IP Library › Granted Patent US 10,088,794
Granted Patent B2
US 10,088,794 · App. 15/590,800 · Granted Oct 2, 2018

Image forming apparatus and process cartridge

Inventor: Issei Imamura (Mishima, JP)
Assignee: Canon Kabushiki Kaisha
G03G15/751G03G15/04G03G15/05G03G15/2003
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Quick Facts
Patent No.
US 10,088,794
App. No.
15/590,800
Granted
Oct 2, 2018
Kind
B2
Abstract

An image forming apparatus includes a rotatably supported photosensitive drum, a charging roller configured to charge the photosensitive drum, a developing sleeve configured to develop an electrostatic latent image formed on a surface of the photosensitive drum and collect toner adhered to the photosensitive drum, an electricity removal sheet disposed on a downstream from the charging roller in a direction of movement on a surface of the photosensitive drum and disposed on an upstream side from the developing sleeve and arranged in contact with the photosensitive drum, and an electricity removal high-voltage power supply configured to apply voltage to the electricity removal sheet. The electricity removal high-voltage power supply an image-forming period applies a DC bias having a polarity identical to a charging polarity of the photosensitive drum and having a lower absolute value than that of the charged potential of the photosensitive drum to electricity removal sheet.

Claims (35)

1. An image forming apparatus, comprising:

a rotatable image bearing member;

a charging member configured to charge the image bearing member to make a surface potential of the image bearing member;

a developing member configured to develop an electrostatic latent image formed on a surface of the image bearing member and collect a developer adhered to the image bearing member;

an electricity removal member disposed downstream of the charging member and upstream of the developing member in a rotating direction of the image bearing member and arranged in contact with the image bearing member; and

an applying member configured to apply a direct-current (DC) bias to the electricity removal member in an image-forming period,

wherein the DC bias has a polarity identical to a charging polarity of the image bearing member and has an absolute value lower than that of the surface potential of the image bearing member.

2. The image forming apparatus according to claim 1 , further comprising:

an exposing unit configured to expose the image bearing member,

wherein the applying member applies the DC bias to the electricity removal member, the DC bias having an absolute value higher than that of the surface potential of the image bearing member after exposed.

3. The image forming apparatus according to claim 1 , wherein the applying member in a non-image-forming period applies the DC bias to the electricity removal member, the DC bias having the polarity identical to the charging polarity of the image bearing member in the image-forming period.

4. The image forming apparatus according to claim 3 , wherein the applying member in the non-image-forming period applies the DC bias to the electricity removal member, the DC bias having an absolute value higher than that of the surface potential of the image bearing member in the image-forming period.

5. The image forming apparatus according to claim 1 , wherein the electricity removal member has a surface having undergone an unevenness treatment.

6. The image forming apparatus according to claim 5 , wherein an average of 10 values of intervals between concaves and convexes of the surface having undergone the unevenness treatment of the electricity removal member is smaller than an average particle size of a developer.

7. The image forming apparatus according to claim 1 , wherein the electricity removal member is a sheet-shaped electricity removal sheet.

8. The image forming apparatus according to claim 1 , wherein the electricity removal member is a roller-shaped electricity removal roller.

9. The image forming apparatus according to claim 8 , wherein the electricity removal roller rotates in a direction opposite against the rotating direction of the image bearing member.

10. The image forming apparatus according to claim 1 , wherein the charging member is provided in noncontact with the image bearing member.

11. A process cartridge detachably attached to an image forming apparatus, the process cartridge comprising:

a rotatable image bearing member;

a charging member configured to charge the image bearing member to make a surface potential of the image bearing member;

a developing member configured to develop an electrostatic latent image formed on a surface of the image bearing member and collect a developer adhered to the image bearing member; and

an electricity removal member disposed downstream of the charging member and upstream of the developing member in a rotating direction of the image bearing member and arranged in contact with the image bearing member,

wherein the electricity removal member is applied a direct-current (DC) bias in an image-forming period, the DC bias having a polarity identical to a charging polarity of the image bearing member and having an absolute value lower than that of the surface potential of the image bearing member.

12. The process cartridge according to claim 11 ,

wherein the image forming apparatus has an exposing unit configured to expose the image bearing member; and

wherein the electricity removal member is applied the DC bias having an absolute value higher than that of the surface potential of the image bearing member after exposed by the exposing unit.

13. The process cartridge according to claim 11 , wherein the electricity removal member in a non-image-forming period is applied the DC bias having the polarity identical to the charging polarity of the image bearing member in the image-forming period.

14. The process cartridge according to claim 13 , wherein the electricity removal member in the non-image-forming period is applied the DC bias having an absolute value higher than that of the surface potential of the image bearing member in the image-forming period.

15. The process cartridge according to claim 11 , wherein the electricity removal member has a surface having undergone an unevenness treatment.

16. The process cartridge according to claim 15 , wherein an average of 10 values of intervals between concaves and convexes of the surface having undergone the unevenness treatment of the electricity removal member is smaller than an average particle size of a developer.

17. The process cartridge according to claim 11 , wherein the electricity removal member is a sheet-shaped electricity removal sheet.

18. The process cartridge according to claim 11 , wherein the electricity removal member is a roller-shaped electricity removal roller.

19. The process cartridge according to claim 18 , wherein the electricity removal roller rotates in a direction opposite against the rotating direction of the image bearing member.

20. The process cartridge according to claim 11 , wherein the charging member is provided in noncontact with the image bearing member.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Aug 9, 2017
From: IMAMURA, ISSEI
To: CANON KABUSHIKI KAISHA
Reel/Frame 043236/0248 →
Priority Claims (1)
JP 2016-097589 · May 16, 2016 · national
Continuity (1)
Related Publication 20170329271A1 · Nov 16, 2017