| 摘要 |
One or each of a plurality of developing units of a magnetic brush type developing device includes a shield plate which is angularly movable in a space between a cylindrical sleeve, which constitutes a developing roller, and a magnetic body so as to shield a part of magnetic fields which are developed by the magnetic body. The shield plate moves in a reciprocal motion only between a first position corresponding to that where the sleeve scoops a developer and a second position where the developer is separated and not to a position where a main pole magnet for development of the magnetic body is disposed, so that a magnetic field developed by the main pole magnet is not shielded. A member for supporting the shield plate is interposed between the magnetic body and the shield plate.
|
