JPH01169456A - Electrophotographic sensitive material - Google Patents

Abstract

PURPOSE:To obtain the sensitive body having the excellent durability and the high sensitivity by using a specified fluorine-contg. polyether ketone resin as a binder at least one of an electric charge generating substance and an electric charge transfer substance which constitute a photosensitive layer. CONSTITUTION:The fluorine-contg. polyether ketone resin having a repeating unit shown by formula I is used as the binder at least one of the electric charge generating substance and the electric charge transfer substance which constitute the photosensitive layer. In formula I, R1 and R2 are each hydrogen or halogen atom, a hydrocarbon group or a halogenated hydrocarbon group, X1-X4 are each hydrogen or halogen atom, at least one of R1, R2, X1-X4 is fluorine atom or a group contg. a fluorine atom, and when the groups X1-X4 are all hydrogen atom, both groups R1 and R2 are not trifluoromethyl group, (m) is 0 or 1. Thus, the photosensitive body having the high sensitivity and the excellent durability against the generation of an abrasion and a flaw on the surface of the sensitive body caused by sliding and rubbing, is obtd.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a novel photosensitive material for electrophotography.

More specifically, the present invention relates to a sensitive material for electrophotography which has high sensitivity and excellent durability and is suitable for use in electrophotography such as electrophotographic copying machines, laser beam printers, CRT printers, and electrophotographic plate making systems. It is.

BACKGROUND ART Conventionally, as photoconductive materials for electrophotographic photosensitive materials, inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc sulfide, and organic photoconductive materials such as polyvinyl carbazole, oxadiazole, and phthalocyanine have been known. There is. Organic photoconductive materials generally have advantages over inorganic photoconductive materials, such as non-pollution and high productivity, but their low sensitivity has made them less practical, but in recent years various new organic photoconductive materials have been developed. As a result of the development of materials and functionally separated photosensitive materials in which a charge-generating material layer and a charge-transporting material layer are laminated, it is now possible to realize electrophotographic photosensitive materials with practical sensitivity using organic photoconductive materials. has occurred.

However, the sensitivity of such electrophotographic photosensitive materials is still not sufficient, and electrophotographic photosensitive materials with higher sensitivity are required in response to increasing speeds of hardware such as copying machines.

On the other hand, as a matter of course, electrophotographic photosensitive materials are required to have predetermined sensitivity, electrical properties, and optical properties depending on the electrophotographic process to which they are applied. In particular, in the case of photosensitive materials that can be used repeatedly, the surface layer of the photoreceptor, that is, the layer furthest from the substrate, is charged with corona.
Due to the direct application of electrical and mechanical external forces such as toner phenomenon, transfer to paper, and cleaning processing, durability against these forces is affected. Specifically, sensitivity and potential decrease due to deterioration due to ozone generated during corona charging. , durability against surface wear and scratches due to increased residual potential and abrasion is required.

Therefore, various methods have been attempted to overcome these drawbacks. For example, it has been proposed to use polycarbonate resin or polysulfone resin as a binder for the surface layer of the photosensitive layer, and since these resins have relatively good abrasion resistance, photoreceptors using such resins as the binder for the surface layer have been proposed. Although the durability against mechanical external forces has been considerably improved, it is still not sufficient, and there is a desire to develop a photoreceptor with even better durability and higher sensitivity.

Problems to be Solved by the Invention The present invention has been developed in response to these demands, has high sensitivity, excellent durability against surface abrasion and scratches caused by rubbing, and is capable of being repeatedly used for electrophotography. The purpose of this invention is to provide an electrophotographic photosensitive material that accumulates little residual potential during the process and always provides high-quality images.

Means for Solving the Problems The present inventors 1 have conducted intensive research to develop an electrophotographic photosensitive material using an organic photoconductive material with excellent sensitivity, durability, and electrical properties. By using fluorine-containing polyetherketone resin with a specific structure,
We have found a way to achieve the above object, and based on this knowledge, we have completed the present invention.

That is, the present invention provides an electrophotographic photosensitive material comprising a conductive substrate and a photosensitive layer provided thereon, in which at least one of a charge generating substance and a charge transporting substance constituting the photosensitive layer is used as a binder of the general formula %. Formula % (1) (R1 and R2 in the formula are a hydrogen atom, a halogen atom, a hydrocarbon group, or a halogenated hydrocarbon group, and R, and R2
and may form a cyclic structure together with the carbon atoms to which they are bonded, and X,,X,.

X3 and X are hydrogen atoms or halogen atoms, and Rl
, R2, X + , X! , X 3 and X, at least one of which is a fluorine atom or a fluorine-containing group;

When all of X, , X3 and X4 are hydrogen atoms, R1 and R1 cannot both be trifluoromethyl groups, and m
is 0 or 1) A fluorine-containing polyetherketone resin having a repeating unit represented by the following is provided.

The present invention will be explained in detail below.

The fluorine-containing polyetherketone resin of the present invention is composed of repeating units represented by formula (I) above, and may contain one type of repeating unit or two or more types of repeating units. It may contain.

Fluorine-containing polyetherketone Iit used in the present invention
Pilgrimage is, for example, a bisphenol represented by the formula - (X+, Xz, Xz, X, R+ and R2 in the formula have the same meanings as above) and , m has the same meaning as above) in a thermally stable polar solvent in the presence of an alkali, preferably 100%
It can be produced by polycondensation at a temperature in the range of ~350°C.

Representative compounds of bisphenols represented by the above-mentioned formula (n) are shown below.

F OF.

0/, CF, OH.

QF, O, F.

1'～. In addition, as representative compounds of the aromatic cybaride represented by the formula (I[[), the following can be mentioned.

When producing the electrophotographic photosensitive material of the present invention, a cylindrical cylinder or film made of metal such as aluminum or stainless steel, paper, or plastic is used as the substrate.

A barrier layer (adhesive layer) having a barrier function and a subbing function can be provided on these substrates.

The barrier layer is formed for the purpose of improving the adhesion of the photosensitive layer, improving the coating properties, protecting the substrate, covering defects on the substrate, improving charge injection from the substrate, protecting the photosensitive layer from electrical breakdown, and the like. Examples of materials used for this barrier layer include polyvinyl alcohol, poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, ethylene-acrylic acid copolymer, casein, polyamide, copolymerized nylon, glue, and gelatin.

These are usually dissolved in respective suitable solvents and applied onto the substrate. The film thickness is usually about 0.05 to 2 μm.

In the present invention, charge generating substances used in the photosensitive layer include, for example, pyrylium dyes, thiapyrylium dyes, phthalocyanine pigments, anthantrone pigments, dibenzpyrenequinone pigments, pyranthrone pigments, trisazo pigments, disazo pigments, azo pigments, Indigo pigments, quinacridone pigments, asymmetric quinocyanines, quinocyanines, etc. may be used, and one type of these may be used, or two or more types may be used in combination.

In the present invention, examples of the electrotransporting substance used in the photosensitive layer include methane, N-ethylcarbazole, N-ingrovir-rubazole, N-methyl-N-7enylhydrazino, 3-methylidene-9-ethylcarbazole, and Methylidene-9/ethylcarbazole, N,N-diphenylhydrazino/3-methylidene-10-ethylphenothiazine, N,N-diphenylhydrazino/3-methylidene/10-ethylphenoxazine or p-diethylaminobenzaldehyde-N,N -diphenylhydrazone, p-diethylaminobenzaldehyde-N-
σ-su7thi-N phenylhydrazone, p-pyrodinobenzaldehyde-N,N-diphenylhydrazone, 1
, 3. Hydrazones such as 3-1-limethylindolenine-ω-aldehyde-N,N-diphenylhydrazone, p-diethylbenzaldehydonzthiazolinone-2-hydrazone, l-phenyl-3-(p-diethylamino Styril)
-5.(p-diethylaminophenyl)pyrazoline, 1
(quinolyl(2))-3・(p-diethylaminostyryl) 5-(p-diethylaminophenyl)pyrazoline, l-(pyridyl(2)1-3-(p-diethylaminostyryl)-5(p-diethylaminophenyl) ] Pyrazoline, 1-(6-medoxypyridyl(2))-3-(
p-diethylaminostyryl)-5・p-diethylaminophenylpyrazoline, 1・(pyridyl(1))-3-
Pyrazolines such as (p-diethylaminostyryl)5-(p-diethylaminophenyl)pyrazoline, 2-(
p-diethylaminostyryl)-6-diethylaminobenzoxasol, i(p-diethylaminophenyl)
-4-(p-dimethylaminophenyl)-5-(
2-70 phenyl)oxazole, 2,5-bis(p
-diethylaminophenyl))-1.3.4-oxadiazole and other oxazole and oxadiazole compounds; 2-(p-diethylaminostyryl)-〇-diethylaminobenzthiazole and other thiazole compounds;
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. Examples include polyarylalkanes such as N-dimethylamino-2.methylphenyl)ethane, which may be used alone or in combination of two or more.

The photosensitive layer in the electrophotographic photosensitive material of the present invention may be composed of a single layer containing the charge generating substance and the charge transporting substance, or may have a laminated structure of the charge generating substance layer and the charge transporting substance layer. may have.

In the case of having such a laminated structure, there is no particular restriction on the lamination order of the charge transport material layer and the charge generation material layer, and the charge transport material layer may be provided on the charge generation material layer.
Conversely, a charge generating material layer may be provided on the charge transporting material layer.

The electrophotographic photosensitive material of the present invention is characterized in that the above-mentioned fluorine-containing polyetherketone resin is used as a binder in the photosensitive layer, and one type of the fluorine-containing polyetherketone resin may be used. However, two or more types may be used in combination. Further, when the photosensitive layer has a laminated structure consisting of a charge generating material layer and a charge transporting material layer, the fluorine-containing polyetherketone resin may be contained in the charge generating material layer or may be contained in the charge transporting material layer. or may be contained in both.

Next, a preferred method for preparing the electrophotographic photosensitive material of the present invention will be explained using an example of a functionally separated photosensitive material in which a charge transporting material layer is laminated on a charge generating material layer. The substance is mixed with 0.3 to 10 times the amount of binder resin and solvent using a homogenizer, ultrasonic wave, ball mill,
After well dispersing using a method such as a vibrating ball mill, sand mill, attritor, or roll mill, this dispersion is applied onto the substrate coated with the barrier layer and dried.
A charge generating material layer is provided by forming a coating film of about 1 μm.

The charge transport material layer is formed by dissolving the above charge transport material in a solvent using the fluorine-containing polyetherketone resin according to the present invention as a binder resin, and applying the resulting solution onto the charge generation material layer. It is formed.

The ratio of the charge transport material to the fluorine-containing polyetherketone resin is usually selected in the range of 2:1 to 1:2 based on weight.

As the solvent, aromatic hydrocarbons such as toluene and xylene, chlorine hydrocarbons such as dichloromethane, chlorobenzene, chloroform, and carbon tetrachloride are used.゛When applying the solution, a coating method such as a dip coach ink method, a spray coating method, or a spinner coating method can be used. It is desirable to carry out the drying at a temperature of about 5 minutes to 5 hours, preferably about 10 minutes to 2 hours, under air blow drying or stationary drying. The thickness of the generated charge transport material layer is preferably about 5 to 20 microns.

The reason why a highly sensitive photoreceptor can be obtained by containing the fluorine-containing polyetherketone resin according to the present invention in a photosensitive layer is not necessarily clear, but it is believed that it is due to the strong electron-attracting property of fluorine atoms. Conceivable.

In other words, it is presumed that the strong electron-attracting property of fluorine atoms causes localization of electrons, which strengthens the interaction with charge-generating substances and charge-transporting substances, making it easier for electrons and holes to move. .

Effects of the Invention The electrophotographic photosensitive material of the present invention uses a fluorine-containing polyetherketone resin having a specific structure as a binder resin in the photosensitive layer, and is highly sensitive and has a surface that can be easily removed by rubbing. In addition to being durable against abrasion and scratches, it also has excellent features such as little accumulation of residual potential during repeated electrophotographic processes, and high-quality images can always be obtained.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

Reference example Production of fluorine-containing polyetherketone resin 2.2
・Bis(4-hydroxyphenyl)hexafluoropropane 1.0 mol, difluoroin 7talophenone 1.0
Add sulfolane 2 to 9 as a solvent to 1.05 mol of potassium carbonate, heat at 230°C for 2 hours while stirring to perform a polycondensation reaction, and then wash the resulting polymer with water and reprecipitate. As a result, a white fluorine-containing polyetherketone (a) shown below was obtained.

I; By similar operations, the following fluorine-containing polyetherketones (b) to (h) were produced.

Repeating unit Reduced viscosity Example 1 An aluminum cylinder of 80dX400++v+ is used as a base, and copolymerized polyamide [Toshishiku Co., Ltd.] gaCM is applied to this.
Apply a 5 wt% methanol solution of SOOO) by dipping,
A barrier layer with a thickness of 0.1 μm was provided.

Next, 1 part by weight of chlorinated aluminum phthalocyanine pigment,
100 parts by weight of chloroform was mixed with 2 parts by weight in a glass ball mill.
The mixture was ground and mixed for 0 hours. Acrylic resin [Acridic A-10+] was added to the obtained dispersion.

1 part by weight (manufactured by Dainippon Ink Co., Ltd.) was dissolved to prepare a coating liquid. This coating solution was applied by dipping onto the barrier layer, and
The film was dried by heating at 0° C. for 10 minutes to form a charge generating material layer having a thickness of 0.03 μm.

Next, 10 parts by weight of p-diethylaminobenzaldehyde (diphenylhydrazone) and 10 parts of each of the fluorine-containing polyether ketone resins (a) to (h) obtained in the reference example were added.
Parts by weight were dissolved in 72 parts by weight of 1,2-dichloroethane. This solution is applied onto the charge generating material layer, and 111
A charge transport material layer having a thickness of 20 μm was formed by drying with hot air at 0° C. for 1 hour. Samples 1 to 1 of the photosensitive materials prepared in this way
8.

For comparison, a photosensitive material was prepared in the same manner as above using a polyetherketone resin having the following structural formula as a polyetherketone resin that does not contain fluorine.

This is designated as comparative sample 1.2.

(Comparative sample 1) (Comparative sample 2) Next, each of the above samples and the comparative sample were heated using a -5.5 KV corona charging mechanism, an exposure mechanism using a semiconductor laser (790 am),
Dry toner reversal development mechanism, toner transfer mechanism to plain paper,
A durability test of 1,100 sheets was conducted at room temperature and humidity by attaching it to an electrophotographic laser printer equipped with a cleaning mechanism using a urethane rubber blade and a static elimination exposure mechanism, etc., and the dark potential (VO) and exposure potential (VL) was measured.

The results are shown in Table 1.

Table 1 8. The wear amount of the film thickness is 0.15 μ for sample 1, and comparative sample 1.
was 0.28μ.

Example 2 2 parts by weight of e-copper phthalocyanine pigment as a photoconductor;
Each of the above-mentioned fluorine-containing polyetherketones (a) and (b) is 101! [11 parts by weight and 60 parts by weight of dichloromethane were dispersed for 20 hours in a sand mill using II glass beads.

This dispersion was dip-coated onto a substrate coated with a barrier layer prepared in the same manner as in Example 1, and was coated with Zo.

It was dried for 1 hour at 0.degree. C. to form a 15 micron photoconductive layer.

The photosensitive material prepared in this manner is named Sample 9.10.

For comparison, a photosensitive material was prepared in the same manner using Comparative Sample 1 as a polyetherketone resin that does not contain fluorine. This will be referred to as comparative sample 3.

Next, each sample and the comparative sample were attached to an electrophotographic copying machine equipped with a +5.5KV corona charger, and durability tests were conducted on Iff and Goo sheets at room temperature and humidity, and the dark potential (To)
In addition, the exposure potential (VL) was measured. The results are shown in Table 2.

Table 2 Example 3 12 parts by weight of a pyrazoline compound having the following structural formula were dissolved in 10 parts by weight of fluorine-containing polyetherketone (c) and 60 parts by weight of dichloromethane. This solution was applied by dip coating onto a substrate coated with the same barrier layer as in Example 1, and heated at 100°C for 1 hour.
A 15 micron layer of charge transport material was formed by drying for a period of time.

Next, 10 parts by weight of the same chlorinated aluminum phthalocyanine pigment used in Example 1 was added to the polyetherketone (f
It was added to 100 parts by weight of a 10% by weight dichloromethane solution of f-3) and dispersed for 20 hours in a sand mill using glass beads.

This solution was pushed up and applied onto the charge transport material layer, and
It was dried at .degree. C. for 20 minutes to form a charge generating material layer with a thickness of 4 .mu.m. The prepared photosensitive material is referred to as Sample 11.

A photosensitive material was prepared in exactly the same manner except that fluorine-containing polyetherketone (d) was used. This is designated as sample 12.

For comparison, a photosensitive material was similarly prepared using the above-mentioned fluorine-free polyetherketone (Comparative Sample 1).

This will be referred to as comparative sample 4.

Next, each of the above samples and comparative samples were equipped with a +5.6KV corona charging mechanism, an exposure mechanism using a semiconductor laser, a dry toner reversal development mechanism, a toner transfer mechanism to plain paper, a cleaning mechanism using a urethane rubber blade, and a static elimination exposure mechanism. Attach it to an electrophotographic laser printer and store it at room temperature and humidity for 30 minutes. An durability test was conducted on the OH sheet, and the dark potential (VD
), and the potential upon exposure (VL) was measured. The results are shown in Table 3.

Table 3

Claims (1)

[Scope of Claims] 1. In an electrophotographic photosensitive material comprising a conductive substrate and a photosensitive layer provided thereon, as a binder for at least one of a charge generating substance and a charge transporting substance constituting the photosensitive layer, a compound of the general formula ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (R_1 and R_2 in the formula are hydrogen atoms, halogen atoms,
A hydrocarbon group or a halogenated hydrocarbon group, R_1
and R_2 may form a cyclic structure together with the carbon atoms to which they are bonded, and X_1, X_2, X_
3 and X_4 are hydrogen atoms or halogen atoms, R_
1. At least one of R_2, X_1, X_2, X_3, and X_4 is a fluorine atom or a fluorine-containing group, but if all of X_1, 1. A photosensitive material for electrophotography, characterized in that it uses a fluorine-containing polyetherketone resin having a repeating unit represented by: 2. The photosensitive material for electrophotography according to claim 1, wherein the photosensitive layer is a single layer containing a charge generating substance and a charge transporting substance. 3. The photosensitive material for electrophotography according to claim 1, wherein the photosensitive layer has a laminated structure of a charge generating material layer and a charge transporting material layer. 4. The photosensitive material for electrophotography according to claim 3, wherein the photosensitive layer has a charge transporting material layer provided on a charge generating material layer. 5. The photosensitive material for electrophotography according to claim 3, wherein the photosensitive layer has a charge-generating material layer provided on a charge-transporting material layer.