Power supply apparatus

Abstract

A power supply apparatus includes a power converting unit to convert an AC power input by a power input unit and to supply the AC power to a heating unit, a relay interposed between the power input unit and the power converting unit to prevent supplying the AC power to the power converting unit, an auxiliary power unit to supply a driving power to the relay, and a power interruption unit to prevent supplying the driving power to the relay when the fusing roller is heated over a predetermined temperature. Accordingly, a power capacity required for a thermal switch is significantly lower than when the thermal switch is connected to the heating unit in series, so a thermal switch having low capacity may be used and manufacturing costs may be reduced. Since the AC power supplied from the power input unit to the power converting unit is completely interrupted, an unnecessary power consumption generated in the power converting unit by quiescent power is prevented.

Dependencies are inferred from the claim text.