Image forming apparatus and toner

• US 20060062594A1
• Filed: 09/13/2005
• Published: 03/23/2006
• Est. Priority Date: 09/17/2004
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Nagashima, Hiroyuki, Kawasumi, Masanori, Arai, Yuji, Tomita, Masami, Tawada, Takaaki, Shintani, Takeshi, Amemiya, Ken, Koike, Toshio, Yoneda, Takuzi, Mizuishi, Haruji, Ojimi, Tokuya, Uchitani, Takeshi, Yanagida, Masato, Kuwahara, Nobuo
• Granted Patent: US 7,539,451 B2
• Time in Patent Office: Days
• US Class Current: 399/159
• CPC Class Codes: G03G 15/0233 Structure, details of the charging member, e.g. chemical composition, surface properties
• CPC Class Codes: G03G 15/025 by bringing a charging member in the vicinity with the member to be charged, e.g. proximity charging, forming microgap

Abstract

An image forming apparatus having an image support body configured to support a latent image, a charging member configured to provide a substantially uniform charge to a surface of the image support body and a spacer coupled to the charging member and configured to contact the image support body to maintain a gap between the image support body and the charging member. A cleaning part is configured to clean the surface of the image support body after developer is applied to the image support body and transferred to a recording medium. The cleaning part is configured to satisfy the relationship A+B≦C, where A is a width of the effective charging area of the charging member that charges a surface of the image support body, B is a total width of the spacer that contacts the image support body, and C is a width of cleaning part that contacts the image support body.

Claims

1. An image forming apparatus comprising:

an image support body configured to support a latent image;

a charging member configured to provide a substantially uniform charge to a surface of the image support body;

a spacer coupled to said charging member and configured to contact said image support body to maintain a gap between the image support body and the charging member;

an exposing part configured to expose the charged surface of the image support body to write the latent image based on image data;

a developing part configured to develop the latent image by supplying toner particles to the latent image formed on the surface of the image support body to make the latent image a visible image;

a transferring part configured to transfer the visible image on the surface of the image support body onto a transferring medium;

a cleaning part configured to clean the surface of the image support body after the transferring, said cleaning part being configured to satisfy the relationship A+B≦

C, where A is a width of the effective charging area of the charging member that charges a surface of the image support body, B is a total width of the spacer that contacts the image support body, and C is a width of cleaning part that contacts the image support body.

2. An image forming apparatus as claimed in claim 1, wherein the charging member is further configured to use DC and AC bias voltages to provide the substantially uniform charge on a surface of the image support body.

3. An image forming apparatus as claimed in claim 1, further comprising a developing part that develops a latent image formed on the surface of the image support body, said developing part configured to satisfy the relationship D<

A, where D is a width of the developing part.

4. An image forming apparatus as claimed in claim 1, the image forming apparatus further comprising a lubricant applying part configured to apply the lubricant to the surface of the image support body.

5. An image forming apparatus as claimed in claim 4, wherein the relationship A+B≦

E≦

C is satisfied, where E is a width of lubricant applying part that applies a lubricant to the surface of the image support body.

6. An image forming apparatus as claimed in claim 4, further comprising a shield part configured to contact a contact surface of the image support body at an end of the image support body, wherein the lubricant applying part is configured to apply the lubricant to the contact surface of the image support body and the shield part.

7. An image forming apparatus as claimed in claim 1, further comprising a charging member cleaning part configured to clean the surface of the charging member, wherein the relationship A+B≦

F is satisfied, where F is a width of the charging member cleaning part that cleans the surface of the charging member.

8. The image forming apparatus as claimed in claim 1, wherein an average roundness of each of the toner particles is greater than or equal to 0.93 and smaller than or equal to 1.00.

9. The image forming apparatus as claimed in claim 1, wherein each of the toner particles has a ratio (Dv/Dn) of the volume average particle diameter (Dv) to a number average particle diameter (Dn), that is between 1.00 through 1.40.

10. The image forming apparatus as claimed in claim 1, wherein each of the toner particles has shape defined by a major axial length r1, a minor axial length r2 and a thickness r3, where r1≧

r2≧

r3, and ratios r2/r1 and r3/r2 are between 0.5 and 1.0 and between 0.7 and 1.0, respectively.

11. Toner for a development of an electrophotography process in an image forming apparatus having a non-contact charging member, said toner comprising toner particles having a volume average particle diameter (Dv) from 3 to 8 μ

m, wherein the image forming apparatus includes;

an image support body configured to support a latent image;

a charging member configured to provide a substantially uniform charge on a surface of the image support body;

a spacer coupled to said charging member and configured to contact said image support body to maintain a gap between the image support body and the charging member;

an exposing part configured to expose the charged surface of the image support body to write the latent image based on image data;

a developing part configured to develop the latent image by supplying toner particles to the latent image formed on the surface of the image support body to make the latent image a visible image;

a transferring part configured to transfer the visible image on the surface of the image support body onto a transferring medium;

a cleaning part configured to clean the surface of the image support body after the transferring, said cleaning part being configured to satisfy the relationship A +B <

C, where A is a width of the charging member that charges a surface of the image support body effectively, B is a total width of the spacer that contacts the image support body, and C is a width of cleaning part that contacts the image support body.

12. The toner as claimed in claim 11, wherein the toner is prepared by a method comprising:

dispersing or dissolving toner constituents comprising a polyester prepolymer having a functional group having a nitrogen atom, a polyester resin, a colorant, and a release agent in an organic solvent to prepare a toner constituent liquid; and

dispersing the toner constituent liquid in an aqueous medium having a compound capable of reacting with the functional group of the polyester prepolymer to perform at least one of a crosslinking reaction and an elongation reaction of the polyester prepolymer and to form toner particles in the aqueous medium.

13. The toner as claimed in claim 11, wherein an average roundness of each of the toner particles is greater than or equal to 0.93 and smaller than or equal to 1.00.

14. The toner as claimed in claim 11, wherein each of the toner has a ratio of the volume average particle diameter (Dv) to a number average particle diameter (Dn), that is, Dv/Dn, is between 1.00 through 1.40.

15. The toner as claimed in claim 11, wherein each of the toner particles has shape defined by a major axial length r1, a minor axial length r2 and a thickness r3, where r1≧

r2≧

r3, and ratios r2/r1 and r3/r2 are between 0.5 and 1.0 and between 0.7 and 1.0, respectively.

16. An image forming apparatus comprising:

an image support body configured to support a latent image;

means for charging a surface of the image support body uniformly;

means for maintaining a gap between the image support body and the means for charging;

means for exposing the charged surface of the image support body to write a latent image based on image data;

means for developing the latent image by supplying toner particles to the latent image formed on the surface of the image support body to make the latent image a visible image;

means for transferring the visible image on the surface of the image support body onto a transferring medium;

means for cleaning the surface of the image support body after the transferring such that a number of said toner particles bonded to said means for maintaining a gap is reduced.

17. A method for producing improved images in an image forming apparatus, comprising:

positioning a charging member adjacent to an image support body, the charging member being configured to charge a surface of the image support body;

providing a spacer in contact with said charging member and image support body such that an area of the charging member is maintained at a gap distance from an area of the image support body;

providing a cleaning member in contact with said image support body, the cleaning member having a predetermined width that reduces an amount of toner particles that can bond to the spacer during image formation such that said gap distance is maintained substantially constant over time.

18. The method of claim 17, wherein said predetermined width satisfies that relationship A+B≦

C, where A is a width of the area of the charging member that is maintained at a gap distance from an area of the image support body, B is a total width of said spacer and C is said predetermined width of the cleaning member.

19. The method of claim 18, further comprising providing a developing part adjacent to said image support body and configured to supply said toner to said image support body, wherein a width of the developing part satisfies the relationship D<

A, where D is a width of the developing part.

20. The method of claim 18, further comprising providing a lubricant applying part adjacent to the image support body and configured to apply lubricant to a surface of the image support body, wherein the lubricant applying part has a width E that satisfies the relationship A+B≦

E≦

C.

21. The method of claim 18, further comprising providing a charging member cleaning part adjacent to said charging member and configured to clean a surface of the charging member, wherein the charging member cleaning part has a width F which satisfies the relationship A+B≦

F.