| 摘要 |
PURPOSE:To prevent clothes and the body from being contaminated, by setting a collection bias voltage applied to a toner supply roller to be a higher voltage than that of the time of development after the development is ended. CONSTITUTION:In a developing device keeping the toner density on a developing sleeve 6 constant based on a voltage difference between a developing bias applied to the developing sleeve 6 and a collection bias applied to a toner supply roller 10, a collection bias voltage applied to the toner supply roller 10 is made higher than that of the development time, after the development is ended. Accordingly, when a prescribed time elapses after the developing operation is ended, the surface of the developing sleeve is set to a state to have no toner, therefore, even when said device is exchanged with other developing device which contains a developer of a different color, no toner is spilt due to a vibration, etc., at the time of attaching and detaching it, thus the inside of a machine and clothes are not contaminated, and exchanging work of the developing device can be executed in a clean state.
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