| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of maintaining uniformity of contact pressure between a photoreceptor and an electrifying roller in the longitudinal direction without the need of use of a backup roll, and thereby forming stably a high grade electrophotographic image. SOLUTION: The image forming apparatus includes an electrifying roller having a conductive mandrel member and a conductive elastic layer formed around the outer circumference of the conductive mandrel member, and a photoreceptor. The conductive mandrel member is made of a ferromagnetic material. An electromagnetic coil is disposed at each of both end parts of the conductive mandrel member so as to generate a magnetic field in the longitudinal direction of the conductive mandrel member. A rod-like electromagnet or magnet is disposed separate from the electrifying roller at a position on the opposite side to the photoreceptor with respect to the electrifying roller. The central axis of the conductive mandrel member and the central axis of the rod-like electromagnet or magnet are substantially parallel. The electrifying roller and the photoreceptor are contacted utilizing the repulsion of the magnetic force functioning between the conductive mandrel member with the electromagnetic coil disposed and the rod-like electromagnet or magnet. COPYRIGHT: (C)2011,JPO&INPIT
|
