| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus including a switching power source that suppresses output of an excessive voltage when a main power switch is turned off.SOLUTION: A first power source 60 includes a switching control circuit 610, a first rectification circuit 620, a transformer 630, a second rectification circuit 640, a voltage generation circuit 650, photocouplers 660a and 660b, an excessive voltage protection circuit 670, and a stop circuit 680. The first power source 60 decreases a DC input voltage Vin obtained by rectifying and smoothing an AC voltage (current) supplied from an AC power source 100 through a main power switch PSw, to a DC output voltage Vout having a smaller value than that of the input voltage Vin. When the stop circuit 680 receives, at a timing of transition from turn-on to turn-off of the main power switch PSw, a notification signal CPO notifying that the main power switch PSw is turned off, stops the operation of the switching control circuit 610. |
