| 摘要 |
A power supply for use in a printer provides a current progressively small with increasing transfer roller impedance. A reference current section RC sets a voltage Vr indicative of a reference current Ia of an output current Iout of the power supply PS. A voltage generator VG provides an output voltage Vout of the power supply PS. A voltage monitor VM monitors the output voltage to provide a voltage-monitoring signal Vm to an operational section E. The operational section E determines a correction value of the output current Iout on the basis of the voltage Vr and the voltage-monitoring signal Vm. The correction value is progressively small as the voltage-monitoring signal Vm increases. A current controller C controls the voltage generator VG in accordance with an operation result obtained by the operational section E, so that the transfer roller is supplied with a current progressively small with increasing roller impedance but is still charged to a voltage progressively high with increasing roller impedance. |
