JPH0434743B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an electrophotographic photoreceptor characterized by having an electrophotographic photosensitive layer containing a novel disazo compound. The photoconductive process of an electrophotographic photoreceptor consists of (1) the process of generating electric charge by exposure to light, and (2) the process of transporting the electric charge. A selenium photosensitive plate is an example of performing (1) and (2) using the same material. On the other hand, a combination of amorphous selenium and poly-N-vinylcarbazole is well known as an example of performing (1) and (2) using separate substances. The method of performing (1) and (2) using separate substances expands the selection range of materials used for the electrophotographic photoreceptor, and accordingly improves the electrophotographic properties such as sensitivity and acceptance potential of the electrophotographic photoreceptor. It has the advantage that materials convenient for the production of electrophotographic photoreceptor coatings can be selected from a wide range. Conventionally, inorganic materials such as selenium, cadmium sulfide, and zinc oxide have been used as photoconductive materials for electrophotographic photoreceptors used in electrophotography. Electrophotography has already been covered by Carlson's U.S. Patent No.
No. 2,297,691 discloses a photoconductive material consisting of a support coated with a dark insulating material whose electrical resistance changes depending on the dose of radiation received during image exposure. This photoconductive material is generally prepared in the dark after dark adaptation for a suitable period of time.
First, a uniform surface charge is given. The material is then imagewise exposed to a pattern of radiation that has the effect of reducing the surface charge depending on the relative energy contained in different parts of the radiation pattern. The surface charge or electrostatic latent image thus left on the surface of the photoconductive material layer (electrophotographic photosensitive layer) then becomes a visible image when the screen is contacted with a suitable electrometric indicator material, i.e., toner. . The toner is contained in an insulating liquid or in a dry carrier, and in either case, it can be deposited on the surface of the electrophotographic photosensitive layer depending on the charge pattern. The deposited display material can be fixed by known means such as heat, pressure, and solvent vapor. The electrostatic latent image can also be transferred to a second support (e.g. paper, film, etc.).
can be transferred to Similarly, the electrostatic latent image is
It is also possible to transfer the image to a support and develop it there. Electrophotography is one of the image forming methods in which images are formed in this manner. The basic characteristics required of an electrophotographic photoreceptor in such electrophotography are (1) ability to be charged to an appropriate potential in the dark, (2) less dissipation of charge in the dark, ( 3) The charge can be quickly dissipated by light irradiation. It is true that the conventionally used inorganic materials have many advantages, but also have various disadvantages. For example, selenium, which is currently widely used, fully satisfies the conditions (1) to (3) above, but the manufacturing conditions are difficult, the manufacturing cost is high, it is not flexible, and it cannot be processed into a belt shape. It also has disadvantages, such as being difficult to handle and being sensitive to heat and mechanical shock, requiring careful handling. Cadmium sulfide and zinc oxide are used as electrophotographic photoreceptors by being dispersed in a resin as a binder, but they have mechanical drawbacks such as smoothness, hardness, tensile strength, and abrasion resistance, so they cannot be used as they are. cannot be used repeatedly. In recent years, electrophotographic photoreceptors using various organic materials have been proposed in order to eliminate the drawbacks of these inorganic materials, and some of them have been put into practical use. For example, poly-N-vinylcarbazole and 2,4,7
-Electrophotographic photoreceptor consisting of trinitrofluoren-9-one (US Patent No. 3,484,237), poly-N-vinylcarbazole sensitized with pyrylium salt dye (Japanese Patent Publication No. 1983-25658), mainly composed of organic pigments. These include an electrophotographic photoreceptor (Japanese Unexamined Patent Publication No. 47-37543), and an electrophotographic photoreceptor whose main component is a eutectic complex consisting of a dye and a resin (Japanese Unexamined Patent Publication No. 47-10735). Although these organic electrophotographic photoreceptors have improved the mechanical properties and flexibility of the inorganic electrophotographic photoreceptors to some extent, they generally have low photosensitivity and are not suitable for repeated use, so they do not meet the requirements of electrophotographic photoreceptors. I was not satisfied with that. As a result of intensive research to improve the drawbacks of the conventional electrophotographic photoreceptors, the present inventors have found that an electrophotographic photoreceptor containing a novel disazo compound has high sensitivity and high durability for practical use. The present invention was developed based on the discovery that the present invention has the following properties. The present invention relates to an electrophotographic photoreceptor characterized by having an electrophotographic photosensitive layer containing a novel disazo compound (disazo pigment) represented by the following general formula [1]. The present invention is (1) an electrophotographic photoreceptor having an electrophotographic photosensitive layer containing a disazo compound represented by the following general formula [1]. In the above general formula [1], A is

【formula】

【formula】

【formula】

[Formula] Also teeth

[Formula];
Represents an atomic group necessary to form multiple rings such as a carbazole ring, benzocarbazole ring, and dibenzofuran ring (all rings may be substituted or unsubstituted), and Y is

[Formula] or -COOR ⁵ , R ¹ represents an alkyl group having 1 to 8 carbon atoms, a phenyl group, or a substituted product thereof, R ² represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms,
Carbamoyl group, carboxyl group, carbon number 1-10
represents an alkoxycarbonyl group, an aryloxycarbonyl group having 6 to 12 carbon atoms, or a substituted or unsubstituted amino group, and R ³ and R ⁵ represent an aromatic group such as an alkyl group having 1 to 8 carbon atoms, a phenyl group, or a naphthyl group. represents a plural aromatic ring group such as a group group, a dibenzofuranyl group, a carbazolyl group, or a substituent thereof, R ⁴ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms,
Represents a phenyl group or a substituted product thereof. The disazo compound represented by the general formula [1] will be explained in more detail. X is a group that can be fused with a benzene ring to which a hydroxyl group and Y are bonded to form an aromatic ring such as a naphthalene ring or anthracene ring, or a heterocyclic ring such as an indole ring, a carbazole ring, a benzocarbazole ring, or a dibenzofuran ring. It is. When X is an aromatic ring or a heterocyclic ring having a substituent, the substituent is a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, etc.), a lower alkyl group, preferably a lower alkyl group having 1 to 8 carbon atoms ( For example, methyl group, ethyl group, propyl group, butyl group, isopropyl group, isobutyl group, etc.), and the number of substituents is 1 or 2, and if there are 2 substituents, they are the same. But they can be different. R' represents an alkyl group having 1 to 8 carbon atoms, a phenyl group, or a substituted product thereof. When R ¹ is an unsubstituted alkyl group, specific examples include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, isopropyl group,
Isobutyl group, isoamyl group, isohexyl group,
Examples include neopentyl group and tert-butyl group. When R ¹ is a substituted alkyl group, the substituent includes a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, a cyano group, an amino group, an alkylamino group having 1 to 12 carbon atoms, and an alkyl group having 1 to 12 carbon atoms. Dialkylamino group having 2, halogen atom, carbon number 6-15
There are aryls such as Examples include hydroxyalkyl groups (e.g., hydroxymethyl, 2
-hydroxyethyl group, 3-hydroxypropyl group, 2-hydroxypropyl group, etc.), alkoxyalkyl group (e.g., methoxymethyl group, 2-methoxyethyl group, 3-methoxypropyl group, ethoxymethyl group, 2-ethoxyethyl group) ), cyanoalkyl groups (e.g., cyanomethyl group, 2-cyanoethyl group, etc.), aminoalkyl groups (e.g.,
(aminomethyl group, 2-aminoethyl group, 3-aminopropyl group, etc.), (alkylamino)alkyl group (for example, (methylamino)methyl group, 2-(methylamino)ethyl group, (ethylamino)methyl group) , (dialkylamino)alkyl group (e.g.
(dimethylamino)methyl group, 2-(dimethylamino)ethyl group, etc.), halogenoalkyl group (e.g.
fluoromethyl group, chloromethyl group, bromomethyl group, etc.), aralkyl group (e.g. benzyl group,
phenethyl group, etc.). When R ¹ is a substituted phenyl group, the substituent includes a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, a cyano group, an amino group, an alkylamino group having 1 to 12 carbon atoms, and an alkyl group having 1 to 12 carbon atoms. Dialkylamino group having 2, halogen atom, carbon number 1-6
There are alkyl groups, nitro groups, etc. Examples include hydroxyphenyl group, alkoxyphenyl group (e.g., methoxyphenyl group, ethoxyphenyl group, etc.), cyanophenyl group, aminophenyl group, (alkylamino)phenyl group (e.g., (methylamino)phenyl group, (ethylamino)phenyl group, etc.), (dialkylamino)phenyl group (e.g., (dimethylamino)phenyl group, etc.), halogenophenyl group (e.g., fluorophenyl group, chlorophenyl group, bromophenyl group, etc.), alkylphenyl group ( For example, tolyl group, ethyl phenyl group, cumenyl group, xylyl group, mesityl group, etc.),
Lists a nitrophenyl group and a substituent having two or three of these substituents (which may be the same or different) (the position of the substituents or the positional relationship between the substituents is arbitrary) be able to. R ² is a hydrogen atom, a lower alkyl group having 1 to 6 carbon atoms, a carbamoyl group, a carboxyl group, an alkoxycarbonyl group having an alkoxy group having 1 to 10 carbon atoms, or an aryloxy group having an aryloxy group having 6 to 12 carbon atoms. There are carbonyl groups and substituted or unsubstituted amino groups. When R ² is a substituted amino group, specific examples thereof include methylamino group, ethylamino group, propylamino group, phenylamino group, tolylamino group, benzylamino group, phenethylamino group, dimethylamino group, diethylamino group, diphenylamino group, etc. be able to. When R ² is a lower alkyl group, specific examples include methyl group, ethyl group, propyl group, butyl group,
Examples include isopropyl group and isobutyl group. When R ² is an alkoxycarbonyl group, specific examples include a methoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonyl group, a butoxycarbonyl group, an isopropoxycarbonyl group, a benzyloxycarbonyl group, and the like. When R ² is an aryloxycarbonyl group, specific examples thereof include a phenoxycarbonyl group and a toroxycarbonyl group. R ³ and R ⁵ include alkyl groups having 1 to 8 carbon atoms, aromatic groups such as phenyl groups and naphthyl groups, and heteroaromatic groups such as oxygen atoms, nitrogen atoms, and sulfur atoms such as dibenzofuranyl groups and carbazolyl groups. There are ring groups or their substituents. When R ³ or R ⁵ is a substituted or unsubstituted alkyl group, examples thereof include the same groups as the above-mentioned examples of the substituted or unsubstituted alkyl group for R ¹ . When R ³ or R ⁵ is a substituted aromatic group such as a substituted phenyl group, a substituted naphthyl group, a substituted heteroaromatic ring group such as a substituted dibenzofuranyl group or a substituted carbazolyl group, examples of the substituent include a hydroxyl group and a cyano group. , nitro group, halogen atom (e.g., fluorine atom, chlorine atom, bromine atom, etc.), alkyl group having 1 to 12 carbon atoms (e.g., methyl group, ethyl group, propyl group, isopropyl group, etc.), having 1 to 12 carbon atoms Alkoxy group (e.g. methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, isopropoxy group, isobutoxy group, isoamyloxy group, tert-butoxy group, neopentyloxy group, etc.), amino group, carbon number 1 ~12 alkylamino groups (e.g. methylamino, ethylamino,
propylamino group, etc.), dialkylamino group having two alkyl groups having 1 to 12 carbon atoms (e.g., dimethylamino group, diethylamino group, N-methyl-N-ethylamino group, etc.), aryl having 6 to 12 carbon atoms An amino group (e.g., phenylamino group, tolylamino group, etc.), an aryl group having 6 to 15 carbon atoms,
diarylamino groups (e.g. diphenylamino groups, etc.), carboxyl groups, alkali metal carboxylate groups (examples of alkali metals (cations), such as Na, K, Li, etc.), alkali metal sulfonato groups (alkali metals (cations) For example, Na,
K, Li, etc.), alkylcarbonyl groups (e.g.
acetyl group, propionyl group, benzylcarbonyl group, etc.), arylcarbonyl group having an aryl group having 6 to 12 carbon atoms (for example, benzoyl group, toyl group, furoyl group, etc.), alkylthio group having 1 to 12 carbon atoms (for example, methylthio group, ethylthio group, etc.) or an arylthio group having 1 to 12 carbon atoms (e.g., phenylthio group, tolylthio group, etc.), and the number of substituents is 1 to 3, and the number of substituents is 1 to 3. When bonded, they may be the same or different from each other and may be in any combination, and the bonding positions of the substituents may be arbitrary. Examples of R ⁴ include a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a phenyl group, or a substituted product thereof. When R ⁴ is a substituted or unsubstituted alkyl group or phenyl group, the same groups as the above-mentioned examples of the substituted or unsubstituted alkyl group and phenyl group for R ³ and R ⁵ can be mentioned. A derived from a coupler provides a photoconductive composition or an electrophotographic photosensitive layer with high photosensitivity, and it is said that disazo compounds can be produced at low cost because the raw materials for production can be easily obtained. from a point of view

[Formula] is preferred. Specific examples of the compounds of the present invention are given below. The novel disazo compound of the present invention can be produced by a known method. That is, 2,
After diazotization of 6-bis(4-aminostyryl)naphthalene and isolation as a tetrazonium salt,
This can be easily produced by coupling reaction with a compound corresponding to each of the above-mentioned pigments (for example, a coupler such as naphthol AS type) in a suitable organic solvent such as N,N-dimethylformamide in the presence of an alkali. . The disazo compound of the present invention can be used as a disazo pigment. For example, the disazo compound [1] can be produced according to Synthesis Example 1. Synthesis Example 1 2.20 g of 2,6-bis(4-aminostyryl)naphthalene was added to dilute hydrochloric acid prepared from 5 ml of concentrated hydrochloric acid and 5 ml of water, and the mixture was thoroughly stirred on a 60° C. water bath for about 30 minutes. Next, this mixture was cooled to 0°C, and a solution of 881 mg of sodium nitrite dissolved in 3 ml of water was added dropwise thereto at 0°C over about 30 minutes. Thereafter, the mixture was stirred at the same temperature for 1 hour, the resulting tetrazonium chloride substance was separated, the tetrazonium salt was dissolved in water, and the solution and liquid were combined. 6 ml of 42% borofluoric acid was added to the combined solution to collect precipitated crystals. After washing the crystals with a small amount of cold water, drying them gives 2.97 g of orange-red crystals of tetrazonium fluoroborate.
(yield 87%). Next, 280 mg of the tetrazonium salt obtained in this way
and 263 mg of 2-hydroxy-3-naphthoic acid anilide as a coupler were dissolved in 12 ml of N,N-dimethylformamide, and 500 mg of sodium acetate was added to the solution.
A solution consisting of 2.0 mg and 2 ml of water was added dropwise at a temperature of 0° C. over about 20 minutes, and then stirred at room temperature for about 2 hours. After that, remove the formed precipitate and wash it with 200ml of water.
This was washed with 100 ml of N,N-dimethylformamide while stirring. Next, it was washed with ethanol and dried, and 410 mg of disazo pigment of compound (1) (yield 90
%) was obtained. Elemental analysis at decomposition temperature of 300°C or above C ₆₀ H ₄₂ O ₄ N ₆ Calculated value C, 79.1% H, 4.65% N, 9.22% Actual value C, 79.3% H, 4.71% N, 9.43% IR absorption spectrum (KBr tablet ) Amide 1680 cm ^-1 Visible absorption spectrum Maximum absorption wavelength 543 nm (in dichloromethane solution) Synthesis Examples 2 to 11 Disazo compounds (2), (3), ( Four),
(5), (11), (13), (15), (25), (26), (46
) were synthesized respectively. Table 1 shows the decomposition temperature, elemental analysis value, IR absorption spectrum, and visible absorption spectrum of each disazo compound.

【table】

【table】

[Table] The infrared absorption spectrum (KBr method) of disazo compound (15) is shown in Figure 1. Other disazo compounds also change the coupler.
It can be synthesized according to the above synthesis example. The electrophotographic photoreceptor of the present invention has an electrophotographic photosensitive layer containing one or more disazo compounds represented by the above general formula. Various forms of electrophotographic photoreceptors are known, and the electrophotographic photoreceptor of the present invention may be any type of photoreceptor, but it usually has an electrophotographic photoreceptor structure of the type exemplified below. . (1) An electrophotographic photosensitive layer comprising a disazo compound dispersed in a binder or a charge carrier transport medium is provided on a conductive support. (2) A charge carrier generation layer containing a disazo compound as a main component is provided on a conductive support, and a charge carrier transporting medium layer is provided on top of the charge carrier generation layer. The disazo compound of the present invention acts as a photoconductive substance, and when it absorbs light, it generates charge carriers with extremely high efficiency.The generated charge carriers can also be transported using the disazo compound as a medium, but the charge carrier transport compound is It is more effective to transport it as a medium. To create an electrophotographic photoreceptor of type (1), fine particles of a disazo compound are dispersed in a binder solution or a solution containing a charge carrier transport compound and a binder, and this is coated on a conductive support and dried. . The thickness of the electrophotographic photosensitive layer at this time was 3
-30μ, preferably 5-20μ. To create an electrophotographic photoreceptor of type (2), a disazo compound is vacuum-deposited on a conductive support, or
The disazo compound may be dissolved in a solvent such as an amine and applied, or fine particles of the disazo compound may be dispersed in a suitable solvent or, if necessary, a solvent in which a binder has been dissolved, and after drying, the charge carrier transport compound and the disazo compound are applied. Obtained by applying and drying a solution containing a binder. At this time, the thickness of the disazo compound layer serving as the charge carrier generation layer is preferably 4μ or less, preferably 2μ or less, and the thickness of the charge carrier transport medium layer is 3 to 3μ.
The thickness is preferably 30μ, preferably 5 to 20μ. The disazo compound used in the photoreceptors of types (1) and (2) is used after being ground to a particle size of 5 μm or less, preferably 2 μm or less using a dispersing machine such as a ball mill, sand mill, or vibration mill. If the amount of disazo compound used in the type (1) electrophotographic photoreceptor is too small, the sensitivity will be poor;
If the amount is too high, the charging property may deteriorate and the strength of the electrophotographic photosensitive layer may become weak.
It is preferably 0.01 to 2 times by weight, preferably 0.05 to 1 times by weight, and the proportion of the charge carrier transport compound added as needed is preferably in the range of 0.1 to 2 times by weight, preferably 0.3 to 1.3 times by weight, based on the weight of the binder. In the case of a charge carrier transporting compound which itself can be used as a binder, the amount of the disazo compound added is preferably 0.01 to 0.5 times the weight of the binder. In addition, when coating and forming a disazo compound-containing layer that becomes a charge carrier generation layer in the electrophotographic photoreceptor of type (2), the amount of disazo compound used is preferably at least 1 times the weight of the binder resin, and if it is less than that, sufficient photosensitivity is achieved. is not obtained. The proportion of the charge carrier transport compound in the charge carrier transport medium is preferably 0.2 to 2 times, preferably 0.3 to 1.3 times by weight, the binder. If a polymeric charge carrier transport compound is used which itself can be used as a binder, no other binder can be used. When producing the electrophotographic photoreceptor of the present invention, additives such as a plasticizer or a sensitizer may be used together with the binder. The conductive support used in the electrophotographic photoreceptor of the present invention includes a metal plate made of aluminum, copper, zinc, etc., a plastic sheet made of polyester, etc., or a plastic film such as aluminum,
A material coated with a conductive material such as SnO ₂ by vapor deposition or dispersion, or paper treated with conductive treatment is used. As a binder, polyamide, polyurethane, polyester, epoxy resin, polyketone,
Examples include condensation resins such as polycarbonate, heavy vinyl materials such as polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, and polyacrylamide, but any resin that is insulating and adhesive can be used. Plasticizers include biphenyl, biphenyl chloride,
o-terphenyl, p-terphenyl, dibutyl phthalate, dimethyl glycol phthalate, dioctyl phthalate, triphenyl phosphoric acid, methylnaphthalene, benzophenone, chlorinated paraffin, polypropylene, polystyrene, dilaurylthiodipropionate, 3,5-dinitrosalicylic acid, various fluorocarbons Examples include hydrocarbons. In addition, silicone oil or the like may be added to improve the surface properties of the electrophotographic photoreceptor. Examples of the sensitizer include chloranil, tetracyanoethylene, methyl violet, rhodamine B, cyanine dye, merocyanine dye, pyrylium dye, thiapyrylium dye and the like. Compounds that transport charge carriers are generally classified into two types: compounds that transport electrons and compounds that transport holes, and both can be used in the electrophotographic photoreceptor of the present invention. Compounds that transport electrons include compounds having an electron-withdrawing group, such as 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 9-dicyanomethylene-2,4 , 7-trinitrofluorenone, 9-dicyanomethylene-
2,4,5,7-tetranitrofluorenone, tetranitrocarbazole chloranil, 2,3-dichloro-5,6-dicyanobenzoquinone, 2,
Examples include 4,7-trinitro-9,10-phenanthrenequinone, tetrachlorophthalic anhydride, tetracyanoethylene, and tetracyanoquinodimethane. Compounds that transport holes include compounds having an electron donating group, such as those disclosed in US Pat. No. 3,567,450,
49-35702, triphenylamine derivatives disclosed in West German Patent (DAS) 1110518, etc., U.S. Patent No. 3542544, Japanese Patent Publication No. 45-555, Japanese Patent Publication No. 1983-93224
Polyarylalkane derivatives disclosed in JP-A-52-72231, JP-A-49-105537, JP-A-52-4188, etc., U.S. Pat. No. 3,717,462, JP-A-54-59143 ( Corresponding to U.S. Patent No. 4150987), JP-A-55-52063, JP-A-Sho 55
-52064, JP-A-55-46760, JP-A-55-85495,
There are hydrazone derivatives disclosed in Japanese Patent Application No. 55-85495 and Japanese Patent Application No. 56-33832. Two or more types of these charge transport materials may be used in combination depending on the case. In addition, the photoreceptor obtained in the above manner has the following properties:
An adhesive layer or barrier layer can be provided between the conductive support and the photosensitive layer, if necessary. Materials used for these layers include polyamide, nitrocellulose, aluminum oxide, etc.
The thickness of these layers is preferably 1 μm or less. The electrophotographic photoreceptor of the present invention has been described in detail above, and the electrophotographic photoreceptor of the present invention generally has the characteristics of high sensitivity and excellent durability. The electrophotographic photoreceptor of the present invention can be widely applied to electrophotographic copying machines, as well as photoreceptors for printers using lasers and blown tubes as light sources. The photoconductive composition containing the disazo compound of the present invention can be applied as a photoconductive layer of an image pickup tube of a video camera, or on the entire surface of a one-dimensional or two-dimensional array of semiconductor circuits for performing known signal transfer or scanning. It can be used as a photoconductive layer of a solid-state image sensor having a light-receiving layer (photoconductive layer). Also, AKGhosh Tom Feng.J.Appl.Phys.49
(12) 5982 (1978), it can also be used as a photoconductive layer in solar cells. EXAMPLES Next, the present invention will be specifically explained using Examples, but the present invention is not limited to the Examples. In the examples, "parts" indicate "parts by weight." Example 1 1 part of disazo compound (1), 5 parts of 4,4'-bis(diethylamino)-2,2'-dimethyltriphenylmethane, and polycarbonate 5 of bisphenol A
95 parts of dichloromethane, pulverized and mixed in a ball mill to prepare a solution, and coated with indium oxide on the surface of a conductive transparent support (100 μm polyethylene terephthalate film) using a wire round rod. with a vapor-deposited film.
Coated on surface resistance (10 ³ Ω) and dried to a thickness of approximately 8.4μ
An electrophotographic photoreceptor having a single-layer electrophotographic photosensitive layer of m was prepared. This electrophotographic photoreceptor was tested with +
It was charged to +420V by a 5KV corona discharge, and then a tungsten lamp with a color temperature of 3000〓 was used to irradiate the surface with light at 4 lux.
The time required for the surface potential to attenuate to half of the initial surface potential was determined, and the half-reduction exposure amount E ₅₀ (Lux.sec) was measured and found to be 6.6 (Lux.sec). The E ₅₀ value after repeating the two steps of charging and exposure 3000 times also hardly changed. Examples 2 to 13 Disazo compounds (2), (3), (4), (5), (11), (13), (15), respectively in place of disazo compound (1),
An electrophotographic photoreceptor having a single layer structure was prepared in the same manner as in Example 1 except that (25), (26), (46), (55), and (59) were used. The half-reduction exposure due to positive charging was measured, and the values shown in Table 2 were obtained.

[Table] Example 14 After dispersing 5 g of disazo compound (1) and 2 g of polyvinyl butyral resin (degree of butyralization 63 mol%) in 100 ml of ethanol in a Pall mill for 20 hours, using a wire round rod, It was coated on a conductive transparent support (a 100 μm polyethylene terephthalate film with a vapor-deposited aluminum film on the surface; surface electrical resistance: 10 ³ Ω) and dried to form a charge generation layer with a thickness of 1 μm. Next, put the charge generation layer on top of p-(diphenylamino)
Benzaldehyde N'-methyl-N'-phenylhydrazone A solution of 2 parts of polycarbonate and 4 parts of bisphenol A dissolved in 60 parts of dichloromethane was applied using a wire round rod and dried to a thickness of 8 μm.
An electrophotographic photoreceptor having a two-layer electrophotographic photosensitive layer was prepared by forming a charge transport layer of m. This photoreceptor is subjected to -5KV corona discharge-
After charging to 400V, the half-decrease exposure was measured.
_E50 was 5.8 (lux.sec). Examples 15-24 Disazo compounds (6), (7), (8), (12), (16), (41), (45) were used instead of disazo compound (1), respectively.
),
An electrophotographic photoreceptor with a two-layer structure was prepared in the same manner as in Example 14 except that (48), (51), and (60) were used.
_E50 was measured. The results are shown in Table 3.

[Table] Example 25 As a charge transport layer, p-(diphenylamino)
Instead of benzaldehyde N'-methyl-N'-phenylhydrazone, 2,4,7-trinitro-
A layer with a thickness of 12 μm was formed on a charge generation layer of 1 μm in the same manner as in Example 11 except that 4 parts of 9-fluorenone was used.
A charge transport layer was formed. When this electrophotographic photoreceptor was charged to +600V by +5KV corona discharge and _E50 was measured,
It was 7.2 (lux・sec). Examples 26 to 29 Electrophotography of a two-layer structure in the same manner as in Example 25 except that disazo compounds (9), (42), (52), and (61) were used instead of disazo compound (1), respectively. A photoreceptor was prepared and _E50 was measured. The results are shown in Table 4.

[Table] Example 30 Add 1 part of disazo compound (1) and 1 part of bisphenol A polycarbonate to 25 parts of dichloromethane, grind and mix in a ball mill to prepare a liquid, and apply this coating liquid to a wire round. Coating on a conductive transparent support (a 100 μm polyethylene terephthalate film with a vapor-deposited indium oxide film on the surface; surface resistance: 10 ³ Ω) using a rod.
After drying, an electrophotographic photoreceptor having a single-layer electrophotographic photosensitive layer with a thickness of about 9 μm was obtained. After this electrophotographic photoreceptor was charged to +450V by +5KV corona discharge, _E50 was measured.
It was 9.8 (lux・sec). Examples 31 to 34 Single-layer electrophotographic photosensitive treatment was carried out in the same manner as in Example 27, except that disazo compounds (10), (43), (56), and (62) were used instead of disazo compound (1), respectively. A body was prepared and the _E50 was measured. The results are shown in Table 5.

【table】 [Brief explanation of drawings]

FIG. 1 is an infrared absorption spectrum (KBr method) of the disazo compound (15) of the present invention.

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor comprising an electrophotographic photosensitive layer containing a disazo compound represented by the following general formula [1]. In the above general formula [1], A represents [Formula] [Formula] [Formula] [Formula] or [Formula], and X is fused with the benzene ring in the above formula to which the hydroxy group and Y are bonded aromatic rings such as naphthalene rings, anthracene rings, or indole rings,
Represents an atomic group necessary to form a heterocycle (any ring may be substituted or unsubstituted) such as a carbazole ring, benzocarbazole ring, or dibenzofuran ring, and Y represents [Formula] or -COOR ⁵ ; R ¹ represents an alkyl group having 1 to 8 carbon atoms, a phenyl group, or a substituted product thereof, R ² represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms,
Carbamoyl group, carboxyl group, carbon number 1-10
represents an alkoxycarbonyl group, an aryloxycarbonyl group having 6 to 12 carbon atoms, or a substituted or unsubstituted amino group, and R ³ and R ⁵ represent an alkyl group having 1 to 8 carbon atoms, a phenyl group, a naphthyl group, a dibenzofura group. represents a nyl group, a carbazolyl group, or a substituted product thereof, R ⁴ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms,
Represents a phenyl group or a substituted product thereof.