JPS61105550A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance mechanical strength and to prevent crystallization and solvent cracking in an electrostatic charge transfer layer by forming a charge generating layer and a charge transfer layer using a specified polycarbonate resin. CONSTITUTION:The binder polymer used for the charge transfer layer is a copolycarbonate derived from bisphenol A represented by formula 1 and a dioxy compd. represented by formula 2, in a preferable ratio of 1:19-19:1, especially, 1:9-4:1, and a preferable mol.wt. of said polymer is 10,000-150,000. In formulae 1, 2, each of X, Y is H, halogen, or methyl, and R is H, halogen, OH, COOH, acetyl, or 1-4C alkyl.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and more particularly, to a photoreceptor derived from bisphenol (A) and other dioxy compounds as a binder polymer of a charge transport layer. The present invention relates to an electrophotographic photoreceptor having a charge transport layer using a modified polycarbonate resin of a copolymer.

[Prior art]

Recent electrophotographic photoreceptors have become mainstream of laminated organic electrophotographic window photoreceptors having at least two layers: a charge generation layer that generates charges upon exposure and a charge transport layer that transports charges.

In general, organic photoreceptors are produced by forming an additional layer through a coating process on a film such as PET (polyethylene terephthalate) on which a conductive layer has been formed by a method such as vapor deposition.
A flexible photoreceptor can be produced. Since such a photoreceptor can be processed into a belt shape and used repeatedly in an electrophotographic copying machine, it has the advantage that the degree of freedom in the shape of the hardware of the copying machine can be expanded.

In this laminated photoreceptor, bisphenol (A) polycarbonate resin is widely used as a binder polymer for the charge transport layer.

Bisphenol (A) polycarbonate resin has good compatibility with charge transport materials, so when it is produced as a photoreceptor, it has good electrical properties and relatively strong mechanical strength.

However, when a charge transport layer is formed using a bisphenol (A) polycarbonate resin as a binder polymer for the charge transport layer of an electrophotographic photoreceptor,
It has become clear that there are some problems.

First, when manufacturing the photoreceptor, when applying the upper layer of the charge transport layer,
Depending on the solvent used, the charge transport layer force may easily cause crystallization. In the crystallized area, there is no optical attenuation, and the charge remains as a residual potential, which appears as a defect in image quality.

Secondly, a phenomenon called solvent cracking occurs in the bisphenol (A) polycarbonate resin depending on the solvent used when coating the upper layer. That is, when the charge transport layer once formed by coating is exposed again to another solvent, a phenomenon occurs in which the mechanical strength of the charge transport layer is significantly reduced. When such a photoreceptor belt is used and the belt is rotated for a long period of time in a copying machine for a long period of time, the charge transport layer cracks, which appears as a crack pattern on the copy.

[Purpose of the invention]

An object of the present invention is to provide an electrophotographic photoreceptor that does not have the disadvantages observed when such bisphenol (A) polycarbonate resins are used.

[Structure of the invention]

By using a copolycarbonate resin derived from bisphenol (A) represented by Structural Formula (1) and a dioxy compound represented by Structural Formula (If) as the binder polymer of the charge transport layer, the present inventors achieved the following: The inventors have discovered that these problems can be solved and have completed the present invention.

The present invention provides an electrophotographic photoreceptor comprising at least a charge generation layer and a charge transport layer, in which bisphenol (A) represented by Structural Formula (1) and bisphenol (A) represented by Structural Formula (n) are used as binder polymers in the charge transport layer. This is an electrophotographic photoreceptor characterized by using a copolycarbonate resin derived from a dioxy compound represented by:

In the structural formula II), x and x' represent a hydrogen atom, a halogen atom, or a methyl group, and R represents a hydrogen atom, a halogen atom, a hydroxyl group, a carboxyl group, an acetyl group, or a carbon number of 1 to
4 represents an alkyl group.

Generally, polycarbonate resin is a general term for polymers having a carbonate ester bond in the main chain of the molecule, and is represented by the general formula. For example, bisphenol (A)
The type of polycarbonate is the polycarbonate designated by.

The copolycarbonate according to the invention is a copolymer polycarbonate meeting the above definition.

The copolycarbonate of the present invention has structural formulas (I) and (If)
The compound is synthesized by appropriately applying the following known synthesis method, which is used in the synthesis of general polycarbonates.

(a) Reaction using phosgene (0) Reaction using bischloroformate of compounds (1) and (II) (c) Reaction using monochloroformate of compounds (I) and (n) (d) Reaction using carbonic acid diester Reaction to be used (e) Reaction using biscarbonate of compound (I) or (II) (f) Reaction using monocarbonate of compound (1) or (II) As a specific example of the dioxy compound represented by structural formula (II) may have the structure shown below.

COC horse Cj CnoB
r BrBr
ByCIH.

However, the compounds described above are examples and do not indicate all compounds of the structural formula (II) in the present invention, and all compounds satisfying the general formula of the structural formula ([) are applicable to the present invention. It is.

These bisphenol (A) of structural formula (1) and structural formula (
The copolymerization ratio of the dioxy compound in II) is 1:19 to 19:
A range of l: 1 is effective, more preferably l:9 to 4.
:1 is desirable. The molecular weight of this copolycarbonate is preferably 10,000 to 150,000.

It has also been found that when this copolycarbonate is used as a binder polymer for a charge transport layer, the crystallization resistance of the charge transport layer against solvents is significantly improved, and solvent cracks do not occur during coating of the upper layer. moreover,
The photoreceptor of the present invention using a copolycarbonate as the binder resin of the charge transport layer is made of ordinary bisphenol (A
), or an aromatic polycarbonate synthesized using a single compound of structural formula (II) as a raw material, as the binder resin of the charge transport layer. was also shown.

The electrophotographic photoreceptor of the present invention has at least a charge generation layer and a charge transport layer on the conductive layer, and even if the charge transport layer is laminated on the charge generation layer, the charge transport layer does not generate charge. The layers may be laminated. Further, a conductive or insulating protective layer may be formed on the surface layer as necessary. Furthermore, an adhesive layer to improve the adhesion between each layer,
Alternatively, an intermediate layer (blocking layer) or the like may be formed that serves to block charges.

The conductive substrate material used in this photoreceptor is a metal plate or sheet such as aluminum, brass, copper, nickel, or steel, and a conductive material such as aluminum, nickel, chromium, palladium, or graphite on a plastic sheet. It is possible to use materials that have been coated by vapor deposition, spackling, coating, etc. to make them conductive, or materials that have been made of glass, plastic plates, cloth, paper, etc. that have been subjected to conductive treatment.

Charge generating materials in the charge generating layer include amorphous selenium, trigonal selenium, zinc oxide, titanium oxide, selenium-tellurium alloy, ^5zse3, metal-free metal phthalocyanine, squareium pigment, anthracene, pyrene, perylene, pyrylium. Salts, cyanine, thiapyrylium salts, polyvinylcarbazole, etc. can be used.

Binder polymers in the charge generation layer include polystyrene, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl acecool, alkyd resin,
Known thermoplastic resins such as acrylic resin, polyacrylonitrile, polycarbonate, polyamide, polyketone, polyacrylamide, butyral resin, and polyester, and thermosetting resins such as polyurethane, epoxy resin, and phenolic resin are used.

Note that the copolycarbonate resin of the present invention may be used as the binder polymer of the charge generation layer.

The charge generation layer can be obtained by coating and drying a coating liquid in which the charge generation material described above is pulverized or dissolved in a solvent together with a binder polymer.

Charge transport materials in the charge transport layer include electron transport materials and hole transport materials.
Chloranil, bromoanil, tetracyanoethylene,
Tetracyanoquinodimethane, 2.4.7-) Lietro 9-fluorenone, 2.4,5.7-Tetranitro-9
- Electron-withdrawing substances such as fluorenone, 2.4.7-dolinitro-9-dicyanomethylenefluorenone, 2,4,5.7-titranitroxanthone, 2.4.9-)linitrothioxanthone, and these electron-withdrawing substances There are also polymerized products.

Examples of hole-transporting substances include torene, N-ethylcarbazole, N-isopropylcarbazole, N-methyl-N
-Phenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-10-ethylphenothiazine, N, N-diphenylhydrazino-3-methylidene-10-ethylphenoxazine, P-diethylaminobenzaldehyde-N, N-diphenylhydrazone, P
-Diethylaminobenzaldehyde = N-α-naphthyl-N-phenylhydrazone, P-pyrrolidinobenzaldehyde-N,N-diphenylhydrazone, 1,3.3-
1-dimethylindolenine-ω-aldehyde-N,N-
Hydrazones such as diphenylhydrazone, p-diethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone, 2,5-bis(p-diethylaminophenyl)-1,3,4-oxadiazole, l-phenyl- 3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrapurine, 1-(quinolyl(
21) -3-(p-diethylaminostyryl)-5-
(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2))-3-(p-diethylaminostyryl)
-5-(p=nidiethylaminophenylpyrazoline, l
-[6-Medoxypyridyl(2)) -3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-(pyridyl(5))-3-(
p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-(lepidil (2))
-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-(pyridyl(
2)) -3-(p-diethylaminostyryl)-4-
Methyl-5-(p-diethylaminophenyl)pyrazoline, 1-(pyridyl(2))-3-(α-methyl-p-
diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-phenyl-3-(p-diethylaminostyryl)-4-methyl-5-(p-diethylaminophenyl)pyrazoline, 1-phenyl-3-(
α-benzyl-p-diethylaminostyryl)-5-(
Pyrazolines such as p-diethylaminophenyl) pyrazoline and spiropyrazoline, 2-(p-diethylaminostyryl)-δ-diethylaminobenzoxazole,
2-(p-diethylaminophenyl)-4-(p-dimethylaminophenyl)-5-(2-chlorophenyl)
Oxazole compounds such as oxazole, thiazole compounds such as 2-(p-diethylaminostyryl)-6-dinithylaminobenzothiazole, triarylmethane compounds such as bis(4-diethylamino-2-methylphenyl)-phenylmethane , 1.1-bis(4-N, N
-diethylamino-2-methylphenyl)hebutane, 1
, 1.2.2-Tetrakis(4-N,N-dimethylamino-2-methylphenyl)ethane, etc., N,N-diphenyl-N,N'-bis(methylphenyl)benzidine, N , N'-diphenyl-N, N
'-bis(ethylphenyl)benzidine, N,N'-diphenyl-N, N'-bis(propylphenyl)benzidine, N,N'-diphenyl-N, N'-bis(butylphenyl)-benzidine, N, N'-bis(isopropylphenyl)-benzidine, N,N'-diphenyl-N
, N'-bis(secondary butylphenyl)-benzidine,
N,N'-diphenyl-N,N'-bis(tert-butylphenyl)-benzidine and N,N'-diphenyl-
Benzidine compounds such as N,N'-bis(chlorophenyl)-benzidine. Triphenylamine, poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinyl ataridine, poly-9-vinylphenylanthracene, pyrene-formaldehyde resin,
Examples include ethyl carbazole formaldehyde resin.

A charge transport layer can be formed by applying a coating solution in which these charge transport materials are dissolved together with the polycarbonate resin of the present invention and drying the coating solution.

Solvents that can be used in the coating solution for the charge generation layer and charge transport layer include aromatic hydrocarbons such as benzene, toluene, xylene, and chlorobenzene, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, methanol, ethanol, and isopropanol. alcohols such as ethyl acetate, esters such as methyl cellosolve, halogenated hydrocarbons such as carbon tetrachloride, carbon tetrabromide, chloroform, dichloromethane, ethers such as tetrahydrofuran, dioxane, and dimethylformamide and dimethyl sulfoxide.

Each layer is applied using an applicator, spray coater, bar coater, dip coater, dofter blade, or the like.

〔Example〕

The present invention will be explained in more detail below using examples. "Parts" are "parts by weight" unless otherwise specified.

Example 1 A copolycarbonate was synthesized using 10 parts of bisphenol (A) and IO part of a dioxy compound of compound (1).

2 parts of triphenylmethane represented by the following structural formula and the above copolycarbonate (molecular ff 168,000 ) 4 parts and 60 parts of dichloromethane
The coating liquid dissolved in the liquid was applied using a wire round rod and dried to form a charge transport layer with a thickness of 8 μm.

On top of this, a squareium pigment 2 represented by the following structural formula is added.
and 2 parts of polyester resin (Toyobo Pylon 200) are mixed in a mixed solution of 130 parts of dichloromethane and 130 parts of 1゜1.2-1-lichloroethane, and the mixture is pulverized with a ball mill and prepared for this application. The liquid was applied using a wire round rod and dried to form a charge generation layer with a thickness of about 1 μm.

- In this case, the charge transport layer did not crystallize during application of the charge generation layer. This photoreceptor was welded to create a belt-shaped photoreceptor, and the belt was continuously rotated while making copies using a heald module using a roll with a 2-inch radius. No cracks were found on the photoreceptor even when examined using a looper.

During this period, good image quality was also obtained.

Comparative Example 1 In the example, a charge transport layer was formed using bisphenol (A) polycarbonate (Macrolon 5705, 1.1 million molecules) as the binder polymer in the charge transport layer. When a charge generation layer was formed thereon under the same conditions as in Example 1, it was observed that crystals were generated in the charge transport layer.

Therefore, the amount of dichloromethane in the charge generation layer forming solution of Example 1 was changed to 260 parts, and the charge generation layer was coated and dried.

In this case, no crystallization of the charge transporting layer was observed. However, when this photoreceptor was processed into a belt shape by the method shown in Example 1 and continuously rotated, cracks appeared on the photoreceptor at 5KC, and a crack pattern appeared on the copy.

Example 2 Preparation of 2 parts of N,N'-diphenyl-N,N'-bis-(3methylphenyl)-(1,1'-biphenyl]-4,4' diamine, bisphenol (A) and various dioxy compounds Two parts of the copolycarbonate and 20 parts of dichloromethane were applied onto the AN sheet using an automatic applicator with a wet gap of 7 μm and dried to form a charge transport layer of 24 μm.

Bisphenol (A) was also used as a binder in the same manner.
) polycarbonate (molecular weight: 100,000) was used to form a charge transport layer. A portion of each sample was cut out and dichloromethane was sprayed onto the surface to perform a solvent treatment.

After these coating films were peeled off from the AN sheet, a rubbing resistance test was carried out using a folding tester (Toyosei 11: MITFd rolling fatigue tester) at a load of 1.5 kgW, and the folding resistance test was performed until the coating film was destroyed. The number of turns was calculated. The results are shown in Table 1.

Table 1 The present invention uses copolycarbonate resin, which is a first! tJ] Mechanical strength is higher than that of bisphenol (
A) It was shown that it was stronger than when polycarbonate was used and was less affected by solvent treatment. Further, a charge generation layer shown in Example 1 was formed by coating on these charge transport layers,
When the electrical characteristics were examined using 5p-428 manufactured by Kawaguchi Electric ■, they showed almost the same characteristics.

〔Effect of the invention〕

The electrophotographic window light material of the present invention does not cause crystallization in the charge transport layer or solvent crack phenomenon during its manufacture, and has high mechanical strength (and can be used by being attached to a copying machine). Provides stable image quality copies even for long periods of time.

Claims (1)

[Claims] In an electrophotographic photoreceptor comprising at least a charge generation layer and a charge transport layer, bisphenol (A) (I) represented by the structural formula (I) is used as a binder polymer for the charge transport layer.
▲There are mathematical formulas, chemical formulas, tables, etc.▼ ▼ Dioxy compound (II) represented by structural formula (II) Photoreceptor for electrophotography. However, in the structural formula (II), X and X' are a hydrogen atom, a halogen atom, or a methyl group, and R is a hydrogen atom, a halogen atom,
Hydroxyl group, carboxyl group, acetyl group or carbon number 1-4
represents an alkyl group.