| 摘要 |
PROBLEM TO BE SOLVED: To form a high-quality image and to eliminate trouble such as the deterioration of developer, the insufficiency of the electrified amount of the developer, the lowering of image density by preventing ghost that the history of an image is left on a developing sleeve or dotted image irregularity from occurring. SOLUTION: Repulsive magnetic field for peeling the developer is formed by two magnetic poles N2 and N3 adjacent to each other out of plural magnetic poles of a magnet roll 42, and a 1st magnetic substance 48A where a magnetic pole S different from two magnetic poles N2 and N3 is opposed to the developing sleeve 41 in a non-contact state and a 2nd magnetic substance 48B having the same polarity N as two magnetic poles N2 and N3 on the downstream side in the advancing direction of the developer released from the sleeve 41 in the vicinity of the substance 48A are arranged, and the tolerance of the arranging position of the substance 48A to two magnetic poles N2 and N3 and the tolerance of the arranging position of the substance 48B to the substance 48A are set. |
