JP2003005393A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high sensitivity and high durability electrophotographic photoreceptor containing a graft copolymer having a core/shell structure in a photosensitive layer. SOLUTION: In the electrophotographic photoreceptor containing at least an electric charge generating material and an electric charge transporting material on an electrically conductive support, the top layer contains a graft copolymer having a core/shell structure and the electric charge generating material is a trisazo compound of formula (1) (where R<1> is H, halogen, alkyl, alkoxy or cyano and A is the residue of a coupler).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a highly sensitive and highly durable electrophotographic photoreceptor containing a graft copolymer having a core / shell structure in a photosensitive layer, and an electrophotographic apparatus using the photoreceptor. And a process cartridge.

[0002]

2. Description of the Related Art An electrophotographic method using an electrophotographic photosensitive member applied to a copying machine, a facsimile machine, a laser printer, a direct digital plate making machine, etc. is a process of at least charging, image exposure and development of the electrophotographic photosensitive member. After that, the toner image is transferred to the image carrier (transfer paper), fixed, and the surface of the electrophotographic photosensitive member is cleaned.

Conventionally, as a photoconductor used in the electrophotographic system, a photoconductive layer mainly containing selenium or a selenium alloy is provided on a conductive support, or an inorganic light such as zinc oxide or cadmium sulfide. Those in which a conductive material is dispersed in a binder, and those using an amorphous silicon-based material are generally known, but in recent years, low cost, high degree of freedom in designing a photoconductor, Organic photoconductors have come to be widely used because of their pollution-free property.

For organic electrophotographic photoreceptors, a photoconductive resin represented by polyvinylcarbazole (PVK), P
VK-TNF (2,4,7-trinitrofluorenone)
Known as a charge transfer complex type, a phthalocyanine-binder-type pigment dispersion type, and a function separation type photoconductor in which a charge generating substance and a charge transporting substance are used in combination. The photoconductor of is attracting attention.

The mechanism of forming an electrostatic latent image in the function-separated type photoconductor is that when the photoconductor is charged and then irradiated with light, the light passes through the transparent charge transport layer and is caused by the charge generating substance in the charge generating layer. The charge-generating substance that has been absorbed and absorbs light generates charge carriers, which are injected into the charge-transporting layer and move in the charge-transporting layer according to the electric field generated by charging, so that the charge on the surface of the photoconductor is removed. By neutralizing, an electrostatic latent image is formed. In the function-separated type photoreceptor, it is known and useful to use a charge transporting substance having an absorption mainly in the ultraviolet region and a charge generating substance having an absorption mainly in the visible region in combination.

However, most of the charge-transporting substances of the organic electrophotographic photosensitive member used in the electrophotographic method have been developed as a low molecular weight compound, and the low molecular weight compound alone has no film-forming property, and is therefore generally inactive. Used by being dispersed and mixed in a polymer. However, the charge transport layer consisting of a low molecular weight charge transport material and an inert polymer is generally soft, and when repeatedly used in the electrophotographic process, film scraping is caused by mechanical load on the surface of the photoreceptor due to the developing system or cleaning system. The disadvantage is that it is easily worn and has low wear resistance.

Further, the charge transport layer having this structure has a limit in charge mobility, which has been an obstacle to speeding up or downsizing of the electrophotographic process. This is because the content of the low molecular weight charge transport material is usually 50% by weight or less. That is, the charge mobility can be certainly increased by increasing the content of the low-molecular-weight charge transport material, but on the contrary, at this time, the film forming property and the abrasion resistance are deteriorated.

As a technique for improving the characteristics of the organic photoconductor, a binder resin of the organic photoconductor is improved (JP-A-5-216250) and a charge-transporting polymer (JP-A-51-73888). JP-A-54-8527, JP-A-54-11737, JP-A-56-1
No. 5,0749, JP-A-57-78402, JP-A-63-285552, and JP-A-64-1728.
JP-A-64-13061, JP-A-64-
No. 19049, No. 3-50555, No. 4-175337, No. 4-225014, No. 4-230767, No. 5-23.
2727, JP-A-5-310904, etc.) are noted and disclosed.

In the above publication, it is difficult to improve the abrasion resistance of the improved charge transfer layer binder resin due to the composition ratio of the low molecular weight charge transfer material. On the other hand, the one using the charge transporting polymer can improve the film scraping by polymerizing the charge transporting layer component, but to treat the photoconductor as a stationary part that does not replace until the mechanical life,
It is still not sufficient and further improvement is needed.

On the other hand, Japanese Patent Laid-Open No. 07-295248,
JP-A-07-301936, JP-A-08-082
Japanese Patent Publication No. 940 and the like propose that the surface layer contains a fluorine-modified silicone oil to improve the surface property, improve the cleaning property, and improve the abrasion resistance of the photoreceptor surface. However, when it is attempted to contain the fluorine-modified silicone oil in the surface layer, the fluorine-modified silicone oil moves to the vicinity of the surface and concentrates near the surface during the surface layer formation process. The effect is lost early.

Various attempts have also been made for systems in which fine particles are added for the purpose of improving wear resistance. For example, silicone resin particles, fluorine-containing resin particles (JP-A-63-65449), melamine resin particles (JP-A-60-177349), and the like are added. Japanese Unexamined Patent Publication No. 02-143257 proposes that the surface layer contains polyethylene powder to lower the friction coefficient of the surface layer to improve the cleaning property and the abrasion resistance of the photoconductor. Further, Japanese Patent Application Laid-Open No. 02-144550 proposes to include a fluorine-containing resin powder in the surface layer to reduce the friction coefficient of the surface layer, improve the cleaning property, and improve the abrasion resistance of the photoreceptor. is there. In addition, JP-A-07-
Japanese Patent No. 128872 and Japanese Patent Application Laid-Open No. 10-254160 propose that the surface layer contains silicone fine particles to reduce the friction coefficient of the surface layer and improve the cleaning property to improve the abrasion resistance of the photoconductor. In addition, JP-A-200
0-010322 and USP 5,998,07
No. 2 proposes that the surface layer contains cross-linked organic fine particles to reduce the friction coefficient of the surface layer, improve the cleaning property, and improve the abrasion resistance of the photoreceptor. Furthermore, JP-A-08
Japanese Patent Laid-Open No. 190213 proposes that the surface layer contains fine particles of methylsiloxane resin to reduce the friction coefficient of the surface layer, improve the cleaning property, and improve the abrasion resistance of the photoconductor.

These proposals are intended to achieve high durability by adding functions such as reduction of the friction coefficient of the surface of the photoconductor and reduction of surface energy, but they have the following problems.
That is, when the resin powder or fine particles are dispersed in the surface layer to improve the abrasion resistance of the surface of the photosensitive layer, the compatibility with the binder resin is poor and the dispersion of the resin powder or fine particles becomes poor, so that the image There is a problem that abnormal defects such as black spots and white spots occur during formation, and the residual potential rises during repeated use. At the same time, the problem that the light transmittance of the photosensitive layer is impeded, the sensitivity is lowered, the charge transport performance is lowered, and the image density becomes nonuniform is not solved.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional state of the art, and a core is formed in an image forming member such as an electrophotographic photoreceptor, a transfer belt and a fixing belt.
/ It is intended to provide a highly durable member by containing a graft copolymer having a shell structure. Another object is to provide a highly sensitive and highly durable electrophotographic photoreceptor.

[0014]

Means for Solving the Problems As a result of intensive investigations by the present inventors, it has been found that the above problems can be solved by using an image forming member containing a graft copolymer having a core / shell structure as an active ingredient. Heading, the present invention was reached.

That is, the present invention is the following (1) to (14). (1) In an electrophotographic photoreceptor containing at least a charge generating material and a charge transporting material on a conductive support, the outermost layer thereof contains a graft copolymer having a core / shell structure, and the charge generating material is An electrophotographic photoreceptor, which is a trisazo compound represented by the general formula (1).

[0016]

[Chemical 21] (However, in the general formula 1, R ¹ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or a cyano group, and
Represents a coupler residue. )

(2) The coupler residue A in the trisazo compound of the above general formula (1) is represented by the following general formula (2) to
The electrophotographic photoreceptor according to (1) above, which is selected from the residues represented by (7).

[0018]

[Chemical formula 22]

[Wherein X ¹ , Y ¹ and Z in the above formula represent the following, respectively. ^{X 1: -OH, -N (R} 2)
(R ³⁾ or, -NHSO ₂ -R ^4. (R ² and R ³ represent a hydrogen atom, an acyl group or a substituted or unsubstituted alkyl group, and R ⁴ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group.) Y ¹ : hydrogen atom A halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a carboxy group, a sulfone group, a benzimidazolyl group, a substituted or unsubstituted sulfamoyl group, a substituted or unsubstituted allofanoyl group or -CO
It represents N (R ⁵ ) (Y ² ). {R ⁵ represents a hydrogen atom, an alkyl group or a substituted product thereof, a phenyl group or a substituted product thereof, and Y ² represents a hydrocarbon ring group or a substituted product thereof, a heterocyclic group or a substituted product thereof, or -N = C.
(R ⁶ ) (R ⁷ ) (wherein R ⁶ is a hydrocarbon ring group or a substituted product thereof, a heterocyclic group or a substituted product thereof, or a styryl group or a substituted product thereof, and R ⁷ is a hydrogen atom, an alkyl group or a substituted product thereof. Or a phenyl group or a substituted form thereof, or R6 and R7 may form a ring together with the carbon atom bonded to them. } Z: Hydrocarbon ring group or a substituted body thereof, or heterocyclic group or a substituted body thereof. ]

[0020]

[Chemical formula 23] (In the above formula, R ⁸ represents a substituted or unsubstituted hydrocarbon group.)

[0021]

[Chemical formula 24] (In the above formula, R ⁹ represents a substituted or unsubstituted hydrocarbon group.)

[0022]

[Chemical 25] (In the above formula, R ¹⁰ represents an alkyl group, a carbamoyl group, a carboxyl group or an ester thereof, and Ar ¹ represents a substituted or unsubstituted aromatic hydrocarbon group.)

[0023]

[Chemical formula 26] (In the above formula, X ² represents an aromatic hydrocarbon divalent group or a heterocyclic divalent group.)

[0024]

[Chemical 27] (In the above formula, X ² represents an aromatic hydrocarbon divalent group or a heterocyclic divalent group.)

(3) The trisazo compound is represented by the following formula (8)
The electrophotographic photoreceptor according to (1) above, which is a compound represented by:

[0026]

[Chemical 28]

(4) In an electrophotographic photoreceptor containing at least a charge-generating material and a charge-transporting material on a conductive support, the outermost layer of the photoreceptor contains a graft copolymer having a core / shell structure, and the charge-generating material is used. The material is the following general formula (9)
A photoconductor for electrophotography, which is a bisazo compound represented by:

[0028]

[Chemical 29] (In the formula, R ¹¹ and R ¹² are a hydrogen atom, a halogen atom,
It represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a cyano group or a nitro group and may be the same or different. B and C represent a coupler residue and may be the same or different. Specifically, it is defined in the same manner as the coupler residue A shown in claim 2. )

(5) The bisazo compound is represented by the following formula (10)
The electrophotographic photoreceptor according to (4) above, which is a bisazo compound represented by:

[0030]

[Chemical 30]

(6) The bisazo compound is represented by the following formula (11)
The electrophotographic photoreceptor according to (4) above, which is a bisazo compound represented by:

[0032]

[Chemical 31]

(7) An electrophotographic photoreceptor containing at least a charge generating material and a charge transporting material on a conductive support, the outermost layer of which contains a graft copolymer having a core / shell structure, The material is the following general formula (1
An electrophotographic photoreceptor, which is a bisazo compound represented by 2).

[Chemical 32] (In the formula, D and E represent a coupler residue and may be the same or different. Specifically, they are defined in the same manner as the coupler residue A shown in the above (2).)

(8) The bisazo compound is represented by the following formula (13)
The electrophotographic photoreceptor according to (7) above, which is a bisazo compound represented by:

[Chemical 33]

(9) In an electrophotographic photoreceptor containing at least a charge-generating material and a charge-transporting material on a conductive support, the outermost layer thereof contains a graft copolymer having a core / shell structure, and the charge-generating material is used. The material is the following general formula (1
An electrophotographic photoreceptor, which is a phthalocyanine compound represented by 4).

[Chemical 34] [In the formula, M represents a metal or, in the absence of a metal, represents two hydrogen atoms. ]

(10) In an electrophotographic photoreceptor containing at least a charge generating material and a charge transporting material on a conductive support, the outermost layer thereof contains a graft copolymer having a core / shell structure, An electrophotographic photoreceptor, wherein the material is a mixture of two or more compounds represented by the general formulas (1), (9), (12) and (14).

(11) In an electrophotographic photoreceptor containing at least a charge generating material and a charge transporting material on a conductive support, the outermost layer thereof contains a graft copolymer having a core / shell structure, The material is the following general formula (1
An electrophotographic photoreceptor, which is an α-phenylstilbene derivative represented by 5).

[0038]

[Chemical 35]

(In the formula, n is an integer of 0 or 1, Ar ⁵ and A
r ⁶ represents a substituted or unsubstituted aryl group (except in the case of an unsubstituted phenyl group at the same time) or a group which forms a ring together, and Ar ⁷ represents a substituted or unsubstituted aryl group. R ¹⁶ , R ¹⁷ and R ¹⁸ represent a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, and the aryl group and the arylene group have substituents such as an alkoxy group, a phenoxy group and an alkyl group. ,
It is a hydroxy group, a halogen atom, a cyano group, or a nitro group. )

(12) The electrophotographic photoreceptor according to (11) above, wherein the α-phenylstilbene derivative is an α-phenylstilbene derivative represented by the following general formula (16).

[0041]

[Chemical 36] (In the formula, R ¹⁹ represents a hydrogen atom, an alkyl group, an alkoxy group,
Alternatively, it represents a halogen atom. )

(13) In an electrophotographic photoreceptor containing at least a charge-generating material and a charge-transporting material on a conductive support, the outermost layer thereof contains a graft copolymer having a core / shell structure, The material is the following general formula (1
An electrophotographic photoreceptor, which is a benzidine compound represented by 7).

[0043]

[Chemical 37] (In the formula, R ²⁰ represents a lower alkyl group, a lower alkoxy group or a halogen atom, R ²¹ and R ²² may be the same or different, and represent a hydrogen atom, a lower alkyl group, a lower alkoxy group or a halogen atom, h, l, and m represent the integer of 0-4.)

(14) In an electrophotographic photoreceptor containing at least a charge generating material and a charge transporting material on a conductive support, the outermost layer thereof contains a graft copolymer having a core / shell structure, A photosensitive material for electrophotography, wherein the conductive material is a charge-transporting polymer having a triarylamine structure represented by the following general formula (18).

[0045]

[Chemical 38]

[In the formula, Ar ¹ , Ar ² and Ar ³ represent a substituted or unsubstituted arylene group. R ¹ and R ² represent the same or different acyl groups, substituted or unsubstituted alkyl groups, and substituted or unsubstituted aryl groups. k is 5 to 5000
Is an integer of 5 to 5000, and 0 <k / (k + j)
≦ 1. X is a substituted or unsubstituted aliphatic divalent group, a substituted or unsubstituted cycloaliphatic divalent group, a substituted or unsubstituted aromatic divalent group, or a divalent group formed by linking these, or Show what is represented. ]

[0047]

[Chemical Formula 39]

(Here, R ³ , R ⁴ , R ⁵ and R ⁶ are independently a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group or a halogen atom.
Are each independently an integer of 0 to 4, c and d are each independently an integer of 0 to 3, and are the same when a plurality of R ³ , R ⁴ , R ⁵ and R ⁶ are present. But it can be different. Y
Is a single bond, a linear alkylene group having 2 to 12 carbon atoms,
A substituted or unsubstituted branched alkylene group having 3 to 12 carbon atoms, a divalent group composed of one or more alkylene groups having 1 to 10 carbon atoms and one or more oxygen atom and sulfur atom,
-O-, -S-, -SO-, -SO _2- , -CO-, -COO-, or

[0049]

[Chemical 40]

Z ¹ and Z ^{2 each} represent a substituted or unsubstituted aliphatic divalent group or a substituted or unsubstituted arylene group, and R ⁷ and R ¹⁴ are a halogen atom, a substituted or unsubstituted alkyl group. A group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, R ⁸ ,
R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , and R ¹³ are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group,
It represents a substituted or unsubstituted alkoxy group or a substituted or unsubstituted aryl group. R ⁸ and R ⁹ may combine to form a carbon ring having 5 to 12 carbon atoms, R ¹⁵ and R ¹⁶ represent a single bond or an alkylene group having 1 to 4 carbon atoms, and R ¹⁷ and R ¹⁸ Each independently represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, e and g are integers from 0 to 4, f is 1 or 2, h is an integer from 0 to 20, and i is 0. Represents an integer from ~ 2000. )

[0051]

BEST MODE FOR CARRYING OUT THE INVENTION The graft copolymer having a core / shell structure used in the present invention (hereinafter, also referred to as "core / shell graft copolymer") will be described in detail below. The graft copolymer having a core / shell structure used in the present invention is, for example, one kind or two or more kinds of vinyl monomers are polymerized in various rubber-like polymers by a radical polymerization technique in one step or in multiple steps. Can be obtained by Examples of the rubber-like polymer here include polybutadiene, styrene-butadiene block copolymer rubber, styrene-butadiene random copolymer rubber, acrylonitrile-butadiene block copolymer rubber, and saturated hydrogenated or partially hydrogenated diene rubber. Examples thereof include rubber, isoprene rubber, chloroprene rubber, natural rubber, silicone rubber, ethylene-propylene-diene monomer terpolymer, acrylic rubber and acrylic-silicone composite rubber. The above various rubber components may be mixed and used, but in the present invention, acrylic-silicone composite rubber is particularly preferable.

A method by emulsion polymerization is preferable for forming the rubber-like polymer. A crosslinkable monomer may be used as the rubber-like polymer. Examples of the crosslinkable monomer include aromatic divinyl compounds such as divinylbenzene, alkane polyol polyacrylates such as ethylene glycol diacrylate and ethylene glycol dimethacrylate, or allyl compounds such as alkane polyol polymethacrylate and allyl methacrylate. .

The above-mentioned acrylic-silicone composite rubber means a composite rubber having a structure in which the polyorganosiloxane rubber component and the polyalkyl (meth) acrylate rubber component are intertwined with each other so that they cannot be separated. More specifically, various cyclic organosiloxanes having three or more members, such as hexamethylcyclotrisiloxane,
A latex of polyorganosiloxane rubber is prepared by emulsion polymerization using octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, etc., and a crosslinking agent and / or a graft crossing agent, and then an alkyl (meth) acrylate monomer and crosslinking are prepared. It is a composite rubber obtained by impregnating a latex of polyorganosiloxane rubber with an agent and a graft crossing agent and then polymerizing the latex. Examples of the alkyl (meth) acrylate monomer used here include alkyl acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate, and alkyls such as hexyl methacrylate and 2-ethylhexyl methacrylate. Methacrylate is mentioned, but it is particularly preferable to use n-butyl acrylate.

When the polyorganosiloxane rubber component exceeds 90% by weight during compounding, the surface appearance of the composition obtained by adding the graft copolymer using this compound rubber to the resin deteriorates. In particular, when the polyalkyl (meth) acrylate rubber component exceeds 90% by weight, the effect of improving the wear resistance and impact resistance of the obtained graft copolymer decreases. Therefore, in the composite rubber used in the present invention, the two rubber components constituting the composite are both 10 to 90% by weight.
It is necessary to be in the range of (total amount of both rubber components 100% by weight), and preferably in the range of 20 to 80% by weight.

The average particle size of the composite rubber is 0.01 to
1.0 μm, preferably 0.08 to 0.6 μm. If the average particle diameter is less than 0.01 μm, the effect of improving the wear resistance and impact resistance of the obtained graft copolymer is reduced, and
If it is larger than 0 μm, the abrasion resistance of the graft copolymer,
The impact resistance improving effect decreases and the surface appearance of the composition obtained by adding the graft copolymer to the resin deteriorates.
The production of the acrylic-silicone composite rubber is described in detail in JP-B-8-30102 (Mitsubishi Rayon Co., Ltd.).

The various rubber-like polymers obtained as described above are used in the present invention by polymerizing one or more vinyl-based monomers in a single stage or multiple stages by a radical polymerization technique. A graft copolymer having a core / shell structure is obtained. Further, it may be a mixture with a copolymer containing only a graft component produced as a by-product during the production.

Vinyl-based monomers to be graft-polymerized with various rubber-like polymers include styrene, α-methylstyrene, methyl (o-, m-, p-) styrene, ethylstyrene, isobutylstyrene, tert-butyl. Aromatic vinyl compounds such as styrene, bromostyrene, vinylnaphthalene, vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, methyl methacrylate, 2-ethylhexyl methacrylate, ethyl methacrylate, propyl methacrylate, hydroxyethyl methacrylate,
Examples thereof include alkyl methacrylic acid esters such as cyclohexyl methacrylate and butyl methacrylate, acrylic acid esters such as methyl acrylate, ethyl acrylate, and butyl acrylate.
Used in combination of two or more species.

Using the above-mentioned acrylic-silicone composite rubber as the rubber-like polymer, a composite rubber system obtained by polymerizing one or more vinyl monomers in a single stage or in a multistage by a radical polymerization technique. Better abrasion resistance when using core / shell copolymers,
It has impact resistance and can be preferably used. This composite rubber-based core / shell copolymer is produced by the same method as described above, but more specifically by the method described in JP-B-8-30102 (Mitsubishi Rayon Co., Ltd.).

The weight ratio of the rubber-like polymer (core layer) to the vinyl-based monomer (shell layer) is 30 to 95 for the core layer based on 100 parts by weight of the entire core / shell graft copolymer.
The shell layer is preferably 5 to 70 parts by weight, the core layer is 40 to 90 parts by weight, and the shell layer is 10 to 60 parts by weight.
More preferably, it is parts by weight. When the shell layer is less than 5 parts by weight, the core / shell graft copolymer is not sufficiently dispersed in the resin, and when it exceeds 70 parts by weight, the impact strength is insufficiently expressed, which is not preferable.

The average particle size of the core / shell graft copolymer thus obtained is preferably 0.05 to 5 μm. If it is less than 0.05 μm, the impact resistance and abrasion resistance are not sufficiently improved, and if the particle size is more than 5 μm, the appearance of the molding surface is impaired and the impact resistance and abrasion resistance are not sufficiently improved.

In the core / shell graft copolymer used in the present invention, the residual of impurities such as an emulsifying agent and a coagulant used during polymerization has a problem with electric characteristics. Therefore, it is preferable to purify the product as necessary before use. Examples of the purification method include a method of stirring and washing with an acid, an alkaline aqueous solution, water and alcohol, and a solid-liquid extraction method such as Soxhlet extraction.

The amount of the graft copolymer having such a core / shell structure used in the image forming member can be arbitrarily selected in consideration of the surface appearance, impact resistance and abrasion resistance depending on the matrix resin used. When used as a photoreceptor, the proportion in the photosensitive layer is 20% by weight or less, more preferably 10% by weight or less. 20% by weight
When used as described above, side effects such as a decrease in surface smoothness of the photoconductor and an increase in residual potential are brought about.

As a method for adding the graft copolymer having a core / shell structure to the resin, a method such as stirring in a general-purpose solvent, ball milling method, vibration milling method, ultrasonic method, or the like is used. You can Or
Examples thereof include a method of mechanically mixing using a known apparatus such as a Banbury mixer, a roll mill, a twin-screw extruder, and shaping into pellets. The extrusion-shaped pellets can be molded in a wide temperature range, and a normal injection molding machine is used for molding. The pellet-shaped graft copolymer having a core / shell structure and the resin can be further applied to the above-mentioned solution dispersion method.

Typical examples of the graft copolymer having a core / shell structure used in the present invention are shown below. For example, Kane Ace B series from Kanegafuchi Chemical Industry Co., Ltd., Metabrene C series from Mitsubishi Rayon Co., Ltd., Metabrene S
Series, Metabrene W Series, Kureha Chemical Industry Co., Ltd.
Paraloid EXL series, HIA series, BTA
Series, KCA series, Hybrene B621 from Zeon Corporation, Stafloyd from Takeda Pharmaceutical Co., Ltd., BLENDEX980 from General Electric Co., KM334, KM330 from Rohm and Haas Co., DURASTRENGTH 20 from El Fatatchem Co., Ltd.
0, METABLEN S-2001, Kaneka Texas Corporation's FM10, FM20, and the like, which are commercially available, but are not limited to these. Further, among these graft copolymers having a core / shell structure, the METABLEN S series manufactured by Mitsubishi Rayon Co., Ltd. in which a rubber-like polymer (core layer) is composited is particularly preferable. In addition, JP-A-1
A core-shell body having a core of colloidal silica and a shell of polyorganosiloxane described in JP-A-0-182841, and a copolymer obtained by graft-copolymerizing a vinyl monomer, an organic solvent described in JP-A-5-209027, or A graft copolymer having a core / shell structure, which is obtained by treating the surface of colloidal silica having water dispersibility with an alkoxysilane compound and then substituting the dispersion medium with a radically polymerizable vinyl compound and polymerizing it, may also be used. You can

The graft copolymer having a core / shell structure used in the electrophotographic photoreceptor of the present invention has been described above. An embodiment in which the graft copolymer is contained in the electrophotographic photoreceptor will be described below. .

Cross-sectional views of the photoconductor of the present invention are shown in FIGS. The photoreceptor of the present invention comprises a core / shell graft copolymer and a photosensitive layer 2, 2 ′, 2 ″, 2 ″ ′, 2 ″ ″, 2 ″ ″ ′,
Although it is contained in 2 """, it can be used as shown in FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 5, FIG. 6 or FIG.

The photoreceptor shown in FIG. 1 comprises a charge-generating substance 5 and a core / shell graft copolymer 3 on a conductive support 1, which is a resin having a charge-transporting ability alone or a combination of the resin and a binder. The photosensitive layer 2 dispersed in the transport medium 4 is provided. The resin having a charge transporting ability here alone or in combination with a binder forms a charge transporting medium, while the charge generating substance 5 (charge generating substance such as an inorganic or organic pigment) generates a charge carrier. . In this case, the charge transport medium 4 is mainly responsible for receiving the charge carriers generated by the charge generating substance 5 and transporting them. The basic condition of this photoreceptor is that the charge-generating substance and the resin having charge-transporting ability do not overlap each other in the absorption wavelength region, mainly in the visible region. This is because in order to efficiently generate charge carriers in the charge generating substance 5, it is necessary to transmit light to the surface of the charge generating substance. The charge transport medium 4 may contain a low molecular charge transport substance, or a charge transport medium composed of a low molecular charge transport substance and a binder may be used.

The photoconductor in FIG. 2 has a protective layer 6 provided on the charge transport layer 4. In the case of this constitution, a resin having a charge transporting ability or a combination of the resin and a binder is used on the charge transporting layer 4, and the core / shell graft copolymer 3 is contained therein.
Is added to form the protective layer 6. A protective layer composed of a low molecular weight charge transport material, a binder and a core / shell graft copolymer can also be used. It is also possible to form a protective layer containing no charge transport material, that is, a binder and a core / shell graft copolymer.

The photoconductor in FIG. 3 comprises a charge generating layer 7 mainly composed of a charge generating substance 5 on a conductive support 1, a charge transporting resin containing a resin having a charge transporting ability and a core / shell graft copolymer 3. It is provided with a photosensitive layer 2 ″ composed of a laminate with a layer 4. In this photoreceptor, the light transmitted through the charge transport layer 4 reaches the charge generation layer 7, where charge carriers are generated, On the other hand, the charge transport layer 4 receives and injects charge carriers and transports the charge carriers. The charge carriers required for light attenuation are generated by the charge generating substance 5, and the charge carriers are transported by the charge transport layer 4. Such a mechanism is the same as that described for the photoconductor shown in Fig. 1. The charge transport medium 4 is formed by a resin having a charge transport ability alone or in combination with a binder. Charge generation layer 7 A resin having a charge transporting ability or a low molecular weight charge transporting substance may be contained in the photosensitive layer 2 ″ for the same purpose.
A charge transport layer medium composed of a low molecular weight charge transport material and a binder can also be used. The same applies to the photosensitive layers 2 "'to 2""" described later.

The photoconductor in FIG. 4 has a protective layer 6 provided on the charge transport layer 4 containing no core / shell graft copolymer by the same method as in FIG. The charge transport layer may contain a core / shell graft copolymer.

The photoreceptor in FIG. 5 comprises the charge generation layer 7 of FIG. 3 containing a core / shell graft copolymer, and a charge transporting resin or a low molecular weight charge transport material and a charge containing a composition of a binder. This is a photoconductor in which the stacking order of the transport layers 4 is reversed.

The photoreceptor shown in FIG. 6 has a protective layer 6 formed on the charge generation layer 7 containing no core / shell structured graft copolymer in the same manner as in FIG. The charge generation layer 7 may contain a core / shell graft copolymer.

The photosensitive member in FIG. 7 is a graft copolymer having a core / shell structure on a conductive support 1, a sensitizing agent and a resin having a charge transporting ability, alone or in combination with a binder, or a low molecular charge transporting substance. It is provided with a photosensitive layer 2 """formed of a binder and a resin or a low molecular weight charge transport material having a charge transporting function, which acts as a photoconductive material and is required for light attenuation. The generation and transfer of charge carriers are carried out through a resin or a low molecular weight charge transporting substance having a charge transporting ability, however, a resin or a low molecular weight charge transporting substance having a charge transporting ability has almost the absorption in the visible region of light. Therefore, for the purpose of forming an image with visible light, it is necessary to add a sensitizing dye having absorption in the visible region for sensitization.

In order to produce the photoreceptor shown in FIG. 1, the core / shell graft copolymer 3 and the charge generation are added to a solution prepared by dissolving one or more kinds of resins or binders having a charge transporting ability in combination. Fine particles of the substance 5 may be dispersed, coated on the conductive support 1 and dried to form the photosensitive layer 2. The thickness of the photosensitive layer is 3 to 50 μm, preferably 5 to 40
μm is suitable. The amount of the binder in the photosensitive layer 2 is 30
~ 95% by weight. The content of the core / shell graft copolymer therein is 20% by weight or less, preferably 10% by weight or less, based on the solid content in the photosensitive layer 2. Further, instead of the resin having charge transporting ability, a composition comprising a low molecular weight charge transporting material and a binder can be applied.

The amount of the charge generating substance 3 in the photosensitive layer 2 is 0.1 to 50% by weight, preferably 1 to 20% by weight. As the charge generating substance 3, general formulas (1), (9),
The method for producing the azo compound represented by (12) and specific compound examples are described in JP-A-53-132347, respectively.
Japanese Patent Application Laid-Open No. 54-22834, Japanese Patent Application No. 2-2
48708 and JP-A-53-133445.

Details of the phthalocyanine pigment represented by the general formula (14) will be described. In the formula, M represents a metal,
In the case of a metal-free phthalocyanine in which no metal is present, it represents two hydrogen atoms.

[0077]

[Chemical 41]

M (central metal) mentioned here is H,
Li, Be, Na, Mg, Al, Si, K, Ca, S
c, Ti, V, Cr, Mn, Fe, Co, Ni, Cu,
Zn, Ga, Ge, Y, Zr, Nb, Mo, Tc, R
u, Rh, Pd, Ag, Cd, In, Sn, Sb, B
a, Hf, Ta, W, Re, Os, Ir, Pt, Au,
Hg, Tl, La, Ce, Pr, Nd, Pm, Sm, E
u, Gd, Tb, Dy, Ho, Er, Tm, Yb, L
It is composed of a simple substance such as u, Th, Pa, U, Np, and Am, or is composed of two or more kinds of elements such as oxide, chloride, fluoride, hydroxide, and bromide. The central metal is not limited to these elements. The charge generating substance having a phthalocyanine skeleton in the present invention means at least the general formula (14)
As long as it has a basic skeleton, it may have a multimeric structure such as a dimer or trimer, or may have a higher polymer structure. Further, the basic skeleton may have various substituents.

Among these various phthalocyanines, the oxotitanium phthalocyanine having TiO as the central metal and the metal-free phthalocyanine having H as the central metal are particularly preferable in terms of photoreceptor characteristics.

It is also known that these phthalocyanines have various crystal systems. For example, in the case of oxotitanium phthalocyanine, α, β, γ, m, y type, and in the case of copper phthalocyanine, α, β, It has a crystal polymorphism such as γ. Even in phthalocyanines having the same central metal, various characteristics change due to the change in crystal system. Among them, it has been reported that the characteristics of the photoconductor also change with such a crystal system change. (Journal of the Electrophotographic Society, Vol. 29, No. 4 (1990)) From this, each phthalocyanine has an optimum crystal system in terms of the characteristics of the photoconductor, and particularly in oxotitanium phthalocyanine,
A y-type crystal system is desirable.

Alternatively, the above general formulas (1), (9), (12) and (14)
In addition, inorganic materials such as selenium, selenium-tellurium, cadmium sulfide, cadmium sulfide-selenium, and α-silicon, and organic materials include, for example, CI Pigment Blue 25.
(Color Index CI21180), CI Pigment Red 41 (CI21200), CI Acid Red 52 (CI45100), CI Basic Red 3 (CI45210), an azo pigment having a carbazole skeleton (described in JP-A-53-95033),
Azo pigment having a dibenzothiophene skeleton
No. 21728), an azo pigment having an oxadiazole skeleton (described in JP-A No. 54-12742), and an azo pigment having a bisstilbene skeleton (JP-A No.
No. 4-17733), an azo pigment having a distyryloxadiazole skeleton (described in JP-A-54-2129), an azo pigment having a distyrylcarbazole skeleton (described in JP-A-54-14967). Azo pigments, such as CI Eye Bat Brown 5 (CI73
410), indigo-based pigments such as CI Eye Die (CI73030), Argos Scarlet B (manufactured by Bayer), Indence Scarlet R (manufactured by Bayer).
Pigments such as perylene pigments can also be used.
Further, two or more kinds of the charge generating substances described above may be mixed.

To prepare the photoreceptor shown in FIG. 2, one or more resins having a charge transporting ability or a solution obtained by dissolving the resin together with a binder or a low molecular weight charge transporting substance together with the binder are used. Fine particles of the charge generating substance 5 are dispersed in the dissolved solution, which is coated on the conductive support 1 and dried to form a photosensitive layer 2 '. On this photosensitive layer, a resin having a charge-transporting ability is used alone or in combination with a binder, or a low-molecular-weight charge-transporting substance is dissolved and dispersed in a core / shell graft copolymer together with a binder, coated, and dried. The protective layer 6 is provided. The thickness of the protective layer is 0.15 to 10 μm
Is preferred. The amount of resin in the protective layer 6 is 40 to 95.
% By weight, and the amount of core / shell graft copolymer is
20% by weight or less with respect to the resin, preferably 10
It is less than or equal to weight%. A protective layer consisting of a binder and a core / shell graft copolymer can also be used.

To prepare the photoreceptor shown in FIG. 3, the charge generating substance is vacuum-deposited on the conductive support 1, or the fine particles 5 of the charge generating substance are dissolved in a suitable solvent in which a binder is dissolved if necessary. The dispersion liquid dispersed in the above is applied and dried, and if necessary, surface finishing and film thickness adjustment are performed by a method such as buffing to form the charge generation layer 7, and one or more kinds thereof are formed on the charge generation layer 7. The charge transporting layer 4 which is prepared by dissolving and dispersing a resin having a charge transporting ability or a binder and a low molecular weight charge transporting substance together with a binder, and dissolving and dispersing the core / shell graft copolymer in the resin. Should be formed.

The charge generating substance used for forming the charge generating layer 7 is the same as that described for the photosensitive layer 2. The thickness of the charge generation layer 7 is 5 μm or less, preferably 2
the thickness of the charge transport layer 4 is 3 to 50 μm,
It is preferably 5 to 40 μm. When the charge generation layer 7 is of a type in which the fine particles 5 of the charge generation layer substance are dispersed in a binder, the proportion of the fine particles 5 of the charge generation substance in the charge generation layer 7 is preferably 10 to 100% by weight. Is about 50 to 100% by weight. Further, the amount of the resin having the charge transporting ability in the charge transporting layer 4 is 40 to 95% by weight, and the amount of the core / shell graft copolymer is 20% by weight or less based on the resin, preferably It is 10% by weight or less. As described above, a composition comprising a low molecular weight charge transporting substance and a binder may be used instead of the resin having the charge transporting ability. As the charge transporting substance, the compounds represented by the general formulas (15) to (17) are used. The compound represented by the formula (4) is used, and the production method and specific examples of the compound are described in JP-B-2-24864, JP-B-4-66023,
It is described in JP-A-53-27033.

Alternatively, the following compounds can be used in addition to the compounds represented by the general formulas (15) to (17). Oxazole derivative,
Oxadiazole derivatives (described in JP-A-52-139065 and JP-A-52-139066), imidazole derivatives, triphenylamine derivatives (JP-A-3-2)
85960), hydrazone derivatives (JP-A-55-154955, JP-A-55-156954, JP-A-55-154954).
5-52063, 56-81850, etc.), triphenylmethane derivatives (Japanese Patent Publication No. 51-1).
0983), anthracene derivatives (described in JP-A-51-94829), styryl derivatives (described in JP-A-56-29245 and JP-A-58-198043), and carbazole derivatives (described in JP-A-58-98043). 58-585
52), pyrene derivatives (JP-A-2-948)
No. 12)) and the like.

The method for producing the resin having the charge transporting ability represented by the general formula (18) and specific examples of the compound are described in JP-A-9-2.
No. 97419. In addition, the general formula (1
In addition to 8), the resins having the charge transporting ability described in the following documents can also be used.

Japanese Patent Application Laid-Open Nos. 51-73888 and 5
4-8527, JP-A-54-11737,
JP-A-56-150749, JP-A-57-784
No. 02, No. 63-285552, No. 64-1728, No. 64-13061, No. 64-19049, and No. 3-505.
55, JP-A-4-225014, JP-A-4
-230767, JP-A-5-232727, JP-A-5-310904, etc., JP-A-8-26
No. 9183, No. 9-71642, No. 9-104746, No. 9-272735, JP9806709, No. 9-235367, No. 9-87376, No. 9-87376. -110
976, JP-A-9-268226, JP9
702434, JP-A-9-221544, JP-A-9-227669, JP-A-9-157378, JP9702582, JP-A-9-302084, JP-A-9-302085, JP-A-9-328.
539, JP-A-11-5836, JP-A-1
1-71453, U.S. Pat. No. 4,801,517
Issue 4,806,443 Issue 4,806,444
No. 4, ibid. 4,937,165, ibid. 4,959,288
No. 5,035,532, No. 5,034,296
Nos. 5,080,989, JP-A-64-9
964, JP-A-3-221522, JP-A-2-304456, JP-A-4-11627, JP-A-4-175337, and JP-A-4-183.
71, JP-A-4-31404, and JP-A-4-31404.
No. 133065, etc.

To prepare the photoreceptor shown in FIG. 4, the charge generating substance is vacuum-deposited on the conductive support 1, or the fine particles 5 of the charge generating substance are dissolved in a suitable solvent in which a binder is dissolved if necessary. The dispersion liquid dispersed in the above is applied and dried, and if necessary, surface finishing and film thickness adjustment are performed by a method such as buffing to form the charge generation layer 7, and one or more kinds thereof are formed on the charge generation layer 7. The resin shown in FIG. 2 is used after forming a charge transport layer 4 by applying a solution of the resin having the charge transport ability alone or in combination with the binder or dissolving a low molecular weight charge transport material together with the binder and drying the solution. Layer 6 should be provided.

To prepare the photosensitive member shown in FIG. 5, one or two kinds of resins having a charge transporting ability are provided on the conductive support 1.
One or more or a combination of these and a binder, or a solution in which a low molecular weight charge transporting substance is dissolved with a binder is applied and dried to form a charge transporting layer 4, and then a charge generating substance is formed on the charge transporting layer. The charge generation layer 7 may be formed by coating and drying a dispersion liquid obtained by dispersing the fine particles of (1) together with the core / shell graft copolymer in a solvent in which a binder is dissolved if necessary by a method such as spray coating. The amount ratio of the charge generation layer or the charge transport layer is the same as that described in FIG.

To prepare the photosensitive member shown in FIG. 6, one or two kinds of resins having a charge transporting ability are provided on the conductive support 1.
One or more or a combination of these and a binder, or a solution in which a low molecular weight charge transporting substance is dissolved with a binder is applied and dried to form a charge transporting layer 4, and then a charge generating substance is formed on the charge transporting layer. 2 is provided by forming a charge generation layer 7 by coating and drying a dispersion liquid in which the fine particles of 1 are dispersed in a solvent in which a binder is dissolved by a method such as spray coating. Good.

To prepare the photoreceptor shown in FIG. 7, a core / shell graft copolymer and one or more resins having a charge transporting ability or a binder and a binder are provided on a conductive support 1. Or a low molecular charge transport material is dissolved and dispersed with a binder, and a sensitizing dye is added to the solution to form a solution, which is coated on a conductive support 1 and dried to form a photosensitive layer 2 "" The thickness of the photosensitive layer is 3 to
50 μm, preferably 5 to 40 μm is suitable. The amount of the resin or the low molecular weight charge transport material having charge transport ability in the photosensitive layer 2 """is 30 to 100% by weight, and
The amount of the sensitizing dye in the photosensitive layer 2 """is 0.1 to 5% by weight, preferably 0.5 to 3% by weight.

As a sensitization charge, brilliant green,
Triarylmethane dyes such as Victoria Blue B, Methyl Violet, Crystal Violet, Acid Violet 6B, Rhodamine B, Rhodamine 6G,
Rhodamine G Extra, Eosin S, Erythrosin,
Examples include xanthene dyes such as rose bengal and fluorescein, thiazine dyes such as methylene blue, and cyanine dyes such as cyanine.

In any of these photoconductor manufacturing processes, the conductive support 1 is made of a metal plate or metal foil such as aluminum, a plastic film deposited with a metal such as aluminum, or a paper subjected to a conductive treatment. Used. Further, 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 may be added to the binder, and examples of such a plasticizer include halogenated paraffin, dimethylnaphthalene and dibutyl phthalate.
Further, if necessary, additives such as an antioxidant, a light stabilizer, a heat stabilizer, and a lubricant can be added.

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 are polyamide, nitrocellulose, aluminum oxide, titanium oxide, etc., and the film thickness is 1 μm.
m or less is preferable. To perform copying using the photoconductor 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 photosensitive material of the present invention containing the core / shell graft copolymer thus obtained has high sensitivity,
In addition to the low friction and / or elastic function of the core layer, the shell layer has a compatibilizing function with the matrix resin, resulting in extremely excellent durability.

Next, the electrophotographic method and electrophotographic apparatus of the present invention will be described in detail with reference to the drawings. FIG. 8 is a schematic diagram for explaining the electrophotographic process cartridge and the electrophotographic apparatus of the present invention, and the following modified examples also belong to the category of the present invention.

In FIG. 8, the photoconductor of the present invention is used as the photoconductor 1. Although the photosensitive member 1 has a drum shape, it may have a sheet shape or an endless belt shape. As the charging charger 3, the pre-transfer charger 7, the transfer charger 10, the separation charger 11, and the pre-cleaning charger 13, known means such as a corotron, a scorotron, a solid state charger (solid state charger), and a charging roller are used. To be

Generally, the above-mentioned charger can be used as the transfer means, but it is effective to use a combination of a transfer charger and a separation charger as shown in FIG.

Light sources such as the image exposure section 5 and the static elimination lamp 2 are fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light emitting diodes (LEDs), semiconductor lasers (LDs), electroluminescence (E).
L) and other luminescent materials can be used in general. And
Various filters such as a sharp cut filter, a bandpass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can also be used to irradiate only light in a desired wavelength range. With such a light source and the like, the photosensitive member is irradiated with light by providing a process such as a transfer process using light irradiation, a charge eliminating process, a cleaning process, or a pre-exposure process in addition to the process shown in FIG.

The toner developed on the photoconductor 1 by the developing unit 6 is transferred to the transfer paper 9, but not all of it is transferred, and some toner remains on the photoconductor 1. Such toner is removed from the photoconductor by the fur brush 14 and the cleaning blade 15.
Cleaning may be performed only with a cleaning brush, and known cleaning brushes such as a fur brush and a magfur brush are used.

When the electrophotographic photosensitive member is positively (negatively) charged and imagewise exposed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. This is a negative (positive) polarity toner (electrolytic fine particles)
By developing with, a positive image can be obtained, and by developing with a toner of positive (negative) polarity, a negative image can be obtained. A known method is applied to the developing means, and a known method is used for the charge removing means.

FIG. 9 shows another example of the electrophotographic process according to the present invention. The photoconductor 21 is a photoconductor of the present invention, driven by drive rollers 22a and 22b, charged by a charging charger 23, image exposed by an image exposure source 24,
Development (not shown), transfer using the transfer charger 25,
Pre-cleaning exposure by the light source 26, cleaning by the cleaning brush 27, and static elimination by the static elimination light source 28 are repeated. In FIG. 10, the photoconductor 21
(Of course, in this case, the support is translucent) is irradiated with light for pre-cleaning exposure from the support side.

The electrophotographic process shown above illustrates the embodiment of the present invention, and of course other embodiments are possible. For example, in FIG. 9, the pre-cleaning exposure is carried out from the support side, but this may be carried out from the photosensitive layer side, or the image exposure and the irradiation of the destaticizing light may be carried out from the support side. On the other hand, in the light irradiation step, image exposure, pre-cleaning exposure, and static elimination exposure are shown. In addition, pre-transfer exposure, pre-exposure for image exposure, and other known light irradiation steps are provided to expose the photoreceptor to light. Irradiation can also be performed.

The image forming means as described above may be fixedly incorporated in a copying apparatus, a facsimile or a printer, but may be incorporated in these apparatuses in the form of a process cartridge. The process cartridge has a built-in photoconductor and additionally includes a charging unit, an exposing unit, a developing unit, a transferring unit, a cleaning unit, and a discharging unit.
It is one device (part). Although there are many shapes of process cartridges and the like, a general example is that shown in FIG. The photoconductor of the present invention is used as the photoconductor 16.

[0106]

EXAMPLES The present invention will be described below with reference to examples. <Preparation Example of Graft Copolymer Having Core / Shell Structure> 60.5 g of Metablen SX-005 (manufactured by Mitsubishi Rayon Co .; acrylic rubber is grafted on a composite rubber of organopolysiloxane and acrylic) is taken in 500 ml of ion-exchanged water.
Using a HOMO MIXER (MARKII), stirring operation for 15 minutes was performed 12 times. The conductivity of the 12th wash water is 1.75 μs / c
It was m. The obtained Metablen SX-005 was freeze-dried to obtain 58.2 g. In the following Examples 1 to 9, the metabrene SX-005 obtained by this operation is used.

Example 1 A polyamide resin (CM-800) dissolved in a mixed solvent of methanol / butanol on an aluminum plate was used.
(0: manufactured by Toray Industries, Inc.) The solution was applied with a doctor blade and naturally dried to form an intermediate layer of 0.3 μm. A bisazo compound represented by the following formula (10) as a charge generating substance was pulverized with a ball mill in a mixed solvent of cyclohexanone and 2-butanone, and the obtained dispersion was coated with a doctor blade and naturally dried. A 0.5 μm charge generation layer was formed.

[0108]

[Chemical 42]

Next, the METABLEN SX-005 0.
012 g and 2.375 g of a polymer charge transporting substance (weight average molecular weight = 18000) of the following structural formula (19) were taken in 15.96 ml of tetrahydrofuran and dispersed by ball milling for 3 hours, and this dispersion was placed on the charge generation layer. It was coated with a doctor blade, naturally dried, and then dried at 120 ° C. for 20 minutes to form a charge transport layer having a thickness of 20 μm, to prepare a photoconductor.

[0110]

[Chemical 43] Random copolymer of k = 0.42 and j = 0.58

About the photoconductor thus produced, a commercially available electrostatic copying paper test apparatus [SP428 manufactured by Kawaguchi Electric Co., Ltd.]
Mold] to perform corona discharge of −6 KV in the dark for 20 seconds to charge the surface, and then measure the surface potential V _m (V) of the photoconductor, and leave it in the dark for 20 seconds.
₀ (V) was measured. Next, a tungsten lamp light is irradiated so that the illuminance on the surface of the photoconductor becomes 5.3 lux, and the time (second) until V ₀ becomes 1/2 is obtained, and the exposure amount E _1/2 (lux -Sec) was calculated. The results are shown in Table 2.

<Examples 2 and 3> A photoconductor was prepared in the same manner as in Example 1 except that the composition ratio (parts by weight) of methabrene SX-005 and the polymer charge transport material in Example 1 was changed as shown in Table 1. Then, the electrical characteristics were evaluated. The results are shown in Table 1.

[0113]

[Table 1]

Example 4 An intermediate layer and a charge generation layer were respectively formed on an aluminum plate in the same manner as in Example 1, and 2.5 g of the polymer charge transport material used in Example 1 was added to tetrahydrofuran 15 The solution dissolved in 0.96 ml was applied with a doctor blade and air-dried to form a 10 μm polymer charge transport layer. Next, the weight composition ratio of the metabrene SX-005 and the polymer charge transport material used in Example 1 was 5:
A tetrahydrofuran dispersion of 95 was coated on the polymer charge transport layer with a doctor blade, air-dried, and then dried at 120 ° C. for 20 minutes to form a charge transport layer having a thickness of 10 μm, thereby preparing a photoreceptor. . The electrical characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.

<Example 5> An intermediate layer and a charge generation layer were formed on an aluminum plate in the same manner as in Example 1, and a charge transport layer coating solution having the following composition was dispersed thereon by ball milling. Apply with a doctor blade, air dry, 20 μm
A photosensitive member was prepared by forming the molecule-dispersed charge transport layer of (1) (parts represent parts by weight). Charge-transporting substance of the following structural formula (20) 8.4 parts Polycarbonate resin 9.3 parts (Panlite TS2050, manufactured by Teijin Chemicals Ltd.) Metablen SX-005 0.36 parts Dichloromethane 100 parts

[0116]

[Chemical 44]

The electrical characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.

Example 6 A photoconductor was prepared in the same manner as in Example 1 except that the bisazo compound as the charge generating substance was replaced with the trisazo compound represented by the following formula (8), and the electrical characteristics were evaluated. The results are shown in Table 2.

[0119]

[Chemical formula 45]

Example 7 A photoconductor was prepared in the same manner as in Example 1 except that the bisazo compound was replaced with the oxotitanium phthalocyanine pigment represented by the following formula (21) as the charge generating substance, and the electrical characteristics were evaluated. It was The results are shown in Table 2.
Shown in.

[0121]

[Chemical formula 46]

<Embodiment 8> Embodiment 1 as a charge generating substance
A photoconductor was prepared in the same manner as in Example 1 except that the bisazo compound used in Example 1 was replaced with the bisazo compound represented by the following formula (11), and the electrical characteristics were evaluated. The results are shown in Table 2.

[0123]

[Chemical 47]

Example 9 A photoconductor was prepared in the same manner as in Example 1 except that the bisazo compound used as the charge generating substance was replaced with the bisazo compound represented by the following formula (13), and the electrical characteristics were evaluated. It was The results are shown in Table 2.

[0125]

[Chemical 48]

Further, after charging the above photoconductor using a commercially available electrophotographic copying machine, light irradiation is conducted through the original image to form an electrostatic latent image, and the latent image is developed with a dry developer.
The obtained image (toner image) is electrostatically transferred onto plain paper,
When fixed, a clear transfer image was obtained. Even when a wet type developer was used as the developer, a clear transfer image was similarly obtained.

Abrasion Amount Evaluation Test 1 A Taber abrasion test was conducted using the photoreceptor obtained in Example 1 as a sample. Industrial standard
According to JIS K 7204 (1995), a Taber abrasion tester (manufactured by Toyo Seiki Co., Ltd.) was used to carry out an abrasion test of 3000 revolutions at a load of 1 kg using a CS-5 abrasion wheel, and the abrasion loss after 3000 revolutions is shown in Table 2. Indicated.

Wear amount evaluation test 2 to 9 Wear amount evaluation test 1
A Taber abrasion test was conducted in the same manner as in the abrasion amount evaluation test 1 except that the photoreceptors used in Example 2 were replaced with the photoreceptors obtained in Examples 2 to 9. The results are shown in Table 2.

<Comparative Example 1> As a comparative example, a photoreceptor was prepared in the same manner as in Example 1 except that the graft copolymer (SX-005) was not used, and a Taber abrasion test was conducted. The results are shown in Table 2.

Comparative Examples 2 and 3 The metabrene SX-005 in Example 1 was prepared by using polysiloxane fine particles (trefill R-902A manufactured by Toray Silicon Co., Ltd.) (Comparative Example 2) or crosslinked polystyrene fine particles (SX8742 (D) -05).
A photoconductor was prepared in the same manner as in Example 1 except that each was replaced with (Compound by Japan Synthetic Rubber Co., Ltd.) (Comparative Example 3), and a Taber abrasion test was conducted in the same manner as in Example 7. The results are shown in Table 2.

<Comparative Example 4> Graft copolymer (SX-0
A photoconductor was prepared in the same manner as in Example 5 except that 05) was not used, and a Taber abrasion test was conducted. The results are shown in Table 2.

[0132]

[Table 2]

As is clear from the evaluation results of the electrophotographic characteristics and wear amount of Examples 1 to 9 shown in Table 2, all the photoreceptors according to the present invention have high sensitivity and excellent wear resistance. .

[134] Also, in the above example, metabrene S
An example using X-005 is shown, but Metabrene SP, which is a graft copolymer having the same core / shell structure, is also shown.
It was confirmed that even when K200 (core: siloxane / acryl, shell: styrene / acrylonitrile) and methabrene SX2 (core: siloxane / acryl, shell: styrene) were used, the same effect as above was obtained.

[0135]

The photosensitive material of the present invention contains a graft copolymer having at least a core / shell structure as an active ingredient in the photosensitive layer. This graft copolymer is a copolymer having a low friction coefficient and / or elasticity in the core portion and a polymer having a good compatibility with the matrix resin of the photosensitive layer in the shell portion, so that the photoreceptor is repeatedly used. High durability can be maintained because the function of the core portion continues even when time passes.

[Brief description of drawings]

FIG. 1 is a sectional view showing a layer structure of an electrophotographic photoreceptor according to the present invention.

FIG. 2 is a sectional view showing a layer structure of an electrophotographic photoreceptor according to the present invention.

FIG. 3 is a cross-sectional view showing the layer structure of an electrophotographic photoreceptor according to the present invention.

FIG. 4 is a sectional view showing the layer structure of an electrophotographic photoreceptor according to the present invention.

FIG. 5 is a sectional view showing a layer structure of an electrophotographic photoreceptor according to the present invention.

FIG. 6 is a cross-sectional view showing the layer structure of an electrophotographic photoreceptor according to the present invention.

FIG. 7 is a sectional view showing the layer structure of an electrophotographic photoreceptor according to the present invention.

FIG. 8 is a schematic diagram for explaining an electrophotographic process cartridge and an electrophotographic apparatus of the present invention.

FIG. 9 is a schematic view showing another example of the electrophotographic process according to the present invention.

FIG. 10 is a schematic view showing another example of the process cartridge according to the present invention.

[Explanation of symbols]

(About FIGS. 1 to 7) 1 Conductive support 2, 2 ', 2 ", 2"', 2 "", 2 ""', 2 """
Photosensitive Layer 3 Graft Copolymer 4 Having Core / Shell Structure 4 Charge Transport Layer or Charge Transport Medium 5 Charge Generating Material 6 Protective Layer 7 Charge Generating Layer (Regarding FIGS. 8 to 10) 1, 16 and 21 Photoreceptor 2 Static Elimination Lamp 3 , 17, 23 Charging charger 5, 19 Image exposure unit 6 Developing unit 7, 25 Pre-transfer charger 8 Registration roller 9 Transfer paper 10 Transfer charger 11 Separation charger 12 Separation claw 13 Pre-cleaning charger 14 Fur brush 15 Cleaning blade 18, 27 Cleaning Brush 20 Developing roller 22a Driving roller 22b Driving roller 24 Image exposure source 26 Pre-cleaning exposure 28 Static elimination light source

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 5/06 360 G03G 5/06 360C 371 371 5/07 103 5/07 103 (72) Inventor Hajime Nagai Kiyoshi 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd. (72) Inventor Shinichi Kawamura 1-3-6 Nakamagome, Ota-ku, Tokyo F-term within Ricoh Co., Ltd. (reference) 2H068 AA14 AA19 AA20 BA12 BA13 BA38 BA39 BA44 BA45 BA51 BB61

Claims (14)

[Claims] 1. An electrophotographic photoreceptor comprising at least a charge generating material and a charge transporting material on a conductive support, the outermost layer of which contains a graft copolymer having a core / shell structure, Is a trisazo compound represented by the following general formula (1), an electrophotographic photoreceptor. [Chemical 1] (However, in the general formula 1, R ¹ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or a cyano group, and
Represents a coupler residue. ) 2. The coupler residue A in the trisazo compound of the general formula (1) is selected from residues represented by the following general formulas (2) to (7). The electrophotographic photoreceptor according to 1. [Chemical 2] [However, in the above formula, X ¹ , Y ¹ and Z respectively represent the following. ^{X 1: -OH, -N (R} 2) (R 3) or, -N
HSO ₂ -R ^4. (R ² and R ³ represent a hydrogen atom, an acyl group or a substituted or unsubstituted alkyl group, and R ⁴ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group.) Y ¹ : hydrogen atom A halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group,
Carboxy group, a sulfonic group, benzimidazolyl group, a substituted or unsubstituted sulfamoyl group, a substituted or unsubstituted allophanoyl group or ^{-CON (R 5) (Y 2} ). {R ⁵ represents a hydrogen atom, an alkyl group or a substituted product thereof, a phenyl group or a substituted product thereof, and Y ²
The hydrocarbon ring group or a substitution product thereof, a heterocyclic group or a substitution product thereof, or ^{-N = C (R 6) (} R 7) ( where, R ⁶
Is a hydrocarbon ring group or a substituted product thereof, a heterocyclic group or a substituted product thereof, a styryl group or a substituted product thereof, R ⁷ represents a hydrogen atom, an alkyl group or a substituted product thereof, a phenyl group or a substituted product thereof, or R 6 And R7
May form a ring with the carbon atom bonded to them). } Z: Hydrocarbon ring group or a substituted body thereof, or heterocyclic group or a substituted body thereof. ] [Chemical 3] (In the above formula, R ⁸ represents a substituted or unsubstituted hydrocarbon group.) (In the above formula, R ⁹ represents a substituted or unsubstituted hydrocarbon group.) (In the above formula, R ¹⁰ represents an alkyl group, a carbamoyl group, a carboxyl group or an ester thereof, and Ar ¹ represents a substituted or unsubstituted aromatic hydrocarbon group.) (In the above formula, X ² represents a divalent group of an aromatic hydrocarbon or a divalent group of a heterocyclic ring.) (In the above formula, X ² represents an aromatic hydrocarbon divalent group or a heterocyclic divalent group.) 3. The electrophotographic photoreceptor according to claim 1, wherein the trisazo compound is a compound represented by the following formula (8). [Chemical 8] 4. An electrophotographic photoreceptor comprising at least a charge generating material and a charge transporting material on a conductive support, the outermost layer of which contains a graft copolymer having a core / shell structure, and the charge generating material. Is a bisazo compound represented by the following general formula (9). [Chemical 9] (In the formula, R ¹¹ and R ¹² are a hydrogen atom, a halogen atom,
It represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a cyano group or a nitro group and may be the same or different. B and C represent a coupler residue and may be the same or different. Specifically, it is defined in the same manner as the coupler residue A shown in claim 2. ) 5. The bisazo compound represented by the following formula (10) is used as the bisazo compound.
The electrophotographic photoreceptor according to item 1. [Chemical 10] 6. The bisazo compound represented by the following formula (11), wherein the bisazo compound is a bisazo compound.
The electrophotographic photoreceptor according to item 1. [Chemical 11] 7. An electrophotographic photoreceptor containing at least a charge generating material and a charge transporting material on a conductive support, the outermost layer of which contains a graft copolymer having a core / shell structure, and the charge generating material. Is a bisazo compound represented by the following general formula (12). [Chemical 12] (In the formula, D and E represent a coupler residue and may be the same or different. Specifically, they are defined in the same manner as the coupler residue A shown in claim 2.) 8. The bisazo compound represented by the following formula (13), wherein the bisazo compound is a bisazo compound.
The electrophotographic photoreceptor according to item 1. [Chemical 13] 9. An electrophotographic photoreceptor comprising at least a charge generating material and a charge transporting material on a conductive support, wherein the outermost layer contains a graft copolymer having a core / shell structure, Is a phthalocyanine compound represented by the following general formula (14). [Chemical 14] [In the formula, M represents a metal or, in the absence of a metal, represents two hydrogen atoms. ] 10. An electrophotographic photoreceptor comprising at least a charge generating material and a charge transporting material on a conductive support,
The outermost layer contains a graft copolymer having a core / shell structure, and the charge generating material is the above general formula (1),
An electrophotographic photoreceptor, which is a mixture of two or more compounds represented by (9), (12) and (14). 11. An electrophotographic photoreceptor comprising at least a charge generation material and a charge transport material on a conductive support,
The outermost layer contains a graft copolymer having a core / shell structure, and the charge transport material is an α-phenylstilbene derivative represented by the following general formula (15). . [Chemical 15] (In the formula, n is an integer of 0 or 1, Ar ⁵ and Ar ⁶ are a substituted or unsubstituted aryl group [however, the case of an unsubstituted phenyl group at the same time is excluded], or a group which forms a ring in cooperation with each other. Wherein Ar ⁷ represents a substituted or unsubstituted aryl group, R ¹⁶ , R ¹⁷ and R ¹⁸ represent a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, and the above aryl group and The substituent of the arylene group is
It is an alkoxy group, a phenoxy group, an alkyl group, a hydroxy group, a halogen atom, a cyano group, or a nitro group. ) 12. The electrophotographic photoreceptor according to claim 11, wherein the α-phenylstilbene derivative is an α-phenylstilbene derivative represented by the following general formula (16). [Chemical 16] (In the formula, R ¹⁹ represents a hydrogen atom, an alkyl group, an alkoxy group,
Alternatively, it represents a halogen atom. ) 13. An electrophotographic photoreceptor comprising at least a charge generating material and a charge transporting material on a conductive support,
A photoreceptor for electrophotography, wherein the outermost layer contains a graft copolymer having a core / shell structure, and the charge transport material is a benzidine compound represented by the following general formula (17). [Chemical 17] (In the formula, R ²⁰ represents a lower alkyl group, a lower alkoxy group or a halogen atom, R ²¹ and R ²² may be the same or different, and represent a hydrogen atom, a lower alkyl group, a lower alkoxy group or a halogen atom, h, l, and m represent the integer of 0-4.) 14. An electrophotographic photoreceptor comprising at least a charge generating material and a charge transport material on a conductive support,
The outermost layer contains a graft copolymer having a core / shell structure, and the charge-transporting material has the following general formula (1
An electrophotographic photoreceptor, which is a charge-transporting polymer having a triarylamine structure represented by 8). [Chemical 18] [In the formula, Ar ¹ , Ar ² and Ar ³ represent a substituted or unsubstituted arylene group. R ¹ and R ² represent the same or different acyl groups, substituted or unsubstituted alkyl groups, and substituted or unsubstituted aryl groups. k is an integer of 5 to 5000, j
Is an integer of 5 to 5000, and 0 <k / (k + j) ≦ 1. X is a substituted or unsubstituted aliphatic divalent group, a substituted or unsubstituted cycloaliphatic divalent group, a substituted or unsubstituted aromatic divalent group, or a divalent group formed by linking these, or Show what is represented. ] [Chemical 19] (Here, R ³ , R ⁴ , R ⁵ , and R ⁶ are independently a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a halogen atom. And a and b are each independently 0. Is an integer of 4 to 4, c and d are each independently an integer of 0 to 3, and when a plurality of R ³ , R ⁴ , R ⁵ and R ⁶ are present, they may be the same or different. Y is a single bond, a linear alkylene group having 2 to 12 carbon atoms, a substituted or unsubstituted branched alkylene group having 3 to 12 carbon atoms, or one or more alkylene groups having 1 to 10 carbon atoms. And a divalent group consisting of one or more oxygen and sulfur atoms, -O-, -S-, -S
O-, -SO _2- , -CO-, -COO-, or Z ¹ and Z ² are each a substituted or unsubstituted aliphatic
Represents a divalent group or a substituted or unsubstituted arylene group, R
⁷ , R ¹⁴ represents a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ ,
R ¹² and R ¹³ each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, or a substituted or unsubstituted aryl group. R ⁸ and R ⁹ may combine to form a carbon ring having 5 to 12 carbon atoms, R ¹⁵ and R ¹⁶ represent a single bond or an alkylene group having 1 to 4 carbon atoms, and R ¹⁷ and R ¹⁸ Each independently represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, e and g are integers from 0 to 4, f is 1 or 2, h
Represents an integer of 0 to 20, and i represents an integer of 0 to 2000. )