JP2968865B2 - 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. Has been proposed,
JP-A-180553 and JP-A-1-319754 are known. 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) and / or (2) on a conductive support. Consists of

The general formula (1)

Embedded image

General formula (2)

Embedded image In the formula, A ₁ and A ₂ are the same or different and are represented by the general formula (3)
Represents a coupler residue.

General formula (3)

Embedded image In the formula, X represents a residue necessary for condensing with a benzene ring to form a polycyclic aromatic ring or a heterocyclic ring, Z represents an oxygen atom or a sulfur atom, and R ₁ and R ₂ 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;
R ₁ and R ₂ may combine with each other to form a ring together with the nitrogen atom.

[0009] Specifically X is a naphthalene ring in the general formula (3) in, anthracene ring, carbazole - Le ring, Benzukarubazo - Le ring, include residues necessary for formation of a ring such as a dibenzofuran ring, R ₁ And R ₂ are an alkyl group such as methyl, ethyl and propyl; an aralkyl group such as benzyl and phenethyl; an aryl group such as phenyl, naphthyl and anthryl; a heterocyclic group such as pyridyl, thienyl, carbazolyl, benzimidazolyl and benzothiazolyl; -Pyrroline, pyrrolidine, pyrrolidone,
Indole, indoline, carbazole, imidazo-
, Pyrazolyl, pyrazoline, oxazine, cyclic amino group containing a nitrogen atom in the ring such as phenoxazine, and the like.Examples of the substituent include a fluorine atom, a chlorine atom,
Halogen atoms such as bromine atoms, alkyl groups such as methyl, ethyl and propyl; alkoxy groups such as methoxy and ethoxy; alkylamino groups such as dimethylamino and diethylamino; phenylcarbamoyl groups, nitro groups and halomethyl groups such as cyano and trifluoromethyl groups And the like.

Further, in the present invention, the photosensitive layer comprises at least two layers of a charge generating layer containing a disazo pigment represented by the general formula (1) and / or (2) and a charge transporting layer. Consists of the body. In the case where X in the general formula (3) is a coupler residue forming a benzocarbazole ring, the pigment has an absorption range extending to the vicinity of the near infrared region. As a charge generation material.

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 having 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) and / or (2) of the present invention are shown in Tables 1 to 1.
6, the disazo pigment used in the present invention is not limited to these. Illustrative pigments represent a specific structure by describing only the portions that change in the basic type.

[0014]

[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]

The disazo pigments represented by the general formulas (1) and (2) are prepared by subjecting the corresponding diamine to tetrazotization by a conventional method.
After coupling with a coupler in an aqueous system in the presence of an alkali, or after converting a tetrazonium salt to a borofluoride salt or a zinc chloride double salt, sodium acetate is dissolved in an organic solvent such as N, N-dimethylformamide or dimethylsulfoxide. It can be easily synthesized by coupling with a coupler in the presence of a base such as da, triethylamine and N-methylmorpholine.

When disazo pigments in which A ₁ and A _{2 in the} general formulas (1) and (2) are different couplers are synthesized, one mole of one of the couplers is first added to 1 mole of the above-mentioned tetrazonium salt. And then coupling the other coupler-1 mol to synthesize, or one amino group of the diamine is protected with an acetyl group or the like, and this is diazotized to couple one coupler. After the reaction, the protecting group is hydrolyzed with hydrochloric acid or the like, and this is diazotized again to be synthesized by coupling 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 16.0 g, 81.3%. Next, 500 ml of DMF is placed in a 1 liter beaker.

Embedded image Was dissolved in 12.9 g (0.042 mol), and the solution was cooled to 5 ° C., and then 12.3 g (0.04 mol) of the previously obtained borofluoride salt was dissolved.
20 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 17.9 g, 85.0 yield
%.

The electrophotographic photosensitive member of the present invention has a photosensitive layer containing a disazo pigment represented by the general formula (1) and / or (2) 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) and / or (2) is used as a charge generating layer, and a charge transport material is added thereto. A function-separated type photosensitive layer in which a charge transport layer is contained 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 photoreceptor in which the above-mentioned disazo pigment and a charge transporting substance 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 formulas (1) and (2) may be either amorphous or crystalline. ) And (2) may be used in combination of two or more, or in 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. 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. When the electrophotographic apparatus is used as a copying machine or a printer, the light image exposure L uses reflected light or transmitted light from a document, or reads a document and converts it into a signal. It is performed by scanning a beam, driving a light emitting diode array, or driving a liquid crystal shutter array. When used as a facsimile printer, 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.

[0027]

【Example】

Examples 1 to 22 5 g of methoxymethylated nylon (weight average molecular weight 32,000) and 10 g of alcohol-soluble copolymerized nylon (weight average molecular weight 33,000) on an aluminum support were treated with methanol 90.
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, 4.5 g of Pigment 1 was added to 85 g of cyclohexanone in butyral resin (butyralization degree: 72 mol%).
2 g was added to the dissolved solution, and the mixture was dispersed with a sand mill for 18 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, 5 g of a hydrazone compound represented by the following structural formula

Embedded image 5 g of polymethyl methacrylate (weight average molecular weight 90,000)
Is dissolved in 40 g of chlorobenzene, and this is coated on the charge generating layer so that the film thickness after drying is 22 μm.
And dried to form a charge transport layer, whereby an electrophotographic photoreceptor of Example 1 was prepared.

Example 2 was replaced by another pigment instead of pigment 1.
Electrophotographic photosensitive members corresponding to Nos. To 22 were prepared in exactly the same manner.

The prepared 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 being left in a dark place to attenuate to １ ／ were measured. The results are shown.

Example 1 Pigment 1 V ₀ : −710 V, E1 / 2: 1.20 lux · sec Example 2 Pigment 2 V ₀ : −700 V, E1 / 2: 1.10 lux · sec Example 3 Pigment 3 _{V 0: -720V, E1 / 2} : 1.30 lux · sec example 4 pigment _{4 V 0: -700V, E1 /} 2: 1.25 lux · sec example 5 pigment 8 V _0: -690V, E1 / 2: 1.35 lux · sec example 6 pigment _{9 V 0: -700V, E1 /} 2: 1.10 lux · sec example 7 pigment _{10 V 0: -700V, E1 /} 2: 1.30 lux · sec example 8 pigment _{14 V 0: -690V, E1 /} 2: 1.30 lux · sec example 9 pigment _{18 V 0: -700V, E1 /} 2: 1.10 lux · sec example 10 pigment 24 V _0: -700V, E1 / 2: 1.40 lux / sec Example 11 Pigment _{37 V 0: -700V, E1 /} 2: 0.75 lux · sec Example 12 Pigment _{40 V 0: -710V, E1 /} 2: 0.70 lux · sec Example 13 Pigment 42 V _0: - 700V, E1 / 2: 1.00 lux · sec example 14 pigment _{43 V 0: -690V, E1 /} 2: 1.35 lux · sec example 15 pigment _{46 V 0: -700V, E1 /} 2: 1. 30 lux / second Example 16 Pigment 56 V ₀ : -700 V, E1 / 2: 1.20 lux / second Example 17 Pigment 62 V ₀ : -700 V, E1 / 2: 1.25 lux / second Example 18 Pigment _{65 V 0: -710V, E1 /} 2: 1.45 lux · sec example 19 pigment _{66 V 0: -700V, E1 /} 2: 1.45 lux · sec example 20 pigment 68 V _0: -700V, E1 / 2: 1.40 ru Box · sec Example 21 Pigment _{69 V 0: -700V, E1 /} 2: 1.10 lux · sec Example 22 Pigment _{70 V 0: -700V, E1 /} 2: 1.45 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 17 below. The charging characteristics were evaluated.
The results are shown.

[Table 17]

Comparative Example 1 Comparative Pigment 1 V ₀ : -700 V, E1 / 2: 3.55 lux · sec Comparative Example 2 Comparative Pigment 2 V ₀ : -680 V, E1 / 2: 2.70 lux · sec From these results It can be seen that the electrophotographic photoreceptor of the present invention has sufficient charging ability and excellent sensitivity.

Examples 23 to 35 The electrophotographic photosensitive member prepared in Example 1 was provided 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 variation amount ΔV _D of the dark portion potential and the variation amount ΔV _L of the bright portion potential after repeated use 5,000 times were measured. Examples 2, 3,
4, 5, 6, 7, 8, 9, 11, 12, 13, and 17
The electrophotographic photosensitive member prepared in the above was evaluated in the same manner. 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 23 ΔV _D : −5 V, ΔV _L : +5 V Example 24 ΔV _D : −5 V, ΔV _L : 0 V Example 25 ΔV _D : −10 V, ΔV _L : +5 V Example 26 ΔV _D : −5 V , ΔV _L : 0 V Example 27 ΔV _D : 0 V, ΔV _L : +5 V Example 28 ΔV _D : 0 V, ΔV _L : +5 V Example 29 ΔV _D : 0 V, ΔV _L : +10 V Example 30 ΔV _D : −10 V, ΔV _L : +5 V Example 31 ΔV _D : 0 V, ΔV _L : +10 V Example 32 ΔV _D : +5 V, ΔV _L : +5 V Example 33 ΔV _D : 0 V, ΔV _L : +5 V Example 34 ΔV _D : −5 V, ΔV _L : +5 V Example 35 ΔV _D : −10 V, ΔV _L : 0 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 23, the potential fluctuation during repeated use was measured. The results are shown. Comparative Example 3 ΔV _D : −50 V, ΔV _L : +60 V Comparative Example 4 ΔV _D : −90 V, ΔV _L : +75 V From the above results, it can be seen that the electrophotographic photoreceptor of the present invention has a small potential fluctuation when repeatedly used. .

Example 36 A subbing layer of polyvinyl alcohol having a thickness of 0.4 μm was formed on the aluminum surface of an aluminum-deposited polyethylene terephthalate film. The dispersion liquid of the disazo pigment used in Example 2 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.

Next, a styryl compound 4.5 of the following structural formula
g

Embedded image A solution prepared by dissolving 5 g of polycarbonate (weight average molecular weight: 35,000) in 40 g of tetrahydrofuran was applied on the charge generation layer and dried to form a charge transport layer having a thickness of 18 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 23. The results are shown. V ₀ : -680 V, E1 / 2: 1.05 lux · sec ΔV _D : 0 V, ΔV _L : +5 V

Example 37 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 2 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: 1.60 lux · sec.

Example 38 On the charge generation layer prepared in Example 2, 4.5 g of 2,4,7-trinitro-9-fluorenone and 4.5 g of poly-4,4'-dioxydiphenyl-2,2-propanecarbonate A solution prepared by dissolving 5 g of a polymer (molecular weight: 300,000) in 50 g of tetrahydrofuran is applied with a Myer bar, and the film thickness after drying is 21 μm.
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 : +690 V, E1 / 2: 3.30 lux / sec

Example 39 0.5 g of Pigment 2 was dispersed in a paint shaker together with 9.5 g of cyclohexanone for 5 hours. A solution prepared by dissolving 4.5 g of the same charge transporting material as used in Example 1 and 5 g of polycarbonate in 40 g of tetrahydrofuran was added thereto.
I stayed for another hour. The coating solution thus prepared was applied to an aluminum support with a Myer bar and dried to form a film having a thickness of 1%.
An 8 μm 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 : +675 V, E1 / 2: 3.80 lux / sec

[0043]

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) and / or the general formula (2). Electrophotographic photoreceptor. General formula (1) General formula (2) In the formula, A ₁ and A ₂ are the same or different and are represented by the general formula (3)
Represents a coupler residue. General formula (3) In the formula, X represents a residue necessary for condensing with a benzene ring to form a polycyclic aromatic ring or a heterocyclic ring, Z represents an oxygen atom or a sulfur atom, and R ₁ and R ₂ 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;
R ₁ and R ₂ 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 / or (2) 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.