| 摘要 |
PURPOSE:To facilitate the exchange of developer and to improve the carrying force of new developer by providing at least one of fixed magnets disposed on a magnetic roll so that the magnetic force of both poles appear on the peripheral surface of a developing sleeve. CONSTITUTION:A main magnet N1 and sub magnets S1 and S2 disposed on the magnetic roll 12A provide the axis of a permanent magnet in a radius direction, and make only either magnetic pole opposite to the developing sleeve 11. But the sub magnet N2 is made to turn both poles of N and S to a peripheral direction so that the magnetic force appears on the peripheral surface of the developing sleeve 11. The sub magnet N2 is arranged and fixed in order to make its same pole S adjacent to the sub magnet S2 which positions on the upper part of the rotation of the developing sleeve 11. Thus, the carrying faculty and the exchangeability of the developer is enhanced even in a developing device where the developing sleeve 11 having a short diameter is used. |
