Fixing apparatus with controlled heaters

A fixing apparatus for controlling fixing temperature by controlling operations of a plurality of heaters, said apparatus comprising:

• (a) a timer for measuring a period of time for operations of the plurality of heaters;
• (b) a controller for controlling operations of the plurality of heaters in accordance with the measured period of time by the timer;
• and
• (c) a fixing temperature sensor for detecting a fixing temperature;
• wherein the controller turns off all of the plurality of heaters when the sensor detects that the fixing temperature reaches not less than a first predetermined value capable of fixing the first predetermined value representing an upper limit fixing temperature,
• the controller turns on only a part of heaters from among the plurality of heaters and makes the timer to begin measurement when the sensor detects that the fixing temperature reaches not more than the first predetermined value, and
• the controller turns on remaining heaters other than the part of heaters in addition to the part of heaters from among the plurality of heaters when a period of time of continuous operations of the part of the plurality of heaters reaches more than a predetermined period of time.