Process cartridge and electrophotographic apparatus

• US 20030118369A1
• Filed: 08/30/2002
• Published: 06/26/2003
• Est. Priority Date: 08/31/2001
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tanaka, Atsushi, Kobayashi, Hiroyuki, Sakurai, Yuji, Kusaba, Takashi, Nakazawa, Akihiko, Matsuda, Hidekazu, Ashibe, Tsunenori
• Granted Patent: US 6,795,667 B2
• Time in Patent Office: Days
• US Class Current: 399/111
• CPC Class Codes: G03G 15/1605 using at least one intermediate support G03G15/1625 takes precedence
• CPC Class Codes: G03G 21/181 Manufacturing or assembling, recycling, reuse, transportation, packaging or storage
• CPC Class Codes: G03G 21/1821 means for connecting the different parts of the process cartridge, e.g. attachment, positioning of parts with each other, pressure/distance regulation G03G21/1825 takes precedence
• CPC Class Codes: G03G 2215/0177 Rotating set of developing units
• CPC Class Codes: G03G 2221/1642 for the transfer unit

Abstract

A process cartridge which is detachably mountable to a main body of an electrophotographic apparatus, including an electrophotographic photosensitive member to carry a toner image; an intermediate transfer belt having a contact part with the photosensitive member, and a primary transfer unit to primarily transfer the toner image at the contact part from the photosensitive member to the intermediate transfer belt, being integrally supported in one body. After the contact part is formed by the photosensitive member and the intermediate transfer belt being brought into contact with under a linear pressure of 0.5 N/cm and is left for 10 hours in an environment of 45° C./95% RH, differences in the dark portion potential and the light portion potential of the photosensitive member between the contact part and the non-contact part of the photosensitive member are respectively less than 20%, and no crack having a length of not less than 1 μm occurs in any of the surfaces of the photosensitive member and the intermediate transfer belt. An electrophotographic apparatus having the process cartridge is also disclosed.

Claims

1. A process cartridge which is detachably mountable to a main body of an electrophotographic apparatus, integrally comprising:

an electrophotographic photosensitive member to carry a toner image;

an intermediate transfer belt having a contact part with the electrophotographic photosensitive member, and

primary transfer means to primarily transfer the toner image at the contact part from the electrophotographic photosensitive member to the intermediate transfer belt,

wherein after the contact part is formed by the electrophotographic photosensitive member and the intermediate transfer belt being brought into contact with each other under a linear pressure of 0.5 N/cm and left to stand for 10 hours in an environment of 45°

C./95% RH, differences in the dark portion potential and the light portion potential of the electrophotographic photosensitive member between the contact part and the portion being not the contact part of the electrophotographic photosensitive member are respectively less than 20%, and no crack having a length of not less than 1 μ

m occurs in any of the surface of the electrophotographic photosensitive member and the surface of the intermediate transfer belt.

2. The process cartridge according to claim 1, wherein said electrophotographic photosensitive member has a secondary transfer means to further transfer to a transfer material the toner image having been primarily transferred to the intermediate transfer belt from said electrophotographic photosensitive member.

3. The process cartridge according to claim 1, further comprising integrally charge providing means to give electric charges in polarity opposite to the polarity of the toner at the time of said primary transfer to the toner on said intermediate transfer belt to return the toner on said intermediate transfer belt to said electrophotographic photosensitive member at said contact part to clean said intermediate transfer belt.

4. The process cartridge according to claim 1, further comprising integrally electrophotographic photosensitive member cleaning means to clean said electrophotographic photosensitive member.

5. The process cartridge according to claim 4, wherein said electrophotographic photosensitive member cleaning means is blade cleaning means having an elastic blade.

6. The process cartridge according to claim 1 being separable to an electrophotographic photosensitive member unit having said electrophotographic photosensitive member and an intermediate transfer belt unit having said intermediate transfer belt, and having connecting means to connect said electrophotographic photosensitive member unit and said intermediate transfer belt unit.

7. The process cartridge according to claim 1, wherein after said contact part is formed by said electrophotographic photosensitive member and said intermediate transfer belt being brought into contact with each other under a linear pressure of 0.5N/cm and left to stand for 336 hours in an environment of 45°

C./95% RH, differences between the dark portion potential and the light portion potential of said electrophotographic photosensitive member between the contact part and the portion being not the contact part of said electrophotographic photosensitive member are respectively less than 20%.

8. The process cartridge according to claim 1, wherein said intermediate transfer belt has a volume resistivity of 1×

10⁶ to 8×

10¹³ Ω

·

cm and a wall thickness of 40 to 300 μ

m.

9. The process cartridge according to claim 1, wherein said intermediate transfer belt is produced by a production method comprising:

a melt-extrusion step of forming a tubular film from a circular die by means of melt-extrusion;

a diameter controlling step of controlling the diameter of the tubular film by injecting gas into the interior of the tubular film obtained in the melt-extrusion step to adjust the inner volume;

a forming step of forming the tubular film without using any member supporting the tubular film until the tubular film controlled in respect of the diameter in the diameter controlling step is cooled and solidified, and

a cutting step of cutting the tubular film obtained in the forming step to obtain an intermediate transfer belt.

10. The process cartridge according to claim 9, wherein the tubular film formed in said forming step has a wall thickness of not more than one third of die gap of said circular die.

11. The process cartridge according to claim 9, wherein the tubular film formed in said molding step has a diameter of 101 to 300% of that of said circular die.

12. The process cartridge according to claim 1, wherein said intermediate transfer belt is placed over and around two rollers.

13. The process cartridge according to claim 1, wherein at least one of the rollers over and around which said intermediate transfer belt is placed slides by 1 mm or more, and the roller has a mechanism to apply a force of not less than 5N toward the intermediate transfer belt.

14. The process cartridge according to claim 1, wherein said electrophotographic photosensitive member is in the form as a drum of rigid body, and has a diameter of not more than 60 mm.

15. The process cartridge according to claim 1, wherein said electrophotographic photosensitive member has a layer containing a charge transporting material having a film thickness of 10 to 60 μ

m on a support member, and the charge transporting material is in a content of 20 to 80% by weight based on all the weight of the layer containing the charge transporting material.

16. The process cartridge according to claim 15, wherein said layer containing the charge transporting material has a film thickness of 15 to 40 μ

m, and said charge transporting material is in a content of 30 to 60% by weight based on all the weight of the layer containing the charge transporting material.

17. The process cartridge according to claim 1, wherein said electrophotographic photosensitive member has as a photosensitive layer, a lamination type photosensitive layer having a charge generation layer containing charge generation material and a charge transport layer containing charge transporting material and the charge transport layer contains polycarbonate or polyarylate.

18. The process cartridge according to claim 17, wherein said electrophotographic photosensitive member contains a charge transporting material having a structure represented by the following formula (1) or a charge transporting material having a structure represented by the following formula (2).

19. The process cartridge according to claim 18, wherein said electrophotographic photosensitive member contains both of a charge transporting material having a structure represented by said formula (1) and a charge transporting material having a structure represented by said formula (2).

20. An electrophotographic apparatus comprising:

an electrophotographic photosensitive member to carry a toner image;

charging means to electrically charge the electrophotographic photosensitive member;

exposing means to form an electrostatic latent image on the electrophotographic photosensitive member charged with the charging means;

developing means to develop with a toner the electrostatic latent image formed with the exposing means on the electrophotographic photosensitive member to form a toner image on the electrophotographic photosensitive member;

an intermediate transfer belt having a contact part with the electrophotographic photosensitive member to perform, after primary transfer of the toner image from the electrophotographic photosensitive member to the intermediate transfer belt, secondary transfer of the primarily transferred toner image to a transfer material; and

primary transfer means to primarily transfer the toner image from the electrophotographic photosensitive member to the intermediate transfer belt at the contact part; and

comprising a process cartridge integrally supporting at least the electrophotographic photosensitive member, the intermediate transfer belt, and the primary transfer means and being detachably mountable to a main body of the electrophotographic apparatus,

wherein after the contact part is formed by the electrophotographic photosensitive member and the intermediate transfer belt being brought into contact with each other under a linear pressure of 0.5 N/cm and left to stand for 10 hours in an environment of 45°

C./95% RH, differences in the dark portion potential and the light portion potential of the electrophotographic photosensitive member between the contact part and the portion being not the contact part of the electrophotographic photosensitive member are respectively less than 20%, and no crack having a length of not less than 1 μ

m occurs in any of the surface of the electrophotographic photosensitive member and the surface of the intermediate transfer belt.

21. The electrophotographic apparatus according to claim 20, further comprising secondary transfer means to further transfer to a transfer material the toner image having been primarily transferred to the intermediate transfer belt from said electrophotographic photosensitive member.

22. The electrophotographic apparatus according to claim 20, wherein said process cartridge further comprises integrally charge providing means to give electric charges in polarity opposite to the polarity of the toner at the time of said primary transfer to the toner on said intermediate transfer belt to return the toner on said intermediate transfer belt to said electrophotographic photosensitive member at said contact part to clean said intermediate transfer belt.

23. The electrophotographic apparatus according to claim 20, wherein said process cartridge further comprises integrally electrophotographic photosensitive member cleaning means to clean said electrophotographic photosensitive member.

24. The electrophotographic apparatus according to claim 23, wherein said electrophotographic photosensitive member cleaning means is blade cleaning means having an elastic blade.

25. The electrophotographic apparatus according to claim 20, wherein said process cartridge is separable to an electrophotographic photosensitive member unit having said electrophotographic photosensitive member and an intermediate transfer belt unit having said intermediate transfer belt, and has connecting means to connect said electrophotographic photosensitive member unit and said intermediate transfer belt unit.

26. The electrophotographic apparatus according to claim 20, wherein after said contact part is formed by said electrophotographic photosensitive member and said intermediate transfer belt being brought into contact with each other under a linear pressure of 0.5 N/cm and left to stand for 336 hours in an environment of 45°

C./95% RH, differences in the dark portion potential and the light portion potential of said electrophotographic photosensitive member between the contact part and the portion being not the contact part said electrophotographic photosensitive member are respectively less than 20%.

27. The electrophotographic apparatus according to claim 20, wherein said intermediate transfer belt has a volume resistivity of 1×

10⁶ to 8×

10¹³ Ω

·

cm and a wall thickness of 40 to 300 μ

m.

28. The electrophotographic apparatus according to claim 20, wherein said intermediate transfer belt is produced by a production method comprising:

a melt-extrusion step of forming a tubular film from a circular die by means of melt-extrusion;

a diameter controlling step of controlling the diameter of the tubular film by injecting gas into the interior of the tubular film obtained in the melt-extrusion step to adjust the inner volume;

a forming step of forming the tubular film without using any member supporting the tubular film until the tubular film controlled in respect of the diameter in the diameter controlling step is cooled and solidified, and

a cutting step of cutting the tubular film obtained in the forming step to obtain an intermediate transfer belt.

29. The electrophotographic apparatus according to claim 28, wherein the tubular film formed in said forming step has a wall thickness of not more than one third of die gap of said circular die.

30. The electrophotographic apparatus according to claim 28, wherein the tubular film formed in said molding step has a diameter of 101 to 300% of that of said circular die.

31. The electrophotographic apparatus according to claim 20, wherein said intermediate transfer belt is placed over and around two rollers.

32. The electrophotographic apparatus according to claim 20, wherein at least one of the rollers over and around which said intermediate transfer belt is placed slides by 1 mm or more, and the roller has a mechanism to apply a force of not less than 5 N toward the intermediate transfer belt.

33. The electrophotographic apparatus according to claim 20, wherein said electrophotographic photosensitive member is in the form as a drum of rigid body, and has a diameter of not more than 60 mm.

34. The electrophotographic apparatus according to claim 20, wherein said electrophotographic photosensitive member has a layer containing a charge transporting material having a film thickness of 10 to 60 μ

m on a support member, and the charge transporting material is in a content of 20 to 80% by weight based on all the weight of the layer containing the charge transporting material.

35. The electrophotographic apparatus according to claim 34, wherein said layer containing the charge transporting material has a film thickness of 15 to 40 μ

m, and said charge transporting material is in a content of 30 to 60% by weight based on all the weight of the layer containing the charge transporting material.

36. The electrophotographic apparatus according to claim 20, wherein said electrophotographic photosensitive member has as a photosensitive layer, a lamination type photosensitive layer having a charge generation layer containing charge generation material and a charge transport layer containing charge transporting material and the charge transport layer contains polycarbonate or polyarylate.

37. The electrophotographic apparatus according to claim 20, wherein said electrophotographic photosensitive member contains a charge transporting material having a structure represented by the following formula (1) or a charge transporting material having a structure represented by the following formula (2).

38. The electrophotographic apparatus according to claim 37, wherein said electrophotographic photosensitive member contains both of a charge transporting material having a structure represented by said formula (1) and a charge transporting material having a structure represented by said formula (2).