JP2884353B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrophotographic photosensitive member, and more particularly, to an electrophotographic photosensitive member having a photosensitive layer containing a carrier generating substance and a carrier transporting substance.

(Prior art)

Conventionally, selenium, zinc oxide,
Those having a photosensitive layer containing an inorganic photoconductor such as cadmium sulfide or silicon as a main component have been widely known.
However, these are not always satisfactory in characteristics such as thermal stability and durability, and also have problems in production and handling.

On the other hand, a photoconductor having a photosensitive layer containing an organic photoconductive compound as a main component is relatively easy to manufacture, inexpensive, easy to handle, and generally has a higher thermal conductivity than a selenium photoconductor. It has many advantages such as excellent stability, and such organic photoconductive compounds include poly-
N-vinylcarbazole is best known, and photoreceptors having a photosensitive layer mainly composed of a charge transfer complex formed from this and a Lewis acid such as 2,4,7-trinitro-9-fluorenone have already been developed. Has been put to practical use.

On the other hand, there is known a photoreceptor having a function-separated type photosensitive layer of a laminated type or a single layer type in which a carrier generating function and a carrier transporting function of a photoconductor are respectively assigned to separate substances, for example, amorphous selenium. A photoreceptor having a photosensitive layer composed of a carrier generating layer composed of a thin layer and a carrier transporting layer containing poly-N-vinylcarbazole as a main component has already been put to practical use.

However, poly-N-vinylcarbazole lacks flexibility, its film is hard and brittle, and it is easy to cause cracking and film peeling, and the photoreceptor using this has poor durability, and a plasticizer is added. If this defect is remedied, the residual potential increases when the electrophotographic process is performed, and the residual potential is accumulated with repeated use, so that the fog gradually increases and the copied image is damaged.

In addition, since low-molecular organic photoconductive compounds generally do not have a film-forming ability, they are used in combination with an appropriate binder, and the physical properties or photosensitivity of the film are controlled to some extent by selecting the type and composition ratio of the binder. Although it is preferable from the point of view, the kind of the organic photoconductive compound having high compatibility with the binder is limited. Actually, there are few types of binders that can be used for forming a photosensitive layer, particularly a photosensitive layer of an electrophotographic photosensitive member.

For example, 2,5-bis (p described in U.S. Pat. No. 3,189,447
-Diethylaminophenyl) -1,3,4-oxadiazole has low compatibility with binders commonly used as materials for the photosensitive layer of the electrophotographic photoreceptor, such as polyester and polycarbonate, and is necessary for improving electrophotographic properties. When the photosensitive layer is formed by mixing at a ratio of, the oxadiazole crystals are deposited at a temperature of 50 ° C. or higher, and there is a disadvantage that the electrophotographic properties such as charge holding power and sensitivity are reduced.

On the other hand, the diarylalkane derivative described in U.S. Pat. No. 3,820,989 has a small compatibility problem with respect to a binder, but has low stability to light, and is repeatedly charged and exposed. When used in the photosensitive layer, there is a disadvantage that the sensitivity of the photosensitive layer gradually decreases.

U.S. Pat. No. 3,274,000 and JP-B-47-36428 describe different types of phenothiazine derivatives, but all have the disadvantages of low photosensitivity and low stability upon repeated use.

The stilbene compounds described in JP-A-58-65440 and JP-A-58-198043 have relatively good charge holding power and sensitivity, but are not satisfactory in durability when used repeatedly.

As a matter of fact, a carrier transporting material having practically satisfactory characteristics for producing an electrophotographic photosensitive member has not been found yet.

[Object of the invention]

An object of the present invention is to provide a photosensitive member having high sensitivity.

Another object of the present invention is to provide an electrophotographic photosensitive member having high sensitivity and low residual potential.

Another object of the present invention is to provide a photoreceptor for repetitive transfer electrophotography in which charging, exposure, development, and transfer steps are repeatedly performed. An object of the present invention is to provide an electrophotographic photosensitive member having excellent durability.

[Means for solving the problem]

As a result of intensive studies for the above purpose, it has been found that an electrophotographic photoreceptor containing at least one compound represented by the following general formula [I] has excellent utility.

General formula [I] In the formula, Ar ¹ and Ar ² are an aryl group which may have a substituent, Ar
³ represents an aryl group or an aralkyl group which may have a substituent, Ar ⁴ represents an aryl group which may have a substituent, and Ar ⁵ represents an arylene group which may have a substituent. R
¹ represents a hydrogen atom, an alkyl group, or an aryl group which may have a substituent, and R ² represents a halogen atom, a halogen atom, an alkyl group, or an alkoxy group. n represents an integer of 1 or 2.

More specifically, alkyl groups of Ar ^{1 to} Ar ⁴ include methyl, ethyl, propyl, isopropyl, butyl, isobutyl and t-butyl, aralkyl groups such as benzyl and phenethyl, and aryl groups such as phenyl and naphthyl. No.

Examples of the alkyl group for R ¹ include methyl, ethyl, propyl,
Aryl groups include phenyl, naphthyl, etc., such as isopropyl, butyl, isobutyl and t-butyl. Examples of the arylene group of Ar ⁵ include phenylene and naphthylene.

R ² alkyl groups include methyl, ethyl, propyl, and butyl groups; halogen atoms include fluorine, chlorine, bromine, and iodine atoms; and alkoxy groups include methoxy, ethoxy, propoxy, and butoxy groups. And the like.

Next, specific examples of the compound represented by the general formula [I] will be illustrated.

Synthesis example (exemplified compound (45)) 3.0 g of an aldehyde compound represented by the following formula 4.7 g of the phosphonate compound was dissolved in 50 ml of N, N dimethylformamide (DMF). Add 20 ml of DMF and potassium-t
1.8 g of butoxide were added dropwise to the stirring.

Thereafter, the mixture was reacted at room temperature for 5 hours, extracted with toluene and washed with water. The solvent was removed and purification was performed by silica gel-column chromatography using toluene-hexane to obtain 3.9 g of the desired product. 72.3% yield.

The parent peak (M ⁺ ) of the target compound was found to be 542 (C ₄₀ H ₃₄ N ₂ ) by FD-mass measurement.

Various structures are known for the structure of the electrophotographic photoreceptor, and the electrophotographic photoreceptor of the present invention can take any of these forms.

Normally, the configuration is as shown in FIGS. FIGS. 1 and 2 show a photosensitive structure comprising a laminate of a carrier generating layer 2 mainly containing a carrier generating substance and a carrier transporting layer 3 mainly containing a carrier transporting substance on a conductive support 1. Layer 4 is provided.

As shown in FIGS. 3 and 4, the photosensitive layer 4 may be provided via an intermediate layer 5 provided on a conductive support. Thus, when the photosensitive layer 4 has a two-layer structure, a photosensitive member having the best electrophotographic characteristics can be obtained. In the present invention, as shown in FIGS. 5 and 6, a photosensitive layer 4 formed by dispersing the carrier generating substance 7 in a layer 6 containing a carrier transporting substance as a main component is provided on the conductive support 1. It may be provided directly or via the intermediate layer 5. In the present invention,
After FIG. 4, a protective layer 8 may be provided as the outermost layer.

The following are examples of the carrier generating substance used in the carrier generating layer of the photosensitive layer according to the present invention.

(1) Azo dyes such as monoazo dyes, disazo dyes and trisazo dyes (2) Perylene dyes such as perylene anhydride and perylene imide (3) Indigo dyes such as indigo and thioindigo (4) Anthraquinone, pyrenequinone And polycyclic quinones such as flavanthrones (5) quinacridone dyes (6) bisbenzimidazole dyes (7) indathrone dyes (8) squarylium dyes (9) cyanine dyes (10) azurenium dyes (11) Triphenylmethane pigments (12) Amorphous silicon (13) Phthalocyanine pigments such as metal phthalocyanines and metal-free phthalocyanines (14) Selenium, selenium-tellurium, selenium-arsenic (15) CdS, CdSe (16) pyrylium salts Dyes, thiapyrylium salt dyes, etc., alone or in combination of two or more. It can be used as a mixture.

Since the compound of the present invention has no coating forming ability by itself, a photosensitive layer is formed by combining various binders.

Any binder can be used here, but it is preferable to use a high molecular polymer which is hydrophobic, has a high dielectric constant, and forms an electrically insulating film. Examples of such a high-molecular polymer include the following, but are not limited thereto.

(P-1) Polycarbonate (P-2) Polyester (P-3) Methacrylic resin (P-4) Acrylic resin (P-5) Polyvinyl chloride (P-6) Polyvinylidene chloride (P-7) Polystyrene (P -8) Polyvinyl acetate (P-9) Styrene-butadiene copolymer (P-10) Vinylidene chloride-acrylonitrile copolymer (P-11) Vinyl chloride-vinyl acetate copolymer (P-12) Vinyl chloride-acetic acid Vinyl-maleic anhydride copolymer (P-13) Silicone resin (P-14) Silicone-alkyd resin (P-15) Phenol formaldehyde resin (P-16) Styrene-alkyd resin (P-17) Poly-N- Vinyl carbazole (P-18) Polyvinyl butyral (P-19) Polyvinyl formal These binder resins may be used alone or as a mixture of two or more. It can be.

Examples of the solvent for forming the carrier generation layer and the transport layer according to the present invention include N, N-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, 1,2-dichloroethane, and 1,2. -Dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethane, dichloromethane, tetrahydrofuran, dioxane, methanol, ethanol, isopropanol, ethyl acetate, ethyl acetate, butyl acetate, dimethyl sulfoxide , Methyl cellosolve, etc., and can be used as a mixture.

When the photoreceptor of the present invention has a laminated structure, the weight ratio of binder: carrier generating substance: carrier transporting substance in the carrier generating layer is preferably from 0 to 100: 1 to 500: 0 to 500.

If the content of the carrier-generating substance is less than this, the photosensitivity is low and the residual potential is increased, and if it is more than this, the dark decay and the receiving potential are reduced.

Further, the carrier transporting substance is preferably 20 to 200 wt per 100 parts by weight (expressed as wt) of the binder resin in the carrier transport layer,
Particularly preferably, it is 30 to 150 wt.

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

The thickness of the carrier transporting layer formed is preferably 5 to 50 μm, particularly preferably 5 to 30 μm.

On the other hand, when the photoconductor of the present invention has a single-layer function-separated structure,
The weight ratio of binder: carrier generating substance: carrier transporting substance in the photosensitive layer is preferably from 0 to 100: 1 to 500: 1 to 500, and the thickness of the formed photosensitive layer is preferably from 5 to 50 μm, particularly preferably from 5 to 50 μm. 3030 μm.

As the conductive support used in the electrophotographic photoreceptor of the present invention, a metal plate including an alloy, a metal drum or a conductive polymer, a conductive compound such as indium oxide or an alloy including aluminum, palladium, gold, etc. Conductive paper by applying, depositing or aminating a thin metal layer,
Plastic films and the like.

As the binder used for the intermediate layer, the protective layer, and the like, those described above for the carrier generation layer and the carrier transport layer can be used.Other polyamide resins, nylon resins, ethylene-vinyl acetate copolymers, Ethylene resins such as ethylene-vinyl acetate-maleic anhydride copolymer and ethylene-vinyl acetate-methacrylic acid copolymer, polyvinyl alcohol, and cellulose derivatives are effective.

Organic amines can be added to the photosensitive layer of the invention for the purpose of improving the carrier generation function of the carrier generation substance. Among the organic amines, it is particularly preferable to add a secondary amine.

Further, the photosensitive layer may contain a deterioration inhibitor such as an antioxidant and a light stabilizer for the purpose of improving storage stability, durability and environmental resistance. Compounds used for such purposes include, for example, chromanol derivatives such as tocophenol and their etherified or esterified compounds, polyarylalkane compounds, hydroquinone derivatives and their mono- and dietherified compounds, benzophenone derivatives, benzotriazole derivatives, A thioether compound, a phosphonate ester, a phosphite ester, a phenylenediamine derivative, a phenol compound, a hindered phenol compound, a linear amine compound, a cyclic amine compound, a hindered amine compound, and the like are effective. Specific examples of particularly effective compounds include “IRGANOX 10
10, "IRGANOX 565" (manufactured by Ciba-Geigy), "Sumilyzer BHT", "Sumilyser MDP" (manufactured by Sumitomo Chemical Co., Ltd.), etc., hindered phenol compounds, "Sanol LS-2626", "Sanol LS-622LD" ”(Manufactured by Sankyo)
And the like.

In the present invention, the carrier generating layer may contain one or more kinds of electron-accepting substances for the purpose of improving sensitivity, reducing residual potential or reducing fatigue during repeated use, and the like.

Electron accepting substances that can be used here include
For example, succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrachlorophthalic anhydride,
Tetrabromophthalic anhydride, 3-nitrophthalic anhydride,
4-nitrophthalic anhydride, pyromellitic anhydride, melitic anhydride, tetracyanoethylene, tetracyamiquinodimethane, o-dinitrobenzene, m-dinitrobenzene, 1,3,5-trinitrobenzene, paranitrobenzonitrile, Piclink chloride, quinone chlorimide, chloranil, bulmanil, dichlorodicyanoparabenzoquinone, anthraquinone, dinitroanthraquinone, 2,7
-Dinitrofluorenone, 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, 9-fluorenylidenemalonodinitrile, polynitro-9-fluorenylidene-malonodinitrile, picric acid, o-nitrobenzoate Acids, p-nitrobenzoic acid, 3,5-dinitrobenzoic acid, pentafluorobenzoic acid, 5-nitrosalicylic acid, 3,5-dinitrosalicylic acid, phthalic acid, melitic acid, and other compounds having a high electron affinity Can be.

The amount of the electron-accepting substance to be added is as follows: carrier generating substance: electron-accepting substance = 100: 0.01 to 200, preferably 100:
0.1 to 100.

The electron accepting substance may be added to the carrier transport layer.
The amount of the electron accepting substance added to such a layer is carrier transporting substance: electron accepting substance = 100: 0.01 to 100, preferably 100: 0.1 to 50 by weight ratio.

In addition, the photoreceptor of the present invention may further contain, if necessary, an ultraviolet absorber or the like for the purpose of protecting the photosensitive layer, or may contain a dye for correcting color sensitivity.

The electrophotographic photoreceptor of the present invention is configured as described above, and as is clear from the examples described later, charging characteristics,
It has excellent sensitivity characteristics and image forming characteristics. In particular, it has little fatigue deterioration even when used repeatedly, and has excellent durability.

Further, the electrophotographic photoreceptor of the present invention is not limited to an electrophotographic copying machine, but also includes a laser, a cathode ray tube (CRT), a light emitting diode (LE).
It can be widely used in application fields such as photoconductors of printers using D) as a light source.

〔Example〕

Hereinafter, the present invention will be described specifically with reference to Examples.
This does not limit the embodiments of the present invention.

Example 1 A vinyl chloride-vinyl acetate-maleic anhydride copolymer "ESREC MF-10" (manufactured by Sekisui Chemical Co., Ltd.) on a conductive support obtained by evaporating aluminum on a polyester film.
A 0.05 μm thick intermediate layer made of dibromoanthranthrone “Monolite Red 2Y” (CI No. 5
1.5 g of polycarbonate “Panlite L-1250” (manufactured by Teijin Chemicals) was dissolved in a dispersion obtained by adding 1 g of 9300 ICI) to 30 ml of 1,2-dichloroethane and dispersing with a ball mill, and thoroughly mixed. The coating solution was applied so that the film thickness after drying was 2 μm, to form a carrier generation layer.

On top of this, 7 g of the exemplified compound (4), 10 g of polycarbonate “Z-200” (Mitsubishi Gas Chemical) and “IRGANOX
1010 "is added to the carrier transporting substance at a concentration of 2%, and a solution obtained by dissolving in 80 ml of 1,2-dichloroethane is dried to have a thickness of 20 μm
Thus, a carrier transport layer was formed to prepare a photoreceptor of the present invention.

The photoreceptor thus obtained was manufactured by Kawaguchi Electric Co., Ltd.
The following characteristics were evaluated using EPA-8100. Charge voltage -6K
After charging for 5 seconds with V, the photosensitive member was left in the dark for 5 seconds, and then irradiated with a halogen lamp light so that the illuminance on the surface of the photoreceptor became 2 lux, thereby obtaining the initial surface potential V _A and the half-exposure amount E1 / 2.

Further, the same measurement was repeated 1000 times. Table 1 shows the results
As shown in FIG.

Examples 2 to 6 Photoconductors were prepared and measured in the same manner as in Example 1 except that the exemplified compounds shown in Table 2 below were used instead of the exemplified compound (4). Further, the same measurement was repeated 3000 times. still,
The types of the compounds in Table 2 are as follows.

As is clear from Table 2, the exemplified compound (1
1) and (15) are more sensitive to the comparative compound (18).
In addition, although the initial sensitivity itself of the exemplified compound (24) and the exemplified compound (31) are at the same level as that of the comparative compound (18), it can be seen that there is little change in sensitivity upon repetition and little change in charging potential. The signs are evident even after 1000 repetitions,
It becomes clearer if the repetition is extended up to 3000 times.

Comparative Example (1) A comparative photoconductor was prepared in the same manner as in Example 1, except that the following compound was used as a carrier transporting substance.

The comparative photoreceptor was measured in the same manner as in Example 1, and the results shown in Table 3 were obtained.

In addition, the carrier transport material has poor compatibility, and crystals have been precipitated after coating.

Example 7 On a conductive support obtained by evaporating aluminum on a polyester film, a polyamide resin "A-70" (manufactured by Toray Industries, Inc.)
An intermediate layer having a thickness of 0.1 μm was formed.

2 g of a bisazo pigment having the above structure and 2 g of a polycarbonate resin `` Panlite L-1250 '' were mixed with 1,2-dichloroethane 9
0 ml, and dispersed by a sand grinder for 8 hours.
This dispersion was applied onto the intermediate layer such that the thickness after drying was 0.2 μm.

Using Exemplified Compound (7) as a carrier transporting substance,
A photoreceptor was prepared in the same manner as in Example 1, except that 2% of the deterioration inhibitor "IRGANOX 1010" was added to the carrier transporting substance. The same measurement as in Example 1 was performed on this photoreceptor, and the results in Table 4 were obtained.

Examples 8 to 12 Photoconductors were prepared in the same manner as in Example 7, except that the exemplified compounds shown in Table 5 below were used instead of the exemplified compound (7).
It was measured. Further, the same measurement was repeated 3000 times.
The types of the compounds shown in Table 5 are as follows.

As is clear from Table 5, the exemplified compound (3
4) and (45) have good sensitivity to the comparative compound (12).
Further, although the initial sensitivity itself of the exemplified compound (23) and the exemplified compound (30) is at the same level as that of the comparative compound (12), the variation of the sensitivity upon repetition is smaller than that of the comparative compound (12), and the charging potential is small. Is small. The symptoms are evident even after 1000 iterations, but it becomes clearer if you extend the iterations to 3000.

Comparative Example (2) A comparative photoconductor was prepared in the same manner as in Example 7, except that the following compound was used as a carrier transporting substance.

This photoreceptor was measured in the same manner as in Example 1, and the results in Table 6 were obtained.

As in Comparative Example (1), crystals of the applied carrier transporting material were precipitated.

Example 13 An intermediate layer having a thickness of 0.2 μm and made of a polyamide resin “CM 8000” (manufactured by Toray Industries, Inc.) was provided on a conductive support obtained by evaporating aluminum on a polyester film.

2 g of titanyl phthalocyanine having an X-ray diffraction spectrum shown in FIG. 7 and 20 g of a silicone resin "KR-5240, 15% xylene-butanol solution" (manufactured by Shin-Etsu Chemical Co., Ltd.) were dispersed in 100 ml of isopropyl alcohol using a sand mill, The thickness of this dispersion after drying on the intermediate layer is 0.2 μm.
It was applied so that Next, 7 g of the exemplary compound (46) as a carrier transporting substance and polycarbonate "Z-20"
0 "and 10 g were dissolved in 80 ml of 1,2-dichloroethane. This solution was applied so that the film thickness after drying became 20 μm, and a carrier transport layer was formed.

This photoreceptor was measured in the same manner as in Example 1, and the results in Table 7 were obtained.

Example 14 An intermediate layer having a thickness of 0.2 μm made of a thylene-vinyl acetate-methacrylic acid copolymer resin “ELVACS 4260” (manufactured by Mitsui-Dipon Chemical Co., Ltd.) was formed on an aluminum drum.

Exemplary compound (41) as a carrier transporting material of the present invention
A solution of 1 g and 1.5 g of polyester resin "Byron 200" (manufactured by Toyobo Co., Ltd.) in 10 ml of 1,2-dichloroethane was applied on the intermediate layer, and after drying, a carrier transport layer having a thickness of 15 μm was formed. .

On the other hand, 1 g of titanyl phthalocyanine having an X-ray diffraction spectrum shown in FIG. 7 as a carrier-generating substance, 3 g of polycarbonate "Panlite L-1250" (manufactured by Teijin Chemicals Ltd.) as a binder resin, and 15 m of monochlorobenzene as a dispersion medium
After 35 ml of l, 1,2-dichloroethane was dispersed using a ball mill, the exemplary compound (41) was further added as a carrier transporting substance at a ratio of 75 wt% to the binder resin. The dispersion thus obtained was applied on the carrier transport layer by a spray coating method to form a film having a thickness of 2.
A μm carrier generation layer was formed.

The photoreceptor thus obtained was evaluated in the same manner as in Example 11 except that the charging polarity was set to a positive polarity.

To _{V A = 1330 (V) E} 1/2 = 1.2 (lux · sec) Example 15 onto an aluminum drum, vinyl chloride - vinyl acetate -
An intermediate layer having a thickness of 0.1 μm and comprising a maleic anhydride copolymer “S-LEC MF-10” (manufactured by Sekisui Chemical Co., Ltd.) was formed.
On the other hand, 1 g of dibromoanthranthrone `` Monolite Red 2Y '' as a carrier generating substance, after ball milling, 3 g of polycarbonate resin `` Panlite L-1250 '',
A solution of 15 ml of monochlorobenzene and 35 ml of 1,2-dichloroethane was added to perform dispersion. To the obtained dispersion, 2 g of the compound (20) of the carrier transporting substance of the present invention is further added, and the mixture is coated on the intermediate layer by a spray coating method and dried to form a photosensitive layer having a thickness of 20 μm. Formed.

The photoreceptor thus obtained was evaluated in the same manner as in Example 1 except that the charging polarity was set to a positive polarity.

To _{V A = 1370 (V) E} 1/2 = 2.7 (lux · sec) Example 15 onto an aluminum drum, vinyl chloride - vinyl acetate -
A 0.12 μm-thick intermediate layer made of a maleic anhydride copolymer “S-LEC MF-10” (manufactured by Sekisui Chemical Co., Ltd.) was formed.
On the other hand, 1 g of dibromoanthranthrone “Monolite Red 2Y” as a carrier-generating substance, after ball milling, 3 g of polycarbonate resin “Panlite L-1250”,
A dispersion of 15 g of monochlorobenzene and 35 g of 1,2-dichloroethane was added for dispersion. To the obtained dispersion, 2 g of the compound (39) of the carrier transporting substance of the present invention is further added, and the mixture is coated on the intermediate layer by a spray coating method and dried to form a photosensitive layer having a thickness of 20 μm. Formed.

The photoreceptor thus obtained was evaluated in the same manner as in Example 1 except that the charging polarity was set to a positive polarity.

_{V A = 1140 (V) E} 1/2 = 2.7 (lux · sec)

[Brief description of the drawings]

1 to 6 are cross-sectional views of an example of the photoreceptor of the present invention. FIG. 7 is an X-ray diffraction diagram of the titanyl phthalocyanine used in the examples with respect to the Cu-Kα line. DESCRIPTION OF SYMBOLS 1 ... Support, 4 ... Photosensitive layer 2 ... Carrier generating layer, 5 ... Intermediate layer 3 ... Carrier transport layer, 8 ... Protective layer

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-196768 (JP, A) JP-A-63-149652 (JP, A) JP-A-62-79470 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) G03G 5/06 313

Claims (1)

(57) [Claims] 1. An electrophotographic photoreceptor comprising at least one compound represented by the following general formula [I]. General formula [I] [Wherein Ar ¹ and Ar ² are an aryl group which may have a substituent, Ar
³ represents an aryl group or an aralkyl group which may have a substituent, Ar ⁴ represents an aryl group which may have a substituent, and Ar ⁵ represents an arylene group which may have a substituent. R
¹ represents a hydrogen atom, an alkyl group, or an aryl group which may have a substituent, and R ² represents a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group. n represents an integer of 1 or 2. ]