JPS6327848A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body having high sensitivity and reducing changes of the electric potentials of the light and dark parts during repeated electrostatic charging and exposure by forming a layer contg. a specified hyperconjugate compound. CONSTITUTION:A layer contg. a hyperconjugate compound represented by formula I is formed. In the formula I, each of Ar1, Ar2, Ar5 and Ar6 is optionally substituted aryl or an optionally substituted heterocyclic group, each of Ar3 and Ar4 is an optionally substituted bivalent org. group and each of R1-R3 is H, halogen, cyano, optionally substituted alkyl, optionally substituted aryl or optionally substituted aralkyl. The sensitivity of the resulting sensitive body is improved and changes of the electric potentials of the light and dark parts are reduced especially when repeated electrostatic charging and exposure are carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor having a low molecular weight organic photoconductor that provides improved electrophotographic properties. be.

[Prior art]

Various organic photoconductive polymers, including polyvinylcarbazole, have been proposed in the past, but although these polymers are superior to inorganic photoconductive materials in terms of film formability and light weight, The reason why it has been difficult to put it into practical use until now is that sufficient film forming properties have not yet been obtained, and that it is inferior to inorganic photoconductive materials in terms of sensitivity, durability, and stability against environmental changes. It was for the purpose of being there. In addition, hydrazone compounds disclosed in U.S. Pat. No. 4,150,987, triarylpyrazoline compounds described in U.S. Pat.
Low-molecular organic photoconductors such as 9-styrylanthracene compounds described in Japanese Patent Publication No. 8 and Japanese Patent Application Laid-Open No. 51-94829 have been proposed. By appropriately selecting the binder used, such low-molecular-weight organic photoconductors can overcome the drawbacks of film-forming properties that had been a problem in the field of organic photoconductive polymers. It cannot be said that the sensitivity is sufficient.

For these reasons, a laminated structure in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer has been proposed in recent years. Electrophotographic photoreceptors using this laminated structure as a photosensitive layer can now be improved in terms of sensitivity to visible light, charge retention, surface strength, etc. Such electrophotographic photoreceptors are disclosed, for example, in US Pat. No. 3,837,851 and US Pat. No. 3,871,882.

However, electrophotographic photoreceptors that use conventional low-molecular organic photoconductors in the charge transport layer do not necessarily have sufficient sensitivity and characteristics, and especially when repeatedly charged and exposed, the bright area potential and dark area potential There are some points that need to be improved, such as large fluctuations and insufficient high-speed adaptability.

[Problems that the invention attempts to solve]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor that eliminates the above-mentioned drawbacks or disadvantages.

Another object of the invention is to provide a new organic photoconductor.

Another object of the present invention is to provide a novel charge transport material in a laminated photosensitive layer in which a charge generation layer and a charge transport layer are functionally separated.

A fourth object of the present invention is to provide an organic photoconductor with excellent high-speed adaptability.

[Means for solving problems]

This object of the present invention is achieved by an electrophotographic photoreceptor having a layer containing a long conjugated compound represented by the following general formula.

In the general formula, Arl, Ar2, Ar5 and Ar6 are phenyl, naphthyl, anthryl, which may have a substituent,
Aryl groups such as biphenyl, pyrisyl, quinolyl, carbazolyl, chenyl which may have a fused benzene ring,
Ar3 and Ar4 are phenylene which may have a substituent. Arl + Ar2 + Ar31 representing a divalent organic group such as biphenylene, naphthylene, anthrylene, biricene diyl, etc. (wherein R represents a nitroso group, an alkyl group as described above, or an aryl group)
Substituents used for Ar4, Ar5 and Ar6 include alkyl groups such as methyl, ethyl, propyl and butyl, alkoxy groups such as methoxy, ethoxy, propoxy and phenyloxy, and halogen atoms such as fluorine, chlorine, bromine and iodine. , a nitro group, a cyano group, or a trifluoromethyl group. R,, R2, R3 are the above-mentioned alkyl groups, alkoxy groups, halogen atoms, cyano groups, and/or hydrogen atoms, aryl groups such as phenyl, naphthyl, anthryl, biphenyl, which may have substituents, benzyl, phenethyl, Represents an aralkyl group such as naphthylmethyl. Substituents that may be used for the aryl group and aralkyl group are Ar1 and Ar2.

Ar3, Ar4. The examples exemplified by Ar5 and Ar6 may be used.

The compound according to the present invention has a large number of aromatic rings connected by conjugated chains, and the charge flow is thought to be from the Arl and Ar2-substituted amino groups toward the α-phenylstyryl structure of ArS + Ar6. This is undoubtedly related to the extremely high transport ability (mobility) of the carrier as a transport material.And the compound of the present invention has extremely high mobility.
have.

Representative examples of compounds represented by the general formula are listed below.

Compound Examples 8M-1 8M-2 8M-3 8M-4 8M-5 8M-6 8M-7 HM-10 HM-11 8M-12 8M-13 8M-15 HM-16CH3 8M-17 8M-18 8M-20 8M-21 8M-22 8M-23 8M-24 8M-25 8M-26 8M-27 8M-28 8M-29 HM-32 CH3 CH3 8M-35 8M-36 8M-37 8M-39 8M-40 8M-41 8M-42 8M-43 CH3 8M-46 8M-49 8M-50 The compound represented by the general formula (I) used in the present invention is triphenyl represented by the following general formula (n) Ar5 represents a rogene ion. A 1,1-diphenyl derivative represented by a phosphonium group or a dialkyl phosphite group represented by po(OR)2 (where R represents a lower alkyl group) and the following general formula (where Arc, Ar2 .Ar3.Ar4.Ar5+ Ar
6°R, , R2 and R3 are the same as the symbols used in general formula (I). ) can be obtained by reacting with a carbonyl compound represented by:

In a preferred embodiment of the present invention, a compound represented by the above general formula can be used as a charge transport material in an electrophotographic photoreceptor in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer.

The charge transport layer according to the present invention is preferably formed by applying a solution prepared by dissolving the compound represented by the above general formula and a binder in an appropriate solvent and drying the solution. Examples of the binder used here include polyarylate resin, polysulfone resin, polyamide resin, acrylic resin, acrylonitrile resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, phenol resin, epoxy resin, polyester resin, alkyd resin, and polycarbonate. , polyurethane, or copolymer resins containing two or more repeating units of these resins, such as styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, and the like. In addition to such insulating polymers,
Organic photoconductive polymers such as polyvinylcarbazole, polyvinylanthracene and polyvinylpylene can also be used.

The blending ratio of this binder and long conjugated compound is 1
It is preferable that the amount of the long conjugated compound is 10 to 500 parts by weight per 00 parts by weight.

The charge transport layer is electrically connected to the underlying charge generation layer and has the function of receiving and taking charge carriers injected from the charge generation layer in the presence of an electric field and transporting these charge carriers to the surface. have. At this time, this charge transport layer may be laminated on or under the charge generation layer. However, the charge transport layer
It is desirable that it be laminated on the charge generation layer. Since this charge transport layer has a limit in its ability to transport charge carriers, it cannot be made thicker than necessary.

Typically it is 5 microns to 30 microns, with a preferred range of 8 microns to 20 microns.

The charge transport layer of the present invention can contain various additives. Such additives include diphenyl, diphenyl chloride, 0-terphenyl, p-terphenyl, dibutyl phthalate, dimethyl glycol phthalate, dioctyl phthalate, triphenyl phosphoric acid, methylnaphthalene, benzophenone, chlorinated paraffin, dilaurylthiopropionate. , 3,5-dinitrosalicylic acid, and various fluorocarbons.

The charge generation layer used in the present invention includes selenium, selenium-tellurium, pyrylium, thiopyrylium, azulenium dyes,
Phthalocyanine pigments, anthanthrone pigments, dibenzpyrenequinone pigments, pyranthrone pigments, trisazo pigments, disazo pigments, azo pigments, indigo pigments, quinacridone pigments, thiacyanine, asymmetric quinocyanine, quinocyanine or as described in JP-A-54-143645 Separate deposited layers or resin dispersion layers of charge generating materials such as amorphous silicon can be used.

Examples of the charge generating substance used in the electrophotographic photoreceptor of the present invention include the following inorganic compounds and organic compounds.

charge generating material (1) Amorphous silicon (2) Selenium-tellurium (3) Selenium-arsenic (4) Cadmium sulfide (lO) (56).

(58) Squaric acid methine dye (59) Indigo dye (C1!
, No. 78000) (60) Thioindigo dye (C,
1, No. 78800) (61) The β-type copper phthalocyanine charge generating layer can be formed by dispersing the charge generating substance described above in a suitable binder and coating it on the substrate, and also by applying it on the substrate. It can be obtained by forming a vapor deposited film using a vapor deposition apparatus. Binders that can be used to form the charge generating layer by coating can be selected from a wide range of insulating resins and organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene. can. Preferably, polyvinyl butyral, polyarylate (condensation polymer of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin,
Examples include insulating resins such as polyacrylamide resin, polyamide, polyvinylpyridine, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol, and polyvinylpyrrolidone. The resin contained in the charge generation layer is 80% by weight or less, preferably 4% by weight or less.
0% by weight or less is suitable.

The charge generation layer contains as much of the organic photoconductor as possible in order to obtain sufficient absorbance and is preferably a thin film layer, for example less than 5 microns, in order to shorten the range of the generated charge carriers. is preferably a thin film layer having a thickness of 0.01 micron to 1 micron. This means that
Most of the incident light is absorbed by the charge generation layer to generate many charge carriers, and the generated charge carriers must be injected into the charge transport layer without being deactivated by recombination or trapping. Attributable to something.

A photosensitive layer having such a laminated structure of a charge generation layer and a charge transport layer is provided on a substrate having a conductive layer. Examples of substrates having a conductive layer include those in which the substrate itself is conductive;
For example, aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium,
Nickel, indium, gold, platinum, etc. can be used, and in addition, plastics (e.g. , polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyfluorinated ethylene, etc.), conductive particles (e.g., aluminum powder, titanium oxide, tin oxide, zinc oxide, carbon black, silver particles, etc.) in a suitable binder. In addition, plastic or a substrate coated on the conductive substrate, a substrate made of plastic or paper impregnated with conductive particles, a plastic containing a conductive polymer, etc. can be used.

A subbing layer having barrier and adhesive functions can also be provided between the conductive layer and the photosensitive layer. The subbing layer is casein,
Polyvinyl alcohol, nitrocellulose, ethylene-
Acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 6101 copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin,
It can be formed from aluminum oxide, etc.

The thickness of the undercoat layer is suitably 0.1 to 5 microns, preferably 0.5 to 3 microns.

When using a photoreceptor in which a conductive layer, a charge generation layer, and a charge transport layer are laminated in this order, the compound has hole transport properties, so the surface of the charge transport layer must be negatively charged, and if exposed after being charged, it will be exposed to light. In the area, holes generated in the charge generation layer are injected into the charge transport layer, and then reach the surface and neutralize the negative charges, resulting in an attenuation of the surface potential and an electrostatic contrast with the unexposed area. During development, it is necessary to use a positively charged toner, contrary to the case where an electron transport material is used.

In another specific example of the present invention, the above-mentioned disazo pigment or pyrylium dyes, thiapyrylium dyes, selenapyrylium dyes, and benzopyrylium dyes disclosed in U.S. Pat. No. 3,554,745, U.S. Pat. , benzothiapyryllium dye, naphthopyryllium dye, naphthothiapyrylium dye, and other photoconductive pigments and dyes can also be used as sensitizers.

In another specific example, a eutectic complex of a biryllium dye and an electrically insulating polymer having an alkylidene diarylene moiety as disclosed in US Pat. No. 3,684,502 and the like can be used as a sensitizer. This eutectic complex is, for example, 4
-[4-bis-(2-chloroethyl)aminophenyl)
-2,6-cyphenylthiapyrylium perchlorate and poly(4,4'-isopropylidene diphenylene carbonate) are mixed in a halogenated hydrocarbon solvent (e.g. dichloromethane, chloroform, carbon tetrachloride, l,1- Dichloroethane, 1,2-dichloroethane, 1,1.2-
) dichloroethane, chlorobenzene, bromobenzene,
1゜2-dichlorobenzene) and then add a non-polar solvent (for example, hexane, octane, decane, 2゜2-dichlorobenzene) to the solution.
．． A particulate eutectic complex is obtained by adding 4-trimethylbenzene and ligroin. The electrophotographic photoreceptor in this specific example includes styrene-butadiene copolymer, silicone resin, vinyl resin, vinylidene chloride-acrylonitrile copolymer, styrene-acrylonitrile copolymer, vinyl acetate-vinyl chloride copolymer, thread ribinyl butyral, polymethyl methacrylate, Positive-N-butyl methacrylate, polyesters,
Cellulose esters and the like can be contained as a binder.

The electrophotographic photoreceptor of the present invention can be used not only for electrophotographic copying machines, but also for laser printers, CRT printers,
It can also be widely used in electrophotographic application fields such as LED printers and electrophotographic plate making systems.

[Effects of the Invention] According to the present invention, it is possible to provide a highly sensitive electrophotographic photoreceptor, and the variation in bright area potential and dark area potential upon repeated charging and exposure is small, and the conductivity of the carrier is Since the (mobility) is large, it has the advantage of excellent high-speed adaptability.

Hereinafter, the present invention will be explained according to examples.

Example 1 β-type copper phthalocyanine manufactured by Toyo Ink Manufacturing Co., Ltd. (trade name: Lionol Blue NCB Toner)
) was refluxed in water, ethanol and benzene sequentially, and filtered to purify the pigment. 7 g; Product name:
Polyester adhesive 49,000 (solid content 20
A coating solution was prepared by mixing 14 g of %); 35 g of toluene; and 35 g of dioxane, and dispersing the mixture in a ball mill for 6 hours. This coating liquid was applied onto an aluminum sheet using a Mayer bar to a dry film thickness of 0.5 microns to form a charge generation layer.

Next, as a charge transport compound, the above-mentioned exemplified compound) (M-2
A solution obtained by stirring and dissolving 7 g of polycarbonate resin (trade name "Panlite 11300J" manufactured by Ondai Kasei Co., Ltd.) in a mixed solvent of 35 g of tetrahydrofuran and 35 g of chlorobenzene was added to the charge generation layer. The photoreceptor was coated with Mayer Par to a dry film thickness of 16 microns to produce an electrophotographic photoreceptor having a photosensitive layer having a two-chip structure.

The electrophotographic photoreceptor produced in this way was manufactured by Kawaguchi Electric Co., Ltd.
Electrostatic copying paper tester Model-3P-428 was used to statically charge the corona at 15 KV, and the test was carried out in the dark at 1
After holding for a second, it was exposed to light at an illuminance of 51'ux, and the charging characteristics were examined.

The charging characteristics include the surface potential (vo) and the amount of light exposure required to attenuate the potential (V,) when dark decaying for 1 second to %.
Ey2) was measured.

”Furthermore, in order to measure the fluctuations in bright area potential and dark area potential during repeated use, the photoreceptor prepared in this example was attached to the photosensitive drum cylinder of a PPC copier NP-150Z manufactured by Canon Inc. 50,000 copies were made with the same machine, and the bright area potential (V
t, ) and dark potential (Vo) were measured.

Comparative sample 1 was prepared in exactly the same manner using a stilbene compound having the following structural formula in place of the above-mentioned exemplified compound, and measured in the same manner.

The results are shown below.

Table 1 From these results, there is little difference in superiority between the compound of the present invention and the compound of Comparative Example-1.
When measuring the mobility of the charge transport layer (Flight method), it was found that when the mobility of the Canon Co., Ltd. copier NP-3525 is 1, the mobility of Example 1 is 30 times that, while that of Comparative Example 1 was found to be approximately 10 times superior in terms of high-speed adaptability.

In each of Examples 2 to 1, Exemplified Compound HM-2 was replaced with Exemplified Compound HM-2 as the charge transport compound used in Example 1.
(M-1, HM-6, HM-8, HM-11゜HM-1
2, HM-19, HM-20, HM-23゜HM-29
, HM-33, HM-36, HM-38゜HM 41
An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that HM-45, HM-49, and the pigment of Example (44) were used as the charge-generating substance.

The electrophotographic properties of each photoreceptor were measured in the same manner as in Example 1. Further, the mobility μd was measured (same as in Example-1 (the relative value was determined with the mobility of NP-3525 as 1). The results are shown below.

2 HM-10,60700690553HM-
61,070569020 4HM-80,9069567525 5HM-110,70700685306HM-120
,607056952571(M-190,80700
690358HM-200, 60685675709H
M-230, 807006857510HM-290,
657,056953511HM-330,60680
6702012HM-361, 20700690851
3HM-381, 2569568510014HM-4
10,907056904515HM-450,857
006803016HM-490,656956802
0 Initial Example after 50,000 sheets durability vD (-volt) VL (-volt) VD (-
Holt) v Shikuichi Holt) 2 690
40 680 7Q3
695 75 6&5
g55690 50
675 g013 68
5 95 6ri5 1
25 Example 17 An ammonia aqueous solution of casein (11.2 g of casein, 1 g of 28% ammonia water, 22.2 mj of water) was coated on an aluminum cylinder using a dip coating method, and dried to a coating weight of 1.0 g/rrf. A suction layer was formed.

Next, 1 part by weight of the charge generating substance of Example No. 81, 1 part by weight of butyral resin (S-LEC BM-2: manufactured by Sekisui Chemical Co., Ltd.)
Parts by weight and 30 parts by weight of isopropyl alcohol were dispersed for 4 hours using a ball mill disperser. This dispersion was coated on the previously formed undercoat layer by dip coating and dried to give a film thickness of 0.3 microns when the charge generating material was used.

Next, 1 part by weight of long conjugated compound No. HM-3, 1 part by weight of polysulfone resin (P1700, manufactured by Union Carbide), and 6 parts by weight of monochlorobenzene were mixed and dissolved by stirring with a stirrer. This liquid was applied onto the charge generation layer by dip coating and dried to form a charge transport layer. The film thickness at this time was 18 microns.

A corona discharge of 15 KV was applied to the photoreceptor thus prepared. The surface potential at this time was measured (initial potential VO).

Furthermore, the surface potential of this photoreceptor was measured after it was left in a dark place for 5 seconds. Sensitivity is calculated by dividing the potential VK after dark decay by 1/
Exposure required to attenuate to 2 (E% microjoules/
crtr ) was evaluated. At this time, the light source was a gallium/aluminum/propylene ternary semiconductor laser (output: 5 mW, oscillation wavelength: 780 nm).
) was used. These results were as follows.

Vo: -680 Volts Potential holding rate: 90% E%: 0.5 micro units/crd Next, a laser beam printer (LBP-CX manufactured by Canon), which is a reversal development type electrophotographic printer equipped with the same semiconductor laser as above, was used. ), the above photoreceptor was replaced with an LBP-CX photoreceptor, and an actual image forming test was conducted. The conditions are as follows.

Surface potential after primary charging: 700 V, surface potential after image exposure: -150 V (exposure amount: 1.0 μJ/crrr),
Transfer potential: +700V, developer polarity: negative polarity, process speed: 50 mm/sec, development conditions (development bias): -450V1 image exposure scan method: image scan, -th order pre-charging exposure: 501 u
The x-sec red entire surface exposure and image formation were performed by line scanning a laser beam in accordance with character signals and image signals, and good prints were obtained for all three character images.

Example 18 3 g of 4-(4-dimethylaminophenyl)-2,6-cyphenylthiapyrylium verchlorate and 5 g of the above-mentioned conjugated compound (HM-15) were mixed into polyester (Polyester Adhesive 49000: manufactured by DuPont) ) toluene (50)-dioxane (50) solution 100rrl
and dispersed in a ball mill for 6 hours.

This dispersion was applied onto an aluminum sheet using a Mayer bar so that the film thickness after drying was 15 microns.

Example 1 The electrophotographic characteristics of the photoreceptor produced in this way
It was measured in the same manner as. The results are shown below.

Vo knee 690 volts V, knee 680 volts Ey2: 0.8 f ux, sec suction Vo knee 690 volts VL knee 70 volts 50000' VD knee 675 volts VL knee 105 volts Example 19 Ammonia aqueous solution of casein on an aluminum plate (Casein 1
1.2g, 28% ammonia water 1g, water 222mji
was coated with a Mayer bar and dried to form an adhesive layer with a thickness of 1 micron.

Next, 5 g of a disazo pigment having the following structure and 2 g of butyral resin (degree of butyralization: 63 mol%) were mixed with 9 mol of ethanol.
5mj! After being dispersed with a solution dissolved in water, the charge generating layer was coated on the adhesive layer to form a charge generating layer having a dry film thickness of 0.4 microns.

Next, 5 g of the above-exemplified long conjugated compound (HM-40) and 5 g of poly-4,4'-dioxydiphenyl-2,2-propane carbonate (viscosity average molecular fi 30000) were added.
150mj of dichloromethane! An electrophotographic photoreceptor was prepared by applying a solution dissolved in the above liquid onto the charge generation layer and drying it to form a charge transport layer having a thickness of 20 microns.

The electrophotographic properties of the electrophotographic photoreceptor thus prepared were measured in the same manner as in Example 1.

The results are shown below.

Vo knee 700 volts V, knee 690 volts EH: 0.912 ux, 5ec u' Vo knee 670 volts Vt, knee 80 volts 50000' Vo knee 660 volts Vt: -100 volts This photoconductor was manufactured by the aforementioned Canon Corporation. Copy machine NP-35
25 (copying 25 sheets per minute) was modified and attached to a drum with a circumferential speed of double speed, and an image reproduction test was conducted without changing the amount of light, etc., and the images were of extremely good quality. After continuing to copy 5,000 copies, almost no apparent deterioration in image quality was observed.

Example 20 A molybdenum plate (substrate) with a thickness of 0.2 mm whose surface was cleaned was fixed at a predetermined position in a glow discharge deposition tank.

Next, the inside of the tank was evacuated to a vacuum level of about 5×10-'torr. Thereafter, the input voltage of the heater was increased to stabilize the molybdenum substrate temperature at 150°C. After that, hydrogen gas and silane gas (15% by volume relative to hydrogen gas) were introduced into the tank, and the gas flow rate and main valve of the deposition tank were adjusted to 0.5 torr.
stabilized at r. Next, 5 MHz high frequency power was applied to the induction coil to generate glow discharge inside the coil in the tank, resulting in an input power of 30 W. An amorphous silicon film was grown on the substrate under the above conditions, and the same conditions were maintained until the film thickness reached 2 μm, after which glow discharge was discontinued. After that, turn off the heating heater and high frequency power supply, wait for the substrate temperature to reach 100°C, close the hydrogen gas and silane gas outflow valves, and once the temperature inside the tank is below I0-6 t o r r. The pressure was returned to normal and the board was removed. Next, a charge transport layer was formed on this amorphous silicon layer in exactly the same manner as in Example 1 except that exemplified compound HM-2 was used as the charge transport compound.

The photoreceptor thus obtained was placed in a charging exposure experimental apparatus, charged with corona at 196 KV, and immediately irradiated with a light image. The light image was illuminated through a transmission type test chart using a tungsten lamp light source. Immediately thereafter, a good toner image was obtained on the surface of the photoreceptor by cascading a charged developer (containing toner and carrier) onto the surface of the photoreceptor.

Example 21 3 g of 4-(4-dimethylaminophenyl)-2,6-cyphenylthiapyrylium perchlorate and poly(4,4
'-isopropylidene diphenylene carbonate) 3g
200mj of dichloromethane! After sufficiently dissolving, add 100 mj of toluene! was added to precipitate the eutectic complex. After filtering off this precipitate, dichloromethane was added to redissolve it, and then 100 mj of n-hexane was added to this solution. was added to obtain a precipitate of a eutectic complex.

5 g of this eutectic complex was added to 95 mj of a methanol solution containing 2 g of polyvinyl butyral! In addition, the mixture was dispersed in a ball mill for 6 hours. This dispersion was applied onto an aluminum plate having a casein layer using a Mayer bar to form a charge generation layer so that the film thickness after drying was 0.4 microns.

Next, a cover layer of a charge transport layer was formed on this charge generation layer in exactly the same manner as in Example 1 except that exemplified compound HM-4 was used.

The electrophotographic properties of the photoreceptor thus prepared were measured in the same manner as in Example 1. The results are shown below.

V0 knee 695 volts V, knee 675 volts E%: 0.75 1 ux, sec first-Gosho VD knee 700 volts Vt, knee 60 volts W Noritatsu J Jintai 3rd grade VD knee 680 volts VL knee 95 volts Example 22 5 g of the same eutectic complex used in Example 21 and 5 g of the exemplified long conjugated compound (HM-50) were mixed with polyester (
Polyester Adhesive 49000: 150 mjl of tetrahydrofuran solution (manufactured by DuPont)! In addition, the mixture was thoroughly mixed and stirred. This liquid was applied onto an aluminum sheet using a Mayer bar so that the film thickness after drying was 15 μm.

The electrophotographic properties of this photoreceptor were measured in the same manner as in Example 1. The results are shown below.

V0 knee 685 volts ■+: 675 volts E'A: 1-1 1! ux, sec first-1st period VD knee 700 volts Vt knee 90 volts 50000' VD knee 690 volts VL knee 120 volts

Claims (1)

[Scope of Claims] An electrophotographic photoreceptor comprising a layer containing a long conjugated compound represented by the following general formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) However, in the formula, Ar_1, Ar_2, Ar_5 and Ar
_6 is an aryl group or a heterocyclic group, and these groups may have a substituent. Ar_3 and Ar_4 represent a divalent organic group which may have a substituent. Further, R_1, R_2 and R_3 are a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an aryl group or an aralkyl group, and the alkyl group, aryl group and aralkyl group may have a substituent.