Developing roller and image formation apparatus

• US 20020114649A1
• Filed: 12/19/2001
• Published: 08/22/2002
• Est. Priority Date: 12/22/2000
• Status: Active Grant

• Current Assignee: Bridgestone Corporation
• Original Assignee: Bridgestone Corporation
• Inventors: Ohuchi, Takao
• Granted Patent: US 6,580,892 B2
• Time in Patent Office: Days
• US Class Current: 399/286
• CPC Class Codes: G03G 15/0818 characterised by the structure of the donor member, e.g. surface properties

Abstract

There are disclosed a developing roller comprisig a shaft having good electroconductivity and an electroconductive elastic layer which is formed on the outside periphery of the shaft, and which has a thermal conductivity of at least 0.15 W/m·K; and an image formation apparatus equipped with the developing roller. The above developing roller is capable of suppessing temperature rise of the roller surface, thereby preventing a developer from being adhesively fixed to the roller surface, suppessing wear on the roller surface, suppessing the generation of cracking, crazing and the like on the roller end, and thus affording favorable images for a long period of time.

Claims

1. A developing roller which comprises a shaft having good electroconductivity and an electroconductive elastic layer formed on the outside periphery of said shaft, supports a developer on its surface to form thin films thereof and in this state, rotates in contact with or in close vicinity to the surface of a latent image preserving body that preserves an electrostatic image on its surface, and thus supplies the developer to the surface of the latent image preserving body so as to visualize an electrostatic image on the surface of the latent image preserving body, said electroconductive elastic layer having a thermal conductivity of at least 0.15 W/m·

K.

2. The developing roller according to claim 1, wherein an elastic body which constitutes the electroconductive elastic layer is at least one non-foamed elastic body or foamed elastic body that are selected from the group consisting of silicone rubber, urethane rubber, polybutadiene based rubber and isoprene rubber.

3. The developing roller according to claim 1, wherein the electroconductive elastic layer has Asker C hardness in the range of 30 to 90 degrees.

4. The developing roller according to claim 1, wherein the electroconductive elastic layer has a specific volume resistance in the range of 10³ to 10¹⁰ Ω

·

cm.

5. The developing roller according to claim 1, wherein the electroconductive elastic layer has a resin coating layer on the surface thereof.

6. The developing roller according to claim 5, wherein a resin which constitutes the resin coating layer is at least one member selected from the group consisting of melamine resin, phenolic resin, alkyd resin, fluororesin, polyamide resin and silicone resin.

7. An an image formation apparatus comprising a latent image preserving body capable of preserving an electrostatic image on the surface thereof and a developing roller which is placed so as to rotate in contact with or in close vicinity to the surface of the latent image preserving body along the surface of the aforesaid latent image preserving body, which supports a developer on its surface to form thin films thereof and which supplies the developer to the surface of the latent image preserving body so as to visualize an electrostatic image on the surface of the latent image preserving body, wherein the developing roller as set forth in any of the preceding Claims is employed as the developing roller.