JPH04355768A - Electrophotographic sensitive body, and electrophotographic device and facsimile both using same - Google Patents

Abstract

PURPOSE:To obtain superior high sensitivity characteristics and stable potential characteristics at the time of repeated uses by forming a photosensitive layer containing a specified disazo pigment on a conductive substrate. CONSTITUTION:The photosensitive layer formed on the conductive substrate contains the disazo pigment represented by formula I in which each of Ar1 and Ar2 is, same on independently, a divalent aromatic group or an aromatic heterocyclic group; n is 1 or 2; A1 is a coupler residue of formula II; A2 is a coupler residue of formula III; each of R1-R4 is H, optionally substituted alkyl, aryl, or an aromatic heterocyclic group; and m is 1 or 2.

Description

[Detailed description of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor having a photosensitive layer containing a disazo pigment having a specific structure, an electrophotographic apparatus and a facsimile equipped with the electrophotographic photoreceptor.

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, electrophotographic photoreceptors made of organic photoconductive substances include photoconductive polymers typified by poly-N-vinylcarbazole and 2,5-bis(p-diethylaminophenyl)-1,3,4- Oxadiazo
There are known methods that use low-molecular organic photoconductive substances such as fluorophores, and also those that combine such organic photoconductive substances with various dyes and pigments. Electrophotographic photoreceptors using organic photoconductive substances have good film-forming properties and can be produced by coating, so they have the advantage of providing extremely highly productive and inexpensive photoreceptors. Furthermore, it has the advantage that color sensitivity can be freely controlled by selecting the dyes and pigments used, and a wide range of studies have been conducted to date. Particularly recently, a functionally separated photoreceptor has been developed in which a charge generation layer containing an organic photoconductive dye or pigment is laminated with a charge transport layer containing the aforementioned photoconductive polymer or low-molecular organic photoconductive substance. As a result, significant improvements have been made in the sensitivity and durability, which were considered to be shortcomings of conventional organic electrophotographic photoreceptors.

[0003]Azo pigments exhibit excellent photoconductivity, and compounds with various properties can be obtained relatively easily by combining the azo component and the coupler component, so many compounds have been developed to date. Proposed. However, electrophotographic photoreceptors using conventional disazo pigments are not necessarily satisfactory in terms of sensitivity and potential stability during repeated use, and only a few materials have been put into practical use. .

0004

SUMMARY OF THE INVENTION The objects of the present invention are to provide a novel photoconductive material, an electrophotographic photoreceptor having excellent high sensitivity characteristics and stable potential characteristics during repeated use; An object of the present invention is to provide an electrophotographic apparatus and a facsimile equipped with the electrophotographic photoreceptor.

[0005]

[Means for Solving the Problems] The present invention provides an electrophotographic photoreceptor having a photosensitive layer on a conductive support, characterized in that the photosensitive layer contains a disazo pigment represented by the following general formula (1). Consists of an electrophotographic photoreceptor. General formula (1)

embedded image In the formula, Ar1 and Ar2 are the same or different and represent a divalent carbocyclic aromatic group or a heterocyclic aromatic group which may have substituents, and n is an integer of 1 or 2. Representation, A
1 represents a coupler residue represented by the following general formula (2), and A
2 represents a residue group selected from the group consisting of coupler residue groups represented by the following general formulas (3) to (8). General formula (2)

[Chemical formula 10] General formula (3)

[Chemical formula 11] General formula (4)

[Chemical formula 12] General formula (5)

[Chemical formula 13] General formula (6)

[Chemical formula 14] General formula (7)

[Chemical formula 15] General formula (8)

embedded image In the formula, X1 to X5 represent a residue group necessary to form a polycyclic aromatic ring or a heterocycle by condensing with a benzene ring, and Z1 to
Z3 represents an oxygen atom or a sulfur atom, and R1 to R10
represents a hydrogen atom, an alkyl group which may have a substituent, a carbocyclic aromatic group or a heterocyclic aromatic group, and R
1 and R2, R3 and R4, R7 and R8 may be bonded to each other to form a ring with a nitrogen atom, R9 and R10 may be bonded to each other to form a ring with a carbon atom, and m is 1.
or represents an integer of 2, p represents an integer of 0, 1 or 2, and Y in general formula (5) may have a substituent 2
Represents a heterocyclic group containing a valent aromatic hydrocarbon or a nitrogen atom in the ring.

Specifically, in Ar1 and Ar2,
Examples of the divalent carbocyclic aromatic group or heterocyclic aromatic group include m-phenylene, p-phenylene, 1,8-naphthylene, 1,5-naphthylene, 2,5-pyridinediyl, 2
, 5-thiophenediyl and the like, X1 to X
In 5, the polycyclic aromatic ring or heterocycle includes a naphthalene ring, anthracene ring, carbazole ring, benzcarbazole ring, dibenzofuran ring, etc.
In No. 10, examples of the alkyl group include groups such as methyl, ethyl, and propyl, examples of the carbocyclic aromatic group include groups such as phenyl, naphthyl, anthryl, benzyl, and phenethyl, and examples of the heterocyclic aromatic group include groups such as phenyl, naphthyl, anthryl, benzyl, and phenethyl. Examples of groups include pyridyl, thionyl, thiazolyl, carbazolyl, benzimidazolyl, and benzothiazolyl, and the rings formed with the nitrogen atom include pyrrole, pyrroline,
Examples include pyridine, indole, imidazole, pyrazole, pyrazoline, oxazine, and phenoxazine. Examples of rings formed with carbon atoms include fluorene, anthraquinone, xanthone, and 1-indanone. Substituents for these groups include alkyl groups such as methyl, ethyl, and propyl, halogen atoms such as fluorine, chlorine, bromine, and iodine, acyl groups such as acetyl and benzyl, and alkylamino such as dimethylamino and diethylamino. group, phenylcarbamoyl group, nitro group, cyano group, haloalkyl group such as trifluoromethyl. In Y, the divalent aromatic hydrocarbon group which may have a substituent or the divalent heterocyclic group containing a nitrogen atom in the ring includes o-phenylene, o-naphthylene, perinaphthylene, 1,2-
Divalent groups such as anthrylene, 3,4-pyrazoldiyl, 2,3-pyridinediyl, 4,5-pyridinediyl, 6,7-indazoldiyl, and 6,7-quinolinediyl are mentioned, and the substituents include is a halogen atom such as fluorine, chlorine, iodine, or bromine, an alkyl group such as methyl, ethyl, or propyl, an alkoxy group such as methoxy or ethoxy, an alkylamino group such as dimethylamino or diethylamino, a phenylcarbamoyl group, a nitro group, or a cyano group. and haloalkyl groups such as trifluoromethyl.

It should be noted that general formulas (2), (3), (6) to (
In 8), when X1 to X5 are coupler residue groups that combine with a benzene ring to form a benzcarbazole ring, the pigment has an absorption range that extends to near the near-infrared region, so it is suitable for semiconductor lasers. It is also suitable as a charge generating material for -.

The present invention also provides an electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer has at least two layers: a charge generation layer containing a disazo pigment represented by the general formula (1), and a charge transport layer. Ru.

The present invention also comprises an electrophotographic apparatus equipped with the electrophotographic photoreceptor of the present invention.

The present invention also comprises an electrophotographic apparatus equipped with the electrophotographic photoreceptor of the present invention, and a facsimile machine having a receiving means for receiving image information from a remote terminal.

Next, typical examples of the disazo pigment represented by the general formula (1) of the present invention are shown in Tables 1 to 8, but the disazo pigment used in the present invention is not limited to these. The specific structure of the exemplified pigment will be expressed by describing only the parts that change in the basic form.

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

[Table 7]

[Table 8]

The disazo pigment represented by the general formula (1) can be obtained by tetrazotizing the corresponding diamine by a conventional method and coupling it with a coupler in an aqueous system in the presence of an alkali, or by converting the tetrazonium salt into a borofluoride salt or a zinc chloride double salt. After converting the coupler into
It can be easily synthesized by coupling with

When synthesizing a disazo pigment in which A1 and A2 in the general formula (1) are different couplers, first 1 mol of one of the couplers is coupled to 1 mol of the above-mentioned tetrazonium salt, and then It can be synthesized by coupling 1 mole of the other coupler, or one of the amino groups of the diamine is protected with an acetyl group, etc., this is diazotized, one coupler is coupled, and then the protecting group is It can be synthesized by hydrolyzing with hydrochloric acid or the like, diazotizing this again, and coupling with the other coupler.

In the present invention, in view of ease of synthesis, it is preferable that A1 and A2 are the same coupler residue.

Synthesis Example (Synthesis of Exemplary Pigment (1)) In a 300 ml beaker, 150 ml of water and 2 ml of concentrated hydrochloric acid were added.
0ml (0.23mol)

Add 6.7 g (0.032 mol) of [Chemical 17] and cool to 0°C.
A solution prepared by dissolving 4.6 g (0.067 mol) of sodium nitrite in 10 ml of water was added dropwise over 10 minutes while maintaining the temperature of the solution at 5°C. After stirring for 15 minutes, carbon filtration was performed, and a solution prepared by dissolving 10.5 g (0.096 mol) of sodium borofluoride in 90 ml of water was added dropwise to this solution while stirring to remove the precipitated borofluoride salt. It was collected by filtration, washed with cold water, washed with acetonitrile, and dried under reduced pressure at room temperature. Yield9.
48g, yield 73% Next, add DMF5 to a 1 liter beaker.
Add 00ml,

After dissolving 12.9 g (0.042 mol) of [Chemical formula 18] and cooling the liquid temperature to 5°C, 8.1 g (0.02 mol) of the previously obtained borofluoride salt was dissolved.
0 mol) and then 5.1 g (
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: 14.3 g, yield: 86%.

The electrophotographic photoreceptor of the present invention has a photosensitive layer containing a disazo pigment represented by the general formula (1) on a conductive support. The form of the photosensitive layer may be any known form; however, a photosensitive layer containing a disazo pigment represented by general formula (1) is used as a charge generation layer, and a charge transport layer containing a charge transporting substance is added thereto. Laminated functionally separated photosensitive layers are particularly preferred.

The charge generation layer can be formed by coating a coating solution in which the above-mentioned disazo pigment is dispersed together with a binder resin in a suitable solvent on a conductive support by a known method, and the film is For example, the thickness is 5 μm or less,
Preferably, the thickness is preferably 0.1 to 1 μm. The binder resin used in this case is selected from a wide range of insulating resins and organic photoconductive polymers.
Preferred are polyvinyl butyral, polyvinyl benzal, polyarylate, polycarbonate, polyester, phenoxy resin, cellulose resin, acrylic resin, polyurethane, etc., which may have a substituent, and the substituent is alkyl such as methyl, ethyl, propyl, etc. groups, halogen atoms such as fluorine, chlorine, bromine, and iodine atoms, acyl groups such as acetyl and benzyl, alkylamino groups such as dimethylamino and diethylamino, phenylcarbamoyl groups, nitro groups, cyano groups, trifluoromethyl, etc. Examples include groups such as a haloalkyl group. The content of the binder resin in the charge generation layer is 80%.
It is not more than 40% by weight, preferably not more than 40% by weight. The solvent used is preferably selected from those that dissolve the resin described above but do not dissolve the charge transport layer or 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 laminated above or below the charge generation layer and has the function of receiving charge carriers from the charge generation layer in the presence of an electric field and transporting them. The charge transport layer is formed by dissolving a charge transport substance in a solvent together with an appropriate binder resin as necessary and coating the layer, and the film thickness is generally 5 to 40 μm, but 15 to 30 μm.
is preferred. Charge transporting substances include electron transporting substances and hole transporting substances, and examples of electron transporting substances include 2,4
Examples include electron-withdrawing substances such as , 7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, chloranil, and tetracyanoquinodimethane, and polymerized versions of these electron-withdrawing substances. Hole-transporting substances include polycyclic aromatic compounds such as pyrene and anthracene, carbazole-based, indole-based, imidazole-based, oxazole-based, thiazole-based, oxadiazole-based, and pyrazole-based substances. , heterocyclic compounds such as pyrazoline, thiadiazole, and triazole compounds, p-diethylaminobenzaldehyde N,N-diphenylhydrazone,
N,N-diphenylhydrazino-3-methylidene-9-
Hydrazone compounds such as ethylcarbazole, α-phenyl-4'-N,N-diphenylaminostilbene,
5-[4-(di-p-tolylamino)benzylidene]-
A styryl compound such as 5H-dibenzo[a,d]cycloheptene, a benzidine compound, a triarylmethane compound, triphenylamine, or a polymer having a group consisting of these compounds in its main chain or side chain (for example, poly- N-vinylcarbazole, polyvinylanthracene, etc.). In addition to these organic charge transport materials, selenium, selenium-tellurium, amorphous silicon,
Inorganic materials such as cadmium sulfide can also be used. Further, these charge transport materials can be used alone or in combination of two or more. When the charge transport material does not have film-forming properties, a suitable binder can be used. Specifically, acrylic resin, polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer, polyacrylamide,
Examples include insulating resins such as polyamide and chlorinated rubber, and organic photoconductive polymers such as polyN-vinylcarbazole and polyvinylanthracene.

Examples of the conductive support on which the photosensitive layer is formed include aluminum, aluminum alloy, copper, zinc,
Stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold, and platinum are used. In addition, plastics (e.g., polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, etc.) or conductive particles (e.g., carbon black, silver particles, etc.) coated with these metals or alloys by vacuum deposition are coated with a suitable binder resin. In addition, a support coated on a plastic or metal substrate, or a support made of plastic or paper impregnated with conductive particles can be used.

[0020] An undercoat layer having barrier and adhesive functions may also 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, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, aluminum oxide, or the like. The thickness of the undercoat layer is suitably 5 μm or less, preferably 0.1 to 3 μm.

Another specific example of the present invention is an electrophotographic photoreceptor containing the above-mentioned disazo pigment and charge transport material in the same layer. In this case, a charge transfer complex consisting of poly N-vinylcarbazole and trinitrofluorenone can also be used as the charge transport substance. The electrophotographic photoreceptor of this example can be formed by coating and drying a solution in which the above-mentioned disazo pigment and charge transfer complex are dispersed in a suitable resin solution. In any electrophotographic photoreceptor, the crystal form of the disazo pigment represented by the general formula (1) may be amorphous or crystalline, and if necessary, the disazo pigment represented by the general formula (1) may have a crystalline form. It is also possible to use a combination of two or more types of pigments or a combination with a known charge generating substance.

The electrophotographic photoreceptor of the present invention can be used not only for electrophotographic copying machines, but also for laser beam printers, C
RT printer, LED printer, LCD printer,
It can also be widely used in electrophotographic applications such as laser engraving and facsimile.

Next, an electrophotographic apparatus and a facsimile equipped with the electrophotographic photoreceptor of the present invention will be explained. Figure 1
The schematic structure of a general transfer type electrophotographic apparatus using the drum-type photoreceptor of the present invention is shown in FIG. In the figure, reference numeral 1 denotes a drum-type photoreceptor as an image carrier, which is rotated at a predetermined circumferential speed in the direction of the arrow around an axis 1a. During the rotation process, the photoreceptor 1 is uniformly charged to a predetermined positive or negative potential on its circumferential surface by the charging means 2, and then subjected to light image exposure L (slit exposure/ laser
beam scanning exposure, etc.). As a result, electrostatic latent images corresponding to the exposed images are sequentially formed on the circumferential surface of the photoreceptor. The electrostatic latent image is then developed with toner by a developing means 4, and the toner-developed image is transferred by a transfer means 5 from a paper feed section (not shown) between the photoreceptor 1 and the transfer means 5, when the photoreceptor 1 is rotated. The images are sequentially transferred onto the surface of the transfer material P that is fed in synchronization with the image data. The transfer material P that has undergone the image transfer is separated from the photoreceptor surface and introduced into the image fixing means 8, where the image is fixed and a copy is formed.
) is printed out outside the aircraft. After the image has been transferred, the surface of the photoreceptor 1 is cleaned by a cleaning means 6 to remove residual toner after transfer, and is subjected to a charge removal process by a pre-exposure means 7 and used repeatedly for image formation. As the uniform charging means 2 for the photoreceptor 1, a corona charging device is generally widely used. Further, as for the transfer device 5, a corona transfer means is generally widely used. An electrophotographic apparatus is constructed by combining a plurality of components such as the above-mentioned photoreceptor, developing means, and cleaning means into an apparatus unit, and this unit is detachably attached to the main body of the apparatus. It may be configured. For example, the photoreceptor 1 and the cleaning means 6
They may be integrated into one device unit, and configured to be detachable using guide means such as rails on the device body. At this time, the above-mentioned device unit may include 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 can be carried out by using reflected light or transmitted light from the original, or by reading the original and converting it into a signal, and then using a laser according to this signal. This is performed by scanning a beam, driving a light emitting diode array, or driving a liquid crystal shutter array. Further, when used as a facsimile printer, the optical image exposure L is exposure for printing received data.

FIG. 2 is a block diagram showing an example of this case. A controller 11 controls an image reading section 10 and a printer 19. The entire controller 11 is controlled by a CPU 17. The read data from the image reading section is transmitted to the other party's station through the transmitting 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. A printer controller 18 controls a printer 19. 14 is a telephone. Line 15
After the image received from the remote terminal (image information from a remote terminal connected via a line) is demodulated by the receiving circuit 12, the CPU 17 performs signal processing on the image information and sequentially stores it in the image memory 16. . When at least one page of images is stored in the memory 16, the image of that page is stored. The CPU 17 reads one page of image information from the memory 16 and sends the signaled one page of image information to the printer controller 18. printer control
When the printer 18 receives one page of image information from the CPU 17, it controls the printer 19 to record the image information of that page. Note that the CPU 17 receives the next page while the printer 19 is recording. As described above, images are received and recorded.

[0025]

[Example] Examples 1 to 11 5 g of methoxymethylated nylon (number average molecular weight 32,000) and 10 g of alcohol-soluble copolymerized nylon (number average molecular weight 29,000) were placed on an aluminum support with methanol. Apply the solution dissolved in 95g with a Mayer bar, and the film thickness after drying is 1.
A subbing layer of μm was formed.

Next, 5 g of pigment 1 was added to 95 g of cyclohexanone.
The mixture was added to a solution prepared by dissolving 2 g of polyvinyl benzal (benzalization degree of 75% or more) in g and dispersed in a sand mill for 20 hours. This dispersion was applied onto the previously formed undercoat layer using a Mayer bar so that the film thickness after drying was 0.2 μm, and dried to form a charge generation layer.

Next, styryl compound 5 shown by the following structural formula
g and

[Chemical formula 19] Polymethyl methacrylate (number average molecular weight 100,000) 5 g
was dissolved in 40 g of chlorobenzene and spread on a Meyer bar so that the dry film thickness was 20 μm.
The electrophotographic photoreceptor of Example 1 was prepared by coating and drying to form a charge transport layer.

Example 2 Using another pigment in place of Pigment 1
Electrophotographic photoreceptors corresponding to Examples 1 to 11 were prepared in exactly the same manner.

The produced electrophotographic photoreceptor was manufactured by Kawaguchi Electric Co., Ltd.
The paper was negatively charged with a corona discharge of -5 KV using an electrostatic copying paper tester Model SP-428 manufactured by Manufacturer Co., Ltd. After being held in a dark place for 1 second, it was exposed to light using a halogen lamp at an illuminance of 10 lux to evaluate the charging characteristics. . As for the charging characteristics, the surface potential (V0) and the exposure amount (E1/2) required for the surface potential to attenuate to 1/2 after being left in a dark place were measured. Show the results. Example 1 Pigment 1 V0: -680V, E1/2: 1.35
Lux/Second Example 2 Pigment 2 V0: -669V, E1/2: 1.59
Lux/Second Example 3 Pigment 3 V0: -680V, E1/2: 1.
61 lux/sec Example 4 Pigment 4 V0: -712V, E1/2: 2.01
Lux/Second Example 5 Pigment 5 V0: -710V, E1/2: 1.45
Lux/sec Example 6 Pigment 17 V0: -700V, E1/2: 1.35 Lux/sec Example 7 Pigment 18 V0: -705V, E1/2: 2.13 Lux/sec Example 8 Pigment 19 V0: -705V, E1/2: 1.63 lux/sec Example 9 Pigment 24 V0: -712V, E1/2: 1.78 lux/sec Example 10 Pigment 25 V0: -725V, E1/2: 1.90 Lux/sec Example 11 Pigment 26 V0: -710V, E1/2: 1.20 lux/sec

Comparative Examples 1 and 2

[Table 9] Comparative pigment 1 shown in Table 9 is the disazo pigment used in Example 1.
An electrophotographic photoreceptor was prepared in exactly the same manner as in Example 1, except that Example 1 and Example 2 were replaced, and the charging characteristics were evaluated in the same manner. Show the results. Comparative Example 1 Comparative Pigment 1 V0: -650V, E1/2: 9.85
Lux/second comparative example 2 Comparative pigment 2 V0: -632V, E1/2: 7.66
Lux/sec This result shows that the electrophotographic photoreceptor of the present invention has sufficient charging ability and excellent sensitivity.

Examples 12 to 15 The electrophotographic photoreceptor prepared in Example 6 was equipped with a -6.5 KV corona charger, an exposure optical system, a developer, a transfer charger, a static elimination exposure optical system, and a cleaner. It was attached to the cylinder of an electrophotographic copying machine. The initial dark potential VD and bright potential VL are set to around -700V and -200V, respectively.
The amount of variation in dark potential (ΔVD) after repeated use 5,000 times
) and the amount of variation in bright area potential (ΔVL) were measured. Example 7
The electrophotographic photoreceptors prepared in Examples 8 and 9 were also evaluated in the same manner. Show the results. Note that a negative sign in the amount of change in potential represents a decrease in the absolute value of the potential, and a positive sign represents an increase in the absolute value of the potential. Example 12 ΔVD: +5V, ΔVL:
0V Example 13 ΔVD: 0V, ΔVL
:+5V Example 14 ΔVD: 0V, Δ
VL: 0V Example 15 ΔVD: 0
V, ΔVL: +5V

Comparative Example 3 Regarding the electrophotographic photoreceptor prepared in Comparative Example 1, Example 1
Potential fluctuations during repeated use were measured by the same method as in 2. Show the results. ΔVD: -45V, ΔVL: +5
5V From the above results, it can be seen that the electrophotographic photoreceptor of the present invention has little potential fluctuation during repeated use.

Example 16 A subbing layer of polyvinyl alcohol having a thickness of 0.5 μm was formed on the aluminum surface of an aluminum vapor-deposited polyethylene terephthalate film. On top of this, 5 g of Pigment 1 was added to a solution prepared by dissolving 2 g of butyral resin (butyralization degree 63 mol%) in 95 g of cyclohexanone, and a dispersion prepared in the same manner as in Example 1 was applied and dried to form a film. A charge generation layer having a thickness of 0.2 μm was formed.

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

embedded image A solution obtained by dissolving 5 g of polycarbonate (weight average molecular weight: 55,000) in 40 g of tetrahydrofuran was applied onto the charge generation layer and dried to form a charge transport layer with a thickness of 20 μm. The charging characteristics and durability characteristics of the produced electrophotographic photoreceptor were measured in the same manner as in Examples 1 and 12. Show the results. V0: -700V, E1/2: 1.48 lux・secΔ
VD: +5V, ΔVL: +5V

Example 17 A subbing layer of polyvinyl alcohol having a thickness of 0.5 μm was formed on the aluminum surface of an aluminum vapor-deposited polyethylene terephthalate film. On top of this, 5 g of Pigment 17 was added to a solution prepared by dissolving 2 g of poly-p-fluorovinylbenzal (benzalization degree of 75% or more) in 95 g of tetrahydrofuran, and a dispersion prepared in the same manner as in Example 1 was applied. It was dried to form a charge generation layer with a thickness of 0.2 μm.

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

embedded image A solution obtained by dissolving 5 g of polycarbonate (weight average molecular weight: 55,000) in 40 g of chlorobenzene was applied onto the charge generation layer and dried to form a charge transport layer with a thickness of 20 μm. The charging characteristics and durability characteristics of the produced electrophotographic photoreceptor were measured in the same manner as in Examples 1 and 12. Show the results. V0: -706V, E1/2: 1.15 lux・secΔ
VD: -5V, ΔVL: +5V

Example 18 An electrophotographic photoreceptor was prepared by applying the charge generation layer and charge transport layer of the electrophotographic photoreceptor prepared in Example 6 in the reverse order, and the charging characteristics were determined by the same method as in Example 1. was evaluated. ,
However, the charging was positive. Show the results. V0: -673V, E1/2: 1.95 lux・sec

[
Example 19 4.5 g of 2,4,7-trinitro-9-fluorenone and poly-4,4'-dioxydiphenyl-2,2-propane carbonate were placed on the charge generating layer prepared in Example 6. A solution prepared by dissolving 5 g of carbonate (number average molecular weight: 300,000) in 50 g of tetrahydrofuran was applied with a Meyer bar, and the film thickness after drying was 1.
A charge transport layer of 8 μm was formed. The charging characteristics of the produced electrophotographic photoreceptor were evaluated in the same manner as in Example 1. However, the charging was positive. V0: +655V, E1/2: 3.92 lux/sec

[
Example 20 0.5 g of Pigment 17 was dispersed with 9.5 g of cyclohexanone in a paint shaker for 5 hours. Example 1 here
5 g of the same charge transport material used in and polycarbonate 5
A solution prepared by dissolving 1.0 g of 1.0 g in 40 g of tetrahydrofuran was added thereto, and the mixture was further stirred for 1 hour. The coating solution thus prepared was applied onto an aluminum support using a Mayer bar and dried until the film thickness was 20 mm.
A photosensitive layer of μm was formed. The charging characteristics of the electrophotographic photoreceptor thus prepared were evaluated in the same manner as in Example 1. The charging was positive. V0: +635V, E1/2: 2.52 lux/sec

[
0040

Effects of the Invention In the electrophotographic photoreceptor of the present invention, by using a disazo pigment with a specific structure in the photosensitive layer, the generation efficiency and/or injection efficiency of charge carriers placed inside the photosensitive layer is improved. , the electrophotographic photoreceptor has the remarkable effect of providing excellent characteristics in terms of sensitivity and potential stability during repeated use, and the same remarkable effect can also be achieved in electrophotographic devices and facsimile machines equipped with the electrophotographic photoreceptor.

[Brief explanation of drawings]

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

FIG. 2 is a block diagram of a facsimile machine using an electrophotographic device as a printer.

[Explanation of symbols]

1 Drum type photoreceptor as an image carrier (electrophotographic photoreceptor of the present invention) 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 Photoimage exposure P Transfer material 10 that has undergone image transfer Image reading section 11 Controller 12 Receiving circuit 13 Transmitting circuit 14 Telephone 15 Line 16 Image memory 17 CPU 18 Printer controller 19 Printer

Claims (5)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer contains a disazo pigment represented by the following general formula (1). General formula (1) [Formula 1] In the formula, Ar1 and Ar2 are the same or different and represent a divalent carbocyclic aromatic group or a heterocyclic aromatic group which may have substituents, and n is 1 or represents an integer of 2, A
1 represents a coupler residue represented by the following general formula (2), and A
2 represents a residue selected from the group consisting of coupler residues represented by the following general formulas (3) to (8). General formula (2) [Chemical formula 2] General formula (3) [Chemical formula 3] General formula (4) [Chemical formula 4] General formula (5) [Chemical formula 5] General formula (6) [Chemical formula 6] General formula (7) [Chemical Formula 7] General Formula (8) [Chemical Formula 8] In the formula, X1 to X5 represent a residue group necessary to form a polycyclic aromatic ring or a heterocycle by condensing with a benzene ring, and Z1 to
Z3 represents an oxygen atom or a sulfur atom, and R1 to R10
represents a hydrogen atom, an alkyl group which may have a substituent, a carbocyclic aromatic group or a heterocyclic aromatic group, and R
1 and R2, R3 and R4, R7 and R8 may be bonded to each other to form a ring with a nitrogen atom, R9 and R10 may be bonded to each other to form a ring with a carbon atom, and m is 1.
or represents an integer of 2, p represents an integer of 0, 1 or 2, and Y in general formula (5) may have a substituent 2
Represents a heterocyclic group containing a valent aromatic hydrocarbon or a nitrogen atom in the ring. 2. The electrophotographic photoreceptor according to claim 1, wherein A2 is a coupler residue represented by general formula (3), and p is an integer of 1 or 2. 3. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer has at least two layers: a charge generation layer containing a disazo pigment represented by formula (1) and a charge transport layer. 4. An electrophotographic apparatus comprising the electrophotographic photoreceptor according to claim 1. 5. A facsimile machine comprising an electrophotographic apparatus comprising the electrophotographic photoreceptor according to claim 1 and means for receiving image information from a remote terminal. 0001