JPH0481858A - Electrophotographic photoreceptor, electrophotographic device equipped with the electrophotographic photoreceptor, and facsimile - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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] Conventionally, inorganic photoconductive substances 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-oxadi Those using low-molecular organic photoconductive substances such as azoles, and those in which such organic photoconductive substances are combined with various dyes and pigments are known.

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 one of the dyes and pigments used, and a wide range of studies have been carried out so far. Particularly recently, functionally separated photoreceptors have 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 a low-molecular organic photoconductive substance. Through development, significant improvements have been made in the sensitivity and durability, which were considered to be shortcomings of conventional organic electrophotographic photoreceptors.

Azo compounds exhibit excellent photoconductivity, and because compounds with various properties can be easily obtained by combining the azo component and coupler component, a large number of compounds have been proposed. For example, JP-A-54-22834, JP-A-56-116040, JP-A-58-
Publication No. 70232, Japanese Unexamined Patent Publication No. 131539/1983,
JP-A-61-215556, JP-A-61-241
No. 763 is already known.

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. .

[Problems to be Solved by the Invention] The purpose of the present invention is to provide a novel photoconductive material, and to provide an electrophotographic photoreceptor having practical high sensitivity characteristics and stable potential characteristics during repeated use. Particularly, it is an object of the present invention 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 general formula (1) on a conductive support.

In the general formula, Art, Art and Arm are the same or different and represent a carbocyclic aromatic group or a heterocyclic aromatic group which may have a substituent, and A1 and A2 are the same or different and represent a phenolic hydroxyl group. represents a coupler residue with .

Specifically, carbocyclic aromatic groups include groups such as benzene, naphthalene, and anthracene with two hydrogen atoms removed, or groups with two hydrogen atoms removed from groups such as furan, virolcarboxylic acid, thiophene, pyridine, and pyrazine. Examples of substituents include halogen atoms such as fluorine, chlorine, iodine, and bromine, alkyl groups such as methyl, ethyl, propyl, isopropyl, and butyl, alkoxy groups such as methoxy, ethoxy, and propoxy, and phenoxy. Substituted amine groups such as an aryloxy group, a nitro group, a cyanogen group, dimethylamino, dibenzylamino, diphenylamino, morpholino, piperidino, and pyrrolidino are mentioned.

Preferred examples of the coupler residues having a phenolic hydroxyl group represented by A1 and A2 include residues represented by the following general formulas (3) to (7).

・X (3) x'
(4J-X in formulas (3), (4), and (5) is a naphthalene ring, anthracene ring, carbazole ring, benzcarbazole ring, dibenzofuran ring, etc. which may be fused with a benzene ring and have a substituent. Represents residues necessary to form a polycyclic aromatic ring or a heterocycle.

Y in general formula (7) represents a divalent aromatic hydrocarbon group which may have a substituent or a divalent heterocyclic group containing a nitrogen atom in the ring, specifically O-phenylene, 0-Naphthylene, perinaphthylene, l.

2-Anthrylene, 3,4-Pyrazolediyl, 2.3
-pyridinediyl, 4,5-pyridinediyl, 6,7-
2 such as indazolediyl, 6,7-chiralindiyl, etc.
Examples include valence groups.

R1 and R2 in formulas (3) and (4) represent a hydrogen atom, an alkyl group that may have a substituent, an aryl group, an aralkyl group, or a heterocyclic group, and R+ and Rz both bond to a nitrogen atom. may be used to form a cyclic amino group containing a nitrogen atom in the ring.

R3 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.

R4 in general formula (6) 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 methyl, ethyl, and propyl; specific examples of aryl groups include phenyl, naphthyl, and anthryl; aralkyl groups include benzyl and phenethyl; heterocyclic groups include pyridyl; Groups such as thienyl, carbazolyl, benzimidazolyl, and benzothiazolyl, and cyclic amino groups containing a nitrogen atom in the group 5 include virol, viroline, pyrrolidine, pyrodone, indole, indoline, carbazoleimidazole, pyrazole, pyrazoline, oxazine, and phenoxazine. It will be done.

Examples of 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 cyan group, and a halomethyl group such as trifluoromethyl.

-49 In formula (3), Z represents an oxygen atom or a sulfur atom, and ρ is an integer of O or 1.

The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer comprises a charge generation layer containing a disazo pigment represented by the general formula (1) and a charge transport layer, both of which have two layers.

Note that - in formula (1), A1. A 2 is the general formula (3
), (4) or (5), in which X is a coupler residue condensed with a benzene ring to form a benzcarbazole ring, the pigment has an absorption range in the near-infrared region. Since it spreads to nearby areas, 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.

The specific structure of the exemplified pigment will be expressed by describing only the parts that change in the basic form.

Basic type 1 Exemplary pigment (1) A r + ・ A r 2 ・No. exemplified pigment (2) A r + ・ r 2 : Exemplary pigment (3) A r + ・ r 2 ・(Total exemplified pigment Exemplary pigment (5) ) Exemplary pigment R Ar1.Arz: + Exemplary pigment (11) Pigment (9) Art, Ar2: (X Exemplary Pigment (13) Arl: Arl, Arz: Exemplary Pigment (15) Exemplary Pigment (17) Exemplary Pigment A r + , A r 2 :Hx Exemplary pigment (19) Exemplary pigment (24) Exemplary pigment (25) Ox Exemplary pigment (26) r, Art:+ Exemplary pigment (20) Ar+, Art: Illustrated pigment (2 A r + % A r 2 : −'=1r Exemplary pigment (
22) Exemplary Pigment (23) Exemplary Pigment (27) Exemplary Pigment (28) Ar+ r 2 ・Exemplary Pigment (29) Exemplary Pigment (30) Art , Ar2: + Exemplary Pigment (31) Ar++ r t ・(Filter Exemplary Pigment (32) A r + ・ r 2 ・÷ Basic type 2 Exemplary pigment (36) A r + ・ r t ・(Su Ar 3: Rei exemplified pigment (37) Ar r z : (X Exemplary pigment (38) Art % r z ・Exemplary Pigment Ar h Ar 2 Exemplary Pigment (35) A r + , Ar t Ar3:b- Exemplary Pigment (39) ・(Art.

r t No. Exemplary Pigment (40) Art, Ar2: + Ars: 4 Exemplary Pigment (41) Ar To Ar 2: Calyx Exemplary Pigment (42) Art, Ar2:≦ and Exemplary Pigment (43) Art, Ar2: + Ars : Nito Exemplary Pigment (44) Ar r 2 ・(Sawa H A r + to r2 Arsni Exemplary Pigment (48) Ar + ・ r 2 ・(X Ar3: SE X Exemplary Pigment (49) Ars: (Roasted Exemplary Pigment (45) Exemplary Pigment (46) Exemplary Pigment Exemplary Pigment (50) H A r + , Ars: Art: ((Filter Exemplary Pigment (51) Ars: Beto Exemplary Pigment (52) Exemplary Pigment (53) Ars: 4 Exemplary Pigment (54) H3 Exemplary Pigment (58) Exemplary Pigment (59) Exemplary Pigment (60) Exemplary Pigment (55) Ars: Exemplary Pigment (56) r, Arg: IY Exemplary Pigment (57) Exemplary Pigment ( 61) A r + ・ r 2 ・ (X Exemplary pigment (62) O2 Exemplary pigment (63) Exemplary pigment (64) Exemplary pigment (65) A r + , r a : Exemplary pigment (69) Exemplary pigment (70) r r 2 ・Ars: Cρ exemplified pigment (66) Ars d exemplified pigment (67) r ・Arz s÷ exemplified pigment (68) exemplified pigment (71) exemplified pigment (72) Ar+ ・r 2 ・(n exemplified pigment (73) Arm: - Art, Ar24 Art, Ar2: (To Art, Ara = (X Al-3: + Exemplary pigment (76) The disazo pigment represented by the general formula (1) can be prepared by preparing the corresponding diamine by a conventional method. After converting the tetrazonium salt into a borofluoride salt, zinc chloride double salt, etc., either by cupping with a coupler in an aqueous system in the presence of an alkali,
- 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, A2 in general 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. Synthesize by coupling 1 mole of diamine, or protect one amino group of the diamine with an acetyl group, diazotize it, couple one coupler, and then hydrolyze the protecting group with hydrochloric acid etc. However, it can be synthesized by diazotizing it again and coupling it with the other coupler.

Synthesis example (synthesis of exemplified pigment (2)) 300m12. In a beaker, add 150rnJ2 of water and 22% concentrated hydrochloric acid.
Add 0 mρ (0.23 mol) and (0,032 mol) and cool to 0°C, and dissolve a solution of 4.6 g (0,067 mol) of sodium nitrite in 10 m of water while maintaining the liquid temperature at 5°C. It was added dropwise over 10 minutes.

After stirring for 15 minutes, carbon filtration was performed, and 10.5 g (0,096 mol) of sodium fluoride was added to 9 mol of water in this solution.
The solution was soaked in 0 mI2 with stirring, and the precipitated borofluoride salt was collected by filtration, washed with cold water, washed with acetonitrile, and dried under reduced pressure at room temperature.

Yield: 12.0 g, Yield: 77.8% Next, put 500 mρ of DMF in a 1β beaker, dissolve 1) and cool the liquid temperature to 5°C, and then dissolve the borofluoride salt 9 obtained earlier.
．． 64 g (0,020 mol) was dissolved, and then 5.1 g (0,050 mol) of triethylamine was added dropwise over 5 minutes. After stirring for 2 hours, the precipitated pigment was collected by filtration and D
After washing 4 times with MF and 3 times with water, it was freeze-dried.

Yield 114.0g, 15! Elemental analysis calculated value (%) Actual value (%) C69,4669,35 H3,673,74 N 9.00 9.04 The electrophotographic photoreceptor of the present invention has a -M formula on a conductive support. (
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 solution 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 is, for example, 5 μm. below, preferably 0.
A thin film layer of 1 to lum 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 preferably 80% in terms of content in the charge generation layer.
It is not more than 40% by weight, preferably not more than 40% by weight.

The solvent to be used is preferably selected from those that dissolve the resin but do not dissolve the charge transport layer or undercoat layer, which will be described later.

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 metazole, 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 substance in a solvent together with a suitable binder resin as necessary and coating the layer, and the film thickness is generally 5 to 40 um, but preferably 15 to 30 um. .

Charge transporting substances include electron transporting substances and hole transporting substances. Examples of electron transporting substances include 2゜4,7-trinitrofluorenone, 2,4,5゜7-tetranitrofluorenone, chloranil, and tetranitrofluorenone. Examples include electron-withdrawing substances such as cyanoquinodimethane, and polymerization 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 compounds, hydrazone compounds such as p-diethylaminobenzaldehyde-N, N-diphenylhydrazone, N,N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, α-phenyl-4°-N, N- Styryl compounds such as diphenylaminostilbene, 5-[4-(di-ptolylamino)benzylidene]-5H-dibenzo[a,d]cycloheptene, benzidine compounds, triarylmethane compounds, triphenylamine, or these compounds Examples include polymers having a group consisting of in the main chain or side chain (eg, poly-N-vinylcarbazole, polyvinylanthracene, etc.).

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 photoresists such as poly-N-vinylcarbazole and polyvinylanthracene are used. Examples include conductive polymers.

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, platinum, etc. are used. Plastics (e.g. polyethylene, polypropylene,
Polyvinyl chloride, polyethylene terephthalate, acrylic resin, etc.) or conductive particles (e.g. carbon black, silver particles, etc.) are coated on a plastic or metal substrate with a suitable binder resin, or conductive particles are coated on plastic or paper. An impregnated support or the like 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 μm or less, preferably 0°1 to 3 μm.
m is appropriate.

Another specific example of the present invention is an electrophotographic photoreceptor in which the above-mentioned disazo blood test and a charge transport substance are contained in the same layer. At this time, polyN is used as a charge transport material.
- It is also possible to use charge transfer complexes consisting of vinylcarbazole and trinitrofluorenone.

The electrophotographic photoreceptor of this example can be formed by coating and drying a solution in which the above-mentioned disazo blood and charge transfer complex are dispersed in a suitable resin solution.

The pigment used in any of the electrophotographic photoreceptors is represented by the general formula (1).The crystal form of the disazo blood may be amorphous or crystalline, and if necessary, the pigment shown by the general formula (1) may be amorphous or crystalline.
It is also possible to use a combination of two or more types of disazo blood tests shown in (a) or 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,
It can also be widely used in electrophotographic applications such as LED printers, liquid crystal printers, laser engravings, and 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. 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 exposed to a light image by an image exposure means (not shown) in the exposure section 3, such as 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 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. To go.

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, the transfer device 5 is also widely used as a corona transfer means or -11Ω.

An electrophotographic apparatus is constructed by combining a plurality of components such as the photoreceptor and developing means cleaning means described above into an apparatus unit, and this unit is configured to be detachable from the apparatus main body. Also good. For example, the photoreceptor 1 and the cleaning means 6 may be integrated into one apparatus unit, and may be configured to be removable 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.

Furthermore, when using an electrophotographic device as a copying machine or printer, light image exposure uses the reflected light or transmitted light from the original, or the original is read and converted into a signal, and this signal is used to scan the laser beam and light emitting diode. 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 connects the image reading unit 10 and the printer 19.

Controller] 1 is entirely 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 CPTJ 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 .

When the printer controller 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, while recording the statement on the printer 19,
The next page is being received.

As described above, images are received and recorded.

[Example] Examples 1 to 23 5 g of methoxymethylated nylon CM (weight average molecular weight: 32,000) and 10 g of alcohol-soluble copolymerized nylon (weight average molecular weight: 29,000) were placed on an aluminum substrate in 95 g of methanol.
Apply the solution dissolved in the above using a Mayer bar to form an undercoat layer with a thickness of 1 μm after drying.

Next, 5 g of Exemplary Pigment (2) was added to a solution prepared by dissolving 2 g of butyral resin (butyralization degree 63 mol %) in 95 g of cyclohexanone, 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 0.15 μm, and dried to form a charge generation layer.

Next, 5 g of a fluorene compound represented by the structural formula below and 6 g of a polycarbonate cap (average molecular weight N50,000) were dissolved in 40 g of chlorobenzene, and this was placed on the charge generation layer using a Mayer bar so that the dry film thickness was 16 μm. The electrophotographic photoreceptor of Example 1 was prepared by coating and drying to form a charge transport layer.

Example 2 using other exemplary pigments in place of exemplary pigment (2)
Electrophotographic photoreceptors corresponding to Examples 1 to 23 were prepared in exactly 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 15 lux and the charging characteristics were evaluated.

As for charging characteristics, surface potential (VO) and number of dark places! Exposure amount required for the subsequent surface potential to attenuate by 1/2 (El/2)
was measured. Show the results.

1, (2) 696 0.812
(4) 697 0.743
(5) 700 0.824 (
816990, 70 6 (,14,) Comparative Examples 1 to 5 0, 91 0, 89 0, 98 0, 81 0.71 0, 84 0, 83 1, 10 1, 01 1, 14 1, 00 1, 17 1 , 15 1 , 07 1 , 01 1 , 24 1 , 14 1 , 15 1 , 20 Except that the azo pigment used in Example 1 was replaced with comparative pigments (A) to (E) shown by the following structural formulas, An electrophotographic photoreceptor was prepared in the same manner as in Example 1, and the charging characteristics were evaluated in the same manner. The results are shown below.

Comparative pigment (A) Comparative pigment (B) Comparative pigment (D) Comparative pigment (E) 1 (A) 691 9, 1
2 (B) 692 4.5
3 (C) 697 4.9
4 (D) 696 7.1
5 (E) 697 4.7
This result shows that the electrophotographic photoreceptor of the present invention has sufficient charging ability and excellent sensitivity.

Examples 24 to 46 The electrophotographic photoreceptor prepared in Example 1 was subjected to a -6.5 KV corona charger, an exposure optical system, a developer, a transfer charger, and a charger II.
It was attached to the cylinder of an electrophotographic copying machine equipped with an optical system and a cleaner.

Initial dark potential■. and bright area potential■, respectively -700
V, set at around -200V and used repeatedly 5,000 times.
Δ■L) was measured.

The electrophotographic photoreceptors prepared in Examples 2 to 23 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.

28 + 1 + 4 + 6 = 1 + 4 +11 +4 +3 +7 +4 +11 +14 +13 +9 +15 +17 +21 +9 +14 +13 +16 +11 Comparative Examples 6 to 10 The electrophotographic photoreceptors prepared in Comparative Examples 1 to 5 were compared with Example 24. The amount of potential fluctuation during repeated use was measured using the same method. Show the results.

6 * *7
-69 +698
-71 +639 *
+10 -41
+44* has poor sensitivity and a large residual potential and cannot be initialized, and the above results show that the electrophotographic photoreceptor of the present invention has little potential variation during repeated use.

Example 47 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, the disazo blood test dispersion used in Example 5 was applied with a Mayer bar and dried to a film thickness of 0.
A charge generation layer of 2 um was formed.

Next, a solution prepared by dissolving 5 g of a styryl compound having the following structural formula and 5 g of polycarbonate z type resin (weight average molecular weight 50,000) 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. did.

The charging characteristics and durability characteristics of the produced electrophotographic photoreceptor were measured in the same manner as in Examples 1 and 24. Show the results.

V, knee 698V El/2: 0.70I2ux-sec△VD: 1,0004V ΔV,:OV Example 48 The charge generation layer and charge transport layer of the electrophotographic photoreceptor prepared in Example 8 were coated in the reverse order. Create an electrophotographic photoreceptor,
The charging characteristics were evaluated in the same manner as in Example 1. However, the charging was positive.

■. :+697V El/2+1.3℃ux'sec Example 49 5 g of 3.5-dimethyl-3',5''-di-tert-butylsiphequinone was placed on the charge generation layer prepared in Example 9.
A solution prepared by dissolving 4 g of polycarbonate resin (weight average molecule I: 50,000) in 50 g of a droplet of chlorobenzene (70 parts by weight)-N,N-dimethylformamide (30 MM parts) was coated with a Mayer bar and dried to form a charge film with a thickness of 12 μm. A transport layer 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.

Vo: +697V El/2: 2.9ffux-sec Example 50 Example 11i11 (0.5 g of 32J was dispersed with 9.5 g of cyclohexanone in a vent shaker for 5 hours.

A solution prepared by dissolving 5 g of the charge transporting material used in Example 1 and 5 g of the polycarbonate resin in 40 g of tetrahydrofuran was added thereto, and the mixture was further shaken for 1 hour. The coating liquid thus prepared was applied onto an aluminum substrate using a Mayer bar and dried to form a photosensitive layer with a thickness of 20 um.

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

■. :+696V El/2:3. IJ2ux-sec [Effects of the Invention] The electrophotographic photoreceptor of the present invention uses a disazo pigment with a specific structure in the photosensitive layer, so that the generation efficiency and/or injection efficiency of charge carriers inside the photosensitive layer is improved. It has the remarkable effect of improving sensitivity and potential stability during repeated use, and furthermore, the same excellent effect can be obtained when used in electrophotographic devices and facsimile machines.

[Brief explanation of the drawing]

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. Reference numeral 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 is an image memory, 17 is a 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, Ar_2 and Ar_3 are the same or different and each represents a carbocyclic aromatic group or a heterocyclic aromatic group which may have substituents. In the formula, A_1 and A_2 are the same or different and represent coupler residues having a phenolic hydroxyl group. 2. 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. 3. An electrophotographic photoreceptor comprising a photosensitive layer containing a disazo pigment represented by the following general formula (2) on a conductive support. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (2) In the formula, Ar_1 and Ar_2 are the same or different and represent a carbocyclic aromatic group or a heterocyclic aromatic group which may have substituents, A_1 and A_2 are the same or different and represent coupler residues having a phenolic hydroxyl group. 4. 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 formula (2) and a charge transport layer. 5. An electrophotographic apparatus comprising the electrophotographic photoreceptor according to claim 1. 6. A facsimile machine comprising an electrophotographic apparatus comprising the electrophotographic photoreceptor according to claim 1 and a receiving means for receiving image information from a remote terminal.