| 摘要 |
PURPOSE:To make an operation for switching a recording condition needless and to suppress the rising of the cost of a device by altering the level of a power source according to the recording color of a recording unit which is loaded and unloaded, identifying the level on a device main body side and setting the condition of a recording process. CONSTITUTION:Zener diode ZDA whose voltage is 250V and Zener diode ZDB whose voltage is 150V are provided in a developing unit 40A incorporating black toner and in a developing unit 40B incorporating color toner respectively. Therefore, the voltage of the output terminal of a developing bias power source 110 is changed to -250V when the developing unit 40A is loaded in the device main body. A comparator 120 is connected to the output terminal of the developing bias power source 110 and current switching circuit 130 switches the current value of a transfer corona power source 140 according to a developing color based on the binary signal outputted from the comparator 120. Namely, the developing bias voltage and the transfer current are switched according to the sort of the toner used so as to execute the optimum recording. |
