Electrophotographic photoconductor, and process cartridge and electrophotographic apparatus using the same

• US 6,939,651 B2
• Filed: 06/21/2002
• Issued: 09/06/2005
• Est. Priority Date: 06/21/2001
• Status: Expired due to Fees

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Kawamura, Shinichi, Suzuki, Yasuo, Sasaki, Masaomi, Tamoto, Nozomu, Nagai, Kazukiyo, Li, Hongguo, Tanaka, Kawori
• Primary Examiner(s): Dote, Janis L.
• Application Number:
  US10/175,799
• Publication Number:
  US 20030059695A1
• Time in Patent Office: 1,173 Days
• Field of Search: 430/58.2, 430/58.7, 430/66, 430/67, 430/56, 399/116, 399/159
• US Class Current: 430/66
• CPC Class Codes: G03G 5/0546 Polymers comprising at least one carboxyl radical, e.g. polyacrylic acid, polycrotonic acid, polymaleic acid; Derivatives thereof, e.g. their esters, salts, anhydrides, nitriles, amides
• CPC Class Codes: G03G 5/0578 Polycondensates comprising silicon atoms in the main chain
• CPC Class Codes: G03G 5/0596 Macromolecular compounds characterised by their physical properties
• CPC Class Codes: G03G 5/075 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds G03G5/078 takes precedence

Abstract

An electrophotographic photoconductor comprising at least an electroconductive support and a photoconductive layer which is formed on said electroconductive support, the outermost layer of the photoconductor contains particles comprising a polyorganosiloxane-containing phase which contains polyorganosiloxane and an organic polymer-containing phase which contains organic polymer without silicon and has a polyorganosiloxane content which is less than the polyorganosiloxane-containing phase, each phase being exposed at the top surface of the photoconductor.

Claims

1. An electrophotographic photoconductor comprising:

an electroconductive support and a photoconductive layer thereon; and

an outermost layer of the photoconductive layer comprising particles;

wherein a surface of the particles comprises;

a) a poly organosiloxane-containing phase which contains polyorganosiloxane; and

b) an organic polymer-containing phase which contains organic polymer without silicone or having polyorganosiloxane content less than the polyorganosiloxane-containing phase.

2. An electrophotographic photoconductor according to claim 1, wherein a ratio of the polyorganosiloxane to the organic polymer (mass ratio of the polyorganosiloxane/organic polymer) is in a range of 30:

70 to 90;

10.

3. An electrophotographic photoconductor according to claim 1, wherein the particles have a cross sectional shape of circle or oval and are dispersed in the outermost surface layer of the photoconductive layer.

4. An electrophotographic photoconductor according to claim 1, wherein the organic polymer comprises one member selected from the group consisting of:

1) a copolymer of a (meth) acrylic acid ester; and

2) a copolymer of a monomer copolymerizable with the (meth) acrylic acid ester.

5. The electrophotographic photoconductor according to claim 1, wherein the photoconductive layer comprises an inorganic filler.

6. The electrophotographic photoconductor according to claim 1, wherein the photoconductive layer comprises a high molecular charge transport material.

7. The electrophotographic photoconductor according to claim 6, wherein the high molecular charge transport material comprises a unit represented by the following formula (A) and a unit represented by the following formula (B), in which the compositional ratio (k) of the unit represented by the formula (A) and the compositional ratio (j) of the unit represented by the formula (B) satisfy 0<

k/(k+j)≦

1;

in the formula (A);

R₁₆ is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group;

Ar₁₁, Ar₁₂ and Ar₁₃ are a substituted or unsubstituted arylene group; and

R₁₄ and R₁₅ are a substituted or unsubstituted aryl group;

in the formula (B);

X is a substituted or unsubstituted divalent aliphatic hydrocarbon group having 2 to 20 carbon atoms;

a substituted or unsubstituted divalent cycloaliphatic hydrocarbon group;

a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 20 carbon atoms;

a divalent group combined with the forgoing groups;

or a divalent group expressed by at least any one compound represented by the formulae (a) to (c);

in the formulae (a) to (c);

R₁₀₁, R₁₀₂, R₁₀₃ and R₁₀₄ are a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group, provided that R₁₀₁, R₁₀₂, R₁₀₃ and R₁₀₄ may be identical or may be different when they are each present in plurality;

o and p are independently an integer of 0 to 4;

q and r are independently an integer of 0 to 3; and

Y is a single bond, a straight-chained alkylene group having 2 to 12 carbon atoms, a branched substituted or unsubstituted alkylene group having 3 to 12 carbon atoms, at least one alkylene group having 1 to 10 carbon atoms, a divalent group containing at least one oxygen atom and sulfur atom, —

O—

, —

S—

, —

SO—

, —

SO₂—

, —

CO—

, —

COO—

or a divalent group represented by at least any one of the following formulae (d) to (m);

in the formulae (d) to (m)

Z₁ and Z₂ are a substituted or unsubstituted divalent aliphatic hydrocarbon group having 2 to 20 carbon atoms or a substituted or unsubstituted arylene group, provided that Z₁ and Z₂ may be identical or different;

R₁₀₅ is a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group;

R₁₀₆ and R₁₀₇ are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxyl group having 1 to 6, carbon atoms or a substituted or unsubstituted aryl group, or R₁₀₆ and R₁₀₇ may bond together to form a cyclic carbon having 5 to 12 carbon atoms;

R₁₀₈, R₁₀₉, R₁₁₀ and R₁₁₁ are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group;

R₁₁₂ is a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group;

R₁₁₃ and R₁₁₄ are a single bond or an alkylene group having 1 to 4 carbon atoms;

R₁₁₅ and R₁₁₆ are independently, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group;

s is an integer of 0 to 4;

t is an integer of 1 or 2;

u is an integer of 0 to 4;

v is an integer of 0 to 20; and

w is an integer of 0 to 2000.

8. The electrophotographic photoconductor according to claim 6, wherein the high molecular charge transport material comprises a unit represented by the following formula (C) and a unit represented by the following formula (B), in which the compositional ratio (k) of the unit represented by the formula (C) and the compositional ratio (j) (of the unit represented by the formula (B) satisfy 0<

k/(k+j)≦

1;

in the formula (B);

X is a substituted or unsubstituted divalent aliphatic hydrocarbon group having 2 to 20 carbon atoms;

a substituted or unsubstituted divalent cycloaliphatic hydrocarbon group;

a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 20 carbon atoms;

a divalent group combined with the forgoing groups;

or at least any one represented by the formulae (a) to (c),

in the formulae (a) to (c);

R₁₀₁, R₁₀₂, R₁₀₃ and R₁₀₄ are a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group, provided that R₁₀₁, R₁₀₂, R₁₀₃ and R₁₀₄ may be identical or different when they are each present in plurality;

o and p are independently an integer of 0 to 4;

q and r are independently an integer of 0 to 3; and

Y is a single bond, a straight-chained alkylene group having 2 to 12 carbon atoms, a branched substituted or unsubstituted alkylene group having 3 to 12 carbon atoms, at least one alkylene group having 1 to 10 carbon atoms, a divalent group containing at least one oxygen atom and sulfur atom, —

O—

, —

S—

, —

SO—

, —

SO₂—

, —

CO—

, —

COO—

or a divalent group represented by at least any one of the following formulae (d) to (m);

in the formulae (d) to (m),

Z₁ and Z₂ are a substituted or unsubstituted divalent aliphatic hydrocarbon group having 2 to 20 carbon atoms or a substituted or unsubstituted arylene group, provided that Z₁ and Z₂ may be identical or different;

R₁₀₅ is a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group;

R₁₀₆ and R₁₀₇ are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group, or R₁₀₆ and R₁₀₇ may bond together to form a cyclic carbon having 5 to 12 carbon atoms;

R₁₀₈, R₁₀₉, R₁₁₀ and R₁₁₁ are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carton atoms, a substituted or unsubstituted alkoxyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group;

R₁₁₂ is a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group;

R₁₁₃ and R₁₁₄ are a single bond or an alkylene group having 1 to 4 carbon atoms;

R₁₁₅ and R₁₁₆ are independently, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group;

s is an integer of 0 to 4;

t is an integer of 1 or 2;

u is an integer of 0 to 4;

v is an integer of 0 to 20; and

w is an integer of 0 to 2000;

in the formula (C);

R₁₉ and R₂₀ are a straight chain or branched alkylene group, Y₄ is a substituted or unsubstituted arylene group or —

Ar₂₅—

Y₅—

Ar₂₅—

, in which Ar₁₄, Ar₁₅ and Ar₂₅ are a substituted or unsubstituted arylene group and Y₅ is O, S or a substituted or unsubstituted arylene group, e is 0 or 1, Ar₁₁ and Ar₁₂ are a substituted or unsubstituted arylene group, and R₁₄ and R₁₅ are a substituted or unsubstituted aryl group.

9. An electrophotographic photoconductor comprising:

an electroconductive support and a photoconductive layer thereon;

wherein an outermost layer of the photoconductor comprises an acryl-modified polyorganosiloxane comprising

a) main chain of a polyorganosiloxane; and

b) a graft chain of an acryl polymer without containing silicon;

wherein the acryl-modified polyorganosiloxane is prepared by emulsion graft copolymerizing of a polyorganosiloxane compound represented by the following formula (I) and a (meth)acrylic acid ester represented by the following formula (II) or a mixture of the (meth)acrylic acid ester and a monomer copolymerizable with the (meth)acrylic acid ester via emulsion graft copolymerization;

Formula (I)

in the formula (I),

each of R₁, R₂ and R₃ is a hydrocarbon group having 1 to 20 carbon atoms and R₁, R₂ and R₃ may be identical or different, or be halogenated;

Y is an organic group containing either a radical reactive group or SH group or both of them;

each of Z₁ and Z₂ is a hydrogen atom, lower alkyl group or one represented by the following formula (n), and Z₁ and Z₂ may be identical or different;

m is a plus integer of 10,000 or less; and

n is an integer of 1 or more;

in the formula (n)

each of R₄ and R₅ is a hydrocarbon group or a halogenated hydrocarbon group having 1 to 20 carbon atoms and R₄ and R₅ may be identical or different; and

R₆ is a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group, an organic group containing either a radical reactive group or SH group or both of them;

in the formula (II);

R₇ is a hydrogen atom or a methyl group; and

R₈ is at least any one member selected from the group consisting of an alkyl group, alkoxy-substituted alkyl group, cyclo alkyl group and aryl group.

10. The electrophotographic photoconductor according to claim 9, wherein the acryl-modified polyorganosiloxane is cleaned with alcohol.

11. The electrophotographic photoconductor according to claim 9, wherein a sodium content to the acryl-modified polyorganosiloxane in the outermost surface layer of the photoconductive layer is 500 ppm or less.

12. The electrophotographic photoconductor according to claim 9, wherein a content of sulfur containing ion to the acryl-modified polyorganosiloxane in the outermost surface layer of the photoconductive layer is 800 ppm or less.

13. The electrophotographic photoconductor according to claim 9, wherein the acryl-modified polyorganosiloxane is dispersed as a particle phase and the average particle diameter of the acryl-modified polyorganosiloxane particles (volume average particle diameter(D₅₀)) is in the range of 0.1 to 0.6 μ

m.

14. The electrophotographic photoconductor according to claim 9, wherein the acryl-modified polyorganosiloxane is subjected to a high pressure with at least one of a solvent and a binder and crushed and dispersed by liquid impact under elevated pressure, so as to be dispersed as a particle phase and the average particle diameter of the acryl-modified polyorganosiloxane particles (volume average particle diameter(D₅₀)) is in the range of 0.1 to 0.6 μ

m.

15. The electrophotographic photoconductor according to claim 9, wherein the photoconductive layer comprises an inorganic filler.

16. The electrophotographic photoconductor according to claim 9, wherein the photoconductive layer comprises a high molecular charge transport material.

17. The electrophotographic photoconductor according to claim 16, wherein the high molecular charge transport material comprises a unit represented by the following formula (A) and a unit represented by the following formula (B), in which the compositional ratio (k) of the unit represented by the formula (A) and the compositional ratio (j) of the unit represented by the formula (B) satisfy 0<

k/(k+j)≦

1;

in the formula (A);

R₁₆ is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group;

Ar₁₁, Ar₁₂ and Ar₁₃ are a substituted or unsubstituted arylene group; and

R₁₄ and R₁₅ are a substituted or unsubstituted aryl group;

in the formula (B);

X is a substituted or unsubstituted divalent aliphatic hydrocarbon group having 2 to 20 carbon atoms;

a substituted or unsubstituted divalent cycloaliphatic hydrocarbon group;

a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 20 carbon atoms;

a divalent group combined with the forgoing groups;

or at least any one represented by the formulae (a) to (c);

in the formulae (a) to (c);

R₁₀₁, R₁₀₂, R₁₀₃ and R₁₀₄ are a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group, provided that R₁₀₁,

R₁₀₂, R₁₀₃ and R₁₀₄ may be identical or different when they are each present in plurality;

o and p are independently an integer or 0 to 4;

q and r are independently an integer of 0 to 3; and

Y is a single bond, a straight-chained alkylene group having 2 to 12 carbon atoms, a branched substituted or unsubstituted alkylene group having 3 to 12 carbon atoms, at least one alkylene group having 1 to 10 carbon atoms, a divalent group containing at least one oxygen atom and sulfur atom, —

O—

, —

S—

, —

SO—

, —

SO₂—

, —

CO—

, —

COO—

or a divalent group represented by at least any one of the following formulae (d) to (m);

in the formulae (d) to (m);

Z₁ and Z₂ are a substituted or unsubstituted divalent aliphatic hydrocarbon group having 2 to 20 carbon atoms or a substituted or unsubstituted arylene group, provided that Z₁ and Z₂ may be identical or different;

R₁₀₅ is a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group;

R₁₀₆ and R₁₀₇ are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group, or R₁₀₆ and R₁₀₇ may bond together to form a cyclic carbon having 5 to 12 carbon atoms;

R₁₀₈, R₁₀₉, R₁₁₀ and R₁₁₁ are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carton atoms, a substituted or unsubstituted alkoxyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group;

R₁₁₂ is a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group;

R₁₁₃ and R₁₁₄ are a single bond or an alkylene group having 1 to 4 carbon atoms;

R₁₁₅ and R₁₁₆ are independently, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group;

s is an integer of 0 to 4;

t is an integer of 1 or 2;

u is an integer of 0 to 4;

v is an integer of 0 to 20; and

w is an integer of 0 to 2000.

18. The electrophotographic photoconductor according to claim 16, wherein the high molecular charge transport material comprises a unit represented by the following formula (C) and a unit represented by the following formula (B), in which the compositional ratio (k) of the unit represented by the formula (C) and the compositional ratio (j) of the unit represented by the formula (B) satisfy 0<

k/(k+j)≦

1;

in the formula (B);

X is a substituted or unsubstituted divalent aliphatic hydrocarbon group having 2 to 20 carbon atoms;

a substituted or unsubstituted divalent cycloaliphatic hydrocarbon group;

a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 20 carbon atoms;

a divalent group combined with the forgoing groups;

or at least any one represented by the formulae (a) to (c);

in the formulae (a) to (c);

R₁₀₁, R₁₀₂, R₁₀₃ and R₁₀₄ are a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group, provided that R₁₀₁, R₁₀₂, R₁₀₃ and R₁₀₄ may be identical or different when they are each present in plurality;

o and p are independently an integer of 0 to 4;

q and r are independently an integer of 0 to 3; and

Y is a single bond, a straight-chained alkylene group having 2 to 12 carbon atoms, a branched substituted or unsubstituted alkylene group having 3 to 12 carbon atoms, at least one alkylene group having 1 to 10 carbon atoms, a divalent group containing at least one oxygen atom and sulfur atom, —

O—

, —

S—

, —

SO—

, —

SO₂—

, —

CO—

, —

COO—

or a divalent group represented by at least any one of the following formulae (d) to (m);

in the formulae (d) to (m);

Z₁ and Z₂ are a substituted or unsubstituted divalent aliphatic hydrocarbon group having 2 to 20 carbon atoms or a substituted or unsubstituted arylene group, provided that Z₁ and Z₂ may be identical or different;

R₁₀₅ is a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group;

R₁₀₆ and R₁₀₇ are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group, or R₁₀₆ and R₁₀₇ may bond together to form a cyclic carbon having 5 to 12 carbon atoms;

R₁₀₈, R₁₀₉, R₁₁₀ and R₁₁₁ are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group;

R₁₁₂ is a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group;

R₁₁₃ and R₁₁₄ are a single bond or an alkylene group having 1 to 4 carbon atoms;

R₁₁₅ and R₁₁₆ are independently, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group;

s is an integer of 0 to 4;

t is an integer of 1 or 2;

u is an integer of 0 to 4;

v is an integer of 0 to 20; and

w is an integer of 0 to 2000;

in the formula (C);

R₁₉ and R₂₀ are a straight-chained or branched alkylene group, Y₄ is a substituted or unsubstituted arylene group or —

Ar₂₅—

Y₅—

Ar₂₅—

, in which Ar₁₄, Ar₁₅ and Ar₂₅ are a substituted or unsubstituted arylene group and Y₅ is O, S or a substituted or unsubstituted arylene group, e is 0 or 1, Ar₁₁ and Ar₁₂ are a substituted or unsubstituted arylene group, and R₁₄ and R₁₅ are a substituted or unsubstituted aryl group.

19. A process cartridge comprising an electrophotographic photoconductor which comprises:

an electroconductive support and a photoconductive layer thereon; and

an outermost layer of the photoconductive layer comprising particles;

wherein a surface of the particles comprises;

a) a polyorganosiloxane-containing phase which contains polyorganosiloxane; and

b) an organic polymer-containing phase which contains organic polymer without silicone or having polyorganosiloxane content less than the polyorganosiloxane-containing phase.

20. An electrophotographic device comprising:

an electrophotographic photoconductor;

a charging unit configured to charge a latent image carrier;

a light irradiating unit configured to irradiate light imagewisely onto the latent image carrier so as to form a latent electrostatic image thereon;

an image developing unit configured to develop the latent electrostatic image to a developed image; and

a transfer charger configured to transfer the developed image to a recording medium;

wherein the electrophotographic photoconductor comprises;

an electroconductive support and a photoconductive layer thereon; and

an outermost layer of the photoconductive layer comprising particles;

wherein a surface of the particles comprises;

a) a polyorganosiloxane-containing phase which contains polyorganosiloxane; and

b) an organic polymer-containing phase which contains organic polymer without silicone or having polyorganosiloxane content less than the polyorganosiloxane-containing phase.

21. An electrophotographic device comprising:

an electrophotographic photoconductor;

a charging unit configured to charge a latent image carrier;

a light irradiating unit configured to irradiate light imagewisely onto the latent image carrier so as to form a latent electrostatic image thereon;

an image developing unit configured to develop the latent electrostatic image to a developed image; and

a transfer charger configured to transfer the developed image to a recording medium;

wherein the electrophotographic photoconductor comprises;

an electroconductive support; and

a photoconductive layer formed on the electroconductive support;

wherein an outermost layer of the photoconductor comprises

an acryl-modified polyorganosiloxane comprising

a) a main chain of a polyorganosiloxane; and

b) a graft chain of an acryl polymer without containing silicon;

wherein the acryl-modified polyorganosiloxane is prepared by emulsion graft copolymerizing of a polyorganosiloxane compound represented by the following formula (I) and a (meth)acrylic acid ester represented by the following formula (II) or a mixture of the (meth)acrylic acid ester and a monomer copolymerizable with the (meth)acrylic acid ester via emulsion graft copolymerization;

Formula (I)

in the Formula (I),

each of R₁, R₂ and R₃ is a hydrocarbon group having 1 to 20 carbon atoms and R₁, R₂ and R₃ may be identical or different, or be halogenated;

Y is an organic group containing either a radical reactive group or SH group or both of them;

each of Z₁ and Z₂ is a hydrogen atom, lower alkyl group or one represented by the following formula (n), and Z₁ and Z₂ may be identical or different;

m is a plus integer of 10,000 or less; and

n is an integer of 1 or more;

in the Formula (n)

each of R₄ and R₅ is a hydrocarbon group or a halogenated hydrocarbon group having 1 to 20 carbon atoms and R₄ and R₅ may be identical or different; and

R₆ is a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group, an organic group containing either a radical reactive group or SH group or both of them;

in the Formula (II);

R₇ is a hydrogen atom or a methyl group; and

R₈ is at least any one member selected from the group consisting of an alkyl group, alkoxy-substituted alkyl group, cyclo alkyl group and aryl group.

22. A process cartridge comprising an electrophotographic photoconductor which comprises:

an electroconductive support and a photoconductive layer thereon,

the outermost layer of the photoconductive layer comprises an acryl-modified polyorganosiloxane comprising

a) a main chain of a polyorganosiloxane; and

b) a graft chain of an acryl polymer without containing silicon;

wherein the acryl-modified polyorganosiloxane is prepared by emulsion graft copolymerizing of a polyorganosiloxane compound represented by the following formula (I) and a (meth) acrylic acid ester represented by the following formula (II) or a mixture of the (meth)acrylic acid ester and a monomer copolymerizable with the (meth)acrylic acid ester via emulsion graft copolymerization;

Formula (I)

in the Formula (I),

each of R₁, R₂ and R₃ is a hydrocarbon group having 1 to 20 carbon atoms and R₁, R₂ and R₃ may be identical or different, or be halogenated;

Y is an organic group containing either a radical reactive group or SH group or both of them;

each of Z₁ and Z₂ is a hydrogen atom, lower alkyl group or one represented by the following formula (n), and Z₁ and Z₂ may be identical or different;

m is a plus integer of 10,000 or less; and

n is an integer of 1 or more;

in the Formula (n)

each of R₄ and R₅ is a hydrocarbon group or a halogenated hydrocarbon group having 1 to 20 carbon atoms and R₄ and R₅ may be identical or different; and

R₆ is a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group, an organic group containing either a radical reactive group or SH group or both of them;

in the Formula (II);

R₇ is a hydrogen atom or a methyl group; and

R₈ is at least any one of an alkyl group, alkoxy-substituted alkyl group, cyclo alkyl group and aryl group.