JPH0640222B2 - 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. A typical example is one 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, be careful when handling. 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, and abrasion resistance are low. Since it has mechanical defects such as properties, it is often problematic in terms of durability as a photoreceptor for a plain paper copying machine that is repeatedly used. 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 photoconductor of No. 1), it is generally noted as a photoconductor for a plain paper copying machine because of its high sensitivity and stable charging property, and some of them have been put to practical use.

This type of conventional laminated type photoreceptor, (1) using a thin layer obtained by vacuum-depositing a perylene derivative as a charge generation layer and using an oxadiazole derivative as a charge transport layer (see usp 3871882) (2) A thin layer formed by applying an organic amine solution of chlordian blue is used as the charge generation layer, and a hydrazone compound is used as the charge transport layer (see Japanese Patent Publication No. 55-42380). (3) Di charge generation layer Using a thin layer formed by applying an organic solvent dispersion of a styrylbenzene-based disazo compound,
Using a hydrazone compound in the charge transport layer
5-84943 gazette) etc. are known.

However, it is also true that the conventional type of laminated type photoconductor has many advantages as well as various drawbacks. That is, it has the following drawbacks.

The photoconductor 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 photoconductor using chlordian blue and the hydrazone compound shown in (2) requires the use of an organic amine (e.g. 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 light wavelength range extends from approximately 450 to 660 nm, the image reproducibility of the red original is poor. Therefore, when it is 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 because a charge generation layer can be easily formed by coating a dispersion of the disazo compound. As in the case of the photoconductor of (2), the photosensitivity wavelength range extends from 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 Kuppler residue.) By the way, in view of the above-mentioned conventional drawbacks, the present inventor can easily manufacture and has high sensitivity, and the photosensitive wavelength region is in the short wavelength region (that is, in the red original document). As a result of extensive studies aimed at developing an electrophotographic photosensitive member (having excellent image reproducibility), the use of the specific disazo compound represented by the general formula (I) as a charge-generating substance resulted in the above-mentioned object. The present invention has been completed based on the finding that the above can be achieved.

As the kuppler in the general formula (I), for example, phenols, compounds having a phenolic hydroxyl group such as naphthols, aromatic amino compounds having an amino group,
Alternatively, aminonaphthols having an amino group and a phenolic hydroxyl group, a compound having an aliphatic or aromatic phenolic ketone group (active methylene group), and the like are used. Preferably, the cutler residue A has the following general formula (I). ,
(II), (III), (IV), (V), (VI), (VII), (VIII), (I
It is represented by the general formulas (X), (X), (XI), and (XII).

[In the above formulas (II), (III), (IV) and (V), X, Y ₁ , Z,
m and n respectively represent the following.

X: -OH, Or —NHSO ₂ —R ₃ (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 (However, R ₅ represents a hydrocarbon ring group or a substituted product thereof, a heterocyclic group or a substituted product thereof, or 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 formulas (VI) and (VII), R ₇ represents a substituted or unsubstituted hydrocarbon group, 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 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, benzofuran 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 thienyl group, a furyl group, an indolyl group, a benzofuranyl group, or a carbazolyl group. Group, a dibenzofuranyl group, and the like, and examples of the ring formed by combining R ₅ and R ₆ include a fluorene ring and the like.

Examples of the substituent on the hydrocarbon ring group or heterocyclic group of Y ₂ or R ₅ or the ring formed by R ₅ and R ₆ include
Alkyl groups such as methyl group, ethyl group, propyl group, butyl group, alkoxy groups such as methoxy group, ethoxy group, propoxy group, butoxy group, halogen atoms such as chlorine atom, bromine atom, dimethylamino group, diethylamino group, etc. Dialkylamino group, diaralkylamino group such as dibenzylamino group, halomethyl group such as trifluoromethyl group, nitro group, cyano group, erboxyl group or its ester, hydroxyl group, sulfonate group such as -SO ₃ Na, etc. To be

A halogen atom such as a chlorine atom or a bromine atom can be exemplified as the substituent of the phenyl group of R ₄ .

Representative examples of the hydrocarbon group for 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 aryl group such as an aralkyl group such as a benzyl group, and a substituted product thereof. it can.

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

Representative examples of the hydrocarbon ring group in 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, a propyl group, a butyl group and the like. Examples thereof include alkyl groups, methoxy groups, ethoxy groups, propoxy groups, butoxy groups and other alkoxy groups, nitro groups, halogen atoms such as chlorine and bromine atoms, cyano groups, dimethylamino groups, and dialkylamino groups such as diethylamino groups. .

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

Among the above-mentioned Kupler residues, 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 Kuppler residue represented by (Z, Y ₂ and R ₂ are the same as above.).

Furthermore, among the above-mentioned preferred Kupler residues, the general formula (XIII) or (XIV) (Z, R ₂ , R ₅ and R ₆ are the same as those described above, and R ₁₀ is preferably the substituent of Y ₂ above.).

Specific examples of the disazo pigment used in the present invention as described above are shown by the structural formulas as follows. For simplification, only the structural formula of A, which is a Kuppler residue, is shown.

By using the disazo pigment of the present invention as described above, an extremely high-sensitivity electrophotographic photoreceptor can be easily produced. Among them, particularly preferable disazo pigments as charge generating substances are Nos. 14, 17, 20, 23, 26,29,58,84,90.

The disazo pigment of the present invention is prepared by a conventional method, for example, 3,6-bis (4-aminophenyl) -S-tetrazine produced by the method described in Kenzo Konishi et al., Journal of Chemical Society of Japan 1973 , 319 (1973). It can be easily produced by diazotizing to give a tetrazonium salt, and subjecting the tetrazonium salt and the corresponding cuppler to a coupling reaction by reacting a base in a suitable organic solvent such as N, N-dimethylformamide. As an example, the production example of the above-mentioned No. 1 disazo pigment will be shown below, but other disazo pigments can be easily produced according to this production example except that the cup puller is changed.

Preparation Example 3,6-bi-diamine was added to hydrochloric acid consisting of 79 ml of water and 79 ml of concentrated hydrochloric acid.
Add 22.8 g of su (4-aminophenyl) -S-tetrazine
Eh, after heating to about 60 ℃ for 1 hour, until -3 ℃
Cool and then add 13.1 g of sodium nitrite to 3 parts of water.
The solution dissolved in 0 ml was heated at a temperature of -3 ° C to 0 ° C for 50 minutes.
Dropped over. Then, after stirring at the same temperature for 30 minutes,
To this reaction liquid, add 120 ml of 42% borofluoric acid.
Then, the precipitated crystals are separated, washed with water and dried to give 31.38 g.
(Yield 78.8%) tetrazonium, difluoroborate
Red crystals were obtained. Decomposition point 106 ℃ or above, infrared absorption
2280 cm for the vector (KBr tablet method)^-1To N_Two Based on
An absorption band was observed.

4.6 g of the tetrazonium salt thus obtained and 5.8 g of 2-hydroxy-3-naphthoic acid anilide (twice the mole of the tetrazonium salt) as a coupling component were added to 700 ml of cooled N, N-dimethylformamide. Dissolve in this, 2.5 g of sodium acetate and 25 ml of water
The resulting solution was added dropwise at a temperature of 5 to 10 ° C. over 20 minutes, cooling was stopped, and the formed precipitate was removed.
N, N-dimethylformamide 700 heated to 0 ° C
Wash 3 times with ml, then twice with 700 ml of water, 80 ° C
And dried under reduced pressure of 2 mmHg to obtain 5.6 g (yield 68.9%) of the above-mentioned compound No. 1 disazo pigment. The appearance of this disazo pigment is red powder, and the infrared absorption spectrum (KBr tablet method) is shown in FIG.

Melting point 300 ° C or more 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 of FIG. 1 is a laminated type photosensitive layer 19 including a charge generating layer 15 mainly containing a disazo pigment 13 and a charge transporting layer 17 mainly containing a charge transporting substance on a conductive support 11.
1 is provided.

In the photoreceptor of FIG. 1, the image-exposed light passes through the charge transport layer and reaches the charge generation layer 15, and the disazo pigment 13 in that portion generates charge, while the charge transport layer 17 charges the charge. Is carried out, and the charge is carried by the disazo pigment 13, and the charge is carried by the charge carrying layer 17.

The photoconductor of FIG. 2 comprises a conductive support 11 and a photosensitive layer 192 which is mainly composed of 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 photosensitive member, the charge generation layer and the charge transport layer shown in FIG. 1 can 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, and more preferably 5 to 20 μ. This thickness is 3
When it is less than μ, the charge amount is insufficient, and when it is more than 50 μ, 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 substance in the charge carrier layer is 10 to 95% by weight, preferably 30 to 90% by weight. If the proportion of the charge carrier substance is less than 10% by weight, the charge is hardly transported, and if it exceeds 95% 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 μ, more preferably 5 to 20 μ. The proportion of the disazo pigment in the photosensitive layer 192 is preferably 50% by weight or less, more preferably 20% by weight.
And the proportion of charge carrier material is preferably 10
˜95% by weight, more preferably 30 to 90% 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.

As the conductive support used in the photoreceptor of the present invention, aluminum, copper, a metal plate such as zinc, a plastic sheet such as polyester or a plastic film aluminum, a conductive material such as SnO ₂ is vapor-deposited, or conductive. Treated paper 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 biphenyls, 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 ₁₁ represents a methyl group, an ethyl group, a 2-hydroxyethyl group or a 2-chloroethyl group, and R ₁₂ represents a methyl group, an ethyl group, a benzyl group or a phenyl group, and R
₁₃ represents hydrogen, 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 substituted product thereof, a pyridine ring, a furan ring or a thiophen ring, and R ₁₄ represents an alkyl group or a benzyl group. ] (3) [In the formula, R ₁₅ is an alkyl group, a benzyl group, a phenyl group,
Represents a naphthyl group, R ₁₆ represents hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a dialkylamino group, a diaralkylamino group or a diarylamino group, and n is 1 to 4 It represents an integer, and when n is 2 or more, R ₁₆ may be the same or different. R ₁₇ represents hydrogen or a methoxy group. 〕 (Four) [In the formula, R ₁₈ represents an alkyl group having 1 to 11 carbon atoms, a substituted or unsubstituted phenyl group or a heterocyclic group, and R ₁₉ , R
₂₀ 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, a substituted or unsubstituted aralkyl group, and R ₁₉ and R ₂₀ are bonded to each other. And may form a heterocycle containing nitrogen. R ₂₁ 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 ₂₂ represents hydrogen or a halogen atom, and Ar ₄ represents a substituted or unsubstituted phenyl group, naphthyl group, anthryl group or carbazolyl group. ] (6) [In the formula, R ₂₃ is hydrogen, halogen, cyano group, carbon number 1 to 4
Represents an alkoxy group or an alkyl group having 1 to 4 carbon atoms, and Ar ₅ is Or R ₂₄ represents an alkyl group having 1 to 4 carbon atoms, R _24
25 represents hydrogen, halogen, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a dialkylamino group, n is 1 or 2, and when n is 2, R ₂₅ is the same. R ₂₆ and R ₂₇ may be different and each represents hydrogen, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms or a substituted or unsubstituted benzyl group. ] (7) [In the formula, R ₂₈ and R ₂₉ are a carbazolyl group, a pyridyl group, a thienyl group, an indolyl group, a phenyl group or a substituted or unsubstituted phenyl group, a styryl group, a naphthyl group or an anthryl group, and these substituents are 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 ₃₀ represents a lower alkyl group or a benzyl group, R ₃₁ represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a halogen atom, a nitro group, an amino group, or an amino substituted with a lower alkyl group or a benzyl group. Represents a group, and n represents an integer of 1 or 2. ] (9) [In the formula, R ₃₂ represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, R ₃₃ and R ₃₄ represent an alkyl group, a substituted or unsubstituted aralkyl group or a substituted or unsubstituted aryl group, and R ₃₅ 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 ₃₆ represents a hydrogen atom, an alkyl group or a substituted or unsubstituted phenyl group,
A ₁ is Represents a 9-anthryl group or a substituted or unsubstituted N-alkylcarbazolyl group, wherein R ₃₇ represents a hydrogen atom,
Alkyl group, alkoxy group, halogen atom or (Wherein R ₃₈ and R ₃₉ represent an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, and R ₃₈ and R ₃₉ may form a ring), and m
Is an integer of 0, 1, 2, or 3, and when m is 2 or more, R ₃₇ may be the same or different. ] (11) [Wherein R ₄₀ , R ₄₁ and R ₄₂ are hydrogen, a lower alkyl group,
It represents 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-ethylcarbazole-3-aldehyde 1,1-diphenylhydrazone and the like.

Examples of the compound represented by the general formula (2) include 4-diethylaminostyrene-β-aldehyde 1-methyl-1-
Examples thereof 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. -Diphenylhydrazone, 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)-
Examples include triphenylmethane.

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 -Diethylaminostyryl) naphthalene and the like.

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

The compound represented by the general formula (11) includes, for example, 1-phenyl-3- (4-diethylaminostyryl) -5- (4
-Diethylaminophenyl) pyrazolin, 1-phenyl-3- (4-dimethylaminostyryl) -5- (4-dimethylaminophenyl) pyrazolin and the like.

Examples of other hole-transporting substances include 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-
Oxadiazole compounds such as diethylaminophenyl) -1,3,4-oxadiazole, 2-vinyl-4-
There are low molecular compounds such as (2-chlorophenyl) -5- (4-diethylaminophenyl) oxazole and 2- (4-diethylaminophenyl) -4-phenyloxazole. In addition, poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene,
Polymer compounds such as pyrene formaldehyde resin and ethylcarbazole formaldehyde resin can also be used.

Examples of the electron carrier substance include chloranil, bromanil, tetracyanoethylene, tetracyanoquinone dimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2, 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 photoreceptor of FIG. 1, a disazo pigment is vacuum-deposited on the conductive support 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 development is carried out.
This is achieved by transferring to paper or the like.

As is clear from the above description and Examples and Comparative Examples described below, the electrophotographic photoreceptor of the present invention uses the disazo pigment having a 3,6-diphenyl-S-tetrazine skeleton as a charge-generating substance. It is easier to manufacture than conventional photoconductors, has high sensitivity, and has a photosensitive wavelength range in the short wavelength range (450 to 600 nm), and its characteristics are stable even when used repeatedly. It has excellent properties such as

Next, the present invention will be specifically described with reference to examples, but the embodiments of the present invention are not limited thereby.

Example 1 76 parts by weight of disazo pigment No. 1, 1260 parts by weight of a polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.) in tetrahydrofuran (solid content concentration 2%), and 3700 parts by weight of tetrahydrofuran were pulverized and mixed in a ball mill, The obtained dispersion liquid was applied onto an aluminum surface of an aluminum-deposited polyester base (conductive support) using a doctor blade and naturally dried to form a charge generation layer having a thickness of about 1 μm.

On this charge generating layer, 2 parts by weight of 9-ethylcarbazole-3-aldehyde 1-methyl-1-phenylhydrazone as a charge carrier, 2 parts by weight of a polycarbonate resin (Panlite K-1300 manufactured by Teijin Ltd.) and 16 parts of tetrahydrofuran. A solution obtained by mixing and dissolving 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 to 25 The following table is shown instead of the disazo pigment No. 1 used in Example 1.
Photoreceptor Nos. 2 to 25 were prepared in the same manner as in Example 1 except that the disazo pigment shown in 1 was used.

Examples 26 to 40 Examples 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. Photoconductor No. 26-
40 was created.

Examples 41 to 55 Photoreceptor No. 41 was carried out in the same manner as in Example 1 except that 9- (4-diethylaminostyryl) anthracene was used as the charge carrier substance and the disazo pigment shown in Table 3 below was used.
~ 55 was created.

Examples 56 to 60 Photosensitive members were prepared in the same manner as in Example 1 except that 1,1-bis (4-dibenzylaminophenyl) propane was used as the charge carrier substance and the disazo pigment shown in Table 4 below was used. N
o.56-60 were created.

About these photoconductors No. 1 to 60, 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 Vpo (V)
Then, a tungsten lamp is used to illuminate the surface so that the illuminance is 4.5 lux, and the time (seconds) until the surface potential becomes 1/2 of Vpo is obtained. 2 (lux / sec) was calculated. The results are shown in Table-1 to Table-4.

Comparative Example 1 A laminated type photoreceptor was prepared as described in USP3871882 in which the perylene derivative was used as the charge generation layer and the oxadiazole derivative was used as the charge transport layer as follows.

N, N′-dimethylperylene-3 as a charge generating substance,
4,9,10-Tetracarboxylic acid diimide was vacuum-deposited on an aluminum plate under the conditions of a vacuum degree of 10 ⁻⁵ mmHg, an evaporation source temperature of 350 ° C., and an evaporation time of 3 minutes to form a charge generation layer. Then, on this charge generating layer, 5 parts by weight of 2,5-bis (4-diethylaminophenyl) -1,3,4-oxadiazole and 5 parts by weight of a polyester resin (Polyester Adhesive 49000 manufactured by Dyupon) are used. And 90 parts by weight of tetrahydrofuran were applied and dried at 120 ° C. for 10 minutes to form a charge carrying layer having a thickness of about 10 μm, and comparative photoconductor No. 1 was prepared.

Comparative Example 2 A laminated type photoreceptor described in JP-B-55-42380 was prepared in the following manner using chlordian blue as the charge generation layer and a hydrazone compound in the charge transport layer.

Chlordian blue 25 parts by weight, ethylenediamine 12
A solution of 40 parts by weight, 990 parts by weight of n-butylamine and 2740 parts by weight of tetrahydrofuran was applied onto an aluminum surface of an aluminum-deposited polyester base with a wet gear 25 μm using a doctor blade and dried to form a charge generation layer. Then, on this charge generation layer, 4
A solution of 10 parts by weight of diethylaminobenzaldehyde-1,1-diphenylhydrazone, 10 parts by weight of a polycarbonate resin (the same as the resin used in Example 1) and 80 parts by weight of tetrahydrofuran was applied using a doctor blade, A charge carrying layer having a thickness of about 18 μm was formed by drying to prepare a laminated type comparative photoconductor No. 2.

Comparative Example 3 A distyrylbenzene-based disazo compound described in JP-A-55-84943 is used as a charge generation layer.
A laminated type photoreceptor using a hydrazone compound for the charge transport layer was prepared as follows.

4 ', 4 "-bis [2-hydroxy-3- (2,4-dimethylphenylcarbamoyl) -1-naphthylazo]-
1,4-Distyrylbenzene 20 parts by weight, polyvinyl butyral (Tokyo Denki Kagaku KK Denka Butyral # 4000-
1) 3 parts by weight, 7 parts by weight of polymethylmethacrylate (Dianal BR-80 manufactured by Mitsubishi Rayon Co., Ltd.) and 300 parts by weight of tetrahydrofuran were milled for 3 hours in a ball mill, and this dispersion was diluted with 2700 parts by weight of tetrahydrofuran. Then, it was applied on the aluminum surface of the aluminum-deposited polyester base (conductive support) using a doctor blade and dried to form a charge generation layer having a thickness of about 0.3 μm. Then, 10 parts by weight of 9-ethylcarbazole-3-aldehyde 1-methyl-1-phenylhydrazone and a polycarbonate resin (Example 1
10 parts by weight of the same resin as used in (1) and 80 parts by weight of tetrahydrofuran are applied using a doctor blade and dried to form a charge carrying layer having a thickness of about 13 μm. No.3 was created.

These comparative photoconductors Nos. 1 to 3 and the photoconductor No. 4 of the present invention
For No. 7 and No. 7, the spectral sensitivity was measured by the following measurement procedure in order to investigate the photosensitive wavelength range.

First, the surface potential of the photoconductor is charged to -800 V or more by corona discharge in the dark, and the surface potential is -800 V.
The film was dark-attenuated until it reached a voltage of volt, and when the surface potential reached -800 volts, the photoconductor was irradiated with monochromatic light having an intensity of 1 μW / cm ² on the photoconductor surface, which was separated by a monochromator. Then, the time (seconds) until the surface potential decays to -400 V is obtained, and the half-exposure amount (μW · sec / cm ² )
Was calculated. On the other hand, the potential difference actually obtained by exposure is calculated by subtracting the potential attenuation due to dark decay from the apparent potential difference of 400 V obtained by exposure, and the light decay rate is calculated from this potential difference and the half-exposure amount. (Volt ・ cm ²
・ ΜW ^-1 · sec ^-1 ) was calculated as the sensitivity. The spectral sensitivities thus obtained are shown in FIGS.

FIG. 4 ... Photoconductor No. 4 of the present invention FIG. 5 ... Photoconductor No. 7 of the present invention FIG. 6 ... Comparative photoconductor Nos. 1, 2, and 3 Effects Tables 1 to 4 and 4 From the results of FIGS. 6 to 6, it can be seen that the photoconductor of the present invention has high sensitivity, and the photosensitizing wavelength range is about 460 to 600 nm.

Further, the photoconductors No. 4 and No. 7 of the present invention were mounted on a copying machine Recopy P-500 type manufactured by Ricoh Co., Ltd. to produce an image of 10,0.
Repeated 00 times, as a result, a clear image was obtained without any change in the photoreceptor due to repeated 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 constitutional example of the photoconductor 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). 4 to 6 are graphs showing the spectral sensitivity characteristics of the photoconductor of the present invention and the comparative photoconductor. 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. An electrophotographic photoreceptor comprising a disazo pigment represented by the formula (wherein A represents a Kuppler residue) as an active ingredient.