JPS63271270A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance image quality by reducing the content of an element of group Ia as an impurity in a specified fluororesin used for a protective layer to <=500ppm. CONSTITUTION:The resin of the protective layer of an electrophotographic sensitive body provided with an organic photoconductive layer on a conductive substrate contains the modified cross-linkable fluoresin soluble in organic solvents and represented by formula I in which R is OH or COOH and n is 20-100, or formula II in which R is alkyl, cycloalkyl, or the like, and X is halogen. Said fluororesin contains an element of group Ia in <=500ppm, and if over 500ppm, electrophotographic chracteristics and image quality are deteriorated, thus permitting the obtained electrophotographic sensitive body to be enhanced in electrophotographic characteristics.

Description

[Detailed description of the invention] [Industrial application field] This invention is the first step! The present invention relates to an electrophotographic photoreceptor provided with a layer.

[Conventional technology]

Conventionally, charge-generating materials for electrophotographic photoreceptors have been disclosed in Japanese Patent Application Laid-open No. 59
A large number of organic materials such as phthalocyanine-based pigments shown in Japanese Patent Publication No. 15253 and tellurium-arsenic-glassy selenium-based inorganic materials shown in Japanese Patent Publication No. 50-15137 have been proposed.

On the other hand, the charge transporting substance is a poly-N-vinylcarbazole type disclosed in JP-A No. 52-77730,
Various compounds such as pyrazoline derivatives shown in Japanese Patent No. 9-105537 have been proposed and have already been put into practical use as photoconductors for copying machines.

In recent years, a method of printing using an electrophotographic method using a laser as a type of high-speed printer has been devised. In particular, when a semiconductor laser is used as a light source, the light source section can be made extremely small.

Printers can be made smaller, power consumption can be significantly reduced, and printing can be performed at high speed. Furthermore, organic photoreceptors have the advantage that they can be disposed of by incineration after use.

However, when using an electrophotographic device based on the Carlson method, printing is performed through processes such as charging, exposure, development, transfer, fixing, and cleaning, but processes other than fixing are usually performed mainly on the photoreceptor. The photoreceptor receives electrical and chemical stimulation. Furthermore, in the development and cleaning steps, toner is electrostatically deposited on the photoreceptor, or excessive toner is removed from the photoreceptor, thereby causing mechanical stimulation.

Among these, chemical stimulation and mechanical stimulation particularly affect the life of the photoreceptor and print quality. Therefore, it is necessary to protect the photoconductor from these stimuli. For example, as described in Japanese Patent Laid-Open No. 130743/1983, a protective layer is provided on the surface of the photoconductor to protect it. ing.

On the other hand, one of the factors that adversely affects the print quality of printed matter is impurities in the electrophotographic photoreceptor. It is well known that inorganic photoreceptors improve the purity of photoconductive materials, as described in Japanese Patent Application Laid-Open No. 61-155506. However, regarding the highly insulating protective layer, there is no mention of impurities.

[Problem that the invention seeks to solve]

In an electrophotographic photoreceptor provided with a conventional protective layer.

There was a deficiency in which the residual potential increased and the image quality deteriorated.

An object of the present invention is to provide an electrophotographic photoreceptor capable of producing high-quality images.

[Means to solve problems]

The above object is achieved by controlling the content of elements of group a, which are impurities, in the resin for the protective layer to 500 ppm or less.

Organic pigments that generate charges include azoxybenzene, disazo, trisazo, benzimidazole, polycyclic quinone, indigoid, quinacridone, perylene, methine, α-type, and β-type.

Pigments that generate charges, such as metal-free types having various crystal structures such as γ-type, δ-type, ε-type, and di-type, or metal-type phthalocyanine-based pigments, can be used. These pigments are described, for example, in JP-A-47-37453 and JP-A-47-3754.
No. 4, JP-A-47-18543, JP-A-47-185
No. 44, JP-A No. 48-43942, JP-A No. 48-70
No. 538, JP-A-49-1231, JP-A-49-10
No. 5536, JP-A-50-75214, JP-A-53-
No. 44028.

It is disclosed in Japanese Patent Application Laid-open No. 17732/1983.

In particular, it is disclosed in Japanese Patent Laid-Open No. 182640/1982 and European Patent Publication No. 92255 in that it has sensitivity to long wavelengths (near 800 nm).

Gold metal phthalocyanines of the τ', η and η' types are preferred. In addition to these, any organic pigment that generates charge carriers upon irradiation with light can be used.

Charge transporting substances include poly-N-
Vinylcarbazole, halogenated poly N-vinylcarbazole, polyvinylpyrene, polyvinylindoquinoxaline, polyvinylbenzothiophene, polyvinylanthracene, polyvinylacridine, polyvinylpyrazoline, etc., and low molecular weight compounds such as fluorenone and fluorene.

2.7-sinitro 9-fluorenone, 4H-indeno(1,2,6)thiophen-4-one.

3.7-sinitrodibenzothiophene-5-oxide, 1-bromopyrene, 2-phenylpyrene, carbazole, 3-phenylcarbazole.

2-phenylindole, 2-phenylnaphthalene, oxadiazole, 1-phenyl-3-(4-diethylaminostyryl)-5-(4-diethylaminostyryl)
-5-(4-diethylaminophenyl)pyrazoline +2
(p-dimethylaminophenyl) -4-(p-
diethylaminophenyl)-5-(o-chlorophenyl)-1,3-oxazole, imidazole, chrysene,
Examples include tetraphenacrydene, triphenylamine, and derivatives thereof.

The charge generating substance can be used by being dispersed in a binder resin. Further, the film can also be formed by a vapor deposition method, a sputtering method, or the like, if necessary.

Further, the charge transport substance can be used by being dispersed or dissolved in the binder resin. It can also be used in combination with a charge generator if necessary. Furthermore, when either or both of the charge generating substance and the charge transporting substance are used as dispersed or compatible with the binder resin,
Additives such as a plasticizer, fluidity imparting agent, film-forming regulator, etc. can be added as necessary.

Further, there is no restriction at all to use two or more types of charge generating substances or charge transporting substances in combination.

The fluorine-containing copolymer used in the binder resin for the outermost layer of the present invention is chlorotriple oleoethylene.

Fluoroethylene and ethyl vinyl ether such as trifluoroethylene and tetrafluoroethylene.

Propyl vinyl ether, butyl vinyl ether.

Alkyl vinyl ether such as hexyl vinyl ether,
Alternatively, it is a copolymer of cycloalkyl vinyl ether such as cyclohexyl vinyl ether, and other components include hydroxyethyl vinyl ether and hydroxypropyl vinyl ether.

Hydroxy alkyl vinyl ethers such as hydroxybutyl vinyl ether, carboxyalkyl vinyl ethers such as carboxyethyl vinyl ether, ethylene, propylene, isobutylene, vinyl chloride, vinylidene chloride,
Vinyl acetate, vinyl n-butyrate, methyl methacrylate,
methacrylic acid.

It may also contain acrylic acid or the like as a copolymerization component.

The fluoroolefin is preferably contained in an amount of 40 to 60 mol% in the total amount of the above components.

Moreover, it is preferable to use alkyl vinyl ether and cycloalkyl vinyl ether in a total amount of 5 to 60 mol % based on the total amount of these components. If these are too small, it becomes difficult to dissolve in organic solvents, making it difficult to form a layer.

Furthermore, hydroxyalkyl vinyl ether and carboxyalkyl vinyl ether are included in the total amount of this component.
It is preferably 0 mol% or less, particularly 15 mol% or less. If this component is too large, the solubility in organic solvents will be poor.

The fluorine-containing copolymer of the present invention has a weight average molecular weight of 2,
000 to 20,000 (in terms of standard polystyrene in liquid chromatography) is preferable. If the molecular weight is too small, the film will be weak, and if it is too large, the viscosity will be high when dissolved in a solvent, making it difficult to form a single layer.

Unlike polyfluorinated ethylene, the fluorine-containing copolymer of the present invention is soluble in organic solvents such as xylene, toluene, butyl acetate, methyl isobutyl ketone, and alcohol, so that it is easy to form a layer.

The resin for the protective layer is composed of a modified cross-linked fluororesin or a resin that reacts with the modified cross-linked fluororesin and cures, and a reaction accelerator can be added if necessary.

Further, a charge-transporting substance such as a charge-transporting substance and/or a metal or a metal oxide can be incorporated into the protective layer.

In the protective layer of the electrophotographic photoreceptor of the present invention, by controlling the content of elements of group a, which are impurities, to 500 ppm or less, electrophotographic properties can be improved and image quality can be improved. When the amount of impurities exceeds 500 ppm, the electrophotographic properties deteriorate.

Reduce image quality.

To measure impurities, 30 g of fluororesin was placed in an autoclave (
After boiling at 120° C. and 5 atm), filtration was performed to extract the aqueous content, and the filtrate was concentrated and determined by atomic absorption spectrometry. Further, the fog density of the printed sample was determined using a Macbeth densitometer.

[Effect]

An electrophotographic photoreceptor has a photoconductive layer formed on a conductive support, and in recent years, functionally separated photoconductive layers in which a charge generation layer and a charge transport layer are formed separately have become mainstream. It has become. The generated charge moves both to the ground side and to the surface side of the photoreceptor. However, all of the generated charges are not transferred to both sides within a certain time, and a portion remains and is observed as a so-called residual potential.

As a result of extensive studies, the present inventors have found that the residual potential is largely related to impurities in the binder resin of the protective layer.By removing the impurities, the residual potential can be reduced and electrophotography with excellent image quality can be achieved. A photoreceptor was obtained.

〔Example〕

Examples 1 to 5 2 parts by weight of τ-type metal-free phthalocyanine (manufactured by Toyo Ink Co., Ltd.), silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd.).

KR5240) 13 parts by weight, dispersant (manufactured by Shin-Etsu Chemical Co., Ltd.).

A liquid consisting of 0.01 part by weight of KP323) and 85 parts by weight of tetrahydrofuran was kneaded for hours in a ball mill (manufactured by Nihon Kagaku Togyo Co., Ltd., 3-inch pot) to obtain a coating liquid for a charge generation layer. This coating liquid was applied onto an aluminum foil having a thickness of 100 μm using an automatic applicator and dried to obtain a charge generation layer. The thickness of this layer is approximately 1 μm. Polyester resin (Byron 200, Toyo Keisha 1) Log, 10 gy of oxazole compound (manufactured by Nippon Kanko Shiki Co., Ltd.), and 80 g of tetrahybarofuran were weighed into a glass container, stirred, and dissolved. The liquid was dropped onto the charge generation layer and cast to form a charge transport layer. The thickness of the dried membrane is 15 μm. A modified cross-linked fluororesin (LF-200, manufactured by M Glass Co., Ltd.) was purified through an ion exchange resin (Amberlyst 15, manufactured by Organo Co., Ltd.) to a total concentration of Na and K of 500,
450°260.50.15 ppm of fluororesin was obtained.

Five types of protective layer solutions having different Na concentrations were prepared, each consisting of 5 g of these fluororesin + 5 g of melamine resin and 100 g of isobutyl alcohol. Each of these five types of coating liquids was applied onto the charge transport layer and cured at 100''C, resulting in a film having a thickness of 0.5 μm.

The electrophotographic properties of an electrophotographic photoreceptor can be determined using an electrostatic recording paper tester (
The measurement was carried out using a model 5P-428 (manufactured by Kawaguchi Electric Co., Ltd.). The results are shown in Table 1.

Table 1 Comparative Examples 1 to 4 The charge generation layer and charge transport layer were produced under the same conditions as in Example 1. Next, the Na content is 550°600.800
．． 1000 ppm modified cross-linked fluororesin (LF-21
Two kinds of protective layer liquids were prepared, each consisting of 5 g of 0.m Glass Co., Ltd., 5 g of melamine resin, and 100 g of isobutyl alcohol.The protective layer liquid was coated on the charge transport layer and cured at 100°C. The thickness of the membrane is 0.5 μm. The results are shown in Table 2 (next page).

Table 2 [Effect of idea]

Claims (1)

[Scope of Claims] 1. In an electrophotographic photoreceptor having an organic photoconductive layer provided on a conductive support, the protective layer resin of the electrophotographic photoreceptor is a modified crosslinked resin having the following general formula and soluble in an organic solvent. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ Where, R; -OH, -COOH n; 20 to 100 or ▲There are mathematical formulas, chemical formulas, tables, etc.▼ Where, R; Alkyl group, Cycloalkyl group, hydroxyalkyl group, carboxyalkyl group . 2. The electrophotographic photoreceptor according to claim 1, wherein the protective layer resin is composed of the fluororesin alone or a resin that reacts and cures with the fluororesin.