JPH07244392A - Electrophotographic photoreceptor and electrophotographic device - Google Patents

Abstract

PURPOSE:To ensure practically high sensitivity characteristics and stable potential characteristics in repetitive use by using a trisazo pigment having a specified structure in a photosensitive layer. CONSTITUTION:This electrophotographic photoreceptor has a photosensitive layer contg. a trisazo pigment represented by formula I (where each of Cp1 and Cp2 is a residue of a coupler having a phenolic hydroxyl, group, Cp1 and Cp2 may be different from each other and Z1 is O or S) or a trisazo pigment represented by formula II (where R1 is H, cyano, alkyl or aryl which may have a substituent, Ar is p- or m-phenylene, each of Cp1-Cp3 is a residue of a coupler having a phenolic hydroxyl group, Cp1-Cp3 may be different from one another and Z1 is O or S). The efficiency of generation or injection of electric charge carriers in the photosensitive layer is improved and such characteristics as superior sensitivity and potential stability at the time of repeated use are ensured.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member and an electrophotographic apparatus equipped with the electrophotographic photosensitive member.

[0002]

2. Description of the Related Art Conventionally, inorganic photoconductive substances such as selenium, cadmium sulfide and zinc oxide have been widely used as electrophotographic photoreceptors.

An electrophotographic photoreceptor using an organic photoconductive material has a good film-forming property and can be produced by coating. Therefore, there is an advantage that an electrophotographic photoreceptor having extremely high productivity can be provided at a low cost. Also, depending on the selection of dyes and pigments used,
It has the advantage of being able to freely control the color sensitivity and has been extensively studied so far. Particularly recently, by the development of a function-separated photoreceptor in which a charge generation layer containing an organic photoconductive dye or pigment and a charge transport layer containing a photoconductive polymer or an organic photoconductive substance of a low molecular weight are laminated. The sensitivity and durability, which have been considered to be the drawbacks of conventional organic electrophotographic photoreceptors, have been remarkably improved.

Azo pigments have excellent photoconductivity, and pigments having various characteristics can be easily obtained by combining the azo component and the coupler component. Therefore, many azo pigments have been proposed so far. For example, JP-A-56-
No. 143437, JP-A No. 54-22834, JP-A No. 60-202443, JP-A No. 64-2059, and JP-A No. 63-17456.

However, conventional electrophotographic photoreceptors using disazo pigments are not always sufficient in terms of sensitivity and potential stability during repeated use, and very few materials have been put to practical use. Only.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel photoconductive material, an electrophotographic photoreceptor having practical high sensitivity characteristics and stable potential characteristics upon repeated use. An object of the present invention is to provide an electrophotographic apparatus including a photographic photosensitive member.

[0007]

The present invention is an electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer contains a trisazo pigment represented by the general formula (1). It is composed of an electrophotographic photoreceptor. General formula (1)

[Chemical 4] In the formula, Cp ₁ , Cp ₂ and Cp ₃ represent a coupler-containing group having the same or different phenolic hydroxyl groups, and Z ₁ represents an oxygen atom or a sulfur atom.

The present invention also provides an electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer contains a trisazo pigment represented by the general formula (2). Composed of. General formula (2)

[Chemical 5] In the formula, R ₁ represents a hydrogen atom, a cyano group, an alkyl group or an aryl group which may have a substituent, Ar represents p-phenylene or m-phenylene, and Cp ₁ , Cp ₂
And Cp ₃ represent a coupler-containing group having the same or different phenolic hydroxyl groups, and Z ₁ represents an oxygen atom or a sulfur atom.

The present invention further provides an electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer contains a trisazo pigment represented by the general formula (3). Composed of. General formula (3)

[Chemical 6] In the formula, R ₁ represents a hydrogen atom, a cyano group, an alkyl group or an aryl group which may have a substituent, Ar represents p-phenylene or m-phenylene, and Cp ₁ , Cp ₂
And Cp ₃ represent coupler-containing groups having the same or different phenolic hydroxyl groups.

A coupler having a phenolic hydroxyl group represented by the above Cp ₁ , Cp ₂ and Cp _3- A preferred example of the residual group is a coupler represented by the following general formulas (4) to (9).
An example is Sanuki. General formula (4)

[Chemical 7] General formula (5)

[Chemical 8] General formula (6)

[Chemical 9] General formula (7)

[Chemical 10] General formula (8)

[Chemical 11] General formula (9)

[Chemical 12]

General formulas (4), (5), (6) and (7)
X in the formula is a polycyclic aromatic ring such as a naphthalene ring, an anthracene ring, a carbazole ring, a benzcarbazole ring, or a dibenzocarbazole ring which may be condensed with a benzene ring to have a substituent, or a heterocyclic ring. Represents a residue necessary for formation, Z ₂ in the general formulas (4) and (6) represents an oxygen atom or a sulfur atom, and n in the general formula (4) represents an integer of 0 or 1. R ₂ and R _{3 in the} general formulas (4) and (5) are each a hydrogen atom, an alkyl group which may have a substituent, an aryl group,
It represents an aralkyl group or a heterocyclic group, and R ₂ and R ₃ may be bonded to a nitrogen atom to form a cyclic amino group containing a nitrogen atom in the ring, and in general formulas (6) and (7) R
₄ represents a hydrogen atom, an alkyl group which may have a substituent, an aryl group, an aralkyl group or a heterocyclic group, and R ₅ in the general formula (8) represents an alkyl group which may have a substituent. Represents an aryl group, an aralkyl group or a heterocyclic group, and Y in the general formula (9) is a divalent aromatic hydrocarbon which may have a substituent or a divalent aromatic group which contains a nitrogen atom in the ring. Represents a heterocyclic group, for example, o-phenylene, o-naphthylene, perinaphthylene, 1,2-anthrylene, 3,4-pyrazol-diyl, 2,3-pyridinediyl, 4,5-pyridinediyl, 6,7-indazo. And divalent groups such as -rudiyl and 6,7-quinolinediyl.

Alkyl groups represented by R _{1 to} R ₅ in the general formulas (2) to (8) are groups such as methyl, ethyl and propyl, and aryl groups are phenyl and naphthyl.
Examples thereof include groups such as anthryl, and general formulas (4) to (8)
Examples of the aralkyl group represented by R _{2 to} R ₅ include groups such as benzyl and phenethyl, and examples of the heterocyclic group include groups such as pyridyl, thionyl, thiazoyl, carbazoyl, benzimidazolyl and benzothiazolyl, and a nitrogen atom in the ring. Examples of the cyclic amino group containing include pyrrole, pyrroline, pyridine, indole, indoline, carbazo-
Groups such as benzyl, imidazole, pyrazol, pyrazoline, oxazine and phenoxazine.

The substituent which the above-mentioned group may have is an alkyl group such as methyl, ethyl or propyl, fluorine,
Examples thereof include halogen atoms such as chlorine, bromine and iodine, acyl groups such as acetyl and benzyl, alkylamino groups such as dimethylamino and diethylamino, phenylcarbamoyl groups, nitro groups, cyano groups and halomethyl groups such as trifluoromethyl.

In the general formulas (1) to (3), Cp ₁ ,
The general formula in which Cp ₂ and Cp ₃ are the general formula (4), (5) or (6), and X in the formula is a coupler-containing group which is condensed with a benzene ring to form a benzcarbazole ring. The trisazo pigments represented by (1) to (3) have an absorption region extending to the near infrared region, and thus are suitable as a charge generating substance for a semiconductor laser.

Specific preferred examples of the trisazo pigments represented by the general formulas (1) to (3) are listed in Tables 1 to 25, but the trisazo pigment used in the present invention is not limited thereto.

The examples of the pigments in the table are the basic structures of the trisazo pigments represented by the general formulas (1) to (3), and the entire structure of the pigment is described by showing only the changed portions. .

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

[Table 7]

[Table 8]

[Table 9]

[Table 10]

[Table 11]

[Table 12]

[Table 13]

[Table 14]

[Table 15]

[Table 16]

[Table 17]

[Table 18]

[Table 19]

[Table 20]

[Table 21]

[Table 22]

[Table 23]

[Table 24]

[Table 25]

The trisazo pigments represented by the general formulas (1) to (3) are hexazolated from the corresponding triamine by a conventional method and coupled with a coupler in an aqueous system in the presence of an alkali, or a hexazonium salt is fluorinated. Or N, N-dimethylformamide,
It can be easily synthesized by coupling with a coupler in the presence of a base such as sodium acetate, triethylamine and N-methylmorpholine in an organic solvent such as dimethyl sulfoxide. In the above-mentioned trisazo pigment, in order to synthesize a different coupler-a trisazo pigment having a leaving group, one coupler is first added to 1 mol of the above-mentioned hexazonium salt.
One mole was coupled, then the other coupler-1 mole was coupled, and the other coupler-1
Synthesized by coupling 1 mol, or by protecting one or two amino groups of triamine with an acetyl group or the like, and tetrazating or diazotizing this,
After coupling one coupler, the protecting group is hydrolyzed with hydrochloric acid or the like, and this is again diazotized or tetrazolated and one coupler is coupled to synthesize.

Synthesis Example 1 (Synthesis of Pigment Example 1) 300 ml Beaker, 150 ml of water, 30 ml of concentrated hydrochloric acid
(0.35 mol)

[Chemical 13] Charge 9.68 g (0.032 mol), cool to 0 ° C., and add 7.0 g (0.102 mol) of sodium nitrite to water 10
The liquid dissolved in ml was added dropwise over 10 minutes while maintaining the liquid temperature at 5 ° C. After stirring for 15 minutes, carbon filtration was performed, and a solution prepared by dissolving 15.8 g (0.144 mol) of sodium borofluoride in 120 ml of water was added dropwise to this solution with stirring to precipitate the borofluoride salt. It was collected by filtration, washed with cold water, washed with acetonitrile, and dried under reduced pressure at room temperature. Yield 15.9
0 g, yield 83%.

Next, 500 ml of N, N-dimethylformamide (DMF) was placed in a 1 liter beaker to dissolve 10.97 g (0.042 mol) of naphthol AS, and after cooling the liquid temperature to 5 ° C. , The previously obtained borofluoride salt 8.38
g (0.014 mol) was dissolved, and then 4.7 g (0.046 mol) of triethylamine was added dropwise over 5 minutes. Two
After stirring for an hour, the precipitated pigment was collected by filtration, washed with DMF four times and water three times, and then freeze-dried. Yield 15.0 g, yield 95%.

Synthesis Example 2 (Synthesis of Pigment Example 25) 300 ml
150 ml of water and 20 ml of concentrated hydrochloric acid (0.23 mol) were added to a beaker.

[Chemical 14] 11.28 g (0.032 mol) was added, the mixture was cooled to 0 ° C., and 7.0 g (0.102 mol) of sodium nitrite was added to 10 parts of water.
The liquid dissolved in ml was added dropwise over 10 minutes while maintaining the liquid temperature at 5 ° C. After stirring for 15 minutes, carbon filtration was performed, and a solution prepared by dissolving 15.8 g (0.144 mol) of sodium borofluoride in 120 ml of water was added dropwise to this solution with stirring to precipitate the borofluoride salt. It was collected by filtration, washed with cold water, washed with acetonitrile, and dried under reduced pressure at room temperature. Yield 14.1
2 g, yield 68%.

Next, 500 ml of N, N-dimethylformamide (DMF) was placed in a 1-liter beaker, 10.97 g (0.042 mol) of naphthol AS was dissolved, and the liquid temperature was cooled to 5 ° C. , 8.8 g of the borofluoride salt previously obtained
(0.014 mol) was dissolved, and then 4.7 g (0.046 mol) of triethylamine was added dropwise over 5 minutes. After stirring for 2 hours, the precipitated pigment was collected by filtration, washed with DMF four times and water three times, and then freeze-dried. Yield 13.2 g, 80% yield.

Synthesis Example 3 (Synthesis of Pigment Example 62) 300 ml beaker, water 150 ml, concentrated hydrochloric acid 20 ml
(0.23 mol)

[Chemical 15] Charge 10.40 g (0.032 mol), cool to 0 ° C., and add 7.0 g (0.102 mol) of sodium nitrite to water 10
The liquid dissolved in ml was added dropwise over 10 minutes while maintaining the liquid temperature at 5 ° C. After stirring for 15 minutes, carbon filtration was performed, and a solution prepared by dissolving 15.8 g (0.144 mol) of sodium borofluoride in 120 ml of water was added dropwise to this solution with stirring to precipitate the borofluoride salt. It was collected by filtration, washed with cold water, washed with acetonitrile, and dried under reduced pressure at room temperature. Yield 14.0
g, 72% yield.

Next, 500 ml of N, N-dimethylformamide (DMF) was placed in a 1-liter beaker, and 2-hydroxy-3-naphthoic acid-2'-chloroanilide 1 was added.
After dissolving 2.5 g (0.042 mol) and cooling the liquid temperature to 5 ° C., 8.5 g (0.014) of the previously obtained borofluoride salt was obtained.
Mol), and then 4.7 g of triethylamine
(0.046 mol) was added dropwise over 5 minutes. After stirring for 2 hours, the precipitated pigment was collected by filtration, washed with DMF four times and water three times, and then freeze-dried. Yield 13.1g, Yield 75
%.

The electrophotographic photosensitive member of the present invention has a photosensitive layer containing a trisazo pigment represented by the general formula (1), (2) or (3) on a conductive support. The form of the photosensitive layer may be any known form, but a function-separated type photosensitive layer in which a layer containing the trisazo pigment is used as a charge generation layer and a charge transport layer containing a charge transport substance is laminated Particularly preferred.

For the charge generation layer, a coating solution prepared by dispersing the above-mentioned trisazo pigment in a suitable solvent together with a binder resin,
It can be formed by coating on a conductive support by a known method, and its film thickness is preferably 5 μm or less, preferably 0.1 to 1 μm.

The binder resin used at this time is selected from a wide range of insulating resins or organic photoconductive polymers, but it is not limited to polyvinyl butyral and polyvinyl benzal.
Resin, polyarylate, polycarbonate, polyester, phenoxy resin, cellulose resin, acrylic resin,
Polyurethane or the like is preferable, and the content of the binder resin in the charge generation layer is 80% by weight or less, preferably 40% by weight or less.

The solvent used dissolves the above resin,
It is preferable to select from those that do not dissolve the charge transport layer and the undercoat layer described below, such as tetrahydrofuran, ethers such as 1,4-dioxane, ketones such as cyclohexanone and methyl ethyl ketone, N, N-dimethylformamide and the like. Amides, esters such as methyl acetate and ethyl acetate, aromatic hydrocarbon compounds such as toluene, xylene and monochlorobenzene, alcohols such as methanol, ethanol and 2-propanol, chloroform and chloride Aliphatic halogenated hydrocarbon compounds such as methylene and the like can be mentioned.

The charge transport layer is laminated on or under 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 charge carriers. The charge-transporting layer is formed by dissolving a charge-transporting substance in a solvent together with a suitable binder resin, if necessary, and applying it, and the film thickness thereof is generally 5 to 40 μm, preferably 1 μm.
It is preferably 5 to 30 μm.

The charge transport material includes an electron transport material and a hole transport material, and examples of the electron transport material include, for example, 2,
Examples 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. As the hole-transporting substance, polycyclic aromatic compounds such as pyrene and anthracene, carbazole, indole, imidazole, oxazole, thiazole, oxadiazol, pyrazole,
Heterocyclic compounds such as pyrazoline, thiadiazole and triazol compounds, p-diethylaminobenzaldehyde-N, N-diphenylhydrazone, N, N-diphenylhydrazino-3-methylidene-9-ethylcarbazo-
And other hydrazone compounds, α-phenyl-4′-
Styryl compounds such as N, N-diphenylaminostilbene, 5- [4- (di-p-tolylamino) benzylidene] -5H-dibenzo [a, d] cycloheptene, benzidine compounds, triarylmethane compounds, triphenyl Polymers having amine, tritolylamine or a group consisting of these compounds in the main chain or side chain
(For example, poly-N-vinylcarbazol, polyvinyl anthracene, etc.) can be mentioned. In addition to these organic charge transport materials, inorganic materials such as selenium, selenium tellurium, amorphous silicon, and cadmium sulfide can also be used. Further, these charge transport substances can be used alone or in combination of two or more.

When the charge transport material does not have a film-forming property, a suitable binder resin can be used, and examples thereof include acrylic resin, polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer, polyacrylamide, polyamide,
Examples thereof include insulating resins such as chlorinated rubber and organic photoconductive polymers such as poly-N-vinylcarbazole and polyvinylanthracene.

Examples of the conductive support used in the present invention include aluminum, aluminum alloys, copper,
Zinc, stainless steel, titanium, nickel, indium, gold or platinum is used. In addition, plastics formed by coating these metals or alloys by vacuum deposition (eg polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, etc.)
And conductive particles (eg carbon black, silver particles, etc.)
It is possible to use a support in which the above is coated on a plastic or metal substrate with a suitable binder resin, or a support in which conductive particles are impregnated in plastic or paper.

An undercoat layer having a barrier function and an adhesive function may be provided between the conductive support and the photosensitive layer.
The thickness of the undercoat layer is 5 μm or less, preferably 0.1 to 3 μm
m is suitable. The undercoat layer is casein, polyvinyl alcohol, nitrocellulose, polyamide (nylon 6,
Nylon 66, Nylon 610, Copolymer Nylon, N-
Alkoxymethylated nylon, etc.), polyimide, polyurethane, aluminum oxide, etc.

A protective layer may be provided on the photosensitive layer for the purpose of improving durability and environmental stability. The thickness of the protective layer is in the range of 0.2 to 10 μm, preferably 0.
It is in the range of 6 to 6.0 μm. As the resin used for the protective layer, polycarbonate, polyester, polyaryle
, Polystyrene, polyethylene, polypropylene, polyurethane, acrylic resin, epoxy resin, silicone resin, cellulose resin, polyvinyl chloride, phosphazene resin, melamine resin, polyamide, polyimide and vinyl chloride-vinyl acetate copolymer. Can be mentioned. These resins can be used alone or in combination of two or more kinds. When polymerizing after coating, an initiator may be included.

In order to control the resistance, the protective layer may contain conductive particles, and may be surface-treated if necessary. Examples of the conductive particles include metals, metal oxides and carbon black. As the surface treatment agent, a silane coupling agent, silicone oil,
Examples thereof include surfactants. Examples of the metal include aluminum, zinc, copper, chromium, nickel, stainless steel, silver, and the like, or those obtained by vapor-depositing these metals on the surface of plastic particles. These may be used alone or in combination of two or more. Two
When using in combination of two or more species, even if simply mixed,
It may be in the form of solid solution or fusion.

Another specific example of the present invention is an electrophotographic photoreceptor containing the above-mentioned trisazo pigment and a charge transport material in the same layer. The electrophotographic photosensitive member of this example can be formed by applying a liquid in which a trisazo pigment and a charge transporting substance are dispersed in an appropriate resin solution onto a conductive support and drying the liquid. As for the protective layer, in addition to the above methods, beam processing, vacuum deposition and the like can be used.

In any of the electrophotographic photoreceptors, the crystal form of the trisazo pigment represented by the general formulas (1), (2) and (3) may be amorphous or crystalline, If necessary, two or more of the above-mentioned trisazo pigments may be combined or used in combination with a known charge generating substance.

The electrophotographic photoreceptor of the present invention can be used not only in electrophotographic copying machines, but also in laser beam printers, C
RT printer, LED printer, liquid crystal printer,
It can also be widely used in electrophotographic application fields such as laser plate making and facsimile.

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

FIG. 1 shows a schematic structure of a general transfer type electrophotographic apparatus using the drum type photoreceptor of the present invention. In the figure, reference numeral 1 denotes a drum type photosensitive member as an image bearing member, and a shaft 1
It is rotationally driven around a at a predetermined peripheral speed in the arrow direction.
The photosensitive member 1 is uniformly charged at its peripheral surface by a charging unit 2 at a predetermined positive or negative potential in the course of its rotation, and then at an exposure unit 3 an optical image exposure L (slit exposure Laser beam scanning exposure). As a result, electrostatic latent images corresponding to the exposed image are 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 from a paper feeding portion (not shown) between the photosensitive body 1 and the transfer means 5. Then, the image is sequentially transferred onto the surface of the transfer material P that is fed in synchronization with the above. The transfer material P which has received the image transfer is separated from the surface of the photoconductor and is introduced into the image fixing means 8 where it is subjected to image fixing and printed out as a copy (copy). The surface of the photoconductor 1 after the image transfer is cleaned by the cleaning means 6 by removing the transfer residual toner, and is subjected to the charge removal processing by the pre-exposure means 7 to be repeatedly used for image formation. As a uniform charging means 2 for the photoconductor 1, a corona charging device is generally widely used. Also, as the transfer device 5, corona transfer means is generally widely used. As an electrophotographic apparatus, a plurality of constituent elements such as the above-mentioned photoconductor, developing means, and cleaning means are integrally combined and configured as an apparatus unit, and this unit is detachably attached to the apparatus main body. You may comprise. For example, the photosensitive member 1 and the cleaning means 6 may be integrated into one device unit, and the device body may be detachable by using a guide means such as a rail. At this time, the above-mentioned apparatus unit may be configured with a charging means and / or a developing means. 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 an original, or the original is read and converted into a signal by a laser. -Beam scanning,
This is performed by driving the light emitting diode array or the liquid crystal shutter array.

[0040]

【Example】

Examples 1 to 10 Methanol 95 g of methoxymethylated nylon (number average molecular weight 32000) 5 g and alcohol soluble copolymerized nylon (number average molecular weight 29000) 10 g were placed on an aluminum support.
The solution dissolved in g was applied with a Mayer bar to form an undercoat layer having a film thickness after drying of 1 μm.

Next, 5 g of the pigment of Pigment Example 1 above was added to 95 g of cyclohexanone, butyral resin (butyralization degree: 6).
3 mol%) 2 g was added to the solution and 20
Time dispersed. This dispersion was applied onto the undercoat layer with a Meyer bar so that the film thickness after drying was 0.2 μm, to form a charge generation layer.

Then, 5 g of a hydrazone compound having the following structural formula

[Chemical 16] And polymethylmethacrylate (number average molecular weight 10,000
0) A solution prepared by dissolving 5 g of chlorobenzene in 40 g was applied on the charge generation layer with a Mayer bar so that the film thickness after drying was 20 μm to form a charge transport layer. Created the body.

Instead of Pigment Example 1, Pigment Examples 2, 3, 6,
Electrophotographic photoreceptors corresponding to Examples 2 to 10 were prepared in exactly the same manner as in Example 1 except that the pigments 9, 11, 18, 20, 23 and 24 were used.

Examples 11 to 20 In the same manner as in Example 1, an undercoat layer was formed on the aluminum support.

Next, an electrophotography of Example 11 was conducted in the same manner as in Example 1 except that the pigment of Pigment Example 25 was used and the charge transport layer was formed to have a thickness of 18 μm. A photoconductor was created.

Instead of Pigment Example 25, Pigment Examples 26, 28,
Examples 11 and 2 were carried out in the same manner as in Example 11 except that the pigments of 32, 34, 45, 51, 56, 67 and 70 were used.
An electrophotographic photosensitive member corresponding to 0 was prepared.

The electrophotographic photosensitive member thus prepared was manufactured by Kawaguchi Electric Co., Ltd., electrostatic copying paper tester (SP-42).
8) was negatively charged by -5 KV corona discharge, left in the dark for 1 second, and then exposed to light with an illuminance of 10 lux using a halogen lamp to evaluate the charging characteristics. As the charging characteristics, the surface potential V ₀ and the exposure amount E _1/2 required for the surface potential after being left in the dark to be attenuated to _1/2 were measured. Example 1: Pigment example 1, V ₀ : -709V,
E _1/2 : 1.95 lux · sec. Example 2: Pigment example 2, V ₀ : −792V,
E _1/2 : 1.15 lux · sec Example 3: Pigment example 3, V ₀ : -700V,
E _1/2 : 1.23 lux · sec. Example 4: Pigment example 6, V ₀ : -695V,
E _1/2 : 1.19 lux · sec. Example 5: Pigment example 9, V ₀ : −788V,
E _1/2 : 1.88 lux · second Example 6: Pigment Example 11, V ₀ : −820V,
E _1/2 : 1.32 lux · sec Example 7: Pigment Example 18, V ₀ : -735V,
E _1/2 : 1.08 lux · sec. Example 8: Pigment Example 20, V ₀ : −754V,
E _1/2 : 1.58 lux · sec Example 9: Pigment Example 23, V ₀ : −743V,
E _1/2 : 0.98 lux · sec Example 10: Pigment Example 24, V ₀ : -721V,
E _1/2 : 0.25 lux · second Example 11: Pigment Example 25, V ₀ : −853V,
E _1/2 : 1.85 lux · sec Example 12: Pigment Example 26, V ₀ : -800V,
E _1/2 : 1.31 lux · sec Example 13: Pigment Example 28, V ₀ : -780V,
E _1/2 : 1.45 lux · sec Example 14: Pigment Example 32, V ₀ : -750V,
E _1/2 : 1.23 lux · sec Example 15: Pigment Example 34, V ₀ : -782V,
E _1/2 : 1.28 lux · sec Example 16: Pigment Example 45, V ₀ : -850V,
E _1/2 : 1.08 lux · sec Example 17: Pigment Example 51, V ₀ : -768V,
E _1/2 : 1.05 lux · sec Example 18: Pigment Example 56, V ₀ : -788V,
E _1/2 : 1.55 lux · sec Example 19: Pigment Example 67, V ₀ : -795V,
E _1/2 : 1.29 lux · sec Example 20: Pigment Example 74, V ₀ : -803V,
E _1/2 : 1.15 lux · sec

Comparative Examples 1 and 2 Comparative Example 1 is the same as Example 1 except that the pigments of Comparative Pigment Examples 1 and 2 shown by the following structural formulas are used instead of Pigment Example 1 used in Example 1. Electrophotographic photoreceptors corresponding to Nos. 1 and 2 were prepared and the charging characteristics were evaluated by the same method as in Example 1. Comparative pigment example 1

[Chemical 17] Comparative pigment example 2

[Chemical 18] Comparative Example 1: V ₀ : -735V, E _1/2 : 5.3 lux · sec Comparative Example 2: V ₀ : −802V, E _1/2 : 25.0 lux · sec

Comparative Examples 3 and 4 Example 1 was repeated except that the pigments of Comparative Pigment Examples 3 and 4 represented by the following structural formulas were used in place of Pigment Example 25 used in Example 11:
Electrophotographic photoreceptors corresponding to Comparative Examples 3 and 4 were prepared in exactly the same manner as in Example 1, and the charging characteristics were evaluated in the same manner as in Example 1. Comparative pigment example 3

[Chemical 19] Comparative pigment example 4

[Chemical 20] Comparative Example 3: V ₀ : -690V, E _1/2 : 3.08 lux · second Comparative Example 4: V ₀ : −650V, E _1/2 : 2.95 lux · second

From these results, it is known that each of the electrophotographic photoreceptors of the present invention has sufficient charging ability and excellent sensitivity.

Examples 21 to 30 The electrophotographic photosensitive member prepared in Example 2 was equipped with a -6.5 KV corona charger, an exposure optical system, a developing device, a transfer charger, a static elimination exposure optical system and a cleaner. It was attached to the cylinder of the electrophotographic copying machine. Initial dark potential V _D and bright potential V _L
Are set near -700V and -200V respectively,
Variation of dark area potential after repeated use 000 times ΔV _D
Then, the fluctuation amount ΔV _L of the light portion potential was measured. Examples 3, 4,
The electrophotographic photoreceptors prepared in 5, 6, 11, 13, 15, 16 and 17 were also evaluated in the same manner. The negative sign in the fluctuation amount of the electric potential represents the decrease in the absolute value of the electric potential,
The positive symbol represents an increase in the absolute value of the electric potential. Example 21 ΔV _D : +5 V, ΔV _L : 0 V Example 22 ΔV _D : −10 V, ΔV _L : 0 V Example 23 ΔV _D : −5 V, ΔV _L : +5 V Example 24 ΔV _D : −5 V, ΔV _L : + 5V Example 25 ΔV _D : −5V, ΔV _L : + 5V Example 26 ΔV _D : + 10V, ΔV _L : + 10V Example 27 ΔV _D : + 5V, ΔV _L : + 15V Example 28 ΔV _D : + 10V , ΔV _L : + 5V Example 29 ΔV _D : + 10V, ΔV _L : −5V Example 30 ΔV _D : + 10V, ΔV _L : −5V

Comparative Examples 5 and 6 With respect to the electrophotographic photosensitive members prepared in Comparative Examples 2 and 3, the amount of potential fluctuation during repeated use was measured by the same method as in Example 21. Comparative Example 5 ΔV _D : −40 V, ΔV _L : +25 V Comparative Example 6 ΔV _D : −60 V, ΔV _L : ”50 V

From the results of Examples 21 to 30 and Comparative Examples 5 and 6, it is known that the electrophotographic photosensitive member of the present invention has little potential fluctuation during repeated use.

Example 31 Polyvinyl alcohol having a thickness of 0.5 μm on the aluminum surface of an aluminum vapor-deposited polyethylene terephthalate film.
An undercoat layer was formed. On top of this, a dispersion similar to the dispersion of the trisazo pigment used in Example 2 was applied to a Mayer bar.
And dried to form a charge generation layer having a thickness of 0.2 μm.

Next, 5 g of a styryl compound having the following structural formula

[Chemical 21] And polycarbonate (weight average molecular weight 55000) 5 g
Was dissolved in 40 g of tetrahydrofuran and applied on the charge generation layer and dried to form a charge transport layer having a film thickness of 20 μm to prepare an electrophotographic photoreceptor. The charging characteristics and the durability characteristics of this electrophotographic photosensitive member were evaluated by the same methods as in Examples 1 and 21. _{V O: -783V, E 1/2:} 1.32 lux-seconds _{ΔV D: + 10V, ΔV L} : + 5V

Example 32 The same operation as in Example 31 except that the same dispersion liquid as the trisazo pigment dispersion liquid used in Example 13 was used and the charge transport layer was formed to have a thickness of 18 μm. An electrophotographic photosensitive member was prepared and the charging property and durability property were evaluated in the same manner. _{V O: -865V, E 1/2:} 1.49 lux-seconds _{ΔV D: 0V, ΔV L:} + 5V

Example 33 An electrophotographic photosensitive member was prepared in the same manner as in Example 2 except that the charge generation layer and the charge transport layer in the electrophotographic photosensitive member prepared in Example 2 were coated in the reverse order. The charging characteristics were evaluated in the same manner as in Example 1. However, the charging was positive. V _O : + 735V, E _1/2 : 1.48 lux ・ sec

Example 34 Example 13 was repeated except that the charge generation layer and the charge transport layer in the electrophotographic photosensitive member prepared in Example 13 were coated in the reverse order.
An electrophotographic photosensitive member was prepared in the same manner as in 1. and the charging property was evaluated by the same method as in Example 1. However, the charging was positive. V _O : + 712V, E _1/2 : 1.65 lux ・ sec

Example 35 A charge generation layer was formed in the same manner as in Example 2,
2,4,7-trinitro-9-fluorenone 5
g and 5 g of poly-4,4'-dioxydiphenyl-2,2-propanecarbonate (molecular weight 300,000) dissolved in 50 g of tetrahydrofuran were applied and dried with a Mayer bar to give a charge having a film thickness of 18 μm. A transport layer was formed to prepare an electrophotographic photoreceptor. The charging property was evaluated by the same method as in Example 1. However, the charging was positive. V _O : + 735V, E _1/2 : 1.85 lux ・ sec

Example 36 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 35 except that the charge generation layer was formed in the same manner as in Example 13. V _O : + 650V, E _1/2 : 2.80 lux ・ sec

Example 37 0.5 g of the pigment of Pigment Example 2 was dispersed with 9.5 g of cyclohexanone in a paint shaker for 5 hours. 5 g of the charge transport material used in Example 1 and 5 g of polycarbonate
Was dissolved in 40 g of tetrahydrofuran and shaken for 1 hour. The prepared coating solution was coated on an aluminum support with a Mayer bar and dried to form a photosensitive layer having a film thickness of 20 μm. It was created. The charging property was evaluated by the same method as in Example 1. However, the charging was positive. V _O : + 766V, E _1/2 : 2.83 lux ・ sec

Example 38 Pigment The pigment of Example 28 was used, and the thickness of the photosensitive layer was 18 μm.
An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 37, except that the electrophotographic photosensitive member was formed in m. V _O : + 788V, E _1/2 : 3.25 lux ・ sec

[0063]

INDUSTRIAL APPLICABILITY In the electrophotographic photoreceptor of the present invention, by using the trisazo pigment having a specific structure in the photosensitive layer, either one or both of the charge carrier generation efficiency and the injection efficiency in the photosensitive layer is improved, A remarkable effect is obtained in that the characteristics are excellent in sensitivity and potential stability during repeated use. This effect is the same when the electrophotographic photosensitive member is applied to an electrophotographic apparatus.

[Brief description of drawings]

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Drum type photoconductor as an image bearing member (electrophotographic photoconductor of the present invention) 1a axis 2 corona charging device 3 exposure section 4 developing means 5 transfer means 6 cleaning means 7 pre-exposure means 8 image fixing means L optical image Exposure P Transfer material that received image transfer

Claims (9)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer contains a trisazo pigment represented by the general formula (1). General formula (1) In the formula, Cp ₁ , Cp ₂ and Cp ₃ represent a coupler-containing group having the same or different phenolic hydroxyl groups, and Z ₁ represents an oxygen atom or a sulfur atom. 2. An electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer contains a trisazo pigment represented by the general formula (2). General formula (2) In the formula, R ₁ represents a hydrogen atom, a cyano group, an alkyl group or an aryl group which may have a substituent, Ar represents p-phenylene or m-phenylene, and Cp ₁ , Cp ₂
And Cp ₃ represent a coupler-containing group having the same or different phenolic hydroxyl groups, and Z ₁ represents an oxygen atom or a sulfur atom. 3. An electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer contains a trisazo pigment represented by the general formula (3). General formula (3) In the formula, R ₁ represents a hydrogen atom, a cyano group, an alkyl group or an aryl group which may have a substituent, Ar represents p-phenylene or m-phenylene, and Cp ₁ , Cp ₂
And Cp ₃ represent coupler-containing groups having the same or different phenolic hydroxyl groups. 4. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer comprises at least two layers of a charge generating layer containing the trisazo pigment represented by the general formula (1) and a charge transporting layer. 5. The electrophotographic photosensitive member according to claim 2, wherein the photosensitive layer comprises at least two layers of a charge generating layer containing the trisazo pigment represented by the general formula (2) and a charge transporting layer. 6. The electrophotographic photosensitive member according to claim 3, wherein the photosensitive layer comprises at least two layers of a charge generating layer containing the trisazo pigment represented by the general formula (3) and a charge transporting layer. 7. An electrophotographic apparatus provided with the electrophotographic photosensitive member according to claim 1. 8. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 2. 9. An electrophotographic apparatus provided with the electrophotographic photosensitive member according to claim 3. [0001]