JPH02232658A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To inhibit the lowering of potential by electrification at the time of repeated use by incorporating a 2,2,6,6-tetramethyl-1-piperidinyloxy deriv. into a photosensitive layer. CONSTITUTION:A 2,2,6,6-tetramethyl-1-piperidinyloxy deriv. (TEMPO deriv.) is incorporated into a photosensitive layer. Since the TEMPO deriv. is chemically adsorbed on an electric charge generating material and an electric charge transferring material, the trapping of electric charges generated by light absorption in the photosensitive layer is inhibited and the electric charges are rapidly transferred or recombined. The TEMPO deriv. used may be TEMPO, 4-amino- TEMPO, 4-(ethoxyfluorophosphinyloxy)-TEMPO, 4-hydroxy-TEMPO, 4- isothiocyanato-TEMPO, 4-maleimido-TEMPO, 4-(4-nitrobenzoyloxy)-TEMPO or 4-oxo-TEMPO, etc. The lowering of potential by electrification at the time of repeated use is inhibited.

Description

[Detailed Description of the Invention] [Industrial Field] The present invention relates to an electrophotographic photoreceptor, and more specifically, an electrophotographic photoreceptor that exhibits good sensitivity, excellent environmental resistance, and excellent durability. Regarding photoreceptors. [Prior Art] Inorganic materials such as selenium, cadmium sulfide, and zinc oxide have been conventionally known as photoconductive materials for electrophotographic photoreceptors. However, these inorganic materials do not necessarily satisfy the characteristics such as photosensitivity, thermal stability, and durability required for electrophotographic photoreceptors, as well as the manufacturing conditions. For example, selenium tends to crystallize due to heat, dirt, etc., and its properties tend to deteriorate. In addition, it has drawbacks such as manufacturing cost, impact resistance, toxicity, and other issues that require careful handling. Photoreceptors using cadmium sulfide have poor moisture resistance and durability, and are also susceptible to toxicity. Zinc oxide also has the disadvantage of poor moisture resistance and durability. In contrast to electrophotographic photoreceptors using these inorganic photoconductive materials, photoreceptors using organic photoconductive materials are being actively researched due to their light weight, ease of film formation, manufacturing cost, and wide variation as organic compounds. Development is underway. For example, in the early stages, photoreceptors containing polyvinyl-rubazole and 2,4,7-trinitro-9-fluorenone as described in Japanese Patent Publication No. 50-10496, and polyvinyl-rubazole as described in Japanese Patent Publication No. 48-25658 as biryllium salts. Photoreceptors sensitized with dyes or photoreceptors mainly composed of eutectic complexes have been proposed. However, these photoreceptors do not have sufficient sensitivity and durability. Therefore, in recent years, a functionally separated photoreceptor in which the charge generation layer and charge transport layer are separated has been proposed.
A photoreceptor comprising a combination of chlordiane blue and a hydrazone compound described in Japanese Patent Publication No. 55-42380, and a bisazo compound used as a charge generating substance in Japanese Patent Publication No. 53-1334.
45, JP-A No. 54-21728,
JP-A-58-198043 and JP-A-58-19935 are described as charge transport materials.
Those listed as 2nd place are known. However, even these function-separated photoconductors are not satisfactory, especially in terms of durability.In recent years, as demands for durability have increased more and more, ensuring charging stability has become an issue that cannot be ignored. ．． In other words, if the charging property decreases, the image density of the copy will decrease in the copier.
Laser printers that use a reversal development method cause deterioration in image quality, such as background stains.
In order to solve these problems. It has been proposed to provide an intermediate layer between the conductive substrate and the photosensitive layer. However, if a high-resistance material with high barrier properties is used for the intermediate layer in order to stabilize the charging property, although the charging property will be improved, the drawbacks are that the photosensitivity will decrease and the residual potential will increase. Furthermore, if a material with relatively low resistance that does not increase the residual potential is used, charging stability will be insufficient. On the other hand, when a photoreceptor is actually used in a copying machine, it is exposed to ozone generated from a charger, so
The addition of an antioxidant to the photosensitive layer has been proposed as seen in Japanese Patent Application Laid-open Nos. 122444-122444, 156052-1982, 39863-1986, and 73255-1983. However, most antioxidants have only a small effect on charge stability, and even those that are effective have side effects such as increased residual potential. [Problems to be Solved by the Invention] The present invention provides an electrophotographic photoreceptor whose charging potential does not decrease even during repeated copying processes by incorporating a substance in the photoreceptor that is extremely effective in increasing the durability of the photoreceptor. The purpose is to provide the following. [Means for Solving the Problems] According to the present invention, in an electrophotographic photoreceptor in which a photosensitive layer containing at least a charge-generating substance and a charge-transporting substance is provided on a conductive support, two .2,6,6-tetramethyl-1-piperidinyloxy derivative (hereinafter referred to as T
Provided is an electrophotographic photoreceptor characterized by containing an EMPO derivative (EMPO derivative). Since the electrophotographic photoreceptor of the present invention contains a TEMPO derivative in the photosensitive layer,
In addition to being highly sensitive, it has the advantage that the charging potential does not decrease even when the copying process of charging and exposure is repeated. Ding EMPO! The reason why It conductors have such effects is not clear at present, but it is believed that TENPO derivatives are chemically adsorbed to charge-generating and charge-transporting substances.
This is thought to be due to the fact that charges generated by light absorption are prevented from being trapped in the photosensitive layer, and are quickly moved or recombined, thereby suppressing the decrease in charging potential during repeated use. It will be done. Specific examples of TEMPO derivatives used in the present invention include Teha, Tatoeba, TEMPO, 4-7 Mi/-TEMPO,
4-(ethoxyfluorophosphinyloxy)-TEMP
0, 4-HiF Mouth? r C-TEMP0. 4-Isophyt Cy7neh-TEMP0.4-Maleimido T
EMP0. 4-(4-nitropenzoyloxy)-TE
Examples include MPO, 4-, t-ki'/-TEMPO, etc., but the larel is not limited to these. As the charge generating substance applied to the present invention, any inorganic pigment or organic dye can be used as long as it absorbs visible light and laser light and generates free charges. Examples of organic dyes and pigments include: (1) Berylene pigments such as berylene anhydride and berylene ugly imide. (2) Indigo pigment. (3) Quinacridone pigment. (4) Polycyclic quinones such as anthraquinones, bilenequinones, anthorthros, and flavanthrones. (5) Bisbenzimidazole *a. (6) Square methine pigment. (7) Indathlon pigment. (8) Phthalocyanine pigments such as metal phthalocyanines and metal-free phthalocyanines. (9) Monoazo pigment. Azo pigments such as disazo pigments and triazo pigments. Examples of monoazo pigments include azo pigments having a central skeleton of anthraquinone, N-phenylcarbazole, etc., and examples of disazo pigments include benzidine-based materials such as Diane Blue Chlor Diane Blue. Or, N-ethylcanolebazonole, stynoleben, distylbenzene, naphthalene, fluorenone, fluorene, anthraquinone, 2,5-diphenyl-1.3.4-oxadiazole, dibenzothiophene, dibenzothiophene dioxide, acridone, There are disazo materials having a central skeleton such as phenanthrenequinone and diphenylamine. Examples of trisazo pigments include trisazo pigments having a central skeleton such as triphenylamine or N-phenylcarbazole. (10) Azulenium salt compound (l1) Quinoneimine pigments such as azine pigments, oxazine pigments, and thiazine pigments. (12) Verinone pigments such as bisbenzimidazole derivatives. In addition, in the present invention, a charge transport material is used together with a charge generation material, and the charge transport material includes a hole transport material and an electron transport material. Examples of the hole transport substance include compounds represented by the following general formulas (1) to (13). K1 [wherein RL represents a methyl group, ethyl group, 2-hydroxyethyl group or 2-chloroethyl group, R8 represents a methyl group, ethyl group, benzyl group or phenyl group, R
J represents hydrogen, chlorine, bromine, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, a dialkylamino group, or a nitro group. ] K [in the formula. Ar represents naphthalenes, anthracenes, styryl groups and substituted products thereof, pyridines, furans, and thiophenes, and R represents an alkyl group or a benzyl group. ] K1 [wherein R1 is an alkyl group, benzyl group, phenyl group,
Represents naphthyl group. R2 represents hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a dialkylamino group, a dialkylamino group, or a diarylamino group, n represents an integer of 1 to 4, and n is 2 In the above cases, h may be the same or different. R1 represents hydrogen or a methoxy group. 1? In the formula, R, has a carbon number of 1 to 1
1 represents an alkyl group, a substituted or unsubstituted phenyl group, or a heterocyclic group, and R and R3 may be the same or different, respectively, hydrogen, an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group. Chloroalkyl group, W substituted or no W1
R2 and R may be bonded to each other to form a nitrogen-containing heterocycle. R4 may be the same or different and represents hydrogen, an alkyl group having 1 to 4 carbon atoms, an alkoxy group, or a halogen. [In the formula, R represents hydrogen or a halogen atom, and Ar represents a substituted or unsubstituted phenyl group, naphthyl group, anthryl group, or carbazolyl group. ] [In the formula, H1
represents hydrogen, halogen, cyano group, alkoxy group having 1 to 4 carbon atoms, or alkyl group having 1 to 4 carbon atoms. Ar
R1 represents an alkyl group having 1 to 4 carbon atoms, R,,R
, represents hydrogen, halogen, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a dialkylamino group, and n is 1 or 2, and when n is 2, R may be the same. May be different, R. and R represents hydrogen, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted benzyl group. [In the formula, R is a carbazolyl group, pyridine group, chenyl group, indolyl group, furyl group, or a substituted or unsubstituted phenyl group, styryl group, naphthyl group, or anthryl group, and these substituents are dialkylamino groups , alkyl group, alkoxy group, carboxy group or ester thereof, halogen atom, cyano group, aralkylamino group, toalkyl N-
Represents a group selected from the group consisting of an aralkylamino group, an amino group, a nitro group, and an acetylamino group. [In the formula, R represents a lower alkyl group, a benzyl group, or a substituted or unsubstituted aryl group, and R2 represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a halogen atom, a nitro group, an amino group, or a lower alkyl group. represents an amino group substituted with a group or a benzyl group, and n represents an integer of 1 or 2. [In the formula, R represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom, and R2
and R3 represents an alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group;
4 represents a hydrogen atom or a substituted or unsubstituted phenyl group, and ^r represents a phenyl group or a naphthyl group. ] represents a 9-anthryl group or a substituted or unsubstituted N-alkylcarbazolyl group, where R4 is a hydrogen atom,
Alkyl group, alkoxy group, halogen atom alkyl group,
represents a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, R and R6 may form a ring), m is wl& of 0, 1, 2 or 3, and When is 2 or more, R may be the same or different. [In the formula, n is an integer of 0 or 1, R21R3 represents a hydrogen atom, an alkyl group, an alkoxy group, or a substituted or unsubstituted phenyl group, and ^ is a R represents hydrogen, a lower alkyl group, a lower alkoxy group, a dialkylamino group or a halogen atom, and n represents O or l. ] [In the formula,
R represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom, and R,,R, may be the same or different and represent a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom. ] Kl [In the formula, R1 and R2 may be the same or different and represent a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom. R3 represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom. ] The compound represented by the general formula (1) includes, for example, 9-ethyl-rubazol-3-aldehyde-1-methyl-1-
Phenylhydrazone, 9-Ethyl Rubazole-3-Anoledehyde-1-Phenylhydrazone, 9-Ethyl Rubazole-3-Aldehyde-1.1
-Diphenylhydrazone, etc. Examples of the compound represented by the general formula (2) include 4-diethylaminostyrene-β-aldehyde-1-methyl-
1-phenylhydrazone, 4-methoxynaphthalene-l
-Aldehyde-1-benzyl-1-phenylhydrazone, etc. Examples of the compound represented by the general formula (3) include 4-methoxybenzaldehyde-1-methyl-1-phenylhydrazone, 2,4-dimethoxybenzaldehyde-1-
Benzyl-1-phenylhydrazone, 4-diethylaminobenzaldehyde-1,I-diphenylhydrazone.
4-Methoxybenzaldehyde-1-benzyl-1-(
4-methoxy)phenylhydrazone, 4-diphenylaminobenzaldehyde-1-benzyl-1-phenylhydrazone, 4-dibenzylaminobenzaldehyde
, 1-diphenylhydrazone, etc. General formula (4)
Examples of compounds represented by include l,1-bis(4-
dibenzylaminophenyl) pronone, tris(4-
diethylaminophenyl)methane, 1,1-bis(4
-dibenzylaminophenyl)propane, 2,2'-dimethyl-4,4'-bis(diethylamino)-triphenylmethane, etc. The compound represented by general formula (5) includes, for example, 9-(
Examples include 4-diethylaminostyryl)anthracene and 9-bromo-10-(4-diethylaminostyryl)anthracene. The compound represented by general formula (6) includes, for example, 9-(
4-dimethylaminobenzylidene) fluorene, 3-(
Examples include 9-fluorenylidene)-1-ethylrubazole. The compound represented by the general formula (7) includes, for example, 1,2
-bis(4-diethylaminostyryl)benzene, 1.
There is 2-bis(2,4-dimethoxystyryl)benzene. Examples of the compound represented by the general formula (8) include 3-styryl-9-ethylrubazole and 3-(4-methoxystyryl)-9-ethylrupazole. Examples of the compound represented by the general formula (9) include 4-diphenylaminostilbene, 4-dibenzylaminostilbene, 4-ditolylaminostilbene, 1-(4-diphenylaminostyryl)naphthalene, 1-(4- diethylaminostyryl) naphthylene, etc. The compound represented by the general formula (10) includes, for example, 4'
-diphenylamino-α-phenynorestinoleben, 4
'-Methylphenylamino-α-phenylstilbene, etc. The compound represented by the general formula (l1) includes, for example, l-
Phenyl-3-(4-diethylaminostyryl)-5-
(4-diethylaminophenyl)birazoline, 1-phenyl-3-(4-dimethylaminostyryl)-5-(4
-dimethylaminophenyl)virazoline, etc. The compound represented by general formula (l2) has. N,N'-diphenyl-N,N'-bis(3-methylephenyl)-(1.1'-bisphenyl)-4,4'-diamine, N,N'-diphenyl-N. Examples include N'-bis(chlorophenyl)-(1.1'-biphenylinole)-4,4'-diamine and 3,3'-dimethylbenzidine. The compound represented by the general formula (l3) includes diphenyl-
4-biphenylylamine, di(4-methylphenyl)-
4-biphenylylamine, di(4-methoxyphenyl)
Examples include -4-biphenylylamine. Other hole transport substances include, for example, 2.5-bis(4-diethylaminophenyl)-1.3.4-oxadiazole, 2.5-bis(4-(4-diethylaminostyryl)phenyl)- 1.3.4-oxydiazole, 2-
Oxadiazole compounds such as (9-ethylrubazolyl-3-)-5-(4-diethylaminophenyl)-1.3.4-oxadiazole, 2-vinyl-4-(2
There are low molecular weight compounds such as oxazole compounds such as -chlorophenyl)-5-(4-diethylaminophenyl)oxazole and 2-(4-diethynoleaminophenyl)-4-phenyloxazole. Also usable are polymeric compounds such as polyvinylcarbazole, halogenated polyN-vinylrubazole, polyvinylpyrene, polyvinylanthracene, bilene formaldehyde resin, and ethylrubazole formaldehyde resin. Examples of the electron transport substance include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinone dimethane, 2,4,7-trinitro-9-fluorenone. 2
, 4,5.7-tetranitro-9-fluorenone. 2
, 4,5.7-tetranitroxanthone. 2,4.8
-trinitrothioxanthone, 2,6.8-trinito-4}1-indeno[:1.2-b)thiophene-4-
on. Examples include 1,3,7-trinitrodibenzothiophene-5,5-dioxide. The photosensitive layer of the electrophotographic photoreceptor of the present invention can be of a normally charged type or a negatively charged functionally separated type by combining a charge generation layer and a charge transport layer. In the case of a negatively charged type, a charge generating layer containing a charge generating substance and a binder is formed on the substrate, and a charge transporting layer containing a charge transporting substance and a binder is formed thereon, but in the case of a positively charged type, a charge generating layer containing a charge generating substance and a binder is formed on the substrate. In this case, a charge generation layer,
Stack the charge transport layer in reverse order. Note that a charge transporting substance may be included in the charge generation layer, especially in the case of a positively charged structure, the sensitivity is improved. Furthermore, an intermediate layer may be provided between the photosensitive layer and the substrate in order to improve adhesion and charge blocking properties. Furthermore, a protective layer may be provided on the photosensitive layer in order to improve mechanical durability such as abrasion resistance. Binders used in forming the charge generation layer, charge transport layer and dispersed photosensitive layer include polycarbonate (bisphenol A type, bisphenol Z type), polyester, methacrylic resin, acrylic resin,
Polyethylene, vinyl chloride, vinyl acetate, polystyrene. Phenol resin, epoxy resin, polyurethane, vinylidene chloride, alkyd resin, silicone resin, polyvinyl rubber, polyvinyl butyral, polyvinyl formal, polyarylate, polyacrylamide, polyamide, phenoxy resin, etc. are used. These binders can be used alone or as a mixture of two or more. When creating a photoreceptor using the layer structure and materials described above. There is a preferable range for film thickness and material ratio. In the case of negatively charged type (layered structure of substrate/charge generation layer/charge transport layer). In the charge generation layer, the ratio of the charge generation substance to the binder is preferably 20 to 500% by weight, and the film thickness is preferably 0.1 to 5 tones. In the charge transport layer, the ratio of the charge transport substance to the binder is preferably 20 to 200% by weight, and the film thickness is preferably 5 to 50%. In the case of a positively charged type (stacked charge transport layer/charge generation layer on the base), the charge transport layer has a charge transport material ratio of 20 to 200% by weight and a film thickness of 5 to 50% by weight. It is preferable to do so. In the charge generation layer, the charge generation substance is preferably contained in an amount of 10 to 100% by weight based on the binder. Furthermore, it is preferable to include a charge transport substance in the charge generation layer, which has the effect of suppressing residual potential and improving sensitivity. In this case, the charge transport material is preferably contained in an amount of 20 to 200% by weight based on the binder. Further, the amount of the TEMPO derivative of the present invention added to the photosensitive layer is preferably 0.01 to 5.0% by weight based on the charge transport material when added to the charge transport layer in the case of a functionally separated type. ．． When added to the charge generation layer, it is preferably added in an amount of 0.1 to 20.0% by weight relative to the charge generation substance. In the case of a dispersed type, o
．． It is preferable to add oi to 5.0% by weight. TEM
If the amount of the PO derivative added is less than the lower limit, the effect of increasing durability cannot be obtained, and if it is more than the upper limit, it may cause negative effects such as a decrease in sensitivity. The intermediate layer provided as needed is generally made of resin as the main component, but considering that the photosensitive layer is coated on top of it with a solvent, these resins have poor solvent resistance to general organic solvents. It is desirable that the resin has a high Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate; alcohol-soluble resins such as copolymerized nylon and methoxymethylated nylon; and three-dimensional resins such as polyurethane, melamine resin, phenolic resin, and epoxy resin. Examples include curable resins that form a network structure. Further, fine powder pigments of gold tin oxide such as titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide, etc. may be added to the intermediate layer to prevent moire and reduce residual potential. Solvents or dispersion media used in forming the charge generation layer and the charge transport layer include ~,N'-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, 1,2-dichloroethane, Dichloromethane, monochlorobenzene. Tetrahydrofuran, dioxane, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate. Examples include dimethyl sulfoxide. Methods for forming the photosensitive layer include immersing the substrate in a coating solution for the charge generation layer and charge transport layer, and spraying the coating solution onto the substrate. Substrates used in the electrophotographic photoreceptor of the present invention include metal drums and sheets made of aluminum, brass, stainless steel, nickel, and the like. Materials such as polyethylene terephthalate, polypropylene, nylon, and paper are treated with conductivity by steaming metals such as aluminum and nickel, or by coating conductive substances such as titanium oxide, tin oxide, and carbon black with a suitable binder. Examples include sheet-like or cylindrical substrates such as plastic and paper. [Effects of the Invention] Since the electrophotographic photoreceptor of the present invention has the above structure, the photoreceptor characteristics such as charging property do not deteriorate even after repeated use over a long period of time, and it has high durability and good storage stability. It has extremely high practical value.

[Example] The present invention will be explained in more detail with reference to Examples below. Example 1 Alcohol-soluble polyamide (Amilan CM-8000
; manufactured by Toray Industries, Inc.) 1 part by weight and 8 parts by weight of methanol. To this solution dissolved in a mixed solvent containing 5 parts by weight of i-butanol, 3 parts by weight of titanium oxide powder (Tie Bake A-100; Ishihara Sangyo Co., Ltd. 1!) was added and dispersed in a ball mill for 12 hours. A coating solution for the intermediate layer was created. This has a long diameter of φ40. It was coated on an aluminum drum with a length of 255 cm using a dip coating method and dried to form an intermediate layer with a thickness of 24 cm. Next, 2 parts by weight of polyvinyl butyral resin (S-LEC BL-S: Sekisui Chemical Co., Ltd. 11) was dissolved in 125 parts by weight of 1,2-dichloroethane, and a mixture was prepared in the same manner as described in Japanese Patent Publication No. 49-4338. 1 part by weight of X-type metal-free phthalocyanine was added and ultrasonic dispersion was performed using an ultrasonic dispersion machine. The charge generation layer coating solution thus obtained was applied onto the intermediate layer by dip coating and dried to form a charge generation layer having a thickness of 0.57a. Furthermore, a charge transport substance 8 represented by the following structural formula (1)
Parts by weight, 10 parts by weight of polycarbonate resin (Panlite κ-1300: manufactured by Teijin Chemicals), silicone oil (KF-50)
: Manufactured by Shin-Etsu Chemical Co., Ltd.) o. oz parts by weight, 4-hydroxy-TEMPO O. 04 parts by weight of methylene chloride 8 parts
A charge transport layer coating solution was prepared by dissolving 5 parts by weight. This was applied to the charge generation layer by dip coating and dried to form a charge transport layer with a thickness of 20 layers. In this way, an electrophotographic photoreceptor was created. Example 2 4-oxoTE instead of 4-hydroxy-TENPO in Example 1! An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that MPO was used. Comparative Example 1 An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that 4-hydroxy-TEMPO was omitted. Example 3 A 2p thick film was deposited on an aluminum drum in the same manner as in Example 1.
The middle layer of a was formed. Next, polyvinyl butyral resin (S-LEC BL-S:
Sekisui Chemical Co., Ltd.) 5 parts by weight were dissolved in 150 parts by weight of cyclohexanone, 10 parts by weight of trisazo pigment represented by the following structural formula (A) were added thereto, dispersed for 48 hours in a ball mill, and further 210 parts by weight of cyclohexanone was added. In addition, dispersion was performed for 3 hours. This was taken out into a container and diluted with cyclohexanone so that the solid content was 1.5 wt. The charge generation layer coating solution thus obtained was applied onto the intermediate layer by dip coating and dried to form a charge generation layer having a thickness of 0.21. Further, a charge transport layer represented by the following structural formula (■) 8 parts by weight ti, (...; 10 parts by weight of polycarbonate resin (Panlite K-1300: manufactured by Teijin Chemicals), silicone oil (κF-50;
Shin-Etsu Chemical Co., Ltd.) 0.002 parts by weight, 4-hydroxy-TEMPOO. A charge transport layer coating solution was prepared by dissolving 04 parts by weight in 85 parts by weight of methylene chloride. This was dipped onto the charge generation layer. Applied using coating method and dried to a film thickness of 20pa
A charge transport layer was formed. In this way, the electrophotographic photoreceptor of the present invention was produced. Example 4 4-amino-cho 1 instead of 4-hydroxy-cho HMPO in fruit*m3! An electrophotographic photoreceptor was prepared in the same manner as in Example 3 except that NPO was used. Comparative Example 2 4-Hydroxy-τII in Example 3! An electrophotographic photoreceptor was prepared in the same manner as in Example 3 except that MPO was omitted. Comparative Examples 3 and 4 An electrophotographic photoreceptor was prepared in the same manner as in Example 3, except that the following compound was used instead of 4-hydroxy-TENPOo in Example 3. The electrophotographic photoreceptor obtained as described above was printed on a laser printer (PC-LASER-6000: ■ manufactured by Ricoh).
It was installed and evaluated. Evaluation was performed by measuring the surface potential of exposed and non-exposed areas in the printer. The surface potential was measured by removing the developing device and attaching a surface potential probe to the developing position. The results obtained are shown in Table 1. Table 1 As is clear from the results in Table 1, it is possible to obtain a highly sensitive and highly durable electrophotographic photoreceptor by adding a TEMPO derivative, especially 4-hydroxy-TEMPO, to the photosensitive layer of the electrophotographic photoreceptor. can. Patent applicant Ricoh Co., Ltd.

Claims (1)

[Claims] (1) In an electrophotographic photoreceptor in which a photosensitive layer containing at least a charge-generating substance and a charge-transporting substance is provided on a conductive substrate, the photosensitive layer contains 2,2,6,6-tetramethyl-1
- An electrophotographic photoreceptor containing a piperidinyloxy derivative.