DEVELOPING DEVICE AND IMAGE FORMING APPARATUS HAVING THE SAME

摘要

A developing device includes a magnetic roller, a developing roller, a cover, a first magnetic force generator, a second magnetic force generator with a different polarity, and a movement controller. A roller surface of the magnetic roller holds toner and magnetic carrier, the toner being adhered to the magnetic carrier. The developing roller is arranged to face the magnetic roller. The first magnetic force generator is provided inside the magnetic roller such that a magnetic pole face thereof faces the developing roller. The second magnetic force generator is provided inside the developing roller so as to be able to move between a first position and a second position. A magnetic pole face of the second magnetic force generator faces the magnetic roller at the first position and faces the cover at the second position. The movement controller causes the second magnetic force generator to move between positions.

主权项

1. A developing device comprising:
a magnetic roller whose roller surface holds toner and magnetic carrier, the toner being adhered to the magnetic carrier; a developing roller arranged to face the magnetic roller; a cover covering the developing roller and arranged at a predetermined distance from a roller surface of the developing roller; a first magnetic force generator provided inside the magnetic roller in a state where a magnetic pole face of the first magnetic force generator faces the developing roller; a second magnetic force generator provided inside the developing roller so as to be able to move between a first position and a second position, a magnetic pole face of the second magnetic force generator facing the magnetic roller at the first position and facing the cover at the second position, the first magnetic force generator and the second magnetic force generator having different polarities; and a movement controller causing the second magnetic force generator to move from the first position to the second position, and subsequently to move to the first position.