JPH05150491A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide the electrophotographic sensitive body high in sensitivity and superior in repetition characteristics and resistances to light and ozone. CONSTITUTION:The electrophotographic sensitive body is provided on a conductive substrate with a photosensitive layer containing an electric charge generating material, an electron transfer material represented by formula I, and a positive hole transfer material represented by formula II. In formulae I and II each of R1-R4 is, independently, H, alkyl, aryl, alkoxy, or benzyl; each of R5-R8 is, independently, H, lower alkyl, or alkoxy, each optionally and plurally substituted; and n is an integer of 0-3.

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 having an organic photosensitive layer provided on a conductive substrate, and more specifically, to an electronic device having high sensitivity and excellent repeatability, ozone resistance and light resistance. The present invention relates to a photoconductor.

[0002]

2. Description of the Related Art Recently, electrophotographic photoreceptors made of various materials have been proposed and used in image forming apparatuses such as copying machines utilizing the so-called Carlson process. One is an inorganic photoreceptor using an inorganic material such as selenium as a photosensitive layer, and the other is an organic photoreceptor using an organic material as a photosensitive layer. Organic photoconductors have many advantages such as being cheaper and higher in productivity than inorganic photoconductors and being non-polluting, and therefore extensive research has been conducted.

By the way, as a charge transport material, an electrophotographic photosensitive member is proposed, which uses a diphenoquinone compound as an electron transport material and a polysilane or a benzidine compound as a hole transport material, and which can be used in both positive and negative charging. Has been done.

[0004]

However, the above-mentioned electrophotographic photosensitive member has a drawback that the sensitivity is poor and the surface potential decreases when it is repeatedly used. Further ozone resistance,
The light resistance was insufficient.

The present invention is intended to solve the above-mentioned problems, and an object thereof is to provide an electrophotographic photosensitive member having high sensitivity and excellent repeating characteristics.

[0006]

The electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member in which an organic photosensitive layer containing a charge generating material, an electron transporting material and a hole transporting material is provided on a conductive substrate. In the body, the electron transport material is a compound represented by the following general formula (I), and the hole transport material is a compound represented by the following general formula (II). The above-mentioned subject can be achieved.

[0007]

[Chemical 3]

(In the formula, R ^{1 to} R ⁴ are, independently of each other,
Represents a hydrogen atom, an alkyl group, an aryl group, an alkoxy group or a benzyl group).

[0009]

[Chemical 4]

(In the formula, R ^{5 to} R ⁸ are each independently
Represents a hydrogen atom, a lower alkyl group or an alkoxy group,
Each of them may be substituted, and n represents an integer of 0 to 3).

Next, the present invention will be described in detail.

The electrophotographic photosensitive member of the present invention is constituted by providing an organic photosensitive layer containing a binder resin, a charge generating material and a charge transporting material on a conductive substrate. This organic photosensitive layer may be a single layer or may be formed of a plurality of layers (for example, a charge generation layer and a charge transport layer). When the organic photosensitive layer has a plurality of layers, the electron transport material represented by the general formula (I) and the hole transport material represented by the general formula (II) are preferably contained in the same layer. Further, a protective layer may be provided on the organic photosensitive layer, and an intermediate layer may be provided between the organic photosensitive layer and the conductive substrate.

As the charge generating material used in the present invention, conventionally known materials can be used. For example, A-type metal-free phthalocyanine, copper phthalocyanine, oxotitanyl phthalocyanine, 1,4-dithioketo-3,6- Diphenyl-pyrrolo- (3,4-c) pyrrolopyrrole,
2,7-bis (2-hydroxy-3- (2-chlorophenylcarbamoyl) -1-naphthylazo) fluorenone and the like can be mentioned.

The charge transport material used in the present invention is the electron transport material represented by the above general formula (I) and the hole transport material represented by the above general formula (II).

Further, in addition to the above charge transport material, the following charge transport material may be contained. For example, m-phenylenediamine compound; tetracyanoethylene; 2,4
Fluorenone compounds such as 7, -trinitro-9-fluorenone; Nitrated compounds such as dinitroanthracene;
Succinic anhydride; Maleic anhydride; Dibromomaleic anhydride; Triphenylmethane compounds; Oxadiazole compounds such as 2,5-di (4-dimethylaminophenyl) -1,3,4, -oxadiazole; Styryl compounds such as 9- (4-diethylaminostyryl) anthracene; carbazole compounds such as poly-N-vinylcarbazole; 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline and other pyrazoline compounds; 4,4 ',
4 ″,-tris (N, N-diphenylamino) triphenylamine and other amine derivatives; 1,1-bis (4-diethylaminophenyl) -4,4-diphenyl-1,3-
Conjugated unsaturated compounds such as butadiene; hydrazone compounds such as 4- (N, N-diethylamino) benzaldehyde-N, N-diphenylhydrazone; indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds Examples thereof include nitrogen-containing cyclic compounds such as compounds, imidazole compounds, pyrazole compounds, pyrazoline compounds, and triazole compounds; condensed polycyclic compounds and the like.

As the binder resin used in the present invention, any of those conventionally used in photoreceptor coating liquids can be used, and examples thereof include thermosetting silicone resins, epoxy resins, urethane resins, and curing resins. Acrylic resin, acrylic modified urethane resin, alkyd resin, unsaturated polyester resin, diallyl phthalate resin, phenol resin, urea resin, benzoguanamine resin, melamine resin, styrene polymer, acrylic polymer, styrene-acrylic polymer, Olefin polymers such as polyethylene, ethylene-vinyl acetate polymer, chlorinated polyethylene, polypropylene, and ionomer; polyvinyl chloride; vinyl chloride-vinyl acetate copolymer; polyvinyl acetate; saturated polyester; polyamide; thermoplastic urethane resin; polycarbonate ; Poly ants Over preparative; polysulfone; ketone resins, polyvinyl butyral resins; polyether resins. When the organic photosensitive layer is formed of a plurality of layers, the binder resin can be used to form each layer.

When the organic photosensitive layer is formed of a single layer,
The film thickness of the organic photosensitive layer is preferably 10 to 50 μm, more preferably 15 to 30 μm.

When the organic photosensitive layer is formed of a single layer,
The content of the charge generating material is the same as that of the binder resin 1 of the organic photosensitive layer.
The content is preferably 0.5 to 15 parts by weight, more preferably 1 to 10 parts by weight, based on 00 parts by weight. When the content of the charge generation material is less than 0.5 part by weight, the sensitivity of the obtained photoreceptor is lowered. On the other hand, if the content of the charge generation material exceeds 15 parts by weight, the abrasion resistance of the obtained photoreceptor may be reduced.

The content of the electron transport material represented by the general formula (I) is preferably in the range of 5 to 100 parts by weight with respect to 100 parts by weight of the binder resin of the organic photosensitive layer,
More preferably, it is 20 to 50 parts by weight. When the content of the above electron transport material is less than 5 parts by weight, the repeating characteristics of the obtained photoreceptor are deteriorated. On the contrary, when the content of the electron transport material exceeds 100 parts by weight, the abrasion resistance of the obtained photoreceptor may be deteriorated. Further, it is preferably contained in an amount of 50 to 100 parts by weight based on 100 parts of the charge generation material.

The content of the hole transport material represented by the general formula (II) is preferably 10 to 200 parts by weight based on 100 parts by weight of the binder resin of the organic photosensitive layer, More preferably, it is 50 to 200 parts by weight. When the content of the hole transport material is less than 10 parts by weight, the sensitivity of the resulting photoreceptor becomes poor. On the other hand, when the content of the hole transport material exceeds 200 parts by weight, the abrasion resistance of the obtained photoreceptor may be reduced. Further, it is preferably contained in an amount of 5 to 50 parts by weight based on 100 parts by weight of the charge generation material.

The content of the electron transporting material represented by the general formula (I) is 20 to 70% by weight in the charge transporting material.
It is contained, particularly preferably 20 to 50% by weight. If the content of the electron transporting material in the charge transporting material is less than 20% by weight, the repetitive characteristics of the resulting photoreceptor will be poor. On the other hand, when the content of the electron transport material exceeds 70% by weight, the sensitivity of the obtained photoreceptor becomes poor.

The content of the hole transport material represented by the general formula (II) is 20 to 70% by weight, and particularly 20 to 50% by weight in the charge transport material. preferable. When the content of the hole transporting material in the charge transporting material is less than 20% by weight, the repetitive characteristics of the obtained photoreceptor are deteriorated. On the contrary, when the content of the hole transport material exceeds 70% by weight, the sensitivity of the obtained photoreceptor becomes poor.

When the organic photosensitive layer is composed of a charge generation layer and a charge transport layer, the thickness of the charge generation layer is 0.01 to.
It is preferably 3 μm, more preferably 0.1 to 2 μm. The thickness of the charge transport layer is preferably 2 to 100 μm,
More preferably, it is 5 to 30 μm.

The content of the charge generating material is preferably 20 to 300 parts by weight, more preferably 50 parts by weight, based on 100 parts by weight of the binder resin of the organic photosensitive layer.
~ 200 parts by weight. When the content of the charge generating material is less than 20 parts by weight, the resulting photoreceptor has a low charge generating concentration. On the contrary, when the content of the charge generating material exceeds 300 parts by weight, the mechanical strength of the obtained photoreceptor is low. It may decrease.

The content of the electron transporting material represented by the general formula (I) is preferably in the range of 5 to 100 parts by weight with respect to 100 parts by weight of the binder resin of the organic photosensitive layer,
More preferably, it is 20 to 50 parts by weight. When the content of the above electron transport material is less than 5 parts by weight, the repeating characteristics of the obtained photoreceptor are deteriorated. On the contrary, when the content of the electron transport material exceeds 100 parts by weight, the abrasion resistance of the obtained photoreceptor may be deteriorated. Further, it is preferably contained in an amount of 50 to 100 parts by weight based on 100 parts of the charge generation material.

The content of the hole transport material represented by the general formula (II) is preferably 10 to 200 parts by weight based on 100 parts by weight of the binder resin of the organic photosensitive layer, More preferably, it is 50 to 200 parts by weight. When the content of the hole transport material is less than 10 parts by weight, the sensitivity of the resulting photoreceptor becomes poor. On the other hand, when the content of the hole transport material exceeds 200 parts by weight, the abrasion resistance of the obtained photoreceptor may be reduced. Further, it is preferably contained in an amount of 5 to 50 parts by weight based on 100 parts by weight of the charge generation material.

The content of the electron transport material represented by the general formula (I) is 20 to 70% by weight in the charge transport material.
It is contained, particularly preferably 20 to 50% by weight. If the content of the electron transporting material in the charge transporting material is less than 20% by weight, the repetitive characteristics of the resulting photoreceptor will be poor. On the other hand, when the content of the electron transport material exceeds 70% by weight, the sensitivity of the obtained photoreceptor becomes poor.

The content of the hole transport material represented by the above general formula (II) is 20 to 70% by weight, and particularly 20 to 50% by weight in the charge transport material. preferable. When the content of the hole transporting material in the charge transporting material is less than 20% by weight, the repetitive characteristics of the obtained photoreceptor are deteriorated. On the contrary, when the content of the hole transport material exceeds 70% by weight, the sensitivity of the obtained photoreceptor becomes poor.

Further, the organic photosensitive layer may contain various additives such as an antioxidant and a quencher.

The conductive substrate used in the present invention is formed in a suitable shape such as a sheet shape or a drum shape according to the mechanism and structure of the image forming apparatus in which the electrophotographic photosensitive member is incorporated. The conductive substrate may be entirely formed of a conductive material such as metal, or the base material may be formed of a material having no conductivity and the surface thereof may be provided with a material having conductivity. Good. As the conductive material, for example, the surface is alumite-treated, or untreated aluminum,
Examples include copper, tin, platinum, gold, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, brass, etc. Especially, anodic oxidation by sulfuric acid alumite method and sealing with nickel acetate. Treated aluminum is preferably used. In the case of a conductive substrate formed by providing a conductive material on the surface of a base material made of a material having no conductivity, on the surface of a synthetic resin base material or a glass base material, the above-mentioned metal or A thin film made of a conductive material such as aluminum iodide, tin oxide, or indium oxide formed by a known film forming method such as a vacuum deposition method or a wet plating method, or a film of the metal material or the like on the surface of the base material. It is possible to employ, for example, a laminate of the above, a substrate in which a substance that imparts conductivity is injected into the surface of the base material, or the like. The conductive base material may be subjected to a surface treatment with a surface treatment agent such as a silane coupling agent or a titanium coupling agent, if necessary, to enhance the adhesiveness with the organic photosensitive layer.

In the electrophotographic photoreceptor of the present invention, when the organic photosensitive layer is a single layer, at least a binder resin, a charge generating material,
A coating solution prepared by dispersing the electron transport material represented by the general formula (I) and the hole transport material represented by the general formula (II) in dichloromethane or the like as a solvent or a dispersion medium,
It can be prepared by coating on a conductive substrate by a usual coating method such as a spray coating method, a dipping method or a flow coating method to form an organic photosensitive layer. When the organic photosensitive layer has a plurality of layers, at least a binder resin and the above-mentioned binder resin are formed after forming a charge generating layer by applying a coating liquid in which at least a binder resin and a charge generating material are dispersed in a solvent onto a conductive substrate. An electrophotographic photosensitive material is obtained by further applying a coating liquid in which an electron transporting material represented by the general formula (I) and a hole transporting material represented by the general formula (II) are dispersed in a solvent to form a charge transporting layer. Can form a body. Alternatively, the charge-transporting layer may be formed first, and then the charge-generating cleaning may be formed.

It is preferable to perform heat treatment in order to reduce the residual amount of dichloromethane contained in the organic photosensitive layer. For example, the conductive substrate coated with the above coating solution is heat treated at a temperature of 50 ° C. or more for 60 minutes or more. Preferably. When the heat treatment temperature is lower than the above conditions, the residual amount of dichloromethane may not be sufficiently reduced.

As the solvent or dispersion medium used in the coating solution, other solvent or dispersion medium can be used alone or in combination with dichloromethane in addition to dichloromethane.

Examples of such a solvent or dispersion medium include the following. Aliphatic hydrocarbons such as n-hexane, octane and cyclohexane; aromatic hydrocarbons such as benzene, xylene and toluene; halogenated hydrocarbons such as carbon tetrachloride and chlorobenzene; methyl alcohol, ethyl alcohol, isopropyl alcohol, allyl alcohol, Alcohols such as cyclopentanol, benzyl alcohol, furfuryl alcohol, diacetone alcohol; dimethyl ether, diethyl ether,
Ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether and tetrahydrofuran; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; esters such as ethyl acetate and methyl acetate; dimethylformamide; dimethyl sulfoxide and the like.

The coating solution is prepared by a conventionally known method, for example, mixer, ball mill, paint shaker, sand mill,
It can be prepared using an attritor, an ultrasonic disperser or the like. When preparing the above coating liquid, a surfactant, a leveling agent or the like may be added in order to improve dispersibility, coatability and the like.

[0036]

EXAMPLES The present invention will be described below with reference to examples and comparative examples.

Examples 1-9 and Comparative Examples 1-3 5 parts by weight of metal-free phthalocyanine as a charge generating material, 40 parts by weight of the compound shown in Table 1 as a hole transfer agent,
The diphenoquinone compound 40 shown in Table 1 as an electron transfer agent
By weight, 100 parts by weight of a polycarbonate resin as a binder resin and 800 parts by weight of dichloromethane as a solvent were mixed and dispersed in a paint shaker to prepare a coating liquid for a single-layer type photosensitive layer. The prepared solution was applied on an aluminum foil with a wire bar and then dried by heating at 60 ° C. for 120 minutes to obtain an electrophotographic photosensitive member having a single-layer type photosensitive layer having a film thickness of 15 to 20 μm.

The charging characteristics and photosensitive characteristics of the electrophotographic photosensitive members obtained in Examples 1 to 9 and Comparative Examples 1 to 3 were evaluated according to the following methods, and the results are shown in Table 1.

1) Measurement of initial surface potential V1sp A single layer type electrophotographic photosensitive member was applied with an applied voltage to the obtained photosensitive member by using an electrostatic copying tester (EPA-8100 manufactured by Kawaguchi Denki KK). The surface potential was charged positively or negatively, and the surface potential V1 (V) was measured.

2) Measurement of half-exposure amount E1 / 2 and residual potential V2 The surface potential V1 of the photosensitive member in the above charged state was 1/2 by using a halogen lamp as an exposure light source of an electrostatic copying tester.
Until the half-exposure amount E1 / 2 (lux.
sec) was calculated. Further, the surface potential after 5 seconds from the exposure was measured and defined as the residual potential V2 (V).

3) Measurement of repetitive characteristics ΔV1 and ΔV2 The obtained photoconductor was mounted on a copying machine, the surface potential V1 and the residual potential V2 after 1000 cycles of copying were measured, and V1 and V2 were measured. Was calculated as the surface potential change ΔV1 and the residual potential change ΔV2.

4) Evaluation of Light Resistance The surface of the obtained photoreceptor is adjusted with a white fluorescent lamp so that the light amount is 1000 lux, and irradiation is carried out for 60 minutes.
Difference between surface potential and residual potential before and after that ΔV1 and Δ
V2 was measured.

Examples 10 to 15 and Comparative Examples 4 to 7 Metal-free phthalocyanine 10 was used as the charge generating material.
0 parts by weight, polyvinyl butyral resin 1 as a binder resin
Parts by weight and 120 parts by weight of tetrahydrofuran were dispersed by a ball mill. This dispersion was applied onto an aluminum foil with a wire bar and then dried by heating at 100 ° C. for 1 hour to form a charge generation layer having a film thickness of 0.5 μm.

On this charge generating layer, 40 parts by weight of the compound shown in Table 1 as a hole transfer agent, 40 parts by weight of the diphenoquinone compound shown in Table 1 as an electron transfer agent, and 100 parts by weight of a polycarbonate resin as a binder resin were added to 80 dichloromethane.
After coating the solution dissolved in 0 parts by weight with a wire bar, it is dried by heating at 90 ° C. for 1 hour to give a film thickness of 15
A μm charge transport layer was formed to obtain a laminated electrophotographic photoreceptor.

Examples 10 to 15 and Comparative Examples 4 to 7
The charging characteristics and the photosensitive characteristics of the electrophotographic photosensitive member obtained in 1. were evaluated according to the following methods, and the results are shown in Table 2.

1) Measurement of initial surface potential V1sp A single layer type electrophotographic photosensitive member was applied with an applied voltage to the obtained photosensitive member by using an electrostatic copying tester (EPA-8100 manufactured by Kawaguchi Denki KK). The surface potential was charged positively or negatively, and the surface potential V1 (V) was measured.

2) Measurement of half-dose exposure amount E1 / 2 and residual potential V2 The surface potential V1 of the photoconductor in the charged state was reduced to 1/2 by using a halogen lamp as an exposure light source of an electrostatic copying tester.
Until the half-exposure amount E1 / 2 (lux.
sec) was calculated. Further, the surface potential after 5 seconds from the exposure was measured and defined as the residual potential V2 (V).

3) Evaluation of light resistance The amount of light was adjusted to 1000 lux on the surface of the obtained photoreceptor by using a white fluorescent lamp, and irradiation was performed for 60 minutes.
Difference between surface potential and residual potential before and after that ΔV1 and Δ
V2 was measured.

4) Evaluation of ozone resistance Corona discharge was performed to fill ozone (20 ppm).
The obtained photoreceptor was left in the box for 2 hours. The difference ΔV1 and ΔV2 between the surface potential and the residual potential before and after that were measured.

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

[Chemical 5]

[0053]

[Chemical 6]

[0054]

[Chemical 7]

From Tables 1 and 2, it can be seen that the electrophotographic photosensitive members of the examples have excellent repeating characteristics.

[0056]

As is apparent from the above description, according to the present invention, it is possible to provide an electrophotographic photoreceptor having high sensitivity and excellent repetitive characteristics, light resistance and ozone resistance.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuyuki Hanatani 1-2-2 Tamazo, Chuo-ku, Osaka Mita Engineering Co., Ltd.

Claims (1)

[Claims] 1. An electrophotographic photoreceptor having an organic photosensitive layer containing a charge generating material, an electron transporting material and a hole transporting material provided on a conductive substrate, wherein the electron transporting material has the following general formula (I): ), And the hole transport material is a compound represented by the following general formula (II). [Chemical 1] (In the formula, R ^{1 to} R ⁴ each independently represent a hydrogen atom, an alkyl group, an aryl group, an alkoxy group or a benzyl group.) (In the formula, R ^{5 to} R ⁸ each independently represent a hydrogen atom, a lower alkyl group or an alkoxy group, and each may be substituted with a plurality of groups, and n represents an integer of 0 to 3.)