JP2963212B2 - 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. And, for example,
JP-A-131515, JP-A-57-47357, JP-A-54-22834, and the like. 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 good high sensitivity characteristics and stable potential characteristics when used repeatedly. An 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)

The general formula (1) In the formula, Y ₁ represents an optionally substituted methylene group, ethylene group, propylene group or o-phenylene group,
R ₁ and R ₂ are the same or different and represent a hydrogen atom, a halogen atom, a trifluoromethyl group or an alkyl group which may have a substituent, and A ₁ and A ₂ are the same or different and represent a phenolic hydroxyl group. The following shows coupler residues. Specifically, alkyl, methyl, ethyl,
Groups such as propyl and butyl. Methylene group,
Examples of the substituent in the ethylene group, the propylene group, the o-phenylene group and the alkyl group include a halogen atom, a nitro group, a cyano group and a halomethyl group.

Preferred examples of the coupler residue having a phenolic hydroxyl group represented by A ₁ and A ₂ include residues represented by the following general formulas (2) to (7).

General formula (2)

General formula (3)

General formula (4)

General formula (5)

General formula (6)

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 by condensing with a benzene ring;
A residue necessary for forming a polycyclic aromatic ring or a heterocyclic ring such as a benzocarbazole ring or a dibenzofuran ring; and Y ₂ in the general formula (7) represents a divalent aromatic hydrocarbon which may have a substituent. A hydrogen group or a divalent heterocyclic group containing a nitrogen atom in the ring, specifically, o-phenylene, o-naphthylene, perinaphthylene, 1,2-anthrylene, 3,4-
Pyrazoldiyl, 2,3-pyridinediyl, 4,5-
Pyridinediyl, 6,7-indazolediyl, 6,7
And R ₃ and R ₄ in the general formulas (2) and (3) are a hydrogen atom, an alkyl group which may have a substituent, an aryl group, and an aralkyl group. Or a heterocyclic group; R ₃ and R ₄ may be bonded via a nitrogen atom to form a cyclic amino group; R ₅ in the general formulas (4) and (5) represents a hydrogen atom; Represents an alkyl group, an aryl group, an aralkyl group or a heterocyclic group which may have a group, and R ₆ 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, wherein the alkyl group in the above expression is a group such as methyl, ethyl or propyl; and specific examples of the aryl group are phenyl and Groups such as naphthyl and anthryl; aralkyl groups such as benzyl and phenethyl; heterocyclic groups such as pyridyl, thienyl, carbazolyl, benzimidazolyl and benzothiazolyl;
, Pyrroline, pyrrolidine, pyrrolidone, indole,
Indoline, carbazole, imidazole, pyrazo-
, 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, Examples thereof include a nitro group, a cyano group, and a halomethyl group such as trifluoromethyl. Z in the general formulas (2) and (4) represents an oxygen atom or a sulfur atom, and n 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 Tables 1-1 to 1-15. The disazo pigment represented by the general formula (1) used in the present invention is It is not limited to these. In the table, the specific structure of the pigment is represented by describing only the portions that change in the following basic types.

Basic type A ₁ -N = N−M−N = N−
A ₂

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

The disazo pigment represented by the general formula (1) can be prepared by subjecting a corresponding diamine to tetrazotization by a conventional method and coupling with a coupler in an aqueous system in the presence of an alkali, 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 mole of one of the couplers is firstly coupled to 1 mol of the above-mentioned tetrazonium salt, and then the other. One of the couplers is synthesized by coupling 1 mol, or one amino group of the diamine is protected with an acetyl group or the like, and this is diazotized to couple the other coupler. It can be synthesized by hydrolyzing with hydrochloric acid or the like, diazotizing it again and coupling the other coupler.

Synthesis Example (Synthesis of Pigment 1) 150 ml of water was added to a 300 ml beaker.
20 ml of concentrated hydrochloric acid (0.23 mol) Was cooled to 0 ° C., and 4.6 g (0.067 mol) of soda nitrite was added to 10 parts of water.
The liquid dissolved in milliliter was added dropwise over 10 minutes while keeping the liquid temperature at 2 ° C or lower. After stirring for 15 minutes, the mixture was filtered through carbon, and 10.5 g of sodium borofluoride (0.
(096 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 17.6 g, 82%.

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 temperature of the solution was cooled to 5 ° C. Then, 13.4 g (0.020 mol) of the borofluoride salt obtained above was dissolved, and then 5.1 g (0.050 mol) of N-methylmorpholine.
Mol) was added dropwise over 1 minute. 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 19.4 g, 95% yield

Elemental analysis value C calculated value 77.63%, measured value 77.13% H calculated value 4.74%, measured value 4.79% N calculated value 8.23%, measured value 8.52%

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 generation layer can be formed by applying a coating solution obtained by dispersing the above disazo pigment together with a binder resin in an appropriate 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,
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 or less, preferably 40% by weight, in the charge generation layer. % 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, amides such as N, N-dimethylformamide, esters such as methyl acetate and ethyl acetate, toluene, Examples include aromatics such as xylene and chlorobenzene, alcohols such as methanol, ethanol, and 2-propanol; and aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichloroethylene.

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.

As the charge transporting substance, there are 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, triphenylamines or polymers having a group consisting of these compounds in the main or side chain
(For example, poly-N-vinyl carbazole, polyvinyl anthracene, 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. Specifically, acrylic resin, polyarylate, polyester, polycarbonate, polystyrene,
Examples thereof include insulating resins such as acrylonitrile styrene copolymer, polyacrylamide, polyamide, and chlorinated rubber, and organic photoconductive polymers such as poly-N-vinylcarbazole and polyvinylanthracene.

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 may 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 is suitable.

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 receives a uniform charge of 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 / light exposure) by an image exposure means (not shown). (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 an original or by reading an original 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 10 controls the image reading unit 9 and the printer 18 . The entire controller 10 is C
It is controlled by the PU 16 . The read data from the image reading unit is transmitted to the partner station through the transmission circuit 12 . Data received from the partner station is sent to the printer 18 through the receiving circuit 11 . Predetermined image data is stored in the image memory. The printer controller 17 controls the printer 18 . 13 is a telephone. Line 14
(Received from a remote terminal connected via a line) are demodulated by the receiving circuit 11 , and then the CPU 16 performs signal processing of the image information and sequentially stores the processed signal in the image memory 15. You. When at least one page of the image is stored in the memory 15 , the image of the page is stored. The CPU 16 reads out one page of image information from the memory 15 and sends out one page of image information converted into a signal to the printer controller 17 . Upon receiving one page of image information from the CPU 16 , the printer controller 17 controls the printer 18 to record the image information of the page. Note that the CPU 16 is connected to a printer.
During recording by 18 , the next page is being received.
As described above, image reception and recording are performed.

[0037]

Examples 1 to 15 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 Myer bar so that the film thickness after drying was 0.3 μm, and dried to form a charge generation layer.

Next, 5 g of a hydrazone compound represented by the following structural formula was Polymethyl methacrylate (weight average molecular weight 100,000) 5
g was dissolved in 40 g of chlorobenzene, and this was coated on the charge generation layer with a Myer bar so that the film thickness after drying was 19 μm, and dried to form a charge transport layer. A photoreceptor was prepared.

Example 2 was replaced by another pigment instead of pigment 1.
Electrophotographic photosensitive members corresponding to Nos. To 15 were prepared in exactly the same manner.

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 / 2) required for the surface potential after leaving in a dark place to attenuate to １ ／ were measured. The results are shown.

Example 1 Pigment 1 V ₀ = −710 V, E1 / 2 = 1.82 lux · second Example 2 Pigment 2 V ₀ = −705 V, E1 / 2 = 1.55 lux · second Example 3 Pigment 4 V ₀ = −700 V, E1 / 2 = 1.20 lux · sec. Example 4 Pigment 5 V ₀ = −700 V, E1 / 2 = 1.42 lux · sec. Example 5 Pigment 10 V ₀ = −700 V, E1 / 2 = 1.10 lux · sec. Example 6 Pigment 16 V ₀ = −700 V, E1 / 2 = 1.05 lux · sec. Example 7 Pigment 17 V ₀ = −695 V, E1 / 2 = 1.82 lux · sec. Example 8 Pigment 18 V ₀ = −695 V, E1 / 2 = 2.10 lux · second Example 9 Pigment 27 V ₀ = −690 V, E1 / 2 = 1.30 lux · second Example 10 Pigment 30 V ₀ = -700V, E1 / 2 = 1.39 lux / sec Example 11 Pigment 34 V ₀ = −700 V, E1 / 2 = 2.45 lux · sec Example 12 Pigment 39 V ₀ = −700 V, E1 / 2 = 1.52 lux · sec Example 13 Pigment 40 V ₀ = -700V, E1 / 2 = 1.83 lux · sec example 14 pigment _{42 V 0 = -700V, E1 /} 2 = 1.30 lux · sec example 15 pigment _{45 V 0 = -700V, E1 /} 2 = 1 .25 looks second

Comparative Examples 1 and 2 An electrophotographic photosensitive member was prepared in exactly the same manner as in Example 1 except that the azo pigments used in Example 1 were replaced with Comparative Pigments 1 and 2 shown in Table 2. The charging characteristics were evaluated. The results are shown.

Table 2

Comparative Example 1 V ₀ = −650 V, E1 / 2 = 3.5 lux · sec Comparative Example 2 V ₀ = −700 V, E1 / 2 = 5.3 lux · sec From these results, the electrophotography of the present invention was obtained. It can be seen that the photoreceptor has sufficient chargeability and excellent sensitivity.

Examples 16 to 19 The electrophotographic photosensitive members prepared in Examples 1, 5, 9 and 10 were replaced with a corona charger of -6.5 KV, an exposure optical system, a developing device,
It was affixed to a cylinder of an electrophotographic copying machine equipped with a transfer charger, a neutralizing exposure optical system and a cleaner. Initial dark potential V _D and the light portion potential V _L respectively -700 V, -200
The voltage was set near V, and the amount of change in the dark area potential (ΔV _D ) and the amount of change in the light area potential (ΔV _L ) were measured when the device was repeatedly 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 16 ΔV _D = + 5 V, ΔV _L = 0 V Example 17 ΔV _D = −5 V, ΔV _L = 0 V Example 18 ΔV _D = 0 V, ΔV _L = + 5 V Example 19 ΔV _D = −5 V, ΔV _L = 0V

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 16, potential fluctuations during repeated use were measured. The results are shown. Comparative Example 3 ΔV _D = −80 V, ΔV _L = + 35 V Comparative Example 4 ΔV _D = −30 V, ΔV _L = + 20 V From the above results, it can be seen that the electrophotographic photoreceptor of the present invention has a small potential fluctuation upon repeated use. .

Example 20 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 liquid of the disazo pigment used in Example 9 was applied thereon with a Myer bar and dried to form a film having a thickness of 0.3.
A μm charge generation layer was formed. Then, 5 g of a styryl 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 generating layer and dried to form a charge transporting layer having a thickness of 20 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 _D = −700 V, E1 / 2 = 1.01 lux
Second, ΔV _D = 0V, ΔV _L = 0V

Example 21 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 20 in reverse order, and the charging characteristics were evaluated in the same manner as in Example 1. . However, the charging was positive. V ₀ = + 700 V, E1 / 2 = 2.08 lux · sec

Example 22 On the charge generating layer prepared in Example 1, 5 g of 2,4,7-trinitro-9-fluorenone and 5 g of poly-4,4'-dioxydiphenyl-2,2-propane carbonate were added. A solution prepared by dissolving 5 g of (molecular weight 300,000) in 50 g of tetrahydrofuran was applied with a Myer bar to form a charge transport layer having a thickness of 20 μm after drying. 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 = + 650 V, E1 / 2 =
4.50 lux seconds

Example 23 0.5 g of Pigment 1 was dispersed together with 9.5 g of cyclohexanone in a paint shaker 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 = + 700 V, E1 / 2 = 5.0 lux / sec

[0052]

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 9 Image reading unit 10 Controller 11 Receiving circuit 12 Transmission circuit 13 Telephone 14 Line 15 Image memory 16 CPU 17 Printer controller 18 Printer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 5/06

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, Y ₁ represents an optionally substituted methylene group, ethylene group, propylene group or o-phenylene group;
₁ and R ₂ are the same or different and represent a hydrogen atom, a halogen atom, a trifluoromethyl group or an alkyl group which may have a substituent, and A ₁ and A ₂ are the same or different and have a phenolic hydroxyl group Shows coupler residues. 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.