JP2002006524A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having low moisture absorption for the base coating layer, superior electrphotographic characteristics and image quality even at a high temperature and high humidity environment, high adhesion strength between a conductive substrate and a photoconductive layer, and with which the photoreceptor can be manufactured without causing dissolution of the coating layer in the coating liquid for the photoconductive layer. SOLUTION: In the electrophotographic photoreceptor, having the base coating layer and photoconductive layer which contains polycarbonate resin successively laminated on the conductive substrate, the base coating layer is formed of a mixture of (A) melamines expressed by general formula (1) and/or guanamines expressed by general formula (2) and polyester resin (B) which is crosslinkable with (A) the melamines and/or guanamines. In the formulae, each of R1 to R10 represents a -CH2OR12 or -(CH2)4OR12 group, wherein R12 is a hydrogen atom or 1-6C alkyl group, and R11 is a 1-6C alkyl group or phenyl group which may have substituents.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic photosensitive member.

[0002]

2. Description of the Related Art In recent years, organic photoconductive materials have been widely used as photoconductive materials for electrophotographic photosensitive members. When this electrophotographic photoreceptor is applied to an electrophotographic apparatus by the Carlson method, first, it is charged by corona discharge, and then, the necessary portion is exposed, and the surface charge is selectively erased only in the exposed portion to form an electrostatic latent image. Then, after attaching a developer called toner, the toner is transferred and fixed on paper or the like. At this time, the photoconductor
(1) It can be charged to a desired potential in a dark place (chargeability),
Characteristics such as (2) little leakage of surface charge in a dark place (potential holding ability), and (3) quick decay of surface potential (light responsiveness) during light irradiation are required.

In order to satisfy these required characteristics, electrophotographic photoreceptors having a photoconductive layer formed by dispersing or dissolving a photoconductive substance and a charge transporting substance in a binder on a conductive substrate are widely used. Have been. However, such an electrophotographic photosensitive member has a defect that white spots are generated in a portion of a printed image that should be a black background when regular development is performed. This defect may be caused by a direct junction between the conductive substrate and the photoconductive layer due to a non-uniform point defect in the photoconductive layer or an uneven surface of the conductive substrate. Conceivable. Therefore, a method of eliminating point defects in the photoconductive layer and nonuniformity of the surface of the conductive substrate by interposing an undercoat layer between the conductive substrate and the photoconductive layer has been studied.

[0004] Materials used for the undercoat layer include ethylene / vinyl acetate resin, casein, polyamide resin, polyvinyl butyral resin, polyvinyl formal resin,
Phenoxy resins, polyester resins and the like are known.
However, when an undercoat layer using these resins is introduced, the environmental characteristics of the electrophotographic photosensitive member tend to deteriorate. Specifically, in a high-temperature and high-humidity environment, development such as deterioration of chargeability and generation of image defects such as white spots and density unevenness occurs. This is because the undercoat layer absorbs moisture in a high-temperature, high-humidity environment, which lowers the volume resistivity of the undercoat layer and eliminates the direct bonding between the conductive substrate and the photoconductive layer. Is considered to be reduced. In addition, when the above-described known resin is used, the adhesion between the conductive substrate and the photoconductive layer is not sufficient, and the photoconductive layer peels off from the conductive substrate during use in an electrophotographic apparatus, thereby causing image defects. May occur.

On the other hand, since a photoconductive layer containing a binder such as a polycarbonate resin is laminated on the undercoat layer, the undercoat layer comes into contact with the photoconductive layer coating solution. These coating solutions are generally acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, ethyl acetate, methylene chloride, toluene, xylene, cellosolve, 1,1,2-trichloroethane, methanol, isopropyl alcohol, isobutyl alcohol, n-butyl alcohol,
Since a solvent such as 1,2-dichloroethane, cyclohexane, cyclohexanone, or dioxane is used alone or as a mixture of two or more, a resin having a strong dissolving power and generally used for the undercoat layer as described above is used. It often dissolves. Among the above known resins, polyvinyl formal resin, polyvinyl butyral resin, polyester resin and the like are effective in improving the adhesion between the conductive substrate and the photoconductive layer. Will dissolve. When the undercoat layer is dissolved in the coating liquid, the material of the undercoat layer is mixed into the photoconductive layer laminated on the undercoat layer, so that not only does the performance of the electrophotographic photoreceptor deteriorate,
When immersion coating or the like is performed, a problem arises in that the material for the undercoat layer is mixed in the coating liquid, and the coating liquid cannot be used. Therefore, the undercoat layer must have excellent solvent resistance to the above-mentioned solvents.

[0006]

SUMMARY OF THE INVENTION The present invention provides an undercoating layer having a low moisture absorption rate, excellent electrophotographic properties and image quality even in a high-temperature and high-humidity environment, and an adhesion between a conductive substrate and a photoconductive layer. It is an object of the present invention to provide an electrophotographic photoreceptor that has high power and can be manufactured without dissolving an undercoat layer in a coating solution for a photoconductive layer.

[0007]

According to the present invention, there is provided an electrophotographic photosensitive member in which an undercoat layer and a photoconductive layer containing a polycarbonate resin are sequentially laminated on a conductive substrate. Is a polyester resin capable of undergoing a cross-linking reaction with melamines represented by the following general formula (1) and / or guanamines (A) represented by the following general formula (2) and the melamines and / or guanamines (A) An object of the present invention is to provide an electrophotographic photosensitive member which is a component formed from a mixture with (B).

[0008]

Embedded image [In the formulas (1) and (2), R ^{1 to} R ¹⁰ each independently represent a hydrogen atom, a —CH ₂ O—R ¹² group or — (CH ₂ ) ₄ —
OR ¹² groups (where R ¹² is a hydrogen atom or a group having 1 to 6 carbon atoms)
R ¹¹ represents an alkyl group having 1 to 6 carbon atoms or a phenyl group which may have a substituent.] In addition, the present invention provides melamines and / or guanamines ( A) and the weight ratio of the polyester resin (B) is (A) /
(B) An electrophotographic photosensitive member having 1/99 to 70/30 is provided.

Further, the present invention provides an electrophotographic photoreceptor wherein the mixture forming the component forming the undercoat layer further contains an ionic low molecular compound (C).

[0010] Further, the present invention relates to the present invention, wherein the ionic low molecular weight compound (C) is at least selected from the group consisting of trimellitic anhydride, pyromellitic anhydride, trimellitic acid, pyromellitic acid, amino acid monomer, amino acid dimer, amino acid trimer and amino acid oligomer. An electrophotographic photoreceptor, which is one type of compound, is provided.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

In the present invention, examples of the conductive substrate include metal plates such as aluminum, aluminum alloy, steel, iron and copper; metal compound plates such as tin oxide, indium oxide and chromium oxide; and conductive particles (for example, carbon black,
Substrates in which silver particles are coated on a plastic together with a suitable binder, plastics, paper, glass, etc., which are made conductive by vapor deposition, sputtering, or the like can be used. These substrates have a cylindrical shape. , Sheets, etc., which are not limited to any shape, size, surface roughness, or the like.

In the present invention, the undercoat layer comprises a melamine represented by the following general formula (1) and / or a guanamine (A) represented by the following general formula (2), and the melamine and / or guanamine ( It is formed by a polyester resin (B) capable of undergoing a cross-linking reaction with A) and an ionic low molecular compound (C) added as required.

[0014]

Embedded image [In the formulas (1) and (2), R ^{1 to} R ¹⁰ each independently represent a hydrogen atom, a —CH ₂ O—R ¹² group or — (CH ₂ ) ₄ —
OR ¹² groups (where R ¹² is a hydrogen atom or a group having 1 to 6 carbon atoms)
R ¹¹ represents an alkyl group having 1 to 6 carbon atoms or a phenyl group which may have a substituent, and the substituent of the phenyl group is, for example, 1 carbon atom.
To 6 alkyl groups. By reacting the melamines and / or guanamines (A) with the polyester resin (B),
It is possible to reduce the number of substituents having a hygroscopic property, reduce the hygroscopic rate of the undercoat layer, and improve the solvent resistance while maintaining the adhesive strength characteristic of the polyester resin.

As specific examples of the melamines represented by the general formula (1) or the guanamines (A) represented by the general formula (2), R ^{1 to} R ^{10 of} melamine, acetoguanamine, benzoguanamine and the like are hydrogen atoms. Certain products are obtained by adding an aldehyde such as formaldehyde to melamine or R ¹¹ -substituted guanamine having one or more, preferably two or more amino groups in one molecule, or further reacting the reaction product with an alcohol or the like. Examples include resins that have undergone an etherification reaction. Specific examples of melamines or guanamines (A) include, for example, melamine, monomethylol melamine, dimethylol melamine, trimethylol melamine, tetramethylol melamine, partially methylolated melamine such as pentamethylol melamine, partially butylolated melamine, hexa Methylol melamine, hexabutyrol melamine, these methylolated melamines or alkyl etherified forms (including partially alkylated forms) of butyrolated melamine, for example, mono (methoxymethyl) melamine, bis (methoxymethyl) melamine, tris (methoxy) Methyl) melamine, tetrakis (methoxymethyl) melamine, pentakis (methoxymethyl) melamine, etc., partially methoxymethylated melamine, partially butoxymethylated melamine, hexakis (meth Kishimechiru) melamine, hexakis (butoxymethyl) melamine, acetoguanamine, benzoguanamine, partially methylolated benzoguanamine, tetramethylol benzoguanamine, and including) such as an alkyl ether embodying (partial alkyl ethers embodying these methylol benzoguanamine and the like.
These resins can be used alone or as a mixture of two or more.

The polyester resin (B) used in the present invention is not particularly limited as long as it is a polyester resin capable of undergoing a cross-linking reaction with the component (A). The polyester resin (B) has a weight average molecular weight of 1 as measured by gel permeation chromatography in terms of standard polystyrene.
It is preferably from 000 to 900,000,
Those having 000 to 300,000 are more preferable.

As the polyester resin (B) used in the present invention, a thermoplastic polyester resin generally represented by the structural formula (3) is preferably used.

[0018]

Embedded image (In the formula, R represents a polyhydric organic acid residue such as a dicarboxylic acid residue, and R ′ represents a polyhydric alcohol residue such as a dihydric alcohol residue and a dihydric phenol residue.) Examples of the polyester resin (B) represented by 3) include, for example, melamines and / or guanamines (A)
Those having polar groups of an acid group such as a carboxyl group or a hydroxyl group capable of undergoing a crosslinking reaction with both ends of the main chain are preferred.
Such resins are polyvalent organic acids, such as terephthalic acid,
Isophthalic acid, benzoic acid derivatives and the like, polyhydric alcohols,
For example, ethylene glycol, propylene glycol,
Diethylene glycol, 1,4-butanediol, α-
It is synthesized by a polycondensation reaction such as transesterification, melt transesterification, and direct esterification with butylene glycol, β-butylene glycol, trimethylene glycol, neopentyl glycol, bisphenol A and the like. The polyhydric organic acid and polyhydric alcohol used may be one kind or a combination of two or more kinds. As such a polyester resin, for example, a Byron resin manufactured by Toyobo Co., Ltd. can be commercially obtained. These may be used in combination as needed.

Melamines and / or guanamines (A)
The weight ratio of (A) / (B) = 1 / 99-70 / 30 is preferable, and the weight ratio of the polyester resin (B) having an acid group or a hydroxyl group is 5 / 95-60 / 40. More preferably, it is within. If the ratio (A) / (B) is less than 1/99, the water absorption tends to increase, and if it is greater than 70/30, the adhesion between the conductive substrate and the photoconductive layer decreases, and Electrophotographic properties, specifically, photoresponsiveness tend to decrease.

Examples of the ionic low molecular weight compound (C) used as required include tetracyanoethylene, trimellitic anhydride, pyromellitic anhydride, trimellitic acid, pyromellitic acid, a dithiobenzylnickel complex, a dithiomaleonitrile nickel complex and the like. Acceptor molecules, donor molecules such as hydrazone derivatives, enamine derivatives and butadiene derivatives, and molecules having an amide bond such as amino acid monomers, amino acid dimers, amino acid trimers and amino acid oligomers. These ionic low molecular compounds may be used as a mixture of two or more. Trimellitic anhydride, pyromellitic anhydride, trimellitic acid, pyromellitic acid, amino acid monomers, amino acid dimers, amino acid trimers and / or amino acid oligomers are preferred from the viewpoint of electrophotographic properties.

By adding the ionic low molecular compound (C), the curing of the undercoat layer can be promoted, and the temperature during curing and the curing time can be shortened. There is also an effect of lowering the potential after exposure. When the ionic low molecular compound (C) is added, the amount thereof is 0.1 to 1 based on 100 parts by weight of the total of melamines and guanamines.
The amount is preferably 00 parts by weight, more preferably 1 to 50 parts by weight.

In the undercoat layer, if necessary, titanium oxide,
Fine particles of aluminum oxide, zirconia, lead lanthanum zirconate titanate, alumina, titanium black, silica, lead titanate, barium titanate and the like can be used alone or in combination of two or more.

As a method for forming the undercoat layer, the melamines and / or guanamines (A), the polyester resin (B), and the ionic low molecular weight compound (C) and fine particles used if necessary are dispersed in a solvent. Can be formed by applying the dissolved solution on a conductive substrate using a coating method such as a dip coating method, a spray coating method, a roll coating method, an applicator coating method, and a wire bar coating method, followed by drying. .

In this case, the solvent used is acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, toluene, ethyl acetate, butyl acetate, methylene chloride, toluene, xylene, cellosolve,
1,1,2-trichloroethane, methanol, isopropyl alcohol, isobutyl alcohol, n-butyl alcohol, 1,2-dichloroethane, cyclohexane,
Solvents such as cyclohexanone and dioxane can be used alone or as a mixture of two or more.

Drying is usually performed at 60 to 180 ° C., preferably 70 to 160 ° C., for 5 to 120 minutes, preferably 10 to 120 minutes.
This is done by heating for ~ 60 minutes.

The thickness of the undercoat layer is usually from 0.01 μm to
20.0 μm, preferably 0.1 μm to 15.0 μm
It is. If the thickness is less than 0.01 μm, it is difficult to form the undercoat layer uniformly, and if it exceeds 20.0 μm, the electrophotographic properties tend to deteriorate.

The photoconductive layer in the present invention comprises a photoconductive substance which absorbs light to generate electric charge, a charge transporting substance which transports the generated electric charge, a polycarbonate resin as a binder, and a plasticizer used if necessary. After uniformly dissolving or dispersing additives such as a curing catalyst, a fluidity imparting agent, and a pinhole controlling agent in a solvent, dip coating, spray coating, roll coating, and applicator are applied on the undercoat layer. It can be formed by applying using a coating method such as a coating method or a wire bar coating method and drying.

Examples of the photoconductive substance include organic pigments such as azoxybenzene, disazo, trisazo, benzimidazole, polycyclic quinoline, indigoid, quinacdrine, phthalocyanine, perylene, and methine. Can be used.

As the charge transport material, fluorin, fluorenone, 2,7-dinitro-9-fluorenone,
-Indeno (1,2,6) thiophen-4-one, 3,
7-dinitro-dibenzothiophene-5-oxide, 1
-Bromopyrene, 2-phenylpyrene, carbazole,
3-phenylcarbazole, 2-phenylindole,
2-phenylnaphthalene, oxazole, oxadiazole, oxatriazole, triphenylamine, imidazole, chrysene, tetraphene, acridene, various hydrazones, styryl compounds, poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole,
1-phenyl-3- (4-diethylaminostyryl)-
5- (4-diethylaminophenyl) pyrazolin, polyvinylpyrene, 2-phenyl-4- (4-diethylaminophenyl) -5-phenyloxazole, polyvinylindoloquinoxaline, 1,1-bis (p-diethylaminophenyl) -4, Examples thereof include 4-diphenyl-1,3-butadiene, polyvinylbenzothiophene, polyvinylanthracene, polyvinylacridine, polyvinylpyrazoline, and derivatives thereof.

As the binder, a polycarbonate resin is used. The polycarbonate resin is not particularly limited. For example, a polycarbonate resin obtained by reacting a dihydric phenol with a carbonate-forming compound such as phosgene or diphenyl carbonate is preferably used. Examples of the dihydric phenol include bisphenol A, bisphenol Z, bisphenol F, bisphenol TP, bisphenol C, bisphenol CH,
Examples include, but are not limited to, bisphenol PH, bisphenol FL, bisphenol E, and the like. The weight average molecular weight of the polycarbonate resin measured by gel permeation chromatography in terms of standard polystyrene is preferably from 20,000 to 200,000, more preferably from 30,000 to 150,000.

If necessary, other resins can be used in combination with the polycarbonate resin. Examples of resins that can be used in combination with the polycarbonate resin include silicone resins, polyamide resins, polyurethane resins, polyester resins, epoxy resins, polyketone resins, polystyrene resins, polymethacrylate resins, polyacrylamide resins, polybutadiene resins, polyisoprene resins, and melamine resins. , Benzoguanamine resin, polychloroprene resin, polyacrylonitrile resin, ethyl cellulose resin, nitrocellulose resin, urea resin, phenol resin, phenoxy resin, polyvinyl butyral resin, formal resin, vinyl acetate resin, vinyl acetate /
Examples thereof include a vinyl chloride copolymer and a polyester carbonate resin. Also, heat and / or photo-curable resins can be used. In any case, there is no particular limitation as long as the resin is electrically insulating and can form a film in a normal state.

Examples of the solvent used for forming the photoconductive layer include acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, toluene, ethyl acetate, methylene chloride, toluene, xylene, cellosolve, 1,1,2-trichloroethane, and methanol. Solvents such as isopropyl alcohol, isobutyl alcohol, n-butyl alcohol, 1,2-dichloroethane, cyclohexane, cyclohexanone, and dioxane can be used alone or in combination of two or more.

The binder resin in the photoconductive layer is 80 to 45 parts by weight based on 100 parts by weight of the total of the photoconductive substance and the charge transporting substance.
0 parts by weight, more preferably 90 parts by weight.
３００300 parts by weight. If the amount is less than 80 parts by weight, the film of the photoconductive layer tends to be non-uniform and the image quality tends to be poor. 4
If it exceeds 50 parts by weight, the sensitivity tends to decrease and the residual potential tends to increase. The amount of the photoconductive substance is preferably 1.0 to 20% by weight, particularly preferably 0.5 to 10% by weight, based on the total amount of the charge transporting substance and the binder.
If the amount of the photoconductive substance is too small, the sensitivity tends to decrease, and if it is too large, the chargeability tends to be poor.

As the plasticizer, halogenated paraffin,
Dimethylnaphthalene, dibutylphthalate and the like can be mentioned. Examples of the fluidity-imparting agent include Modaflow (manufactured by Monsanto Chemical), Acronal 4F (manufactured by Basff), and the like. Examples of the pinhole controlling agent include benzoin and dimethyl phthalate. Each of these is preferably used in an amount of 5 parts by mass or less based on the photoconductive substance that generates electric charges.

To form the photoconductive layer, a photoconductive substance,
After uniformly dissolving / dispersing the charge transporting substance, the binder and the additive in the solvent, the coating liquid is applied onto the undercoat layer by dip coating, spray coating, roll coating, applicator coating, wire bar. It can be formed by applying using a coating method such as a coating method and drying. Further, a dispersion (X) in which all or a part of the photoconductive substance, the binder, and the additive are dispersed in a solvent using a ball mill or the like, and the charge transport material is added to the remaining binder and the additive in the solvent. A method of preparing a dissolved liquid (Y) and then uniformly mixing and dispersing (X) and (Y) may be adopted.

The thickness of the photoconductive layer is usually 5 to 60 μm, preferably 8 to 40 μm. If the thickness is less than 5 μm, the potential tends to decrease at the initial stage, and if it exceeds 60 μm, the electrophotographic properties tend to decrease.

In the electrophotographic photosensitive member of the present invention, a protective layer may be formed on the photosensitive layer. The thickness of the protective layer is 0.
It is from 0.1 to 10 μm, preferably from 0.1 to 3 μm.
When the thickness is less than 0.01 μm, the effect of the protective layer is small and the durability is poor. When the thickness exceeds 10 μm, the sensitivity tends to decrease and the residual potential tends to increase.

When printing is performed using the electrophotographic photosensitive member according to the present invention, after performing charging and exposure in the same manner as in the prior art,
What is necessary is to perform development, transfer an image on plain paper, and fix it.

[0039]

Next, the present invention will be described in detail with reference to examples.

The materials used in the following examples are listed below. Abbreviations are shown in parentheses. (1) Photoconductive substance generating charge τ-type metal-free phthalocyanine (τ-H ₂ Pc) (manufactured by Toyo Ink Mfg. Co., Ltd.) (2) Charge transporting substance 1,1-bis (p-diethylaminophenyl)- 4,4
-Diphenyl-1,3-butadiene (PBD) (3) Ionic low molecular weight compound for undercoat layer Trimellitic anhydride (TMA) (manufactured by Wako Pure Chemical Industries) Pyromellitic acid (PMA) (Wako Pure Chemical Industries, Ltd.) (4) Binder (A) For undercoat layer Melamines represented by general formula (1) and guanamines represented by general formula (2) Melamine resin: melan 2000 (ML2000), solid content 50% by weight, (Trade name, manufactured by Hitachi Chemical Co., Ltd.), average bound formaldehyde number 3.5 / triazine nucleus,
Average number of bonded butyl ether groups 2.1 / triazine nucleus Benzoguanamine resin: melan 365 (ML365),
Solid content 60% by weight, (trade name, manufactured by Hitachi Chemical Co., Ltd.), average bonded formaldehyde number 2.1 / triazine nucleus, average bonded butyl ether group 1.1 / triazine nucleus (B) Polyester for undercoat layer Resin Byron 200 (V200), solid content 100%, (trade name, manufactured by Toyobo Co., Ltd.)

[0041]

Embedded image Byron 290 (V290), solid content 100%, (trade name, manufactured by Toyobo Co., Ltd.)

[0042]

Embedded image Byron 103 (V103), solid content 100%, (trade name, manufactured by Toyobo Co., Ltd.) (C) Binder for photoconductive layer Polycarbonate resin: Lexan 141-111 (L1
41), solid content 100%, (manufactured by GE, trade name), a polycarbonate resin composed of the following repeating units

[0043]

Embedded image Polycarbonate resin: Z- consisting of the following repeating units
PC, solid content 100%

[0044]

Embedded image Example 1 90 g of V200 and 20 g of ML2000 were completely dissolved in 1430 g of tetrahydrofuran. This solution was transferred to an aluminum drum (outer diameter 60.1 mm x tube length 247 m).
mx 2 mm thick) and applied by dipping and coating.
After drying at 60 ° C. for 60 minutes, an undercoat layer having a thickness of 0.5 μm was formed.

Next, 10 g of τ-H ₂ Pc, 100 g of L141 and 800 g of a mixed solvent of methylene chloride and 1,1,2-trichloroethane in a ratio of 1: 1 (weight ratio) were dispersed in a ball mill for 10 hours. In the obtained dispersion, 1
00 g of PBD and 800 g of a 1: 1 (weight ratio) mixed solvent of methylene chloride and 1,1,2-trichloroethane were added and mixed well. The obtained coating solution was applied onto the undercoat layer by dipping and applied, and dried at 120 ° C. for 60 minutes to form a photoconductive layer having a thickness of 20 μm, thereby forming an electrophotographic photosensitive member.

Example 2 80 g of V290 and 20 g of ML2000 were completely dissolved in 1430 g of tetrahydrofuran. Using this solution, an undercoat layer was formed in the same manner as in Example 1. Next, in the same manner as in Example 1, a photoconductive layer was formed on the undercoat layer, and an electrophotographic photosensitive member was formed.

Example 3 80 g of V103 and 20 g of ML2000 were completely dissolved in 1430 g of tetrahydrofuran. Using this solution, an undercoat layer was formed in the same manner as in Example 1. Next, in the same manner as in Example 1, a photoconductive layer was formed on the undercoat layer, and an electrophotographic photosensitive member was formed.

Example 4 80 g of V200 and 20 g of ML365 were completely dissolved in 1430 g of tetrahydrofuran. Using this solution, an undercoat layer was formed in the same manner as in Example 1. Next, a photoconductive layer is formed on the undercoat layer in the same manner as in Example 1.
An electrophotographic photoreceptor was formed.

Example 5 80 g of V290 and 20 g of ML365 were completely dissolved in 1425 g of tetrahydrofuran. Using this solution, an undercoat layer was formed in the same manner as in Example 1. Next, a photoconductive layer is formed on the undercoat layer in the same manner as in Example 1.
An electrophotographic photoreceptor was formed.

Example 6 80 g of V200, 7.2 g of ML2000, 14 g of ML365 were completely dissolved in 1430 g of tetrahydrofuran. Using this solution, an undercoat layer was formed in the same manner as in Example 1. Next, in the same manner as in Example 1, a photoconductive layer was formed on the undercoat layer, and an electrophotographic photosensitive member was formed.

Example 7 80 g of V200, 20 g of ML2000 and 5 g of P
MA was completely dissolved in 1430 g of tetrahydrofuran. Using this solution, an undercoat layer was formed in the same manner as in Example 1. Next, in the same manner as in Example 1, a photoconductive layer was formed on the undercoat layer, and an electrophotographic photosensitive member was formed.

Example 8 90 g of V200, 20 g of ML2000, 5 g of TM
A was completely dissolved in 1430 g of tetrahydrofuran. Using this solution, an undercoat layer was formed in the same manner as in Example 1. Next, in the same manner as in Example 1, a photoconductive layer was formed on the undercoat layer, and an electrophotographic photosensitive member was formed.

Example 9 An undercoat layer was formed in the same manner as in Example 1. Next, a photoconductive layer was formed on the undercoat layer, and an electrophotographic photosensitive member was formed in the same manner as in Example 1 except that L141 in Example 1 was changed to Z-PC.

Comparative Example 1 100 g of V200 was completely dissolved in 1500 g of tetrahydrofuran. Using this solution, an undercoat layer was formed in the same manner as in Example 1. Next, in the same manner as in Example 1, a photoconductive layer was formed on the undercoat layer, and an electrophotographic photosensitive member was formed.

Comparative Example 2 100 g of polyamide resin (trade name: Platabond M9)
95 Nippon Rilsan Co., Ltd.) was completely dissolved in 1500 g of tetrahydrofuran. Using this solution, an undercoat layer was formed in the same manner as in Example 1. Next, Example 1
A photoconductive layer was formed on the undercoat layer in the same manner as in the above to form an electrophotographic photosensitive member.

Comparative Example 3 100 g of formal resin (trade name: # 20, manufactured by Denki Kagaku Kogyo KK) was completely dissolved in 1500 g of tetrahydrofuran. Using this solution, an undercoat layer was formed in the same manner as in Example 1. Next, in the same manner as in Example 1,
A photoconductive layer was formed on the undercoat layer to form an electrophotographic photoreceptor.

Comparative Example 4 80 g of a polyamide resin (trade name: Platabond M99)
5 Japan Rilsan Co., Ltd.) and 20g of ML2000
Was completely dissolved in 1500 g of tetrahydrofuran.
Using this solution, an undercoat layer was formed in the same manner as in Example 1. Next, in the same manner as in Example 1, a photoconductive layer was formed on the undercoat layer, and an electrophotographic photosensitive member was formed.

Comparative Example 5 80 g of formal resin (trade name: # 20 manufactured by Denki Kagaku Kogyo KK) and 20 g of ML2000 were completely dissolved in 1500 g of tetrahydrofuran. Using this solution, an undercoat layer was formed in the same manner as in Example 1. Next, in the same manner as in Example 1, a photoconductive layer was formed on the undercoat layer, and an electrophotographic photosensitive member was formed.

Comparative Example 6 80 g of V200 and 30 g of C2520 (block isocyanate (trade name, manufactured by Nippon Polyurethane Co., Ltd.)
0%) was completely dissolved in 1500 g of tetrahydrofuran. Using this solution, an undercoat layer was formed in the same manner as in Example 1. Next, in the same manner as in Example 1, a photoconductive layer was formed on the undercoat layer, and an electrophotographic photosensitive member was formed. [Evaluation Method of Photoconductor] The electrophotographic characteristics and images of the electrophotographic photoconductor obtained in the above Examples and Comparative Examples were measured at 23 ° C. and 50%
The evaluation was performed in an environment of normal temperature and normal humidity of RH and an environment of high temperature and high humidity of 40 ° C. and 90% RH.

The evaluation of the electrophotographic characteristics and the image was carried out by using an electric potential and an image evaluator (positive charging, normal developing system) using an initial charging potential (V ₀ ) at an applied voltage of 5.5 kV and a wavelength of 78.
The sample was irradiated with 0 μm light for 5 μSec, and evaluated by the post-exposure potential (V _L ) 0.3 seconds after irradiation and the density unevenness on the black solid printed image. Table 1 shows the evaluation results of V ₀ (unit volt), _VL (unit volt), and image characteristics under normal temperature, normal humidity, high temperature, and high humidity environments.

[Method of Evaluating Water Absorption of Undercoat Layer] The water absorption of the undercoat layers obtained in the above Examples and Comparative Examples was examined. The solutions for the undercoat layer obtained in the above Examples and Comparative Examples were each weighed in a metal dish to give a solid content of 2 g, and dried under the same conditions as when the undercoat layer was dried. The weight (tentatively A (g)) of the drawn layer was measured. Then 23
It was left for 4 days in an environment of 90 ° C. and 90% RH to absorb moisture, and the weight (tentatively B (g)) of the undercoat layer after moisture absorption was measured. By applying the result to equation (I), the moisture absorption was calculated,
The results are shown in Table 1.

Moisture Absorption Rate = (BA) / A × 100 (I) [Method for Evaluating Solvent Resistance of Undercoat Layer] The moisture absorption rates of the undercoat layers obtained in the above Examples and Comparative Examples were examined. The solution for the undercoat layer obtained in the above Examples and Comparative Examples was 10 × 50 × 0.1
(Unit: mm) by dip coating on aluminum plate
After drying for a minute, an undercoat layer having a thickness of 0.5 μm was formed. After immersing this plate in a solvent for 1 hour, the state of the undercoat layer was visually observed, and the presence or absence of dissolution of the undercoat layer was examined. This evaluation was performed on two kinds of solvents, tetrahydrofuran and methylene chloride, which have strong dissolving power and were used as the solvent for the photoconductive layer used in the above Examples and Comparative Examples.

[Evaluation of Adhesion] The adhesion between the conductive substrate and the photoconductive layer of the electrophotographic photosensitive member using the undercoat layers obtained in the above Examples and Comparative Examples was examined. In the above Examples and Comparative Examples, the conductive substrate was replaced by 10 instead of the aluminum drum.
An electrophotographic photoreceptor was obtained in the same manner except that an aluminum plate of 0 × 100 × 0.1 mm was used. Next, JIS K5400
8.5.2. Adhesion evaluation by cross-cut tape method
The evaluation was performed by counting the number remaining on the conductive substrate after the tape was peeled off. In this test, the interval between cuts and the number of squares were set at 1 mm and 100 pieces.

[0064]

[Table 1] As can be seen from Table 1, melamines represented by the general formula (1) and / or guanamines (A) represented by the general formula (2) were added to the polyester resin (B) having an acid group or a polar group of a hydroxyl group of the present invention. ) Can reduce the water absorption of each, improve the solvent resistance, and at the same time improve the adhesion.

On the other hand, when only the polyester resin (B) was used without combining the melamines and / or guanamines (A) as in Comparative Example 1, the water absorption was relatively low and the adhesion was good. But poor solvent resistance,
When the photoconductive layer is applied, the undercoat layer dissolves and the film becomes non-uniform, and the density of the black solid image becomes non-uniform. Further, as in Comparative Examples 2 and 3, in an electrophotographic photosensitive member having an undercoat layer using a resin other than the polyester resin (B) without combining melamines and / or benzoguanamines (A), the adhesion is Is improved, but not enough,
Poor resistance to dissolution, high undercoat layer water absorption decrease of V ₀ at a high temperature and high humidity environment, density unevenness of the black solid image is produced. On the other hand, as in Comparative Examples 4 and 5, the heat of the melamine resin represented by the general formula (1) and / or the benzoguanamines (A) represented by the general formula (2) is added to the resin other than the polyester resin (B) of the present invention. When a curable resin is used in combination, the solvent resistance is improved, but insufficient, and the adhesion is poor, so that when used in an electrophotographic apparatus, there arises a problem that the photoconductive film peels off from the substrate. Further, as shown in Comparative Example 6, a thermosetting resin other than the melamines represented by the general formula (1) and / or the guanamines (A) represented by the general formula (2) was added to the polyester resin (B). In the case where is combined, the water absorption rate is increased and the solvent resistance and the adhesion are inferior, so that the density unevenness occurs at any of normal temperature, normal humidity and high temperature and high humidity.

[0066]

As described above, the electrophotographic photoreceptor of the present invention has a low moisture absorption rate of the undercoat layer, has excellent electrophotographic characteristics and image quality even in a high-temperature and high-humidity environment. It does not dissolve in a coating solution such as a charge transport layer and the like, and has excellent stability of image characteristics.

 ────────────────────────────────────────────────── ─── Continued from the front page (72) Inventor Tetsuya Fujii 4-3-1 Higashicho, Hitachi City, Ibaraki Pref. Hitachi Chemical Co., Ltd. Yamazaki Office F-term (reference) 2H068 AA21 AA43 AA44 BA04 BA12 BB23 BB37 BB57 BB54 BB57

Claims (4)

[Claims] 1. An electrophotographic photoreceptor comprising a conductive substrate, on which an undercoat layer and a photoconductive layer containing a polycarbonate resin are sequentially laminated, wherein the component forming the undercoat layer is represented by the following general formula (1): And / or a guanamine (A) represented by the following general formula (2) and a polyester resin (B) capable of undergoing a crosslinking reaction with the melamine and / or guanamine (A). Electrophotographic photoreceptor which is a component to be used. Embedded image [In the formulas (1) and (2), R ^{1 to} R ¹⁰ each independently represent a hydrogen atom, a —CH ₂ O—R ¹² group or — (CH ₂ ) ₄ —
OR ¹² groups (where R ¹² is a hydrogen atom or a group having 1 to 6 carbon atoms)
R ¹¹ represents an alkyl group having 1 to 6 carbon atoms or a phenyl group which may have a substituent.] 2. The weight ratio of melamines and / or guanamines (A) to polyester resin (B) is (A) /
2. The electrophotographic photosensitive member according to claim 1, wherein (B) = 1/99 to 70/30. 3. The electrophotographic photoreceptor according to claim 1, wherein the mixture forming the component forming the undercoat layer further contains an ionic low molecular compound (C). 4. The ionic low molecular weight compound (C) is at least one compound selected from the group consisting of trimellitic anhydride, pyromellitic anhydride, trimellitic acid, pyromellitic acid, amino acid monomers, amino acid dimers, amino acid trimers and amino acid oligomers. The electrophotographic photosensitive member according to claim 3, wherein