| 摘要 |
PURPOSE:To simplify the structure around a photosensitive drum by making a developing device usable also for cleaning by bias switching and detecting the concentration of toner and changing a bias for cleaning. CONSTITUTION:A cyan toner image on a photosensitive drum 5c of the first transfer station C is transferred onto a sheet of transfer paper at the third rotation after exposure and developing, that is, after developing three times. A magenta toner image on a photosensitive drum 5m of the second station M is transferred onto a sheet of transfer paper after developing twice, and only a yellow toner image on a photosensitive drum 5y of the third transfer station Y is directly transferred onto a sheet of transfer paper. In each transfer station, cleaning is made by bias switching in a developing section after transferring. As cleaning function is given to the developing device 7, the device can be made compact. |
