| 摘要 |
PROBLEM TO BE SOLVED: To form a multicolor image of high definition without streaky unevenness, etc., by removing magnetic carriers from the developer of a first two- component developing unit, from the developer carriers of magnetic one- component developing unit of the second and succeeding stages, restraining the carriers at a fixed place in the developing units, so as to prevent resticking, even if the magnetic carriers are stuck and mixed on the developer carriers. SOLUTION: A magnet roller 424 in the developing sleeve 423 of a second developing unit of the magnetic one-component developing unit is provided with two magnetic poles N2 and S2 out of plural magnetic poles set nearer the downstream side in the rotational direction of the sleeve than a developing part. The second developing unit is provided with a carrier removing member consisting of a magnetic field generating means and this carrier removing member is arranged in a position on the developing sleeve between the magnetic poles N2 and S2 of the magnet roller, that is, in a position of a second developing unit opposite to the vicinity of a position A where the magnetic restraining force distribution Fr of a magnetic field generated from the magnet roller is minimum. |
