JP3104824B2 - Electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member, and more particularly, to an electrophotographic photosensitive member containing a specific compound in a photosensitive layer.

[0002]

2. Description of the Related Art Conventionally, inorganic materials such as selenium, cadmium sulfide, and zinc oxide have been used as a photoconductive material of a photoreceptor used in an electrophotographic system.
Here, the term "electrophotographic method" generally means that a photoconductive photoreceptor is first charged in a dark place, for example, by corona discharge, and then subjected to image exposure to selectively dissipate the charge of only the exposed portion. An electrostatic latent image is obtained, and the latent image portion is developed and visualized with fine particles (toner) composed of a coloring material such as a dye or a pigment and a binder such as a polymer substance to form an image. This is one of the image forming methods used.

The basic characteristics required of a photoreceptor in such an electrophotographic method include (1) being able to be charged to an appropriate potential in a dark place, (2) being small in electric charge dissipation in a dark place, (3) Charges can be quickly dissipated by light irradiation.

[0004] The above-mentioned inorganic substances have many advantages and also have various disadvantages. For example, selenium, which is widely used at present, satisfies the above conditions (1) to (3), but the production conditions are difficult, the production cost is high, there is no flexibility, and the selenium is processed into a belt shape. It also has drawbacks in that it is difficult to handle, and is sensitive to heat and mechanical shocks, and requires careful handling. Cadmium sulfide and zinc oxide are used as photoreceptors by dispersing them in a resin as a binder.However, due to mechanical defects such as smoothness, hardness, tensile strength, and abrasion resistance, they are repeatedly used as they are. Can not be used.

In recent years, electrophotographic photoreceptors using various organic substances have been proposed to eliminate the disadvantages of these inorganic substances, and some of them have been put to practical use. For example, a photoreceptor comprising poly-N-vinylcarbazole and 2,4,7-trinitrofluoren-9-one (U.S. Pat.
84237), a photoreceptor obtained by sensitizing poly-N-vinylcarbazole with a pyrylium salt-based dye (described in JP-B-48-25658), and a photoreceptor containing an organic pigment as a main component (see JP-B-48-25658). JP-A-47-37543), a photoreceptor containing a eutectic complex composed of a dye and a resin as a main component (described in JP-A-47-10735), and dye-sensitized triphenylamine compound. (US Pat. No. 3,180,730), a photoreceptor using an amine derivative as a charge transport material (JP-A-57-195254), and poly-N-vinylcarbazole and an amine derivative as charge transport materials Photoreceptor used (Japanese Patent Laid-Open No.
55, a photoconductor using a benzidine compound among polyfunctional tertiary amine compounds as a photoconductive material (US Pat. No. 3,265,496, JP-B-39-11546, JP-A-53-27033). ). Although these photoreceptors have excellent properties and are considered to be of high practical value, in electrophotography, considering various requirements for photoreceptors, these requirements are still insufficient. In fact, it is not possible to obtain anything satisfying the above conditions.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a photoreceptor which can solve the above-mentioned various disadvantages of the conventional photoreceptor and can sufficiently satisfy the conditions required in electrophotography. It is in. It is a further object of the present invention to provide an electrophotographic photoreceptor which is easy to manufacture, relatively inexpensive, and has excellent durability.

[0007]

According to the present invention, a photosensitive layer containing at least one pyrene compound represented by the following general formula (I) as an active ingredient is provided on a conductive support. An electrophotographic photoconductor is provided.

Embedded image (In the above formula, R ¹ and R ² represent a halogen atom, a nitro group, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, or a substituted or unsubstituted phenyl group. R ³ represents a lower alkyl group or an alkoxy group, and l is 0 or 1.
M is an integer of 0 or 1; n is 0 or 1;
Represents an integer of 3. When l, m or n is 2 or more,
R ₁ , R ₂ and R ₃ may be the same or different. X represents a substituted or unsubstituted carbocyclic group or a substituted or unsubstituted heterocyclic group. )

In the present invention, the pyrene compound represented by the general formula (I) (formula 1) to be contained in the photosensitive layer is, for example, a compound represented by the following general formula (II) (formula 2)

Embedded image(In the above formula, R¹, R^TwoIs halogen atom, nitro group, cyano
Group, substituted or unsubstituted alkyl group, substituted or unsubstituted
Substituted alkoxy group or substituted or unsubstituted phenyl
Represents a group and may be the same or different. R^ThreeIs low
Represents an alkyl group or an alkoxy group. l is 0 or 1
An integer of 5, m is 0 or an integer of 1 to 4, n is 0 or 1 to 3,
Represents an integer. When l, m or n is 2 or more, R
₁, R_Two, R _ThreeMay be the same or different
No. ) And an aldehyde compound represented by the following general formula (II)
I)

Embedded image By reacting with a phosphorus compound represented by the following formula:

Next, the pyrene compound represented by formula (I) (formula 1) will be described in more detail. In the general formula (I) (Formula 1), the following can be mentioned as specific examples of R ^{1 to} R ³ or as substituents thereof.

(1) Halogen atom: fluorine, chlorine, bromine and iodine. (2) alkyl groups, preferably C ₁ -C _12, especially C ₁
To C ₉ , more preferably a C _{1 to} C ₄ linear or branched alkyl group, and these alkyl groups are furthermore a fluorine atom, a hydroxyl group, a cyano group, a C _{1 to} C ₄ alkoxy group,
It may contain a phenyl group substituted with a phenyl group, a halogen atom, a C ₁ -C ₄ alkyl group or a C ₁ -C ₄ alkoxy group. Specifically, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a t-butyl group,
s-butyl group, n-butyl group, i-butyl group, trifluoromethyl group, 2-hydroxyethyl group, 2-cyanoethyl group, 2-ethoxyethyl group, 2-methoxyethyl group, benzyl group, 4-chlorobenzyl Group, 4-methylbenzyl group, 4-methoxybenzyl group, 4-phenylbenzyl group and the like. (3) alkoxy group (—OR ⁶ ); R ⁶ represents an alkyl group defined in (2). Specifically, methoxy, ethoxy, n-propoxy, i-propoxy, t-butoxy, n-butoxy, s-butoxy, i-butoxy, 2-hydroxyethoxy, 2-cyano Examples include an ethoxy group, a benzyloxy group, a 4-methylbenzyloxy group, and a trifluoromethoxy group. (4) Aryloxy group: Examples of the aryl group include a phenyl group and a naphthyl group. It may contain a C ₁ -C ₄ alkoxy group, a C ₁ -C ₄ alkyl group or a halogen atom as a substituent. Specifically, a phenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group,
-Methylphenoxy group, 4-methoxyphenoxy group, 4
-Chlorophenoxy group, 6-methyl-2-naphthyloxy group and the like.

(5) alkylthio group (—SR ⁷ ), the following phenylthio group

Embedded imageR⁸Represents an alkyl group defined in (2). Specifically
Is a methylthio, ethylthio, phenylthio, p-
And a methylphenylthio group. Represents an alkyl group or an aryl group,
Are, for example, phenyl, biphenylyl or naph
Butyl groups, which are C₁~ C_FourAn alkoxy group of
C₁~ C_FourWith an alkoxy group or a halogen atom as a substituent
May be contained. R₉And R_TenCan form a ring together
good. And form a ring together with the carbon atom on the aryl group.
You may. ) Specifically, an amino group, diethylamino
Group, N-methyl-N-phenylamino group, N, N-diff
Phenylamino group, N, N-di (p-tolyl) amino
Group, dibenzylamino group, piperidino group, morpholino
And a urolidyl group. (7) a methylenedioxy group or a methylenedithio group
An alkylenedioxy group or an alkylenedithio group,Represents a kill group. Specifically, a methoxycarbonyl group,
An ethoxycarbonyl group and the like can be mentioned. (9) Cyano group (-CN) (10) Nitri group (-NO_Two(11) The following phenyl group

Embedded image R ¹² represents a hydrogen atom or a substituent defined in (1) to (10). For example, phenyl group, tolyl group, methoxyphenyl group, benzylphenyl group, chlorophenyl group,
Examples include a 3,4-methylenedioxyphenyl group.

Specific examples of the carbocyclic or heterocyclic ring of X include fluorene, cyclopentadiene, cyclohexadiene, cyclohexene, cyclopentene, indene, 2,3-diphenylindene, 5H-dibenzo [a, d] cycloheptene, , 11-dihydro-5
H-dibenzo [a, d] cycloheptene, xanthene,
Thioxanthene and the like. These rings may have the above substituents.

Hereinafter, general formula (I) used in the present invention will be described.
Representative examples of the compound represented by the following formula (1) are shown.

[Table-1 (1)]

Embedded image

[Table 1- (2)]

[Table 1- (3)]

In the photoreceptor of the present invention, one or more of the above pyrene compounds are used in the photosensitive layer 2 (2 ′, 2 ″, 2 ′ ″).
Or 2 ″ ″), but can be used as shown in FIG. 1, FIG. 2, FIG. 3, FIG. 4, or FIG. 5 depending on the application of these pyrene compounds.

The photoreceptor in FIG. 1 has a conductive support 1 on which a photosensitive layer 2 made of a pyrene compound, a sensitizing dye and a binder (binder resin) is provided. The pyrene compound here acts as a photoconductive substance, and the generation and transfer of charge carriers required for light decay are performed via the pyrene compound. However, since the pyrene compound has little absorption in the visible region of light, it is necessary to sensitize by adding a sensitizing dye having absorption in the visible region for the purpose of forming an image with visible light. .

The photoreceptor shown in FIG. 2 is provided with a photosensitive layer 2 'in which a charge generating substance 3 is dispersed in a charge transport medium 4 comprising a pyrene compound and a binder on a conductive support 1. is there. The pyrene compound here is a binder (or
Together with the binder and the plasticizer) form a charge transport medium, while the charge generating material 3 (a charge generating material such as an inorganic or organic pigment) generates charge carriers. In this case, the charge transport medium 4 is mainly responsible for receiving and transporting charge carriers generated by the charge generating substance 3. And in this photoreceptor, the charge generating substance and the pyrene compound
The basic condition is that the absorption wavelength regions do not mainly overlap in the visible region. This is because it is necessary to transmit light to the surface of the charge generating material 3 in order to efficiently generate charge carriers in the charge generating material 3. The pyrene compound represented by the general formula (I) has almost no absorption in the visible region and generally absorbs light in the visible region, and is particularly effective as a charge transport material when combined with the charge generation material 3 which generates a charge carrier. The feature is that it works.

The photosensitive member shown in FIG. 3 is a photosensitive layer 2 '' comprising a conductive support 1 and a charge generating layer 5 mainly composed of a charge generating substance 3 and a charge transport layer 4 containing a pyrene compound. Is provided. In this photoreceptor, the light transmitted through the charge transport layer 4 reaches the charge generation layer 5 and charge carriers are generated in that region. On the other hand, the charge transport layer 4 receives injection of the charge carriers and transports them. The generation of charge carriers required for light decay is performed by the charge generation material 3,
The transport of the charge carriers is carried out in the charge transport layer 4 (mainly a pyrene compound works). Such a mechanism is the same as that described for the photoconductor shown in FIG.

The photosensitive member in FIG.
And the stacking order of the charge transport layer 4 containing the pyrene compound is reversed, and the mechanism of generation and transport of the charge carriers can be the same as described above. In this case, a protective layer 6 can be provided on the charge generation layer 5 in the fifth manner in consideration of mechanical strength.

To actually prepare the photoreceptor of the present invention, FIG.
In the case of the photoreceptor shown in (1), one or two or more pyrene compounds are dissolved in a solution in which a binder is dissolved, and a solution containing a sensitizing dye is further added thereto. , And dried to form the photosensitive layer 2.

The thickness of the photosensitive layer is 3 to 50 μm, preferably 5 to 20 μm. The amount of the pyrene compound in the photosensitive layer 2 is 30 to 70% by weight, preferably about 50% by weight.
The amount of the sensitizing dye in the photosensitive layer 2 is 0.1%.
-5% by weight, preferably 0.5-3% by weight. As sensitizing charges, brilliant green, Victoria blue B, methyl violet, crystal violet,
Triarylmethane dyes such as Acid Violet 6B, rhodamine B, rhodamine 6G, rhodamine G extra, eosin S, erythrosin, rose bengal, xanthene dyes such as fluorescein, thiazine dyes such as methylene blue, cyanine dyes such as cyanine, Pyrylium dyes such as 2,6-diphenyl-4- (N, N-dimethylaminophenyl) thiapyrylium perchlorate and benzopyrylium salts (described in JP-B-48-25658). These sensitizing dyes may be used alone or in combination of two or more.

Further, in order to produce the photoreceptor shown in FIG. 2, fine particles of the charge generating substance 3 are dispersed in a solution in which one or more pyrene compounds and a binder are dissolved, and this is made into a conductive material. What is necessary is just to apply | coat on the support body 1, and to dry and form the photosensitive layer 2 '.

The thickness of the photosensitive layer 2 'is 3 to 50 μm, preferably 5 to 20 μm. The amount of the pyrene compound in the photosensitive layer 2 'is 10 to 95% by weight, preferably 30 to 95% by weight.
90% by weight, and the amount of the charge generating substance 3 in the photosensitive layer 2 'is 0.1 to 50% by weight, preferably 1 to 20% by weight.
% By weight. Examples of the charge generating substance 3 include inorganic pigments such as selenium, selenium-tellurium, cadmium sulfide, cadmium sulphide-selenium, and α-silicon, and examples of the organic pigments include CI Pigment Blue 25 (color index CI 21180) and CI Pigment Red 41. (CI 21200), CI Acid Red 52 (CI 45100), CI Basic Red 3 (CI45210), azo pigments having a carbazole skeleton (described in JP-A-53-95033), azo pigments having a distyrylbenzene skeleton ( JP-A-53-13
No. 3445), an azo pigment having a triphenylamine skeleton (described in JP-A-53-132347), and an azo pigment having a dibenzothiophene skeleton (JP-A-54-132347).
21728), an azo pigment having an oxadiazole skeleton (described in JP-A-54-12742), and an azo pigment having a fluorenone skeleton (described in JP-A-54-12742).
No. 22834), an azo pigment having a bisstilbene skeleton (described in JP-A-54-17733), and an azo pigment having a distyryloxadiazole skeleton (described in JP-A-54-2129) And azo pigments having a distyrylcarbazole skeleton (JP-A-54-14)
Azo pigments such as C.I. Pigment Blue 16 (CI 74100), such as C.I.
(CI 73410), sea butt die (CI 7
3030), Argo Scarlet B (manufactured by Bayer AG), Indance Scarlet R
(Manufactured by Bayer AG) and the like. These charge generating substances may be used alone or in combination of two or more.

Further, in order to prepare the photoreceptor shown in FIG. 3, a charge-generating substance is vacuum-deposited on the conductive support 1 or more, or a fine particle 3 of the charge-generating substance is dissolved in a binder if necessary. Coating and drying, and further, if necessary, surface finishing and film thickness adjustment by a method such as buffing, and the like.
Is formed thereon, and a solution in which one or more pyrene compounds and a binder are dissolved is applied thereon, dried and dried to form the charge transport layer 4.
May be formed. Here, the charge generation material used for forming the charge generation layer 5 is the same as that described in the description of the photosensitive layer 2 ′.

The thickness of the charge generation layer 5 is 5 μm or less, preferably 2 μm or less, and the thickness of the charge transport layer 4 is 3 to 50 μm.
μm, preferably 5 to 20 μm is suitable. In the type in which the charge generation layer 5 has the fine particles 3 of the charge generation layer material dispersed in a binder, the ratio of the fine particles 3 of the charge generation material to the charge generation layer 5 is preferably 10 to 95% by weight. Is about 50 to 90% by weight. The charge transport layer 4
Is 10 to 95% by weight, preferably 3% by weight.
0 to 90% by weight. To prepare the photoreceptor shown in FIG. 4, a solution in which a pyrene compound and a binder are dissolved is applied on the conductive support 1 and dried to form the charge transport layer 4, and then the charge transport layer 4 is formed. The charge generation layer 5 may be formed by applying and drying a dispersion of fine particles of the charge generation layer material in a solvent in which a binder is dissolved, if necessary, by a method such as spray coating. The amount ratio of the charge generation layer or the charge transport layer is the same as that described in FIG. The photoreceptor shown in FIG. 5 can be prepared by further forming a protective layer 6 on the thus-obtained photoreceptor charge generation layer 5 by a method such as spray coating. As the resin used here, a binder described later can be used.

In the production of any of these photoconductors, a metal plate or a metal foil such as aluminum, a plastic film on which a metal such as aluminum is vapor-deposited, or a paper subjected to a conductive treatment is used for the conductive support 1. Can be Examples of the binder include condensation resins such as polyamide, polyurethane, polyester, epoxy resin, polyketone, and polycarbonate; and vinyl polymers such as polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, and polyacrylamide. All insulating and adhesive resins can be used. If necessary, a plasticizer is added to the binder. Examples of such a plasticizer include halogenated paraffin, polychlorinated biphenyl, dimethylnaphthalene, and dibutylphthalate.

Further, the photosensitive member obtained as described above may be provided with an adhesive layer or a barrier layer between the conductive support and the photosensitive layer, if necessary. Materials used for these layers include polyamide, nitrocellulose,
Aluminum oxide and the like, and the film thickness is preferably 1 μm or less. To make a copy using the photoreceptor of the present invention,
After the photosensitive surface is charged and exposed, development is performed and, if necessary, transfer to paper or the like. The photoreceptor of the present invention has excellent advantages such as high sensitivity and high flexibility.

[0027]

The present invention will be described below with reference to examples. In the following examples, all parts are parts by weight.

[Compound specific example No. Synthesis Example 1) Tri-
2.02 g of n-butylphosphonio-9-fluorenide
(5.50 mmol) was dissolved in 10 ml of dry benzene, and 1.99 g (5.00 mmol) of N (1-pyrenyl) -N-phenyl-4-aminobenzaldehyde was dissolved under stirring.
And a solution of 20 ml of dry benzene were added dropwise at room temperature over 20 minutes. After further stirring at room temperature for 3.5 hours, the content was concentrated under reduced pressure to obtain a red-orange oil. This was treated with a silica gel column [eluent: toluene / c-hexane = (1/2) vol], and the pyrene compound was recrystallized with toluene to give orange-yellow plate-like compound No. 1 1 to 1.5
4 g (56.4% yield) was obtained. Melting point 259.5-26
0.5 ° C. Elemental analysis values were as follows: C ₄₂ H ₂₇ N C% H% N% Found 92.70 4.74 2.48 Calculated 92.44 4.99 2.51

Example 1 76 parts of Diane Blue (C.I. Pigment Blue 25, CI21180), 1260 parts of a 2% tetrahydrofuran solution of a polyester resin (Vylon 200, manufactured by Toyobo Co., Ltd.) and 3,700 parts of tetrahydrofuran were charged in a ball mill as charge generating substances. The resulting dispersion was applied using a doctor blade on the aluminum surface of a conductive base made of a polyester base on which aluminum was deposited, and was naturally dried to form a charge generation layer having a thickness of about 1 μm. . On the other hand, as the charge transport substance, Compound Specific Example No. 2 parts of a pyrene compound, 2 parts of a polycarbonate resin (Panlite K1300, manufactured by Teijin Limited) and 16 parts of tetrahydrofuran were mixed and dissolved to form a solution.
This was applied on the charge generation layer using a doctor blade and dried at 80 ° C. for 2 minutes and then at 120 ° C. for 5 minutes to form a charge transport layer having a thickness of about 20 μm.
o. 1 was created.

Examples 2 to 45 Except that the charge generating substance and the charge transporting substance (pyrene compound) were changed to those shown in Table 2, the photosensitive member Nos. 2-45 were made.

[Table 2- (1)]

[Table 2- (2)]

[Table 2- (3)]

[Table 2- (4)]

[Table 2- (5)]

[Table 2- (6)]

Example 46 Selenium was vacuum-deposited to a thickness of about 1 μm on an aluminum plate having a thickness of about 300 μm to form a charge generation layer. Next, No. 2 parts of a pyrene compound, 3 parts of a polyester resin (Polyester Adhesive 49000, manufactured by DuPont) and 45 parts of tetrahydrofuran were mixed and dissolved to prepare a charge transport layer forming solution, which was then charged into the above-mentioned charge generation layer (selenium deposition layer). ) Was applied thereon using a doctor blade, air-dried, and then dried under reduced pressure to form a charge transport layer having a thickness of about 10 μm. 46 was obtained.

Example 47 A perylene pigment is used instead of selenium

Embedded image To form a charge generation layer (thickness: about 0.6 μm), and a pyrene compound No. 1 as a charge transport material. 2 except that photoconductor N was used in exactly the same manner as in Example 46.
o. 47 were created.

Example 48 A mixture obtained by adding 158 parts of tetrahydrofuran to 1 part of Diane Blue (same as that used in Example 1) was ground and mixed in a ball mill. The photosensitive layer forming liquid obtained by adding 12 parts of the pyrene compound of No. 2 and 18 parts of a polyester resin (Polyester Adhesive 49000 manufactured by DuPont) and further mixing the mixture was applied on an aluminum-evaporated polyester film using a doctor blade. , 1
It was dried at 00 ° C. for 30 minutes to form a photosensitive layer having a thickness of about 16 μm. 48 were created.

Example 49 On a polyester film substrate on which aluminum was deposited,
The coating liquid for the charge transport layer used in Example 1 was coated with a blade in the same manner as in Example 1, and then dried to form a charge transport layer having a thickness of about 20 μm. Bisazo pigment (P-2) 13.
5 parts, polyvinyl butyral (trade name: XYHL Union Carbide Plastic Co., Ltd.) 5.4 parts, THF 6
After 80 parts and 1020 parts of ethyl cellosolve were pulverized and mixed in a ball mill, 1700 parts of ethyl cellosolve was added and mixed by stirring to obtain a coating liquid for a charge generation layer. This coating solution is spray-coated on the charge transport layer,
After drying for 0 minutes, a charge generation layer having a thickness of about 0.2 μm was formed. Further, a methanol / n-butanol solution of a polyamide resin (trade name: CM-8000, manufactured by Toray) is spray-coated on the charge generation layer, dried at 120 ° C. for 30 minutes, and dried to a thickness of about 0.5 μm. To form the photosensitive member N
o. 49 was created.

The photosensitive member No. 1-49
Using a commercially available electrostatic copying paper tester (type SP428, manufactured by KK Kawaguchi Electric Works), a corona discharge of -6 KV or +6 KV was performed for 20 seconds, and the surface was charged in a dark place for 20 seconds. The potential Vpo (volt) was measured, and then a tungsten lamp light was applied so that the illuminance on the photoreceptor surface became 4.5 lux, and the time (second) until the surface potential became 1/2 of Vpo was obtained. , Exposure amount E
1/2 (look-seconds) was calculated. Table 3 shows the results.

Further, after charging each of the above photoreceptors using a commercially available electrophotographic copying machine, the photosensitive members are irradiated with light through the original drawing to form an electrostatic latent image, and developed using a dry developer. When the obtained image (toner image) was electrostatically transferred onto plain paper and fixed, a clear transfer image was obtained. Similarly, when a wet type developer was used as the developer, a clear transfer image was obtained.

[Table 3- (1)]

[Table 3- (2)]

[Table 3- (3)]

[Table 3- (4)]

[0037]

The photoreceptor of the present invention is excellent in photosensitive characteristics, has high strength against heat and mechanical shock, and can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view enlarged in a thickness direction of an electrophotographic photosensitive member according to the present invention.

FIG. 2 is a cross-sectional view enlarged in a thickness direction of the electrophotographic photosensitive member according to the present invention.

FIG. 3 is a cross-sectional view enlarged in a thickness direction of the electrophotographic photosensitive member according to the present invention.

FIG. 4 is a cross-sectional view enlarged in a thickness direction of the electrophotographic photosensitive member according to the present invention.

FIG. 5 is a cross-sectional view enlarged in a thickness direction of the electrophotographic photosensitive member according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Conductive support 2, 2 ', 2 ", 2"', 2 "" ... Photosensitive layer 3 ... Charge generation material 4 ... Charge transport medium or charge transport layer 5 ... Charge generation layer 6 ... Protection layer

Continuation of front page (72) Inventor Chiaki Tanaka 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-4-323662 (JP, A) JP-A-2-190863 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 5/06 312 G03G 5/06 313 G03G 5/06 314 CA (STN)

Claims (1)

(57) [Claims] An electrophotographic photoreceptor comprising a conductive support and a photosensitive layer containing at least one pyrene compound represented by the following general formula (I) as an active ingredient: . Embedded image (In the above formula, R ¹ and R ² represent a halogen atom, a nitro group, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, or a substituted or unsubstituted phenyl group. R ³ represents a lower alkyl group or an alkoxy group, and l is 0 or 1 to
An integer of 5, m is 0 or an integer of 1 to 4, n is 0 or 1 to 3,
Represents an integer. When l, m or n is 2 or more, R
₁ , R ₂ and R ₃ may be the same or different.
X represents a substituted or unsubstituted carbocyclic group or a substituted or unsubstituted heterocyclic group)