POWER SUPPLY DEVICE, ELECTRONIC APPARATUS THERE WITH, INDUCTION HEATER THEREWITH AND IMAGE PROCESSOR THEREWITH

摘要

PROBLEM TO BE SOLVED: To provide a power supply device which can save energy, has high reliability and is small in size and low in cost and to provide an image processor utilizing an induction heater driven by the power supply device in its electronic picture heat-fixing unit. SOLUTION: A drive circuit 35 is controlled to vary an on-width or an off- width by a control circuit 34 and an inverter 12 is driven to supply a high frequency current to an induction heating coil 2. When a drive circuit 40 is controlled by a thin-out control circuit 39 thinning out signals synchronizing with control signals from the control circuit 34 and an inverter 13 is driven to make both coils 2 and 3 operate, the coil 3 is turned on synchronously with the turning-on of the coil 2. When the coil 2 only is made to operate, the coil 3 is not turned on synchronously with the turning-on of the coil 2. A temperature of a heating element 1 is detected by a thermosensor 11, fed back to respective error amplifiers 33 and 38, and controlled to be a predetermined temperature at reference voltages VZ1 and VZ2.