| 摘要 |
PURPOSE:to uniform the height of bristles of a magnetic brush and to obtain an image of high quality which has uniform density over the entire image plane by uniforming magnetic flux density on the surface of a sleeve in the axial direction of a developing roller. CONSTITUTION:The developing roller consists of the sleeve 1 made of a nonmagnetic body and a magnet roller 2 which has many magnetic poles internally and the sleeve 1 and roller 2 are rotated coaxially. Both end parts of the roller 2 are tapered so that magnetic pole surfaces of magnets are separated from the sleeve 1. Consequently, the magnetic pole surfaces of the magnets are separated from the surface of the sleeve 1 more and more toward both end parts to uniform the magnetic flux density on the surface of the sleeve 1 in the axial direction of the roller 2 within the range of the internal magnets. Thus, the magnetic brush 3 is formed of a developer having uniform height in the axial direction. |
