JPH0531136B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a novel electrophotographic photosensitive material. More specifically, the present invention can be applied to, for example, an electrophotographic copying machine, a laser beam printer,
The present invention relates to an electrophotographic photosensitive material with high sensitivity and excellent durability, suitable for use in electrophotography such as CRT printers and electrophotographic plate making systems. Conventional technology Conventionally, photoconductive materials for electrophotographic photosensitive materials include inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc sulfide, polyvinyl carbazole,
Organic photoconductive materials such as oxadiazole and phthalocyanine are known. 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 conductive 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. It has given rise to sexuality. 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 subject to corona charging, toner phenomenon, etc.
Because electrical and mechanical external forces such as transfer to paper and cleaning processing are directly applied, durability against these forces is affected.Specifically, sensitivity and potential drop due to deterioration due to ozone generated during corona charging, and residual potential may be affected. Durability against surface abrasion and scratches caused by friction and friction is required. Therefore, various methods have been tried 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, in response to these demands, has high sensitivity and excellent durability against surface abrasion and scratches caused by rubbing, as well as repeated 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 As a result of intensive research to develop an electrophotographic photosensitive material using an organic photoconductive material with excellent sensitivity, durability, and electrical properties, the present inventors identified It has been discovered that the above object can be achieved by using a fluorine-containing polyetherketone resin having the structure, and based on this knowledge, the present invention has been completed. That is, the present invention provides an electrophotographic photosensitive material comprising a conductive substrate and a photosensitive layer provided thereon, in which a binder for at least one of a charge generating substance and a charge transporting substance constituting the photosensitive layer,
general formula (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 atom to which they are bonded, and X ₁ , X ₂ ,
X ₃ and X ₄ are hydrogen atoms or halogen atoms,
At least one of R ₁ , R ₂ , X ₁ , X ₂ , X ₃ and X ₄ is a fluorine atom or a fluorine-containing group,
When all of X ₁ , X ₂ , X ₃ and X ₄ are hydrogen atoms,
R ₁ and R ₂ are not both trifluoromethyl groups, and m is 0 or 1. It provides materials. 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 the above general formula (), and this repeating unit is
It may contain a species, or it may contain two or more species. The fluorine-containing polyetherketone resin used in the present invention has the general formula (X ₁ , X ₂ , X ₃ , X ₄ , R ₁ and R ₂ in the formula have the same meanings as above) and bisphenols represented by the general formula (In the formula, X is a halogen atom and m has the same meaning as above) in a thermally stable polar solvent in the presence of an alkali, preferably at 100 to 350°C. It can be produced by condensation polymerization at a temperature in the range of . Representative compounds of bisphenols represented by the general formula () are shown below. Moreover, as representative compounds of the aromatic dihalide represented by the general formula (), the following can be mentioned.

【formula】

【formula】

When producing the electrophotographic photosensitive material of the present invention, a metal such as aluminum or stainless steel, a cylindrical cylinder or film such as 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 0.05
It is about ~2μ. 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, quinocyanins, 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 electrotransport substance used in the photosensitive layer include pyrene, 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 or p-diethylaminobenzaldehyde-N,N-diphenylhydrazone, p-diethylaminobenzaldehyde-N-
α-Naphthyl-N-phenylhydrazone, p-pyrodinobenzaldehyde-N,N-diphenylhydrazone, 1,3,3-trimethylindolenine-ω-aldehyde-N,N-diphenylhydrazone, p-diethylbenzaldehyde -Hydrazones such as -3-methylbenzthiazolinone-2-hydrazone, 1-phenyl-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[quinolyl(2)] -3-(p
-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)
1-3-(p-diethylaminostyryl)-5-
(p-diethylaminophenyl)]pyrazoline, 1
-[6-methoxypyridyl(2)]-3-(p-diethylaminostyryl)-5-p-diethylaminophenylpyrazoline, 1-[pyridyl(3)]-3-(p-diethylaminophenylpyrazoline)
-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 2-(p-diethylaminostyryl)-6-diethylaminobenzoxazole, 2-(p-diethylaminophenyl)-4-(p- Oxazole and oxadiazole compounds such as dimethylaminophenyl)-5-(2-chlorophenyl)oxazole, 2,5-bis(p-diethylaminophenyl))-1,3,4-oxadiazole, 2-
Thiazole compounds such as (p-diethylaminostyryl)-6-diethylaminobenzthiazole, triarylmethane compounds such as bis(4-diethylamino-2-methylphenyl)phenylmethane, 1,1-bis(4-N,N-diethylamino -2-methylphenyl)heptane, 1,
Examples include polyarylalkanes such as 1,2,2-tetrakis(4-N,N-dimethylamino-2-methylphenyl)ethane;
A species may be used, or two or more species may be used in combination. The photosensitive layer in the electrophotographic photosensitive material of the present invention is
It may be composed of a single layer containing the charge generating material and the charge transporting material, or it may have a laminated structure of the charge generating material layer and the charge transporting material layer. When having such a laminated structure, there is no particular restriction on the lamination order of the charge transporting material layer and the charge generating material layer, and the charge transporting material layer may be provided on the charge generating material layer, or conversely, the charge transporting material layer may be provided on the charge generating material layer. A charge generation material layer may be provided on the transport 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. substance from 0.3 to
Homogenizer, ultrasonic, ball mill, vibrating ball mill, along with 10 times the amount of binder resin and solvent.
After thorough dispersion using a method such as a sand mill, attritor, or roll mill, this dispersion is applied onto the substrate coated with the barrier layer and dried to form a 0.02 to 1μ
A charge-generating substance layer is provided by forming a coating film of about 100%. 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 coating the same on the charge generation material layer. It is formed by 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, coating methods such as dip coating, spray coating, and spinner coating can be used, and drying is usually carried out at 10 to 200°C, preferably at 20°C.
It is desirable to perform drying with air or static drying at a temperature in the range of ~150°C for 5 minutes to 5 hours, preferably 10 minutes to 2 hours. The thickness of the produced 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 due to the strong electron-attracting property of fluorine atoms. it is conceivable that. In other words, it is presumed that the strong electron-attracting property of fluorine atoms causes localization of electrons, which strengthens the interaction between charge-generating substances and charge-transporting substances, making it easier for electrons and holes to move. be done. Effects of the Invention The photosensitive material for electrophotography of the present invention uses a fluorine-containing polyetherketone resin having a specific structure as a binder resin in the photosensitive layer, has high sensitivity, and has a surface that can be easily rubbed 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 Add 2 kg of sulfolane as a solvent to 1.0 mol of 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 1.0 mol of difluoroisophthalophenone, and 1.05 mol of potassium carbonate. After heating at 230°C for 2 hours with stirring to perform a polycondensation reaction, the resulting polymer was washed with water and reprecipitated to obtain the following white fluorine-containing polyetherketone (A). Ta. In addition, the following fluorine-containing polyetherketones (2) to (3) were produced by similar operations. Example 1 An 80φ x 400mm aluminum cylinder was used as a base, and copolymerized polyamide [manufactured by Toray Industries, Inc.]
A 5% by weight methanol solution of CM8000] was applied by dip coating to form a barrier layer with a thickness of 0.1μ. Next, chlorinated aluminum phthalocyanine pigment 1
Parts by weight and 100 parts by weight of chloroform were pulverized and mixed in a glass ball mill for 20 hours. A coating liquid was prepared by dissolving 1 part by weight of an acrylic resin [Acrydik A-801, manufactured by Dainippon Ink Co., Ltd.] into the obtained dispersion. This coating solution was dip-coated onto the barrier layer and dried by heating at 100° C. for 10 minutes to provide a charge-generating substance layer with a thickness of 0.03 μm. Next, p-diethylaminobenzaldehyde-
10 parts by weight of (diphenylhydrazone) and 10 parts by weight each of the fluorine-containing polyetherketone resins (a) to (h) obtained in Reference Examples were dissolved in 72 parts by weight of 1,2-dichloroethane. This solution was applied onto the charge generating material layer and dried with hot air at 100° C. for 1 hour to form a charge transporting material layer with a thickness of 20 μm. The photosensitive materials produced in this manner are referred to as Samples 1 to 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 containing no fluorine.
These will be referred to as Comparative Samples 1 and 2. Next, each of the above samples and comparative samples were tested, including a -5.5KV corona charging mechanism, an exposure mechanism using a semiconductor laser (790nm), 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. The dark potential (V _D ),
The potential during exposure (V _L ) was measured. The result is the first
Shown in the table.

[Table] The amount of wear in film thickness was 0.15μ for Sample 1 and 0.28μ for Comparative Sample 1. Example 2 Two ε-copper phthalocyanine pigments were used as photoconductors.
10 parts by weight of each of the above-mentioned fluorine-containing polyetherketones (a) and (b) and 60 parts by weight of dichloromethane were mixed in a sand mill using 1φ glass beads.
Spread out time. This dispersion was applied by dip coating onto a substrate coated with a barrier layer prepared in the same manner as in Example 1, and heated to 100°C.
The film was dried for 1 hour to form a 15 μm photoconductive layer. The photosensitive materials thus prepared are designated as Samples 9 and 10. For comparison, a photosensitive material was similarly prepared using Comparative Sample 1 as a polyetherketone resin containing no 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
A durability test was conducted on 10,000 sheets at room temperature and humidity, and the dark potential
V _D and exposure potential V _L were measured. The results are shown in Table 2.

[Table] Example 3 12 parts by weight of a pyrazoline compound with the following structural formula It was dissolved in 10 parts by weight of fluorine-containing polyetherketone (iii) and 60 parts by weight of dichloromethane. This solution was applied by dip coating onto a substrate coated with a barrier layer similar to that in Example 1, and dried at 100° C. for 1 hour to form a 15 μm thick charge transport material layer. Next, 10 parts by weight of the same chlorinated aluminum phthalocyanine pigment used in Example 1 was added to 100 parts by weight of a 10% dichloromethane solution of the polyetherketone (-3), and dispersed for 20 hours using a sand mill using glass beads. did. This solution was applied onto the charge transport material layer and dried at 100° C. for 20 minutes to form a charge generation material layer with a thickness of 4 μm. The prepared photosensitive material is referred to as Sample 11. Except for using fluorine-containing polyetherketone (d),
A photosensitive material was prepared in exactly the same manner. Sample 12
shall be. For comparison, a photosensitive material was similarly prepared using the polyetherketone containing no fluorine (comparative sample 1). This will be referred to as comparative sample 4. Next, each of the above samples and a comparative sample 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. A durability test of 30,000 sheets was carried out by attaching it to an electrophotographic laser printer at room temperature and humidity, and the dark potential (V _D ) and exposure potential (V _L ) were measured. The results are shown in Table 3.

【table】

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 (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 atom to which they are bonded, and X ₁ , X ₂ ,
X ₃ and X ₄ are hydrogen atoms or halogen atoms,
At least one of R ₁ , R ₂ , X ₁ , X ₂ , X ₃ and X ₄ is a fluorine atom or a fluorine-containing group,
When all of X ₁ , X ₂ , X ₃ and X ₄ are hydrogen atoms,
R ₁ and R ₂ are not both trifluoromethyl groups, and m is 0 or 1. Material. 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.