well. The pigment coating does not agglomerate and can stably maintain the dispersion coating solution for a long period of time, facilitating the formation of a uniform coating. As a result, it is possible to provide a photoreceptor with good electrical properties and few image quality defects To However, any resin can be used as long as a film can be formed in a normal state, and the resin is not limited to the above. These binder resins are
They can be used alone or in combination of two or more. The mixing ratio of the charge generation material and the binder resin is 5: 1 to 1 by volume.
A range of 1: 2 is preferred.

Solvents used for preparing the coating solution include methanol, ethanol, n-propanol and n-propanol.
Butanol, benzyl alcohol, methyl cellosolve,
Ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, chlorobenzene, methyl acetate, acetic acid n
Commonly used organic solvents such as -butyl, dioxane, tetrahydrofuran, methylene chloride, chloroform and the like can be used alone or in combination of two or more.

As a method of applying the coating liquid, a commonly used method such as a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, a curtain coating method, etc. is used. be able to.
The thickness of the charge generation layer is 0.01 to 5 μm, preferably 0.1 to 5 μm.
1 to 2.0 μm is appropriate. This thickness is 0.01 μm
If it is thinner, it is difficult to form the charge generation layer uniformly, and if it exceeds 5 μm, the electrophotographic properties tend to be significantly reduced.

The electrophotographic photoreceptor of the present invention obtained as described above maintains excellent repetition stability and high printing durability even when used repeatedly for a long time when applied to a copying machine and a printer. It is possible to provide a copy image of excellent quality.

[0100]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. In the examples and comparative examples, “parts” means parts by weight.

Example 1 10 parts of a zirconium compound (Orgatics ZC540, manufactured by Matsumoto Pharmaceutical Co., Ltd.) and 1 part of a silane compound (A1110, manufactured by Junker Japan Ltd.)
A solution composed of 40 parts of isopropanol and 20 parts of butanol was prepared, applied on an aluminum substrate by a dip coating method, and dried by heating at 150 ° C. for 10 minutes to form a subbing layer having a thickness of 0.1 μm.

Next, as a charge generating material, 1 part of hydroxygallium phthalocyanine having an X-ray diffraction spectrum shown in FIG. 3, 1 part of a carboxyl-modified vinyl chloride-vinyl acetate copolymer (VMCH, manufactured by Union Carbide Co.) and 100 parts of chlorobenzene And a mixture with the glass beads by a sand mill for 1 hour to prepare a coating solution, apply the solution on the undercoat layer by a dip coating method, and heat and dry at 100 ° C. for 10 minutes. A 25 μm charge generation layer was formed.

Table 1 shows the charge transporting polymer compound.
Exemplified compound (V-7) described in No. 3 (weight average molecular weight: 87,0
00) 20 parts and 1 part of the exemplified compound (I-27) shown in Table 2 as a benzidine-based compound as a charge transporting low molecular weight compound, with 60 parts of monochlorobenzene and 30 parts of tetrahydrofuran 30
Of the mixed solution, a coating solution was prepared, coated on the charge generation layer, and dried by heating at 115 ° C. for 60 minutes to form a charge transport layer having a thickness of 20 μm.

Further, 3 parts of a compound of the following structural formula (A) as a charge transporting material having a hydroxy group, and 2 parts of a buret-modified polyisocyanate of a following formula (B) as a compound having an isocyanate (molar ratio: about 3 parts) 3 to 2)
Was dissolved in 5 parts of methyl ethyl ketone and 5 parts of cyclohexanone to prepare a coating solution for the surface protective layer, spray-coated on the charge transport layer and dried at room temperature for 10 minutes, and then heated at 130 ° C. for 60 minutes. A surface protective layer having a thickness of 4 μm was formed and formed on a drum-shaped aluminum substrate.

[0105]

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The photoreceptor thus obtained was used as a test device for a laser beam printer (XP-1 manufactured by Fuji Xerox Co., Ltd.).
5 modified machine), evaluate the initial image quality under an environment of 20 ° C. and 45% RH, repeat printing 100,000 times, evaluate the subsequent image quality, and evaluate the film thickness by eddy current The abrasion loss of the surface protective layer was measured from the difference between the initial thickness and the thickness after printing 100,000 sheets. Table 17 shows the results.

Comparative Example 1 In Example 1, the benzidine compound (I-27) shown in Table 2 of the charge transporting low molecular weight compound was used.
Was prepared in the same manner as in Example 1 except that was removed from the charge transport layer, and the same test was performed. Table 17 shows the results.
It was shown to.

Comparative Example 2 In Example 1, the exemplified compound (V-7) shown in Table 13 and the exemplified compound (I
Instead of -27), 8 parts of a hydrazone compound represented by the following structural formula (C) and 12 parts of a polycarbonate resin represented by the following structural formula (D) are dissolved in 80 parts of monochlorobenzene to form a coating solution for a charge transport layer. Was prepared and applied on the charge generation layer of Example 1 by a dip coating method, heated and dried at 115 ° C. for 60 minutes, and a photoconductor was formed in the same manner as in Example 1 except that a charge transport layer having a thickness of 20 μm was formed. It was fabricated and subjected to a similar test. Table 17 shows the results.

[0109]

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Example 2 In Example 1, the benzidine compound (I-27) shown in Table 2 of the charge transporting low molecular weight compound was used.
In place of the above, a photoreceptor was prepared in the same manner as in Example 1 except that 0.5 part of the exemplified compound (II-28) shown in Table 5 was blended as a triphenylamine-based compound, and a similar test was performed. . Table 17 shows the results.

Example 3 In Example 1, the compound (V-7) exemplified in Table 13 was used as the charge-transporting polymer compound.
Is used instead of the compound (VII-5) shown in Table 16 (weight average molecular weight: 89,000). Instead of the benzidine compound (I-27) shown in Table 2 as a charge transporting low molecular weight compound, Example 1 except that 1.0 part of the exemplified compound (II-30) shown in Table 5 was used as a triphenylamine-based compound.
An electrophotographic photoreceptor was prepared in the same manner as described above, and the same test was performed. Table 17 shows the results.

Comparative Example 3 In Example 3, a triphenylamine-based compound (II-
A photoconductor was prepared in the same manner as in Example 3, except that 30) was removed from the charge transport layer, and the same test was performed. Table 17 shows the results.

Example 4 In Example 3, as a charge transporting material having a hydroxy group in the surface protective layer, 3 parts of a compound of the following formula (E) and isocyanate were used instead of the compound of the above formula (A). As a compound, instead of the compound of the above formula (B), 2 parts of a polyisocyanate represented by the following formula (F) (about 3 to 2 in molar ratio) are dissolved in 5 parts of methyl ethyl ketone and 5 parts of cyclohexanone, and coated on a surface protective layer. A solution was prepared, dip-coated on the charge transport layer of Example 3 and dried at room temperature for 10 minutes.
An electrophotographic photoreceptor was prepared in the same manner as in Example 3 except that a surface protective layer having a thickness of 5 μm was formed by heating for 0 minutes, and the same test was performed. Table 17 shows the results.

[0114]

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[Example 5] In Example 3, 5 parts of antimony oxide-doped tin oxide and 5 parts of acrylic polyol 5
Was mixed with 40 parts of toluene, dispersed in a ball mill for 20 hours, diluted with 20 parts of toluene, and added with 2 parts of a polyisocyanate represented by the structural formula (F) as a compound having an isocyanate to coat the surface protective layer. Prepare the liquid,
After dip coating on the charge transport layer of Example 3 and drying at room temperature for 10 minutes, it was heated at 150 ° C. for 60 minutes to form a film having a thickness of 5 μm.
An electrophotographic photosensitive member was prepared in the same manner as in Example 3 except that the surface protective layer was formed, and the same test was performed. Table 17 shows the results.

Example 6 In Example 1, the exemplified compound (V-7) shown in Table 13 was used as the charge transporting polymer compound.
Instead of using Exemplified Compound (III-8) shown in Table 7 (weight average molecular weight: 92000), an electrophotographic photoreceptor was prepared in the same manner as in Example 1, and the same test was performed. . Table 17 shows the results.

Example 7 In Example 1, the exemplified compound (V-7) shown in Table 13 was used as the charge transporting polymer compound.
Instead of using Exemplified Compound (IV-9) shown in Table 10 (weight average molecular weight: 85,000), an electrophotographic photoreceptor was prepared in the same manner as in Example 1, and a similar test was conducted. . Table 17 shows the results.

Example 8 In Example 1, the compound (V-7) exemplified in Table 13 was used as the charge-transporting polymer compound.
Instead of using Exemplified Compound (VI-2) shown in Table 15 (weight average molecular weight: 87000), an electrophotographic photoreceptor was prepared in the same manner as in Example 1, and a similar test was conducted. . Table 17 shows the results.

[0119]

[Table 17]

As is clear from Table 17, the electrophotographic photoreceptors according to the examples had the surface protective layer formed on the charge transport layer obtained by adding the charge transporting low molecular weight compound to the charge transporting high molecular weight compound. , While maintaining sufficient mechanical strength,
No image defects such as cracks occurred even after long-term use.

[0121]

According to the present invention, by adopting the above-mentioned structure, it is possible to sufficiently improve the mechanical strength without deteriorating the photoelectric characteristics and image quality of the photoreceptor, and as a result, a strong external stress is obtained. It has become possible to maintain high durability even in long-term use under high temperatures.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing one example of the electrophotographic photosensitive member of the present invention.

FIG. 2 is a schematic sectional view showing another example of the electrophotographic photosensitive member of the present invention.

FIG. 3 is a powder X-ray diffraction spectrum diagram (using CuKα) of hydroxygallium phthalocyanine used in Examples.

Claims (5)

[Claims] 1. An electrophotographic photoreceptor having a charge generating layer, a charge transporting layer comprising a charge transporting polymer compound, and a surface protective layer provided on a conductive support, wherein the charge transporting layer comprises a charge transporting low molecule. A photoconductor for electrophotography, comprising a compound. 2. The low-molecular compound having a charge transporting property is a benzidine-based compound represented by the following general formula (I) and / or a triphenylamine-based compound represented by the following general formula (II). The electrophotographic photoreceptor according to claim 1. Embedded image (Wherein R ₁ and R ₁ ′ may be the same or different and represent a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom, and R ₂ , R ₂ ′, R ₃ and R ₃ ′ are the same or different And may represent a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, or a substituted amino group.
k ′, m and m ′ each represent an integer of 1 or 2. ) (In the formula, R ₄ represents a hydrogen atom or a methyl group.
n means an integer of 1 or 2. Ar ₁ and Ar ₂ represent a substituted or unsubstituted aryl group, and as a substituent of Ar ₁ and Ar ₂ , a hydrogen atom, a halogen atom, an alkyl group,
It has an alkoxy group and a substituted amino group. ) 3. The electrophotographic photoreceptor according to claim 1, wherein the charge transporting polymer compound is represented by the following general formulas (III) to (VII). Embedded image (R ₅ and R ₆ each independently represent a hydrogen atom, an alkyl group,
X represents an alkoxy group, a substituted amino group, a halogen atom, or a substituted or unsubstituted aryl group, and X represents a substituted or unsubstituted divalent aryl group. T represents an aliphatic bivalent hydrocarbon group which may be branched. p and q mean an integer of 0 or 1. ) (R ₇ and R ₈ are each independently a hydrogen atom, an alkyl group,
X represents an alkoxy group, a substituted amino group, a halogen atom, or a substituted or unsubstituted aryl group, and X represents a substituted or unsubstituted divalent aryl group. T represents an aliphatic bivalent hydrocarbon group which may be branched. r and s each represent an integer of 0 or 1. ) (Wherein A is represented by the above general formula (III) or (IV), Y represents a divalent hydrocarbon group, t represents an integer in the range of 1 to 5, and u represents It means an integer in the range of 5 to 5000.) (Wherein A is represented by the above general formula (III) or (IV), and Y, Y ′ and Y ″ represent a divalent hydrocarbon group. V is an integer in the range of 1 to 5) And w is 5 to 500
It means an integer in the range of 0. ) (Wherein A is represented by the above general formula (III) or (IV), and Y, Y ′ and Y ″ represent a divalent hydrocarbon group. X is an integer in the range of 1 to 5) And y is from 5 to 500
0 means an integer in the range of 0, z means an integer in the range of 1 to 3500, y + z is an integer of 5 to 5000, and 1> y /
It is a number that satisfies (y + z) ≧ 0.3. ) 4. The surface protection layer according to claim 1, wherein the surface protection layer comprises conductive metal oxide particles and a thermosetting resin.
4. The electrophotographic photoreceptor according to any one of the above items 3. 5. The surface protective layer comprises a charge transporting material having a reactive functional group and a compound having a reactive functional group for the charge transporting material, and reacts with each other by heating to form a crosslink in a network. The electrophotographic photoreceptor according to any one of claims 1 to 4, wherein