JP3167085B2 - Electrophotographic photoreceptor, process cartridge having the electrophotographic photoreceptor, and electrophotographic apparatus - 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, and more particularly, to an electrophotographic photosensitive member having a photosensitive layer containing a disazo compound having a specific structure. Further, the present invention relates to a process cartridge having the electrophotographic photosensitive member and an electrophotographic apparatus.

[0002]

2. Description of the Related Art An electrophotographic photoreceptor using an organic photoconductive substance has advantages such as extremely high productivity and relatively low cost, and in addition, appropriately selects dyes and pigments to be used. By doing so, there is an advantage that the color sensitivity can be freely controlled, and wide studies have been made so far. In particular, the function of laminating a charge generating layer containing a charge generating substance such as an organic photoconductive dye or a pigment and a charge transporting layer containing a charge transporting substance such as a photoconductive polymer or a low molecular organic photoconductive substance. The development of the separation type photoreceptor has made remarkable improvements in sensitivity and durability, which have been disadvantages of the conventional organic electrophotographic photoreceptor.

[0003] Among organic photoconductive materials, many azo pigments have excellent photoconductivity, and compounds having various characteristics can be relatively easily obtained by combining an amine component and a coupler component. Numerous compounds have been described, for example, in JP-A-58-194035, JP-A-61-215556, and JP-A-61-24176.
3, JP-A-63-17456, JP-A-63-17456
-259572 and JP-A-63-259670.

[0004]

However, with the recent demand for higher image quality and higher durability, an electrophotographic photoreceptor having higher sensitivity and more excellent electrophotographic characteristics even when repeatedly used. Is being considered.

An object of the present invention is to provide an electrophotographic photosensitive member having high sensitivity.

It is another object of the present invention to provide an electrophotographic photosensitive member which has excellent potential characteristics stably even when used repeatedly.

Another object of the present invention is to provide a process cartridge and an electrophotographic apparatus having the above-described electrophotographic photosensitive member.

[0008]

That is, the present invention relates to an electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer comprises a disazo pigment having a 1,2-benzofluorenone structure as a central skeleton. It is an electrophotographic photosensitive member characterized by containing.

Further, the present invention is a process cartridge and an electrophotographic apparatus having the above electrophotographic photosensitive member.

Among the disazo pigments used in the present invention, a disazo pigment represented by the following formula (1) is particularly preferred.

[0011]

[Outside 10] (Wherein, A ₁ and A ₂ are the same or different and represent a coupler residue having a phenolic hydroxyl group, and R _{1 to} R ₄ are the same or different and represent a hydrogen atom, a halogen atom, an alkyl group and an alkoxy group. Represents at least one selected group, and m and n represent 1, 2 or 3.)

The halogen atom represented by R _{1 to} R ₄ includes a fluorine atom, a chlorine atom and a bromine atom, the alkyl group includes a group such as methyl, ethyl and propyl, and the alkoxy group includes methoxy and ethoxy. And groups such as propoxy, but in the present invention,
R _{1 to} R ₄ are preferably hydrogen atoms.

The coupler residues represented by A ₁ and A ₂ are preferably represented by the following formulas (2) to (7).

[0014]

[Outside 11]

[0015]

[Outside 12]

X in the formulas (2), (3), (4) and (5) is condensed with a benzene ring to form a polycyclic aromatic ring such as a naphthalene ring and an anthracene ring, a carbazole ring, a benzocarbazole ring and a dibenzocarbazole. It shows the residues necessary to form a heterocyclic ring such as a ring.

Y in the formula (7) represents an arylene group or a divalent heterocyclic group containing a nitrogen atom in the ring. Specifically, o-phenylene, o-naphthylene, perinaphthylene,
1,2-anthrylene, 3,4-pyrazoldiyl,
2,3-pyridinediyl, 4,5-pyridinediyl,
Groups such as 6,7-indazolediyl and 6,7-quinolinediyl are included.

R ₅ , R ₆ , R _{7 in the} formulas (2) and (3)
And R ₈ represent a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, and a heterocyclic group, and R ₅ and R ₆ and R ₇
And R ₈ represent a residue which forms a cyclic amino group containing a nitrogen atom in the ring by bonding.

R ₉ , R ₁₀ and R in the formulas (4) and (5)
₁₁ represents a hydrogen atom, an alkyl group, an aryl group, an aralkyl group and a heterocyclic group.

R ₁₂ in the formula (6) represents an alkyl group, an aryl group, an aralkyl group and a heterocyclic group.

The above-mentioned alkyl groups are groups such as methyl, ethyl and propyl, the aryl groups are groups such as phenyl, naphthyl and anthryl, the aralkyl groups are groups such as benzyl and phenethyl, and the heterocyclic groups are pyridyl and thienyl. , Thiazolyl, carbazolyl, benzimidazolyl and benzothiazolyl. Examples of the cyclic amino group containing a nitrogen atom in the ring include groups such as pyrrolyl, indolyl, indolinyl, carbazolyl, imidazolyl, benzimidazolyl, pyrazolyl, phenothiazinyl and phenoxazinyl.

X, Y and R _{5 to} R ₁₂ may have a substituent, and the substituent which may be possessed is an alkyl group such as methyl, ethyl and propyl; methoxy, ethoxy and propoxy. A halogen atom such as fluorine, chlorine, bromine and iodine; an acyl group such as acetyl and benzoyl; an alkylamino group such as dimethylamino and diethylamino; a phenylcarbamoyl group; a nitro group; a cyano group; And a halomethyl group.

Z in the formulas (2) and (4) represents an oxygen atom or a sulfur atom.

P in the formula (2) represents 0 or 1.

In the present invention, A ₁ and A ₂ are represented by a formula selected from the group consisting of formulas (2), (3), (4) and (5), wherein X in the formula is fused to a benzene ring. When the disazo pigment is a coupler residue forming a benzocarbazole ring, the disazo pigment can be preferably used also as a charge generating material for a semiconductor laser because the sensitivity range extends to near the near infrared region.

Preferred examples of the disazo pigment represented by the formula (1) are enumerated below, but the disazo compound used in the present invention is not limited thereto. The exemplary pigments are represented by first showing a basic type and then showing only the structure of A ₁ and A ₂ which are the portions that change.

[0027]

[Outside 13]

[0028]

[Outside 14]

[0029]

[Outside 15]

[0030]

[Outside 16]

[0031]

[Outside 17]

[0032]

[Outside 18]

[0033]

[Outside 19]

[0034]

[Outside 20]

[0035]

[Outside 21]

[0036]

[Outside 22]

[0037]

[Outside 23]

[0038]

[Outside 24]

[0039]

[Outside 25]

[0040]

[Outside 26]

[0041]

[Outside 27]

[0042]

[Outside 28]

[0043]

[Outside 29]

[0044]

[Outside 30]

The disazo pigment represented by the formula (1) is
(A) the corresponding diamine is tetrazotized by a conventional method, and is coupled with a coupler in the presence of an alkali in an aqueous system,
(B) After the tetrazonium salt is converted into a borofluoride salt or a double zinc chloride salt, the presence of a base such as sodium acetate, triethylamine and N-methylmorpholine in an organic solvent such as N, N-dimethylformamide or dimethylsulfoxide. Below, it can be easily synthesized by coupling with a coupler.

In the case of preparing a disazo pigment in which A ₁ and A ₂ in the formula (1) are different coupler residues, (a) 1 mol of one coupler is first added to 1 mol of the above-mentioned tetrazonium salt. Coupling and then coupling one mole of the other coupler to synthesize (b)
Alternatively, one amino group of the diamine is protected with an acetyl group or the like, which is diazotized and coupled with one of the couplers.Then, the protecting group is hydrolyzed with hydrochloric acid or the like, which is again diazotized to form the other coupler. It can be synthesized by coupling.

Synthesis Example (Synthesis of Disazo Pigment Example 1 as Exemplified) 150 ml of water and 20 ml of concentrated hydrochloric acid were placed in a 300 ml beaker.
(0.23 mol) and the following diamine compound 8.3 g (0.
032 mol)

[0048]

[Outside 31] Cool to 0 ° C. and add 4.6 g of sodium sulfite into this solution
(0.067 mol) in 10 ml of water was added dropwise over 10 minutes while keeping the temperature at 5 ° C. or lower. After stirring for 15 minutes, the mixture was filtered with carbon, and a solution prepared by dissolving 10.5 g (0.096 mol) of sodium borofluoride in 90 ml of water was dropped into this solution with stirring, and the precipitated borofluoride was collected by filtration. After washing with cold water, washing with acetonitrile,
It dried under reduced pressure at room temperature. The yield was 13.6 g and the yield was 93.
%Met.

Next, 500 ml of N, N-dimethylformamide was placed in a 1 l beaker, and 11.1 g of the following coupler was added.
(0.042 mol),

[0050]

[Outside 32] Was dissolved and the solution temperature was cooled to 5 ° C., and then 9.2 g (0.020 mol) of the borofluoride obtained above was dissolved, and then 5.1 g (0.050 mol) of triethylamine was added dropwise over 5 minutes. did. After stirring for 2 hours, the precipitated pigment was collected by filtration,
After washing four times with N, N-dimethylformamide and three times with water, it was freeze-dried. The yield is 14.7 g and the yield is 91.
%Met. The results of the elemental analysis are shown below.

[0051]

[Table 1]

In the present invention, the photosensitive layer may be in any known form, but the layer containing the disazo pigment having a benzofluorenone structure of the present invention as a charge generating substance is defined as a charge generating layer. A function-separable type photosensitive layer in which a charge transporting layer containing a charge transporting substance is laminated thereon is particularly preferred.

The charge generation layer may be formed by vacuum-depositing the disazo pigment of the present invention on a conductive support or dispersing the disazo pigment in a suitable solvent together with a binder resin by a known method on a conductive support. And dried. The film thickness is preferably 5 μm or less, particularly preferably 0.1 to 1 μm.

The binder resin is selected from a wide range of insulating resins and organic photoconductive polymers, and includes polyvinyl butyral, polyvinyl benzal, polyarylate, polycarbonate, polyester, phenoxy resin, cellulose resin, acrylic resin and polyurethane. Are preferred. These resins may have a substituent, and the substituent is preferably a halogen atom, an alkyl group, an alkoxy group, a nitro group, a trifluoromethyl group, a cyano group, or the like. The amount of the binder resin used is preferably 80% by weight or less, and particularly preferably 40% by weight or less, based on the total weight of the charge generation layer.

The solvent 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, xylene and Aromatic hydrocarbon compounds such as monochlorobenzene; alcohols such as methanol, ethanol and 2-propanol; and aliphatic hydrocarbon compounds such as chloroform and methylene chloride.

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 and transporting them in the presence of an electric field. The charge transport layer can be formed by applying a solution in which a charge transport material is dissolved in a solvent together with an appropriate binder resin as necessary, and drying the solution. The thickness is preferably from 5 to 40 μm, particularly preferably from 15 to 30 μm.

The charge transport material is roughly classified into an electron transport material and a hole transport material. Examples of the electron transport material include, for example, 2,
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-based, indole-based, imidazole-based,
Oxazole, thiazole, oxadiazole,
Heterocyclic compounds such as pyrazole, pyrazoline, thiadiazole and triazole compounds; p-diethylaminobenzaldehyde-N, N-diphenylhydrazone and N, N-diphenylhydrazino-3-methylidene-
Hydrazone compounds such as 9-ethylcarbazole; α-
Styryl compounds such as phenyl-4'-N, N-diphenylaminostilbene and 5- [4- (di-p-tolylamino) benzylidene] -5H-dibenzo [a, b] cycloheptene; benzidine compounds; triarylmethane Triphenylamine compounds; and polymers having a group derived from these compounds in the main chain or side chain (for example, poly-N-vinylcarbazole and polyvinylanthracene). In addition to these organic charge transport materials, selenium, selenium-tellurium,
Inorganic materials such as amorphous silicon and cadmium sulfide can also be used. These charge transport materials may 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 resin can be used. Specifically, insulating resin such as acrylic resin, polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer, polyacrylamide, polyamide and chlorinated rubber, or poly-N-
Organic photoconductive polymers such as vinyl carbazole and polyvinyl anthracene are exemplified.

Another specific example of the present invention is an electrophotographic photoreceptor having a photosensitive layer containing the disazo pigment of the present invention and the above-described charge transporting substance in the same layer. This electrophotographic photoreceptor can be prepared by applying a solution obtained by dispersing and dissolving a disazo pigment and a charge transport material in an appropriate binder resin solution on a conductive support and drying the solution.

In any of the electrophotographic photoreceptors, the disazo pigment of the present invention may be used in combination of two or more, or in combination with a known charge generating substance, if necessary.

As the material of the conductive support used in the present invention, for example, aluminum, aluminum alloy, copper,
Zinc, stainless steel, vanadium, molybdenum, chromium,
Examples include titanium, nickel, indium, gold and platinum. In addition, plastics (eg, polyethylene,
A support such as polypropylene, polyvinyl chloride, polyethylene terephthalate and an acrylic resin, or a support in which conductive particles (eg, carbon black and silver particles, etc.) are coated on a plastic, metal or alloy as described above together with a suitable binder resin; Alternatively, a support or the like in which conductive particles are impregnated in plastic or paper can be used. Examples of the shape include a drum shape, a sheet shape, a belt shape, and the like, and a shape most suitable for an applied electrophotographic apparatus is preferable.

In the present invention, 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 preferably 5 μm or less, and particularly preferably 0.1 to 3 μm. Examples of the material of the undercoat layer include casein, polyvinyl alcohol, nitrocellulose, polyamide (eg, nylon 6, nylon 66, nylon 610, copolymerized nylon and alkoxymethylated nylon), polyurethane, and aluminum oxide.

In the present invention, a resin layer as a protective layer, a resin layer containing conductive particles or a charge transport material, or the like is used for the purpose of protecting the photosensitive layer from external mechanical and chemical adverse effects. Can be provided on the photosensitive layer.

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.

FIG. 1 shows a schematic configuration of an electrophotographic apparatus using the electrophotographic photosensitive member of the present invention.

In FIG. 1, reference numeral 1 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is driven to rotate around an axis 1a at a predetermined peripheral speed in a direction indicated by an arrow. The photosensitive member 1 is uniformly charged with a predetermined positive or negative potential on its peripheral surface by a charging means 2 in the course of rotation, and then the exposure section 3 is subjected to slit exposure or laser beam scanning by an image exposure means (not shown). It receives light image exposure L such as exposure. In this way, an electrostatic latent image corresponding to the exposure image is sequentially formed on the peripheral surface of the photoconductor.

The formed electrostatic latent image is then transferred to developing means 4
The toner developed image is transferred from a paper supply unit (not shown) to the transfer material P fed between the photoconductor 1 and the transfer unit 5 in synchronization with the rotation of the photoconductor 1 by a transfer unit. 5 are sequentially transferred.

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.

After the transfer of the image, the surface of the photoreceptor 1 is cleaned and cleaned by the cleaning unit 6 to remove the untransferred toner. Further, the surface of the photoreceptor 1 is subjected to a static elimination process by the pre-exposure unit 7 and then used repeatedly for image formation. .

In the present invention, among the above-mentioned components such as the electrophotographic photosensitive member 1, the charging means 2, the developing means 4 and the cleaning means 6, a plurality of components are integrally connected as a process cartridge. The process cartridge may be configured to be detachable from an image forming apparatus main body such as a copying machine or a laser beam printer. For example, at least one of the charging unit 2, the developing unit 4, and the cleaning unit 6 is integrally supported together with the photoreceptor to form a cartridge, and a process cartridge that can be attached to and detached from the apparatus main body by using a guide unit such as a rail of the apparatus main body. Good.

In the case where the electrophotographic apparatus is used as a copying machine or a printer, the light image exposure L involves irradiating the photosensitive member with reflected light or transmitted light from the original, or reading the original with a sensor. A signal is formed, and scanning of a laser beam, driving of an LED array, driving of a liquid crystal shutter array, and the like are performed in accordance with the signal to irradiate the photosensitive member with light.

On the other hand, when used as a facsimile printer, the light image exposure L is an exposure for printing received data. FIG. 2 is a block diagram showing an example of this case.

The controller 11 controls the image reading unit 10 and the printer 19. The whole controller 11 is CP
It is controlled by U17. The read data from the image reading unit is transmitted to the partner station through the transmission circuit 13. Data received from the partner station is sent to the printer 19 through the receiving circuit 12. Predetermined image data is stored in the image memory. The printer controller 18 is the printer 1
9 is controlled. 14 is a telephone.

The image received from the line 15 (image information from a remote terminal connected via the line) is demodulated by the receiving circuit 12 and then decoded by the CPU 17 and sequentially stored in the image memory 16. Is stored. When the image of at least one page is stored in the memory 16, the image of the page is recorded. The CPU 17 is a memory 1
6, one page of image information is read out, and the decoded one page of image information is sent to the printer controller 18. The printer controller 18 receives 1
When the image information of the page is received, the printer 19 is controlled to record the image information of the page. CPU17
Is receiving the next page during recording by the printer 19.

Thus, the reception and recording of the image are performed.

Hereinafter, the present invention will be described in more detail by way of examples.

[0077]

【Example】

Example 1 5 g of methoxymethylated nylon (weight average molecular weight 32,000) and alcohol-soluble copolymerized nylon (weight average molecular weight 29,000) 1 on an aluminum substrate
A solution prepared by dissolving 0 g in 95 g of methanol was applied with a Meyer bar, and an undercoat layer having a dried film thickness of 1 μm was formed.

Next, 5 g of Disazo Pigment Example 1 was added to 95 g of cyclohexanone with a butyral resin (butyralization degree of 63).
(Mol%, weight average molecular weight: 35,000) was dissolved in the solution and dispersed by using a sand mill for 20 hours. This dispersion was applied on a subbing layer with a Meyer bar and dried to form a charge generation layer having a thickness of 0.2 μm.

Then, 5 g of a hydrazone compound represented by the following formula:

[0080]

[Outside 33] And polymethyl methacrylate (number average molecular weight 100,0
00) A solution in which 5 g was dissolved in 40 g of monochlorobenzene was applied to the charge generation layer with a Meyer bar, and dried to form a charge transport layer having a thickness of 20 μm.

The thus prepared electrophotographic photosensitive member was negatively charged by a corona discharge of -5 KV using an electrostatic copying paper tester (SP-428, Kawaguchi Electric Co., Ltd.) and left in a dark place for 1 second. After that, the resultant was exposed to light having an illuminance of 10 lux using a halogen lamp, and the charging characteristics were evaluated. As the charging characteristics, the exposure amount required to attenuate the surface potential V ₀ immediately after charging and the surface potential after being left in a dark place for one second to half, that is, the sensitivity (E1
/ 2) was measured. The results are shown in Table 1.

Examples 2 to 18 Electrophotographic photosensitive members were prepared and evaluated in the same manner as in Example 1 except that the disazo pigments shown in Table 1 were used in place of Example 1. The results are shown in Table 1.

[0083]

[Table 2]

Comparative Examples 1 to 6 Electrophotographic photosensitive members were prepared and evaluated in the same manner as in Example 1 except that the following comparative pigments A to F were used in place of Disazo Pigment Example 1. The results are shown in Table 2.

[0085]

[Outside 34]

[0086]

[Outside 35]

[0087]

[Table 3]

From these results, it can be seen that all of the electrophotographic photosensitive members of the present invention have sufficient charging ability and excellent sensitivity.

Examples 19 to 30 An electrophotographic photoreceptor prepared in Example 1 was provided with a -6.5 KV corona charger, an exposure optical system, a developing device, a transfer charger, a charge removing exposure optical system, and a cleaner. Affixed to cylinder of copier.

[0090] After the initial dark potential V _D and the light portion potential V _L were set near -700V and -200V, respectively, 5,
After repeated use 000 times, the durability was evaluated by measuring the variation ΔV _D of the dark portion potential and the variation ΔV _L of the bright portion potential after the initial and repeated use. The results are shown in Table 3. Note that a negative sign in the fluctuation amount of the potential indicates that the absolute value of the potential has decreased, and a positive sign indicates that the absolute value of the potential has increased.

Examples 2, 3, 4, 5, 8, 10, 12,
The electrophotographic photoreceptors prepared in Nos. 14, 16, 17 and 18 were similarly evaluated. The results are shown in Table 3.

[0092]

[Table 4]

Comparative Examples 7 to 12 The electrophotographic photosensitive members prepared in Comparative Examples 1 to 6 were evaluated in the same manner as in Example 19. The results are shown in Table 4.

[0094]

[Table 5]

From the results of Examples 19 to 30 and Comparative Examples 7 to 12, it can be seen that the electrophotographic photosensitive member of the present invention has little potential fluctuation upon repeated use.

Example 31 A subbing layer of polyvinyl alcohol having a thickness of 0.5 μm was formed on the aluminum surface of an aluminum-deposited polyethylene terephthalate film. On this undercoat layer, a dispersion similar to the disazo pigment dispersion used in Example 2 was applied with a Meyer bar, and dried to form a 0.2 μm-thick charge generation layer. Next, 5 g of a styryl compound represented by the following formula:

[0097]

[Outside 36] And polycarbonate (weight average molecular weight 55,000) 5
g was dissolved in 40 g of tetrahydrofuran, and the solution was coated on the charge generation layer and dried to form a film having a thickness of 20 μm.
m of the charge transport layer was formed.

The charging characteristics and durability characteristics of the produced electrophotographic photosensitive member were evaluated in the same manner as in Examples 1 and 19.
The results are shown below.

V ₀ : −700 V, E _1/2 : 0.85 lux · sec ΔV _D : +5 V, ΔV _L : +5 V

Example 32 A subbing layer of polyvinyl alcohol having a thickness of 0.5 μm was formed on the aluminum surface of an aluminum-deposited polyethylene terephthalate film. A dispersion similar to the dispersion of the disazo pigment used in Example 5 was applied on the undercoating layer with a Meyer bar, and dried to form a charge generation layer having a thickness of 0.2 μm. Next, 5 g of a triarylamine compound represented by the following formula,

[0101]

[Outside 37] And polycarbonate (weight average molecular weight 55,000) 5
g in 40 g of tetrahydrofuran is applied on the charge generation layer and dried to form a film having a thickness of 20 g.
A μm charge transport layer was formed.

The charging characteristics and durability characteristics of the produced electrophotographic photosensitive member were evaluated in the same manner as in Examples 1 and 19.
The results are shown below.

V ₀ : −700 V, E _1/2 : 0.83 lux · sec ΔV _D : 0 V, ΔV _L : +5 V

Example 33 An electrophotographic photosensitive member was prepared in the same manner as in Example 8, except that the charge generation layer and the charge transport layer in the electrophotographic photosensitive member prepared in Example 8 were formed in the reverse order. Evaluation was performed in the same manner as in Example 1. However, the polarity of charging was positive. The results are shown below.

V _O : +700 V, E _1/2 : 1.53 lux · sec

Example 34 A charge generation layer was formed in the same manner as in Example 14. 2,
A solution prepared by dissolving 5 g of 4,7-trinitro-9-fluorenone and 5 g of polycarbonate (weight average molecular weight 30,000) in 50 g of tetrahydrofuran is applied to the above-mentioned charge generating layer with a Meyer bar, and dried to form a film having a thickness of 18 μm. A charge transport layer was formed.

The produced electrophotographic photosensitive member was evaluated in the same manner as in Example 1. However, the polarity of charging was positive. The results are shown below.

V _O : +695 V, E _1/2 : 1.72 lux · sec

Example 35 0.5 g of Disazo Pigment Example 58 was added to cyclohexanone 9.
In addition to 5 g, the mixture was dispersed for 5 hours using a paint shaker. To this dispersion was added a solution in which 5 g of the charge transporting substance used in Example 1 and 5 g of polycarbonate (weight average molecular weight 70,000) were dissolved in 40 g of tetrahydrofuran, and the mixture was shaken for 1 hour. The resulting solution was applied to an aluminum substrate with a Meyer bar and dried to form a film having a thickness of 20 mm.
A photosensitive layer having a thickness of μm was formed. The produced electrophotographic photosensitive member was evaluated in the same manner as in Example 1. However, the polarity of charging was positive. The results are shown below.

V _O : +700 V, E _1/2 : 1.65 lux · sec

[0111]

As described above, according to the present invention, an electrophotographic photoreceptor having high sensitivity and having excellent potential characteristics stably even when used repeatedly, and a process cartridge having the electrophotographic photoreceptor And an electrophotographic apparatus.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus having an electrophotographic photosensitive member of the present invention.

FIG. 2 is a diagram illustrating an example of a block diagram of a facsimile having the electrophotographic photosensitive member of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor of the present invention 1a shaft 2 Charging means 3 Exposure unit 4 Developing means 5 Transfer means 6 Cleaning means 7 Pre-exposure means 8 Image fixing means L Optical image exposure P Transfer material 10 Image reading unit 11 Controller 12 Receiving circuit 13 Transmission circuit 14 Telephone 15 Line 16 Image memory 17 CPU 18 Printer controller 19 Printer

Claims (10)

(57) [Claims] 1. An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer contains a disazo pigment having a 1,2-benzofluorenone structure as a central skeleton. body. 2. The disazo pigment of the following formula (1): (Wherein, A ₁ and A ₂ are the same or different and represent a coupler residue having a phenolic hydroxyl group, and R _{1 to} R ₄ are the same or different and represent a hydrogen atom, a halogen atom, an alkyl group and an alkoxy group. The electrophotographic photoreceptor according to claim 1, wherein at least one selected group is represented, and m and n represent 1, 2 or 3. 3. The electrophotographic photosensitive member according to claim 2, wherein said R _{1 to} R ₄ are hydrogen atoms. 4. The method according to claim 1, wherein A ₁ and A ₂ are the following formulas (2) to (7). (In the formula, X represents a residue necessary for forming a polycyclic aromatic ring or a heterocyclic ring by condensing with a benzene ring, and R ₅ and R ₆ are the same or different and are each a hydrogen atom, an alkyl group, an aryl group. , An aralkyl group, a heterocyclic group and a residue forming a cyclic amino group by bonding to each other, Z represents an oxygen atom or a sulfur atom, and p represents 0 or 1.) (In the formula, X represents a residue necessary for forming a polycyclic aromatic ring or a heterocyclic ring by condensing with a benzene ring, and R ₇ and R ₈ are the same or different and represent a hydrogen atom, an alkyl group, an aryl group. , An aralkyl group, a heterocyclic group, and a residue which forms a cyclic amino group by bonding to each other.) (Wherein, X represents a residue necessary for forming a polycyclic aromatic ring or a heterocyclic ring by condensing with a benzene ring, and R ₉ represents a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, and a heterocyclic group. And Z represents an oxygen atom or a sulfur atom.) (In the formula, X represents a residue necessary for forming a polycyclic aromatic ring or a heterocyclic ring by condensing with a benzene ring, and R ₁₀ and R ₁₁ are the same or different and are a hydrogen atom, an alkyl group, an aryl group. , An aralkyl group and a heterocyclic group.) (In the formula, R ₁₂ represents an alkyl group, an aryl group, an aralkyl group, and a heterocyclic group.) 3. The electrophotographic photoreceptor according to claim 1, wherein Y is a coupler residue represented by at least one formula selected from the group consisting of: an arylene group or a divalent heterocyclic group. 5. The method according to claim 1, wherein A ₁ and A ₂ are represented by formulas (2) to (5).
The electrophotographic photoreceptor according to claim 4, which is represented by at least one formula selected from the group consisting of: wherein X is a coupler residue condensed with a benzene ring to form a benzocarbazole ring. 6. The electrophotographic photoreceptor has a charge generation layer containing the disazo pigment as a charge generation substance on a conductive support, and has a charge transport layer on the charge generation layer. The electrophotographic photosensitive member according to the above. 7. A process cartridge which integrally supports an electrophotographic photosensitive member and at least one means selected from the group consisting of a charging means, a developing means and a cleaning means and is detachable from an electrophotographic apparatus main body. A process cartridge wherein the photosensitive member is an electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer contains a disazo pigment having a 1,2-benzofluorenone structure as a central skeleton. 8. The disazo pigment according to the following formula (1): (Wherein, A ₁ and A ₂ are the same or different and represent a coupler residue having a phenolic hydroxyl group, and R _{1 to} R ₄ are the same or different and represent a hydrogen atom, a halogen atom, an alkyl group and an alkoxy group. The process cartridge according to claim 7, wherein at least one selected group is represented, and m and n represent 1, 2, or 3.). 9. An electrophotographic apparatus having an electrophotographic photosensitive member, a charging unit, an image exposing unit, a developing unit, and a transfer unit, wherein the electrophotographic photosensitive member has a photosensitive layer on a conductive support. An electrophotographic apparatus, wherein the photosensitive layer contains a disazo pigment having a 1,2-benzofluorenone structure as a central skeleton. 10. The disazo pigment according to the following formula (1): (Wherein, A ₁ and A ₂ are the same or different and represent a coupler residue having a phenolic hydroxyl group, and R _{1 to} R ₄ are the same or different and represent a hydrogen atom, a halogen atom, an alkyl group and an alkoxy group. The electrophotographic apparatus according to claim 9, wherein at least one selected group is represented, and m and n represent 1, 2 or 3.).