DEVELOPING DEVICE IN COPIER

摘要

A first developing roller (20) is arranged to hold a red developing agent (DA) on its surface, and is part of a first developing unit (22). A doctor blade (27) provides a sliding contact between a magnetic brush on the surface of the roller and the photo-sensitive drum. A sleeve (33) is provided around a magnetic roll (32) having five magnetic poles (34A-34E), to form the first roller. The sleeve is caused to rotate clockwise by a first driving mechanism (35A). The lower developing unit (23) provides a black developing agent (DB) which is carried by the second developing roller (21). The rotational sleeve (45) of the second roller is caused to rotate anti-clockwise by the second driving mechanism (35B).