JPH0210410B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a photoreceptor, and more particularly to a novel electrophotographic photoreceptor having a photosensitive layer containing an azo compound. (Prior Art) Conventionally, inorganic photoreceptors having a photosensitive layer mainly composed of an inorganic photoconductive compound such as selenium, zinc oxide, or cadmium sulfide have been widely used as photoreceptors. However, these are not necessarily satisfactory in terms of sensitivity, thermal stability, moisture resistance, durability, etc. For example, when selenium crystallizes, its properties as a photoreceptor deteriorate, making it difficult to manufacture.Also, selenium crystallizes due to heat, fingerprints, etc., and its performance as a photoreceptor deteriorates. In addition, cadmium sulfide has problems with moisture resistance and durability, and zinc oxide has problems with durability, etc. In order to overcome these drawbacks of inorganic photoreceptors, research and development have been actively conducted in recent years on organic photoreceptors having photosensitive layers containing various organic photoconductive compounds as main components. For example, in Japanese Patent Publication No. 50-10496, poly-N-vinylcarbazole and 2,4,7-
There is a description of an organic photoreceptor having a photosensitive layer containing trinitro-9-fluorenone. However, this photoreceptor is not necessarily satisfactory in sensitivity and durability. In order to improve these drawbacks, attempts have been made to develop organic photoreceptors with higher performance by assigning the carrier generation function and the carrier transport function to different substances. Many studies have been conducted on such so-called functionally separated electrophotographic photoreceptors because each material can be selected from a wide range and a photoreceptor with arbitrary performance can be produced relatively easily. Ta. Many compounds have been proposed as carrier generating substances for such functionally separated electrophotographic photoreceptors. As an example of using an inorganic compound as a carrier generating substance, for example,
-There is amorphous selenium described in Publication No. 16198,
Although this is used in combination with an organic photoconductive compound, the drawback that the carrier generation layer made of amorphous selenium crystallizes due to heat and deteriorates the properties as a photoreceptor has not been improved. Furthermore, many electrophotographic photoreceptors using organic dyes or organic pigments as carrier generating substances have been proposed. For example, as an electrophotographic photoreceptor containing a bisazo compound or a trisazo compound in the photosensitive layer, JP-A-54-12742, JP-A-57-74746, JP-A-53-95033, etc. have already been published. It is publicly known. However, these bisazo compounds or trisazo compounds are not necessarily satisfactory in terms of sensitivity, residual potential, or stability during repeated use, and the selection range of carrier transport materials is also limited. It does not fully satisfy the wide range of process requirements. Furthermore, in recent years, Ar laser has been used as a light source for photoreceptors.
Gas lasers such as He--Ne lasers and semiconductor lasers are beginning to be used. A characteristic of these lasers is that they can be turned on and off in a time-series manner, making them particularly promising as light sources for copiers with image processing functions, such as Intelligent Cobia, and printers for computer output. Among these, semiconductor lasers are attracting attention because their nature does not require an electrical signal/optical signal conversion element such as an acousto-optic element, and because they can be made smaller and lighter. However, this semiconductor laser has a low output compared to a gas laser,
Furthermore, since the oscillation wavelength is long (approximately 780 nm or more), the spectral sensitivity of conventional photoreceptors is higher on the short wavelength side, and as it is, it is impossible to use them as photoreceptors using semiconductor lasers as light sources. (Object of the Invention) An object of the present invention is to provide a photoreceptor containing a specific disazo compound that is stable to heat and light and has excellent carrier generation ability. Another object of the present invention is to provide an electrophotographic photoreceptor with high sensitivity, low residual potential, and excellent durability whose characteristics do not change even after repeated use. Still another object of the present invention is to provide an electrophotographic photoreceptor containing a disazo compound that can effectively act as a carrier generating substance even in combination with a wide variety of carrier transport substances. Still another object of the present invention is to provide a photoreceptor having sufficient practical sensitivity even to long wavelength light sources such as semiconductor lasers. Still other objects of the present invention will become apparent from the description in the specification. (Structure of the Invention) As a result of intensive research to achieve the above object, the present inventors discovered that a disazo compound represented by the following general formula [] can function as an active ingredient of a photoreceptor, and the present invention This is the completed version. General formula [] In the formula, A is a substituted or unsubstituted alkyl group (e.g., ethyl group, propyl group, bentyl group, methoxyethyl group, hydroxyethyl group, benzyl group, phenethyl group, etc.) or a substituted or unsubstituted aryl group (e.g., phenyl group, p-methylphenyl group, 2,4
-dimethylphenyl group, methoxyphenyl group, chlorophenyl group, etc.), and R represents a hydrogen atom, an alkyl group, (e.g., methyl group, ethyl group, etc.) or an alkoxy group (e.g., methoxy group, ethoxy group, etc.)
or halogen atoms (e.g. fluorine, chlorine, bromine)
represents. C _p is

【formula】

【formula】

[expression] or

[Formula], Y is a substituted/unsubstituted carbamoyl group (

[Formula]), substituted and unsubstituted sulfamoy group (

[Formula]), R ₄ : hydrogen atom, substituted/unsubstituted alkyl group having 1 to 4 carbon atoms, substituted/unsubstituted aralkyl group, substituted/unsubstituted phenyl group, R ₅ : hydrogen atom , substituted/unsubstituted alkyl groups having 1 to 4 carbon atoms, substituted/unsubstituted aromatic carbocyclic groups (e.g., substituted/unsubstituted phenyl groups, substituted/unsubstituted naphthyl groups, substituted/unsubstituted anthryl groups) etc.), or a substituted/unsubstituted aromatic heterocyclic group (for example, a substituted/unsubstituted carbazolyl group, a substituted/unsubstituted dibenzofuryl group, etc.). Substituents for these groups include, for example, carbon atoms with 1
~4 substituted/unsubstituted alkyl groups (e.g. methyl group, ethyl group, isopropyl group, tertiary butyl group,
trifluoromethyl group, etc.), substituted/unsubstituted aralkyl groups (e.g., benzyl group, phenethyl group, etc.), halogen atoms (chlorine atom, bromine atom, fluorine atom, iodine atom), substituted/unsubstituted aralkyl groups with 1 to 4 carbon atoms. Substituted alkoxy groups (e.g. methoxy, ethoxy, isopropoxy, tertiary butoxy, 2-chloroethoxy, etc.), hydroxy groups, substituted/unsubstituted aryloxy groups (e.g. p-chlorophenoxy, 1- (naphthoxy group, etc.), acyloxy group (e.g., acetyloxy group, p-cyanobenzoyloxy group, etc.), carboxy group, its ester group (e.g., ethoxycarbonyl group, m-bromophenoxycarbonyl group, etc.), carbamoyl group (e.g., aminocarbonyl group, tertiary butylaminocarbonyl group, anilinocarbonyl group, etc.), acyl group (e.g., acetyl group, o-nitrobenzoyl group, etc.), sulfo group, sulfamoyl group (e.g., aminosulfonyl group, tertiary butylaminosulfonyl group, p-tolylaminosulfonyl group, etc.),
Preferred examples include amino group, acylamino group (e.g., acetylamino group, benzoylamino group, etc.), sulfonamide group (e.g., methanesulfonamide group, p-toluenesulfonamide group, etc.), cyano group, nitro group, etc. is a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms (e.g., methyl group,
ethyl group, isopropyl group, n-butyl group, trifluoromethyl group, etc.), halogen atom (chlorine atom,
Bromine atom, fluorine atom, iodine atom), carbon number 1-4
Substituted/unsubstituted alkoxy groups (eg, methoxy group, ethoxy group, tertiary butoxy group, 2-chloroethoxy group, etc.), cyano group, and nitro group. Z is an atomic group necessary to form a substituted/unsubstituted aromatic carbocycle or a substituted/unsubstituted aromatic heterocycle, and specifically, for example, a substituted/unsubstituted benzene ring, a substituted/unsubstituted aromatic heterocycle, etc. Represents an atomic group forming an unsubstituted naphthalene ring, a substituted/unsubstituted indole ring, a substituted/unsubstituted carbazole ring, etc. Examples of substituents for the atomic group forming these rings include a series of substituents such as those listed as substituents for R ₄ and R ₅ , but halogen atoms (chlorine, bromine, fluorine, etc.) are preferred. atom, iodine atom), a sulfo group, and a sulfamoyl group (eg, an aminosulfonyl group, a p-tolylaminosulfonyl group, etc.). R ₁ is a hydrogen atom, a substituted or unsubstituted alkyl group,
Substituted/unsubstituted amino groups, carboxy groups, ester groups thereof, substituted/unsubstituted carbamoyl groups, and cyano groups, preferably hydrogen atoms, substituted/unsubstituted alkyl groups having 1 to 4 carbon atoms (for example, methyl groups) ,
ethyl group, isopropyl group, tertiary butyl group, trifluoromethyl group, etc.), and cyano group. A' is a substituted or unsubstituted aryl group, preferably a substituted or unsubstituted phenyl group, and the substituents for these groups include a series of substituents such as those listed as substituents for R ₄ and R ₅ . Preferably, halogen atoms (chlorine atom, bromine atom, fluorine atom, iodine atom), substituted or unsubstituted alkyl groups having 1 to 4 carbon atoms (for example, methyl group, ethyl group, isopropyl group, tertiary butyl group, trifluoromethyl group, etc.), and substituted/unsubstituted alkoxy groups having 1 to 4 carbon atoms (eg, methoxy group, ethoxy group, isopropoxy group, tertiary butoxy group, 2-chloroethoxy group). R ₂ and R ₃ represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group, but preferably have 1 to 1 carbon atoms.
4 substituted/unsubstituted alkyl groups (e.g., methyl group, ethyl group, isopropyl group, tertiary butyl group,
trifluoromethyl group, etc.), substituted/unsubstituted phenyl group (eg, phenyl group, p-methoxyphenyl group, m-chlorophenyl group, etc.). That is, in the present invention, by using the disazo compound represented by the above general formula [] as a photoconductive substance constituting the photosensitive layer of the photoreceptor, it is stable against heat and light, which is the object of the present invention. In addition, we have developed an excellent photoreceptor that has excellent electrophotographic properties such as charge retention, sensitivity, and residual potential, and has little fatigue change even after repeated use, and has sufficient sensitivity even in the long wavelength region of 780 nm or more. can be created. Among the disazo compounds represented by the above general formula [] used in the present invention, those represented by the following general formula [] are preferred. General formula [] Specific examples of the disazo compounds useful in the present invention represented by the general formulas [] and [] include those having the following structural formulas,
The disazo compound of the present invention is not limited thereby. A-(1)-(33) General formula [] (Formula [] and R in Table (A) below, the number indicates the bonding position of the substituent R.)

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

[Table] These compounds can be synthesized by a combination of conventional and well-known methods. A synthesis example is shown below. Synthesis Example 1 Synthesis of Exemplified Compound A-(2) 1 Synthesis of Intermediate Dinitrophenothiazine Method of C. Bodea. M. Raileau (Chem. Abst.
Vol. 54, 22657g (1960)). That is, 25 g of phenothiazine is mixed with 600 g of chloroform.
ml and 50 ml of glacial acetic acid, and 25 g of sodium nitrite was added little by little over 1 hour. After the addition, the mixture was further stirred for 2 hours, and the resulting crystals were collected by filtration and thoroughly washed with methanol and then water. This product was recrystallized from DMF (N,N-dimethylformamide) to obtain 14 g of the intermediate dinitrophenothiazine. (Yield 38.6%) 2 Synthesis of intermediate N-P-tolyldinitrophenothiazine 8.7 g of dinitrophenothiazine and 10 g of p-iodotoluene were mixed with 50 ml of nitrobenzene, and to this was added 8 g of potassium carbonate and 0.5 g of copper powder. 210℃~
The reaction was carried out at 220°C for 10 hours. After the reaction, nitrobenzene and remaining p-iodotoluene were distilled off by steam distillation, and then the crude crystals were collected by filtration.
To this was added 1.5 g of chloroform and extracted while hot. After filtering the extract through 50 g of silica gel (200 mesh), the filtrate was evaporated to dryness. The residue was suspended and washed with a small amount of ethyl acetate, and then thoroughly washed in 50 ml of methanol, 3 g of sodium hydroxide, and 5 ml of water. Further washing was performed with water and then with methanol to obtain 5.1 g of the target intermediate N-p-tolyldinitrophenothiazine red crystals. Yield 45% Melting point 185-188
℃. 3 Intermediate Synthesis of 2,7-diamino-10-tolylphenothiazine exemplary compound-(2) 3.8 g of N-p-tolyldinitrophenothiazine
was suspended in 150 ml of concentrated hydrochloric acid, 40 g of stannous chloride (dihydrate) was added thereto, and the mixture was heated under reflux for 3 hours.
After cooling, the crystals were filtered and washed with dilute hydrochloric acid to obtain 2,7-
A diamino-10-tolylphenothiazine-tin complex was obtained. (Melting point 195-200℃) Add the entire amount of the above diamino compound-tin complex to 20 ml of hydrochloric acid water.
A solution prepared by dissolving 1.5 g of sodium nitrite in 10 ml of water was added dropwise at -5°C. After the completion of the dropwise addition, stir at the same temperature for 30 minutes, immediately filter, and add phosphorus ammonium hexafluoride 10 to the obtained filtrate.
The resulting crystals were collected by filtration to obtain tetrazonium hexafluorophosphate. These crystals were dissolved in 100 ml of N,N-dimethylformamide and used as a dropwise solution for the next coupling reaction. Next, 7.0 g of 2-hydroxy-3-(4-methoxyphenylcarbamoyl)-benzo[a]carbazole (naphthol AS-SG, manufactured by Hoechst) and 10 g of triethanolamine were dissolved in 300 ml of N,N-dimethylformamide. The above-mentioned tetrazonium salt solution was added dropwise to the solution while cooling with ice at 5°C. After further stirring at the same temperature for 2 hours, the mixture was allowed to stand overnight at room temperature, and the resulting crystals were collected by filtration. The crystals were washed twice with 300 ml of N,N-dimethylformamide.
After washing twice with acetone, the mixture was dried to obtain 4.8 g of Exemplified Compound A-(2). Yield 43% (from dinitro form) This compound was confirmed by elemental analysis. (Chemical formula is C ₆₇ H ₄₇ H ₉ O ₆ S)

[Table] Synthesis Example 2 (Synthesis of Exemplary Compound A-(3)) 1 Synthesis of Intermediate N-ethyldinitrophenothiazine 5.8 g of dinitrophenothiazine was added to 200 ml of acetone.
To this was added 8.4 g of potassium carbonate and 7.2 g of diethyl sulfate, and the mixture was heated under reflux for 10 hours. After the reaction, 100ml of acetone was distilled off, then 100ml of water was added,
The crystals were collected by filtration. Wash with water and add 100 methanol
Sufficiently in a mixture of 20ml of water and 5g of sodium hydroxide.
After suspension washing and removing unreacted raw materials, 5.8 g of N-ethyldinitrophenothiazine was obtained. (melting point
215-216℃ yield 91%) 2 Synthesis of intermediate 10-ethyl-2,7-diaminophenothiazine Dissolve 6.34 g of N-ethyldinitrophenothiazine in 100 ml of N,N-dimethylformamide.
Add 10g of iron, 10ml of water, and 2ml of hydrochloric acid to this, and add 105~
Heated at 110°C for 1 hour. After the reaction, a suspension of 3 g of sodium bicarbonate in 15 ml of water was added, and the mixture was filtered while hot. Filter with 500ml of ice water and 10% sodium hydroxide solution.
Added 40ml. The resulting crystals were collected by filtration, washed with water, and then evaporated to dryness with the addition of hydrochloric acid to give a hydrochloride. Yield 3g (yield 42% as trihydrochloride) Melting point 250
°C (decomposition) 3 Synthesis of Exemplified Compound A-(3) Disperse 3.68 g of the above 10-ethyl-2,7-diaminophenothiazine hydrochloride in 10 ml of hydrochloric acid and 60 ml of water.
A solution prepared by dissolving 1.7 g of sodium nitrite in 10 ml of water was added dropwise to this at -5°C. After the dropwise addition was completed, the mixture was stirred at the same temperature for 10 minutes and immediately filtered. 10 g of ammonium hexafluorophosphate was added to the resulting filtrate, and the resulting crystals were collected by filtration to obtain tetrazonium hexafluorophosphate. Ta. This crystal is N,
It was dissolved in 100 ml of N-dimethylformamide to obtain a dropwise solution for the next coupling reaction. 5.27 g of 2-hydroxy-3-naphthoic acid anilide (naphthol AS) was dissolved in 200 ml of N,N-dimethylformamide, and 6.0 g of triethanolamine was added thereto. Next, this solution was cooled to 5° C., and the above-mentioned dropwise solution was added thereto while stirring vigorously. After the dropwise addition was completed, the mixture was stirred for about 1 hour, then warmed to room temperature and left overnight. The resulting crystals were collected by filtration and diluted twice with 500 ml of dimethylformamide.
After washing once with acetone (No. 1) and drying, 3.1 g of a blue compound was obtained. Yield: 19% This compound was confirmed by elemental analysis. Elemental analysis results (chemical formula is C ₄₈ H ₃₅ O ₄ SN ₇ )

[Table] The disazo compound of the present invention has excellent photoconductivity, and when producing an electrophotographic photoreceptor using it, the disazo compound of the present invention is dispersed in a binder on a conductive support. It can be manufactured by providing a photosensitive layer. Another method is to use the disazo compound of the present invention as a carrier-generating substance that takes advantage of its particularly excellent carrier-generating ability among its photoconductivity properties, and to use it together with a carrier-transporting substance that can effectively act in combination with the disazo compound. It is also possible to make a so-called functionally separated electrophotographic photoreceptor, such as a laminated type or a dispersed type. Furthermore, the disazo compound used in the present invention can be used alone or in combination of two or more of the disazo compounds represented by the above general formula [], or in combination with other disazo or triazo compounds. good. Various mechanical configurations of electrophotographic photoreceptors are known, and the electrophotographic photoreceptor of the present invention can take any of these forms. Usually, the configuration is as shown in FIGS. 1 to 6. 1 and 3, a carrier generation layer 2 mainly composed of the above-mentioned disazo compound is provided on a conductive support 1,
A photosensitive layer 4 is provided which is a laminate with a carrier transport layer 3 containing a carrier transport substance as a main component. As shown in FIGS. 2 and 4, this photosensitive layer 4 may be provided via an intermediate layer 5 provided on a conductive support. When the photosensitive layer 4 has a two-layer structure in this manner, an electrophotographic photoreceptor having the most excellent electrophotographic properties can be obtained. Furthermore, in the present invention,
As shown in FIGS. 5 and 6, the carrier generating substance 7 is replaced with a layer 6 containing a carrier transporting substance as a main component.
A conductive support 1 has a photosensitive layer 4 dispersed therein.
It may be provided directly thereon or via the intermediate layer 5. When the disazo compound of the present invention is used as a carrier generating substance, examples of the carrier transporting substance used in combination with the disazo compound include electron-accepting substances that easily transport electrons such as trinitrofluorenone or tetranitrofluorenone, as well as poly-N-
Polymers having heterocyclic compounds in their side chains such as vinylcarbazole, triazole derivatives, oxadiazole derivatives, imidazole derivatives, pyrazoline derivatives, polyarylalkane derivatives, phenylenediamine derivatives, hydrazone derivatives, amino-substituted alcone derivatives , triarylamine derivatives, carbazole derivatives, stilbene derivatives, and other electron-donating substances that easily transport holes, but the carrier transport substance used in the present invention is not limited to these. The carrier generation layer 2 constituting the photosensitive layer 4 having a two-layer structure is the conductive support 1 or the carrier transport layer 3.
It can be formed directly thereon or, if necessary, with an intermediate layer such as an adhesive layer or a barrier layer provided thereon, for example, by the following method. M-1 A method of applying a solution in which a disazo compound is dissolved in a suitable solvent, or a solution in which a binder is added and mixed as necessary. M-2 A method in which a disazo compound is made into fine particles in a dispersion medium using a ball mill, a homomixer, etc., and a binder is added as necessary to mix and disperse the resulting dispersion and then applied. Examples of the solvent or dispersion medium used for forming the carrier generation layer include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N,N-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone, benzene, Toluene, xylene, chloroform,
Examples include 1,2-dichloroethane, dichloromethane, tetrahydrofuran, dioxane, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide and the like. When using a binder in the carrier generation layer or carrier transport layer, any binder can be used, but it is preferable to use a film-forming polymer that is hydrophobic, has a high dielectric constant, and is electrically insulating. . Examples of such high molecular weight polymers include, but are not limited to, the following. P-1 Polycarbonate P-2 Polyester P-3 Methacrylic resin P-4 Acrylic resin P-5 Polyvinyl chloride P-6 Polyvinylidene chloride P-7 Polystyrene P-8 Polyvinyl acetate P-9 Styrene-butadiene copolymer P- 10 Vinylidene chloride-acrylonitrile copolymer P-11 Vinyl chloride-vinyl acetate copolymer P-12 Vinyl chloride-vinyl acetate-maleic anhydride copolymer P-13 Silicone resin P-14 Silicone-alkyd resin P-15 Phenol -Formaldehyde resin P-16 Styrene-alkyd resin P-17 Poly-N-vinylcarbazole P-18 Polyvinyl butyral These binders can be used alone or as a mixture of two or more. The thickness of the carrier generation layer 2 thus formed is preferably 0.01 μm to 20 μm, more preferably 0.05 μm to 5 μm. Further, when the carrier generation layer or the photosensitive layer is a dispersed type, the particle size of the azo compound is preferably 5 μm or less, more preferably 1 μm or less. The conductive support used in the electrophotographic photoreceptor of the present invention is a metal plate including an alloy, a metal drum or a conductive polymer, a conductive compound such as indium oxide, aluminum including an alloy, palladium, gold, etc. Examples include paper, plastic film, etc. that have been made conductive by coating, vapor depositing, or laminating a thin metal layer. As an intermediate layer such as an adhesive layer or a barrier layer, in addition to the polymer used as the binder, an organic polymer material such as polyvinyl alcohol, ethyl cellulose, or carboxymethyl cellulose, or aluminum oxide is used. The electrophotographic photoreceptor of the present invention has the above-mentioned structure, and as is clear from the examples described later,
It has excellent charging characteristics, sensitivity characteristics, and image forming characteristics, and especially shows little fatigue deterioration even when used repeatedly, and has excellent durability. Hereinafter, the present invention will be specifically explained in Examples,
This does not limit the embodiments of the present invention. (Example) Example 1 2 g of Exemplified Compound A-(3) and 2 g of polycarbonate resin "Panlite L-1250" (manufactured by Tabito Kasei Co., Ltd.) were added to 110 ml of 1,2-dichloroethane, and dispersed in a ball mill for 12 hours. . This dispersion was applied onto a polyester film on which aluminum was vapor-deposited so that the dry film thickness would be 1 μm to form a carrier generation layer, and then a carrier transport layer (formula K-(1) below) )6g of polycarbonate resin "Panlite L-1250" and 10g of polycarbonate resin "Panlite L-1250" dissolved in 110ml of 1,2-dichloroethane.
A carrier transport layer was formed by coating to a thickness of 15 μm, and an electrophotographic photoreceptor of the present invention was prepared. The photoreceptor obtained as described above was subjected to the following temporal evaluation using an electrostatic paper tester model SP-428 manufactured by Kawaguchi Electric Seisakusho Co., Ltd. Charging voltage - After charging at 6KV for 5 seconds, leave in the dark for 5 seconds, then irradiate with halogen lamp light so that the illumination intensity on the photoreceptor surface is 35 lux, and the amount of exposure required to attenuate the surface potential by half. (Half-reduced exposure amount) E1/2 was determined. Also
The surface potential (residual potential) V _R after exposure with an exposure amount of 30 lux·sec was determined. Furthermore, similar measurements were repeated 100 times. The results are shown in Table 1.

[Table] Comparative Example 1 A comparative photoreceptor was prepared in the same manner as in Example 1, except that the following disazo compound (G-1) was used as a carrier generating substance. Regarding this electrophotographic photoreceptor for comparison, Example 1
When measurements were carried out in the same manner as above, the results shown in Table 2 were obtained.

[Table] As is clear from the above results, the electrophotographic photoreceptor of the present invention is extremely superior in sensitivity, residual potential, and repetition stability compared to the comparative electrophotographic photoreceptor. Example 2 A layer of vinyl chloride-vinyl acetate-maleic anhydride copolymer "Eslec MF-10" (manufactured by Sekisui Chemical Co., Ltd.) was placed on a conductive support made of aluminum foil laminated on a polyester film.
A 0.05 μm intermediate layer is provided, and exemplified compound A is placed on top of the intermediate layer.
2 g of -(9) was mixed with 110 ml of 1,2-dichloroethane and dispersed in a ball mill for 24 hours. The dispersion was applied to a dry film thickness of 0.5 μm to form a carrier generation layer. On this carrier generation layer, 6 g of 4-methoxytriphenylamine and 10 g of methacrylic resin "Acrypet" (manufactured by Mitsubishi Rayon Co., Ltd.)
A carrier transport layer was formed by coating a solution obtained by dissolving 1,2-dichloroethane (g) in 70 ml of 1,2-dichloroethane so that the film thickness after drying was 10 μm, thereby producing an electrophotographic photoreceptor of the present invention. When the same measurements as in Example 1 were carried out on this electrophotographic photoreceptor, E1/2=
The result was 2.5lux·sec, V _R =OV. Example 3 On the conductive support provided with the intermediate layer used in Example 2, a 1% ethylenediamine solution of Exemplary Compound A-(29) was applied to a dry film thickness of 0.3 μm, and a carrier was applied. A generation layer was formed. then on top of that 6 g of the above compound (K-2) and 10 g of polyester resin "Vylon 200" (manufactured by Toyobo Co., Ltd.)
-Dissolved in 70 ml of dichloroethane and applied this solution to a dry film thickness of 12 μm to form a carrier transport layer, thereby producing an electrophotographic photoreceptor of the present invention. The same measurements as in Example 1 were performed on this electrophotographic photoreceptor, and the results shown in Table 3 were obtained.

[Table] Example 4 A carrier generation layer was formed in the same manner as in Example 3 except that Exemplified Compound A-(29) was replaced with Exemplified Compound A-(11). on top of this 6 g of compound (K-3) and 10 g of polycarbonate "Panlite L-1250" (manufactured by Obito Kasei Co., Ltd.) were mixed in 1,
A carrier transport layer was formed by coating a solution dissolved in 70 ml of 2-dichloroethane so that the film thickness after drying was 10 μm, thereby producing an electrophotographic photoreceptor of the present invention. Regarding this electrophotographic photoreceptor, measurements were performed in the same manner as in Example 1. E = 3.1 lux・sec
and V _R =OV. Example 5 A 0.05 μm thick intermediate layer made of vinyl chloride-vinyl acetate-maleic anhydride copolymer "Eslec MF-10" (manufactured by Sekisui Chemical Co., Ltd.) was provided on the surface of an aluminum drum with a diameter of 100 mm, and then 4 g of Exemplified Compound (2) was mixed with 400 ml of 1,2-dichloroethane, and a dispersion liquid was dispersed for 24 hours using a ball mill dispersion machine, and the resulting dispersion was applied so that the film thickness after drying was 0.6 μm.
A carrier generation layer was formed. Furthermore, on top of this, 30g (compound K-4 below) and polycarbonate resin "Corpilon S-1000"
(manufactured by Mitsubishi Gas Chemical Co., Ltd.) 50g and 1,2-dichloroethane A carrier transport layer was formed by dissolving the solution in 400 ml and coating it to a film thickness of 13 μm after drying, thereby producing a drum-shaped electrophotographic photoreceptor. The photoreceptor created in this way was installed in a modified electrophotographic copying machine "U-Bix V2" (manufactured by Konishiroku Photo Industry Co., Ltd.), and images were copied with high contrast, true to cost, and clear copies. Got the image. Moreover, this did not change even after repeating this 10,000 times. Comparative Example 2 A drum-shaped comparative photoreceptor was prepared in the same manner as in Example 5, except that the exemplified compound A-(2) in Example 5 was replaced with an azo compound (G-2) represented by the following structural formula. When the copied images were evaluated in the same manner as in Example 5, only images with a lot of fog were obtained. Furthermore, as copying was repeated, the contrast of the copied image decreased, and after 2000 repetitions, almost no copied image could be obtained. Example 6 On the surface of an aluminum drum with a diameter of 100 mm,
An intermediate layer with a thickness of 0.05 μm made of vinyl chloride-vinyl acetate-maleic anhydride copolymer "Eslec MF-10 (manufactured by Sekisui Chemical Co., Ltd.) was provided, and 4 g of exemplified compound A-(2)) was placed thereon. 2-dichloroethane 400
ml and dispersed for 24 hours using a ball mill dispersion machine, the dispersion was applied to a dry film thickness of 0.5 μm to form a carrier generation layer. Furthermore, 30 g of 4-methyl-4'-styryltriphenylamine and 50 g of polycarbonate resin "Panlite L-1250" (manufactured by Teijin Kasei) were added to
The solution was dissolved in 400 ml of 2-dichloroethane and coated to a dry film thickness of 12 μm to form a carrier transport layer, thereby producing an electrophotographic photoreceptor on a drum. The spectral sensitivity of this photoreceptor at 780nm is
It was 1.09 μJ/cm ² (half exposure amount). Next, an actual photographic test was performed on this photoreceptor using an experimental machine equipped with a semiconductor laser (780 nm) that produced a laser light intensity of 0.85 mw on the photoreceptor surface. After the surface of the photoreceptor was charged to -6 kV, it was exposed to laser light and reverse development was carried out at a bias voltage of -350 V. A good image without fogging was obtained. Moreover, this did not change even after repeating this 10,000 times. Example 7 In place of Exemplified Compound A-(2) in Example 6,
A drum-shaped photoreceptor was obtained in the same manner except that Exemplified Compound A-(1) was used. The spectral sensitivity of each photoreceptor at 780nm is
It was 1.30 μJ/cm ² (half exposure amount). The results of a live-action test using an experimental machine gave good images with no fog, and there was no change even after 10,000 repeated tests.

[Brief explanation of drawings]

1 to 6 are sectional views showing examples of the mechanical structure of the electrophotographic photoreceptor of the present invention, and 1 to 7 in the figures represent the following, respectively. 1... Conductive support, 2... Carrier generation layer,
3... Carrier transport layer, 4... Photosensitive layer, 5... Intermediate layer, 6... Layer containing a carrier transport substance, 7
...Carrier generating substance.

Claims (1)

[Scope of Claims] 1. A photoreceptor comprising a photosensitive layer containing a disazo compound represented by the following general formula [] on a conductive support. General formula [] [In the formula, A represents a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, R represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom, Cp: [Formula] [Formula] [Formula] ] or [Formula], where Z: atomic group necessary to constitute a substituted/unsubstituted aromatic carbocycle or substituted/unsubstituted aromatic heterocycle, Y: substituted/unsubstituted carbamoyl group or substitution・
Unsubstituted sulfamoyl group, R ₁ : hydrogen atom, substituted/unsubstituted alkyl group, substituted/unsubstituted amino group, substituted/unsubstituted carbamoyl group, carboxy group and its ester group, or cyano group, A′: Substituted/unsubstituted aryl group, R ₂ and R ₃ represent substituted/unsubstituted alkyl group, substituted/unsubstituted aralkyl group, or substituted/unsubstituted aryl group. 2. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer contains a carrier transporting substance and a carrier generating substance, and the carrier generating substance is a disazo compound represented by the general formula [].