| 摘要 |
PURPOSE:To obtain an excellent image without any possibility by color mixing by providing a bias means, a reverse bias means, and their switching means, and putting only a selected developing sleeve in rotary motion and applying a developing bias. CONSTITUTION:The copying machine which has the 1st and the 2nd developing devices 3 and 4 is provided with a bias electric power source 41 which applies the developing bias during development, a reverse bias power source 42, a contact E with contacts A and B, and a contact F with contacts C and D. Then when a developing device 3 is selected on a console panel, a developing panel 3a starts operating at a specific speed and the contact E is connected to the contact A to apply the developing bias to the developing sleeve 3a. The developing sleeve 4a of the developing device 4, on the other hand, is still stopped and the contact F is still connected to the contact D, so a developed image on a drum 1 which is developed by the developing device 3 is no affected by the developing sleeve 4a at all and there is no possibility of color mixing. |
