| 摘要 |
PURPOSE: To bring the application of a developing bias voltage to each color developing means into non-operating state in the case of forming a black image by using a simple mechanism and controlling the mechanism. CONSTITUTION: The device is connected to a constant voltage power supply by joining a lead wire I for connecting each developing sleeve 130(Y), 130(M) and 130(C) of developing devices 13(Y), 13(M) and 13(C) in parallel and a lead wire II for connecting the developing sleeve 130(K) of a developing device 13(K) to a socket S on the device body side through a plug P on a cartridge 30 side. In the case of forming the color image, a switch SW on a power source side is turned on so as to impress the developing bias voltage on all the developing sleeves, in the case of forming the monochromatic image, the switch SW is turned off so as to impress the developing bias voltage only on the developing sleeve 13(K). |
