| 摘要 |
PURPOSE:To achieve a reduction in cost and miniaturization by detecting an output current by means of a detection circuit when a high voltage power source controls a voltage to make it constant, measuring the impedance of a transfer member, and determining a transfer voltage. CONSTITUTION:The high voltage power source 5 is provided with the detection circuit' 11, which detects an output current, and a constant voltage circuit 12, which controls the output in order to obtain a constant voltage; this power source 5 controls the output voltage by measuring the impedance of a transfer roller 6 from the output of the detection circuit 11 obtained when the control is exerted to make the voltage constant. When the transfer roller 6 is subjected to the impedance measurement, a number of outputs of different voltages are supplied, thereby carrying out the impedance measurement a number of times. In such a manner, the high voltage power source 5 controls the output voltage to make it constant before transfer, and measures the impedance of the transfer member by detecting by means of the detection circuit 11 the current outputted to the transfer roller 6 at that time, and determines the transfer voltage suitable for the impedance. Thus, the optimum transfer can be effected. |
