JPH067267B2 - Electrophotographic photoconductor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a photoconductor for electrophotography, and more specifically,
The present invention relates to an electrophotographic photoreceptor provided with a photosensitive layer containing a disazo pigment as a substance that generates a charge carrier when irradiated with light (hereinafter referred to as "charge generating substance").

2. Description of the Related Art As an electrophotographic photoconductor, an inorganic photoconductor using selenium and its alloy, a photoconductor in which dye-sensitized zinc oxide is dispersed in a binder resin, or an organic photoconductor is used. Typical examples include those using a charge transfer complex of 2,4,7-trinitro-9-fluorenone (hereinafter referred to as “TNF”) and poly-N-vinylcarbazole (hereinafter referred to as “PVK”). ing.

However, these photoreceptors have many advantages and, at the same time, have various drawbacks. For example, selenium photoconductors that are widely used at present have difficult manufacturing conditions, are expensive to manufacture, are difficult to process into a belt because they are not flexible, and are sensitive to heat and mechanical shock. Therefore, handle with care. Zinc oxide photoconductor can be manufactured by applying it to a support using inexpensive zinc oxide, but the cost is low, but generally sensitivity is low, surface smoothness, hardness, tensile strength, abrasion resistance, etc. There is a mechanical defect, and there are many problems in durability as a photoreceptor for a plain paper copying machine which is usually used repeatedly. Further, a photoconductor using a charge transfer complex of TNF and PVK has low sensitivity and is not suitable as a photoconductor for a high speed copying machine.

In recent years, extensive research has been conducted in order to eliminate the drawbacks of these photoconductors, and in particular, various organic photoconductors have been proposed. Above all, a laminated type photoreceptor in which a thin film of an organic pigment is formed on a conductive support (charge generation layer) and a layer (charge transfer layer) mainly containing a charge transfer substance is formed on the conductive support is a conventional organic material type. Compared with the above-mentioned photoconductor, it is attracting attention as a photoconductor for a plain paper copying machine because of its high general sensitivity and stable charging property, and it is partially put to practical use.

As this type of conventional laminated type photoreceptor, (1) a thin layer obtained by vacuum-depositing a perylene derivative as a charge generation layer and an oxadiazole derivative as a charge transport layer (see USP3871882) (2) Charge A thin layer formed by applying an organic amine solution of chlordian blue is used as a generation layer, and a hydrazone compound is used as a charge transport layer (see Japanese Patent Publication No. 55-42380). (3) Distyryl as a charge generation layer It is known that a thin layer formed by coating an organic solvent dispersion of a benzene-based disazo compound is used and a hydrazone compound for a charge carrier layer is used (see JP-A-55-84943).

However, it is a fact that even the laminated type photoreceptor of this type has many advantages and various drawbacks at the same time. That is, it has the following drawbacks.

The photoreceptor using the perylene derivative and the oxadiazole derivative shown in (1) has a high manufacturing cost because the charge generation layer is formed by vacuum deposition.

The photoreceptor using the chlordyan blue and the hydrazone compound shown in (2) needs to use an organic amine (for example, ethylenediamine), which is generally difficult to handle, as a coating solvent for forming the charge generation layer. There are many downsides. In addition, since the visible wavelength range of the photosensitive wavelength is approximately 450 to 660 nm, the image reproducibility of the red original document was poor. Therefore, when actually mounted in a copying machine, a filter for cutting red light is necessary, which is a disadvantage in designing the copying machine.

The photoconductor using the distyrylbenzene-based disazo compound and the hydrazone compound shown in (3) is very advantageous in production since a charge generation layer can be easily formed by coating a dispersion of the disazo compound. , (2), the photosensitive wavelength range is about 450 to 700 nm, so that it has a drawback that the image reproducibility of a red document is poor.

Configuration The electrophotographic photoreceptor of the present invention is characterized in that a photosensitive layer containing a disazo pigment represented by the following general formula (I) as a charge generating substance is provided on a conductive support.

(In the formula, A represents a coupler residue.) Incidentally, in view of the above-mentioned conventional drawbacks, the present inventor can easily manufacture and has high sensitivity, and the photosensitive wavelength range is in a short wavelength range (that is, the image of a red original document). As a result of extensive studies for the purpose of developing an electrophotographic photoreceptor having excellent reproducibility, as a result of using a specific disazo compound represented by the general formula (I) as a charge generating substance, It has been found that what can be achieved is that the present invention has been completed accordingly.

As the coupler in the general formula (I), for example, phenols, naphthols and other aromatic hydrocarbon compounds having a hydroxyl group and a heterocyclic compound having a hydroxyl group, an aromatic hydrocarbon compound having an amino group and a heterocyclic compound having an amino group Used as cyclic compounds, aromatic hydrocarbon compounds having a hydroxyl group and amino group such as aminonaphthols and heterocyclic compounds, fatty acids, or compounds having an aromatic enol ketone group (compounds having an active methylene group) Preferably, the coupler residue A has the following general formulas (II), (III), (IV), (V), (VI), (VII), (VIII) and (I
It is represented by the general formulas (X), (X), (XI), and (XII).

[In the above formulas (II), (III), (IV) and (V), X, Y, Z,
m and n respectively represent the following.

(R ₁ and R ₂ represent hydrogen or a substituted or unsubstituted alkyl group, and R ₃ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group.) Y ₁ : hydrogen, halogen, substituted or Unsubstituted alkyl group, substituted or unsubstituted alkoxy group, carboxy group, sulfo group, substituted or unsubstituted sulfamoyl group or (R ₄ represents hydrogen, an alkyl group or a substituted product thereof, a phenyl group or a substituted product thereof, and Y ₂ is a hydrocarbon ring group or a substituted product thereof, a heterocyclic group or a substituted product thereof, or (Wherein R ₅ represents a hydrocarbon ring group or a substituted product thereof, a heterocyclic group or a substituted product thereof, a styryl group or a substituted product thereof, R ₆ represents hydrogen, an alkyl group, a phenyl group or a substituted product thereof, or ₅ and R ₆ may form a ring together with the carbon atom bonded to them. ) Z: hydrocarbon ring or a substituted product thereof or a heterocycle or a substituted product thereof, n: an integer of 1 or 2 m: an integer of 1 or 2] [In the formulas (VI) and (VII), R ₇ represents a substituted or unsubstituted hydrocarbon, and X is the same as defined above. ] [In the formula, R ₈ represents an alkyl group, a carbamoyl group, a carboxyl group or an ester thereof, Ar ₁ represents a hydrocarbon ring group or a substituted product thereof, and X is the same as defined above. ] [In the above formulas (IX) and (X), R ₉ represents hydrogen or a substituted or unsubstituted hydrocarbon group, and Ar ₂ represents a hydrocarbon ring group or a substituted product thereof. Examples of the hydrocarbon ring represented by Z in the general formula (II), (III), (IV) or (V) include a benzene ring and a naphthalene ring.
Examples of the heterocycle include indole ring, carbazole ring, benzolane ring and the like. Examples of the substituent on the ring of Z include a halogen atom such as a chlorine atom and a bromine atom, and an alkoxy group.

The hydrocarbon ring group for Y ₂ or R ₅ is a phenyl group, a naphthyl group, an anthryl group, a pyrenyl group or the like, and the heterocyclic group is a pyridyl group, a cenyl group, a furyl group, an indolyl group, a benzofuranyl group or a carbazolyl group. Group, dibenzofuranyl group and the like, and further, R ₅
Examples of the ring formed by combining R ₆ and R ₆ include a fluorene ring.

Y ₂ or R ₅ hydrocarbon ring group or heterocyclic group or R
Examples of the substituent in the ring formed by ₅ and R ₆ include an alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group, a methoxy group, an ethoxy group, a propoxy group,
Alkoxy group such as butoxy group, halogen atom such as chlorine atom and bromine atom, dialkylamino group such as dimethylamino group and diethylamino group, diaralkylamino group such as dibenzylamino group, halomethyl group such as trifluoromethyl group, nitro group, a cyano group, a carboxyl group or an ester thereof, a hydroxyl group, such as sulfonate groups, such as -SO ₃ N _a and the like.

Examples of the substituted phenyl group represented by R ₄ include halogen atoms such as chlorine atom and bromine atom.

Representative examples of the hydrocarbon group for R ₇ or R ₉ include alkyl groups such as methyl group, ethyl group, propyl group and butyl group, aralkyl groups such as benzyl group, aryl such as phenyl group and substituted products thereof. it can.

Examples of the substituent in the hydrocarbon group of R ₇ or R ₉ include an alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group, an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group and a butoxy group, a chlorine atom, Examples include halogen atoms such as bromine atom, hydroxyl group, and nitro group.

Typical examples of the hydrocarbon ring group for Ar ₁ or Ar ₂ include a phenyl group and a naphthyl group, and the substituents in these groups include a methyl group, an ethyl group,
Alkyl group such as propyl group and butyl group, methoxy group,
Examples thereof include alkoxy groups such as ethoxy group, propoxy group and butoxy group, halogen atoms such as nitro group, chlorine atom and bromine atom, dialkylamino groups such as cyano group, dimethylamino group and diethylamino group.

Further, in X, a hydroxyl group is particularly suitable.

Among the above coupler residues, preferred is the above general formula (I
II), (VI), (VII), (VIII), (IX) and (X), among which X in the general formula is preferably a hydroxyl group. In addition, among these, the general formula (XI) (Y ₁ and Z are the same as above), and a coupler residue represented by (Z, Y ₂ and R ₂ are the same as above).

Furthermore, among the above preferred coupler residues, the general formula (XIII) or (XIV) (Z, R ₂ , R ₅ and R ₆ are the same as above, and R
Examples of ₁₀ are the above-mentioned Y ₂ substituents. ) Is suitable.

Specific examples of the disazo pigment used in the present invention as described above are shown by the structural formulas as follows.

By using the disazo pigment of the present invention as described above, a highly sensitive electrophotographic photoreceptor can be easily manufactured.

The disazo pigment of the present invention is, for example, 3,3'-diamino-4,4'-dichlorobenzophenone produced by reducing 3,3'-dinitro-4,4'-dichlorobenzophenone by a conventional method. It can be easily produced by diazotizing to give a tetrazonium salt, and subjecting the tetrazonium salt and a corresponding coupler to a coupling reaction by reacting a base in a suitable organic solvent such as N, N-dimethylformamide. As an example thereof, a production example of the above-mentioned No. 1 disazo pigment will be shown, but other disazo pigments can be easily produced according to this production example except that the coupler is changed.

Production example Production of tetrazonium salt 3,3'-dia was added to hydrochloric acid consisting of 200 m of water and 52 m of concentrated hydrochloric acid.
Add 28.1 g of mino-4,4'-dichlorobenzophenone,
After heating to 60 ° C for 1 hour, cool to 0 ° C and then
Then, 14.9 g of sodium sulfite was dissolved in 50 m of water.
The solution was added dropwise at a temperature of 0 ° C to 5 ° C over 20 minutes. That
After stirring at the same temperature for 30 minutes, 42% borofluoride was added to this reaction solution.
Hydrochloric acid 90m was added, the precipitated crystals were separated, washed with water,
37.7 g (78.7% yield) of tetrazonium difluoro after drying
Light brown crystals of borate were obtained. Infrared absorption spectrum
(KBr tablet method) is 2280 cm^-1To N₂ Absorption band based on
But 1700 cm^-1An absorption band based on> C = O was observed.

Preparation of Disazo Pigment No. 1 1.20 g of the tetrazonium salt prepared as described above and 1.32 g of 2-hydroxy-3-naphthoic acid anilide (twice the molar amount of the tetrazonium salt) as a coupling component were cooled with N, N- Dissolve in 150 m of dimethylformamide, and add a solution of 0.82 g of sodium acetate and 7 m of water to the solution.
The mixture was added dropwise at a temperature of -10 ° C over 20 minutes, cooling was stopped, and the mixture was further stirred at room temperature for 3 hours. Thereafter, the formed precipitate was collected, washed with 200 m of N, N-dimethylformamide heated to 80 ° C three times, and then with 700 m of water twice, dried at 80 ° C under a reduced pressure of 2 mmHg, and dried. -1 compound
1.55 g (yield 74.9%) of the No. 1 disazo compound was obtained. The disazo compound had a red-orange powder appearance and its infrared absorption spectrum (KBr tablet method) is shown in FIG.

In the electrophotographic photoreceptor of the present invention, the disazo pigment is used as a charge generating substance in the photosensitive layer, and a typical constitution of this photoreceptor is shown in FIGS. 1 and 2.

The photoreceptor shown in FIG. 1 has a disazo pigment on a conductive support 11.
A laminate type photosensitive layer 191 including a charge generation layer 15 mainly composed of 13 and a charge transport layer 17 mainly composed of a charge carrier substance is provided.

In the photoreceptor of FIG. 1, the imagewise exposed light passes through the charge transport layer and reaches the charge generation layer 15, where the disazo pigment is present.
On the other hand, the charge is generated at 13, while the charge transfer layer 17 receives and injects the charge, and the disazo pigment 13 generates the charge necessary for light attenuation, and the charge transfer is performed by the charge transfer. It is a mechanism called in layer 17.

The photoreceptor shown in FIG. 2 comprises a conductive support 11 and a photosensitive layer 192 mainly comprising a disazo pigment 13, a charge carrier substance and an insulating binder. Here again, the disazo pigment 13 is a charge generating substance.

As another photoreceptor, the charge generation layer and the charge transport layer in FIG. 1 may be reversed.

The thickness of the photosensitive layer is as shown in FIG. 1, and the thickness of the charge generation layer 15 is preferably 0.01 to 5 μ, more preferably 0.05 to 2 μ. If this thickness is 0.01 μm or less, the generation of electric charges is not sufficient, and if it is 5 μm or more, the residual potential is high and it cannot be put to practical use. The thickness of the charge transport layer 17 is preferably 3 to 50 μ, more preferably 5 to 20 μ. If this thickness is 3 μm or less, the charge amount is insufficient, and if it is 50 μm or more, the residual potential is high and it is not practical.

The charge generation layer 15 is mainly composed of the disazo pigment represented by the above general formula, and may further contain a binder, a plasticizer and the like. The proportion of the disazo pigment in the charge generation layer is preferably 30% by weight or more, more preferably 50% by weight or more.

The charge transport layer 17 is mainly composed of a charge transport material and a binder, and may further contain a plasticizer and the like. The proportion of the charge carrier material in the charge carrier layer is 10 to 95% by weight, preferably 30 to 90%.
% By weight. If the proportion of the charge carrier material is less than 10% by weight, the charge carrier is hardly transferred, and
If it is more than 5% by weight, the mechanical strength of the photoreceptor film is extremely poor and it cannot be put to practical use.

In the case of the photoreceptor shown in FIG. 2, the thickness of the photosensitive layer 192 is preferably 3 to 50% by weight, more preferably 5 to 20 μm. The proportion of the disazo pigment in the photosensitive layer 192 is preferably 50% by weight or less, more preferably 20% by weight or less, and the proportion of the charge carrier substance is preferably 10 to 95% by weight, more preferably 30 to 90% by weight. % By weight.

The present invention is based on the use of the specific disazo pigment represented by the general formula (I) as the charge generating substance in the electrophotographic photosensitive member, and other components such as a conductive support and a charge carrier substance. Although any of the conventionally known components can be used, they will be specifically described below.

The conductive support used in the photoreceptor of the present invention includes a metal plate made of aluminum, copper, zinc or the like, a plastic sheet such as polyester or a plastic film deposited with a conductive material such as aluminum or SnO ₂ .
Alternatively, conductive treated paper or the like is used.

Examples of the binder include condensation resins such as polyamide, polyurethane, polyester, epoxy resin, polyketone, and polycarbonate, and vinyl polymers such as polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, and polyacrylamide. Any adhesive and adhesive resin can be used.

Examples of the plasticizer include halogenated paraffin, polychlorinated biphenyl, dimethylnaphthalene, dibutyl phthalate and the like. In addition, silicone oil or the like may be added to improve the surface property of the photoreceptor.

The charge carrier material includes a hole carrier material and an electron carrier material.
As the hole-transporting substance, for example, the following general formulas (1) to (1
Examples thereof include the compounds shown in 1).

(1) [In the formula, R ₁₁₅ represents a methyl group, an ethyl group, a 2-hydroxyethyl group or a 2-chloroethyl group, R ₁₂₅ represents a methyl group, an ethyl group, a benzyl group or a phenyl group, and R ₁₃₅ represents hydrogen or chlorine. , Bromine, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, a dialkylamino group or a nitro group. ] (2) [In the formula, Ar ₃ represents a naphthalene ring, an anthracene ring, a styryl group and a substitution product thereof, a pyridine ring, a furan ring or a thiophene ring, and R ₁₄₅ represents an alkyl group or a benzyl group. ] (3) [In the formula, R ₁₅₅ represents an alkyl group, a benzyl group, a phenyl group or a naphthyl group, and R ₁₆₅ represents hydrogen or a carbon number of 1 to 3
Represents an alkyl group, an alkoxy group having 1 to 3 carbon atoms, a dialkylamino group, a diaralkylamino group or a diarylamino group, n represents an integer of 1 to 4, and when n is 2 or more, R ₁₆₅ is the same. It may be different. R ₁₇₅ represents hydrogen or a methoxy group. 〕 (Four) [Wherein R ₁₈₅ represents an alkyl group having 1 to 11 carbon atoms, a substituted or unsubstituted phenyl group or a heterocyclic group, and R ₁₉₅
R ₂₀₅ may be the same or different and each represents hydrogen, an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group, a chloroalkyl group or a substituted or unsubstituted aralkyl group, and R ₁₉₅ and R ₂₀₅ are bonded to each other. It may form a heterocycle containing nitrogen. R ₂₁₅ may be the same or different and each represents hydrogen, an alkyl group having 1 to 4 carbon atoms, an alkoxy group or halogen. 〕 (Five) [In the formula, R ₂₂₅ represents a hydrogen atom or a halogen atom, and Ar _225
4 represents a substituted or unsubstituted phenyl group, naphthyl group, anthryl group or carzovalyl group. ] (6) [In the formula, R ₂₃₅ is hydrogen, halogen, a cyano group, and has 1 carbon atom.
Represents an alkoxy group having 4 to 4 or an alkyl group having 1 to 4 carbon atoms, and Ar ₅ is R ₂₄₅ represents an alkyl group having 1 to 4 carbon atoms,
R ₂₅₅ is hydrogen, halogen, an alkyl group having 1 to 4 carbon atoms,
Represents an alkoxy group having 1 to 4 carbon atoms or a dialkylamino group, n is 1 or 2, and when n is 2, R
₂₅₅ may be the same or different, and R ₂₆₅ and R ₂₇₅ represent hydrogen, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted benzyl group. ] (7) [Wherein R ₂₈₅ and R ₂₉₅ are a carbazolyl group, a pyridyl group, a cenyl group, an indolyl group, a furyl group or a substituted or unsubstituted phenyl group, a styryl group, a naphthyl group or an anthryl group, and these substituents Is selected from the group consisting of dialkylamino groups, alkyl groups, alkoxy groups, carboxy groups or esters thereof, halogen atoms, cyano groups, aralkylamino groups, N-alkyl-Naralkylamino groups, amino groups, nitro groups and acetylamino groups. Represents a radical ] (8) [In the formula, R ₃₀₅ represents a lower alkyl group or a benzyl group, and R ₃₁₅ represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a halogen atom, a nitro group, an amino group, or an amino group substituted with a lower alkyl group or a benzyl group. Represents a group, and n represents an integer of 1 or 2. ] (9) [Wherein, R ₃₂₅ represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, R ₃₃₅ and R ₃₄₅ represent an alkyl group, a substituted or unsubstituted aralkyl group or a substituted or unsubstituted aryl group, and R ₃₅₅ represents a hydrogen atom or a substituted or unsubstituted phenyl group, and Ar ₆ represents a phenyl group or a naphthyl group. 〕 (Ten) [In the formula, n is an integer of 0 or 1, R ₃₆₅ is a hydrogen atom, an alkyl group or a substituted or unsubstituted phenyl group, and A ₁ is Represents a 9-anthryl group or a substituted or unsubstituted N-alkylcarbazolyl group, wherein R ₃₇₅ is a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or (Wherein R ₃₈₅ and R ₃₉₅ represent an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, and R ₃₈₅ and R ₃₉₅ may form a ring), and m is 0, It is an integer of 1.2 or 3, and when m is 2 or more, R ₃₇₅ may be the same or different. ] (11) [In the formula, R ₄₀₅ , R ₄₁₅ and R ₄₂₅ represent hydrogen, a lower alkyl group, a lower alkoxy group, a dialkylamino group or a halogen atom, and n represents 0 or 1. Examples of the compound represented by the general formula (1) include 9-ethylcarbazole-3-aldehyde, 1-methyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde 1-benzyl-1-phenylhydrazone, 9- Such as ethylcarbazole-3-aldehyde 1,1-diphenylhydrazone.

Examples of the compound represented by the general formula (2) include 4-diethylaminostyrene-β-aldehyde 1-methyl-1-
Examples include phenylhydrazone and 4-methoxynaphthalene-1-aldehyde 1-benzyl-1-phenylhydrazone.

Examples of the compound represented by the general formula (3) include 4-methoxybenzaldehyde 1-methyl-1-phenylhydrazone, 2,4-dimethoxybenzaldehyde 1-benzyl-1-phenylhydrazone, 4-diethylaminobenzaldehyde 1,1-diphenyl. Hydrazone, 4-methoxybenzaldehyde 1-benzyl-1- (4-methoxy) phenylhydrazone, 4-diphenylaminobenzaldehyde 1-benzyl-1-phenylhydrazone, 4
-Dibenzylaminobenzaldehyde-1,1-diphenylhydrazone and the like.

Examples of the compound represented by the general formula (4) include 1,1-
Bis (4-dibenzylaminophenyl) propane, tris (4-diethylaminophenyl) methane, 1,1-bis (4-dibenzylaminophenyl) propane, 2,
2'dimethyl-4,4'-bis (diethylamino) -triphenylmethane and the like.

Examples of the compound represented by the general formula (5) include 9- (4
-Diethylaminostyryl) anthracene, 9-bromo-10- (4-diethylaminostyryl) anthracene and the like.

Examples of the compound represented by the general formula (6) include 9- (4
-Dimethylaminobenzylidene) fluorene, 3- (9
-Fluorenylidene) -9-ethylcarbazole and the like.

Examples of the compound represented by the general formula (7) include 1,2-
Bis (4-diethylaminostyryl) benzene, 1,2
-Bis (2,4-dimethoxystyryl) benzene.

Examples of the compound represented by the general formula (8) include 3-styryl-9-ethylcarbazole and 3- (4-methoxystyryl) -9-ethylcarbazole.

Examples of the compound represented by the general formula (9) include 4-diphenylaminostilbene, 4-dibenzylaminostilbene, 4-ditolylaminostilbene, 1- (4-diphenylaminostyryl) naphthalene, 1- (4-diethylamino). Styryl) naphthalene etc.

Examples of the compound represented by the general formula (10) include 4'-diphenylamino-α-phenylstilbene and 4'-methylphenylamino-α-phenylstilbene.

Examples of the compound represented by the general formula (11) include 1-phenyl-3- (4-diethylaminostyryl) -5- (4
-Diethylaminophenyl) pyrazoline, 1-phenyl-3- (4-dimethylaminostyryl) -5- (4-dimethylaminophenyl) pyrazoline and the like.

Other hole-transporting substances include, for example, 2,5-bis (4-diethylaminophenyl) -1,3,4-oxadiazole and 2,5-bis [4- (4-diethylaminostyryl) phenyl]-. 1,3,4-oxadiazole, 2- (9-ethylcarbazolyl-3-)-5- (4
-Diethylaminophenyl) -1,3,4-oxadiazole and other oxadiazole compounds, 2-vinyl-4
There are low molecular weight compounds such as oxadiazole compounds such as-(2-chlorophenyl) -5- (4-diethylaminophenyl) oxazole and 2- (4-diethylaminophenyl) -4-phenyloxazole. In addition,
Polymer compounds such as N-vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, pyreneformaldehyde resin, ethylcarbazoleformaldehyde resin can also be used.

Examples of the charge carrier substance include chloranil, bromanil, tetracyanoethylene, tetracyanoquinone dimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2, and the like. 4,5,7-Tetranitroxanthone, 2,
4,8-Trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophene-4
-One, 1,3,7-trinitrodibenzothiophene-
There are 5,5-dioxides.

These charge carrier substances may be used alone or in combination of two or more.

In each of the photoreceptors obtained as described above, an adhesive layer or a barrier layer may be provided between the conductive support and the photosensitive layer, if necessary. Polyamide, nitrocellulose, aluminum oxide and the like are suitable as materials used for these layers, and the film thickness is preferably 1 μm or less.

To prepare the photoconductor of FIG. 1, the disazo pigment on the conductive support is vacuum-deposited by the vacuum deposition method described in USP 3,973,959, USP 3,996,049, or fine particles of the disazo pigment are used. If necessary, disperse in a suitable solvent in which the binder is dissolved, apply this on a conductive support and dry,
Further, if necessary, a solution containing a charge carrier substance and a binder is prepared by surface finishing by a method such as buffing as disclosed in JP-A-51-90827 or after adjusting the film thickness. It is obtained by applying and drying.

To prepare the photoreceptor of FIG. 2, fine powder of disazo pigment may be dispersed in a solution in which a charge carrier substance and a binder are dissolved, and this may be coated and dried on a conductive support.

In any case, the disazo pigment used in the present invention is pulverized with a ball mill or the like to have a particle size of 5 μm or less, preferably 2 μm or less. The coating method is carried out by a conventional means such as doctor blade, dipping, wire bar or the like.

In order to perform copying using the photoreceptor of the present invention, the surface of the photosensitive layer is charged and exposed, and then developed, and if necessary,
This is achieved by transferring to paper or the like.

As is clear from the above description and the examples described below,
The electrophotographic photoreceptor of the present invention is easy to produce as compared with a conventional photoreceptor by using a disazo pigment having a benzophenone skeleton as a charge generating substance, and
The characteristics are stable even for repeated use of the photoconductor,
It has excellent properties.

Next, the present invention will be described in detail with reference to Examples, but the embodiments of the present invention are not limited thereto.

Example 1 76 parts by weight of disazo pigment No. 18; 1260 parts by weight of a polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.) in tetrahydrofuran solution (solid content concentration 2%); and tetrahydrofuran
3700 parts by weight are crushed and mixed in a ball mill, and the resulting dispersion is applied on the aluminum surface of an aluminum vapor-deposited polyester base (conductive support) using a doctor blade and air-dried to a thickness of about 1 μm. The charge generation layer of was formed.

On this charge generation layer, 2 parts by weight of 9-ethylcarbazole-3-aldehyde 1-methyl-1-phenylhydrazone as a charge carrier substance, 2 parts by weight of a polycarbonate resin (Panlite K-1300 manufactured by Teijin Ltd.) and tetrahydrofuran.
A solution prepared by mixing and dissolving 16 parts by weight was applied using a doctor blade and dried at 80 ° C. for 2 minutes and then at 105 ° C. for 5 minutes to form a charge transport layer having a thickness of about 20 μm, which is shown in FIG. A laminated type photoconductor No. 1 was prepared.

Examples 2-8 Instead of the disazo pigment No. 18 used in Example 1, the following table-
Photoreceptor Nos. 2 to 8 were prepared in the same manner as in Example 1 except that the disazo pigment shown in 1 was used.

Examples 9 to 12 Example 1 except that 1-phenyl-3- (4-diethylaminostyryl) -5- (4-diethylaminophenyl) pyrazoline was used as the charge carrier substance and the disazo pigment shown in Table 2 below was used. Photoreceptor Nos. 9 to 12 in the same manner as
It was created.

Examples 13 to 20 Photoreceptor Nos. 13 to 20 were carried out in the same manner as in Example 1 except that 4'-diphenylamino-α-phenylstilbene was used as the charge carrier and the disazo pigments shown in Table 3 below were used.
It was created.

For these photoconductors No. 1 to 20, using an electrostatic copying paper test device (SP428 type manufactured by Kawaguchi Electric Co., Ltd.),
After corona discharge of -6KV for 20 seconds to make it negatively charged, leave it in the dark for 20 seconds, and then surface potential V _po (V)
Then, a tungsten lamp is used to irradiate the surface with light having an illuminance of 4.5 lux, and the time (second) until the surface potential becomes 1/2 V _po is obtained. (Looks / second) was calculated. The results are shown in Table-1 to Table-3.

Effect From the results shown in Tables 1 to 3 above, it can be seen that the photoreceptor of the present invention has high sensitivity.

Further, the photoconductors No. 16 and No. 19 of the present invention were mounted on a Ricoh Copier Recopy P-500 model to produce an image of 10,000.
As a result, a clear image was obtained without changing any of the photoreceptors by repeating the copying process. From this, it can be understood that the photoreceptor of the present invention is also excellent in durability.

[Brief description of drawings]

1 and 2 are enlarged cross-sectional views showing a structural example of the green light body of the present invention. FIG. 3 shows the disazo pigment used in the present invention.
It is the infrared absorption spectrum of No. 1 (KBr tablet method). 11 ... Conductive support, 13 ... Disazo pigment 15 ... Charge generation layer, 17 ... Charge transport layer 191,192 '... Photosensitive layer

Claims (1)

[Claims] 1. A compound of general formula (I) on a conductive support. (In the formula, A represents a coupler residue) A photoconductor for electrophotography, characterized in that a layer containing a disazo pigment represented by the formula as an active ingredient is formed.