JPS6373254A - Electrophotographic sensitive body containing hindered phenol compound - Google Patents

Abstract

PURPOSE:To obtain the titled body having excellent ozone resistance and repetition characteristics by incorporating a specific hindered phenol compd. to a photosensitive layer. CONSTITUTION:The photosensitive layer contains at least one of the hindered phenol compds. having at least one of constituting units shown by formulas II and III in the titled body comprising an azo compd. shown by formula I, as an electric charge generating substance in the photosensitive layer. In formulas II and III, R1 and R7 are each hydrogen atom or alkyl or aralkyl group, R2, R8 and R12 are each a branched alkyl group, R3-R6 and R9-R11 and R13-R15 are each hydrogen atom or a substituent, (m) or (n) is 0 or a positive integer, (m+n) is 2-4, Y is a binding group. Thus, the titled body having excellent characteristics such as anti-environmental property, less fatigue and deterioration due to repeated uses, is obtd.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to electrophotographic photoreceptors, and more particularly to improvements in organic photoconductive electrophotographic photoreceptors.

[Prior art]

In an electrophotographic copying machine using the Carlson method, after the surface of a photoreceptor is charged, an electrostatic latent image is formed by exposure, the electrostatic latent image is developed with toner, and then the visible image is transferred to paper or the like. Transfer and fix. At the same time, the photoreceptor is subjected to removal of adhered toner, neutralization of static electricity, and surface cleaning, and is used repeatedly over a long period of time. Therefore, as an electrophotographic photoreceptor, it not only has electrophotographic properties such as good charging characteristics and sensitivity, and low dark decay, but also has good printing durability, abrasion resistance, moisture resistance, etc. after repeated use. physical properties, ozone generated during corona discharge,
It is also required to have good resistance to ultraviolet rays and the like during exposure (environmental resistance). Conventionally, as electrophotographic photoreceptors, inorganic photoreceptors having a photosensitive layer mainly composed of an inorganic photoconductive substance such as selenium, zinc oxide, or cadmium sulfide have been widely used. On the other hand, the use of various organic photoconductive substances as materials for photosensitive layers of electrophotographic photoreceptors has been actively developed and researched in recent years. For example, Japanese Patent Publication No. 50-10496 describes an organic photoreceptor having a photosensitive layer containing poly-N-vinylcarbazole and 2,4,7-dolinitro-9-fluorenone. However, this photoreceptor is not necessarily satisfactory in terms of sensitivity and durability.In order to improve these drawbacks, the charge generation function and charge transport function are assigned to different substances in the photosensitive layer. Attempts have been made to develop organic photoreceptors with high sensitivity and durability. In such so-called function-separated type electrophotographic photoreceptors, substances that exhibit each function can be selected from a wide range of materials, so it is relatively easy to produce electrophotographic photoreceptors with arbitrary characteristics. ·Is possible. Many substances have been proposed as charge-generating substances that are effective for such functionally separated electrophotographic photoreceptors. Examples of using inorganic substances include, for example, Japanese Patent Publication No. 43-1619
As described in No. 8, there is amorphous selenium. This is combined with an organic charge transport material. In addition, many electrophotographic photoreceptors using organic dyes or organic pigments as charge-generating substances have been proposed.
-37543, 55-22834, 54-79
It is already known from No. 632, No. 56-116040, etc. However, in the electrophotographic process, since ozone and other active substances are generated during charging by corona discharge, there is a problem in that charging characteristics and sensitivity deteriorate due to the influence of these active substances. In particular, during repeated use, the charging characteristics deteriorate significantly as the exposure time to ozone and other active substances increases cumulatively.

[Purpose of the invention]

An object of the present invention is to provide a photoreceptor which has excellent environmental resistance, particularly ozone resistance, and which has excellent repeatability, and which significantly reduces development problems such as a decrease in charging ability, an increase in dark conduction, and a decrease in sensitivity when used in edge-reversing applications. Our goal is to provide the following.

[Structure and effects of the invention]

The object of the present invention is to provide an electrophotographic photoreceptor in which an azo compound represented by the following general formula (It) is used as a charge generating substance in the photosensitive layer. This is achieved by an electrophotographic photoreceptor characterized by containing a hindered phenol compound having at least one structural unit represented by [Ib]. The hindered phenol compound referred to in the present invention is a phenol compound characterized by the presence of a bulky atomic group at the ortho position of a phenolic hydroxyl group. A commonly used bulky atomic group is a branched alkyl group. Although the N tM of this effect is not certain, it is thought that steric hindrance suppresses the thermal vibration of the phenolic hydroxyl group and prevents the influence of external active substances. In the aspect of the present invention, a hindered phenol compound having at least one structural unit represented by the following general formula [1a) or [Ib] in the molecule is used as the hindered phenol compound. General formula [Ia) OR. General formula (Ib) where R and R7 are hydrogen atoms or alkyl groups, aryl groups, aralkyl groups, R2 and R8゜R52 are branched alkyl groups, R), R-, Rs and R1 and R-, R+. , R11 and R, , R, 4, R, represent a hydrogen atom or a substituent. n is 0 or a positive integer, and m+n is 2-4. Moreover, Y is a linking group. The alkyl group represented by R1 and R2 is an alkyl group having 1 to 40 carbon atoms and may have a substituent. Substituents for R and -R include aryl, alkoxy, acid, and amide. , halogen, etc. are possible. Further, examples of the alkyl group include a benzyl group and a phenethyl group. The branched alkyl group represented by R2 and Ra+R12 is a branched alkyl group having 1 to 40 carbon atoms, such as (1) butyl, (see) butyl, (see) octyl, (1>octyl group, etc.). Possible substituents for R1 to R, and R, to R1, and R13 to R1 include, for example, aryl, alkoxy, acid, amide, halogen, etc. The linking group Y may be -, and the value of n may be Typical examples of Y include methylene group, ethylene group, propylene group, phenylene group, sulfide, polysulfide, etc. In the present invention, Y is not present and the phenyl groups are directly bonded to each other. Further, in embodiments of the present invention, the photoconductive material contained in the photosensitive layer may include a charge generating material (referenced as CGM) and an IL charge transporting material (referenced as CTM). Preferably, the CGM is an azo compound in the present invention,
In particular, an azo compound represented by the following general formula [■] is used. General formula [■] In the formula, R to R24 represent a hydrogen atom or an arbitrary substituent, and examples of the substituent include alkyl, alkoxy, aryl, aralkyl, halogen, acid, amide, and nitrile. R25 and R26 are hydrogen atoms or alkyl groups,
It represents an aromatic group or a heterocyclic group, and preferred examples of Rts and R2s include an alkyl group having 1 to 12 carbon atoms, benzene, naphthalene, pyridine, thiophene, pyrrole and the like. These may have substituents such as an alkyl group, an alkoxy group, a cyan group, a halogen atom, an amide group, and an amide group. Ar represents a heterocycle, and preferred examples of Ar include the following, which may have a substituent such as an alkyl group, an alkoxy group, a cyano group, a halogen atom, an amino group, an amide group, etc. So R5. R1 represents a hydrogen atom, an alkyl group, or a phenyl group. cp represents a Kabra residue in the azo coupling reaction. Preferred examples of cp include the following. -C5-CONH-^1 or -CH=N-NH-^
2, where ^1. ^2 is a substituted or unsubstituted aromatic group, preferably an alkyl group, an alkoxy group,
Examples include phenyl groups and naphthyl groups with or without substituents such as halogen atoms, cyano groups, nitro groups, and amino groups. The hindered phenol compound having a structural unit represented by the general formula (Ig) or (Ib) in the molecule is represented by the general formula (Ig) or (Ib).
By using the photoreceptor containing the azo compound represented by II), deterioration in acceptance potential and sensitivity or increase in residual potential during repeated use can be reduced. Furthermore, the environmental resistance is improved, especially the durability against ozone generated during corona discharge. The present invention will be explained in more detail below. The photoreceptor of the present invention has a support 1 as shown in FIG.
(with a charged layer on a conductive support or sheet)
A charge generation layer 2 (hereinafter referred to as CGL) containing CGM and a binder resin as necessary is formed as a lower layer on top, and a charge transport layer 3 (hereinafter referred to as CTL) containing CTM and a binder resin as necessary. As shown in FIG. 2, the photosensitive layer 4 has a laminated structure on the support 1, with CTL3 as the lower layer and CGL2 as the upper layer. As shown in FIG. 3, examples include those in which a single-layer photosensitive layer 4 containing CGL, CTM, and optionally a binder resin is provided on a support 1, as shown in FIG. Further, CGL may contain both CGM and CTM, protective N (CGL) may be provided on the photosensitive layer, and an intermediate layer may be provided between the support and the photosensitive layer. The hindered phenol compound of the present invention can be used in CGL, CTL, intermediate monolayer photosensitive layer or OC constituting the photoreceptor.
L may be contained in any layer, and may be contained in multiple layers. The effect of the present invention is more conspicuously exhibited in C
This is a photoreceptor with a structure N in which GL is an upper layer and CTL is a lower layer. Next, typical specific examples of hindered phenol compounds having a structural unit represented by the general formula (Im) or [:Ib) that are preferably used in the present invention are shown below, but the present invention is not limited to these. do not have. I: Hindered Phenol Exemplary Compound 0■ Shi■3 11+1 1I ■-18 UH Co■-21 ■-22 υ■ ■-24 ■-25 I-26 I ■-28 These compounds are generally commercially available, For example, Irganox-245,259,565,101O1103
5,1076,1081,1098,1222,133
0, MD1024 (Ciba Geigy), mark ^ 0
-20, ^0-30, ^0-40, 80-50, ^0-
60 (Adeka Argus), Sumilizer IIHT,
S, BP-76, MOP-5, GM, B[1
In addition to being available as M-5-WX-R (Sumitomo Chemical), it can also be easily synthesized by conventionally known methods. The addition rate of the compound of the present invention is not fixed depending on the layer structure of the photoreceptor, the type of CTM, etc., but when it is added to CGL, it is added at 0.1 to 200 parts per 100 parts of CGM,
Particularly preferred is 0.1 to 100 layers. If you put it in CT L, 0 for CTM100 heavy area.
．． 01 to 70 parts, particularly preferably o, i to 50! ! t
This is the ji part. When included in an intermediate layer such as a subbing layer or a protective layer, the amount of
This is Jutanbe. Next, as a representative example of the azo compound represented by the general formula (n) used in the present invention, Illustrated Compound 1 will be listed below. (2): Azo-based exemplified compound It-<A) Next, CTMs that can be used in the present invention are not particularly limited, but include, for example, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, indacilone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds, pyrazoline derivatives, oxacilone derivatives, benzothiazole derivatives,
Benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives,
It may be an aminostilbene derivative, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene, or the like. However, in addition to its excellent ability to transport holes generated during light irradiation to the support side, those suitable for combination with the CGM described above are preferably used. Such CTMs include, for example, the following general formulas (A) to (■1 ) and other compounds represented by (1). ill: CTM compound (general formula) % formula % () [() III-(F) R-'. 111- (H) III-(1) Others 1[-358 1[-359 [1-360 1[-361 The CTM compound shown in the maximum above is disclosed in JP-A-61-563
The compounds described in No. 51 can be applied as they are. The layer structure of the photosensitive layer of the photoreceptor of the present invention has a laminated structure and a single layer structure as described above.
, either the single-layer photosensitive layer or the OCL, or multiple layers may contain one or more electron-accepting substances for the purpose of improving sensitivity, reducing residual potential or fatigue during repeated use, etc. can. Electron-accepting substances that can be used in the photoreceptor of the present invention include:
For example, succinic anhydride, maleic anhydride, dibromaleic anhydride, phthalic anhydride, tetrachlorophthalic anhydride,
Tetrabromo phthalic anhydride, 3-nitro phthalic anhydride,
4-nitrophthalic anhydride, pyromellitic anhydride, mellitic anhydride, tetracyanoethylene, tetracyanoquinodimethane, 0-dinitrobenzene, -1-dinitrobenzene, 1°3.5. - trinitrobenzene, varanitrobenzonitrile, vicryl chloride, quinone chlorimide, chloranil, brumanil, 2-methylnaphthoquinone,
dichlorodicyanobara benzoquinone, anthraquinone,
Dinitroanthraquinone, trinitrofluorenone, 9
-Fluorenonedene [dicyanomethylenemalonodinitrile], polynitro-9-fluorenonedene [dicyanomethylenemalonodinitrile], picric acid, 0-nitrobenzoic acid, p-nitrobenzoic acid, 3,5-dinitrobenzoic acid, penta Examples include fluorobenzoic acid, 5-nitrosalicylic acid, 3,5-dinitrosalicylic acid, and phthalic acid. Furthermore, silicone oil may be present as a surface modifier, and an ammonium compound may be contained as a durability improver. Examples of binder resins that can be used in the photosensitive layer in the present invention include polyethylene, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, epoxy resin, polyurethane resin, phenol resin,
Addition polymerization resins such as polyhydroxystyrene resins, polyester resins, alkyd resins, polycarbonate resins, silicone resins, melamine resins, polyaddition resins, polycondensation resins, and two or more of the edge turning units of these resins In addition to insulating resins such as vinyl chloride-vinyl acetate copolymer resins and vinyl chloride-vinyl acetate-maleic anhydride copolymer resins, polymeric organic resins such as poly-N-vinyl carbazole Examples include semiconductors. Further, the intermediate layer functions as an adhesive layer or a barrier layer, and in addition to the binder resin, for example, polyvinyl alcohol, ethyl cellulose, carboxymethyl cellulose, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-anhydrous Maleic acid copolymer, casein, N
-Alkoxymethylated nylon, starch, etc. are used. Next, the conductive support supporting the photosensitive layer is a metal plate made of aluminum, nickel, etc., a metal drum or metal foil, a plastic film deposited with aluminum, tin oxide, indium oxide, etc., or paper coated with a conductive substance. , a film or drum of plastic or the like can be used. The CGL can be provided by vacuum-depositing the above-mentioned CGM on the support, or by applying a solution or dispersion of CGM alone or together with a suitable binder resin in a suitable solvent and drying it. A ball mill, homomixer, sand mill, ultrasonic disperser, attritor, etc. are used for dispersing CGM. Examples of solvents used to form CGL include N, N
-Dimethylformamide, benzene, toluene, xylene, monochlorobenzene, 1,2-dichloroethane, dichloromethane, 1,1,2-trichloroethane, tetrahydrofuran, methyl ethyl ketone, ethyl acetate, butyl acetate, and the like. CGM per 100 parts by weight of binder resin in CGL is 20
The weight is preferably 25 to 400, particularly preferably 25 to 400. The thickness of the CGL formed as described above is preferably 0.01 to 10 .mu.m, particularly preferably 0.1 to 5 .mu.m. Further, CTL can be formed by applying and drying the above-described CTM in the same manner as the above-mentioned CGL, that is, by melting and dispersing the above-mentioned CTM alone or together with the above-mentioned binder resin. CTM is 20 per 100 parts by weight of binder resin in CTL
~200 parts, preferably 30-150:ffi J
It is considered part i. The thickness of the CTM formed is preferably 5 to 50 μ-1
Particularly preferred is 5 to 30 μm. In the present invention, the binder of the protective layer provided as necessary has a volume resistivity of 10''Ω・811 or more, preferably 1Q16Ω・611 or more, more preferably 10′3Ω
・Transparent resin of am or higher is used. Further, the binder may be a resin that is cured by light or heat, and examples of the resin that is cured by light or heat include thermosetting acrylic resin, silicone resin, epoxy resin, urethane resin, urea resin, phenol resin, Polyester resin, alkyd resin, melamine resin, photocurable cinnamon 1!12t
l fats, etc., or their copolymerization or cocondensation resins,
In addition, all photo- or thermosetting resins used in electrophotographic materials can be used. If necessary, the protective layer may contain less than 50% by weight of a thermoplastic resin for the purpose of improving processability and physical properties (preventing cracks, imparting flexibility, etc.). Such thermoplastic resins include, for example, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, epoxy resin, butyral resin, polycarbonate resin, silicone resin, or copolymer resins thereof, such as vinyl chloride-vinyl acetate copolymer resin. polymer resin,
Vinyl chloride-vinyl acetate-maleic anhydride copolymer resins, polymeric organic semiconductors such as poly-N-vinylcarbazole, and other thermoplastic resins used in electrophotographic materials can all be used. Further, the protective layer may contain an electron-accepting substance,
The pond may contain a UV absorber or the like to protect CON2 if necessary, and is dissolved in a solvent together with the binder, applied by dip coating, spray coating, blade coating, roll coating, etc., and dried in a cage. The layer thickness is 2 μm or less, preferably 1 μm or less.

【Example】

Hereinafter, the present invention will be explained with reference to examples, which will explain how the present invention can be carried out. It is not limited to the following. Example 1 Polyvinyl butyral resin rXYH was deposited on a conductive support made of a polyester film deposited with aluminum.
Thickness 0.2 made of "L" (manufactured by Union Carbide)
The middle layer of the μ heel was formed. Next, 1 part by weight of Exemplified Compound (II-34) was added to a polycarbonate resin [Panlite L-1250J (manufactured by Teijin Chemicals), 0.5 parts by weight, 1 part by weight of 1,2-dichloroethane.
A CG of 0.2 μ-
L was formed. Next, the following exemplified compound (■- belonging to III-(C))
100) 12-layered part, polycarbonate I-resin "Panlite 11300J (manufactured by Teijin Kasei) 15-layered part, 1
．． Two parts of the exemplified compound (I-5N) were added to a solution of 120 parts of 2-dichloroethane, and the mixture was coated using a blade coater to form a CTL with a thickness of 23 μm to form a photoreceptor of the present invention. This is designated as Sample 1. Comparative Example 1 Except for the exemplified compound (f-5) in Example 1,
A comparative photoreceptor was obtained in the same manner as in Example 1. This will be referred to as comparative sample 1. Examples 2 to 8 Exemplary compound of CGM in Example 1 (II-34)
The photosensitive material of the present invention was prepared in the same manner as in Example 1, except that the exemplified compound (III-100> of CTM and the exemplified compound (1-5) of the improver were changed as shown in Table 1. Body 5: Obtained.This is referred to as Samples 2 to 8.Comparative Examples 2 to 8 Exemplary compounds (I-9) as improving agents in Examples 2 to 8
Comparative photoreceptors were obtained in the same manner as in Examples 2 to 8, except that Exemplary Compound (1-1) was excluded. Refer to Table 3-1, which refers to comparative samples 2 to 8. CTML [-100・
...General formula I[1-(C)Ill-133...General formula III -(D)[1-229...General formula I[[-
(F)1[-210...General formula 1-(F) m-tto...General formula 1[[-(C)Ill-
88...General formula III-(B) tri03...General formula DI-(G)■-33...General formula 11[-(A
) Example 9 Vinyl chloride-vinyl acetate-
An intermediate layer having a thickness of 1 .mu.I made of vinyl alcohol copolymer "S-LEC A-5" (manufactured by Tanezu Kagaku Co., Ltd.) was formed. Next, 1 part by weight of Exemplified Compound (II-1) was mixed with 0.8 parts by weight of polyvinyl formal resin "Denka Formal #20" (manufactured by Denki Kagaku Kogyo Co., Ltd.) and 1 part by weight of 1,2-dichloroethane.
A CGL of 0.3μ steel was formed by spray coating a solution dispersed for 48 hours using a ball mill in a solution of 0.3μ steel. Next, the exemplified compound #'lj (■ belonging to m-(1))
-358) 10 parts by weight, polyester resin "Vylon 2"
00. (3 parts by weight of Exemplified Compound (1-10) was added to a solution of 1 part by weight of H2,5 (manufactured by Toyobo Co., Ltd.) and 100 parts by weight of 1,2-dichloroethane, and the mixture was coated using a blade coater to a thickness of 2.
A CTL of 0 μ- was formed to obtain a photoreceptor of the present invention. This will be referred to as sample 9. Comparative Example 9 A comparative photoreceptor was obtained in the same manner as Example PA9 except that the exemplified compound (+-10) in Example 9 was removed. Let's use this as a comparison sample. Example 10 1 part by weight of exemplified compound (II-32) and polycarbonate resin "Panlite L-1250J" were placed on a conductive support made of a polyester film on which aluminum was vapor-deposited.
0.5 parts by weight, 0.5 parts by weight of exemplary compound (1-15),
1.2-Jiku Yokkajo 2F 100 heavy-duty parts were dispersed for 10 hours using a sand mill, and the liquid was applied with a wire bar.
．． A charge generation layer having a thickness of 3 μm was formed. Next, the following exemplified compound (■- in III-(C))
11402 parts by weight, 15 parts by weight of polycarbonate resin "Panlite K-1300", Exemplary compound (1-15)
A solution of 0.12 parts by weight and 100 parts by weight of 1.2-dichloroethane was applied using a blade coater to form a CTL with a thickness of 25 μm, thereby obtaining photoreceptor 3 of the present invention. This is designated as sample 10. Comparative Example 10 A comparative photoreceptor was obtained in the same manner as in Example 10, except that the exemplified compound (1-15) in Example 10 was removed from CGL and CTL. This will be referred to as a comparative sample of 1°. lll-114...General formula I [1-(C) Implementation PA1
1 A 0.3μ-thick film made of polyvinyl formal resin “Vinylec LJ (manufactured by Tanezu Kagaku Co., Ltd.)” was placed on a conductive support made of a polyester film on which aluminum was vapor-deposited.
An intermediate layer was formed. Next, 11 parts of the exemplified compounds (■ to 47), polyvinyl butyral resin "S-LEC BLS" (manufactured by M Suikagaku Co., Ltd.)
A CGL was formed by dispersing 11 parts of 1,2-dichloroethane and 100 parts of 1,2-dichloroethane using an ultrasonic disperser using a wire bar. Next, the following exemplified compound (■- belonging to Ill-(B))
77>10 heavy foot part, polycarbonate resin "Panlite L-1250, 12 heavy foot part, 1,2-dichloroethane 1
CT of 18μ thick ring by applying the liquid of 00 weight with a blade
0 then polyester resin "Vylon 20" formed L
0. l ffl Ibe, Exemplary Compound (1-14) 0.
A solution consisting of 4 parts by weight and 100 parts by weight of 1,2-dichloroethane was coated with a blade to form a protective layer having a thickness of 0.5 μm to obtain a photoreceptor of the present invention. This is designated as sample 11. Comparative Example 11 A comparative photoreceptor was obtained in the same manner as in Example 11, in which no protective layer was formed. This will be referred to as comparative sample 11. ■-77...General formula III-([3) Example 12 Novolac resin "5K-105J (
An intermediate layer having a thickness of 0.4 μm was formed. Next, 1 part by weight of Exemplified Compound (Il-43), 0.3 parts by weight of polycarbonate resin [Panlite L-1250, 0.6 parts by weight of Exemplary Compound (1-1), 100 parts by weight of 1,2-dichloroethane. was dispersed in a sand mill for 10 hours, and then applied with a wire bar to form a 0.3 μ-thick C.
GL was formed. Next, the following exemplified compound (I[[- (F))
202) A solution of 10 parts by weight, polycarbonate resin [Panlite K-1300J, 11 parts by weight, and 100 parts by weight of 1,2-dichloroethane was applied with a blade to a thickness of 20 μm.
A CTL of I was formed to obtain a photoreceptor of the present invention. This will be referred to as sample 12. Comparative Example 12 A comparative photoreceptor was obtained in the same manner as in Example 12, except that exemplified compound (1-1) was excluded. This will be referred to as comparative sample 12. m -202...General formula I[[-(F) evaluation
1 The samples obtained in Examples 1 to 12 and Comparative Examples 1 to 12 above were evaluated as follows. That is, ozone gas generated in an ozone generator (Japan Ozone Co., Ltd. model 0-1-2) is introduced into an electrostatic tester (Kawaguchi Denki Seisaku Seisaku, model 5P-428) equipped with a sample, and the ozone inside is The concentration was 90 pp-. First, the surface potential (initial potential) ■ after being negatively corona charged for 5 seconds under a 40 μA discharge condition and then left for 5 seconds. [V], followed by white light exposure to reduce the surface potential to -
The exposure amount E 5B [i'ux-see] required to lower the voltage from 500 [V] to -50 [V] was measured. This operation is repeated 100 times, and the initial potential is V1° after 100 times. is measured, and the retention rate of the initial TL position is V1°. /V O was determined and used as an evaluation of ozone resistance. The results are shown in Table 3. Table 2 Example 13 On a conductive support made of a polyester film deposited with aluminum, 5-fold violet part of exemplary compound (n-45) and the following exemplary compound (I[■-234 belonging to I-(F)) were prepared.
), 1 part by weight of the exemplary compound (into I-5), 10 parts by weight of polycarbonate resin Panlite L-1250J, and 200 parts by weight of 1,2-dichloroethane were dispersed in a sand mill for 8 hours. Coated to a thickness of 15
A μ-photosensitive layer was formed. This will be referred to as sample 13. Comparative Example 13 A comparative photoreceptor was obtained in the same manner as in Example 13, except that exemplified compound N-, 5) was removed. This will be referred to as comparative sample 13. lll-234...General formula III-(F) evaluation
2 The samples of Example 13 and Comparative Example 13 were evaluated in the same manner as Evaluation 1 except that the corona charging in Step 1 in Evaluation 1 was changed to positive corona charging. The results are shown in Table-3. Table 3 Example 14 Polyhydroxystyrene resin [Resin MJ
(manufactured by Marukubi Petrochemical Co., Ltd.) with a thickness of 0.5 μm.
IM was formed. Next, Exemplified Compound (II-34) 11 parts, polyvinyl formal resin "Denka Polmar #20J O,6
A charge generating layer with a thickness of 0.25 μm was formed by dispersing 22,100 heavy weight parts of 1.2-Jiku Yokkagami using a sand mill for 10 hours and applying the resulting liquid by dip coating. Formed. Next, ■ belonging to the following exemplified compound (IIl-(F))
-222) 12-fold leg part, exemplary compound (1-9N, double-layer part, polycarbonate 1 to resin [Panlite K -13Q
A solution containing 16 parts of OJ and 2120 parts of 1,2-Dicrowaera was applied by dip coating to form a charge transport layer with a thickness of 22 .mu.m to obtain a photoreceptor of the present invention. This will be referred to as sample 14. Comparative Example 14 A comparative photoreceptor was obtained in the same manner as in Example 14, except that Exemplary Compound (1-9) was removed. This was designated as Comparative Sample 14. 1■-222...General formula IM-(F) evaluation f+Ii
3 The samples obtained in Example 14 and Comparative Example 14 were negatively charged, exposed, and exposed according to the Carlson process under conditions such that the ozone concentration near the charged electrode was 50 ppm.
Repeat the static elimination process 10,000 times, and the charged potential V
Changes in B(Vl and potential Vw [V:l) after exposure were measured. The results are shown in Table 4. Table 4 [Effects of the Invention] As described above, the photoreceptor of the present invention has excellent environmental resistance. Furthermore, the photosensitive material of the present invention shows a remarkable improvement effect on phenomena such as a decrease in charging ability and an increase in dark conductivity due to ozone and other active substances generated during charging. In the body, it has the effect of improving the charging potential and reducing dark decay, and therefore has excellent initial characteristics even in an environment with a low ozone temperature of 4 degrees Fahrenheit, and has extremely low fatigue and deterioration due to repeated use. Shows excellent properties.

[Brief explanation of the drawing]

1 to 3 are cross-sectional views of examples of embodiments of the photoreceptor of the present invention. 1... Conductive support 2... Charge generation layer (CGL) 3... Charge transport layer (CTL)

Claims (1)

[Scope of Claims] In an electrophotographic photoreceptor using an azo compound represented by the following general formula [II] as a charge generating substance in the photosensitive layer, the photosensitive layer contains an azo compound represented by the following general formula [I a] or [ An electrophotographic photoreceptor comprising a hindered phenol compound having at least one structural unit represented by Ib]. General formula [I a] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ General formula [I b] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, R_1 and R_7 are hydrogen atoms, alkyl groups, aralkyl groups, R_2 and R_8, R_1_2 are branched alkyl groups, R_3, R_4, R_5 and R_6
and R_9, R_1_0, R_1_1, and R_1_
3, R_1_4 and R_1_5 represent a hydrogen atom or a substituent. m and n are 0 or a positive integer, and m+n is 2 to 4. Moreover, Y is a linking group. ] General formula [II] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [In the formula, =Q is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲
There are mathematical formulas, chemical formulas, tables, etc. ▼ or = represents Ar,
R_2_5 and R_2_6 represent a hydrogen atom, an alkyl group, an aromatic group, or a heterocyclic group, and these groups may be substituted. Ar represents a heterocycle and may be substituted. R_1_9 to R_2_4 represent a hydrogen atom or a substituent. Cp represents a coupler residue in an azo coupling reaction. ]