JPH0488349A - Electrophotographic sensitive body and apparatus provided with same and facsimile - Google Patents

Abstract

PURPOSE:To obtain practicable high sensitivity characteristics and stable potential characteristics during repeating uses by forming a photosensitive layer containing a specified disazo pigment on a conductive substrate. CONSTITUTION:This photosensitive layer formed on the conductive substrate contains the disazo pigment represented by formula I in which each of Ar1 and Ar2 is independently an optionally substituted aromatic hydrocarbon group or such a heterocyclic group optionally linked through a bonding group; each of A1 and A2 is independently coupler residue having a phenolic hydroxyl group; and (n) is 2, 3, or 4. The photosensitive layer may formed into all the known types, but it is especially preferred to use a photosensitive layer containing the disazo pigment of formula I for an electric charge generating layer and to laminate a charge transfer layer containing a charge transfer material on the charge generating layer to form a functionally separated photosensitive layer, thus permitting sensitive and durability to be enhanced and variance between potentials in the light and in the dark to be reduced during successive image formations by repeating cycles of charging exposure.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to an electrophotographic photoreceptor, an electrophotographic device equipped with the electrophotographic photoreceptor, and a facsimile, and more particularly, to a photoreceptor containing a disazo pigment having a specific structure. The present invention relates to an electrophotographic photoreceptor having a layer, an electrophotographic apparatus equipped with the electrophotographic photoreceptor, and a facsimile.

[Prior Art] Electrophotography, as disclosed in U.S. Pat. No. 2,297,691, involves coating an insulating material in the dark, the electrical resistance of which changes depending on the amount of radiation received during image exposure. A photoconductive material consisting of a support is used.

The basic characteristics required of an electrophotographic photoreceptor using this photoconductive material are (1) ability to be charged to an appropriate potential in a dark place, (2) low charge dissipation in a dark place, ( 3) The ability to quickly dissipate charges by light irradiation.

Conventionally, inorganic electrophotographic photoreceptors having a photosensitive layer mainly composed of an inorganic photoconductive compound such as selenium, zinc oxide, or cadmium sulfide have been widely used as electrophotographic photoreceptors. However, although these satisfy the conditions (1) to (3) above, they do not necessarily satisfy conditions such as thermal stability, moisture resistance, and durability.

For example, when selenium crystallizes, its properties as an electrophotographic photoreceptor deteriorate, making it difficult to manufacture.Also, selenium crystallizes due to heat or exposure to fingernails, deteriorating its performance as a photoreceptor.

Furthermore, cadmium sulfide has problems with moisture resistance and durability, and zinc oxide has problems with smoothness, hardness, and abrasion resistance.

Furthermore, most inorganic electrophotographic photoreceptors have a limited sensitivity wavelength range. For example, selenium is in the blue region and has almost no sensitivity in the red region.

For this reason, various methods have been proposed to extend the photosensitivity to a longer wavelength range, but there are many restrictions on the selection of the sensitive wavelength range.

Even when zinc oxide or cadmium sulfide is used as a photoreceptor, its sensitivity wavelength range is narrow and the addition of various sensitizers is required.

In order to overcome the drawbacks of these inorganic electrophotographic photoreceptors, electrophotographic photoreceptors containing various organic photoconductive compounds as main components have been actively developed in recent years. For example, Tokuko Sho 5
No. 0-10496 and U.S. Pat. No. 3,484,237 disclose poly-N-vinylcarbazole and 2.4.7-
A photoreceptor having a photosensitive layer containing 4-linitrofluorenone-9-one, a poly-N-vinylcarbazole sensitized with a biryllium salt dye (Japanese Patent Publication No. 48-25658
Publication No.) etc.

Although these organic electrophotographic photoreceptors have improved the drawbacks of the inorganic electrophotographic photoreceptors to some extent, they generally have low photosensitivity and are not suitable for repeated use.

In order to overcome the above-mentioned drawbacks, various electrophotographic photoreceptors have been proposed in recent years as organic electrophotographic photoreceptors. A layered electrophotographic photoreceptor consisting of a charge generation layer (layer) and a layer (charge transport layer) mainly composed of a material (charge transport material) that receives and transports charge carriers generated by a charge generation layer is a conventional organic photoreceptor. Compared to electrophotographic photoreceptors, some are in practical use because they generally have higher sensitivity (and can withstand repeated use).

Such organic photoconductive compounds are easier to synthesize than inorganic photoconductive compounds, and the visible light sensitivity can be changed relatively easily by molecular design, making it easy to control color sensitivity. In recent years, various companies have been competing to develop photoconductive compounds, and some have reached the level of practical use in terms of sensitivity and durability. Not a few.

However, at present, they are still inferior to inorganic photoconductive compounds such as amorphous silicone in terms of durability, potential stability during repeated use, and the presence or absence of potential changes due to environmental changes.

[Problems to be Solved by the Invention] The objects of the present invention are to provide a new photoconductive material and to provide an electrophotographic photoreceptor having practical 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.

[Means for Solving the Problems, Effects] The present invention comprises an electrophotographic photoreceptor characterized by having a photosensitive layer containing a disazo pigment represented by the following formula (1) on a conductive support.

-Formula %Formula % (1) In the formula, Ar+ and Ar2 are the same or different and represent an aromatic hydrocarbon group or an aromatic heterocyclic group to which a substituent may be attached via a bonding group. , A, and A2
represent coupler residues having the same or different phenolic hydroxyl groups, and n represents an integer of 2 to 4.

Specifically, Ar+Fi and A r z are aromatic hydrocarbon groups such as benzene, naphthalene, fluorene, phenanthrene, anthracene, and pyrene, which may have substituents, furan, thiophene, pyridine, indole, benzothiazole, and carbazole. , acridone, dibenzothiophene, benzoxazole, benzotriazole, oxadiazole, thiazole and other aromatic heterocyclic groups, and those in which the above aromatic rings are bonded directly or with an aromatic group or a non-aromatic group, such as triphenyl Amine, diphenylamine, N-methyldiphenylamine, biphenyl, terphenyl, binaphthyl, fluorenone, phenanthrene, quinone, anthraquinone, benzanthrone, diphenyloxadiazole, phenylbenzoxazole, diphenylmethane, diphenylsulfone, diphenyl ether, benzophenone, stilbene, distyrylbenzene , tetraphenyl-p-phenylenediamine, tetraphenylbenzidine, and the like. Substituents that these groups may have include fluorine, chlorine,
Halogen atoms such as iodine and bromine, alkyl groups such as methyl, ethyl, propyl, butyl, alkoxy groups such as methoxy and ethoxy, dialkylamino groups such as dimethylamino and diethylamino, hydroxyl groups, nitro groups, cyano groups, heromethyl groups, etc. can be mentioned.

Preferred examples of the coupler residues having a phenolic hydroxyl group represented by A1 and A include residues represented by the following general formulas (2) to (6).

In general formulas (2), (3), and (4), Represents the residues necessary to form an aromatic ring or a heterocycle.

Y in general formula (6) represents a divalent aromatic hydrocarbon group which may have a substituent or a divalent heterocyclic group containing a nitrogen atom in the ring, and specifically, 0-phenylene, 0-Naphthylene, Perinaphthylene, 1゜2-Anthrylene, 3.4-
Pyrazolediyl, 2.3-pyridinediyl, 4.5-
Pyridinediyl, 6.7-indazolediyl, 6.7
- Divalent groups such as chiralediyl are mentioned.

R and Rt in general formulas (2) and (3) represent a hydrogen atom, an alkyl group that may have a substituent, an aryl group, an aralkyl group, or a heterocyclic group, and both R1 and Rt are nitrogen atoms. may be combined with to form a cyclic amino group containing a nitrogen atom in the ring.

R1 in general formula (4) represents a hydrogen atom, an alkyl group that may have a substituent, an aryl group, an aralkyl group, or a heterocyclic group.

R4 in general formula (5) represents a hydrogen atom, an alkyl group that may have a substituent, an aryl group, an aralkyl group, or a heterocyclic group.

Examples of alkyl groups in the above expression include groups such as methyl, ethyl, and propyl; specific examples of aryl groups include groups such as phenyl, naphthyl, and anthryl; examples of aralkyl groups include groups such as pencil and phenethyl; and examples of heterocyclic groups include pyridyl, Groups such as thienyl, carbazolyl, benzimidazolyl, and benzothiazolyl, and cyclic amino groups containing a nitrogen atom in the ring include virol, viroline, pyrrolidine, pyrrolidone, indole, indoline, carbazole, imidazole, pyrazole, pyrazoline, oxazine, and phenoxazine. It will be done.

Substituents include halogen atoms such as fluorine, chlorine, iodine, and bromine; alkyl groups such as methyl, ethyl, and propyl; alkoxy groups such as methoxy and ethoxy; alkylamino groups such as dimethylamino and diethylamino;
Examples include a phenylcarbamoyl group, a nitro group, a cyano group, and a halomethyl group such as trifluoromethyl.

Z in general formula (2) represents an oxygen atom or a sulfur atom,
β is an integer of 0 or 1.

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

Note that - in formula (1), A1. A* is the general formula (2), (
3) or (4), in which X is a Gabler group condensed with a benzene ring to form a benzcarbazole ring, the absorption range of the pigment extends to near the near-infrared region. Therefore, it is also suitable as a charge generating material for semiconductor lasers.

Further, the present invention comprises an electrophotographic apparatus equipped with the electrophotographic photoreceptor of the present invention.

Further, the present invention 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.

Typical specific examples of the disazo pigment represented by the general formula (1) of the present invention are listed below, but the disazo pigment used in the present invention is not limited to these.

Exemplary Pigment (1) Exemplary Pigment (2) Exemplary Pigment (3) ■ A t -N=N-@-C-C combination N=N-A2 Exemplary Pigment (4) Exemplary Pigment (8) Exemplary Pigment (5) Exemplary Pigment Pigment (6) Exemplary Pigment (9) Exemplary Pigment (10) Exemplary Pigment (11) Exemplary Pigment (12) Cg.

Exemplary Pigment (l 3) Exemplary Pigment (17) Exemplary Pigment (18) Exemplary Pigment (19) Exemplary Pigment (14) Exemplary Pigment (15) Exemplary Pigment (16) Exemplary Pigment (20) r Exemplary Pigment (21) Exemplary Pigment ( 22) Exemplary Pigment (23) Exemplary Pigment (24) Exemplary Pigment (25) Exemplary Pigment (26) I2 Exemplary Pigment (30) Exemplary Pigment (3 Exemplary Pigment (32) Exemplary Pigment (27) Exemplary Pigment (28) Exemplary Pigment ( 29) A, -N=N↓Psha N・N-A2 example pigment (33
) Exemplary Pigment (34) Exemplary Pigment (35) Exemplary Pigment (36) Exemplary Pigment (37) Exemplary Pigment (4l) Exemplary Pigment (42) Exemplary Pigment Exemplary Pigment (38) Exemplary Pigment (39) Exemplary Pigment (40) Exemplary Pigment (44) Exemplary pigment (45) Exemplary pigment (46) Exemplary pigment (48) Exemplary pigment (52) Exemplary pigment (53) Exemplary pigment (54) Exemplary pigment (50) Exemplary pigment (51) Exemplary pigment ( 55) Exemplary Pigment (56) Exemplary Pigment (57) Exemplary Pigment (58) Exemplary Pigment (59) Exemplary Pigment (60) Exemplary Pigment (61) Exemplary Pigment (65) Exemplary Pigment (66) Exemplary Pigment (67) Exemplary Pigment ( 62) Exemplary Pigment (63) Exemplary Pigment (64) Exemplary Pigment (68) Exemplary Pigment (69) Exemplary Pigment (70) Exemplary Pigment (71) Exemplary Pigment (74) Exemplary Pigment (72) Exemplary Pigment (75) Exemplary Pigment ( 73) The disazo pigment represented by the general formula (1) can be produced 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 a tetrazonium salt into a borofluoride salt, zinc chloride double salt, etc. After conversion, N, N-
It can be easily synthesized by coupling with a coupler in an organic solvent such as dimethylformamide or dimethyl sulfoxide in the presence of a base such as sodium acetate, triethylamine, or N-methylmorpholine.

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

Synthesis Example (Synthesis of Exemplified Pigment (1)) In a 500 mI2 beaker, 100 mI2 of water and 13.
After adding 24mβ (0,150 mol) and (0,03 mol) and stirring and cooling to 4°C,
A solution prepared by dissolving 4.35 g (0,0630 mol) of sodium nitrite in 13 mβ of water was added dropwise over 5 minutes, then the solution temperature was maintained at 4 to 7°C, stirred for 30 minutes, treated with carbon, and then filtered. . In this solution, 10.5 g of sodium fluoride
(0,096 mol) dissolved in 90 m2 of water was soaked under stirring, and the precipitated borofluoride salt was collected by filtration, washed with cold water, then acetonitrile, and dried under reduced pressure at room temperature.

Yield 10.01g, Yield 92.60% Next, put DMF 500 m I2 into a beaker 12, dissolve it, cool the liquid temperature to 5℃, and add 7.24g of the borofluoride salt obtained earlier (0 ,020 mol) and then 5.1 g (0,050 mol) of triethylamine
It was dripped in 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 13.85 g, yield 80.76% Elemental analysis calculated value (%) Actual value (%) C67,2167,24 H3,533,55 N 9.80 9.78 The electrophotographic photoreceptor of the present invention has a conductive The general formula (
It has a photosensitive layer containing the disazo pigment shown in 1). The form of the photosensitive layer may be any known form, but - a photosensitive layer containing a disazo pigment represented by formula (1) is used as a charge generation layer, and a charge transport layer containing a charge transport substance is added thereto. Laminated functionally separated photosensitive layers are particularly preferred.

The charge generation layer can be formed by coating a coating liquid in which the above-mentioned azo pigment is dispersed together with a binder resin in a suitable solvent on a conductive support by a known method, and the film thickness thereof is, for example, 5 μm. Below, preferably 0.1
A thin film layer of ~Ium is desirable.

The binder resin used in this case is selected from a wide range of insulating resins or organic photoconductive polymers, including polyvinyl butyral, polyvinylbenzal, polyarylate, polycarbonate, polyester, phenoxy resin, cellulose resin, acrylic resin, polyurethane. etc., and the amount used is 8% in terms of content in the charge generation layer.
It is 0% by weight or less, preferably 40% by weight or less.

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, xylene, Examples include aromatics such as chlorobenzene, alcohols such as methanol, ethanol, and 2-propanol, and aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichlorethylene.

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 material in a solvent together with a suitable binder resin as necessary and coating the film, and the film thickness is generally 5 to 40 am.
5 to 30 um is preferable.

Charge-transporting substances include electron-transporting substances and hole-transporting substances. Examples of electron-transporting substances include 2゜4.7-)linitrofluorenone, 2,4,5゜7-titranitrofluorenone, chloranil, Examples include electron-withdrawing substances such as tetracyanoquinodimethane and polymerized materials 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, pyrazole-based pyrazoline-based, thiadiazole-based, triazole-based compounds, etc. heterocyclic compound, p-
Hydrazone-based compounds such as diethylaminobenzaldehyde-N,N-diphenylhydrazone, N,N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, a-phenyl-4°-N,N-diphenylaminostilbene, 5-[ 4-(di-p-tolylamino)benzylidene] -5H-dibenzo[a,dl Styryl compounds such as cycloheptene, benzidine compounds, triarylmethane compounds, triphenylamine, or a group consisting of these compounds in the main chain Alternatively, polymers having side chains (eg, poly-N-vinylcarbazole, polyvinylanthracene, 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 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, insulating resins such as acrylic resin, polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer, polyacrylamide, polyamide, and chlorinated rubber, or organic photoconductive resins such as poly-N-vinylcarbazole and polyvinylanthracene. Polymers and the like can be mentioned.

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. In addition, plastics (e.g., polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, etc.) or conductive particles (e.g., carbon black, silver particles, etc.) are coated with these metals or alloys using a suitable binder. A support in which a plastic or metal substrate is coated with a resin, or a support in which plastic or paper is impregnated with conductive particles can be used.

An undercoat layer having barrier and adhesive functions can 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 5 um or less, preferably 0°1 to 3 μm.
m is appropriate.

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. At this time, poly-N-
Charge transfer complexes consisting of vinyl carbazole and trinitrofluorenone can also be used.

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.

The pigment used in any of the electrophotographic photoreceptors is a disazo pigment represented by the general formula (1). The crystal form of the disazo pigment may be amorphous or crystalline.
It is also possible to use a combination of two or more kinds of disazo pigments shown in the following, or to use them in 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, CRT printers, LED printers, liquid crystal printers, laser plate making,
It can also be widely used in electrophotographic applications such as facsimile printers.

Next, an electrophotographic apparatus and a facsimile equipped with the electrophotographic photoreceptor of the present invention will be described.

FIG. 1 shows a schematic configuration 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 photoreceptor as an image carrier, which is rotated at a predetermined circumferential speed in the direction of the arrow around an axis 1a. The photoreceptor 1 is uniformly charged to a predetermined positive or negative potential on its peripheral surface by the charging means 2 during its rotation process, and then exposed to light image 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 the developing means 4,
The toner developed image is sequentially transferred by the transfer means 5 onto the surface of the transfer material P, which is fed from a paper feeding section (not shown) between the photoreceptor 1 and the transfer means 5 in synchronization with the rotation of the photoreceptor 1. attitude(.

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 produced.
will be printed out on the outside of 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, and subjected to a charge removal process by a pre-exposure means 7, and is repeatedly used for image formation.

As the uniform charging means 2 for the photoreceptor 1, a corona charging device is generally widely used.

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 configured to be detachable from the apparatus main body. It's good. for example,
The photoreceptor 1 and the cleaning means 6 may be integrated into one apparatus unit, and may be configured to be detachable using a guide means such as a rail of the apparatus main body. At this time, the above-mentioned device unit may include a charging means and/or a developing means.

In addition, when an electrophotographic device is used as a copying machine or a printer, light image exposure involves scanning the reflected light or transmitted light from the document, or by reading the document and converting it into a signal. driving the array,
Alternatively, it is performed by driving a liquid crystal shutter array.

Furthermore, when used as a facsimile printer, the optical image exposure is exposure for printing received data.

FIG. 2 is a block diagram showing an example of this case.

The controller 11 controls the image reading section 10 and the printer 19.

The entire controller 11 is controlled by a CPU 17.

The read data from the image reading unit is transmitted to the partner 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.

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 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 out one page of image information from the memory 16 and sends out the one page of image information signaled to the printer controller 18.

The printer controller 18 receives one page of image information from the CPU 17 and 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.

[Example] Examples 1 to 12 5 g of methoxymethylated nylon (weight average molecular weight 32,000) and alcohol-soluble copolymerized nylon (weight average molecular weight 29,000) Log were placed in methanol 95 g on an aluminum support.
A solution dissolved in 100 ml was applied using a Mayer bar to form an undercoat layer having a dry film thickness of 100 ml.

Next, add 5 g of exemplified pigment (1) to 95 mA of cyclohexanone.
2 g of butyral resin (butyralization degree 63 mol%)
was added to the dissolved solution 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 would be 0.2 am, and dried to form a charge generation layer.

Next, 5 g of a hydrazone compound represented by the structural formula below, polymethyl, and methacrylate (weight average molecular weight 100,000) were dissolved in 40 m2 of toluene, and this was placed on a Meyer bar so that the dry film thickness was 20 gm. Apply with
It was dried to form a charge transport layer, and the electrophotographic photoreceptor of Example 1 was prepared.

Example 2 using other exemplary pigments in place of exemplary pigment (1)
All electrophotographic photoreceptors corresponding to Nos. 1 to 12 were prepared in the same manner.

The prepared electrophotographic photoreceptor was negatively charged with a corona discharge of 15 KV using an electrostatic copying paper tester Model 5P-428 manufactured by Kawaguchi Denki ■, held in a dark place for 1 second, and then charged with a halogen lamp. It was exposed to light at an illuminance of 10 lux, and the charging characteristics were evaluated.

The charging characteristics include the surface potential (V,) and the amount of exposure required to attenuate the surface potential by half (El/2) after being left in the dark.
was measured. Show the results.

Comparative Examples 1 and 2 Electrophotographic photoreceptors were prepared in exactly the same manner as in Example 1, except that the azo pigment used in Example 1 was replaced with comparative pigments (A) and (B) shown by the structural formula M2 below. , charging characteristics were similarly evaluated. Show the results.

Comparative pigment (A) (l 4) Comparative pigment (B) 1 (A) 665 3.8
2 (B) 660 4.0
The results show that the electrophotographic photoreceptor of the present invention has sufficient charging ability and excellent sensitivity.

Examples 13 to 15 Using the electrophotographic photoreceptors prepared in Examples 2.8 and 12, fluctuations in bright area potential and dark area potential during repeated use were measured.

As for the method, it was attached to the cylinder of an electrophotographic copying machine 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.

This copying machine is configured to produce an image on transfer paper as a cylinder is driven. .

Initial dark potential ■ using this copying machine. and bright area potential (2) were set at around -700 V and -200 V, respectively, and the amount of variation in dark area potential (Δ■D) and the amount of variation in light area potential (ΔVL) when used repeatedly 5,000 times was measured. 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.

13 -1o +514
−5 +1015 −
15 +5 Comparative Examples 3 and 4 Regarding the electrophotographic photoreceptors prepared in Comparative Examples 1 and 2,
By the same method as in Example 13, potential fluctuations during repeated use were measured. Show the results.

3 -70 +754
-80 +70 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 An undercoat layer of polyvinyl alcohol having a thickness of 0.5 um was formed on the aluminum surface of an aluminum vapor-deposited polyethylene terephthalate film.

A dispersion of the disazo pigment used in Example 4 was applied thereon using a Mayer bar and dried to form a charge generation layer having a thickness of 0.2 μm.

Next, a solution prepared by dissolving 5 g of a styryl compound of the following structural formula and 5 g of polyarylate (condensation polymer of bisphenol A and terephthalic acid-isophthalic acid) in 40 m I2 of tetrahydrofuran was coated on the charge generation layer and dried to form a film with a thickness of 20 m
A charge transport layer of um was formed. The charging characteristics and durability characteristics of the produced electrophotographic photoreceptor were measured in the same manner as in Examples 1 and 13. Show the results.

V, knee 690V El/2: 2.0I2ux-secΔ ■ knee 10
V ΔVL: +5V Example 17 An electrophotographic photoreceptor was prepared by applying the charge generation layer and charge transport layer of the electrophotographic photoreceptor prepared in Example 10 in the reverse order, and the charging characteristics were determined in the same manner as in Example 1. evaluated. however,
The charging was positive.

V o :+705V El/2 : 3. 5j! ux-sec Example 18 On the charge generation layer prepared in Example 9, 5 g of 2,4,7-dolinitro-9-fluorenone and poly-44'-dioxydiphenyl-2,2-propane carbonate (molecular weight 3
A solution obtained by dissolving 5 g of chlorobenzene in 50 mQ of chlorobenzene was applied using a Meyer bar to form a charge transport layer having a thickness of 15 μm after drying.

The charging characteristics of the produced electrophotographic photoreceptor were evaluated in the same manner as in Example 1. However, the charging was positive.

V,: +690V El/2: 4.6j2ux-sec Example 19 2.4.7-) 5 g of Danitro-9-fluorenone and poly-N-vinylcarbazole (number average molecular weight 300,000) 5
A charge transfer complex was prepared by dissolving g in 70 mβ of tetrahydrofuran.

To this charge transfer complex, 1 g of Exemplary Pigment N7) was added and dispersed in a solution in which 5 g of polyester (trade name: Vylon, manufactured by Toyobo ■) was dissolved in 70 m 2 of tetrahydrofuran.

This dispersion was applied onto the undercoat layer prepared in Example 1 and dried to form a photosensitive layer with a thickness of 16 μm.

The charging characteristics of the electrophotographic photoreceptor thus prepared were evaluated in the same manner as in Example 1. The charging was positive.

■. :+690V E 1/2 : 4.8Ji! ux-sec Example 20
~25 The electrophotographic photoreceptors prepared in Examples 5 to 10 were heated to 780n
The electrostatic copying paper tester (
The sample was statically charged with a corona at -5.5 KV using a modified model of Model 5P-428 (mentioned above), held in a dark place for 1 second, and then exposed to laser light to examine the charging characteristics.

The charging characteristics include the surface potential (■.) and the exposure amount (El
/2) was measured. Show the results.

20 5 680 2.5
21 6 685 2.8
22 7 690 3.0
23 8 680 3.1
24 9 700 3.3
25 10 690 3.7
Comparative Examples 5 and 6 The electrophotographic photoreceptors prepared in Comparative Examples 1 and 2 were used in Example 2.
Charging characteristics were measured in the same manner as in Example 0.

5 1 655 5゜
26 2 660 5.
4 As a result of the above, it is known that all the electrophotographic photoreceptors of the present invention have excellent sensitivity to laser light.

[Effects of the Invention] The electrophotographic photoreceptor of the present invention uses a compound with a specific structure in the photosensitive layer, so that the electrophotographic properties of the electrophotographic photoreceptor have high sensitivity, and during continuous image formation by repeated charging and exposure, It is effective in exhibiting the remarkable effect of having small fluctuations in bright area potential and dark area potential and excellent durability.

Furthermore, similar effects can be achieved in an electrophotographic apparatus and a facsimile equipped with the electrophotographic photoreceptor.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a general transfer type electrophotographic apparatus. Reference numeral 1 denotes a drum-type photoreceptor (electrophotographic photoreceptor of the present invention) as an image carrier, 2 a corona charging device, 3 an exposure section, 4
is a developing means, 5 is a transfer means, 6 is a cleaning means, 7
8 is a pre-exposure means, 8 is an image fixing means, L is a light image exposure, and P is a transfer material subjected to image transfer. FIG. 2 is a block diagram of a facsimile machine using an electrophotographic device as a printer. 10 is an image reading unit, 11 is a controller 12 is a receiving circuit, 13 is a transmitting circuit, 14 is a telephone 15 is a line, 16
17 is an image memory, CPU 18 is a printer controller, and 19 is a printer.

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor comprising a photosensitive layer containing a disazo pigment represented by the following general formula (1) on a conductive support. General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (1) In the formula, Ar_1 and Ar_2 are the same or different aromatic hydrocarbon groups that may have substituents that may be bonded via a bonding group, or It represents an aromatic heterocyclic group, A_1 and A_2 are the same or different and represent coupler residues having a phenolic hydroxyl group, and n represents an integer of 2 to 4. 2. An electrophotographic apparatus comprising the electrophotographic photoreceptor according to claim 1. 3. A facsimile comprising an electrophotographic apparatus comprising the electrophotographic photoreceptor according to claim 1 and a receiving means for receiving image information from a remote terminal.