JPH0519509A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance photosensitive characteristics and strength against heat shock and mechanical impact and to reduce cost by forming a photosensitive layer containing a specified dipyrenylamine derivative as an effective component on a conductive substrate. CONSTITUTION:The photosensitive layer 2 formed on the conductive substrate 1 contains as the effective component the dipyrenylamine derivative represented by formula I in which R is optionally substituted alkyl or such aryl. The photosensitive layer 2 comprising this derivative and a sensitizing dye and a binder resin is formed on the conductive substrate 1. The dipyrenylamine derivative acts as a photoconductive substance to generate and to transfer electric carriers necessary for photodecay, but since this derivative has almost no absorption in the visible light wavelength region, it is necessary to add a sensitizing dye having absorption in the visible wavelength region in the case of forming an image by the visible light.

Description

Detailed Description of the Invention

[0001]

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

[0002]

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

The basic characteristics required for a photoconductor in such an electrophotographic method are (1) being able to be charged to an appropriate potential in a dark place, (2) being less dissipated in a dark place, (3) It is possible to rapidly dissipate the electric charge by light irradiation.

By the way, in reality, each of the above-mentioned inorganic substances has many advantages and, at the same time, has various drawbacks. For example, selenium, which is widely used at present, sufficiently satisfies the above-mentioned conditions (1) to (3), but the manufacturing conditions are difficult, the manufacturing cost is high, the selenium is not flexible, and it is processed into a belt shape. It is difficult to handle, and it is sensitive to heat and mechanical shocks, so it requires careful handling. Cadmium sulfide and zinc oxide are used as photoconductors by dispersing them in a resin as a binder, but since they have mechanical defects such as smoothness, hardness, tensile strength and abrasion resistance, they can be repeated as they are. Can not be used.

In recent years, electrophotographic photoconductors using various organic substances have been proposed and some have been put to practical use in order to eliminate the drawbacks of these inorganic substances. For example, a photoreceptor comprising poly-N-vinylcarbazole and 2,4,7-trinitrofluoren-9-one (US Pat.
84237), a photoconductor obtained by sensitizing poly-N-vinylcarbazole with a pyrylium salt dye (described in JP-B-48-25658), and a photoconductor containing an organic pigment as a main component (special 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 a triphenylamine compound dye-sensitized. (US Pat. No. 3,180,730), a photoreceptor using an amine derivative as a charge transport material (JP-A-57-195254), poly-N-vinylcarbazole and an amine derivative as a charge transport material. Photoreceptor used (JP-A-58-11)
55), a photoconductor using a benzidine compound as a photoconductive material among polyfunctional tertiary amine compounds (US Pat. No. 3,265,496, JP-B-39-11546, JP-A-53-27033). ) And so on. These photoconductors have excellent properties and are considered to be of high value practically.However, in consideration of various demands on the photoconductor in the electrophotographic method, these requirements are still insufficient. The actual situation is that nothing satisfying the above conditions has been obtained.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the various drawbacks of the above-mentioned conventional photoconductors and to provide a photoconductor which can sufficiently satisfy the conditions required in electrophotography. Especially. Another object of the present invention is to provide an electrophotographic photosensitive member which is easy to manufacture, relatively inexpensive, and excellent in durability.

[0007]

According to the present invention, there is provided on a conductive support a photosensitive layer containing at least one dipyrenylamine derivative represented by the following general formula (I) (Formula I) as an active ingredient. An electrophotographic photoreceptor is provided which is characterized by the above.

[Chemical 1] (In the formula, R represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group.)

The dipyrenylamine derivative represented by the general formula (I) (Chemical formula 1) contained in the photosensitive layer in the present invention is, for example, the following general formula (II) (Chemical formula 2).

[Chemical 2] (Wherein, X represents a halogen atom such as bromine or iodine) and the general formula (III)
(Chemical formula 3)

Embedded image H ₂ N-R or (wherein, R is as defined above) is reacted with an amine derivative represented by), or the general formula (IV) (Formula 4)

[Chemical 4] And a di (1-pyrenyl) amine represented by the general formula (V)

Embedded image It is produced by reacting with a halide represented by X—R (wherein X and R are the same as above).

In the above general formulas (I), (II) and (V), R is a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, and when R is an aryl group, specific examples thereof include Is a phenyl group, a biphenyl group,
Examples thereof include non-condensed carbocyclic aromatic groups such as terphenyl groups and condensed polycyclic hydrocarbon groups or heterocyclic aromatic hydrocarbon groups.

In this case, the condensed polycyclic hydrocarbon group preferably has 18 or less carbon atoms forming a ring, for example, pentalenyl group, indenyl group, naphthyl group,
Azulenyl group, heptanenyl group, biphenylenyl group, a
s-indacenyl group, fluorenyl group, S-indacenyl group, acenaphthylenyl group, preadenyl group, acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrylenyl group, aceanthrylenyl group, triphenylenyl group Group, pyrenyl group, chrysenyl group, naphthacenyl group and the like.

Examples of the heterocyclic aromatic hydrocarbon group include the following groups. Thienyl group, furyl group, 2
-Pyridyl group, 4-pyridyl group, 3-indolyl group, 2
-Quinolinyl group, 3,4-benzpyranyl group, acridinyl group, thiazolyl group, benzothiazolonyl group, 9-methylcarbazolyl group, 9-ethylcarbazolyl group, 9-
Propylcarbazolyl group, 9-phenylcarbazolyl group, 9-tolylcarbazolyl group, 4-pyrazolyl group, etc.

The aryl group also includes those having the following substituents.

(1) Halogen atom, cyano group, nitro group (2) Alkyl group, preferably C _{2 to} C _12, especially C ₁
-C _8, more preferably a straight-chain or branched alkyl group of C ₁ -C _4, these alkyl groups may be further substituted hydroxyl group, a cyano group, an alkoxy group of C ₁ -C _4, a phenyl group or a halogen atom, C _{1 to} C ₄ alkyl group or C ₁ to
It may contain a phenyl group substituted with a C ₄ alkoxy group. Specifically, methyl group, ethyl group, n-propyl group, i-propyl group, t-butyl group, s-butyl group, n-butyl group, i-butyl group, 2-hydroxyethyl group, 2-cyanoethyl group. Group, 2-ethoxyethyl group, 2
-Methoxyethyl group, benzyl group, 4-chlorobenzyl group, 4-methylbenzyl group, 4-methoxybenzyl group,
4-phenylbenzyl group etc. are mentioned.

(3) Alkoxy group (--OR ₁ ); R ₁ represents the alkyl group defined in (2). Specifically, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, t-butoxy group, n-butoxy group, s-butoxy group, i-butoxy group, 2-hydroxyethoxy group, 2
-Cyanoethoxy group, benzyloxy group, 4-methylbenzyloxy group and the like can be mentioned.

(4) Aryloxy group: Examples of the aryl group include a phenyl group and a naphthyl group. This is C ₁
Alkoxy group -C _4, alkyl group, or a halogen atom C ₁ -C ₄ may contain a substituent group. Specifically, phenoxy group, 1-naphthyloxy group, 2-naphthyloxy group, 4-methylphenoxy group, 4-methoxyphenoquino group, 4-chlorophenoxy group, 6-methyl-2.
-A naphthyloxy group etc. are mentioned.

(5) Alkyl mercapto group (--S
R ₁ ); R ₁ represents an alkyl group defined in (2). Specific examples thereof include a methylthio group, an ethylthio group, a phenylthio group and a p-methylphenylthio group.

[0017] Alkyl group, or an aryl group, the aryl group such as phenyl group, and a biphenyl group or a naphthyl group, an alkoxy group, these C1 ■ -C ^4, C
Alkyl group of ¹ -C ^4, or a halogen atom may be contained as a substituent. R ² and R ³ may together form a ring. It may also form a ring in cooperation with the carbon atom on the aryl group. ) Specifically, an amino group, a diethylamino group,
Examples thereof include N-methyl-N-phenylamino group, N, N-diphenylamino group, N, N-di (p-tolyl) amino group, dibenzylamino group, piperidino group, morpholino group, and julolidyl group.

(7) An alkylenedioxy group such as a methylenedioxy group, a methylenedithio group or an alkylenedithio group, and the like.

In the general formulas (I), (III) and (V), when R is an alkyl group, specific examples thereof are the same as the specific examples of the (2) alkyl group described for the aryl group. .. Specific examples of R are the same as the specific examples of the substituent described for the aryl group.

Typical examples of the dipyrenylamine derivative represented by the general formula (I) are shown below.

[Table 1- (1)]

[Table 1- (2)]

[Table 1- (3)]

The photoreceptor of the present invention comprises one or more dipyrenylamine derivatives as described above in the photosensitive layer 2 (2 ',
2 ″, 2 ″ ″ or 2 ″ ″ ″), but as shown in FIG. 1, FIG. 2, FIG. 3, FIG. 4 or FIG. 5 depending on the application of these dipyrenylamine derivatives. Can be used for.

The photoreceptor shown in FIG. 1 comprises a conductive support 1 and a photosensitive layer 2 comprising a dipyrenylamine derivative, a sensitizing dye and a binder (binder resin). The dipyrenylamine derivative here acts as a photoconductive substance, and the generation and transfer of charge carriers necessary for light attenuation are performed via the dipyrenylamine derivative. However,
Since the dipyrenylamine derivative has almost no absorption in the visible region of light, it is necessary to add a sensitizing dye having absorption in the visible region for sensitization for the purpose of forming an image with visible light.

The photosensitive member shown in FIG. 2 is a photosensitive layer 2'wherein a charge generating substance 3 is dispersed on a conductive support 1 in a charge carrier medium 4 composed of a dipyrenylamine derivative and a binder.
Is provided. The dipyrenylamine derivative here forms a charge-carrying medium with the binder (or binder and plasticizer), while the charge-generating substance 3 (charge-generating substance such as an inorganic or organic pigment) generates charge carriers.
In this case, the charge carrier medium 4 is mainly responsible for receiving the charge carriers generated by the charge generating substance 3 and carrying them. The basic condition of this photoreceptor is that the charge-generating substance and the dipyrenylamine derivative do not overlap each other in the absorption wavelength region mainly in the visible region. This is because it is necessary to transmit light to the surface of the charge generating substance 3 in order to efficiently generate charge carriers in the charge generating substance 3. The dipyrenylamine derivative represented by the general formula (I) has almost no absorption in the visible region, generally absorbs light in the visible region, and when combined with the charge generating substance 3 which generates charge carriers, is particularly effective as a charge carrier substance. The feature is that it works.

The photosensitive member in FIG. 3 is a photosensitive layer 2 ″ composed of a laminate of a charge generating layer 5 having a charge generating substance 3 as a main component and a charge carrying layer 4 containing a dipyrenylamine derivative on a conductive support 1. Is provided. In this photoreceptor, the light transmitted through the charge transport layer 4 reaches the charge generation layer 5 and the charge carriers are generated in that region, while the charge transport layer 4 receives the charge carriers and carries them. However, the generation of charge carriers necessary for light attenuation depends on the charge generation material 3
And the transport of charge carriers is performed in the charge transport layer 4 (mainly the dipyrenylamine derivative works).
Such a mechanism is the same as that explained for the photoconductor shown in FIG.

The photoconductor in FIG. 4 has a third charge generation layer 5
The charge-transporting layer 4 containing the dipyrenylamine derivative and is laminated in the reverse order, and the mechanism for generating and transporting the charge carriers can be the same as described above. In this case, considering the mechanical strength, the protective layer 6 may be provided on the charge generation layer 5 as in the fifth case.

In order to actually produce the photoconductor of the present invention, the process shown in FIG.
In the case of the photoreceptor shown in 1 above, one or more dipyrenylamine derivatives are dissolved in a solution containing a binder, and a sensitizing dye is added to the solution to prepare a solution on the conductive support 1. Then, the photosensitive layer 2 may be formed by applying it to the substrate and drying.

The thickness of the photosensitive layer is 3 to 50 μm, preferably 5 to 20 μm. The amount of the dipyrenylamine derivative in the photosensitive layer 2 is 30 to 70% by weight, preferably about 50% by weight, and the amount of the sensitizing dye in the photosensitive layer 2 is 0.1 to 5% by weight, preferably 0.1. It is 5 to 3% by weight. As the sensitizing dye, triarylmethane dyes such as Brilliant Green, Victoria Blue B, Methyl Violet, Crystal Violet, Acid Violet 6B, Rhodamine B, Rhodamine 6G, Rhodamine G Extra, Eosin S, Erythrosine, Rose Bengal and Fluorescein can be used. Xanthene dye, such as
Thiazine dyes such as methylene blue, cyanine dyes such as cyanine, 2,6-diphenyl-4- (N, N-
Examples thereof include pyrylium dyes such as dimethylaminophenyl) thiapyrylium perchlorate and benzopyrylium salts (described in Japanese Patent Publication No. 48-25658). In addition, these sensitizing charges may be used alone or in combination of two or more kinds.

Further, in order to manufacture the photoconductor shown in FIG. 2, fine particles of the charge generating substance 3 are dispersed in a solution in which one or more dipyrenylamine derivatives and a binder are dissolved, and this is made conductive. The photosensitive layer 2 ′ may be formed by coating on the support 1 and drying.

The thickness of the photosensitive layer 2'is 3 to 50 μm, preferably 5 to 20 μm. The amount of the dipyrenylamine derivative in the photosensitive layer 2'is 10 to 95% by weight, preferably 30 to 90% by weight, and the amount of the charge generating substance 3 in the photosensitive layer 2'is 0.1 to 50% by weight. It is preferably 1 to 20% by weight. Examples of the charge generation substance 3 include inorganic pigments such as selenium, selenium-tellurium, cadmium sulfide, cadmium sulfide-selenium, and α-silicon, and examples of 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 (CI 45210), an azo pigment having a carbazole skeleton (described in JP-A-53-95033), an azo pigment having a distyrylbenzene skeleton ( JP-A-53-133445), an azo pigment having a triphenylamine skeleton (described in JP-A-53-132347), and an azo pigment having a dibenzothiophene skeleton (described in JP-A-54-21728). , Oxadia Azo pigments having Lumpur skeleton (JP 54-12742
JP-A No. 54-83834), azo pigments having a fluorenone skeleton (described in JP-A-54-22834), azo pigments having a bisstilbene skeleton (described in JP-A-54-17733), and distyryl oxadiazole. Azo pigments having a skeleton (described in JP-A No. 54-2129), azo pigments having a distyrylcarbazole skeleton (JP-A-5-2159)
JP-A-4-14967), for example, phthalocyanine-based pigments such as CI Pigment Blue 16 (CI74100), for example, CIVAT Brown 5 (CI 73410), CIVAT Die (CI).
73030) and the like, and perylene-based pigments such as Argos Scarlet B (manufactured by Bayer) and Indens Scarlet R (manufactured by Bayer). These charge-generating substances may be used alone or in combination of two or more.

Further, in order to manufacture the photoreceptor shown in FIG. 3, the charge generating substance is vacuum-deposited on the conductive support 1 or more, or the fine particles 3 of the charge generating substance are dissolved in a binder, if necessary. The charge generation layer 5 is formed by applying a dispersion liquid dispersed in a different solvent and drying it, and further, if necessary, performing surface finishing, film thickness adjustment, etc. by a method such as buffing.
Is formed, and a solution in which one or more kinds of dipyrenylamine derivatives and a binder are dissolved is applied thereon and dried to form the charge transport layer 4. The charge generating material used to form the charge generating layer 5 is the photosensitive layer 2 '.
Is the same as what was done in the explanation of.

The charge generation layer 5 has a thickness of 5 μm or less, preferably 2 μm or less, and the charge transport layer 4 has a thickness of 3 to 50.
μm, preferably 5 to 20 μm is suitable. When the charge generation layer 5 is of a type in which the fine particles 3 of the charge generation layer substance are dispersed in a binder, the proportion of the fine particles 3 of the charge generation substance in the charge generation layer 5 is preferably 10 to 95% by weight. Is about 50 to 90% by weight. In addition, the charge transport layer 4
The amount of the compound in 10 to 95% by weight, preferably 3
It is 0 to 90% by weight. In order to prepare the photoreceptor shown in FIG. 4, a solution in which a dipyrenylamine derivative and a binder are dissolved is applied on the conductive support 1 and dried to form the charge transport layer 4
After the formation of the charge-generating layer 5, fine particles of the charge-generating layer substance are dispersed on the charge-transporting layer, and a dispersion in which a binder is dissolved, if necessary, is applied and dried by a method such as spray coating. Should be formed. The amount ratio of the charge generation layer or the charge transport layer is the same as that described in FIG. The photoconductor shown in FIG. 5 can be prepared by further forming a protective layer 6 on the charge generation layer 5 of the photoconductor thus obtained by a method such as spray coating with a suitable resin solution. As the resin used here, the binder described below can be used.

In the production of any of these photoconductors, a metal plate or metal foil such as aluminum, a plastic film obtained by vapor-depositing a metal such as aluminum, or a paper subjected to a conductive treatment is used as the conductive support 1. Be done. As the binder, 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 are used. All insulating and adhesive resins can be used. If necessary, a plasticizer is added to the binder, and examples of such a plasticizer include halogenated paraffin, polychlorinated biphenyl, dimethylnaphthalene, dibutyl phthalate and the like.

Further, the photoreceptor 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 or the like is preferable, 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, it is developed and, if necessary, transferred to paper or the like. The photoconductor of the present invention has excellent advantages such as high sensitivity and high flexibility.

[0034]

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

[Synthesis of Compound of General Formula (I)] [Compound No. Synthesis Example of 19] p-toluidine 1.07
g (10.0 mmol), 1-iodopyrene 6.56 g
(20.0 mmol), potassium carbonate 5.53 g, copper powder 0.64 g and nitrobenzene 50 ml under a nitrogen stream.
While azeotropically dehydrating with an ester tube, the mixture was stirred at 207 ° C. for 6.5 hours. After allowing to cool to room temperature, it was filtered through Celite, and the filtrate was concentrated under reduced pressure to remove nitrobenzene. Chloroform was added to the obtained residue, the chloroform layer was washed with water, dried over magnesium sulfate, and concentrated under reduced pressure to give a dark brown oily substance. This was subjected to silica gel column treatment [eluent: toluene / n-hexane (1: 2) mixed solvent], and recrystallized from an ethanol / DMF mixed solvent,
1.33 g (yield 26.2%) of N, N-di (1-pyrenyl) -P-toluidine (compound No. 9) as yellow plate crystals.
Got The melting point was 272.5-273.5 ° C. The elemental analysis values were as follows as C ³⁹ H ²⁵ N.

Example 1 As a charge-generating substance, 76 parts of Diane Blue (CI Pigment Blue 25, CI21180), 1260 parts of a 2% tetrahydrofuran solution of polyester resin (Vylon 200, manufactured by Toyobo Co., Ltd.) and 3700 parts of tetrahydrofuran were placed in a ball mill. The resulting dispersion was pulverized and mixed with the above, and the resulting dispersion was applied on the aluminum surface of a conductive support made of aluminum vapor-deposited polyester using a doctor blade and naturally dried to form a charge generation layer having a thickness of about 1 μm. .. On the other hand, as the charge carrier substance, the compound specific example No. 2 parts of 9 dipyrenylamine derivative, polycarbonate resin (Panlite K1300, manufactured by Teijin Limited) 2
Parts and 16 parts of tetrahydrofuran were mixed and dissolved to form a solution, which was then applied on the charge generation layer using a doctor blade, and the mixture was heated at 80 ° C. for 2 minutes and then at 120 ° C. for 5 minutes.
After drying for a minute, a charge transport layer having a thickness of about 20 μm was formed, and the photoconductor No. Created 1.

Examples 2 to 33 Photoreceptor No. 3 was carried out in the same manner as in Example 1 except that the charge generating substance and the charge carrier substance (dipyrenylamine derivative) were replaced with those shown in Table 2. 2-33 were created.

[Table 2- (1)]

[Table 2- (2)]

[Table 2- (3)]

[Table 2- (4)]

[Table 2- (5)]

Example 34 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. Then No. 2 parts of 9 dipyrenylamine derivative, polyester resin (Polyester Adhesive 490 manufactured by DuPont)
00) 3 parts of tetrahydrofuran and 45 parts of tetrahydrofuran are mixed and dissolved to prepare a charge transport layer forming liquid, which is applied onto the above charge generating layer (selenium vapor deposition layer) using a doctor blade and naturally dried, and then decompressed. It is dried under and the thickness is about 10μ.
m charge carrier layer is formed, and the photoconductor No.
34 was obtained.

Example 35 Perylene pigment instead of selenium

[Chemical 6] To form a charge generation layer (thickness is about 0.6 μm), and the dipyrenylamine derivative No. In the same manner as in Example 34 except that the photoconductor No. 9 was used. 35 was created.

Example 36 A mixture of 1 part of Diane Blue (same as that used in Example 1) and 158 parts of tetrahydrofuran was pulverized and mixed in a ball mill, and then No. 12 parts of the dipyrenylamine derivative of 9 and 18 parts of a polyester resin (Polyester Adhesive 49000 manufactured by DuPont) were added, and the photosensitive layer forming liquid obtained by further mixing was applied onto an aluminum vapor-deposited polyester film using a doctor blade. , Dried at 100 ℃ for 30 minutes, thickness about 16μm
And the photosensitive layer of the present invention is formed. 36 was created.

Example 37 On a polyester film substrate vapor-deposited on aluminum,
The charge transport layer coating liquid used in Example 1 was blade coated 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 were added and mixed by stirring to obtain a charge generation layer coating liquid. This coating solution is spray-coated on the above charge transport layer, and the coating is carried out at 100 ° C. for 1 hour.
It was dried for 0 minutes to form a charge generation layer having a thickness of about 0.2 μm. 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 and dried at 120 ° C. for 30 minutes to form a protective layer having a thickness of about 0.5 μm. To form photoconductor N
o. 37 was created.

Photoreceptor No. 1 thus prepared 1-37
About the surface of the sheet at that time, after using a commercially available electrostatic copying paper tester (type SP428 manufactured by KK Kawaguchi Denki Seisakusho), the corona discharge of -6KV or + 6KV was performed for 20 seconds to charge it and then left in the dark for 20 seconds. The potential Vpo (volt) is measured, and then the tungsten lamp light is irradiated so that the illuminance on the surface of the photoconductor becomes 4.5 lux, and the time (second) until the surface potential becomes 1/2 of Vpo is obtained. , Exposure amount E
½ (lux · sec) was calculated. The results are shown in Table 3.

After charging each of the above photoconductors by using a commercially available electrophotographic copying machine, light irradiation is performed through an original drawing to form an electrostatic latent image, and the latent image is developed with a dry developer. When the obtained image (toner image) was electrostatically transferred and fixed on plain paper, a clear transferred image was obtained. Even when a wet type developer was used as the developer, a clear transfer image was similarly obtained.

[Table 3- (1)]

[Table 3- (2)]

[Table 3- (3)]

[Table 3- (4)]

[Effect] The photoconductor of the present invention is not only excellent in photosensitivity, but also has high strength against heat and mechanical shock, and can be manufactured at low cost.

[Brief description of drawings]

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

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

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

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Conductive support 2, 2 ', 2 ", 2"' ", 2" '' '... Photosensitive layer 3 ... Charge generating substance 4 ... Charge carrier medium or charge carrier layer 5 ... Charge generating layer 6 ... Protect layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Adachi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd.

Claims (1)

Claim: What is claimed is: 1. An electrophotographic photoreceptor comprising a conductive support and a photosensitive layer containing at least one dipyrenylamine derivative represented by the following general formula 1 as an active ingredient. .. [Chemical 1] (In the formula, R represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group.)