| 摘要 |
PURPOSE:To shorten the replacement time of developing device by driving a revolution unit which revolves plural developing units in a parallel state and revolving the developing devices forward or backward in closer directions within 180 deg. selectively. CONSTITUTION:An original is set on an original platen 2 and a developing device 14 is moved away from a photosensitive drum 12 firstly. Then, a motor 39 for selection is operated to rotate rotary frames 34a and 34b, and the developing devices 27a-27d are revolved in the parallel state until a selected developing unit faces the photosensitive drum 12. Then, the developing device 14 is moved toward the photosensitive drum 12 to set the selected developing unit opposite the photosensitive drum 12 closely. In this state, a copy is taken in the selected color. The developing units 27a-27d are revolved in closer directions within 180 deg. when replaced. Thus, the replacement time of the developing units is shortened. |
