| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming device including a switching power supply device of digital control type which performs control according to a load state and capable of suppressing an increase in an EMI peak value and maintaining high power efficiency when changing a switching frequency. <P>SOLUTION: An image forming device comprises: DC voltage generation means 104 for generating a DC voltage from a commercial power supply; power control means 101 of digital control type for switching-controlling a generated DC voltage and supplying electric power corresponding to a load by changing a switching frequency; and one or a plurality of operation units 5 to 13 operating at a specific frequency. The power control means 101 changes the switching frequency so that power supply efficiency almost matches power supply efficiency before change of the switching frequency or meets a power supply efficiency specification value, and the fundamental frequency of a frequency of the operation unit and the multiplication frequency thereof do not match the fundamental frequency of the switching frequency and the multiplication frequency thereof when changing the switching frequency. <P>COPYRIGHT: (C)2013,JPO&INPIT |
