| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a developing device capable of preventing a developing hysteresis phenomenon while preventing the retention of developer by appropriately forming a magnetic brush, and to provide an image forming apparatus. <P>SOLUTION: Magnet members M are separately disposed on the roller shafts 20a and 21b of a developing roller 20 and a magnetic roller 21. The magnet members MS and MN1 are arranged facing each other so that the polarities thereof may differ from each other, and unrotatably supported in the circumferential direction. The magnet member MS of the developing roller 20 is constituted so that only a fixed area thereof may be magnetized with a prescribed width in a direction parallel to the axial line on the surface thereof facing the magnet member MN1 of the magnetic roller 21. Thus, the magnetic force is concentratedly mixed, then, the developing hysteresis phenomenon is prevented without necessitating to stop the image formation, and also, the retention of the developer is prevented. <P>COPYRIGHT: (C)2008,JPO&INPIT |
