| 摘要 |
PROBLEM TO BE SOLVED: To prevent increase in driving current flowing to a primary side of a transformer for increasing AC voltage and prevent degradation of component reliability caused by a temperature rise due to a loss at a drive element even when a load fluctuates, when maintaining a constant level of superimposed voltage to be supplied to the load as an image forming voltage. SOLUTION: A power supply device includes: a step-up transformer 111 for generating an AC voltage, a DC voltage generation circuit 121 for superimposing a DC voltage on the secondary side of the step-up transformer 111, a DC voltage control circuit 122 for controlling the level of the DC voltage generated by the DC voltage generation circuit 121, an auxiliary power circuit 102 for complementing the DC voltage generated by the DC voltage generation circuit 121, and a control part 101 for changing the DC voltage level complementarily output by the auxiliary power circuit 102 according to the DC voltage level generated by the DC voltage generation circuit 121 under the DC voltage control circuit 122 to maintain the DC voltage superimposed on the AC voltage on the secondary side of the step-up transformer 111 at a required voltage. COPYRIGHT: (C)2009,JPO&INPIT
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