JP2000305298A - Electrophotographic photoreceptor and electrophotographic method using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor excellent in film forming property and wear resistance without impairing sensitivity characteristics of an organic photoreceptor though an electric charge transferring layer in a function separation type laminated photoreceptor is formed using a low molecular transferring material and a resin binder and to provide an electrophotographic method in which the photoreceptor is excellent in repetitive characteristics. SOLUTION: An electric charge generating layer based on an intrinsic electric charge generating material and an electric charge transferring layer containing 25-35 wt.% triarylamine or its derivative as an electric charge transferring material are laminated on an electrically conductive substrate to obtain the objective electrophotographic photoreceptor. The thickness of the electric charge transferring layer is <=15 μm.

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 an electrophotographic method using the same, and more particularly, to an electrophotographic photoreceptor excellent in abrasion resistance without deteriorating light attenuation characteristics, and excellent in the photoreceptor. The present invention relates to an electrophotographic method used in various environments.

[0002]

2. Description of the Related Art As an electrophotographic method, a Carlson process and various other deformation processes are known.
Widely used in copiers and printers. Among the photoreceptors used in such an electrophotographic method, those using an organic photosensitive material have recently begun to be used because of their advantages of low cost, mass productivity, and no pollution. Organic electrophotographic photoreceptors include polyvinyl carbazole (P
VK), a photoconductive resin represented by PVK-TNF
(2,4,7-trinitrofluorenone), a charge transfer complex type represented by (2,4,7-trinitrofluorenone), a pigment dispersion type represented by phthalocyanine-binder, a function-separated type photoconductor using a combination of a charge generating substance and a charge transporting substance, etc. And, in particular, a function-separated type photoreceptor has attracted attention and has been put to practical use.

[0003] It is known that in a function-separated type photoreceptor, a charge transport material having absorption mainly in the ultraviolet region and a charge generation material having absorption mainly in the visible to near infrared region are used in combination. Useful. Many charge transport materials have been developed as low molecular weight compounds. However, since low molecular weight compounds alone do not have a film-forming property, they are usually used by being dispersed and mixed in an inert polymer. Such a functional film is called a molecular dispersed polymer.

However, the charge transport layer composed of a low molecular charge transport material and an inert polymer is generally soft, and the Carlson process is liable to cause film shaving due to repeated use. Furthermore, the charge transport layer having this configuration has a limit in charge mobility, and has recently been an obstacle to speeding up or downsizing of the Carlson process, which is strongly oriented. That is, although the electrophotographic photosensitive member described in the Journal of the Electrophotographic Society of Japan, vol. 25, pp. 83-89, certainly exhibits a faster photoresponse characteristic than the conventional one, it is satisfied from the above-mentioned orientation of the Carlson process. However, further improvement in this respect has been strongly desired.

[0005] Recently, with the trend toward higher speed or smaller size of the Carlson process, organic photoconductors are also expected to have higher sensitivity. Under such circumstances, the charge transport layer composed of a molecular dispersion polymer, when used in combination with a certain kind of charge generating material, the sensitivity is significantly dependent on the charge transport material content in the charge transport layer, For example, it is described in Journal of Applied Physics, Vol. 72, p. 117, and Journal of Imaging Science and Technology, Vol. 38, p. 281. According to the viewpoint based on such sensitivity, the higher the charge transport material concentration in the charge transport layer, the better, but from the viewpoint of film forming properties and abrasion resistance, the lower the charge transport material concentration, the better. He had a conflict. As described above, the charge transporting layer usually has a charge transporting material of 6 to
It is known that it is used in an amount of 10 parts by weight. In practical use, the charge transport material is used in an amount of 7 parts per 10 parts by weight of the binder resin.
It is often used at up to 9 parts by weight.

[0006]

SUMMARY OF THE INVENTION A first object of the present invention is to provide a functionally separated type photoreceptor, in which a charge transport layer is formed of a low molecular transport material and a binder resin, despite the conventional organic photoreceptor. Without impairing the sensitivity characteristics of the photoreceptor
An object of the present invention is to provide an electrophotographic photosensitive member having excellent film forming properties and abrasion resistance. Another object of the present invention is to provide an electrophotographic method which is excellent in the repetition characteristics of the photoreceptor.

[0007]

Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above object, and as a result, while forming the charge transport layer from a conventionally known low molecular charge transport material and a binder polymer, The present inventors have found that a multilayer photoreceptor comprising a combination of a specific charge generating material and a charge transporting layer with a reduced content of a charge transporting material can stably cope with an electrophotographic process, and completed the present invention. Was.

That is, according to the present invention, first, a charge generation layer containing an intrinsic charge generation material as a main component and a charge transport layer containing a triarylamine or a derivative thereof as a charge transport material on a conductive substrate. Wherein the charge transport material in the charge transport layer has a content of 2
An electrophotographic photoreceptor characterized in that the charge transport layer has a thickness of 5 to 35% by weight and a thickness of 15 μm or less.

Secondly, there is provided the electrophotographic photosensitive member as described in the first aspect, wherein the charge transporting material is a compound selected from the following formulas (1) and / or (2). .

Embedded image (Wherein, R ₁ and R ₂ represent a hydrogen atom, a substituted or unsubstituted lower alkyl group, or a substituted or unsubstituted aryl group, and R ₃ , R ₄ and Ar ₁ represent a substituted or unsubstituted aryl group. And Ar ₂ represents a substituted or unsubstituted arylene group, Ar ₁ and R ₁ may form a ring together, and n is an integer of 0 or 1.)

Embedded image (Wherein R ₁ , R ₃ and R ₄ are a hydrogen atom, an amino group, an alkoxy group, a thioalkoxy group, an aryloxy group, a methylenedioxy group, a substituted or unsubstituted alkyl group, a halogen atom, or a substituted or unsubstituted Is an aryl group of R
₂ represents a hydrogen atom, an alkoxy group, a substituted or unsubstituted alkyl group or a halogen atom, respectively. Also, k,
l, m and n are integers of 1, 2, 3 or 4, and when each is an integer of 2, 3 or 4, R ₁ , R ₂ , R ₃ and R ₄ may be the same or different Good. )

Thirdly, there is provided the electrophotographic photosensitive member according to the first or second aspect, wherein phthalocyanine is used as the charge generating material.

Fourth, the electrophotographic photoreceptor according to the first, second or third aspect is provided with at least charging, image exposure, development,
In an electrophotographic method in which transfer, cleaning, and static elimination are repeatedly performed, the maximum electric field intensity applied to the photosensitive layer is 3000.
An electrophotographic method characterized by being at most 00 V / cm.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. First, the configuration of the electrophotographic photosensitive member of the present invention will be described with reference to the drawings. FIGS. 1 and 2 are basic layer configuration diagrams showing the electrophotographic photoreceptor of the present invention, which has a configuration in which a charge generation layer 35 and a charge transport layer 37 are laminated on a conductive substrate 31.

The conductive support 31 has a volume resistance of 10
Those exhibiting conductivity of ¹⁰ Ωcm or less, for example, aluminum, nickel, chromium, nichrome, copper, gold, silver, metals such as platinum, tin oxide, metal oxides such as indium oxide, by evaporation or sputtering, Plates made of film or cylindrical plastic or paper, or plates made of aluminum, aluminum alloy, nickel, stainless steel, etc. and extruded and drawn into a tube, then cut, super-finished, polished, etc. Surface-treated tubes and the like can be used. Also, Japanese Patent Application Laid-Open
Endless nickel belt and endless stainless belt disclosed in JP-A-36016 are also conductive supports 31.
Can be used as

In addition to the above, a support obtained by dispersing a conductive powder on a suitable binder resin on the above support and applying the same can also be used as the conductive support 31 of the present invention. As the conductive powder, carbon black, acetylene black, aluminum, nickel, iron, nichrome, copper, zinc,
Metal powder such as silver, or metal oxide powder such as conductive tin oxide and ITO may be used. Further, the binder resin used simultaneously, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer,
Styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral , Polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenolic resin, phenolic resin, alkyd resin, etc., thermoplastic resin, thermosetting resin or photocurable resin. No. Such a conductive layer can be provided by dispersing the conductive powder and the binder resin in an appropriate solvent, for example, tetrahydrofuran, dichloromethane, methyl ethyl ketone, toluene, or the like, and applying the dispersion.

Further, a conductive material is formed on a suitable cylindrical substrate by means of a heat-shrinkable tube made of a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, or Teflon containing the above-mentioned conductive powder. Those provided with a layer can also be favorably used as the conductive support 31 of the present invention.

The charge generation layer 35 is a layer containing an intrinsic type charge generation material as a main component, and may use a binder resin as needed. The intrinsic charge generation material referred to here is a material having sufficient photoelectric conversion ability by itself,
The so-called sensitizer significantly increases the photoelectric conversion capacity.
It is distinguished from extrinsic charge generating materials.

As the intrinsic charge generation material, an inorganic material and an organic material can be used. Inorganic materials include
Crystalline selenium, amorphous selenium, selenium-tellurium,
Examples include selenium-tellurium-halogen, selenium-arsenic compounds, and amorphous silicon. amorphous·
In silicon, dangling bonds are replaced by hydrogen atoms,
Terminating with a halogen atom, boron atom,
Those doped with phosphorus atoms or the like are preferably used. On the other hand, examples of the organic material include a phthalocyanine-based pigment and a naphthalocyanine-based pigment. Among these endogenous charge generating substances, phthalocyanine pigments exhibit high sensitivity to near-infrared to red light and are preferably used in an imaging system using a digital light source. These charge generating substances may be used alone or in combination of two or more.

The binder resin optionally used for the charge generation layer 35 includes polyamide, polyurethane,
Epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene,
Poly-N-vinyl carbazole, polyacrylamide and the like can be mentioned. These binder resins can be used alone or as a mixture of two or more. The binder resin is used in an amount of 0 to 100 based on 100 parts by weight of the charge generating substance.
It is suitable to use parts by weight, preferably 0 to 50 parts by weight.

The method for forming the charge generating layer 35 includes a vacuum thin film forming method and a casting method from a solution dispersion system. As the former method, a vacuum evaporation method, a glow discharge decomposition method, an ion plating method, a sputtering method, a reactive sputtering method, a CVD method, or the like is used, and the above-mentioned inorganic material and organic material can be favorably formed.

In order to form the charge generation layer by the latter casting method, the above-mentioned inorganic or organic charge generation material is used together with a binder resin, if necessary, using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane or butanone. It can be formed by dispersing with a ball mill, an attritor, a sand mill, or the like, diluting the dispersion liquid appropriately, and applying. The coating can be performed by a dip coating method, a spray coating method, a bead coating method, or the like. The thickness of the charge generation layer provided as described above is appropriately about 0.01 to 5 μm, and preferably 0.05 to 2 μm.

The charge transport layer 37 is composed of a charge transport material and a binder resin, and can be provided by dispersing or melting the charge transport material and the binder resin in an appropriate solvent, and coating and drying. As the charge transporting material of the present invention, triarylamine or a derivative thereof is used. In particular, materials represented by the following general formulas (1) to (17) are preferably used. Hereinafter, examples of typical triarylamine compounds are shown by a general formula.

(1) Compound represented by the following general formula (1)

Embedded image (Wherein, R ₁ and R ₂ represent a hydrogen atom, a substituted or unsubstituted lower alkyl group, or a substituted or unsubstituted aryl group, and R ₃ , R ₄ and Ar ₁ represent a substituted or unsubstituted aryl group. And Ar ₂ represents a substituted or unsubstituted arylene group, Ar ₁ and R ₁ may form a ring together, and n is an integer of 0 or 1.)

(2) Compound represented by the following general formula (2)

Embedded image (Wherein R ₁ , R ₃ and R ₄ are a hydrogen atom, an amino group, an alkoxy group, a thioalkoxy group, an aryloxy group, a methylenedioxy group, a substituted or unsubstituted alkyl group, a halogen atom, or a substituted or unsubstituted Is an aryl group of R
₂ represents a hydrogen atom, an alkoxy group, a substituted or unsubstituted alkyl group or a halogen atom, respectively. Also, k,
l, m and n are integers of 1, 2, 3 or 4, and when each is an integer of 2, 3 or 4, R ₁ , R ₂ , R ₃ and R ₄ may be the same or different Good. )

(3) Compound represented by the following general formula (3)

Embedded image (Wherein, R ₁ represents a lower alkyl group, a lower alkoxy group or a halogen atom, n represents an integer of 0 to 4, R ₂ and R ₃ may be the same or different, and represent a hydrogen atom, a lower alkyl group , A lower alkoxy group or a halogen atom.)

(4) Compound represented by the following general formula (4)

Embedded image (In the formula, R ₁ , R ₂ and R ₃ may be the same or different and represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a phenyl group, a phenoxy group or a halogen atom.)

(5) Compound represented by the following general formula (5)

Embedded image (Wherein R ₁ and R ₂ are a hydrogen atom, an amino group, a substituted or unsubstituted dialkylamino group, an alkoxy group, a thioalkoxy group, an aryloxy group, a substituted or unsubstituted alkyl group, a halogen atom, or a substituted or unsubstituted R ₃ and R _{4 each} represent a hydrogen atom, an alkoxy group, a substituted or unsubstituted alkyl group or a halogen atom, and Ar represents a substituted or unsubstituted monocyclic aromatic hydrocarbon group, Or an unsubstituted uncondensed polycyclic aromatic hydrocarbon group or a substituted or unsubstituted heterocyclic group.)

(6) Compound represented by the following general formula (6)

Embedded image (In the formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, which may be the same or different.)

(7) Compound represented by the following general formula (7)

Embedded image (In the formula, R ₁ and R ₂ represent a substituted or unsubstituted aryl group.)

(8) Compound represented by the following general formula (8)

Embedded image (Wherein, R ₁ and R ₂ represent a substituted or unsubstituted aryl group, and R ₁ and R ₂ may be the same or different.
₃ and R ₄ represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, and m is an integer of 1, 2 or 3,
n is an integer of 1, 2, 3 or 4, and when m and n are respectively plural, R ₃ and R ₄ may be the same or different. )

(9) Compound represented by the following general formula (9)

Embedded image(Wherein, m is an integer of 0 or 1, and when m = 1, X
Is an oxygen atom, a sulfur atom,> NR, -CH_Two-, -CH_Two
-CH_Two— Or —CH ＝ CH—, and R₁And R _TwoIs
Represents a substituted or unsubstituted aryl group. Also, R_Threeas well as
R_FourIs a hydrogen atom, an alkyl group, an alkoxy group or a halogen
Represents an atom. Ar represents a carbocyclic aromatic group or a heterocyclic group
Represent. n is an integer of 0 or 1. R_ThreeIs working with X
You may form a benzene ring. )

(10) Compound represented by the following general formula (10)

Embedded image (In the formula, Ar represents a substituted or unsubstituted biphenylene group, and R ₁ , R ₂ and R ₃ represent a hydrogen atom, a halogen atom,
A cyano group, or an alkyl group which may have a substituent, an alkoxy group, an aryloxy group, an alkyl mercapto group,
Represents a methylenedioxy group, a methylenedithio group, or an aryl group, and R ₁ , R ₂ and R ₃ may be the same or different. Also, l, m and n represent an integer of 1 to 5,
When each is an integer of 2 to 5, R ₁ , R ₂ and R ₃ may be the same or different. )

(11) Compound represented by the following general formula (11)

Embedded image (In the formula, Ar represents a phenylene group or a biphenylene group;
₁ and R ₂ represent a substituted or unsubstituted aryl group;
Represents an integer of ~ 4. )

(12) Compound represented by the following general formula (12)

Embedded image (In the formula, A ₁ and A ₂ each represent a substituted or unsubstituted aryl group, which may be the same or different. Ar represents a substituted or unsubstituted fused polycyclic hydrocarbon group.)

(13) Compound represented by the following general formula (13)

Embedded image (In the formula, R ₁ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. N is 1, 2, 3
Or, represents an integer of 4, and m represents an integer of 4-n. m is 2
In the above case, R ₁ may be the same or different. R ₂ , R ₃
And R ₄ are a hydrogen atom, an amino group, an alkoxy group, a thioalkoxy group, an aryloxy group, a methylenedioxy group,
Represents a substituted or unsubstituted alkyl group, a halogen atom, or a substituted or unsubstituted aryl group. H is an integer of 1, 2, 3 or 4, and k and l are 1, 2, 3, 4
Or an integer of 5, and when h, k and l are 2 or more, R
₂ , R ₃ and R ₄ may be the same or different. )

(14) Compound represented by the following general formula (14)

Embedded image (Wherein, A ₁ represents a substituted or unsubstituted aromatic hydrocarbon group, A ₂ represents a substituted or unsubstituted aryl group, A ₃ represents a hydrogen atom, a substituted or unsubstituted alkyl group or an aryl group, respectively. M and n are integers of 1 or 2, and m
+ N = 3. However, when m or n is 2, A ₁ , A ₃
Alternatively, A ₂ may be the same or different. )

(15) Compound represented by the following general formula (15)

Embedded image (Wherein R ₁ and R ₂ represent a substituted or unsubstituted aryl group, which may be the same or different, provided that 1,6-
Excludes diaminopyrene compounds. )

(16) Compound represented by the following general formula (16)

Embedded image (In the formula, R ₁ and R ₂ represent a substituted or unsubstituted aryl group.)

(17) Compound represented by the following general formula (17)

Embedded image (Wherein R ₁ and R ₂ represent a hydrogen atom, a halogen atom, a nitro group, a cyano group or a substituted or unsubstituted alkyl group,
R ₃ and R _{4 each} represent a hydrogen atom, a cyano group, an alkoxycarbonyl group or a substituted or unsubstituted alkyl group, and R ₅ represents a hydrogen atom, a lower alkyl group or an alkoxy group, respectively. W represents a hydrogen atom or a substituted or unsubstituted alkyl group; j is 1 to 5, k is 1 to 4, l is 0 to 2, m
Represents 1 or 2 and n represents an integer of 1 to 3, respectively. )

These charge transporting materials may be used alone or as a mixture of two or more kinds.
And / or good results can be obtained when the one represented by (2) is used.

As the binder resin, polystyrene,
Styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer,
Polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, polyalate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N- Thermoplastic or thermosetting resins such as vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, and alkyd resin. Among these binder resins, polycarbonate containing bisphenol A, bisphenol C, and bisphenol Z as a bisphenol component can be suitably used.

As the solvent, tetrahydrofuran, dioxane, toluene, monochlorobenzene, dichloroethane, cyclohexanone, methylene chloride and the like are used.

In the present invention, when the content of the charge transporting material contained in the charge transporting layer is 25 to 35% by weight, the effect of the present invention can be exhibited well. The charge transport layer 37
It is found that the thickness of the film is suitably 15 μm or less, and that if the film thickness is more than 15 μm, the sensitivity is substantially reduced.

In the present invention, a plasticizer or a leveling agent may be added to the charge transport layer 37. As a plasticizer,
Those used as plasticizers for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are.
Suitable leveling agents are silicone oils such as dimethyl silicone oil and methyl phenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain. 0 to 1% by weight
Is appropriate.

In the electrophotographic photoreceptor of the present invention, an undercoat layer can be provided between the conductive support 31 and the photosensitive layer. The undercoat layer generally contains a resin as a main component. However, considering that the photosensitive layer is coated thereon with a solvent, these resins are resins having high solvent resistance to general organic solvents. desirable. Examples of such a resin include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, copolymer-soluble nylons, alcohol-soluble resins such as methoxymethylated nylon, polyurethane, melamine resins, phenol resins, alkyd-melamine resins, and epoxy resins. Curable resins that form a three-dimensional network structure, such as resins, are exemplified. Further, a fine powder pigment of a metal oxide exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like may be added to the undercoat layer in order to prevent moiré and reduce residual potential.

These undercoat layers can be formed by using an appropriate solvent and a coating method as in the above-mentioned photosensitive layer. Further, as an undercoat layer of the present invention, a silane coupling agent,
Titanium coupling agents, chromium coupling agents and the like can also be used. In addition, the undercoat layer of the present invention includes A
Anodized 12 ₂ O ₃ , organic substances such as polyparaxylylene (parylene), SiO, SnO ₂ , Ti
Those provided with an inorganic substance such as O ₂ , ITO, CeO ₂ by a vacuum thin film forming method can also be used favorably. In addition, known materials can be used. The thickness of the undercoat layer is 0 to 5 μm
Is appropriate.

In the electrophotographic photosensitive member of the present invention, a protective layer may be provided on the photosensitive layer for the purpose of protecting the photosensitive layer. Materials used for the protective layer include ABS resin and A
CS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallyl sulfone, polybutylene, polybutylene terephthalate, polycarbonate, polyether sulfone, polyethylene, Polyethylene terephthalate, polyimide, acrylic resin, polymethylpentene,
Resins such as polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, polyvinylidene chloride, and epoxy resin. Other protective layers include fluororesins such as polytetrafluoroethylene, silicone resins, and inorganic materials such as titanium oxide, tin oxide, and potassium titanate dispersed in these resins for the purpose of improving abrasion resistance. Can be added.
As a method for forming the protective layer, a normal coating method is employed.
The thickness of the protective layer is suitably about 0.1 to 10 μm. In addition, in addition to the above, a
A known material such as -C, a-SiC can be used as the protective layer.

In the present invention, an intermediate layer can be provided between the photosensitive layer and the protective layer. The intermediate layer generally uses a binder resin as a main component. Examples of these resins include polyamide, alcohol-soluble nylon, water-soluble polyvinyl butyral, polyvinyl butyral, and polyvinyl alcohol. As a method for forming the intermediate layer, a normal coating method is employed as described above. The thickness of the intermediate layer is suitably about 0.05 to 2 μm.

Next, the electrophotographic method and the electrophotographic apparatus of the present invention will be described in detail with reference to the drawings.

FIG. 3 is a schematic diagram for explaining the electrophotographic process and the electrophotographic apparatus of the present invention, and the following modified examples also belong to the category of the present invention.

Referring to FIG. 3, this electrophotographic apparatus includes a static elimination section 2, a charging charger 3, an eraser 4, an image exposure section, which are close to the upper surface of a drum-shaped photosensitive member 1 and are arranged in a counterclockwise direction along the circumference. Part 5, developing unit 6, pre-transfer charger 7, transfer charger 10, separation charger 11, separation claw 12, pre-cleaning charger 13, fur brush 1
4. A cleaning blade 15 is sequentially provided. Further, a registration roller 8 for feeding the transfer paper 9 between the photoconductor 1 and the transfer charger 10 and the separation charger 11 is additionally provided. The photoreceptor 1 comprises a drum-shaped conductive support and a photosensitive layer in close contact with the upper surface thereof, and rotates counterclockwise.

In the electrophotographic method using the above-described electrophotographic apparatus, the photosensitive member 1 rotates counterclockwise, is negatively (or positively) charged by the charging charger 3, and is exposed to light from the image exposure section 5. Then, an electrostatic latent image is formed on the photoconductor 1. As the transfer means, generally, the above-described charger can be used, but as shown in the figure, a combination of a transfer charger and a separation charger is effective.

Light sources such as the image exposure unit 5 and the neutralizing lamp 2 include a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, and a light emitting diode (LE).
D), a light emitting material such as a semiconductor laser (LD) and electroluminescence (EL) can be used. To irradiate only light in a desired wavelength range, various filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used. Among the light sources used as image exposure sources, a method using coherent light is useful as a means for forming an electrostatic latent image on a photoreceptor in a digital manner, and in particular, a method of scanning LD light with a polygon mirror or a holographic scanner. For example, a method of performing writing using an LED array is preferably used. Such a light source or the like is provided with a process such as a transfer process, a charge removal process, a cleaning process, or a pre-exposure process using light irradiation in addition to the process shown in FIG. Can be used.

In the developing unit 6, the electrostatic latent image is developed by attaching toner onto the photoreceptor 1, and the charged state of the toner image is adjusted by the pre-transfer charger 7, and then transferred onto the transfer paper 9 by the transfer charger 10. The toner image is transferred, the electrostatic adhesion between the photoconductor 1 and the transfer paper 9 is eliminated by the separation charger 11, and the transfer paper 9 is separated from the photoconductor 1 by the separation claw 12. After the transfer paper 9 is separated, the surface of the photoconductor 1 is cleaned by the pre-cleaning charger 13, the fur brush 14, and the cleaning blade 15. This cleaning can also be performed by removing the remaining toner using only the cleaning blade 15.

When an image is exposed by applying negative (or positive) charge to an electrophotographic photosensitive member, a negative (or positive) electrostatic latent image is formed on the surface of the photosensitive member. If this is developed with a positively (or negatively) charged toner, a positive image can be obtained. Conversely, if it is developed with a negatively (or positively) charged toner, a negative image can be obtained. A known method is applied to the developing means, and a known method is also used for the charge removing means.

In this example, the conductive support is shown as a drum, but a sheet or an endless belt may be used. As the pre-cleaning charger, known charging means such as a corotron, a scorotron, a solid state charger (solid state charger), a charging roller and the like can be used. Further, the above-mentioned charging means can be usually used for the transfer charger and the separation charger. However, as shown in FIG. 3, a charger in which the transfer charger and the separation charger are integrated is efficient and preferable. As the cleaning member, known members such as a blade, a fur brush, a mag fur brush and the like can be used.

FIG. 4 is a schematic diagram illustrating another example of the electrophotographic process of the present invention. In this example, the belt-shaped photoconductor 21 is the photoconductor of the present invention, and the driving roller 2
2a or 22b, charging by the charging charger 23, image exposure by the image exposure source 24, development (not shown), transfer by the transfer charger 25, exposure before cleaning by the exposure unit 26 before cleaning, cleaning by the cleaning brush 27, A series of image formations including the charge removal by the charge removal light source 28 is repeatedly performed. In this case, the exposure of the exposed portion before cleaning is performed from the conductive support side of the photoconductor 21. Of course, in this case, the conductive support is translucent.

The above illustrated electrophotographic process is an example of the embodiment of the present invention, and other embodiments are of course possible. For example, although the pre-cleaning exposure is performed from the support side in FIG. 4, the exposure may be performed from the photosensitive layer side, or the image exposure and the charge removal exposure may be performed from the support side.

On the other hand, as the light irradiation step, image exposure, pre-cleaning exposure, and charge removal exposure are shown. In addition, pre-transfer exposure, image exposure pre-exposure, and other known light irradiation steps are provided. The photoreceptor can be irradiated with light.

The image forming means of the present invention as described above may be fixedly incorporated in an apparatus such as a copying machine, a facsimile, a printer or the like, but may be incorporated in such an apparatus in the form of a process cartridge. Is also good. The process cartridge is one device (part) that includes a photoconductor and further includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a charge removing unit. Although there are many shapes and the like of the process cartridge, a general example is shown in FIG. The process cartridge shown in FIG. 5 includes a charging charger 17, a cleaning brush 18,
It has a compact structure including the image exposure section 19, the developing roller 20, and the like.

[0060]

The present invention will be described below with reference to examples.
The present invention is not limited by these embodiments. All parts are parts by weight.

Examples 1 to 3 and Comparative Examples 1 to 4 After forming an oxide film by anodic oxidation, a coating solution and a charge transport layer of the following composition were formed on an aluminum cylinder which had been subjected to a sealing treatment by a conventional method. The coating solution was sequentially applied and dried, and a charge generating layer having a dry film thickness of 0.2 μm and a charge transport layer having a dry film thickness of 14 μm were provided to produce a laminated photoreceptor.

<Coating solution for charge generation layer> 3 parts of titanyl phthalocyanine 1 part of polyvinyl butyral 80 parts of tetrahydrofuran 70 parts of ethyl cellosolve 70 parts

<Charge Transport Layer Coating Solution> Charge transport material having the following structural formula

Embedded image Polycarbonate Amount shown in Table 1 Tetrahydrofuran 80 parts

[0064]

[Table 1]

Comparative Example 5 A compound having the following structure was used as a charge transporting material.
Comparative Example 5 A photoconductor was prepared in the same manner as in Example 2.

Embedded image

Each of the above electrophotographic photosensitive members was mounted in the electrophotographic process shown in FIG. 3 (however, the image exposure light source was set to 680 n).
m), and a probe of a surface voltmeter was inserted so that the surface potential of the photoconductor immediately before development could be measured. However, the scorotron charger used as the charger was set so that the grid voltage was -400 V and the maximum surface potential of the photoconductor was lower than -400 V. Printing was continuously performed on 8,000 sheets, and the surface potentials of the image-exposed portion and the image non-exposed portion at that time were measured initially and after 8,000 sheets. Table 2 shows the results. Further, the film thickness of the photosensitive layer after continuous copying was measured by an eddy current type film thickness meter.

[0067]

[Table 2]

Examples 4 to 6 and Comparative Examples 6 and 7 On the electroformed nickel belt, an undercoat layer coating solution having the following composition, a charge generation layer coating solution having the following composition, and a charge transport layer coating having the following composition were provided. The solution is applied and dried sequentially, and the dried film thickness is 1.5 μm.
A sublayer, a 0.3 μm charge generation layer and charge transport layers of various thicknesses were provided to produce a laminated photoreceptor. The dry film thickness of the charge transport layer is shown in Table 3.

<Coating solution for undercoat layer> Titanium dioxide powder 5 parts Alcohol-soluble nylon 4 parts Methanol 40 parts Isopropanol 30 parts

<Coating solution for charge generation layer> Titanyl phthalocyanine 3 parts Polyvinyl butyral 2 parts Cyclohexanone 80 parts

<Coating Solution for Charge Transport Layer> Polycarbonate 7 parts Charge transport material described below 3 parts

Embedded image 70 parts of tetrahydrofuran

Comparative Example 8 A compound having the following structure was used as a charge transporting material.
A photoconductor of Comparative Example 8 was produced in the same manner as in Example 5.

Embedded image

The electrophotographic photosensitive members obtained in Examples 4 to 6 and Comparative Examples 6 to 8 were mounted in the electrophotographic process shown in FIG. 4 (however, there was no pre-cleaning exposure), and the image exposure light source was 780 nm. As a semiconductor laser (image writing by a polygon mirror), a probe of a surface voltmeter was inserted so that the surface potential of the photoconductor immediately before development could be measured. However, the grid voltage was adjusted by the scorotron charger used as the charger so that the initial electric field strength (absolute value) of the photoreceptor was 2.5 × 10 ⁵ V / cm or less. Printing was continuously performed on 6,000 sheets, and the surface potentials of the image-exposed area and the image non-exposed area at that time were measured at the initial stage and after 6,000 sheets. Table 3 shows the results.

[0074]

[Table 3]

Examples 7 to 9 and Comparative Examples 9 and 10 On the same aluminum substrate as in Example 1, a coating solution for the charge generation layer having the following composition and a coating solution for the charge transport layer having the following composition were sequentially applied and dried. Thus, a charge generation layer of 0.2 μm and a charge transport layer of 15 μm were formed, and five same electrophotographic photosensitive members were produced.

<Coating Solution for Charge Generating Layer> 2 parts of titanyl phthalocyanine 1.5 parts of polyvinyl butyral 200 parts of benzene

<Charge Transport Layer Coating Solution> Polycarbonate 10 parts Charge transport material having the following structural formula 7 parts

Embedded image 80 parts of methylene chloride

Comparative Example 11 A compound having the following structure was used as a charge transporting material.
A photoconductor of Comparative Example 11 was produced in the same manner as in Example 8.

Embedded image

The electrophotographic photosensitive members obtained in Examples 7 to 9 and Comparative Examples 9 to 11 were mounted on an electrophotographic process cartridge shown in FIG. 5, and then mounted on an image forming apparatus. However, a 780 nm semiconductor laser (image writing by a polygon mirror) was used as an image exposure light source, and a probe of a surface voltmeter was inserted so that the surface potential of the photoconductor immediately before development could be measured. However, the charging roller was used to charge the photoconductor, and the electric field intensity was changed as shown in Table 4 by changing the applied voltage. Printing was continuously performed on 5,000 sheets, and the surface potentials of the image-exposed area and the image non-exposed area at that time were measured at the initial stage and after 5,000 sheets. Table 4 shows the results.

[0080]

[Table 4]

[0081]

According to the electrophotographic photoreceptors of claims 1 to 3, a charge generation layer containing an intrinsic charge generation material as a main component and a triarylamine or a derivative thereof as a charge transport material on a conductive substrate. In the electrophotographic photoreceptor obtained by laminating a charge transport layer containing the charge transport layer, the content of the charge transport material in the charge transport layer is 25 to 35% by weight, and the thickness of the charge transport layer is 15 μm or less. Accordingly, there is provided an electrophotographic photoreceptor having a charge transport layer having excellent film-forming properties and excellent abrasion resistance, which has not been realized conventionally, and having high sensitivity in the past.

According to the electrophotographic method of the present invention, the electrophotographic photoreceptor of the present invention is applied to the electrophotographic method in which at least charging, image exposure, development, transfer, cleaning and charge removal are repeated. Since the applied maximum electric field strength is 300,000 V / cm or less, an electrophotographic method excellent in the repetitive use characteristics of the photoconductor is provided.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an electrophotographic photosensitive member used in the present invention.

FIG. 2 is a schematic sectional view of another electrophotographic photosensitive member used in the present invention.

FIG. 3 is a schematic diagram for explaining the electrophotographic apparatus of the present invention.

FIG. 4 is a schematic diagram for explaining the electrophotographic apparatus of the present invention.

FIG. 5 is a schematic diagram for explaining a typical electrophotographic apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoreceptor 2 Charge removal exposure part (lamp) 3 Charger 4 Eraser 5 Image exposure part 6 Developing unit 7 Charger before transfer 8 Registration roller 9 Transfer paper 10 Transfer charger 11 Separation charger 12 Separation claw 13 Charger before cleaning 14 Fur brush 15 Cleaning Blade 16 Photoconductor 17 Charging charger 18 Cleaning brush 19 Image exposure unit 20 Developing roller 21 Photoconductor 22a, 22b Driving roller 23 Charging charger 24 Image exposure source 25 Transfer charger 26 Pre-cleaning exposure unit 27 Cleaning brush 28 Static elimination light source 31 Conductive support Body 35 Charge generation layer 37 Charge transport layer

Claims (4)

[Claims] 1. An electrophotographic photoreceptor comprising a conductive substrate and a charge generation layer containing an intrinsic charge generation material as a main component and a charge transport layer containing a triarylamine or a derivative thereof as a charge transport material. 3. The electrophotographic photosensitive member according to claim 1, wherein the content of the charge transport material in the charge transport layer is 25 to 35% by weight, and the thickness of the charge transport layer is 15 μm or less. 2. The electrophotographic photoconductor according to claim 1, wherein the charge transporting material is a compound selected from the following formulas (1) and / or (2). Embedded image (Wherein, R ₁ and R ₂ represent a hydrogen atom, a substituted or unsubstituted lower alkyl group, or a substituted or unsubstituted aryl group, and R ₃ , R ₄ and Ar ₁ represent a substituted or unsubstituted aryl group Wherein Ar ₂ represents a substituted or unsubstituted arylene group, and Ar ₁ and R ₁ may together form a ring,
N is an integer of 0 or 1. ) (Wherein R ₁ , R ₃ and R ₄ are a hydrogen atom, an amino group, an alkoxy group, a thioalkoxy group, an aryloxy group, a methylenedioxy group, a substituted or unsubstituted alkyl group, a halogen atom, or a substituted or unsubstituted Is an aryl group of R
₂ represents a hydrogen atom, an alkoxy group, a substituted or unsubstituted alkyl group or a halogen atom, respectively. Also, k,
l, m and n are integers of 1, 2, 3 or 4, and when each is an integer of 2, 3 or 4, R ₁ , R ₂ , R ₃ and R ₄ may be the same or different Good. ) 3. The electrophotographic photoreceptor according to claim 1, wherein phthalocyanine is used as the charge generation material. 4. The maximum electric field intensity applied to a photosensitive layer in the electrophotographic method of repeating at least charging, image exposure, development, transfer, cleaning and charge elimination of the electrophotographic photosensitive member according to claim 1, 2 or 3. Is 300,000 V / cm
An electrophotographic method characterized by the following.