JPS63220154A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance sensitivity and to lessen the degradation in electric chargeability arising from pre-exposing fatigue by incorporating a specific random copolymer or block copolymer into a layer in which an electric charge generating material is dispersed. CONSTITUTION:An electric charge generating layer 1 and charge transfer layer 2 are successively laminated on a conductive base 3. The random copolymer or block copolymer which has an oxyethylene group and oxypropylene group and the terminal of the molecule of which is a hydroxyl group is incorporated into the layer 1 in which the charge generating layer is dispersed. Namely, the random copolymer or block copolymer is chemically adsorbed in the charge generating material and provides the recombination center of the charges generated by light absorption and, therefore, the charges generated by the pre- exposing fatigue are quickly recombined and are thereby annihilated, conceivably by which the drop of the charge potential of the photosensitive body is suppressed. The electrophotographic sensitive body which has the high sensitivity, extremely lessens the degradation in the electric chargeability arising from the pre-exposing fatigue and obviates the drop of the charge potential even after repetition of the electrical charging and exposure is thereby obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an improvement in an electrophotographic photoreceptor having a layer in which a charge generating substance is dispersed.

[Prior art]

2. Description of the Related Art Electrophotographic photoreceptors have been known that are provided with a charge generation layer containing a charge generation substance and various resins.

Examples of this include polyvinyl butyral (Japanese Patent Application Laid-open No. 58-105154), fatty acid cellulose ester (
JP-A No. 58-166353), acrylic resin with Tg of 70°C or less and an acid value of 10 to 40 (JP-A No. 58-1920)
No. 40), resin with Tg of 70°C or less, and rg of 75
A mixture of resins with a temperature of ℃ or above
No. 9), which is redispersed by adding a less compatible resin-solvent system to the charge-generating substance-resin-solvent system (Japanese Patent Laid-Open No. 56
-12646), polyvinylpyrrolidone (Unexamined Japanese Patent Publication No. 12646), polyvinylpyrrolidone
-113140), polyvinyl formal resin (Japanese Patent Application Laid-Open No. 61-235844).

However, conventionally known photoreceptors have a problem in that sensitivity and chargeability against pre-exposure fatigue vary depending on the mixing ratio of the charge generating substance and the binder resin.

In other words, in conventional photoreceptors, sensitivity can be increased by reducing the amount of binder resin used for the charge-generating substance, but the chargeability deteriorates significantly due to pre-exposure fatigue, and conversely, the use of binder resin for the charge-generating substance If the amount is increased, it is possible to suppress a decrease in chargeability due to pre-exposure fatigue, but this includes the problem of a significant decrease in sensitivity.

Furthermore, conventional photoreceptors also have the disadvantage that the charging potential decreases significantly when charging and exposure are repeated.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor that is highly sensitive, exhibits significantly less decrease in chargeability due to pre-exposure fatigue, and does not exhibit a decrease in charging potential even after repeated charging and exposure.

〔composition〕

According to the present invention, in an electrophotographic photoreceptor having at least a layer in which a charge generating substance is dispersed on a conductive support,
An electrophotographic photoreceptor characterized in that the layer in which a charge generating substance is dispersed contains a random copolymer or a block copolymer having an oxyethylene group and an oxypropylene group, and a hydroxyl group at the end of the molecule. is provided.

Since the electrophotographic photoreceptor of the present invention contains the random copolymer or block copolymer in the layer in which a charge generating substance is dispersed, it has high sensitivity and significantly reduces chargeability due to pre-exposure fatigue. It is small and has a remarkable effect that the charging potential does not decrease even after repeated charging and exposure.

Generally, high-sensitivity photoreceptors have reduced chargeability due to pre-exposure fatigue. The longer the charge generated by light absorption remains on the photoreceptor in a movable state, and the greater the number of charges, the more significant the reduction in chargeability due to pre-exposure fatigue becomes. In other words, even if a charging operation is performed while the charge generated by light absorption remains, the surface charge will be neutralized by the movement of the remaining carriers, so the surface potential will not rise until the residual potential is consumed. , the rise in surface potential is slower in the pre-exposure fatigue valve, and the apparent charged potential becomes lower.

As a result of intensive study to improve this point, the present inventors found that
It has been found that the above drawbacks can be overcome by incorporating a random copolymer or a block copolymer having oxyethylene groups and oxypropylene groups and a hydroxyl group at the end of the molecule into the layer in which a charge generating substance is dispersed. 1. The present invention has been completed.

The reason why the present invention has such remarkable effects is not necessarily clear at the moment, but the reason is that the random copolymer or block copolymer is chemically adsorbed onto the charge generating substance, and the charges generated by light absorption are recombined. This is thought to be due to the fact that the charge generated due to pre-exposure fatigue quickly recombines and disappears, thereby suppressing a decrease in the charged potential of the photoreceptor.

Furthermore, the effect on pre-exposure fatigue as mentioned above.

The electrophotographic photoreceptor according to the present invention also exhibits similar effects during actual use when charging and exposure are repeated, so compared to conventional photoreceptors, the electrophotographic photoreceptor according to the present invention exhibits the same effect even when charging and exposure are repeated.
The decrease in charging potential is extremely small.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 to 4 are drawings illustrating typical layer structures of the electrophotographic photoreceptor of the present invention.

FIG. 1 shows a structure in which a charge generation layer 1 and a charge transfer layer 2 are sequentially laminated on a conductive support 3, and FIG.
The stacking order of the charge generation layer 1 and the charge transfer layer 2 in the figure is reversed, and the charge generation layer 1 is formed by a coating method such as a spray coating method that does not disturb the charge transfer layer 2. Ru.

FIG. 3 is different from the laminated photosensitive layer shown in FIGS. 1 and 2.

This shows a photoreceptor consisting of a single-layer type photosensitive layer in which one layer has a charge generation function and a charge transfer function.

In FIG. 4, a subbing layer 5 is provided between the conductive support 3 and the charge generation layer 1 in FIG. 1.

Such an undercoat layer 5 can be similarly applied to the structures shown in FIGS. 2 and 3.

When the purpose of the undercoat layer is to prevent light interference in the photoreceptor for laser printers, a light-scattering undercoat layer or a light-absorbing undercoat layer is used, and when the purpose is adhesiveness and flexibility, an adhesive is used. Polyamide, polyester, vinyl chloride with good properties
A resin undercoat layer such as vinyl acetate copolymer or polyvinyl butyral is used.

Next, each constituent material used in the present invention will be explained.

The purpose of the conductive support is to supply charges of opposite polarity to the charged charges to the substrate side.

It is possible to use a material that has an electrical resistance of 101 ΩCm or less and can withstand the conditions for forming the charge generation layer, the charge transfer layer, and the undercoat layer. Examples of these are:

The surfaces of electrically conductive metals and alloys such as Afl, Ni, Cr, Zn, and stainless steel, inorganic insulating materials such as glass and ceramics, and organic insulating materials such as polyester, polyimide, phenolic resin, nylon resin, and paper are vacuum-treated. Examples include those coated with an electrically conductive substance such as AQ, Ni, Cr, Zn, stainless steel, carbon, 5nOs, In2O3, etc., and subjected to conductive treatment by methods such as vapor deposition, sputtering, and spray painting.

The layers in which the charge generating substance is dispersed are shown in FIGS. 1, 2 and 4.
In a laminated type photosensitive layer as shown in the figure, it is constituted as a charge generation layer, and in a single layer type photosensitive layer as shown in Fig. 3, it is formed within the photosensitive layer.

Further, in the laminated photosensitive layer, the charge generation layer is composed of a charge generation substance and a resin binder.

In the present invention, a random polymer or block copolymer having an oxyethylene group and an oxypropylene group and having a hydroxyl group at the end of the molecule is used as the resin binder.

Such copolymers are conventionally known, and various commercially available copolymers can be used in the present invention, but those with a molecular weight of 200 to 500,000, preferably 500,000
~50,000, and the average number of added moles of oxyethylene group is 0.
It is preferable to use one having an amount of 99.9 moles per mol, preferably 5 mol% to 90 mols.

Specific examples of such random copolymers or block copolymers include Newpol; PE-61 manufactured by Sanyo Chemical Co., Ltd.;
, PE-62, PH-64, PH-68, PH-71,
PH-74, PH-75, PE-78, PE-85, P
R-88, PH-108, PH-2700; Newport 75f (-90000; Pluronicum series, P series, F series manufactured by fi Denka Kogyo ■; Evan series manufactured by Daiichi Kogyo Seiyaku ■; Nippon Oil & Fats (manufactured by 11) Examples include pronone 102, 104.105.201.204.208.

Further, the layer in which the charge generating substance of the present invention is dispersed contains the polyoxyethylene polyoxypropylene glycol as a resin binder, but if necessary, other resin binders used in this type of charge generating layer may be used in combination. You can also do that.

Examples of such resin binders include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, and polyacetic acid. Vinyl, polyvinylidene chloride, polyacrylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, Examples include thermoplastic or thermosetting resins such as urethane resins, phenol resins, and alkyd resins.

The total amount of the binder resin is 100% of the charge generating substance.
It is appropriate to use 0.01 to 200 parts by weight, preferably 1 to 50 parts by weight. Also.

The polyoxyethylene polyoxypropylene glycol is used in an amount of at least 0.0% based on 100 parts by weight of the charge generating material.
01 parts by weight, preferably 1 part by weight or more.

Examples of charge-generating substances include C.I. Pigment Blue 25 (Color Index (CI) 21180).

CI Pigment Red 41 (CI 21200),
C.I. Acid Red 52 (CI 45100), C.I. Basic Red 3 (CI 45210), and a phthalocyanine pigment having a porphyrin skeleton,
Azulenium salt pigments, squalic salt pigments, azo pigments with a carbazole skeleton (described in JP-A-53-95033), azo pigments with a stilstilbene skeleton (
(described in JP-A No. 53-138229), azo pigments having a triphenylamine skeleton (described in JP-A-53-1325)
47), azo pigments having a dibenzothiophene skeleton (described in JP-A No. 54-21728), azo pigments having an oxadiazole skeleton (described in JP-A-54-1
2742), azo pigments having a fluorenone skeleton (described in JP-A-54-22834), azo pigments having a bisstilbene skeleton (described in JP-A-54-177)
33), an azo pigment having a distyryloxadiazole skeleton (described in JP-A No. 54-2129), an azo pigment having a distyrylcarbazole skeleton (described in JP-A-54-17734) , a triazo pigment having a carbazole skeleton (JP-A-57-195767).

57-195768), phthalocyanine pigments such as CI Pigment Blue 16 (CI 74100), CI Bat Brown 5 (CI
73410), CI 7303
0) and other indigo pigments, Argo Scarlet B (manufactured by Violet Co., Ltd.).

Organic pigments such as perylene pigments such as Indus Lance Scarlet R (manufactured by Bayer AG) can be used.

Among these charge-generating substances, azo pigments are particularly preferred, and among azo pigments, disazo pigments and trisazo pigments shown below are most preferred.

Specific examples of azo pigments are shown below.

jLLI! IQ-1” Sea face J
L uniform -118--1st grade and length
-Ikoshiichi- IL! u! Q--Koshim- Face J1 Large -i Face JLk --KomlLMk
-Ikoshiichi-jLII! kl--kom 1 and emperor--com salmon ■ long -- koshi m- 1 and long -- ko m 1 and long -i 1 and l -1"shi-ichi face" 1 square
--Kom A glimpse of the face --Kom flLMk
-1"shi-1 face 41nu
-111 face] 1 surprise -6
- The thickness of the charge generation layer 1 is suitably about 0.05 to 2 μm, preferably 0.1 to 1 μm.

The charge generation layer 1 can be formed by dissolving or dispersing a resin binder and a charge generation substance in a suitable solvent, applying the solution, and drying the solution. As a solvent, benzene, toluene, xylene, methylene chloride, dichloroethane, monochlorobenzene, dichlorobenzene, ethyl acetate, butyl acetate, methyl ethyl ketone, dioxane, tetrahydrofuran, cyclohexanone, methyl cellosolve, ethyl cellosolve, etc. can be used alone or in combination. can.

The charge transfer layer 2 can be formed by dissolving or dispersing a charge transfer substance and a resin binder in a suitable solvent, coating the solution on the charge generation layer 1, and drying it. Moreover, a plasticizer, a leveling agent, etc. can also be added if necessary.

Charge transfer substances include poly-N-vinylcarbazole and its derivatives, poly-carbazolylethyl glutamate and its derivatives, pyrene-formaldehyde condensate and its derivatives, polyvinylpyrene, polyvinylphenanthrene, oxazole derivatives, oxadiazole derivatives. , imidazole derivatives, triphenylamine derivatives, 9-(P-diethylaminostyryl)anthracene, 1,1-bis-(4-dibenzylaminophenyl)propane, styrylanthracene, styrylpyrazoline, phenylhydrazones, α-phenylstilbene Examples include electron-donating substances such as derivatives.

Examples of the resin binder include polystyrene used in the charge generation layer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. Coalescence, polyvinyl acetate, polyvinylidene chloride, polyacrylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal,
polyvinyltoluene, poly-N-vinylcarbazole,
Examples include thermoplastic or thermosetting resins such as acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, and alkyd resin.

As the solvent at this time, tetrahydrofuran, dioxane, toluene, monochlorobenzene, dichloroethane, methylene chloride, etc. can be used.

The appropriate thickness of the charge transfer layer 2 is about 5 to 100 microns.

In addition, if the layer in which the charge generating substance is dispersed is a single layer type photosensitive layer as shown in FIG. Furthermore, it can be formed by mixing the charge transfer substance used in the charge transfer layer described above, if necessary, and applying and drying the coating solution on a conductive support or the like.

Furthermore, in the present invention, as described above, an undercoat layer can be provided between the conductive support and the photosensitive layer if necessary.

As described above, the light-scattering subbing layer and the light-absorbing subbing layer are layers intended to prevent light interference in a photoreceptor for a printer. The light-scattering undercoat layer is composed of a conductive powder such as tin oxide or antimony oxide and a white pigment such as zinc oxide, zinc sulfide, titanium oxide, etc. dispersed in a thermosetting resin as shown below. The light-absorbing subbing layer is constructed by dispersing a conductive light-absorbing pigment such as carbon, various metals, and/or a light-absorbing organic pigment in a similar thermosetting resin. The thermosetting resin used here includes, for example, active hydrogen (-OH group, -
It is obtained by thermally polymerizing a compound containing a plurality of hydrogen groups such as NH, group, -NH group, and a compound containing a plurality of isocyanate groups and/or a compound containing a plurality of epoxy groups. Examples of compounds containing a plurality of active hydrogens include polyvinyl butyral, phenoxy resin, phenol resin, polyamide, polyester, and polyethylene glycol.

polypropylene glycol, polybutylene glycol,
Examples include acrylic resins containing active hydrogen such as hydroxyethyl methacrylate groups. Examples of compounds containing a plurality of isocyanate groups include tolylene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, and prepolymers thereof, and examples of compounds containing a plurality of epoxy groups include bisphenol A type epoxy resins. can give.

In any case, the light-scattering or light-absorbing undercoat layer is prepared by coating a liquid in which the above-mentioned components are dissolved or dispersed on the substrate.
It is formed by thermal polymerization at 200°C. The appropriate thickness of this undercoat layer is 1-10 .mu.m. Further, the weight ratio of the conductive powder, the white pigment, and the thermosetting resin is from 2 to 671.
The weight ratio of the light-absorbing pigment to the thermosetting resin is preferably 4 to 9/1 to 6.

〔effect〕

Since the electrophotographic photoreceptor of the present invention contains polyoxyethylene polyoxypropylene glycol in the layer in which a charge generating substance is dispersed, it has high sensitivity and significantly less decrease in chargeability due to pre-exposure fatigue. It has a remarkable effect that the charging potential does not decrease even after repeated charging and exposure.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1 [Coating liquid for charge transfer layer] 5 parts by weight of the azo pigment (pigment Not) shown in Table 1 and polyoxyethylene polyoxypropylene glycol (HO→
c, H40+Wr-4Ca us 0-Cs H,0
1, Nupol PH68, Sanyo Kasei ■, block copolymer] and 160 parts by weight of 2-cyclohexanone solution were mixed in a ball mill for 72 hours to obtain a pigment dispersion, and then added to 100 parts by weight of this pigment dispersion. While stirring, 90 parts by weight of methyl ethyl ketone was added to prepare a charge generation layer coating solution.

[Coating liquid for charge transfer layer]

100 parts by weight of α-phenylstilbene-based charge transfer substance (compound shown below) 800 parts by weight of tetrahydrofuran Next, the above coating liquid for the charge generation layer was coated with a blade onto a 75 μm polyester film substrate on which An was vacuum-deposited. ,
The mixture was dried by heating at 120° C. for 10 minutes to form a charge generation layer having a thickness of about 0.2 μm. Next, a charge transfer layer coating solution having the following composition was applied onto the charge generation layer using a blade, and the coating solution was heated at 120°C for 20 minutes.
A charge transfer layer having a thickness of about 20 .mu.m was formed by heating and drying for a minute to prepare a photoreceptor.

Example 2 A photoreceptor was prepared in the same manner as in Example 1 except that the azo pigment in the charge generation layer coating solution was replaced with pigment No. 39.

Example 3 The coating liquid for the charge transfer layer used in Example 1 was applied to a 75 μm polyester film substrate on which AQ was vacuum-deposited in Example 1.
Apply blade coating in the same manner as above, then dry to about 20μ
Sono's charge transfer layer was formed. Next, the coating solution for the charge generation layer used in Example 1 was spray coated onto this charge transfer layer, and dried by heating at 120° C. for 30 minutes to form a charge generation layer with a thickness of about 0.2 μm, and then exposed to light. created a body.

Example 4 A photoreceptor was prepared in the same manner as in Example 1, except that the α-phenylstilbene compound in the charge transfer layer coating solution was changed to a compound having the structure below.

Example 5 Kneeball PH6 was added to the polyoxyethylene polyoxypropylene glycol used to create the coating solution for the charge generation layer.
8, Sanyo Chemical ■) 0.78 weight percent cyclohexanone solution was replaced with a 0.39 weight percent cyclohexanone solution of polyoxyethylene polyoxypropylene glycol [Neupol 751 (90000, Sanyo Chemical ■, random copolymer)] A photoreceptor was produced in the same manner as in Example 2.

Example 6 90 parts by weight of methyl ethyl ketone used to prepare the coating solution for the charge generation layer was mixed with polyvinyl butyral (trade name: XYH
L, manufactured by Union Carbide Plastics Co.) 0.43
A photoreceptor was prepared in the same manner as in Example 5 except that the weight of the methyl ethyl ketone solution was 90 parts by weight.

Example 7 Fine powder of tin oxide containing 210 parts by weight of anti-oxidant 8
1 part by weight, 5 parts by weight of titanium oxide white pigment powder, and 1 part by weight of polyvinyl butyral (trade name: BL-1, manufactured by Tanezu Kagaku Co., Ltd.)
68 parts by weight of the pigment dispersion was treated with a ball mill for 72 hours, then 47 parts by weight of methyl ethyl ketone was added and treated again with a ball mill for 48 hours.Next, 80 parts by weight of this pigment dispersion was mixed with 8 parts by weight of the pigment dispersion while stirring. A 20% by weight solution of tolylene diisocyanate in methyl ethyl ketone was further mixed to prepare a light scattering undercoat layer coating solution.

Next, the above light-scattering undercoat layer coating solution was applied with a blade onto a 75μ polyester film substrate on which AQ was vacuum-deposited, and cured by heating at 120°C for 30 minutes to form a light-scattering layer of about 2.5μ. A subbing layer was formed.

Next, a photoreceptor was prepared in which a charge generation layer and a charge transfer layer were formed on this light scattering undercoat layer in the same manner as in Example 2.

Comparative Examples 1 and 2 Eupol pH! was added to the polyoxyethylene polyoxypropylene glycol of the charge generation layer coating solution. Example 1-2 except that polyvinyl butyral (trade name: XYHL, manufactured by Union Carbide Plastics Co., Ltd.) was used for 68).
A photoreceptor was prepared in the same manner as described above.

Comparative Example 3 A photoconductor was prepared in the same manner as in Example 3, except that polyvinyl butyral (trade name: XYHL, manufactured by Union Carbide Plastics) was used instead of Niepol PH68) in the polyoxyethylene polyoxypropylene glycol of the charge generation layer coating solution. It was created.

Comparative Example 4 A photoreceptor was prepared in the same manner as in Example 4, except that polyvinyl butyral (trade name: XYHL, manufactured by Union Carbide Plastics) was used instead of knee ball (PH88) in the polyoxyethylene polyoxypropylene glycol of the charge generation layer coating solution. It was created.

Comparative Example 5 A photoconductor was prepared in the same manner as in Example 2, except that polyester (trade name: Vylon 200, manufactured by Toyobo Co., Ltd.) was used instead of Niepol PH68) in the polyoxyethylene polyoxypropylene glycol of the coating liquid for the charge generation layer. did.

Comparative Example 6 Kneepol PE68) 0 was added to polyoxyethylene polyoxypropylene glycol when preparing the coating solution for the charge generation layer.
．． A photoreceptor was prepared in the same manner as in Example 1, except that the 78% by weight cyclohexanone solution was replaced with a 5.88% by weight cyclohexanone solution of polyvinyl butyral (trade name: XYHL, manufactured by Union Carbide Plastics Co., Ltd.).

Comparative Example 7 A photoreceptor was prepared in the same manner as in Example 2, except that tristearyl phosphate was used instead of polyoxyethylene polyoxypropylene glycol (Ninipol PH68) when preparing the coating solution for the charge generation layer.

The photoreceptor for electrophotography was created as described above.

Electrostatic copying paper testing device (Kawaguchi Electric Seisakusho ■, SP 428
The electrophotographic properties were evaluated as follows. First, a corona discharge of 16 KV is applied to each photoreceptor for 20 seconds, during which time the charged potential Vx (
After that, discharge in the dark and when the surface potential reaches 1800V, tungsten light is irradiated to obtain the exposure amount 5 (lux 5ee) required for the surface potential to optically attenuate to 1400V. ) was sought. Then 1 color temperature 285
6 @ tungsten light 100000 lux se
c After irradiation, the charged potential V after photo-fatigue is increased again in the same manner as above,
7 (volt) and the exposure amount S' (lux 5ec) of 0 or more are shown in Table 1.

For the photoreceptor of the type shown in Fig. 2, a corona discharge of ÷7kV was performed for 20 seconds, during which time the charge 4 position v2 was measured 2 seconds after the start of the corona discharge, and then the surface potential was increased to +800V after being left in a dark place. When it reaches the point, irradiate the tungsten light,
The exposure amount S required for the surface potential to be optically attenuated to ÷80V was determined. After that, 1000001ux sa as above
c) The 4th position charge after photofatigue after irradiation, %/, and the exposure amount S' were determined.

[Brief explanation of the drawing]

1 to 4 are schematic cross-sectional views of various electrophotographic photoreceptors according to the present invention. 1; Charge generation layer 2; Charge transport layer 3; Conductive support 4; Single-layer photosensitive layer 5; Undercoat layer Patent applicant: Ricoh Co., Ltd. - Procedural Amendment Patent dated January 3, 1986ゞ84゛“1 n” Suit 1, Indication of the case Patent Application No. 54808, filed in 1988 Address 1-3-6 Nakamagome, Ota-ku, Tokyo Name
(674) Rico Co., Ltd. - Representative Hama 1) Hiro 5, date of amendment order Voluntary 6, number of inventions increased by amendment 0.7. Column 8 of "Detailed Description of the Invention" of the specification subject to amendment, content of amendment (3) Page 44, line 1, "Discharge in a dark place" to "Leave it in a dark place" + 400V. I will correct it.

Claims (1)

[Claims] (1) In an electrophotographic photoreceptor having at least a layer in which a charge generating substance is dispersed on a conductive support, the layer in which the charge generating substance is dispersed has an oxyethylene group and an oxypropylene group, and 1. An electrophotographic photoreceptor comprising a random copolymer or a block copolymer in which is a hydroxyl group.