JP2803049B2 - Electrophotographic photoreceptor, electrophotographic apparatus provided with the electrophotographic photoreceptor, and facsimile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member containing a disazo pigment having a specific structure in a photosensitive layer, an electrophotographic apparatus provided with the electrophotographic photosensitive member, and a facsimile.

[0002]

2. Description of the Related Art Conventionally, inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have been widely used as electrophotographic photoreceptors. On the other hand, as an electrophotographic photoreceptor made of an organic photoconductive substance, poly-N-vinyl carbazo-
Photoconductive polymer represented by
Using a low-molecular organic photoconductive substance such as diethylaminophenyl) -1,3,4-oxadiazol;
Further, a combination of such an organic photoconductive substance with various dyes and pigments is known. An electrophotographic photoreceptor using an organic photoconductive substance has a good film-forming property and can be produced by coating, and thus has an advantage that an inexpensive photoreceptor with extremely high productivity can be provided. Further, there is an advantage that color sensitivity can be freely controlled by selecting a dye or a pigment to be used, and wide studies have been made so far. Particularly recently, the development of a function-separated type photoreceptor in which a charge generation layer containing an organic photoconductive dye or pigment and a charge transport layer containing the aforementioned photoconductive polymer or a low molecular weight organic photoconductive material are laminated. As a result, remarkable improvements have been made in sensitivity and durability, which have been regarded as disadvantages of conventional organic electrophotographic photosensitive members.

[0003] Azo pigments exhibit excellent photoconductivity, and compounds having various characteristics can be easily obtained by combining the azo component and the coupler component. See, for example,
JP-A-182748, JP-A-54-22834 and the like are already known. However, the electrophotographic photoreceptor using the conventional disazo pigment is not necessarily sufficient in terms of sensitivity and potential stability upon repeated use.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel photoconductive material, and to provide an electrophotographic photoreceptor having practically high sensitivity characteristics and stable potential characteristics when used repeatedly. Another object of the present invention is to provide an electrophotographic apparatus and a facsimile provided with the electrophotographic photosensitive member.

[0005]

According to the present invention, there is provided an electrophotographic photosensitive member having a photosensitive layer containing a disazo pigment represented by the following general formula (1) on a conductive support. General formula (1) Wherein A ₁ and A ₂ are the same or different and are pheno-
2 shows a coupler residue having a hydroxyl group.

Preferred examples of the coupler residue having a phenolic hydroxyl group represented by A ₂ and A ₂ include the residues represented by the following general formulas (2) to (7).

The general formula (2)

The general formula (3)

The general formula (4):

The general formula (5):

The general formula (6)

The general formula (7)

X in the general formulas (2), (3), (4) and (5) is a naphthalene ring, anthracene ring, carbazole ring which may be substituted with a benzene ring,
Y represents a residue necessary for forming a polycyclic aromatic ring or a heterocyclic ring such as a benzocarbazole ring or a dibenzofuran ring, and Y in the general formula (7) is a divalent aromatic hydrocarbon which may have a substituent. A divalent heterocyclic group containing a group or a nitrogen atom in the ring, specifically, o-phenylene, o-naphthylene,
Divalent groups such as perinaphthylene, 1,2-anthrylene, 3,4-pyrazoldiyl, 2,3-pyridinediyl, 4,5-pyridinediyl, 6,7-indazoldiyl and 6,7-quinolinediyl General formula (2)
R ₁ and R _{2 in} (3) represent a hydrogen atom, an alkyl group which may have a substituent, an aryl group, an aralkyl group or a heterocyclic group, and both R ₁ and R ₂ are nitrogen A cyclic amino group may be formed via an atom, and R ₃ in the general formulas (4) and (5) is a hydrogen atom, an alkyl group which may have a substituent, an aryl group, an aralkyl group or A heterocyclic group; R ₄ in the general formula (6) represents a hydrogen atom, an alkyl group which may have a substituent, an aryl group, an aralkyl group or a heterocyclic group; Is a group such as methyl, ethyl, propyl, specific examples of aryl groups such as phenyl, naphthyl and anthryl, aralkyl groups such as benzyl and phenethyl, and heterocyclic groups such as pyridyl, thienyl, carbazolyl, benzimidazolyl, Groups such as benzothiazolyl,
As a cyclic amino group containing a nitrogen atom in the ring, pyrrol,
Examples include pyrroline, pyrrolidine, pyrrolidone, indole, indoline, carbazole, imidazole, pyrazol, pyrazoline, oxazine, phenoxazine and the like. Further, as a substituent, fluorine, chlorine, iodine, halogen atoms such as bromine, methyl, ethyl, alkyl groups such as propyl, methoxy, alkoxy groups such as ethoxy,
Dimethylamino, alkylamino groups such as diethylamino, phenylcarbamoyl group, nitro group, cyano group, halomethyl groups such as trifluoromethyl and the like,
Z in the general formulas (2) and (4) represents an oxygen atom or a sulfur atom, and p is an integer of 0 or 1.

A ₁ and A _{2 in the} general formula (1)
Is the general formula (2), (3), (4) or (5),
A pigment using a coupler in which X in the formula is condensed with a benzene ring to form a benzocarbazole ring has an absorption region extending to near the near-infrared region, so that charge generation for a semiconductor laser is performed. It is also suitable as a material.

Further, the present invention comprises the electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer comprises at least two layers of a charge generation layer containing a disazo pigment represented by the general formula (1) and a charge transport layer.

Further, the present invention comprises an electrophotographic apparatus provided with the electrophotographic photoreceptor of the present invention.

Further, the present invention comprises an electrophotographic apparatus provided with the electrophotographic photoreceptor of the present invention and a facsimile having a receiving means for receiving image information from a remote terminal.

Next, typical specific examples of the disazo pigment represented by the general formula (1) of the present invention are shown in the following table, but the disazo pigment used in the present invention is not limited thereto. Illustrative pigments represent a specific structure by describing only the portions that change in the basic type.

Table 1 Table 2 Table 3 Table 4 Table 5 Table 6 Table 7 Table 8 Table 9 Table 10 Table 11 Table 12 Table 13 Table 14 Table 15 Table 16 Table 17

The disazo pigment represented by the general formula (1) is obtained by subjecting a corresponding diamine to tetrazotization by a conventional method, and coupling with a coupler in the presence of an alkali in an aqueous system, or converting a tetrazonium salt into a borofluoride or zinc chloride double salt. And then easily coupled with a coupler in an organic solvent such as N, N-dimethylformamide or dimethylsulfoxide in the presence of a base such as sodium acetate, triethylamine or N-methylmorpholine. it can.

When disazo pigments in which A ₁ and A ₂ in the general formula (1) are different couplers are synthesized, one coupler-1 is first added to 1 mol of the above-mentioned tetrazonium salt.
Moles and then the other coupler
Either 1.05 mol is synthesized by coupling, or one amino group of the diamine is protected with an acetyl group and the like is diazotized, and one of the couplers is coupled. And then diazotized again to couple the other coupler.

Synthesis Example (Synthesis of Pigment 1) 150 ml of water was added to a 300 ml beaker.
20 ml (0.23 mol) of concentrated hydrochloric acid Was added to 7.2 g (0.032 mol) and cooled to 0 ° C.
A solution prepared by dissolving 4.6 g (0.067 mol) of soda nitrite in 10 ml of water was added to the solution while maintaining the temperature at 2 ° C or lower.
It was dropped in 0 minutes. After stirring for 15 minutes, the mixture was filtered through carbon, and 10.5 g (0.00.0%) of sodium borofluoride was added to this solution.
(96 mol) in 90 ml of water was added dropwise with stirring, and the precipitated borofluoride was collected by filtration, washed with cold water, washed with acetonitrile, and dried at room temperature under reduced pressure. Yield 10.6 g, yield 78.1%

Next, 500 ml of DMF was placed in a 1 liter beaker, and 11.1 g of naphthol AS (0.
042 mol) was dissolved and the liquid temperature was cooled to 5 ° C., and 8.5 g (0.020 mol) of the previously obtained borofluoride was dissolved.
Then, 5.1 g (0.050 mol) of triethylamine was added dropwise over 5 minutes. After stirring for 2 hours, the precipitated pigment was collected by filtration, washed four times with DMF and three times with water, and then freeze-dried. Yield 10.7 g, 69.0% yield

Elemental analysis value C calculated value 71.3%, measured value 71.5% H calculated value 3.9%, measured value 3.9% N calculated value 14.5%, measured value 14.7%

The electrophotographic photosensitive member of the present invention has a photosensitive layer containing a disazo pigment represented by the general formula (1) on a conductive support. The form of the photosensitive layer may be any known form, but the photosensitive layer containing the disazo pigment represented by the general formula (1) is used as a charge generation layer, and the charge generation layer containing a charge transport material is used as the charge generation layer. A laminated function-separated type photosensitive layer is particularly preferred.

The charge generating layer can be formed by applying a coating solution obtained by dispersing the above disazo pigment together with a binder resin in a suitable solvent onto a conductive support by a known method. The thickness is, for example, 5 μm or less,
It is preferable to form a thin film layer having a thickness of 0.1 to 1 μm. The binder resin used at this time is selected from a wide range of insulating resin or organic photoconductive polymer,
Substituted or unsubstituted polyvinyl butyral, polyvinyl benzal, polyarylate, polycarbonate, polyester, phenoxy resin, cellulosic resin, acrylic resin, polyurethane, and the like are preferable, and the amount of use is 80% by weight in the charge generation layer. Below, preferably 40
% By weight or less. The solvent used is preferably selected from those which dissolve the resin and do not dissolve the charge transport layer and the undercoat layer described below. Specifically, ethers such as tetrahydrofuran and 1,4-dioxane, ketones such as cyclohexanone and methyl ethyl ketone, N, N
Amides such as dimethylformamide, methyl acetate,
Esters such as ethyl acetate, aromatics such as toluene, xylene and chlorobenzene, alcohols such as methanol, ethanol and 2-propanol, and aliphatic halogens such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride and trichloroethylene. Hydrocarbons and the like.

The charge transport layer is stacked on or below the charge generation layer, and has a function of receiving charge carriers from the charge generation layer in the presence of an electric field and transporting the carriers. The charge transporting layer is formed by dissolving a charge transporting material in a solvent together with a suitable binder resin as required and applying the solution. The film thickness is generally 5 to 40 μm, but 15 to 30 μm.
Is preferred.

The charge transporting substance includes an electron transporting substance and a hole transporting substance.
Examples thereof include electron-withdrawing substances such as 4,7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, chloranil, and tetracyanoquinodimethane, and those obtained by polymerizing these electron-withdrawing substances. Examples of the hole-transporting substance include polycyclic aromatic compounds such as pyrene and anthracene, carbazole compounds, indole compounds, imidazole compounds,
Oxazole, thiazole, oxadiazol,
Heterocyclic compounds such as pyrazole, pyrazoline, thiadiazol and triazole compounds, p-diethylaminobenzaldehyde-N, N-diphenylhydrazone, N, N-diphenylhydrazino-3-methylidene-
Hydrazone compounds such as 9-ethylcarbazole, α
Styryl compounds such as -phenyl-4'-N, N-diphenylaminostilbene, 5- [4- (di-p-tolylamino) benzylidene] -5H-dibenzo [a, d] cycloheptene, benzidine compounds and triaryl- Methane compounds, triarylamine compounds, triphenylamine, and polymers having a group consisting of these compounds in the main chain or side chain (for example, poly-N-vinylcarbazole, polyvinylanthracene, etc.). In addition to these organic charge transport materials, inorganic materials such as selenium, selenium-tellurium, amorphous silicon, and cadmium sulfide can be used. These charge transport materials can be used alone or in combination of two or more. When the charge transport material does not have a film-forming property, an appropriate binder can be used. In particular,
Insulating resin such as acrylic resin, polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile styrene copolymer, polyacrylamide, polyamide, chlorinated rubber or organic photoconductive polymer such as poly-N-vinylcarbazole, polyvinylanthracene, etc. .

As the conductive support on which the photosensitive layer is formed, for example, aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold and platinum are used. In addition, plastics (eg, polyethylene,
A support or conductive particles obtained by coating conductive particles (for example, carbon black, silver particles, etc.) and a suitable binder resin on a plastic or metal substrate or a conductive material such as polypropylene or polyvinyl chloride, polyethylene terephthalate, acrylic resin, etc. A support impregnated with the resin can be used.

An undercoat layer having a barrier function and an adhesive function can be provided between the conductive support and the photosensitive layer. The undercoat layer can be formed of casein, polyvinyl alcohol, nitrocellulose, polyamide (nylon 6, nylon 66, nylon 610, copolymer nylon, alkoxymethylated nylon, etc.), polyurethane, aluminum oxide, or the like. The thickness of the undercoat layer is 5 μm or less, preferably 0.1 to 3 μm.

Another specific example of the present invention is an electrophotographic photoreceptor in which the above-mentioned disazo pigment and a charge transport material are contained in the same layer. In this case, a charge transfer complex composed of poly-N-vinylcarbazole and trinitrofluorenone can be used as the charge transport material. The electrophotographic photoreceptor of this example can be formed by applying and drying a liquid in which the above-mentioned disazo pigment and the charge transfer complex are dispersed in an appropriate resin solution. The pigment used in any of the electrophotographic photoreceptors may be amorphous or crystalline in the form of the disazo pigment represented by the general formula (1). It is also possible to use a combination of two or more of the disazo pigments shown, or a combination with a known charge generating substance.

The electrophotographic photosensitive member of the present invention can be used not only for an electrophotographic copying machine but also for a laser beam printer,
RT printer, LED printer, LCD printer,
It can be widely used in electrophotographic applications such as laser plate making and facsimile.

Next, an electrophotographic apparatus provided with the electrophotographic photosensitive member of the present invention and a facsimile will be described.

FIG. 1 shows a schematic configuration of a general transfer type electrophotographic apparatus using the drum type photosensitive member of the present invention. In the figure, reference numeral 1 denotes a drum type photosensitive member as an image carrier, and a shaft 1
It is rotationally driven at a predetermined peripheral speed in the direction of the arrow around a.
The photoreceptor 1 is uniformly charged with a predetermined positive or negative potential on its peripheral surface by a charging means 2 during the rotation process, and then, in an exposure section 3, a light image exposure L (slit exposure / (Laser beam scanning exposure, etc.). As a result, an electrostatic latent image corresponding to the exposure image is sequentially formed on the peripheral surface of the photoconductor. The electrostatic latent image is then toner-developed by the developing means 4, and the toner-developed image is rotated by the transfer means 5 between the photosensitive member 1 and the transfer means 5 from a paper feeding unit (not shown). Are sequentially transferred onto the surface of the transfer material P fed in synchronization with the transfer. The transfer material P having undergone the image transfer is separated from the photoreceptor surface, introduced into the image fixing means 8 and subjected to image fixing to be printed out as a copy (copy) outside the machine. The surface of the photoreceptor 1 after the image transfer is cleaned and cleaned by removing the transfer residual toner by the cleaning means 6, and is subjected to static elimination by the pre-exposure means 7, and is repeatedly used for image formation. As the uniform charging means 2 for the photoreceptor 1, a corona charging device is generally widely used. Also, the corona transfer means is generally widely used for the transfer device 5. As an electrophotographic apparatus, a plurality of components such as the above-described photoreceptor, developing means, and cleaning means are integrally connected as an apparatus unit, and this unit is detachably attached to the apparatus body. You may comprise. For example, the photoreceptor 1 and the cleaning means 6 may be integrated into one apparatus unit, and may be configured to be detachable using guide means such as rails of the apparatus body. At this time, the above-described device unit may be provided with a charging unit and / or a developing unit. In the case where the electrophotographic apparatus is used as a copying machine or a printer, the light image exposure L is performed by reflecting or transmitting light from a document or by reading a document and converting it into a signal.
The scanning of the laser beam, the driving of the light emitting diode array, or the driving of the liquid crystal shutter array is performed by this signal.

When used as a facsimile printer, the light image exposure L is an exposure for printing received data.

FIG. 2 is a block diagram showing an example of this case. The controller 11 controls the image reading section 10 and the printer 19. The entire controller 11 is controlled by the CPU 17. The read data from the image reading unit is transmitted to the partner station through the transmission circuit 13. Data received from the partner station is sent to the printer 19 through the receiving circuit 12. Predetermined image data is stored in the image memory. A printer controller 18 controls a printer 19. 14 is a telephone. Line 15
(Received from a remote terminal connected via a line) are demodulated by the receiving circuit 12, and then the CPU 17 performs signal processing of the image information and is sequentially stored in the image memory 16. . When at least one page of the image is stored in the memory 16, the image of the page is stored. The CPU 17 reads out one page of image information from the memory 16 and sends out one page of image information signaled to the printer controller 18. Upon receiving one page of image information from the CPU 17, the printer controller 18 controls the printer 19 to record the image information of the page. Note that the CPU 17 is a printer 19
During the recording by, the next page is received. As described above, image reception and recording are performed.

[0037]

Examples 1 to 10 5 g of methoxymethylated nylon (weight average molecular weight 32,000) and 10 g of alcohol-soluble copolymerized nylon (weight average molecular weight 29,000) on an aluminum support were treated with methanol. 95
The solution dissolved in g was applied with a Myr bar to form an undercoat layer having a thickness of 1 μm after drying. Next, 5 g of Pigment 1 was added to a solution prepared by dissolving 2 g of butyral resin (butyralization degree: 63 mol%) in 95 g of cyclohexanone, and dispersed by a sand mill for 20 hours. This dispersion was applied on a previously formed undercoat layer with a Myr bar so as to have a thickness of 0.2 μm after drying, and dried to form a charge generation layer.

Next, a hydrazone compound represented by the following structural formula 5 g of polymethyl methacrylate (weight average molecular weight 10
5 g was dissolved in 40 g of chlorobenzene, and this was coated on the charge generation layer with a Myr bar so that the film thickness after drying was 19 μm, and dried to form a charge transport layer. Was prepared.

Electrophotographic photoreceptors corresponding to Examples 2 to 10 were prepared in exactly the same manner except that other exemplary pigments were used in place of Pigment 1.

The electrophotographic photosensitive member thus produced was used by Kawaguchi Electric Co., Ltd.
Made using a electrostatic tester Model SP-428, negatively charged by -5 KV corona discharge, held for 1 second in a dark place, and then exposed to illuminance of 10 lux using a halogen lamp to evaluate the charging characteristics. did. As the charging characteristics, the surface potential V ₀ and the exposure amount E1 / 6 required for the surface potential after being left in a dark place to attenuate to 1/6 were measured. The results are shown.

Example 1 Pigment 1 V ₀ : −700 V, E1 / 6: 1.2 lux · second Example 2 Pigment 3 V ₀ : −700 V, E1 / 6: 1.1 lux · second Example 3 Pigment 11 _{V 0: -700V, E1 / 6} : 1.1 lux · sec example 4 pigment _{15 V 0: -705V, E1 /} 6: 1.4 lux · sec example 5 pigment 22 V _0: -700V, E1 / 6: 1.0 lux · sec example 6 pigment _{25 V 0: -680V, E1 /} 6: 1.6 lux · sec example 7 pigment _{43 V 0: -695V, E1 /} 6: 1.3 lux · sec example 8 pigment _{49 V 0: -695V, E1 /} 6: 1.3 lux · sec example 9 pigment _{57 V 0: -700V, E1 /} 6: 1.2 lux · sec example 10 pigment 78 V _0: -710V, E1 / 6: 1.0 lux / sec

Comparative Examples 1 and 2 An electrophotographic photosensitive member was prepared in exactly the same manner as in Example 1 except that the disazo pigment used in Example 1 was replaced with Comparative Pigments 1 and 2 shown in Table 18, and charged similarly. The properties were evaluated. The results are shown. Table 18 Comparative Example 1 Comparative Pigment 1 V ₀ : -630 V, E1 / 6: Unmeasurable Comparative Example 2 Comparative Pigment 2 V ₀ : -680 V, E1 / 6: 4.7 lux · sec From these results, the electrophotography of the present invention It can be seen that the photoreceptor has sufficient chargeability and excellent sensitivity.

Examples 11 to 15 The electrophotographic photosensitive members prepared in Examples 1, 2, 4, 5 and 9 were treated with a corona charger of -6.5 KV, exposure light: chemical system, developing unit, transfer charger, It was affixed to a cylinder of an electrophotographic copying machine equipped with a charge removing exposure optical system and a cleaner. Initial dark potential V _D and the light portion potential V _L respectively -700 V, -
The fluctuation amount ΔV _D of the dark portion potential and the fluctuation amount ΔV _L of the light portion potential were measured when the voltage was set to around 200 V and used 5,000 times. The results are shown. Note that a negative sign in the fluctuation amount of the potential indicates a decrease in the absolute value of the potential, and a positive sign indicates an increase in the absolute value of the potential. Example _{11 ΔV D: -10V, ΔV L} : 0V Example _{12 ΔV D: 0V, ΔV L} : + 5V Example _{13 ΔV D: 0V, ΔV L} : + 5V Example _{14 ΔV D: -5V, ΔV L} : 0V Example 15 ΔV _D : -15 V, ΔV _L : +10 V

Comparative Examples 3 and 4 With respect to the electrophotographic photosensitive members prepared in Comparative Examples 1 and 2,
In the same manner as in Example 11, the potential fluctuation during repeated use was measured. The results are shown. Example 3 ΔV _D : −55 V, ΔV _L : +20 V Example 4 ΔV _D : −40 V, ΔV _L : +30 V From the above results, it can be seen that the electrophotographic photoreceptor of the present invention has little potential fluctuation when repeatedly used. .

Example 16 An undercoat layer of polyvinyl alcohol having a thickness of 0.5 μm was formed on an aluminum surface of an aluminum-deposited polyethylene terephthalate film. The dispersion of the disazo pigment used in Example 3 was applied thereon with a Myer bar and dried to form a film having a thickness of 0.2.
A μm charge generation layer was formed. Then, 5 g of a styryl compound having the following structural formula and A solution prepared by dissolving 5 g of polycarbonate (weight average molecular weight: 55,000) in 40 g of tetrahydrofuran was applied on the charge generation layer and dried to form a charge transport layer having a thickness of 19 μm. The charging characteristics and durability characteristics of the produced electrophotographic photosensitive member were measured by the same methods as in Examples 1 and 11. The results are shown. _{V 0: -700V, E1 / 6} : 1.1
Looks / second, ΔV _D : -5V, ΔV _L : 0V

Example 17 An undercoat layer of polyvinyl alcohol having a thickness of 0.5 μm was formed on the aluminum surface of an aluminum-deposited polyethylene terephthalate film. The dispersion of the disazo pigment used in Example 4 was applied thereon with a Myer bar and dried to form a film having a thickness of 0.2.
A μm charge generation layer was formed. Next, 5 g of a fluorene compound having the following structural formula A solution prepared by dissolving 5 g of polycarbonate (weight average molecular weight: 55,000) in 40 g of tetrahydrofuran was applied on the charge generation layer and dried to form a charge transport layer having a thickness of 21 μm. The charging characteristics and the durability characteristics of the produced electrophotographic photosensitive member were measured by the same methods as in Example 1. The results are shown. _{V 0: -700V, E1 / 6} : 1.1 Looks
Seconds, ΔV _D : 0V, ΔV _L : 0V

Example 18 An electrophotographic photosensitive member was prepared by applying the charge generation layer and the charge transport layer of the electrophotographic photosensitive member prepared in Example 5 in reverse order, and the charging characteristics were evaluated in the same manner as in Example 1. . However, the charging was positive. V ₀ : +705 V, E1 / 6: 0.9
Looks Second

Example 19 5 g of 2,4,7-trinitro-9-fluorenone and poly-4,4'-dioxydiphenyl-2,2-propane carbonate were placed on the charge generation layer prepared in Example 5. A solution prepared by dissolving 5 g of (molecular weight 300,000) in 50 g of tetrahydrofuran was applied with a Myer bar, and a charge transport layer having a thickness of 19 μm after drying was formed. The charging characteristics of the produced electrophotographic photosensitive member were evaluated in the same manner as in Example 1. However, the charging was positive. V ₀ : + 685V, E1 / 6: 1.
2 looks second.

Example 20 0.5 g of pigment 7 was dispersed in a paint shaker together with 9.5 g of cyclohexanone for 5 hours. Here, 5 g of the same charge transporting material and 5 g of polycarbonate as used in Example 1 were used.
Was dissolved in 40 g of tetrahydrofuran, and the mixture was further stirred for 1 hour. The coating solution thus prepared was coated on an aluminum support with a Myer bar and dried to a film thickness of 18 μm.
m of the photosensitive layer was formed. The electrophotographic photosensitive member thus produced was evaluated for charging characteristics in the same manner as in Example 1. The charging was positive. V ₀ : +690 V, E1 / 6: 1.0
Looks second.

[0050]

According to the electrophotographic photoreceptor of the present invention, by using a compound having a specific structure in the photosensitive layer, the electrophotographic characteristics of the electrophotographic photoreceptor can be improved in terms of high sensitivity, repeated charging and continuous image formation by exposure. This is effective in exhibiting a remarkable effect that the fluctuation in the light portion potential and the dark portion potential is small and the durability is excellent. The same effect can be obtained in an electrophotographic apparatus and a facsimile provided with the electrophotographic photosensitive member.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a general transfer type electrophotographic apparatus.

FIG. 2 is a block diagram of a facsimile using the electrophotographic apparatus as a printer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Drum type photoreceptor as an image carrier (electrophotographic photoreceptor of the present invention) 1a shaft 2 Corona charging device 3 Exposure unit 4 Developing unit 5 Transfer unit 6 Cleaning unit 7 Pre-exposure unit 8 Image fixing unit L Optical image Exposure P Transfer material after image transfer 10 Image reading unit 11 Controller 12 Receiving circuit 13 Transmitting circuit 14 Telephone 15 Line 16 Image memory 17 CPU 18 Printer controller 19 Printer

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-61-259257 (JP, A) JP-A-1-185636 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 5/00-5/16

Claims (4)

(57) [Claims] 1. An electrophotographic photoreceptor comprising a photosensitive layer containing a disazo pigment represented by the following general formula (1) on a conductive support. General formula (1) (In the formula, A ₁ and A ₂ are the same or different and represent a coupler residue having a phenolic hydroxyl group.) 2. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer comprises at least two layers of a charge generation layer containing a disazo pigment represented by the general formula (1) and a charge transport layer. 3. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1. 4. A facsimile having an electrophotographic apparatus provided with the electrophotographic photosensitive member according to claim 1, and a means for receiving image information from a remote terminal.