| 摘要 |
PROBLEM TO BE SOLVED: To make the rotational torque of a rotary sleeve possible to be small and to make realizable a power saving by arranging a turnable unipolar magnet in a sleeve and making the magnet turnable at least up to a layer thickness regulating position. SOLUTION: This device is provided with a fixed magnet roller 51 magnetized to have N poles and S poles alternately, the rotary sleeve 52 internally including the roller 51, the sleeve 53 arranged on the upstream side in a rotating direction of the sleeve 52 from a developing position A, and the S-pole magnet 54 turnable with the center shaft of the sleeve 53 as a center. In the case of interrupting the intrusion of the developer 55 into the developing position by such constitution, the magnet 54 is turned to the vicinity of the layer thickness regulating position B, that is, from a state shown by a figure (a) to a state shown by a figure (b). A magnetic bridge is formed by the N pole being the magnetic pole of the roller 51 and the S pole being the magnetic pole of the magnet 54 which are opposed, whereby the intrusion of the developer 55 is interrupted. Thus, the developer con be easily controlled to get in and out of the developing position. |
