JPS632071A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the titled body having excellent electrophotographic characteristic and durability, even in case of using an org. photoconductive compd. by incorporating a fluorine contg. polymer having a hydroxy group and a cured film of a specific butyletherfied melamine-formaldehyde resin to a protective layer. CONSTITUTION:The titled body is formed by laminating a conductive layer, a photoconductive layer, and the protective layer in this order. The protective layer contains the fluorine contg. polymer which has the hydroxy group, and has <=1,500 number average mol.wt. and the cured film composed of the butyletherfied melamine-formaldehyde resin which has 2-4 binded formaldehyde groups per one of melamine nucleus and also has 1-2 methylol groups. The photoconductive layer contains an org. photoconductive compd., and comprises the film of the org. photoconductive compd., the film composed of the org. photoconductive compd. and a binding agent, and the composite type film composed of the electrostatic charge generating layer and the electrostatic charge transfer layer, etc. The org. pigment which generates the electric charge, and the electric charge transfer substance are preferably jointly uses as the org. photoconductive compd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Use in Childcare) The present invention relates to an electrophotographic photoreceptor having excellent electrophotographic properties and durability.

(Prior Art) Conventionally, inorganic photoconductive substances such as selenium, zinc oxide, titanium oxide, and cadmium sulfide have been mainly used in electrophotographic photoreceptors that utilize photoconductive substances as photosensitive materials.

However, most of these are highly toxic, and there are problems in the way they are disposed of.

On the other hand, photoreceptors using organic photoconductive compounds are generally less toxic than those using inorganic photoconductive substances, and also have advantages such as transparency, flexibility, light weight, and smoothness. Recently, it has been widely studied because of its advantages in several respects. Among them.

A composite photoreceptor that separates charge generation and transport functions is
The sensitivity, which was a major drawback of conventional photoreceptors using organic photoconductive compounds, can be greatly improved.
Rapid progress has been made in recent years.

However, when a photoreceptor using these organic photoconductive compounds is applied to an electrophotographic device based on the Carlson method, and is repeatedly subjected to charging and exposure, 1.
It is necessary to clean (remove) a small amount of toner remaining on the surface of the photoreceptor using a blade, brush, or the like. By repeating this cleaning process,
The surface of the photoreceptor is worn and damaged, resulting in blurred transferred images and, in some cases, delamination of the charge transport layer and charge generation layer, significantly shortening the life of the photoreceptor.

Due to these problems, photoreceptors are

Strong durability is required.

In order to improve durability, it has been proposed to provide a protective layer on the surface, as disclosed in Japanese Patent Laid-Open No. 52-76928, Japanese Patent Laid-Open No. 54-17732, and the like.

(Problems to be Solved by the Invention) The conventional protective layer as disclosed in the above-mentioned publication does not have a sufficient abrasion resistance effect, and also causes an increase in residual potential and a decrease in sensitivity in electrophotographic characteristics. Therefore, it is desired to develop a protective layer with high abrasion resistance that does not impair electrophotographic properties.

Therefore, the present invention provides an electrophotographic photoreceptor with excellent electrophotographic properties and durability even when an organic photoconductive compound is used.

Means for Solving Problem C) The present invention provides an electrophotographic photoreceptor having a protective layer on one surface, the protective layer comprising:

(a) Hydroxyl group-containing fluoropolymer; and (b) butyl etherified melamine having a number average molecular weight of 1,500 or less and having 2 to 4 formaldehyde and 1 to 2 hismethylol groups per melamine nucleus. The present invention relates to an electrophotographic photoreceptor containing a cured film of formaldehyde resin.

The electrophotographic photoreceptor according to the present invention can be obtained by sequentially laminating a conductive layer, a photoconductive layer, and a protective layer.

In the present invention, the photoconductive layer is a layer containing an organic photoconductive compound, and is a film of the organic photoconductive compound.

There are coatings containing an organic photoconductive compound and a binder, composite coatings consisting of a charge generation layer and a charge transport layer, and the like.

Known organic photoconductive compounds can be used as the organic photoconductive compound. Further, as the organic photoconductive compound, it is preferable to use an organic pigment that generates a charge and a charge transporting substance in combination. Note that the charge generation layer contains an organic pigment that generates charges, and the charge transport layer contains a charge transporting substance.

Organic pigments that generate charges include azoxybenzene, disazo, trisazo, benzimidazole,
Polycyclic quinone type, indigoid type.

Quinacridone series, perylene series, methine series, alpha type.

Pigments known to generate charges, such as metal-free or metallic phthalocyanine-based pigments, having various crystal structures such as β-type, γ-type, δ-type, ε-type, and χ-type can be used. These pigments are one example.

JP-A-47-37453, JP-A-47-3754
Publication No. 4, JP-A-47-18543, JP-A-47
-18544 publication, JP-A-48-43942 publication,
JP-A-48-70538, JP-A-49-1231
Publication No. 1987-105536 1%
-75214 publication, JP-A-53-44028 publication,
It is disclosed in Japanese Patent Application Laid-Open No. 17732/1983.

In particular, τ and τ are disclosed in JP-A-58-182640 and European Patent Publication No. 92.255 in that they are sensitive to long wavelengths (near 800 nm).
', η and η' type gold metal phthalocyanines are preferred.

In addition to these, any organic pigment that generates charge carriers upon irradiation with light can be used.

Among the charge-transporting substances, polymer compounds include poly-17.
N-vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylpyrene.

Polyvinylindoquinoxaline, polyvinylbenzothiophene, polyvinylanthracene, polyvinylacridine, polyvinylpyrazoline, etc.

Among low-molecular compounds, fluorenone, fluorene, z
7-sinitro 9-fluorenone, 4H-indeno(1
, 2,6) Thiophen-4-one, 3,7-sinitrodipenzothiophene-5-oxide, 1-bromopyrene, 2-phenylpyrene, carbazole, 3-phenylcarbazole, 2-phenylindole, 2-phenyl naphthalene, oxadiazole, 1-phenyl-3-(
4-diethylaminostyryl)-5-14-diethylaminostyryl)-5-(4-diethylaminophenyl)
Pyrazoline, 2-(p-dimethylaminophenyl)4-
Examples include (p-diethylaminophenyl)-5-(o-chlorophenyl)-1,3-oquinazole, imidazole, chrysene, tetraphene, acridene, triphenylamine, and derivatives thereof.

When using a mixture of an organic pigment that generates a charge and a charge transporting substance, the weight ratio of the latter/former is 10/1 to 2/1.
It is preferable to mix them in the following proportions.

At this time, 1! If the charge-transporting substance is a high-molecular compound, there is no need to use a binder, but even in this case or even if the charge-transporting substance is a low-molecular compound, the binder must be added to the total amount of these compounds. -C is preferably used in an amount of 500% by weight or less. Also.

When using a low-molecular compound as a charge transport material in the summer,
Preferably, the binder is used in an amount of 30 kg or more by weight. In addition, if a binder is used, a plasticizer.

Additives such as fluidity imparting agents and pinhole inhibitors can be added as necessary.

Examples of the binder include silicone resin, polyamide resin, polyurethane resin, polyester resin, epoxy resin, polyketone resin, polycarbonate resin, polystyrene resin, polymethyl methacrylate resin, and polyacrylamide resin.

Furthermore, thermosetting resins and photocuring resins that are crosslinked by heat and/or light can also be used.

In any case, there are no particular limitations as long as the resin is insulative and can form a film under normal conditions, and the resin can be cured by heat and/or light to form a film. As a plasticizer,
Examples include halogenated paraffin, dimethylnaphthalene, dibutyl phthalate, and the like. As fluidity imparting agents, Modaflow (manufactured by Monsando Chemical Co., Ltd.), Acronal 4
Examples of the pinhole inhibitor include benzoin and dimethyl phthalate. Two of these may be used as appropriate, and the amount thereof may be determined appropriately.

When forming a composite photoconductive layer consisting of a charge generation layer and a charge transport layer, the charge generation layer also contains the above-mentioned organic pigment that generates charges, and the binder is applied to the organic pigment. may be contained in an amount of 500% by weight or less,
In addition, the above-mentioned additives are added in an amount of 5% by weight based on the organic pigment.
It may be added below. Also, 11! The charge transporting layer may contain the charge transporting substance described above, and the binder may be contained in an amount of 500% by weight or less based on the charge transporting substance. Charge transport property/If the substance is a low molecular weight compound,
It is preferable that the binder is contained in an amount of 50% by weight or more based on the compound. The charge transporting layer may contain the above-mentioned additives in an amount of 5% by weight or less based on the charge transporting substance.

The hydroxyl group-containing fluoropolymer used as a material for the protective layer is a polymer having hydroxyl groups and fluorine in 9 molecules, and the hydroxyl groups are present in the molecules so that the hydroxyl value of the 9 polymer is 5 to 100. It is preferable that the hydroxyl value is 8.
It is preferable to set it to 70. If the hydroxyl value is too small, the crosslinking density of the butyl etherified melamine/formaldehyde resin will not increase and the abrasion resistance of the protective layer will not improve. If the hydroxyl value is too large, the compatibility with the butyl etherified melamine/formaldehyde resin will be poor.

The above-mentioned hydroxyl group-containing fluoropolymer includes fluoroethylene such as chlorotrifluoroethylene, trifluoroethylene, f-dorafluoroethylene, and alkyl vinyl ether such as ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, hexyl vinyl ether (even if it is fluorine-substituted). or cycloalkyl vinyl ethers such as cyclohexyl vinyl ether (which may be fluorine-substituted) and hydroxyethyl vinyl ether, hydroxypropyl vinyl ether,
It can be obtained by copolymerizing hydroxyalkyl vinyl ethers such as hydroxybutyl vinyl ether, and also carboxyalkyl vinyl ethers such as carboxyethyl vinyl ether, ethylene, flopylene, imbutylene, vinyl chloride, vinylidene chloride, vinyl acetate, n-butyric acid. It may contain vinyl, methyl methacrylate, methacrylic acid, acrylic acid, etc. as a copolymer component.

Fluoroolefins are in the total amount of the above components.

It is preferable to contain 30 to 70 molti.

Further, the alkyl vinyl ether and cycloalkyl vinyl ether are included in the total amount of the components.

It is preferable to use them in a total amount of 5 to 60 moles. If these are too small, it becomes difficult to dissolve in organic solvents, making it difficult to form nine layers.

The other copolymerization components are preferably used in an amount of 30 molar or less based on the amount of the components.

The fluoropolymer of the present invention has a single weight average molecular weight of 5.00.
It is preferably 0 to 150,000 (in terms of standard polystyrene in liquid chromatography). If the molecular weight is too small, the film will be weak.

If it is too large, the viscosity increases when dissolved in a solvent, making it difficult to form nine layers.

The hydroxyl group-containing fluoropolymer of the present invention also includes zero-order ones.

That is, a graft copolymer having monoreactive carbon-carbon double bonds and having a hydroxyl group is also included in the hydroxyl group-containing fluoropolymer of the present invention.

The fluorine-containing resin has 0.001 to 0.025 mol, preferably 0.003 to 0.015 mol, of 9 reactive carbon-carbon double bonds per 100 g of the resin.

If it is less than 0.001 mol, graft polymerization becomes difficult when polymerizing with component (B), and if it exceeds 0.025 mol, gelation tends to occur during polymerization. Further, the fluorine-containing resin has an alkoxy group or a cycloalkyloxy group. This makes it possible to make it soluble in organic solvents such as soap, xylene, toluene, butyl acetate, and methyl isobutyl ketone.

Furthermore, by containing fluorine, the durability of the protective layer using the graft copolymer obtained according to the present invention is improved.

The above fluorine-containing resin has a zero molecular weight of about 1.000 to
200,000 is preferred.

Particularly preferred is about 10,000 to 100,000. If the molecular weight is too low, durability tends to decrease, and if it is too high, gelation tends to occur when the ethylenically unsaturated monomer is polymerized in the presence of a fluorine-containing resin.

The fluorine-containing resin which is the carrier component is the following copolymer TA+ having a hydroxyl group, maleic anhydride, and acrylic acid.

It can be obtained by reacting an α,β-unsaturated carboxylic acid such as methacrylic acid, acrylic anhydride, methacrylic anhydride, or their acid chloride, or a reactive derivative thereof with a hydroxyl group.

In this case, the α,β-unsaturated carboxylic acid or its hydroxyl group-reactive derivative is a copolymer (a)i having 9 hydroxyl groups.
It is reacted with 0.001 to 0.025% to oog.

Copolymer (al is the same as the hydroxyl group-containing fluoropolymer described above, and is a polymer having a hydroxyl group and fluorine in one molecule, and the hydroxyl group of the 9 polymer is 0.57
It is preferable that there are 100 to 100 in the molecule,
In particular, it is preferable to adjust the hydroxyl value to 3 to 70. If the hydroxyl value is too small, sufficient double bonds cannot be introduced. Moreover, if the hydroxyl value is too large, the solubility in organic solvents tends to be limited.

Copolymer +8) is specifically a fluoroolefin like the hydroxyl group-containing fluoropolymer described above.

The alkyl vinyl ether can be obtained by copolymerizing cycloalkyl vinyl ether and hydroxyalkyl vinyl ether, and may contain other copolymerized components. These ingredients and amounts used are the same as in the case @, but hydroxyalkyl vinyl ether is
Co-X Coalescence (a) It is preferably used so that the hydroxyl value is 0.57 to 100K, particularly preferably 3 to 70.

Examples of the ethylenically unsaturated monomer include alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, isopropyl acrylate, and 2-ethylhexyl acrylate, similar alkyl methacrylates, styrene or havinyltoluene, α -Substituted styrenes such as methylstyrene and lyrostyrene, acrylonitrile, methacrylonitrile, vinyl chloride, vinyl acetate, maleic acid dialkyl esters can be used, and furthermore, 2-hydroxyethyl acrylate, 2-
Hydroxypropyl acrylate.

Hydroxy alkyl acrylates such as 2-hydroxybutyl acrylate, similar hydroxyalkyl methacrylates, monoacrylates or monomethacrylates of polyhydric alcohols such as glycerin and trimethylolpropane, N-methylol acrylamide, N-methylol methacrylamide, etc. Ethylenically unsaturated monomers having the following properties can be used. If necessary, unsaturated amides such as acrylamide and methacrylamide, unsaturated monomers having an oxirane group such as glycidyl methacrylate and glycidyl acrylate, and α,β-unsaturated monomers such as acrylic acid, methacrylic acid, and maleic acid monoalkyl esters Saturated carboxylic acids can be used. If the amount of unsaturated monomers containing unsaturated amide and oxirane groups is too large, the water resistance of the coating film tends to decrease or the amount of reaction solvent is limited. It is preferable to use the amount of α,β-unsaturated carboxylic acid in an amount of 30% by weight or less based on the total amount of carboxylic acids.
Preferably used below.

Further, the ethylenically unsaturated monomer having a hydroxyl group is appropriately used so that the hydroxyl value of the resulting graft copolymer is from 5 to 100, particularly from 8 to 70.

The fluorine-containing resin and the ethylenically unsaturated monomer are preferably used in a weight ratio of 9 to 99,510.5. When this ratio is 50150 or more, durability, especially durability during long-term use, is excellent. Further, from the viewpoint of solubility of the organic solvent, the above weight ratio is preferably 99.510.5 or less. The above weight ratio is
Particularly preferred is 60/40 to 9515.

The polymerization of the ethylenically unsaturated monomer in the presence of the fluorine-containing resin can be carried out using toluene, xylene, methylinobutyl ketone, butyl acetate, if necessary.

Ethyl acetate, acetic acid superrosolve, butyl cellosolve.

1-butanol, 2-butanol, 1-propanol.

9. Pe/diyl peroxide as a polymerization catalyst using an organic solvent such as 2-propatol as a reaction solvent. This can be carried out by heating the reaction at 50 to 200°C for 1 to 10 hours using peroxides such as ditertiary butyl peroxide and cumene hydroperoxide, and azobis compounds such as azobisisobutyronitrile. . The reaction is preferably carried out in an atmosphere of an inert gas such as nitrogen gas or under a stream of air.As a single polymerization catalyst, peroxide is preferable in order to improve the grafting rate.In order to reduce the amount of residual monomer, peroxide is preferable. It is preferable to use the compound and the azobis compound together. Polymerization can be carried out not only by bulk polymerization and solution polymerization as described above, but also by condensation polymerization, emulsion polymerization, etc., if necessary.

Butyl etherified melamine used in the present invention
The number average molecular weight of the formaldehyde resin is 1.500 or less, and if the number average molecular weight exceeds 1.500, the reactivity decreases. The resin also has 2 to 4 bound formaldehydes per melamine core. If the number exceeds 4, the reactivity decreases, and if the number is less than 2, the storage stability of the resin deteriorates.
The cured coating becomes brittle. Furthermore, the resin has 1 to 2 methylol groups per melamine nucleus. If the number of methylol groups exceeds 2, the storage stability of the resin will be poor and the cured coating will become brittle. Moreover, if it is less than one, the reactivity is poor.

Such butyl etherified melamine/formaldehyde resin can be produced by dissolving melamine in butanol and adding formaldehyde dropwise thereto to perform an addition reaction and butyl etherification reaction, or by dissolving melamine and formaldehyde in butanol and heating the solution. It can be produced by a method of carrying out an addition reaction and a butyl etherification reaction. In these methods the reaction is nitric acid.

It is preferable to add an acidic catalyst such as hydrochloric acid, sulfuric acid, phosphoric acid, or p-)luenesulfonic acid, and carry out the reaction under acidic conditions, preferably at pH 3 to 6.9 The reaction temperature is the reflux temperature of butanol, preferably about 90 to 100°C. It is preferable that In the present invention, it is preferred to carry out the reaction using 4 to 5 moles of butanol and 3 to 7 moles of formaldehyde per mole of melamine.

The protective layer in the present invention is composed of a cured film of the hydroxyl group-containing fluoropolymer and the butyl etherified melamine/formaldehyde resin. Mix it so that it becomes 1/7 to 1/15.

It is preferably obtained by heating and curing. In this case, the heating temperature is preferably 90 to 140°C. Also, when converting to f,
Hydrochloric acid, p-1-luenesulfonic acid, etc. may be present as a catalyst. This catalyst is preferably used in an amount of 1 weight or less based on the total amount of the polymer and resin.

The protective layer of the present invention includes silicone resin, polymethyl methacrylate resin, epoxy resin, polycarbonate resin,
Polyester resin, polystyrene resin, etc. can be used in combination as a binder.

These are preferably 50% by weight or less based on the total amount of the binder. As the amount of these used increases, the effect of using the fluorine-containing copolymer decreases.

The protective layer can contain the various additives used in the photoconductive layer by appropriately selecting them, and the amount of the additives can also be determined as appropriate.

In the present invention, the conductive layer is a conductive material such as paper or plastic film subjected to conductivity treatment, a plastic film laminated with metal foil such as aluminum, or a metal plate.

The electrophotographic photoreceptor of the present invention has an organic photoconductive layer formed on a conductive layer, and a protective layer formed thereon. The thickness of the photoconductive layer is preferably 5 to 50 microns. If a composite type of charge generation layer and charge transport layer is used as photoconductive layer, the thickness of the charge generation layer is preferably from 0.001 to 10 .mu.m, particularly preferably from 0.2 to 5 .mu.m. O,OO1μm
Less than '1! It becomes difficult to uniformly form the charge generation layer, and if the thickness exceeds 10 μm, the electrophotographic properties tend to deteriorate.

The thickness of the charge transport layer is preferably 5 to 50 μm, particularly preferably 8 to 20 μm. When the thickness is less than 5 μm, the initial potential tends to be low, and when it exceeds 50 μm, the sensitivity tends to decrease.

The thickness of the protective layer is preferably 0.01 to 10 μm.

Particularly preferably, it is 0.1 to 5 μm. 0.01 μm vermilion is less effective as a protective layer and has poor durability.
If it exceeds 5 μm, the sensitivity tends to be poor and the residual potential tends to increase.

In order to form a photoconductive layer on the conductive layer, the organic photoconductive compound and other components are vapor-deposited on the conductive layer, and the organic photoconductive compound and other components are mixed with acetone, a ketone solvent such as methyl ethyl ketone, or an ether such as tetrahydrofuran. solvents, aromatic solvents such as toluene and xylene, halogenated hydrocarbon solvents such as methylene chloride and carbon tetrachloride, methanol,
2. Uniformly dissolve or disperse in an alcoholic solvent such as ethanol or glopanol and apply on the conductive layer. There are several methods of drying. The same method can be used to form a charge generation layer and a charge transport layer, but in this case, either the charge generation layer or the charge transport layer may be the upper layer, and the charge generation layer may be a two-layer charge transport layer. You can also make it colder.

The protective layer may be formed in the same manner as the coating and drying method used in forming the photoconductive layer.

The electrophotographic photoreceptor according to the present invention may further have a thin adhesive layer or barrier layer immediately above the conductive layer.

(Example) Each material used in the examples below is listed below.

The abbreviation in parentheses and the product name and company in parentheses.

(1) Organic pigment phthalocyanine type diτ metal-free phthalocyanine (H2P) that generates electric charge.
C) (2) Charge transport substance oxazole derivative: 2-(p-dimethylaminophenyl)-4-(p-dimethylaminophenyl)-5-(o-chlorophenyl)-1,3-oxazole (OXZ') (3) Binder-free polyester resin: Hylon 200 (V-200) [Toyobo ■] O silicone face: KR-255 (KR255) [Shin-Etsu Chemical ■] O fluorine-containing copolymer: Lumiflon LP-100 (LF
loo) [Asahi Glass■] This has a zero weight average molecular weight of 20,000 to 25,000° and a hydroxyl value of 52. IJ is a copolymer of fluoroethylene, hydroxyalkyl vinyl ether, and alkyl vinyl ether (chlorotrifluoroethylene with an acid value of O), and contains about 50 mole of chlorotrifluoroethylene, and has a solid content of 50 mole in a mixed solvent of xyl and methyl isobutyl ketone.
It is melted at the weight station.

o Lumif 0:/LF-400 (LF400) [Asahi Glass ■] This is similar to LFloo, but the weight average molecular weight is so, ooo ~ 70,000. Hydroxyl value 47 and acid value 5
It is.

O-butyl etherified melamine/formaldehyde resin:
(BMF) (Synthesis of BMF) 126 g of melamine, 4449 n-butanol, and 0.29 nitric acid aqueous solution were placed in a flask equipped with a stirrer, a reflux condenser, and a thermometer, and the temperature was raised to 100'CK.
169 g of paraformaldehyde was added in 6 portions over 30 minutes at equal intervals, and then reacted at reflux temperature for 30 minutes to remove water.

The solvent was removed so that only 50% of the residue remained after heating.

The resulting resin had a viscosity of B according to Gardner (25°C). The number of formaldehyde bound, the number of butyl ether groups, the number of methylol groups, and the number average molecular weight per stick of melamine resin of BMF are shown in Table 1 below.

However, the number of bound formaldehyde is determined by measuring the amount of unreacted formaldehyde using the charged amount and the sodium sulfite method, and the number of butyl ether groups is determined by measuring the amount of butanol charged and the amount of unreacted butanol by gas chromatography using 5ec-butyl alcohol as an internal standard solution. The methylol group was determined by measurement, and the number of butyl ether groups and N
It was determined from the MR spectrum. Further, the number average molecular weight was determined by gel permeation chromatography using a standard polystyrene calibration curve.

Table 1 Comparative Example A mixed solution of HzPc 2-Og, KR2552, Og and methanol 809 was milled in a ball mill (Nihon Kagaku Togyo 3).
The mixture was kneaded for 8 hours using a small-sized bot mill.

This dispersion was applied onto an aluminum plate (conductive layer) using an applicator and dried at 100°C for 1 hour to a thickness of approximately 1 μm.
A charge generation layer was formed. next.

oxzxog and 1 og of Byron 200 were completely dissolved in tetrahydrofuran sog*.

This solution was applied onto the charge generation layer using an applicator and dried at 90° C. for 20 minutes to form a charge transport layer with a thickness of 15 μm, thereby producing an electrophotographic photoreceptor without a protective layer.

Examples 1 to 4 A charge generation layer and a charge transport layer were formed on a conductive layer in the same manner as in the above comparative example. Next, the mixing ratio of LF-100 and BMF is 1/7 or 1/15 in solid weight ratio of the former/latter.
．． The mixing ratio of LP-400 and BMF is 1/7 or 1/15 in the former/latter solid content weight ratio, and the solid content is 5 to 20.
The resulting solution was diluted with t-butanol so as to give a weight percent concentration, and the resulting solution was applied onto the charge transport layer described in Section I using an applicator.

The mixture was cured by heating at 120° C. for 1 hour to obtain an electrophotographic photoreceptor having a protective layer having a thickness shown in Table 1. The electrophotographic properties of the obtained electrophotographic photoreceptor were measured using an electrostatic recording tester (5P-428 manufactured by Kawaguchi Electric). The results are shown in Table 2.

In addition, the initial potential '\o (V') in Table 9 indicates the charging potential when a -5KV corona is discharged for 10 seconds in dynamic measurement, and the dark decay (Vk) indicates the charge potential after 30 seconds in the dark.
It shows the light amount value from the potential (V2O) when left for 0 seconds until the potential becomes half. still.

The spectral sensitivity at 800 nm (S800) is 800 nm using a halogen lamp as the light source and a monochromator at A.
Irradiate the monochromatic light with the spectral light, find the time t (s) required for the potential after irradiation to be halved, multiply this by the energy of the irradiated light (mW/m'), and take the reciprocal. This is what I asked for.

Furthermore, using a friction tester (manufactured by Suga Test Instruments), the surface of the electrophotographic photoreceptor was rubbed with gauze, and the number of times fiber traces of the gauze were visually confirmed on the surface of the photoreceptor is shown in Table 1 as the abrasion resistance.

(Effects of the Invention) The electrophotographic photoreceptor according to the present invention exhibits excellent electrophotographic properties, good dark decay, and high sensitivity. especially.

In some cases, it has high spectral sensitivity at 800 nm.

An LBPK equipped with a diode laser having an oscillation wavelength in the near-infrared region is also applicable. Furthermore, the abrasion resistance of the electrophotographic photoreceptor of the present invention is extremely high.

As described above, the electrophotographic photoreceptor according to the present invention has high electrophotographic properties and durability.

・11. ::j,’ Procedural amendment (formality) July 14, 1982 1986 Patent Application No. 41022 λInvention name electrophotographic photoreceptor 3. Person who makes corrections 4. Deputy manager June 30, 1986 (Shipping mortar) 6. Subject of correction ゛　Detailed description of the invention in the specification 7. Contents of correction

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor having a protective layer on the surface, the protective layer comprising (a) a hydroxyl group-containing fluoropolymer and (b) a number average molecular weight of 1,500 or less, with melamine nuclei 1
Butyl etherified melamine with 2 to 4 formaldehyde bonds and 1 to 2 methylol groups per unit.
An electrophotographic photoreceptor containing a cured film of formaldehyde resin.