JP2945782B2 - 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.

Azo pigments have excellent photoconductivity, and compounds having various characteristics can be relatively easily obtained by combining the azo component and the coupler component. Proposed. However, conventional electrophotographic photoreceptors using disazo pigments are not always sufficient in terms of sensitivity and potential stability when repeatedly used, and only practical materials are practically used. .

[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 excellent 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.

The general formula (1)

Embedded image In the formula, R ₁ and R ₂ are the same or different and represent a hydrogen atom, an alkyl group, an aralkyl group or an aryl group which may have a substituent, X represents an oxygen atom or a sulfur atom, and A ₁ and A ₂ is the same or different and represents a coupler residue represented by the general formula (2).

General formula (2)

Embedded image In the formula, Y represents a residue necessary for forming a polycyclic aromatic ring or a heterocyclic ring by condensing with a benzene ring, Z represents an oxygen atom or a sulfur atom, and R ₃ and R ₄ are the same or different. A hydrogen atom, an alkyl group which may have a substituent, an aralkyl group, an aryl group or a heterocyclic group;
₃ and R ₄ may combine with each other to form a ring together with the nitrogen atom.

Specifically, R ₁ and R ₂ in the general formula (1)
Is a hydrogen atom, an alkyl group such as methyl, ethyl and propyl, an aralkyl group such as benzyl and phenethyl, an aryl group such as phenyl and naphthyl, and examples of the substituent include a fluorine atom, a chlorine atom and a bromine atom. And alkyl groups such as methyl, ethyl and propyl, and alkoxy groups such as methoxy and ethoxy.

In the general formula (2), Y is a naphthalene ring,
Residues necessary for forming a ring such as an anthracene ring, a carbazole ring, a benzocarbazole ring, a dibenzofuran ring and the like are mentioned, and R ₃ and R ₄ are an alkyl group such as methyl, ethyl and propyl, benzyl and phenethyl Aralkyl groups such as phenyl, naphthyl, and anthryl
A heterocyclic group such as pyridyl, pyridyl, thienyl, carbazolyl, benzimidazolyl, or benzothiazolyl;
, Pyrroline, pyrrolidine, pyrrolidone, indole,
Indoline, carbazole, imidazole, pyrazo-
, Pyrazoline, oxazine, phenoxazine, etc. include a cyclic amino group containing a nitrogen atom in the ring, and examples of the substituent include a fluorine atom, a halogen atom such as a chlorine atom and a bromine atom, methyl, ethyl, and propyl. Alkyl groups such as methoxy and ethoxy; alkylamino groups such as dimethylamino and diethylamino; and halomethyl groups such as phenylcarbamoyl group, nitro group, cyano group and trifluoromethyl group.

In the case where Y in the general formula (2) is a coupler residue forming a benzocarbazole ring, the pigment has a semiconductor laser which has an absorption range extending to near infrared region. It is also suitable as a charge generation material for the laser.

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 photosensitive member 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 listed in Tables 1 to 7, 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.

[0015]

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

[Table 7]

The disazo pigment represented by the general formula (1) is obtained by subjecting a corresponding diamine to tetrazotization by an ordinary method and coupling with a coupler in an aqueous system in the presence of an alkali, or converting a tetrazonium salt into a borofluoride salt or a 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 A1 and A2 in formula (1) are different couplers are synthesized, first, one mole of one coupler is coupled to 1 mole of the above-described tetrazonium salt, and then the other is mixed. Either the coupler 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 one coupler. And then diazotized again to couple the other coupler.

Synthesis Example (Synthesis of Illustrative Pigment (1)) 150 ml of water was added to a 300 ml beaker.
20 ml of concentrated hydrochloric acid (0.23 mol)

Embedded image Was cooled to 0 ° C., and 4.6 g (0.067 mol) of sodium nitrite was added to 10 parts of water.
While maintaining the liquid temperature at 5 ° C, dissolve the liquid dissolved in
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 12.4 g, 75%.

Next, 500 ml of DMF was placed in a 1 liter beaker, and the following compound

Embedded image After dissolving 12.9 g (0.042 mol) and cooling the solution to 5 ° C., 10.3 g (0.02 mol) of the previously obtained borofluoride salt was dissolved.
0 mol) and then 5.1 g of triethylamine.
(0.050 mol) 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 15.2 g, 80%.

The electrophotographic photoreceptor 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 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,
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.

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, 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 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 photosensitive member 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. In any of the electrophotographic photoreceptors, the crystal form of the disazo pigment represented by the general formula (1) may be amorphous or crystalline, and if necessary, the disazo pigment represented by the general formula (1) may be used. It is also possible to use a combination of two or more pigments 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 and a facsimile provided with the electrophotographic photosensitive member of the present invention will be described. FIG.
FIG. 1 shows a schematic configuration of a general transfer type electrophotographic apparatus using the drum type photoreceptor of the present invention. In FIG. 1, reference numeral 1 denotes a drum-type photosensitive member as an image carrier, which is driven to rotate around an axis 1a in a direction of an arrow at a predetermined peripheral speed. 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). 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 transferred by a cleaning means 6 to a transfer residual toner
Is removed, the surface is cleaned, the pre-exposure means 7 removes electricity, and is repeatedly used for image formation. Photoconductor 1
As the uniform charging means 2, 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. Further, the light image exposure L is performed by using an electrophotographic apparatus as a copying machine or a printer.
In the case of using as a light source, reflected light or transmitted light from a document is used, or a document is read and converted into a signal, and scanning of a laser beam, driving of a light emitting diode array, or liquid crystal shutter is performed according to the signal. This is performed by driving an array or the like. Also, a facsimile printer
In the case of using the light image exposure, the light image exposure L is an exposure for printing the 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.

[0029]

【Example】

Examples 1 to 25 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) were placed on an aluminum support in 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 cyclohexanone 90
g of butyral resin (butyralization degree: 63 mol%)
g was dissolved in the solution, and dispersed in a sand mill for 20 hours. This dispersion was applied on a previously formed undercoat layer with a Myr bar so that the thickness after drying was 0.3 μm, and dried to form a charge generation layer.

Next, a hydrazone compound represented by the following structural formula

Embedded image 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 generating layer with a Myer bar so that the film thickness after drying was 20 μm, and dried to form a charge transport layer. Was prepared.

Electrophotographic photosensitive members corresponding to Examples 2 to 22 were prepared in exactly the same manner, except that other exemplified pigments were used in place of Pigment 1.

The produced electrophotographic photosensitive member was used by Kawaguchi Electric Co., Ltd.
Was negatively charged by a corona discharge of -5 KV using an electrostatic copying paper tester Model SP-428, and was held for 1 second in a dark place, and then exposed at an illuminance of 10 lux using a halogen lamp to evaluate charging characteristics. . 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 : -700 V, E1 / 2: 1.2 lux · second Example 2 Pigment 2 V ₀ : -700 V, E1 / 2: 0.8 lux · second Example 3 Pigment 3 _{V 0: -705V, E1 / 2} : 1.5 lux · sec example 4 pigment _{4 V 0: -700V, E1 /} 2: 1.2 lux · sec example 5 pigment 5 V _0: -695V, E1 / 2: 1.0 lux · sec example 6 pigment _{6 V 0: -700V, E1 /} 2: 0.9 lux · sec example 7 pigment _{7 V 0: -720V, E1 /} 2: 1.8 lux · sec example 8 pigment _{8 V 0: -700V, E1 /} 2: 1.3 lux · sec example 9 pigment _{9 V 0: -700V, E1 /} 2: 1.7 lux · sec example 10 pigment 10 V _0: -700V, E1 / 2: 1.1 lux · sec example 11 pigment 11 V _0: -6 0V, E1 / 2: 0.8 lux · sec Example 12 Pigment _{12 V 0: -700V, E1 /} 2: 0.8 lux · sec Example 13 Pigment _{13 V 0: -700V, E1 /} 2: 1. 5 lux / sec Example 14 Pigment 14 V ₀ : -710 V, E1 / 2: 2.0 lux / sec Example 15 Pigment 15 V ₀ : -705 V, E1 / 2: 1.5 lux / sec Example 16 Pigment _{16 V 0: -700V, E1 /} 2: 1.0 lux · sec example 17 pigment _{17 V 0: -700V, E1 /} 2: 1.6 lux · sec example 18 pigment 18 V _0: -680V, E1 /2:1.0 lux · sec example 19 pigment _{19 V 0: -690V, E1 /} 2: 1.8 lux · sec example 20 pigment _{20 V 0: -675V, E1 /} 2: 1.1 lux · Second Example 21 Pigment 21 V ₀ : −665 V, E1 / 2: 1.2 lux-seconds Example 22 pigment _{22 V 0: -700V, E1 /} 2: 0.9 lux-seconds Example 23 pigment _{23 V 0: -680V, E1 /} 2: 1.4 lux · second example 24 pigment _{24 V 0: -690V, E1 /} 2: 1.0 lux · sec example 25 pigment _{25 V 0: -695V, E1 /} 2: 1.5 lux · sec

Comparative Examples 1 and 2 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the disazo pigment used in Example 1 was replaced with Comparative Pigment 1 and Comparative Pigment 2 shown in Table 8 below. Similarly, the charging characteristics were evaluated. The results are shown.

Comparative Example 1 Comparative Pigment 1 V ₀ : -700 V, E1 / 2: 2.2 lux · sec Comparative Example 2 Comparative Pigment 2 V ₀ : -690 V, E1 / 2: 2.6 lux · sec From these results It can be seen that the electrophotographic photoreceptor of the present invention has sufficient charging ability and excellent sensitivity.

[0037]

[Table 8]

Examples 26 to 38 The electrophotographic photosensitive member prepared in Example 1 was equipped with a corona charger of -6.5 KV, an exposure optical system, a developing device, a transfer charger, a charge removing exposure optical system, and a cleaner. To a cylinder of an electrophotographic copying machine. Initial dark potential V _D and the light portion potential V _L respectively set -700 V, in the vicinity of -200 V,
The amount of change in the dark area potential (Δ
V _D ) and the variation (ΔV _L ) of the light portion potential were measured. The electrophotographic photoreceptors prepared in Examples 2 to 25 were similarly evaluated. 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 26 ΔV _D : +10 V, ΔV _L :
+15 V Example 27 ΔV _D : 0 V, ΔV _L : +10 V Example 28 ΔV _D : −20 V, ΔV _L : +10 V Example 29 ΔV _D : −5 V, ΔV _L : 0 V Example 30 ΔV _D : 0 V, ΔV _L : + 5V Example 31 ΔV _D : 0 V, ΔV _L : +5 V Example 32 ΔV _D : −10 V, ΔV _L : 0 V Example 33 ΔV _D : 0 V, ΔV _L : +5 V Example 34 ΔV _D : 0 V, ΔV _L : +10 V Example 35 ΔV _D : +5 V, ΔV _L : +5 V Example 36 ΔV _D : −10 V, ΔV _L : +10 V Example 37 ΔV _D : −10 V, ΔV _L : +10 V Example 38 ΔV _D : −15 V, ΔV _L : -10V

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 26, the potential fluctuation during repeated use was measured. The results are shown. Comparative Example 3 ΔV _D : −30 V, ΔV _L : +60 V Comparative Example 4 ΔV _D : −65 V, ΔV _L : +80 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 39 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 2 was applied thereon with a Myr 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

Embedded image 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 22 μm. With respect to the produced electrophotographic photosensitive member, the charging characteristics and the durability characteristics were measured by the same methods as in Examples 1 and 26. The results are shown. V ₀ : -715 V, E1 / 2: 0.7 lux · sec ΔV _D : −5 V, ΔV _L : +5 V

Example 40 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 39 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: 1.0 lux · sec.

Example 41 5 g of 2,4,7-trinitro-9-fluorenone and poly-4,4'-dioxydiphenyl-2,2-propane carbonate were deposited on the charge generation layer prepared in Example 2. 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 18 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 : +680 V, E1 / 2: 3.
80 looks second

Example 42 0.5 g of Pigment 2 was dispersed together with 9.5 g of cyclohexanone in a paint shaker for 5 hours. Example 39 here
5 g of the same charge transporting material as used in
g was dissolved in 40 g of tetrahydrofuran, and the mixture was further stirred for 1 hour. The coating solution thus prepared was applied to an aluminum support with a Myer bar and dried to obtain a film thickness of 20.
A photosensitive layer having a thickness of μm 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 / 2: 5.5 lux / sec

[0046]

According to the electrophotographic photoreceptor of the present invention, by using a disazo pigment having a specific structure in the photosensitive layer, either one or both of the efficiency of charge carrier generation and the efficiency of injection in the photosensitive layer are improved. It has a remarkable effect that characteristics excellent in sensitivity and potential stability upon repeated use can be obtained, and the same remarkable effect can be obtained in an electrophotographic apparatus and a facsimile equipped 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

Claims (4)

(57) [Claims] 1. An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer contains a disazo pigment represented by the general formula (1). General formula (1) In the formula, R ₁ and R ₂ are the same or different and represent a hydrogen atom, an alkyl group, an aralkyl group or an aryl group;
Represents an oxygen atom or a sulfur atom, and A ₁ and A ₂ are the same or different and represent a coupler residue represented by the general formula (2). General formula (2) In the formula, Y represents a residue necessary for forming a polycyclic aromatic ring or a heterocyclic ring by condensing with a benzene ring, Z represents an oxygen atom or a sulfur atom, and R ₃ and R ₄ are the same or different. A hydrogen atom, an alkyl group which may have a substituent, an aralkyl group, an aryl group or a heterocyclic group;
₃ and R ₄ may combine with each other to form a ring together with the nitrogen atom. 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.