JPH0549216B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an electrophotographic photoreceptor that can be widely used in electrophotographic application fields such as electrophotographic copying machines, laser beam printers, CRT printers, and electrophotographic plate making systems. Furthermore, the present invention relates to an electrophotographic photoreceptor having high sensitivity and excellent durability. [Prior Art] Inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have conventionally been used as photoconductive materials for electrophotographic photoreceptors. On the other hand, organic photoconductive materials such as polyvinylcarbazole, oxadiazole, and phthalocyanine have advantages over inorganic photoconductive materials, such as non-polluting properties and high productivity, but their low sensitivity has made it difficult to put them into practical use. However, in recent years, the development of various new organic photoconductive materials has progressed, and functionally separated photoreceptors in which a charge generation layer and a charge transport layer are laminated have appeared, making it possible to manufacture electrophotographic photoreceptors with practical sensitivity. However, in response to the increasing speed of hardware such as copying machines, electrophotographic photoreceptors with higher sensitivity are required. On the other hand, it goes without saying that electrophotographic photoreceptors 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 photoreceptors that can be used repeatedly, the surface layer of the photoreceptor, that is, the layer furthest from the substrate, is directly exposed to electrical and mechanical external forces such as corona charging, toner development, transfer to paper, and cleaning processing. Since these materials are added, durability against them is required. Specifically, it is required to have durability against a decrease in sensitivity, a decrease in potential, an increase in residual potential due to deterioration due to ozone generated during corona charging, and the occurrence of surface abrasion and scratches due to rubbing. Conventionally, various methods have been proposed to solve the above-mentioned drawbacks. As one such method, the use of polycarbonate resin as a binder for the surface layer is being considered. For polycarbonate resin,
Because of its good abrasion resistance, photoreceptors using polycarbonate resin as a binder in the surface layer have significantly improved durability against external mechanical forces. [Problems to be Solved by the Invention] An object of the present invention is to provide an electrophotographic photoreceptor that meets the above-mentioned requirements. That is, the first object of the present invention is to provide a highly sensitive electrophotographic photoreceptor. The second objective is to provide an electrophotographic photoreceptor that has durability against surface abrasion and scratches caused by rubbing. A third objective is to provide an electrophotographic photoreceptor that does not accumulate residual potential and can always produce high-quality images in repeated electrophotographic processes. [Means and effects for solving the problem] As a result of intensive research in accordance with the above purpose, the present inventor has discovered that
The present invention has been completed based on the discovery that an electrophotographic photoreceptor that meets the above requirements can be provided by using a fluorine atom-containing polycarbonate resin. That is, the present invention provides an electrophotographic photoreceptor comprising a photosensitive layer provided on a conductive substrate, characterized in that the photosensitive layer contains one or more types of fluorine atom-containing polycarbonate. It consists of a photographic photoreceptor. In the present invention, the fluorine atom-containing polycarbonate contains a repeating unit represented by the following general formula (1) as a constituent component. In the formula, at least one of R ₁ , R ₂ , X ₁ , X ₂ , X ₃ and X ₄ represents a fluorine atom and/or at least one substituent containing a fluorine atom.
Examples of the substituent containing a fluorine atom include an alkyl group, an aryl group, an alicyclic alkyl group, an alkoxy group, and R ₁ and R ₂ may form a cyclic structure together with the bonded carbon atoms. Furthermore, a halogen atom, a lower alkyl group, an aryl group, etc. may be substituted. R ₁ and R ₂ other than fluorine atoms and substituents containing fluorine atoms are hydrogen atoms, alkyl groups, aryl groups, etc., and R ₁ and R ₂ may form a cyclic structure together with the carbon atoms to which they are bonded. good. Furthermore, a halogen atom, a lower alkyl group, an aryl group, etc. may be substituted. X ₁ , X ₂ , X ₃ , and X ₄ other than fluorine atoms and substituents containing fluorine atoms are hydrogen atoms, halogen atoms other than fluorine atoms, alkyl groups, aryl groups, alicyclic alkyl groups, alkoxy base, etc.
It may further have a substituent. n is the degree of polymerization. The fluorine atom-containing polycarbonate resin in the present invention has one or more repeating units represented by the general formula (1) as constituent components, and can be used singly or as a blend. Further, the fluorine atom-containing polycarbonate resin in the present invention has R ₁ ,
A copolymer with a polycarbonate containing no fluorine atom in any of R ₂ , X ₁ , X ₂ , X ₃ , and X ₄ may be used. In the case of a copolymer, the fluorine atom-containing portion in the fluorine atom-containing polycarbonate resin is preferably 5 wt% or more, particularly 20 wt% or more. The fluorine atom-containing polycarbonate resin used in the present invention can be obtained by a general polycarbonate synthesis method such as the phosgene method using, for example, one or more bisphenols represented by the following general formula (2). be able to. In the formula, R ₁ , R ₂ , X ₁ , X ₂ , X ₃ and X ₄ have the same meanings as in the general formula (1). Next, typical examples of bisphenols represented by general formula (2) will be shown using structural formulas. When producing the electrophotographic photoreceptor 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 subbing layer (adhesive layer) having a barrier function and a subbing function can be provided on these substrates. The undercoat layer is formed to improve adhesion of the photosensitive layer, improve coating properties, protect the substrate, cover defects on the substrate, improve charge injection from the substrate, protect the photosensitive layer from electrical breakdown, etc. . The material for the undercoat layer is
Polyvinyl alcohol, poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, ethylene-acrylic acid copolymer, casein, polyamide, copolymerized nylon, glue, gelatin, and the like are known. These are each dissolved in a suitable solvent and applied onto the substrate. The film thickness is about 0.2 to 2μ. Examples of charge-generating substances include pyrylim dyes, thiapyrilim dyes, phthalocyanine dyes, anthanthrone pigments, dibenzpyrenequinone pigments, pyranthrone pigments, trisazo pigments, disazo pigments,
Azo pigments, indigo pigments, quinacridone pigments, asymmetric quinocyanines, quinocyanines, etc. can be used. As the charge transport substance, 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, p-diethylaminobenzaldehyde-N,N-diphenylhydrazone,
p-diethylaminobenzaldehyde-N-α-
Naphthyl-N-phenylhydrazone, p-pyrrolidinobenzaldehyde-N,N-diphenylhydrazone, 1,3,3-trimethylindolenine-
Hydrazones such as ω-aldehyde-N,N-diphenylhydrazone, p-diethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone, 2,5-bis(p-diethylaminophenyl)-1,3, 4-oxadiazole, 1-
Phenyl-3-(p-diethylaminostyryl)-
5-(p-diethylaminophenyl)pyrazoline,
1-[quinolyl(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)
Pyrazoline, 1-[pyridyl(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[6-methoxypyridyl(2)]-3-(p-diethylaminostyryl) )-5-(p-diethylaminophenylpyrazoline, 1-[pyridyl (3)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[lepidyl (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-
Pyrazolines such as p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline and spiropyrazoline, 2-(p-diethylaminostyryl)-6-diethylaminobenzoxazole, 2-(p-diethylaminophenyl)-4
-Oxazole compounds such as -(p-dimethylaminophenyl)-5-(2-chlorophenyl)oxazole, 2-(p-diethylaminostyryl)-
Thiazole compounds such as 6-diethylaminobenzthiazole, bis(4-diethylamino-2
-Triarylmethane compounds such as -methylphenyl)phenylmethane, 1,1-bis(4-N,
N-diethylamino-2-methylphenyl)heptane, 1,1,2,2-tetrakis(4-N,N
Low molecular weight charge transport materials such as polyarylalkanes such as -dimethylamino-2-methylphenyl)ethane can be used. The method for preparing the electrophotographic photoreceptor of the present invention will be explained using an example of a functionally separated photoreceptor in which a charge transport layer is laminated on a charge generation layer. The charge generating material is well dispersed with a binder resin and a solvent in an amount of 0.3 to 10 times using a homogenizer, ultrasonic wave, ball mill, vibrating ball mill, sand mill, attritor, roll mill, or the like.
This dispersion is applied onto the substrate coated with the subbing layer and dried to form a coating film with a thickness of about 0.1 to 1 μm. The charge transport layer is formed by dissolving the above-mentioned charge transport material in a solvent using the fluorine atom-containing polycarbonate of the present invention as a binder resin, and coating the solution on the charge generation layer. The mixing ratio of the charge transport material and the fluorine atom-containing polycarbonate is about 2:1 to 1:2. Solvents include aromatic hydrocarbons such as toluene and xylene, dichloromethane, chlorobenzene,
Chlorinated hydrocarbons such as chloroform and carbon tetrachloride are used. When applying this solution, coating methods such as dip coating, spray coating, spinner coating, bead coating, blade coating, and curtain coating can be used.
5 at a temperature in the range ~200℃, preferably 20-150℃
It can be carried out under air blow drying or stationary drying for a time of 10 minutes to 5 hours, preferably 10 minutes to 2 hours.
The thickness of the generated charge transport layer is approximately 5 to 20 μm. The reason why a highly sensitive photoreceptor can be obtained by containing the fluorine atom-containing polycarbonate of the present invention in a photosensitive layer is not clear, but it is thought to be due to the strong electron-attracting property of fluorine atoms. In other words, it is presumed that the strong electron-attracting property of the fluorine atom 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. be done. [Example] Synthesis of fluorine atom-containing polycarbonate The fluorine atom-containing polycarbonate used in the present invention is synthesized by reacting bisphenols represented by general formula (2) with phosgene. Specifically, 0.15 mol of bisphenols and 0.353 mol of phenol in a 500 ml separable flask with a stirrer.
g, 16.8 g of NaOH, and 238 ml of water. After heating and dissolving at 50°C, cool to 25°C and add 147ml of methylene chloride. Then phosgene was added with stirring at 25°C.
19.1 g is introduced over 60 minutes. Then, after adding 0.0342 g of trimethylbenzylammonium chloride, 4.5 g of NaOH, and 30 ml of water,
Polymerization is carried out for 4.5 hours with stirring at 25°C. After the polymerization is completed, dilute with 360 ml of methylene chloride, wash with hydrochloric acid to make it weakly acidic, and then wash with water 5 times. The polymer solution was poured into methanol and coagulated, separated and dried at 100°C and 1mmHg for 15 hours.
A white polymer is obtained. Example 1 An aluminum cylinder of 80φ x 300mm was used as a base, and polyamide (trade name Amilan CN-
8000 (manufactured by Toray Industries, Inc.) in 5% methanol was applied by dip coating to form a 1 μ thick subbing layer. Next, 10 parts of a disazo pigment with the following structural formula, 6 parts of cellulose acetate butyrate resin (trade name CAB-381, manufactured by Eastman Chemical) and cyclohexanone
60 parts with a sand mill using 1φ glass beads
Spread out time. Add methyl ethyl ketone to this dispersion.
Add 100 parts and apply by dip coating on the above subbing layer.
It was heated and dried at ℃ for 10 minutes to form a charge generation layer with a coating weight of 0.1 g/m ² . Next, 10 parts of a hydrazone compound having the following structural formula, 10 parts of each polycarbonate resin synthesized according to the polycarbonate synthesis method described above using each of the bisphenols of specific examples (1) to (24) of general formula (2) was dissolved in 55 parts of dichloromethane. Coat this solution on the above charge generation layer and heat it at 100°C.
A charge transport layer having a thickness of 18 μm was formed by drying with hot air for 1 hour. The produced photoreceptors are referred to as samples 1 to 24. For comparison, a photoreceptor similar to the above was prepared using a polycarbonate containing no fluorine (bisphenol A type polycarbonate, trade name Panlite L1250, manufactured by Teijin Kasei Ltd.), and this was designated as Comparative Sample 1. Next, each of the above samples and the comparative sample were attached to an electrophotographic copying machine equipped with a -5.5KV corona charger.
We conducted an empty charging durability test of 10,000 sheets under normal temperature and humidity.
Fluctuations in the V _D potential and the V _L potential were measured after exposure at 4.5 lux for seconds. The results are shown below.

[Table] 1
Furthermore, for each sample, -5.5KV corona charge,
Durability was evaluated for 10,000 sheets using an electrophotographic process consisting of image exposure, dry toner development, toner transfer to plain paper, and cleaning with a mag brush, and in all cases stable high-quality images could be obtained up to 10,000 sheets. was completed. Example 2 As a photoconductor, a fluorine atom-containing polycarbonate was synthesized using 2 parts of ε-copper phthalocyanine pigment and the bisphenols of specific example (2) of general formula (2) according to the synthesis method of the polycarbonate described above. 10 parts and 60 parts of dichloromethane were dispersed for 20 hours in a sand mill using 1φ glass beads. This dispersion was applied by dip coating onto a substrate coated with a subbing layer prepared in the same manner as in Example 1, and dried at 100° C. for 1 hour to form a 15 μm photoconductive layer. The prepared photoreceptor is designated as sample 25. A photoreceptor was prepared in exactly the same manner except that the bisphenols of specific example (16) of general formula (2) were used. This is designated as sample 26. For comparison, a photoreceptor was similarly prepared using a polycarbonate containing no fluorine (bisphenol A type polycarbonate, trade name: Iupilon S-2000, manufactured by Mitsubishi Gas Chemical Co., Ltd.). Comparative sample 2
shall be. Next, each of the above samples and the comparative sample were attached to an electrophotographic copying machine equipped with a +5.5KV corona charger.
We conducted an empty charging durability test of 10,000 sheets under normal temperature and humidity.
Fluctuations in the V _D potential and the V _L potential were measured after exposure at 4.5 lux for seconds. The results are shown below.

[Table] Furthermore, for each sample, +5.5KV corona charge,
Durability was evaluated for 10,000 sheets using an electrophotographic process consisting of image exposure, dry toner development, toner transfer to plain paper, and cleaning with a mag brush, and in all cases stable high-quality images could be obtained up to 10,000 sheets. was completed. Example 3 12 parts of a pyrazolone compound having the following structural formula, 10 parts of polycarbonate synthesized according to the polycarbonate synthesis method described above using the bisphenol of specific example (13) of general formula (2) was dissolved in 60 parts of dichloromethane. This solution was applied by dip coating onto a substrate coated with the same subbing layer as in Example 1, and dried at 100° C. for 1 hour to form a charge transport layer of 14 μm. Next, 10 parts of the same disazo pigment used in Example 1 was added to 100 parts of the 10 wt% dichloromethane solution of the polycarbonate, and dispersed for 20 hours using a sand mill using glass beads. This solution was applied onto the charge transport layer and dried at 100° C. for 20 minutes to form a charge generation layer with a thickness of 4 μm. The prepared photoreceptor is designated as sample 27. A photoreceptor was prepared in exactly the same manner except that the bisphenols of specific example (18) of general formula (2) were used. This is designated as sample 28. For comparison, a photoreceptor was similarly prepared using a polycarbonate containing no fluorine (bisphenol A type polycarbonate, trade name: Iupilon S-3000, manufactured by Mitsubishi Gas Chemical Co., Ltd.). Comparative sample 3
shall be. Next, each of the above samples and the comparative sample were attached to an electrophotographic copying machine equipped with a +5.5KV corona charger.
We conducted an empty charging durability test of 10,000 sheets under normal temperature and humidity.
Fluctuations in the V _D potential and the V _L potential exposed to light at 6.5 lux for seconds were measured. The results are shown below.

[Table] Furthermore, for each sample, +5.5KV corona charge,
Durability was evaluated for 10,000 sheets using an electrophotographic process consisting of image exposure, dry toner development, toner transfer to plain paper, and cleaning with a mag brush, and in all cases stable high-quality images could be obtained up to 10,000 sheets. was completed. [Effects of the Invention] The electrophotographic photoreceptor of the present invention has high sensitivity and excellent mechanical repetition durability. Furthermore, in repeated electrophotographic processes, residual charge accumulation is small, and high-quality images can always be obtained.

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor having a photosensitive layer provided on a conductive substrate, wherein the photosensitive layer contains one or more of a low molecular weight charge transport substance and a fluorine atom-containing polycarbonate. An electrophotographic photoreceptor characterized by: 2. The electrophotographic photoreceptor 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 layer has a laminated structure of a charge generation layer and a charge transport layer, and the charge generation layer and/or charge transport layer contains one or more fluorine atom-containing polycarbonates. An electrophotographic photoreceptor according to claim 1. 4. The electrophotographic photoreceptor according to claim 3, wherein the charge transport layer is provided on the charge generation layer. 5. The electrophotographic photoreceptor according to claim 3, wherein the charge generation layer is provided on the charge transport layer.