JPH07120051B2 - Electrophotographic photoreceptor - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electrophotographic photoreceptor having a charge generation layer and a charge transport layer.

2. Description of the Related Art Conventionally, electrophotographic photoreceptors using organic photoconductors have been studied variously because they have advantages such as pollution-free, high productivity, and low cost. Substances that absorb light to generate electric charges have poor charge retention, and conversely, substances that have good charge retention and have excellent film-forming properties generally have almost no photoconductivity by visible light. . In order to solve this problem, a charge-generating layer that absorbs visible light to generate an electric charge on the photoconductor, and a laminated type photoconductive layer having a layer structure in which a charge-transporting layer that transports the charge is functionally separated. Is being done. A large number of charge-generating substances and electron-transporting substances have been proposed, and examples of charge-transporting substances include amine compounds, hydrazone compounds, pyrazoline compounds, oxazole compounds, oxadiazole compounds, stilbene compounds, and carbazole compounds. Various things are known.

Conventionally, as a binder resin for the charge transport layer, for example, JP-A-
Polymer resins such as polymethylmethacrylate, polyester, and polycarbonate as disclosed in JP-A-57-4051 are generally used. These polymer resins are compatible with various charge-transporting substances and give good electrical characteristics, but have low hardness and are vulnerable to mechanical external force, and have limited the life of the photoconductor due to surface abrasion and scratches. .

On the other hand, in recent years, there has been proposed a method of forming a functional film by doping organic compound molecules when a metal oxide ceramic is synthesized by using a sol-gel method. The film thus produced has high hardness and excellent wear resistance.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention By the way, a film produced by a sol-gel method using a metal alkoxide has features of high hardness and excellent abrasion resistance. However, when it is applied to the charge transport layer, the charge transport material is not compatible with each other, and the charge transport property cannot be provided. Therefore, it can be used as a charge transport layer forming material in an electrophotographic photoreceptor. There wasn't.

The present invention has been made in view of the above circumstances. Therefore, an object of the present invention is to provide an electrophotographic photoreceptor having a charge transport layer having high hardness and excellent wear resistance.

Means and Actions for Solving the Problems The inventors of the present invention, as a result of the investigation, substituted a part of the alkoxy group of the metal alkoxide with a hydrophobic substituent, and the hydrophobic substituent was micellar-assembled gel. To form a body and have an affinity for hydrophobic molecules,
It has been found that it becomes possible to make various functional molecules compatible with each other in the gel, and the present invention has been completed.

A first aspect of the present invention is an electrophotographic photosensitive member comprising a conductive support and a charge generation layer and a charge transport layer provided on the conductive support, wherein the charge transport layer has the following general formulas (I), (II) and (III). ) A matrix formed by polycondensation of at least one metal alkoxide selected from the group represented by), and a charge transport material having an affinity for the group X ₁ or X ₂ contained in the metal alkoxide. And

(In the formula, M ₁ represents a trivalent metal atom, M ₂ represents a tetravalent metal atom or a carbon atom, and R ₁ , R ₂ and R ₃ are each a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Represents R ₁ ,
At least one of R ₂ and R ₃ represents an alkyl group having 1 to 6 carbon atoms, X ₁ and X ₂ are each an alkyl group having 5 or more carbon atoms which may have a substituent, an aryl group, an aralkyl group,
An acyl group, a heterocyclic group, or an unsaturated hydrocarbon group, or X ₁ and X ₂ represent a group which is bonded to each other to form a ring structure) The second aspect of the present invention is a conductive support. In an electrophotographic photosensitive member having a charge generation layer and a charge transport layer provided thereon, the charge transport layer is at least a metal alkoxide selected from the group represented by the following general formulas (I), (II) and (III). Matrix formed by polycondensation of one kind with at least one kind of metal alkoxide selected from the group represented by the following general formulas (IV) and (V), and a group X ₁ or X contained in the metal alkoxide It is characterized by comprising a charge transport material having an affinity for ₂ .

(In the formula, M ₃ represents a trivalent metal atom, M ₄ represents a tetravalent metal atom or a carbon atom, and R ₄ , R ₅ and R ₆ represent a hydrogen atom and an alkyl group having 1 to 4 carbon atoms, respectively. Represents a group, Y is a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, an amino group, an alkyl group having 1 to 4 carbon atoms which may have a substituent, an aryl group which may have a substituent, It represents an acyl group, a heterocyclic group, or an unsaturated hydrocarbon group) In the present specification, the "metal alkoxide" means
It is also defined as meaning when M ₂ and M _{4 in the} above general formulas (II), (III) and (V) represent a carbon atom.

In the electrophotographic photosensitive member of the present invention, as the conductive support, for example, a metal pipe, a metal plate, a metal sheet, a metal foil, a polymer film subjected to a conductive treatment, a vapor deposition layer of a metal such as Al is provided. A molecular film, a metal oxide such as SnO ₂ , a polymer film coated with a quaternary ammonium salt, or paper is used.

Although the charge generation layer and the charge transport layer are formed on the conductive support, the order of stacking them may be any, and the case where the charge transport layer is the upper layer is preferable.

The charge generation layer may be, for example, one obtained by vapor deposition of a charge generation substance on a conductive support, or formed by applying a coating liquid containing a charge generation substance and a binder resin as main components. It may be the one that was given.

As the charge generating substance and the binder resin, any known substances can be used. For example, as the charge generation material, an inorganic semiconductor such as tri-Se, an organic semiconductor such as polyvinylcarbazole, a bisazo compound, a trisazo compound, a phthalocyanine compound, a pyrylium compound,
Organic pigments such as squarium compounds can be used, and as the binder resin, polystyrene, silicone resin, polycarbonate resin, acrylic resin, methacrylic resin, polyester, vinyl polymer, celluloses, alkyd resin and the like can be used.

The film thickness of the charge generation layer is set to about 0.05 to 10 μm.

On the other hand, the charge transport layer comprises at least one metal alkoxide selected from the group represented by the general formulas (I), (II) and (III), or the metal alkoxide and the general formulas (IV) and (V). ) And at least one metal alkoxide selected from the group represented by the formula (1) are dissolved in a suitable solvent together with the charge transport material to prepare a solution, which is applied onto the charge generation layer and then subjected to a suitable method. Thus, for example, stirring is carried out at room temperature in the presence of water, a catalyst, etc., if desired. Also,
If desired, the reaction can be carried out by heating to cause polycondensation, and the reaction can be carried out by selecting a method suitable for the selected system.

In the present invention, the metal atom of the metal alkoxide represented by the above general formulas (I) to (V) includes Al, B, G
Those selected from a, Y, Fe, Si, Ge, Sn, Ti and Zr can be preferably used.

The following are examples of metal alkoxides that can be preferably used in the present invention.

Metal alkoxide represented by the general formula _{(I): C 5 H 11} -Al (OCH 3) 2, C 6 H 13 -Al (OCH 3) 2 C 7 H 15 -Al (OCH 3) 2, C 8 H 17 _{-Al (OCH 3) 2 C 9} H 19 -Al (OCH 3) 2, C 10 H 21 -Al (OCH 3) 2 C 15 H 31 -Al (OCH 3) 2, C 20 H 41 -Al (OCH ₃ ) ₂ C ₂₅ H ₅₁ -Al (OCH ₃ ) ₂ ,, C ₁₀ H ₂₁ -Al (OC ₂ H ₅ ) ₂ C ₂₀ H ₄₁ -Al (OC ₂ H ₅ ) ₂ ,, C ₂₅ H ₅₁ -Al (OC _{2 H 5) 2 C 10 H} 21 -Al (OC 3 H 7) 2, C 10 H 21 -Al (OC 4 H 9) 2 C 10 H 21 -Al (OC 5 H 11) 2, _{CH 2 = CH (CH 2)} 3 -Al (OCH 3) 2, CH 3 CH = CH (CH 2) 2 -Al (OCH 3) 2, CH 2 = CHCH 2 CH = CH-Al (OCH 3) 2 _{, NH 2 (CH 2) 5} -Al (OCH 3) 2, C 5 H 11 -B (OCH 3) 2 C 10 H 21 -B (OCH 3) 2, C ₅ H ₁₁ -Ga (OCH ₃ ) ₂ , C ₁₀ H ₂₁ -Ga (OCH ₃ ) ₂ C ₅ H ₁₁ -Y (OCH ₃ ) ₂ C ₁₀ H ₂₁ -Y (OCH ₃ ) ₂ , C ₅ H ₁₁ -Fe (OCH ₃ ) ₂ , C ₁₀ H ₂₁ -Fe (OCH ₃ ) ₂ Metal alkoxide represented by the general formula (II): C ₅ H ₁₁ -Si (OCH ₃ ) ₃ , C ₁₀ H ₂₁ -Si (OCH ₃ ) ₃ C ₁₅ H ₃₁ -Si (OCH ₃ ) ₃ , C ₂₀ H _{41 -Si (OCH 3) 3 C 5} H 11 -Si (OC 2 H 5) 3, C 20 H 41 -Si (OC 2 H 5) 3 C 20 H 41 -Si (OC 3 H 7) 3, C 20 _{H 41 -Si (OC 4 H 9} ) 3 C 20 H 41 -Si (OC 5 H 11) 3, _{CH 2 = CHCH 2 CH = CHSi} (OCH 3) 3, NH 2 (CH 2) 5 Si (OCH 3) 3, _{CH 2 = CHSi (OC 2 H} 5) 3, CH 2 = CHSi (OCH 3) 3 HSC ₃ H ₆ Si (OCH) ₃ , NH ₂ C ₂ H ₄ NHC ₃ H ₆ Si (OCH ₃ ) ₃ , NH ₂ CONHC ₃ H ₆ Si (OC ₂ H ₅ ) ₃ , NH ₂ C ₃ H ₆ Si ( OC ₂ H ₅ ) ₃ , ClC ₃ H ₆ Si (OCH ₃ ) ₃ , C ₅ H ₁₁ -C (OCH ₃ ) ₃ , C ₁₅ H ₃₁ -C (OCH ₃ ) _{3 C 5 H 11 -Ge (OCH 3} ) 3 C 20 H 41 -Ge (OCH 3) 3, C ₅ H ₁₁ -Sn (OCH ₃ ) ₃ , C ₂₀ H ₄₁ -Sn (OCH ₃ ) ₃ C ₅ H ₁₁ -Ti (OCH ₃ ) ₃ C ₅ H ₁₁ -Zr (OCH ₃ ) ₃ , C ₂₀ H ₄₁ -Zr (OCH ₃ ) ₃ The metal alkoxide represented by the general formula (III): Further, the general formulas (IV) and (V) used together with the metal alkoxides represented by the above general formulas (I) to (III)
Examples of the metal alkoxide represented by are as follows.

Metal alkoxide represented by the general formula (IV): Al (OCH ₃ ) ₃ , Al (OC ₂ H ₅ ) ₃ , Al (OC ₃ H ₇ ) ₃ , Al (OC ₄ H ₉ ) _{3 B (OCH 3) 3, B} (OC 4 H 9) 3, Ga (OCH ₃ ) ₃ ,, Ga (OC ₄ H ₉ ) ₃ , Y (OCH ₃ ) ₃ , Y (OC ₄ H ₉ ) ₃ , Fe (OCH ₃ ) ₃ , Fe (OC ₄ H ₉ ) ₃ , Metal alkoxide represented by the general formula _{(V): Si (OCH 3} ) 4, Si (OC 2 H 5) 4 Si (OC 3 H 7) 4, Si (OC 4 H 9) 4 C (OCH ₃ ) ₄ , C (OC ₄ H ₉ ) ₄ Ge (OCH ₃ ) ₄ , Ge (OC ₄ H ₉ ) ₄ Sn (OCH ₃ ) ₄ , Sn (OC ₄ H ₉ ) ₄ Ti (OCH ₃ ) ₄ , Ti (OC ₄ H ₉ ) ₄ Zr (OCH ₃ ) ₄ , Zr (OC ₄ H ₉ ) ₄ When the metal alkoxides represented by the general formulas (IV) and (V) are used, the above general formulas (I) to (III)
Used in the range of 0 to 98 mol% with respect to the metal alkoxide.

Further, as the charge transport substance, a hydrophobic substituent X ₁ or X ₂
Any substance having an affinity with can be used. For example, oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5-triphenyl-pyrazoline, 1-
A pyrazoline derivative such as [pyridyl- (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazoline, an aromatic tertiary amino compound such as triphenylamine or dibenzylaniline, N, N'-diphenyl-N, N'-bis (3-methylphenyl)-[1,1-
Biphenyl] -4,4'-diamine and other aromatic tertiary diamino compounds, 3- (4'-dimethylaminophenyl) -5,
1,2,4-triazine derivatives such as 6-di (4'-methoxyphenyl) -1,2,4-triazine, hydrazone derivatives such as 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, 2-phenyl-4 -Quinazoline derivatives such as styryl-quinazoline, benzofuran derivatives such as 6-hydroxy-2,3-di (p-methoxyphenyl) benzofuran, α such as p- (2,2-diphenylvinyl) -N, N-diphenylaniline − Stilbene derivatives, “Journal of Ima”
Ging Science) 29: 7-10 (1985), carbazole derivatives such as N-ethylcarbazole, poly-N-vinylcarbazole and its derivatives,
Known charge transport materials such as poly-γ-carbazolyl ethyl glutamate and its derivatives, as well as pyrene, polyvinyl pyrene, polyvinyl anthracene, polyvinyl acridine, poly-9-biphenyl anthracene, pyrene-formaldehyde resin and ethylcarbazole-formaldehyde resin. Can be used, but is not limited thereto. These charge transport materials can be used alone or in combination of two or more.

These charge transport materials are the same as the above metal alkoxides.
It is preferably contained in a proportion of 20 to 80% by volume.

In the charge-transporting layer formed as described above, the charge-transporting substance is in a state of being dispersed in the matrix formed by the condensation polymerization of the metal alkoxide,
As shown in FIG. 1 (FIG. 1 is a model in the case of silicon), the content state is the hydrophobic substituent X formed in the matrix composed of the condensation polymer of metal alkoxide.
It is presumed that the charge transport material A having affinity with the hydrophobic substituent is incorporated in the micelle structure in which ₁ (X ₂ ) is assembled. Therefore, in the electrophotographic photoreceptor of the present invention, the charge transport material is contained in the charge transport layer in a stabilized state.

The thickness of the charge transport layer is set to about 2 to 100 μm.

In the electrophotographic photosensitive member of the present invention, a barrier layer may be provided on the conductive support. The barrier layer is effective to prevent unnecessary injection of charges from the conductive support and has an effect of improving image quality. As a material for forming the barrier layer, a metal oxide such as aluminum oxide or an acrylic resin, a phenol resin, a polyester resin,
Examples include polyurethane.

Examples Hereinafter, the present invention will be described with reference to Examples.

Example 1 An aluminum pipe was used as a conductive base material, and 10 parts by weight of polyamide resin, 150 parts by weight of methanol, and 40 parts of water were used.
A coating liquid consisting of parts by weight was applied by a drawing coating method and dried to form an undercoat layer having a film thickness of 1 μm. Then, a charge generation layer was formed. That is, a mixture of 90 parts by weight of trigonal selenium, 10 parts by weight of polyvinyl butyral resin and 300 parts by weight of n-butanol was dispersed using an attritor, and 2 parts by weight of n-butanol was added to 1 part by weight of the obtained dispersion. Part of the dispersion is diluted and applied onto the undercoat layer by the drawing method and dried to a film thickness of 0.3μ.
m charge generating layer was formed.

Next, N, N'-diphenyl-N, N'-bis (3-methylphenyl)-[1,1'-biphenyl] -4,4'-diamine 7
Parts by weight, 10 parts by weight of chlorophenyltriethoxysilane,
3 parts by weight of tetraethoxysilane was added to 14 parts of monochlorobenzene.
It was dissolved in 0 part by weight to obtain a coating solution. This coating solution is applied onto the charge generation layer by a drawing coating method,
The film was dried at 0 ° C. for 90 minutes to form a charge transport layer having a film thickness of 14 μm, and an electrophotographic photoreceptor was prepared.

Various electrophotographic characteristics and printing durability of the obtained electrophotographic photosensitive member were evaluated. That is, the photoconductor inflow current is −
It was charged to 10 μA, and the surface potential of the photosensitive member was measured 1 second after charging, which was defined as VDDP. After that, perform static elimination with a tungsten lamp, measure the potential after static elimination, and use this as the residual potential.
It was VRP. Next, adjust the inflow current of the photoconductor and set VDDP to -5
It is adjusted so that it becomes 00V, and after 0.3 seconds after charging, it is exposed to monochromatic light of 550 nm while changing the light amount, and the light amount at which the potential becomes -250V 0.7 seconds after exposure (1 second after charging), The light sensitivity was E1 / 2.

In addition, for the evaluation of printing durability, an electrophotographic copying machine (FX5014, manufactured by Fuji Xerox Co., Ltd.) was used to evaluate the presence or absence of image defects due to abrasion and scratches on the surface of the photoconductor during 100,000 copy runs, and the amount of surface polishing. did.

The results obtained are shown in Table 1.

Example 2 After forming an undercoat layer and a charge generation layer in the same manner as in Example 1, a charge transport layer was formed as follows to prepare an electrophotographic photoreceptor.

6 parts by weight of N, N'-diphenyl-N, N'-bis (3-methylphenyl)-[1,1'-biphenyl] -4,4'-diamine, an alkoxysilane represented by the following structural formula 10 parts by weight and 4 parts by weight of tetraethoxysilane were dissolved in 140 parts by weight of monochlorobenzene to obtain a coating solution, which was applied onto the charge generation layer by a drawing coating method,
The film was dried at 170 ° C. for 90 minutes to form a charge transport layer having a film thickness of 15 μm.

The electrophotographic photoreceptor thus obtained was evaluated for electrophotographic characteristics and printing durability in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 After forming an undercoat layer and a charge generation layer in the same manner as in Example 1, a charge transport layer was formed as follows to prepare an electrophotographic photoreceptor.

4 parts by weight of N, N'-diphenyl-N, N'-bis (3-methylphenyl)-[1,1'-biphenyl] -4,4'-diamine, polycarbonate resin (bisphenol Z type: P
6 parts by weight of C (Z) was dissolved in 90 parts by weight of monochlorobenzene to obtain a coating solution, which was applied onto the above charge generation layer by a drawing coating method and dried at 170 ° C. for 90 minutes. To form a charge transport layer having a thickness of 13 μm.

The electrophotographic photoreceptor thus obtained was evaluated for electrophotographic characteristics and printing durability in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2 After forming an undercoat layer and a charge generation layer in the same manner as in Example 1, a charge transport layer was formed as follows to prepare an electrophotographic photoreceptor.

4 parts by weight of N, N'-diphenyl-N, N'-bis (3-methylphenyl)-[1,1'-biphenyl] -4,4'-diamine, polycarbonate resin (bisphenol A type: P
6 parts by weight of C (A) was dissolved in 90 parts by weight of monochlorobenzene to obtain a coating solution, which was applied onto the above charge generation layer by a drawing coating method and dried at 170 ° C. for 90 minutes. To form a charge transport layer having a thickness of 13 μm.

The electrophotographic photoreceptor thus obtained was evaluated for electrophotographic characteristics and printing durability in the same manner as in Example 1. The results are shown in Table 1.

EFFECTS OF THE INVENTION The electrophotographic photosensitive member of the present invention is excellent in durability because the charge transporting material is stably contained in the matrix of the condensation polymer of the metal alkoxide having high hardness in the charge transporting layer. Form images with excellent image quality during repeated copying operations for a long period of time.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a model of the structure of the charge transport layer in the present invention.

Claims (3)

[Claims] 1. An electrophotographic photoreceptor comprising a charge generating layer and a charge transporting layer provided on a conductive support, wherein the charge transporting layer is represented by the following general formulas (I), (II) and (III). An electrophotography comprising a matrix formed by polycondensation of at least one metal alkoxide selected from the group, and a charge transport material having an affinity for the group X ₁ or X ₂ contained in the metal alkoxide. Photoconductor. (In the formula, M ₁ represents a trivalent metal atom, M ₂ represents a tetravalent metal atom or a carbon atom, and R ₁ , R ₂ and R ₃ are each a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Represents R ₁ ,
At least one of R ₂ and R ₃ represents an alkyl group having 1 to 6 carbon atoms, X ₁ and X ₂ are each an alkyl group having 5 or more carbon atoms which may have a substituent, an aryl group, an aralkyl group,
An acyl group, a heterocyclic group, or an unsaturated hydrocarbon group, or X ₁ and X ₂ represent a group which is bonded to each other to form a ring structure) 2. An electrophotographic photosensitive member comprising a conductive support and a charge generation layer and a charge transport layer provided on the conductive support, wherein the charge transport layer is represented by the following general formulas (I), (II) and (III). A matrix formed by polycondensation of at least one metal alkoxide selected from the group and at least one metal alkoxide selected from the group represented by the following general formulas (IV) and (V), and the metal: An electrophotographic photoreceptor comprising a charge-transporting substance having an affinity for a group X ₁ or X ₂ contained in an alkoxide. (In the formula, M ₁ , M ₂ , R ₁ , R ₂ , R ₃ , X ₁ and X ₂ each have the same meaning as described above) (In the formula, M ₃ represents a trivalent metal atom, M ₄ represents a tetravalent metal atom or a carbon atom, and R ₄ , R ₅ and R ₆ represent a hydrogen atom and an alkyl group having 1 to 4 carbon atoms, respectively. Represents a group, Y is a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, an amino group, an alkyl group having 1 to 4 carbon atoms which may have a substituent, an aryl group which may have a substituent, Represents an acyl group, a heterocyclic group, or an unsaturated hydrocarbon group) 3. The metal atom of the metal alkoxide is Al, B,
The electrophotographic photosensitive member according to claim 1 or 2, which is selected from Ga, Y, Fe, Si, Ge, Sn, Ti, and Zr.