JPH0675204B2 - Electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor containing a compound having a hindered phenol structural unit.

BACKGROUND OF THE INVENTION In the electrophotographic copying machine of the Carlson method, after charging the surface of a photoreceptor, an electrostatic latent image is formed by exposure, the electrostatic latent image is developed with toner, and then the visible image is formed. Transfer the image to paper and fix it. At the same time, the photoconductor is subjected to removal of adhered toner, charge removal, and surface cleaning, and is repeatedly used for a long period of time.

Therefore, as an electrophotographic photosensitive member, of course, electrophotographic characteristics such as good charging characteristics and sensitivity and small dark attenuation are not only provided, but in addition, printing durability, abrasion resistance, moisture resistance, etc. in repeated use Physical properties and ozone generated during corona discharge,
It is also required to have good resistance (environmental resistance) to ultraviolet rays during exposure.

Conventionally, as an electrophotographic photoreceptor, an inorganic photoreceptor having a photosensitive layer containing an inorganic photoconductive substance such as selenium, zinc oxide, or cadmium sulfide as a main component has been widely used.

On the other hand, the use of various organic photoconductive materials as materials for the photosensitive layer of an electrophotographic photoreceptor has been actively developed and studied 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-trinitro-9-fluorenone. However, this photoreceptor is not always satisfactory in sensitivity and durability. In order to improve such a defect, an attempt has been made to develop an organic photoreceptor having high sensitivity and high durability by separately sharing a charge generating function and a charge transporting function with different substances in a photosensitive layer. ing. In the so-called function-separated type electrophotographic photoreceptor, the substances exhibiting the respective functions can be selected from a wide range of substances, so that an electrophotographic photoreceptor having arbitrary characteristics can be produced relatively easily. It is possible.

Many substances have been proposed as charge generating substances effective for such a function-separated type electrophotographic photoreceptor. An example of using an inorganic substance is amorphous selenium as described in, for example, Japanese Patent Publication No. 43-16198. It is combined with an organic charge transport material.

A number of electrophotographic photoreceptors using organic dyes and organic pigments as charge generating substances have also been proposed. For example, those having a photosensitive layer containing a bisazo compound are disclosed in JP-A-47-
37543, 55-22834, 54-79632, 56-11604
It is already known by No. 0 etc.

However, in the electrophotographic process, ozone and other active substances are generated at the time of charging by corona discharge.
Decrease in sensitivity and increase in residual potential pose problems.

In particular, in repeated use, the exposure time to ozone and other active substances cumulatively increases, so that the charging characteristics, the sensitivity decrease, and the residual potential increase become significant.

In order to improve the above characteristics, for example, JP-A-56-130759 and 57-57.
As described in -73744 and 57-122444, even if an antioxidant is added, the one with good charging characteristics causes a decrease in initial sensitivity, and the one with good initial sensitivity does not improve deterioration due to repetition. However, there is a drawback in that the initial sensitivity and the charging characteristics are not satisfactory if the deterioration due to repetition is small.

[Object of the Invention] The object of the present invention is excellent in environment resistance, particularly ozone resistance, and phenomena such as a decrease in charging ability, an increase in dark decay, a decrease in sensitivity, and an increase in residual potential during repeated use are remarkably reduced. Another object of the present invention is to provide an electrophotographic photoreceptor having excellent repeatability.

[Structure of the Invention] The above-mentioned object of the present invention is a compound having a hindered phenol structural unit in an electrophotographic photoreceptor having a photosensitive layer containing a compound represented by the following general formula [A] on a conductive substrate. It is achieved by an electrophotographic photosensitive member characterized by containing.

General formula [A] In the formula, R ₁ represents a hydrogen atom or a substituent, R ₂ represents a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, Ar ₁ represents a hydrogen atom, a substituted or unsubstituted phenyl. Represents a group or a substituted or unsubstituted naphthyl group, Ar ₂ represents a substituted or unsubstituted phenylene group or a substituted or unsubstituted naphthylene group, Ar ₃ and Ar ₄ are each substituted or unsubstituted alkyl group, substituted Alternatively, it represents an unsubstituted phenyl group or a substituted or unsubstituted naphthyl group, and n represents 0 or 1.

The so-called hindered phenol structural unit in the present invention is a phenolic structural unit characterized by the presence of a bulky atomic group at the ortho position of the phenolic hydroxyl group or alkoxy group.

Branched alkyl groups are generally preferred as bulky atomic groups.

The mechanism of its action and effect is not clear, but it is thought that the steric hindrance formed by the bulky atomic group suppresses the thermal vibration of the phenolic hydroxyl group or the alkoxy group or the influence of the external active substance.

In the present invention, the hindered phenol structural unit is preferably represented by the following general formula [I].

General formula [I] In the formula, R ₆ is a branched alkyl group, R ₇ , R ₈ and R ₉ are each a hydrogen atom, a hydroxy group, an alkyl group or an aryl group, and at least two of R ₇ , R ₈ and R ₉ are mutually To form a ring. R ₁₀ represents a hydrogen atom, an alkyl group or an alkylidene group.

R ₆ is preferably a tert- or sec-alkyl group having 3 to 40 carbon atoms.

The alkyl group of R ₇ , R ₈ and R ₉ is preferably one having 1 to 40 carbon atoms, and the aryl group includes a phenyl group, a naphthyl group, a pyridyl group and the like.

When R ₇ and R _{8 form a} ring, a chroman ring is preferable.

The alkyl group and alkylidene group represented by R ₁₀ are preferably an alkyl group having 1 to 40 carbon atoms and an alkylidene group, and particularly preferably an alkyl group having 1 to 18 carbon atoms and an alkylidene group.

Next, typical specific examples of the compound having a hindered phenol structural unit (hereinafter referred to as the HP compound of the present invention) used in the present invention will be shown, but the invention is not limited thereto.

Exemplary compound having a hindered phenol structural unit The HP compound of the present invention can be synthesized by various methods, and some of the above-exemplified compounds can be obtained as commercial products.

Further, in an embodiment of the present invention, the photoconductive material contained in the photosensitive layer preferably comprises a charge generating material (generally designated as CGM) and a charge transport material (generally designated as CTM).

The photosensitive member of the present invention is, for example, as shown in FIG.
(A conductive support or sheet provided with a conductive layer)
A charge generation layer 2 (hereinafter also referred to as CGL) containing CGM5 and optionally a binder resin as a lower layer
A photosensitive layer 4 having a laminated structure having a charge transport layer 3 containing TM6 and optionally a binder resin (hereinafter, also referred to as CTL) as an upper layer, provided on a support 1 as shown in FIG. And a photosensitive layer 4 having a laminated structure in which CTL3 is the lower layer and CGL2 is the upper layer, and a single layer containing CGM5, CTM6 and optionally a binder resin on the support 1 as shown in FIG. Examples thereof include those provided with the photosensitive layer 4 having the structure.

Further, both CGM and CTM may be contained in CGL, a protective layer (OCL) may be provided on the photosensitive layer, and an intermediate layer may be provided between the support and the photosensitive layer.

The HP compound of the present invention may be contained in any one of CGL, CTL, intermediate layer, single-layer photosensitive layer or OCL constituting the photoreceptor, or may be contained in a plurality of layers. In the case of a multi-layered photoreceptor, the HP compound of the present invention is on the surface side (the side far from the support).
Is preferably added to the layer. The addition method is CGL, C
When the HP compound of the present invention is dissolved or dispersed in a coating solution used for forming TL, or when CGL, CTL, etc. are formed by vacuum vapor deposition, the compound of the present invention is co-evaporated with CGM and CTM. There is a way to do it.

The addition amount of the HP compound of the present invention is not constant depending on the layer structure of the photoconductor, the type of CTM, etc., but when it is added to CGL, CTL as the lower layer on the support and C as the upper layer thereon.
In the so-called positive charging type photoreceptor having GL, the amount is 0.05 to 10 parts by weight, preferably 0.5 to 5 parts by weight, relative to 100 parts by weight of CGM. Furthermore, in a so-called negative charging type photoreceptor having CGL and CTL respectively on the support,
It is 0 to 1 part by weight, preferably 0 to 0.5 part by weight, relative to 100 parts by weight of CGM.

When it is added to CTL, it is 0.02 to 30 parts by weight, and particularly preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of CTM in both cases of positive charging type and negative charging type.

When it is added to an intermediate layer such as an undercoat layer or a protective layer, the amount is 0.01 to 200 parts by weight based on 100 parts by weight of the binder resin constituting the layer.

Next, as the CGM suitable for the present invention, generally, any of inorganic pigments and organic dyes can be used as long as they absorb visible light and generate free charges. In addition to inorganic pigments such as amorphous selenium, trigonal selenium, selenium-arsenic alloy, selenium-tellurium alloy, cadmium sulfide, cadmium selenide, cadmium sulphide selenide, mercury sulfide, lead oxide, lead sulfide, the following typical examples You may use the organic pigment shown by.

(1) Azo pigments such as monoazo pigments, polyazo pigments, metal complex salt azo pigments, pyrazolone azo pigments, stilbene azo and thiazole azo pigments.

(2) Perylene pigments such as perylene anhydride and perylene imide.

(3) Anthraquinone-based or polycyclic quinone-based pigments such as anthraquinone derivatives, anthanthrone derivatives, dibenzpyrenequinone derivatives, pyranthrone derivatives, violanthrone derivatives and isobiolanthrone derivatives (4) Indigoide pigments such as indigo derivatives and thioindigo derivatives (5) Phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine (6) Carbonium pigments such as diphenylmethane pigments, triphenylmethane pigments, xanthene pigments and acridine pigments (7) Quinoneimines such as azine pigments, oxazine pigments and thiazine pigments Pigments (8) Methine pigments such as cyanine pigments and azomethine pigments (9) Quinoline pigments (10) Nitro pigments (11) Nitroso pigments (12) Benzoquinone and naphthoquinone pigments (13) Naph Ruimido pigments (14) perinone pigments such as bis-benzimidazole derivatives Next, a preferred embodiment of the CGM used in the present invention.

Azo-based example pigment II- (C) Others II-61 X-type metal-free phthalocyanine II-62 τ-type metal-free phthalocyanine II-63 Chloroaluminum phthalocyanine II-64 Titanyl phthalocyanine II-65 Vanadyl phthalocyanine II-66 ε-type copper phthalocyanine II-67 Chloroindium Phthalocyanine As the CGM compound used in the present invention, in addition to the above-exemplified compounds, compounds described in JP-A-60-172045 can be used.

Next, CTM used in the present invention is a compound represented by the general formula [A].

General formula [A] In the formula, R ₁ represents a hydrogen atom or a substituent, R ₂ represents a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, Ar ₁ represents a hydrogen atom, a substituted or unsubstituted phenyl. Represents a group or a substituted or unsubstituted naphthyl group, Ar ₂ represents a substituted or unsubstituted phenylene group or a substituted or unsubstituted naphthylene group, Ar ₃ and Ar ₄ are each a substituted or unsubstituted alkyl group, substituted or It represents an unsubstituted phenyl group or a substituted or unsubstituted naphthyl group, and n represents 0 or 1.

Examples of the substituent represented by R ₁ include an alkyl group (eg, methyl group, propyl group, butyl group, octyl group, etc.), an alkoxy group (eg, methoxy group, propoxy group, butoxy group, etc.), an aryloxy group (eg, phenoxy group). Etc.), halogen atom (eg chlorine atom)
Etc. The alkyl group represented by R ₂ is, for example, a methyl group or an ethyl group, and the aryl group is, for example, a phenyl group or a naphthyl group.

When each group represented by R ₁ , R ₂ and Ar _{1 to} Ar ₄ has a substituent, examples of the substituent include an alkyl group, an aryl group, an alkoxy group and a halogen atom.

Typical examples of CTM used in the present invention are shown below, but the present invention is not limited to these.

The above CTM compound can be easily synthesized, for example, according to the method described in JP-A-58-198425.

Although 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, any one of the CTL, CGL, the single-layer photosensitive layer or the OCL as the surface layer, or a plurality of layers One or more electron-accepting substances may be incorporated for the purpose of improving sensitivity, reducing residual potential or reducing fatigue during repeated use.

The electron accepting substance that can be used in the photoreceptor of the present invention includes
For example, succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrachlorophthalic anhydride,
Tetrabromophthalic anhydride, 3-nitrophthalic anhydride,
4-nitrophthalic anhydride, pyromellitic dianhydride, mellitic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-dinitrobenzene, 1,3,5-trinitrobenzene, paranitrobenzonitrile, Picryl chloride, quinone chlorimide, chloranil, bulmannyl, 2-methylnaphthoquinone, dichlorodicyanoparabenzoquinone, anthraquinone, dinitroanthraquinone, trinitrofluorenone, 9-fluorenylidene [dicyanomethylene malonodinitrile], polynitro-9-fluorenylidene- [dicyano Methylene malonodinitrile], picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, 3,5-dinitrobenzoic acid, pentafluorobenzoic acid, 5-nitrosalicylic acid,
Examples include 3,5-dinitrosalicylic acid and phthalic acid.

Further, silicone oil may be present as a surface modifier. Further, an ammonium compound may be contained as a durability improver.

Examples of the binder resin 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, polyhydroxystyrene resin, polyester resin,
Alkyd resin, polycarbonate resin, silicone resin, addition polymerization type resin such as melamine resin, polyaddition type resin,
Polycondensation type resins and copolymer resins containing two or more of repeating units of these resins, such as vinyl chloride-vinyl acetate copolymer resins and vinyl chloride-vinyl acetate-maleic anhydride copolymer resins. Insulating resin, poly-N
-Polymer organic semiconductors such as vinylcarbazole.

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, as the conductive support for supporting the photosensitive layer, a metal plate such as aluminum or nickel, a metal drum or a metal foil, a plastic film on which aluminum, tin oxide, indium oxide or the like is deposited or a paper coated with a conductive substance is used. , Films such as plastics or drums can be used.

CGL is a method of vacuum-depositing the above-mentioned CGM on the above support,
It can be provided by a method in which CGM is dissolved or dispersed in a suitable solvent alone or together with a suitable binder resin, and the resulting solution is dried.

For CGM dispersion, ball mill, homomixer, sand mill,
An ultrasonic disperser, an attritor, or the like is used.

Examples of the solvent used for forming 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 etc. can be mentioned.

The CGM is preferably 20 parts by weight or more, and particularly preferably 25 to 400 parts by weight, per 100 parts by weight of the binder resin in CGL.

The thickness of the CGL formed as described above is preferably
The thickness is 0.01 to 10 μm, particularly preferably 0.1 to 5 μm.

The CTL can be formed in the same manner as the above-mentioned CGL, that is, the above-mentioned CTM, that is, alone or by dissolving and dispersing with the above-mentioned binder resin, and coating and drying.

The CTM is preferably 20 to 200 parts by weight, and particularly preferably 30 to 150 parts by weight, per 100 parts by weight of the binder resin in CTL.

The film thickness of the CTM formed is preferably 5 to 50 μm, particularly preferably 5 to 30 μm.

The binder of the protective layer provided as necessary in the present invention has a volume resistance of 10 ⁸ Ωcm or more, preferably 10 ¹⁰
A transparent resin of Ω · cm or more, more preferably 10 ¹³ Ω · cm or more is used. The binder may be a resin that is cured by light or heat. 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, There are polyester resins, alkyd resins, melamine resins, photocurable cinnamic acid resins and the like, or copolymerization or cocondensation resins of these, and all of the light or thermosetting resins used for 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 workability and physical properties (preventing cracks, imparting flexibility, etc.). Examples of such a thermoplastic resin include polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, epoxy resin, butyral resin, polycarbonate resin, silicone resin, or copolymer resin thereof, such as vinyl chloride-vinyl acetate resin. There are polymer resins, vinyl chloride-vinyl acetate-maleic anhydride copolymer resins, polymer organic semiconductors such as poly-N-vinylcarbazole, and all of the thermoplastic resins used for electrophotographic materials can be used. .

Further, the protective layer may contain an electron accepting substance,
In addition, if necessary, it may contain an ultraviolet absorber or the like for the purpose of protecting the CGM, and it is dissolved in a solvent together with the binder, and then coated by, for example, dip coating, spray coating, blade coating, roll coating, etc., and dried to 2 μm or less. ,
It is preferably formed to a layer thickness of 1 μm or less.

[Examples] Hereinafter, the present invention will be described with reference to Examples, but the embodiments of the present invention are not limited thereto.

On a conductive support made of a polyester film laminated with aluminum foil, vinyl chloride-vinyl acetate-
A 0.1 μm-thick intermediate layer made of a maleic anhydride copolymer (S-REC MF-10, manufactured by Sekisui Chemical Co., Ltd.) was formed.

Next, 40 g of 4,10-dibromoanthanthrone (II-73) sublimated as CGM was pulverized in a porcelain ball mill at 40 rpm for 24 hours, and Panlite L-1250 (Sekisui Chemical Co., Ltd.) 20 g
And 1,2-dichloroethane (1300 ml) were added, and the mixture was further dispersed for 24 hours to obtain a CGL coating liquid. This was coated on the intermediate layer to provide CGL having a film thickness of 1 μm.

Then, CTM (III-61) 7.5 g, Panlite L-1250 10 g and compound (HP-117) 0.150 g were added to 1,2-dichloroethane 80.
The solution dissolved in ml is applied on the CGL and the thickness of C is 15μm.
TL was formed to prepare a photoconductor sample No. 1 of the present invention.

Further, Sample Nos. 2 to 4 were prepared in the same manner as Sample No. 1 except that the combination of CTM and the added compound in CTL in Sample No. 1 was changed as shown in the table.

In addition, the sample N was placed on a conductive support made of 100 μm thick polyethylene terephthalate vapor-deposited with aluminum.
The same intermediate layer as in o.1 was formed, and then 1.5 g of the bisazo compound (II-68) was used as CGM in a ball mill in 100 ml of a 1,2-dichloroethane / monoethanolamine (1000/1 volume ratio) mixed solvent. The time-dispersed dispersion is applied on the above intermediate layer, dried sufficiently to provide 0.3 μm thick CGL, and then
As CTM, styryl compound (III-11) 11.25 g, Panlite L-1250 (above) 15 g and compound (HP-35) 0.225 g
Was dissolved in 100 ml of 1,2-dichloroethane to prepare a solution of CGL
It was coated on the surface and sufficiently dried to form a CTL having a thickness of 15 μm, and a photoconductor sample No. 5 of the present invention was prepared.

Further, Sample No. 6 was prepared in the same manner as Sample No. 5 except that the additive compound HP-35 in CTL was excluded.

In addition, τ-type metal-free phthalocyanine obtained by a known method
II-62 1.0 g of polyvinyl butyral (S-REC BL-
S: Sekisui Chemical Co., Ltd.) 2.0 g, 1,2-dichloroethane 98 ml
It was added to the mixed liquid consisting of and dispersed by an ultrasonic disperser. The dispersion is applied to a conductive support made of a polyester film laminated with aluminum foil so that the film thickness after drying is 0.3 μm, and dried to form CGL,
A CTL similar to Sample No. 1 was formed on this CGL except that the compounds in CTM and CTL were changed as shown in the table.
Was produced.

Sample No. 8 was prepared in the same manner as Sample No. 7 except that compound HP-79 in CTL was removed.

Sample Nos. 9 and 10 were prepared in the same manner as Sample No. 1 except that the compounds in CTM and CTL were changed as shown in the table.

Sample Nos. 11 to 16 were prepared in the same manner as Sample No. 5 except that the added compounds in CGM, CTM and CTL were changed as shown in the table.

In addition, a vinyl chloride-vinyl acetate-maleic anhydride copolymer (S-REC MF-10, Sekisui Chemical Co., Ltd.) intermediate thickness of 0.1 μm is formed on a conductive support made of a polyester film laminated with aluminum foil. Form a layer, then CTM (III-61) / polycarbonate resin (Panlite L-1250, Teijin Chemicals) = 75/100 (weight ratio)
1,2-dichloroethane solution containing 16.5% by weight of diazonium was dip-coated on the intermediate layer and dried to obtain a CTL having a thickness of 15 μm.

Next, 4,10-dibromoanthanthrone (II-73) / Panlite L-1250 = 50/100 (weight ratio) sublimated as CGM was crushed with a ball mill for 24 hours to give 9% by weight.
CTM (III-61) was added to Panrite L-1250 in an amount of 75% by weight and 1,2-dichloroethane added to the liquid dispersed in a ball mill for 24 hours, and the compound of the present invention (HP-79) was added to CTM. 3 wt% was added. Monochlorobenzene was added to this dispersion to obtain monochlorobenzene / 1,2-dichloroethane =
What was prepared so as to have a volume ratio of 3/7 was formed on the CTL by spray coating to form a CGL having a thickness of 5 μm to obtain a photoreceptor sample No. 17 of the present invention having a photosensitive layer having a laminated structure. .
Further, Sample No. 18 was prepared in the same manner as Sample No. 17 except that the compound HP-79 in CGL was removed.

(Evaluation method) The photoconductor prepared above was manufactured by Konishi Rokusha Kogyo Co., Ltd. U-
Set on a modified 1550MR machine, and made by Trek at the position of the developing device.
Set 360 type surface potentiometer performs continuous 10000 copies in a normal A4 copy mode, to measure the residual potential V _R. In the table, ΔV _R is the change amount after 10,000 copies, and the value in () is the initial VR value. ▲ E ⁶⁰⁰ ₁₀₀ ▼ shows the amount of light when the black paper with OD = 1.3 is placed on the original and the white surface of the photoconductor surface potential Vs = 600V and OD = 0.0 is set to Vs = 100V. Dete
ctor Technology) photometer S350 LINEAR / LOG OPT
It was measured by IMETER. The charging potential V _A was measured by a method in which a copying process was performed with the above-mentioned machine (U-Bix 1550MR) in a state where the exposure lamp was turned off, and the surface potential of the photoconductor at the developing position at that time was measured. ΔV _{A in the} table is V _A before 10,000 copies and the amount of potential decrease after 10,000 copies. ()
The value inside is the value of V _A before 10,000 copies.

Sample Nos. 17 to 18 were evaluated in the same manner as above except that the negative charge was changed to the positive charge. The results are shown in the table below.

From the above results, it is clear that the photoreceptor of the present invention has good charging characteristics even after repeated use, the increase in residual potential is significantly reduced, and the decrease in charging potential due to repeated use is small.

Sample No. 13 of the present invention was prepared in the same manner as Sample No. 13 except that CTM-1, CTM-2, and CTM-3 in Table A were used in place of III-77 as the photoreceptor sample No. 13 of the present invention. 19-24 were produced.

Sample No. 1 of the present invention was carried out in the same manner as Sample No. 1 except that CTM of CTM-1, CTM-2, and CTM-3 in Table B were used instead of III-61 for the photoreceptor sample No. 1 of the present invention. 25-30 were made.

Sample No. 11 of the present invention was prepared in the same manner as Sample No. 11 except that CTM was replaced with CTM-1, CTM-2 and CTM-3 in Table C instead of III-31. 31-36 were produced.

Evaluation tests were performed on these samples in the same manner as in the above-mentioned examples, and the results are shown in Tables A to C.

For comparison, in Table-A, corresponding samples 13 (invention), 14
(Comparison), in Table-B, corresponding samples 1 (invention) and 2
(Comparison), and in Table-C, corresponding samples 11 (invention) and 12 (comparison) are listed for reference.

As is clear from Table-A to Table-C, the photoreceptor of the present invention has a charging property by using CTM represented by the general formula [A] of the present invention and a compound having a hindered phenol structural unit in combination. It is clear that the increase of the residual potential is reduced, and the decrease of the charging potential due to repeated use is small.

[Effects of the Invention] As described in detail above, according to the electrophotographic photosensitive member of the present invention, it is excellent in environmental resistance, particularly ozone resistance, and has a decrease in charging ability during repeated use, an increase in dark decay, and a decrease in sensitivity. It is possible to remarkably reduce phenomena such as decrease and increase in residual potential, and it is possible to provide an electrophotographic photoreceptor having excellent repeating characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1, 2 and 3 are sectional views showing an embodiment of an electrophotographic photosensitive member of the present invention. 1 ... Support, 2 ... Charge generation layer (CGL) 3 ... Charge transport layer (CTL), 4 ... Photosensitive layer 5 ... Charge generation material (CGM) 6 ... Charge transport material (CTM)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihide Fujimaki 2970 Ishikawa-cho, Hachioji City, Tokyo Inside Konishi Rokusha Shinkogyo Co., Ltd. (56) References JP-A-60-98437 (JP, A) JP-A-60 -129751 (JP, A)

Claims (1)

[Claims] 1. A hindered phenol structure represented by the following general formula [I] in an electrophotographic photosensitive member comprising a conductive substrate and a photosensitive layer containing a compound represented by the following general formula [A]. An electrophotographic photoreceptor comprising a compound having a unit. General formula [A] (In the formula, R ₁ represents a hydrogen atom or a substituent, R ₂ represents a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, Ar ₁ represents a hydrogen atom, a substituted or unsubstituted Represents a phenyl group or a substituted or unsubstituted naphthyl group, Ar ₂ represents a substituted or unsubstituted phenylene group or a substituted or unsubstituted naphthylene group, Ar ₃ and Ar ₄ are substituted or unsubstituted alkyl group, substituted Alternatively, it represents an unsubstituted phenyl group or a substituted or unsubstituted naphthyl group, and n represents 0 or 1.) General formula [I] (In the formula, R ₆ is a branched alkyl group, R ₇ , R ₈ and R ₉ are each a hydrogen atom, a hydroxy group, an alkyl group or an aryl group, and at least two of R ₇ , R ₈ and R ₉ are They may be linked to each other to form a ring, and R ₁₀ represents a hydrogen atom, an alkyl group or an alkylidene group.)