JPH0422265B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a photoreceptor for electrophotography, and more particularly, the present invention relates to a photoreceptor for electrophotography, and more specifically, the present invention relates to a photoreceptor for electrophotography, which is provided with a photosensitive layer containing a disazo pigment as a substance that generates charge carriers when irradiated with light (hereinafter referred to as a charge-generating substance). Regarding the body. The present invention relates to a photoreceptor for electrophotography, and more specifically, a layer containing a substance (hereinafter referred to as a charge-generating substance) that generates charge carriers when irradiated with light (hereinafter referred to as a charge-generating substance).
This is called the charge generation layer. ) and the charge generation layer accepts the generated charge carriers and transports them (hereinafter referred to as
It is called a charge transport material. ) (hereinafter referred to as a charge transport layer). Conventionally, there have been inorganic photoreceptors for electrophotography, such as those using selenium and its alloys, or photoreceptors with dye-sensitized zinc oxide dispersed in a binder resin, and organic photoreceptors. So,
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). be. but,
Although these photoreceptors have many advantages, it is also true that they also have various disadvantages. For example, the currently widely used selenium photoreceptor has difficult manufacturing conditions and high manufacturing costs, is difficult to process into a belt shape due to its lack of flexibility, and is sensitive to heat and mechanical shock. Therefore, care must be taken when handling it. Zinc oxide photoreceptors are low in cost because they can be manufactured by applying inexpensive zinc oxide to a support, but they generally have low sensitivity, poor surface smoothness, hardness, tensile strength, and durability. It has mechanical drawbacks such as friction,
As a photoreceptor for a plain paper copying machine, which is normally used repeatedly, there are many problems such as durability. Also, TNF and
Photoreceptors using PVK charge transfer complexes have low sensitivity and are unsuitable as photoreceptors for high-speed copying machines. In recent years, extensive research has been carried out to eliminate the drawbacks of these photoreceptors, and in particular, various organic photoreceptors have been proposed. Among them, a laminated photoreceptor in which a thin film of an organic pigment is formed on a conductive support (charge generation layer) and a layer mainly composed of a charge transport substance (charge transport layer) is formed, which is different from conventional organic-based photoreceptors. Compared to photoconductors, photoconductors are attracting attention as photoconductors for plain paper copying machines because they generally have higher sensitivity and stable charging properties, and some of them are in practical use. Conventional laminated photoreceptors of this type include: (1) one in which a thin layer of a perylene derivative vacuum-deposited is used as a charge generation layer and an oxadiazole derivative is used as a charge transport layer (see U.S. Pat. No. 3,871,882); ), (2) Using a thin layer formed by coating an organic amine solution of chlordiane blue as the charge generation layer,
(3) A thin layer formed by coating an organic solvent dispersion of a distyrylbenzene-based disazo compound as a charge generation layer, One in which a hydrazone compound is used in the charge transport layer (see Japanese Unexamined Patent Publication No. 84943/1983) is known. However, it is true that conventional laminated photoreceptors of this type have many advantages, but also have various drawbacks. The photoreceptor using the perylene derivative and oxadiazole derivative shown in (1) has a charge generation layer formed by vacuum evaporation, which increases the manufacturing cost. The photoconductor using chlordiane blue and 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 to form the charge generation layer, which makes it difficult to fabricate the photoconductor. There are many shortcomings. Also,
Since the photosensitive wavelength range in the visible range extends from approximately 450 to 660 nm, the image reproducibility of red originals was poor. Therefore, when actually implemented in a copying machine, a filter is required to cut out red light, which is disadvantageous in the design of the copying machine. The photoreceptor using a distyrylbenzene-based disazo compound and a hydrazone compound shown in (3) is very advantageous in terms of manufacturing because a charge generation layer can be easily formed by coating a dispersion of the disazo compound. , (2), its sensitive wavelength range extends from approximately 450 to 700 nm, so it has the disadvantage of poor image reproducibility for red originals. In view of the above points, the present inventor has developed a product that is easy to manufacture, has high sensitivity, and has a sensitive wavelength range in the short wavelength range (that is, has excellent image reproducibility for red originals).
As a result of intensive studies aimed at developing a photoreceptor for electrophotography, the inventors discovered that the above object could be achieved by using a certain disazo compound as a charge generating substance, and thus completed the present invention. . That is, the electrophotographic photoreceptor of the present invention is characterized in that a photosensitive layer containing a disazo pigment represented by the following general formula () as a charge generating substance is provided on a conductive support. (In the formula, A represents a coupler residue.) Examples of the coupler include compounds having a phenolic hydroxyl group such as phenols and naphthols, aromatic amino compounds having an amino group, or combinations of an amino group and a phenolic hydroxyl group. compounds having an aliphatic or aromatic enolic ketone group (active methylene group), etc. are used, preferably, the coupler residue A has the following general formula (), (), (), () ,
(), (), (), (), (), () (XI
),
It is represented by the general formula (XII). [In the above formulas (), (), () and (),
X, Y ₁ , Z, m and n each represent the following. X:-OH,

[Formula] or -NHSO ₂ - R ₃ (R ₁ and R ₂ represent hydrogen or substituted or unsubstituted alkyl, 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

[Formula] (R ₄ represents hydrogen, an alkyl group or a substituent thereof, a phenyl group or a substituent thereof, Y ₂ represents a hydrocarbon ring group or a substituent thereof,
a heterocyclic group or a substituent thereof, or

[Formula] (However, R ₅ represents a hydrocarbon ring group or a substituent thereof, a heterocyclic group or a substituent thereof, a styryl group or a substituent thereof, and R ₆ represents hydrogen, an alkyl group, a phenyl group, or a substituent thereof. ,or
R ₅ and R ₆ may form a ring together with the carbon atoms bonded to them. ) is shown. ) Z: hydrocarbon ring or its substituent, or heterocycle or its substituent n: an integer of 1 or 2 m: an integer of 1 or 2] [In formulas () and (), R ₇ represents a substituted or unsubstituted hydrocarbon group, and X is as defined above. ] [In the formula, R ₈ is an alkyl group, a carbamoyl group,
represents a carboxyl group or its ester,
Ar ₁ represents a hydrocarbon ring group or a substituent thereof,
X is the same as above. ] [In the above formulas () and (), R ₉ represents hydrogen or a substituted or unsubstituted hydrocarbon group,
Ar ₂ represents a hydrocarbon ring group or a substituted product thereof. ] Examples of the hydrocarbon ring of Z in the general formula (), () or () include a benzene ring and a naphthalene ring, and examples of the heterocycle include an indole ring, a carbazole ring, a benzofuran ring, and a benzofuran ring. can. Furthermore, examples of substituents on the ring of Z include halogen atoms such as chlorine atoms and bromine atoms. As the hydrocarbon ring group in Y ₂ or R ₅ ,
Examples of the heterocyclic group include a phenyl group, a naphthyl group, an anthryl group, a pyrenyl group, and a pyridyl group, a thienyl group, a furyl group, an indolyl group, a benzofuranyl group, a carbazolyl group, a dibenzofuranyl group, and the like. Examples of the ring formed by combining R ₅ and R ₆ include a fluorene ring. Substituents on the carbocyclic 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, ethyl, propyl, and butyl groups, and methoxy groups. , alkoxy groups such as ethoxy, propoxy, and butoxy groups, halogen atoms such as chlorine and bromine, dialkylamino groups such as dimethylamino and diethylamino groups, dialkylamino groups such as dibenzylamino, trifluoromethyl groups such as halomethyl group, nitro group, cyano group, carboxyl group or its ester, hydroxyl group, -SO ₃ Na
Examples include sulfonic acid groups such as. Examples of substituents for the phenyl group of R ₄ include halogen atoms such as chlorine atoms and bromine atoms. Typical examples of the hydrocarbon group in R ₇ or R ₉ include alkyl groups such as methyl, ethyl, propyl, and butyl, aralkyl groups such as benzyl, aryl groups such as phenyl, or substituents thereof. I can give an example. Substituents on the hydrocarbon group of R ₇ or R ₉ include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, methoxy group, ethoxy group,
Alkoxy groups such as propoxy groups and butoxy groups,
Examples include halogen atoms such as chlorine atoms and bromine atoms, hydroxyl groups, and nitro groups. As the hydrocarbon ring group in Ar ₁ or Ar ₂ ,
Representative examples include phenyl group and naphthyl group, and substituents for these groups 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 nitro group, chlorine atom, bromine atom, cyano group, dimethylamino group and dialkylamino groups such as diethylamino groups. Furthermore, among X, a hydroxyl group is particularly suitable. Among the above coupler residues, those represented by the above general formulas (), (), (), (), () and () are preferred, and among these, those in which X in the general formula is a hydroxyl group are preferred. Also, among these, the general formula (′) (Y ₁ and Z are the same as above.) A coupler residue represented by the following is preferable, and more preferably a coupler residue represented by the general formula (Z, Y ₂ and R ₂ are the same as above.) This is a coupler residue represented by. Furthermore, among the above preferred coupler residues, general formula (XI) or () (Z, R ₂ , R ₅ and R ₆ are the same as above,
Furthermore, examples of R ₁₀ include the above Y ₂ substituent. ) is appropriate. Specific examples of the disazo pigment used in the present invention as described above are shown in the following structural formula. For simplicity, only the structural formula of A, which is a coupler residue, is shown.

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[Table] By using the disazo pigment of the present invention as described above, an extremely sensitive electrophotographic photoreceptor can be easily manufactured.Among these, particularly preferable disazo pigments as charge generating substances are Nos. 14, 17, and 20. ,twenty three,
26, 29, 58, 84, 90. The disazo pigment of the present invention is, for example, AA
Goldberg and H.A.Walker, Journal of
Chemieal Society, 1953, 1348 (1953), 2,7-diaminoxanthone was prepared by diazotization using a conventional method to obtain a tetrazonium salt, and the tetrazonium salt and the corresponding coupler were mixed in a suitable organic solvent, For example, N, N-
It can be easily produced by coupling reaction with a base in dimethylformamide. As an example, the production example of disazo pigment No. 1 is shown below, but other disazo pigments can also be easily produced according to this production example, except for changing the coupler. Production example 2,
Add 29.18g of 7-diaminoxanthone and heat to approximately 60°C.
After heating for 1 hour, cool to -3℃,
Next, a solution of 18.7 g of sodium nitrite dissolved in 90 ml of water was added dropwise to this at a temperature of -3°C to 0°C over 50 minutes. After stirring at the same temperature for 30 minutes, 150 ml of 42% borohydrofluoric acid was added to the reaction solution, and the precipitated crystals were separated, washed with water, and dried.
47.13 g (yield 86.1%) of pale yellow crystals of tetrazonium difluoroborate were obtained. Decomposition point 145℃
As mentioned above, in the infrared absorption spectrum (KBr tablet method), there is an absorption band based on N ₂ at 2280 cm ^-1 and 1685 cm ^-1
An absorption band based on C=O was observed. Tetrazonium salt thus obtained 5.0
g and 2-hydroxy-3 as a coupling component.
- Dissolve 6.25 g of naphthoic acid anilide (twice the mole of the tetrazonium salt) in 700 ml of cooled N,N-dimethylformamide, and add a solution consisting of 4.0 g of sodium acetate and 35 ml of water at 5 to 10°C.
The mixture was added dropwise over a period of 20 minutes at a temperature of 100 mL, and after cooling was discontinued, the mixture was further stirred at room temperature for 3 hours. Thereafter, the formed precipitate was collected and washed three times with 700 ml of N,N-dimethylformamide heated to 80°C, and then washed with water.
Washed twice with 700 ml and dried at 80°C under a vacuum of 2 mmHg to obtain 8.2 g of disazo pigment of Compound No. 1 in Table 1.
(yield 90.0%). This disazo pigment appeared as a red powder, and its infrared absorption spectrum (KBr tablet method) was shown in FIG. Melting point 300°C or higher Elemental analysis value (%) Calculated value Actual value C 72.86 72.61 H 3.91 3.88 N 10.84 10.77 In the electrophotographic photoreceptor of the present invention, the disazo pigment is used as a charge generating substance in the photosensitive layer, and the disazo pigment is used as a charge generating substance in the photosensitive layer. Typical configurations are shown in FIGS. 2 and 3. The photoreceptor shown in FIG. 2 has a laminated photosensitive layer 19 on a conductive support 11, which is composed of a charge generation layer 15 mainly composed of a disazo pigment 13 and a charge transport layer 17 mainly composed of a charge transport substance. It is something that In the photoreceptor shown in FIG. 2, the imagewise exposed light passes through the charge transport layer and reaches the charge generation layer 15, where the disazo pigment 13 generates a charge, while the charge transport layer 17 The mechanism is such that the disazo pigment 13 generates the charge necessary for light attenuation, and the charge transport layer 17 transports the charge. The photoreceptor shown in FIG. 3 has a photosensitive layer 19 mainly composed of a disazo pigment 13, a charge transporting substance, and an insulating binder on a conductive support 11.
Again, the disazo pigment 13 is a charge generating substance. For other photoreceptors, the charge generation layer and charge transport layer shown in FIG. 2 may be reversed. The thickness of the photosensitive layer is as shown in FIG.
The thickness of 5 is preferably 0.01 to 5μ, more preferably
It is 0.05~2μ. If the thickness is less than 0.01μ, the generation of charge is not sufficient, and if it is more than 5μ, the residual potential is too high to be practical. Charge transport layer 1
The thickness of 7 is preferably 3 to 50μ, more preferably 5 to 20μ. If the thickness is less than 3μ, the amount of charge will be insufficient, and if it is more than 50μ, the residual potential will be too high to be practical. The charge generation layer 15 is mainly composed of a disazo pigment represented by the above general formula, and may further contain a binder, a plasticizer, and the like.
Further, the proportion of the disazo pigment in the charge generation layer is preferably 30% by weight or more, more preferably 50% by weight.
That's all. The charge transport layer 17 is mainly composed of a charge transport substance and a binder, and may further contain a plasticizer. The proportion of charge transport material in the charge transport layer is from 10 to 95% by weight, preferably from 30 to 90% by weight. If the proportion of the charge transport substance is less than 10% by weight, almost no charge transport occurs;
If it exceeds 95% by weight, the mechanical strength of the photoreceptor film will be so poor that it cannot be put to practical use. In the case of the photoreceptor shown in FIG. 3, the photosensitive layer 19'
The thickness is preferably 3 to 50μ, more preferably 5 to 20μ. Further, the proportion of the disazo pigment in the photosensitive layer 19' is preferably 50% by weight or less, more preferably 20% by weight or less, and the proportion of the charge transport substance is preferably 10 to 95% by weight, more preferably 30% by weight or less. ~90% by weight. The gist of the present invention is to use a specific disazo pigment represented by the above general formula as a charge generating substance in an electrophotographic photoreceptor, and to use other components such as a conductive support and a charge transporting substance. Any of the conventionally known ones can be used, and these will be specifically explained below. The conductive support used in the photoreceptor of the present invention may be a metal plate made of aluminum, copper, zinc, etc., a plastic sheet made of polyester, or a plastic film on which a conductive material such as aluminum or SnO ₂ is deposited, or a conductive support. Treated paper, etc. is used. As a binder, polyamide, polyurethane,
Examples include condensation resins such as polyester, epoxy resin, polyketone, and polycarbonate, and vinyl polymers such as polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, and polyacrylamide, but all resins that are insulating and adhesive can be used. Can be used. Examples of the plasticizer include halogenated paraffin, polychlorinated biphenyl, dimethylnaphthalene, and dibutyl phthalate. In addition, silicone oil or the like may be added to improve the surface properties of the photoreceptor. Charge transport materials include hole transport materials and electron transport materials. Examples of the hole transport substance include compounds represented by the following general formulas (1) to (11). [In the formula, R ₁ represents a methyl group, ethyl group, 2-hydroxyethyl group, or 2-chloroethyl group, R ₂ represents a methyl group, ethyl group, benzyl group, or phenyl group, and R ₃ represents hydrogen, chlorine, bromine,
It represents an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a dialkylamino group, or a nitro group. ] [In the formula, Ar is a naphthalene ring, anthracene ring,
It represents a styryl group or a substituted product thereof, or a pyridine ring, a furan ring, or a thiophene ring, and R represents an alkyl group or a benzyl group. ] [In the formula, R ₁ represents an alkyl group, a benzyl group, a phenyl group, and R ₂ represents hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a dialkylamino group, a dialkylamino group, or It represents a diarylamino group, n represents an integer of 1 to 4, and when n is 2 or more, R ₂ may be the same or different. R ₃ represents hydrogen or a methoxy group. ] [In the formula, R ₁ represents an alkyl group having 1 to 11 carbon atoms, a substituted or unsubstituted phenyl group, or a heterocyclic group, and R ₂ and R ₃ may be the same or different, and hydrogen, -4 represents an alkyl group, a hydroxyalkyl group, a chloroalkyl group, or a substituted or unsubstituted aralkyl group, and R ₂ and R ₃ may be bonded to each other to form a nitrogen-containing heterocycle. R ₄ may be the same or different and hydrogen,
Represents an alkyl group having 1 to 4 carbon atoms, an alkoxy group, or a halogen. ] [In the formula, R represents hydrogen or a halogen atom, and Ar represents a substituted or unsubstituted phenyl group, naphthyl group, anthryl group, or carbazolyl group. ] [In the formula, R ₁ represents hydrogen, halogen, cyano group, alkoxy group having 1 to 4 carbon atoms, or alkyl group having 1 to 4 carbon atoms, and Ar is

[expression] or

[Formula], R ₂ represents an alkyl group having 1 to 4 carbon atoms, and R ₃ represents hydrogen, halogen,
represents an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a dialkylamino group, and n
is 1 or 2, and when n is 2, R ₃ may be the same or different, and R ₄ and R ₅ are hydrogen, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted alkyl group. represents a benzyl group. ] [In the formula, R is a carbazolyl group, pyridyl group, thienyl group, indolyl group, furyl group, or a substituted or unsubstituted phenyl group, styryl group, naphthyl group, or anthryl group, and these substituents are dialkylamino groups , an alkyl group, an alkoxy group, a carboxy group or an ester thereof, a halogen atom, a cyano group, an aralkylamino group, an N-alkyl-N aralkylamino group, an amino group, a nitro group, and an acetylamino group. represent. ] [In the formula, R ₁ represents a lower alkyl group or a benzyl group, and R ₂ represents a hydrogen atom, a lower alkyl group,
Represents 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, and n is 1 or 2.
represents an integer. ] [In the formula, R ₁ represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom, and R ₂ and
R ₃ represents an alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group, R ₄ represents a hydrogen atom or a substituted or unsubstituted phenyl group, and Ar represents a phenyl group or a naphthyl group. represent. ] [In the formula, n is an integer of 0 or 1, R ₁ is a hydrogen atom, an alkyl group, or a substituted or unsubstituted phenyl group, and A is

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[Formula] represents a 9-anthryl group or a substituted or unsubstituted N-alkylcarbazolyl group, where R ₂ is a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or

[Formula] (However, R ₃ and R ₄ represent an alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group, and R ₃ and R ₄ may form a ring)
and m is an integer of 0, 1, 2 or 3, and when m is 2 or more, R ₂ may be the same or different. ] In the formula, R ₁ , R ₂ and R ₃ represent hydrogen, a lower alkyl group, a lower alkoxy group, a dialkylamino group or a halogen atom, and n represents 0 or 1. ] The compound represented by general formula (1) includes, for example, 9
-Ethylcarbazole-3-aldehyde 1-methyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde 1-benzyl-1-phenylhydrazone, 9-ethylcarbazole-3-
Examples include aldehyde 1,1-diphenylhydrazone. Examples of the compound represented by the general formula (2) include 4-diethylaminostyrene-β-aldehyde 1-ethyl-1-phenylhydrazone, 4-methoxynaphthalene-1-aldehyde 1-benzyl-
Examples include 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-
Examples include benzyl-1-phenylhydrazone and 4-dibenzylaminobenzaldehyde-1,1-diphenylhydrazone. Examples of the compound represented by the general formula (4) include 1,1-bis(4-dibenzylaminophenyl)propane, tris(4-diethylaminophenyl)methane, and 1,1-bis(4-dibenzylaminophenyl)propane. phenyl)propane, 2,
2-dimethyl-4,4'-bis(dimethylamino)
-Triphenylmethane, etc. Examples of the compound represented by the general formula (5) include 9-(4-diethylaminostyryl)anthracene, 9-bromo-
Examples include 10-(4-diethylaminostyryl)anthracene. Examples of the compound represented by the general formula (6) include 9-(4-dimethylaminobenzylidene)fluorene, 3-(9-fluorenylidene)
-9-ethylcarbazole and the like. General formula (7)
Examples of the compound represented by include 1,2-bis(4-diethylaminostyryl)benzene,
There is 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-diphenylaminostilbene, and 4-diphenylaminostilbene.
Examples include ditolylaminostilbene, 1-(4-diphenylaminostyryl)naphthalene, and 1-(4-diethylaminostyryl)naphthalene. Examples of the compound represented by the general formula (10) include 4'-diphenylamino-α-phenylstilbene, 4'-
Examples include methylphenylamino-α-phenylstilbene. The compound represented by general formula (11) includes:
For example, 1-phenyl-3-(4-diethylaminophenyl)-5-(4-diethylaminophenyl)pyrazoline, 1-phenyl-3-(4-dimethylaminostyryl)-5-(4-diethylaminophenyl)pyrazoline, etc. There is. Other hole transport substances include, for example, 2,
5-bis(4-diethylaminophenyl)-1,
3,4-oxadiazole, 2,5-bis[4-
(4-diethylaminostyryl)phenyl]-1,
Oxadiazole compounds such as 3,4-oxadiazole, 2-(9-ethylcarbazolyl-3-)-5(4-diethylaminophenyl)-1,3,4-oxadiazole, 2-vinyl -4-(2-
Examples include low molecular weight compounds such as oxazole compounds such as chlorophenyl)-5-(4-diethylaminophenyl)oxazole and 2-(4-diethylaminophenyl)-4-phenyloxazole. Further, polymeric compounds such as poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, pyrene formaldehyde resin, and ethylcarbazole formaldehyde resin can also be used. Examples of electron transport substances include chloranil, bromoanil, 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]thiophen-4-one, 1,3,7-trinitrodibenzothiophene, 5,5-dioxide and the like. These charge transport substances may be used alone or in combination of two or more. In any 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. Suitable materials for these layers include polyamide, nitrocellulose, and aluminum oxide.
Further, the film thickness is preferably 1 μm or less. To make the photoreceptor shown in Figure 2, disazo pigments USP 3973959, USP 3996049 are deposited on a conductive support.
Alternatively, fine particles of a disazo pigment are dispersed in a suitable solvent in which a binder is dissolved if necessary, and this is coated on a conductive support and dried. If necessary, the surface is finished by buffing as shown in JP-A-51-90827, or after adjusting the film thickness, a solution containing a charge transporting substance and a binder is applied and dried. It can be obtained by In order to produce the photoreceptor shown in FIG. 3, fine particles of a disazo pigment are dispersed in a solution containing a charge transporting substance and a binder, and the dispersion is applied onto a conductive support and dried. In either case, the disazo pigment used in the present invention is used after being ground to a particle size of 5 μm or less, preferably 2 μm or less, using a ball mill or the like.
Application may be carried out by conventional means, such as a doctor blade, dipping, wire bar, etc. To perform copying using the photoreceptor of the present invention, the surface of the photosensitive layer is charged and exposed, and then developed.
If necessary, this can be achieved by transferring to paper or the like. As is clear from the above description and the Examples and Comparative Examples described later, the electrophotographic photoreceptor of the present invention uses a disazo pigment having a xanthone skeleton as a charge-generating substance, and is therefore superior to conventional photoreceptors. It is easy to manufacture, has high sensitivity,
Moreover, it has excellent properties such as a photosensitive wavelength range in the short wavelength range (450 to 600 nm) and stable characteristics even under repeated actions of the photoreceptor. EXAMPLES Next, the present invention will be specifically explained using 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 tetrahydrofuran solution (solid content concentration 2%) of polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.), and 3700 parts by weight of tetrahydrofuran were pulverized and mixed in a ball mill. The resulting dispersion was applied using a doctor blade onto the aluminum surface of an aluminum-deposited polyester base (conductive support) and air-dried to form a charge generation layer with a thickness of approximately 1 μm. On this charge generation layer, 9-
2 parts by weight of ethylcarbazole-3-aldehyde 1-methyl-1-phenylhydrazone, 2 parts of polycarbonate resin (Panlite K-1300: manufactured by Teijin Ltd.)
A solution prepared by mixing and dissolving 16 parts by weight of tetrahydrofuran and 16 parts by weight of tetrahydrofuran 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 with a thickness of about 20 μm. A laminated type photoreceptor No. 1 shown in FIG. 2 was prepared. Examples 2 to 26 Photoreceptors Nos. 2 to 26 were prepared in the same manner as in Example 1, except that disazo pigments shown in Table 1 below were used in place of disazo pigment No. 1 used in Example 1. Examples 27-47 1-phenyl-3-(4-
Photoreceptors Nos. 27 to 47 were prepared in the same manner as in Example 1, except that pyrazoline (diethylaminostyryl)-5-(4-diethylaminophenyl) and the disazo pigment shown in Table 2 below were used. Examples 48 to 66 Photoreceptors Nos. 48 to 66 were prepared in the same manner as in Example 1, except that 9-(4-diethylaminostyryl)anthracene was used as the charge transport substance and the disazo pigment shown in Table 3 below was used. did. Examples 67 to 74 Using 1,1-bis(4-dibenzylaminophenyl)propane as the charge transport substance, the following table-
Example 1 except that the disazo pigment shown in 4 was used.
Photoreceptors Nos. 67 to 74 were prepared in the same manner as described above. These photoreceptors No. 1 to 74 were negatively charged by performing -6KV corona discharge for 20 seconds using an electrostatic copying paper testing device (manufactured by Kawaguchi Electric Seisakusho Co., Ltd., model SP428). , leave it in a dark place for 20 seconds, measure the surface potential Vpo (V) at that time, then irradiate the surface with light using a tungsten lamp at an illuminance of 4.5 lux until the surface potential is 1/1 of Vpo. Find the time (seconds) until it becomes 2, and calculate the exposure amount E1/2
(lux/second) was calculated. Table 1 shows the results.
- Shown in Table-4.

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[Table] Comparative Example 1 A laminated photoreceptor was prepared as described below, using a perylene derivative as the charge generation layer and an oxadiazole derivative as the charge transport layer, as described in US Pat. No. 3,871,882. N,N'-dimethylperylene-3,4,9,10-tetracarboxylic acid diimide as a charge-generating substance was deposited on an aluminum plate under conditions of a vacuum degree of 10 ^-5 mmHg, a deposition source temperature of 350°C, and a deposition time of 3 minutes. A charge generation layer was formed by vacuum evaporation. Next, 5 parts by weight of 2,5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole,
A solution consisting of 5 parts by weight of polyester resin (manufactured by DuPont, Polyester Adhesive 49000) and 90 parts by weight of tetrahydrofuran was applied and heated at 120°C.
The sample was dried for 10 minutes to form a charge transport layer with a thickness of about 10 μm, and Comparative Photoreceptor No. 1 was prepared. Comparative Example 2 A laminated photoreceptor described in Japanese Patent Publication No. 55-42380, using chlordiane blue as the charge generation layer and a hydrazone compound as the charge transport layer, was prepared as follows. A solution consisting of 25 parts by weight of Chlordiane blue, 1240 parts by weight of ethylenediamine, 990 parts by weight of n-butylamine and 2740 parts by weight of tetrahydrofuran was applied onto the aluminum surface of the aluminum-deposited polyester base with a wet gap of 25 μm using a doctor blade and dried. , a charge generation layer was formed. Next, a solution consisting of 10 parts by weight of 4-diethylaminobenzaldehyde 1,1-diphenylhydrazone, 10 parts by weight of polycarbonate resin (the same resin used in Example 1), and 80 parts by weight of tetrahydrofuran was then applied onto the charge generating layer. , applied using a doctor blade and dried to a thickness of approximately 18 μm.
Comparative laminated photoreceptor No. 2
It was created. Comparative Example 3 A laminated photoreceptor described in JP-A-55-84943 using a distyrylbenzene-based disazo compound as the charge generation layer and a hydrazone compound as the charge transport layer was prepared as follows. did. 4′,4″-bis[2-hydroxy-3-(2,4
-dimethylphenylcarbamoyl)-1-naphthylazo]-1,4-distyrylbenzene 20 parts by weight,
Polyvinyl butyral (Denka Butyral #4000
-1, manufactured by Tokyo Denki Kagaku Co., Ltd.), 7 parts by weight of polymethyl methacrylate (Dyanal BR-80, manufactured by Mitsubishi Rayon Co., Ltd.), and 300 parts by weight of tetrahydrofuran were milled in a ball mill for 3 hours. After diluting this dispersion with 2,700 parts by weight of tetrahydrofuran, it was applied onto the aluminum surface of an aluminum-deposited polyester base (conductive support) using a doctor blade and dried to form a charge generation layer with a thickness of approximately 0.3 μm. Formed. Then, 9-ethylcarbazole-3-aldehyde-
10 parts by weight of 1-methyl-1-phenylhydrazone,
10 parts by weight of polycarbonate resin (same resin used in Example 1) and 80 parts by weight of tetrahydrofuran
A solution consisting of parts by weight was applied using a doctor blade and dried to form a charge transport layer having a thickness of about 13 μm, thereby producing a laminated comparative photoreceptor No. 3. The spectral sensitivities of these comparative photoreceptors No. 1 to 3 and photoreceptors No. 4 and No. 7 of the present invention were measured in accordance with the following measurement procedure in order to investigate their sensitive wavelength ranges. First, the photoreceptor is charged to a surface potential of -800 volts or more by corona discharge in a dark place, dark decayed until the surface potential reaches -800 volts, and when the surface potential reaches -800 volts, the monochromator The intensity on the photoreceptor surface is 1 μw/cm ²
The photoreceptor was irradiated with monochromatic light. Then, the time (seconds) until the surface potential attenuated to -400V was determined, and the half-reduced exposure amount (μW·sec/cm ² ) was calculated. On the other hand, the apparent potential difference obtained by exposure is 400
Find the potential difference actually obtained by exposure by subtracting the potential attenuation due to dark decay from volts, and calculate the light attenuation rate (Volt・cm ²・μW ^-1・sec ^-1 ) was calculated and used as the sensitivity. The spectral sensitivities obtained in this way are
Shown in the figure. Figure 4: Photoreceptor No. 4 of the present invention Figure 5: Photoreceptor No. 7 of the invention Figure 6: Comparative photoreceptor Nos. 1, 2, 3 Tables 1 to 4 and Figure 4 From the results shown in FIG. 6, it can be seen that the photoreceptor of the present invention has high sensitivity, and its sensitive wavelength range is about 460 to 600 nm. Further, photoreceptors No. 4 and No. 7 of the present invention were installed in a copying machine model Ricopy P-500 manufactured by Ricoh Co., Ltd., and image production was repeated 10,000 times. As a result, clear images were obtained without any of the photoreceptors changing due to repeated copying processes. From this, it can be understood that the photoreceptor of the present invention is also excellent in durability.

[Brief explanation of drawings]

FIG. 1 shows an infrared absorption spectrum (KBr tablet method) of disazo pigment No. 1 used in the present invention. FIGS. 2 and 3 are enlarged sectional views showing examples of the structure of the photoreceptor of the present invention. 11... Conductive support, 13... Disazo pigment, 1
5... Charge generation layer, 17... Charge transport layer, 19,1
9'...Photosensitive layer. FIGS. 4 to 6 are graphs showing the spectral sensitivity characteristics of the photoreceptor of the present invention and a comparative photoreceptor.

Claims (1)

[Claims] 1 General formula () on a conductive support (In the formula, A represents a coupler residue.) An electrophotographic photoreceptor comprising a disazo pigment represented by the following formula as an active ingredient.