Process cartridge and electrophotographic apparatus

• US 6,405,005 B1
• Filed: 07/31/2000
• Issued: 06/11/2002
• Est. Priority Date: 04/30/1998
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tamura, Osamu, Kitamura, Wataru, Saito, Yoshihisa
• Primary Examiner(s): Rodee, Christopher
• Application Number:
  US09/629,417
• Time in Patent Office: 680 Days
• Field of Search: 430/66, 430/110, 430/970, 430/67, 430/108.7, 430/108.6, 430/108.1, 399/176, 399/115, 399/174, 399/159
• US Class Current: 399/159
• CPC Class Codes: G03G 5/0503 Inert supplements
• CPC Class Codes: G03G 5/0539 Halogenated polymers
• CPC Class Codes: G03G 5/056 Polyesters
• CPC Class Codes: G03G 5/0564 Polycarbonates
• CPC Class Codes: G03G 5/0582 Polycondensates comprising sulfur atoms in the main chain
• CPC Class Codes: G03G 5/14708 comprising organic material
• CPC Class Codes: G03G 5/14752 Polyesters
• CPC Class Codes: G03G 5/14756 Polycarbonates
• CPC Class Codes: G03G 5/14778 Polycondensates comprising sulfur atoms in the main chain

Abstract

A process cartridge is disclosed which includes an electrophotographic photosensitive member having a photosensitive layer and a charging means. The charging means has a charging member which is provided in contact with the electrophotographic photosensitive member to charge the photosensitive member electrostatically by applying a voltage formed by superimposing an alternating-current voltage on a direct-current voltage. The photosensitive member has a surface layer which contains at least one of a polyarylate resin having a weight-average molecular weight of 7.5×10³ to 3.7×10⁴ and having a specific structural unit of Formula (1) and a polycarbonate resin having a weight-average molecular weight of 7.5×10³ to 3.7×10⁴ and having a specific structural unit of Formula (2). The photosensitive member further contains fluorine-containing resin particles. Also, an electrophotographic apparatus having the photosensitive member is disclosed.

Claims

1. A process cartridge comprising:

an electrophotographic photosensitive member comprising an electroconductive support and a photosensitive layer provided on the support; and

a charging means having a charging member which is provided in contact with the electrophotographic photosensitive member and charges the electrophotographic photosensitive member electrostatically by applying a voltage formed by superimposing an alternating-current voltage on a direct-current voltage;

said electrophotographic photosensitive member and said charging means being supported as one unit and being detachably mountable to the main body of an electrophotographic apparatus; and

said electrophotographic photosensitive member having a surface layer which contains i) a polycarbonate resin having a weight-average molecular weight of from 7.5×

10³ to 3.7×

10⁴, a degree of dispersion of 3.0 or less and having a structural unit represented by the following Formula (2), and ii) fluorine-containing resin particles

 

wherein X₂ represents —

CR₂₃R₂₄—

(where R₂₃ and R₂₄ are the same or different and each represent a hydrogen atom, a trifluoromethyl group, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group), a substituted or unsubstituted cycloalkylidene group, a substituted or unsubstituted α

,ω

-alkylene group, a single bond, —

O—

, —

S—

, —

SO—

or —

SO₂—

; and

R₁₅ to R₂₂ are the same or different and each represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group.

2. The process cartridge according to claim 1, wherein said surface layer of the electrophotographic photosensitive member further contains a polycarbonate resin of said Formula (2) having a weight-average molecular weight more than 3.7×

10⁴.

3. The process cartridge according to claim 1, wherein said fluorine-containing resin particles are selected from the group consisting of tetrafluoroethylene resin, trifluoroethylene resin, hexafluoropropylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluorodichloroethylene resin, and a copolymer of any of these resins.

4. The process cartridge according to claim 1, wherein said surface layer of the electrophotographic photosensitive member further contains a fluorine-containing comb graft polymer.

5. The process cartridge according to claim 1, wherein said surface layer of the electrophotographic photosensitive member further contains an antioxidant.

6. The process cartridge according to claim 5, wherein said antioxidant is at least one of a hindered phenol antioxidant and a phosphorus antioxidant.

7. The process cartridge according to claim 1, which further comprises a developing means for forming a toner image by the use of a toner;

said toner having toner particles, a first inorganic fine powder having a number-average particle diameter of 0.10 μ

m or smaller and a second inorganic fine powder having a number-average particle diameter of from 0.12 μ

m to 3.0 μ

m.

8. The process cartridge according to claim 7, wherein said first inorganic fine powder is a fine silicic acid powder.

9. The process cartridge according to claim 8, wherein said second inorganic fine powder is selected from the group consisting of strontium titanate, cerium oxide and titanium oxide.

10. The process cartridge according to claim 7, wherein said first inorganic fine powder has been subjected to coupling treatment and thereafter oil treatment.

11. The process cartridge according to claim 7, wherein said second inorganic fine powder is selected from the group consisting of strontium titanate, cerium oxide and titanium oxide.

12. The process cartridge according to claim 7, wherein said toner has a weight-average particle diameter of from 3.5 μ

m to 6.5 μ

m and toner particles having particle diameters of from 2.00 μ

m to 3.17 μ

m in a content of from 5% by number to 40% by number of the whole toner.

13. The process cartridge according to claim 7, wherein said toner contains a magnetic material.

14. An electrophotographic apparatus comprising:

an electrophotographic photosensitive member comprising an electroconductive support and a photosensitive layer provided on the support;

a charging means having a charging Member which is provided in contact with the electrophotographic photosensitive member and charges an electrophotographic photosensitive member electrostatically by applying a voltage formed by superimposing an alternating-current voltage on a direct-current voltage;

an exposure means for exposing to light the electrophotographic photosensitive member charged, to form an electrostatic latent image;

a developing means for developing the electrostatic latent image by the use of a toner, to form a toner image; and

transferring to a transfer medium the toner image formed;

said electrophotographic photosensitive member having a surface layer which contains i) a polycarbonate resin having a weight-average molecular weight of from 7.5×

10³ to 3.7×

10⁴, a degree of dispersion of 3.0 or less and having a structural unit represented by the following Formula (2), and ii) fluorine-containing resin particles

 

wherein X₂ represents —

CR₂₃R₂₄—

(where R₂₃ and R24 are the same or different and each represent a hydrogen atom, a trifluoromethyl group, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group), a substituted or unsubstituted cycloalkylidene group, a substituted or unsubstituted α

,ω

-alkylene group, a single bond, —

O—

, —

S—

, —

SO—

or —

SO₂—

; and

R₁₅ to R₂₂ are the same or different and each represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group.

15. The electrophotographic apparatus according to claim 14, wherein said surface layer of the electrophotographic photosensitive member further contains a polycarbonate resin of said Formula (2) having a weight-average molecular weight more than 3.7×

10⁴.

16. The electrophotographic apparatus according to claim 14, wherein said fluorine-containing resin particles are selected from the group consisting of tetrafluoroethylene resin, trifluoroethylene resin, hexafluoropropylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluorodichloroethylene resin, and a copolymer of any of these resins.

17. The electrophotographic apparatus according to claim 14, wherein said surface layer of the electrophotographic photosensitive member further contains a fluorine-containing comb graft polymer.

18. The electrophotographic apparatus according to claim 14, wherein said surface layer of the electrophotographic photosensitive member further contains an antioxidant.

19. The electrophotographic apparatus according to claim 18, wherein said antioxidant is at least one of a hindered phenol antioxidant and a phosphorus antioxidant.

20. The electrophotographic apparatus according to claim 14, wherein said toner has toner particles, a first inorganic fine powder having a number-average particle diameter of 0.10 μ

m or smaller and a second inorganic fine powder having a number-average particle diameter of from 0.12 μ

m to 3.0 μ

m.

21. The electrophotographic apparatus according to claim 20, wherein said first inorganic fine powder is a fine silicic acid powder.

22. The electrophotographic apparatus according to claim 21, wherein said second inorganic fine powder is selected from the group consisting of strontium titanate, cerium oxide and titanium oxide.

23. The electrophotographic apparatus according to claim 20, wherein said first inorganic fine powder has been subjected to coupling treatment and thereafter oil treatment.

24. The electrophotographic apparatus according to claim 20, wherein said second inorganic fine powder is selected from the group consisting of strontium titanate, cerium oxide and titanium oxide.

25. The electrophotographic apparatus according to claim 20, wherein said toner has a weight-average particle diameter of from 3.5 μ

m to 6.5 μ

m and toner particles having particle diameters of from 2.00 μ

m to 3.17 μ

m in a content of from 5% by number to 40% by number of the whole toner.

26. The electrophotographic apparatus according to claim 20, wherein said toner contains a magnetic material.