| 摘要 |
<p>The fixing heater controlling method has three periods immediately after an AC power-supply voltage begins to be applied to the fixing heater when a heater temperature falls below a target temperature: a first period for controlling only a first heater; a second period for controlling only a second heater following the first period; and a third period for controlling the first and second heaters following the second period. During the first and second periods, the first or second heater is thinning-controlled. At this time, at a cycle of 3 half-waves of the AC voltage applied to the fixing heater, a thinning frequency is changed from a large value to a smaller one. During the third period, first and second sub periods are alternately repeated. In at least one of the first and second sub periods, the first and second heaters are thinning-controlled and the relation of the thinning controls of the two heaters is such that they are complementary to each other on the time axis.</p> |
