Method for supplying power, and fixing and image forming apparatuses

A method for heating a fixing device, comprising the steps of:

• heating at least two heaters included in the fixing device using AC and DC powers supplied from a commercial power source and an electrical condenser charged by the commercial power source, respectively;
• controlling temperature of the fixing device within a prescribed range during fixing an image onto a recording medium by supplying the DC power to one of the at least two heating members when sheets are continuously fed and the temperature lowers the lowest range;
• and
• controlling the temperature by stopping supplying the DC power only when a power supply stop signal is generated after a prescribed time period has elapsed from when the DC power is supplied, wherein back electromotive force caused in one of the at least two heaters being reduced to an acceptable level within the prescribed time period.

A fixing apparatus, comprising:

• a first heat generating member configured to generate heat upon receiving power from a commercial power source;
• an electrical condenser configured to store charge when charged by the commercial power source;
• a second heat generating member configured to generate heat upon receiving power from the electrical condenser;
• a fixing member heated by the first and second heat generating members and configured to fix an image onto a recording medium;
• and
• a control device configured to restrict the power supplied from commercial power source to the first heat generating member when the temperature of the fixing member starts increasing;
• wherein said electrical condenser starts supplying power to the second heat generating member before the control device terminates restriction of the power.

A fixing apparatus, comprising:

• an electrical condenser configured to store charge when charged by a commercial power source;
• a heat generating member configured to generate heat upon receiving power from the electrical condenser based upon a power supply start signal;
• a fixing member heated by the heat generating member and configured to fix an image onto a recording medium;
• a power supply circuit configured to convey power from the electrical condenser to the heat generating section;
• a switching element configured to close and open the power supply circuit when being turned on and off, respectively;
• and
• a control device configured to output a turn on signal to turn on the switching element when sheets are continuously fed, said control device outputs a turn off signal to turn off the switching element only when a power supply stop signal is generated after a prescribed time period has elapsed from when the power supply start signal is generated.