IMAGE-BEARING MEMBER PROTECTING AGENT, PROTECTIVE LAYER FORMING DEVICE, IMAGE FORMING METHOD, IMAGE FORMING APPARATUS AND PROCESS CARTRIDGE

• US 20090311014A1
• Filed: 06/16/2009
• Published: 12/17/2009
• Est. Priority Date: 06/16/2008
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Hasegawa, Kunio, Tanaka, Shinya, Nakai, Hiroshi
• Granted Patent: US 7,979,017 B2
• Time in Patent Office: Days
• US Class Current: 399/315
• CPC Class Codes: G03G 21/0094 fatigue treatment of the photoconductor
• CPC Class Codes: G03G 5/005 Materials for treating the recording members, e.g. for cleaning, reactivating, polishing

Abstract

To provide an image-bearing member protecting agent used in an image forming method which includes applying or attaching the agent onto a surface of an image bearing member, the agent including: a fatty acid metal salt and boron nitride, wherein the boron nitride includes secondary particles composed of aggregated fine crystals, and wherein the crystals have an average primary particle diameter of 0.1 μm to 1.0 μm and an average secondary particle diameter of 3.0 μm to 14.0 μm.

Claims

1. An image-bearing member protecting agent used in an image forming method which includes applying or attaching the agent onto a surface of an image bearing member, the agent comprising:

a fatty acid metal salt, and

boron nitride,

wherein the boron nitride includes secondary particles composed of aggregated fine crystals, and

wherein the crystals have an average primary particle diameter of 0.1 μ

m to 1.0 μ

m and an average secondary particle diameter of 3.0 μ

m to 14.0 μ

m.

2. The image-bearing member protecting agent according to claim 1, wherein the fatty acid metal salt is zinc stearate.

3. An image forming apparatus comprising:

an image bearing member which bears a toner image,

a transfer device configured to transfer the toner image borne on the image bearing member onto a transfer medium, and

a protective layer forming device configured to apply or attach an image-bearing member protecting agent onto a surface of the image bearing member, after the toner image has been transferred onto the transfer medium,

wherein the agent comprises a fatty acid metal salt and boron nitride,

wherein the boron nitride includes secondary particles composed of aggregated fine crystals, and

wherein the crystals have an average primary particle diameter of 0.1 μ

m to 1.0 μ

m and an average secondary particle diameter of 3.0 μ

m to 14.0 μ

m.

4. The image forming apparatus according to claim 3, further comprising a cleaning device placed on a downstream side of the transfer device and on an upstream side of the protective layer forming device with respect to the rotational direction of the image bearing member and configured to remove toner which remains on the surface of the image bearing member from the surface by rubbing against the surface.

5. The image forming apparatus according to claim 3, wherein at least a layer formed as the outermost surface of the image bearing member contains a thermosetting resin.

6. The image forming apparatus according to claim 3, wherein the image bearing member is a photoconductor.

7. The image forming apparatus according to claim 5, further comprising a charging device placed in contact with or close to the surface of the image bearing member.

8. The image forming apparatus according to claim 7, further comprising a voltage applying device configured to apply to the charging device a voltage which includes an alternating-current component.

9. The image forming apparatus according to claim 3, wherein the image bearing member is an intermediate transfer medium.

10. The image forming apparatus according to claim 3, wherein a circularity SR of the toner, represented by Equation 1, is in the range of 0.93 to 1.00.

Circularity SR=Circumferential length of circle having the same area as projected particle area/Circumferential length of projected particle image  

 

(Equation

     1)

11. The image forming apparatus according to claim 3, wherein a ratio D₄/D₁ of a weight average particle diameter D₄ of the toner to a number average particle diameter D₁ of the toner is in the range of 1.00 to 1.40.

12. A process cartridge comprising:

an image bearing member which bears a toner image, and

a protective layer forming device provided integrally with the image bearing member and configured to apply or attach an image-bearing member protecting agent onto a surface of the image bearing member after the toner image has been transferred onto a transfer medium,

wherein the agent comprises a fatty acid metal salt and boron nitride,

wherein the boron nitride includes secondary particles composed of aggregated fine crystals, and

wherein the crystals have an average primary particle diameter of 0.1 μ

m to 1.0 μ

m and an average secondary particle diameter of 3.0 μ

m to 14.0 μ

m.

13. The process cartridge according to claim 12, further comprising a cleaning device placed on an upstream side of the protective layer forming device with respect to the rotational direction of the image bearing member and configured to remove toner which remains on the surface of the image bearing member from the surface by rubbing against the surface.

14. The process cartridge according to claim 12, wherein at least a layer formed as the outermost surface of the image bearing member contains a thermosetting resin.

15. The process cartridge according to claim 12, further comprising a charging device placed in contact with or close to the surface of the image bearing member.

16. The process cartridge according to claim 12, wherein a circularity SR of the toner, represented by Equation 1, is in the range of 0.93 to 1.00.

Circularity SR=Circumferential length of circle having the same area as projected particle area/Circumferential length of projected particle image  

 

(Equation

     1)

17. The process cartridge according to claim 12, wherein a ratio D₄/D₁ of a weight average particle diameter D₄ of the toner to a number average particle diameter D₁ of the toner is in the range of 1.00 to 1.40.