| 摘要 |
PURPOSE:To increase the number of colors of toner without any hindrance and to perform development with a proper developing bias corresponding to the kind of toner without any user's switching operation by providing a power source device for the developing bias. CONSTITUTION:The power source device for the developing bias is supplied with electric power of 5V from the control part 6 of a recording device side at such timing that the developing sleeve 4a of a developing device 4 performs development. A transistor Tr is turned on and off with a pulse of tens of kHz supplied from an oscillator 5a to switch a pulse transformer T1, thereby applying the developing bias voltage to the developing sleeve 4a. The developing device unit equipped with the power source device for the developing bias like this is used to detect the kind of toner of the developing device at the recording device side, thereby eliminating the need to control the developing bias voltage. Consequently, even if the number of colors of toner increases, the recording device body need not be altered at all and development is carried out on developing bias condition corresponding to the kind of the toner at any time. |
