| 摘要 |
PURPOSE:To provide an electrophotographic device capable of obtaining a good-quality image having no image irregularity over a long period without requiring the cleaning or an exchange of a roller member such as an electrification roller by a service man. CONSTITUTION:The surface of an electrification roller 2 is formed with a material having a static friction coefficient smaller than that of the surface of a photoreceptor 1, and a contact pressure changing means changing the contact pressure of the electrification roller 2 to the photoreceptor 1 is formed with a solenoid 32, an L-shaped sheet metal member 19, a cam 18, and springs 12, 31. A microcomputer 50 controls the contact pressure changing means so that the contact pressure is made larger when the electrification roller 2 is kept in contact with the image nonforming region of the photoreceptor 1 than when the electrification roller 2 is kept in contact with the image forming region. The force that a toner is pressed to the photoreceptor 1 is made larger than the force that the toner is pressed to the electrification roller 2, and the toner is moved to the photoreceptor 1 side. |
