Image forming apparatus
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Accused Products
Abstract
This invention is intended to control the amount of power to be supplied to a fusing heater below a maximum applicable current value. The engine controller supplies electricity to both of two heating bodies at the same fixed duty D1. At a phase angle al corresponding to the fixed duty D1, pulse signals ON1 and ON2 are issued in response to a ZEROX signal as a trigger. A current value I1 is detected based on a HCRRT signal from the current detection circuit. The engine controller calculates an upper limit of applicable power duty Dlimit based on the detected current value I1, the fixed duty D1 and the preset applicable current value Ilimit. Then, a PI temperature control is performed at a duty below the upper-limit duty Dlimit.
204 Citations
35 Claims
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1-25. -25. (canceled)
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26. An image forming apparatus comprising:
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a fixing device having a heating unit;
a power supply unit for supplying electricity to the heating unit;
a power control unit for controlling a duty for an ac power source supplied from the power supply unit to the heating unit;
a current detection unit for detecting a current supplied to the heating unit; and
a calculation unit for calculating a maximum duty that can be supplied to the heating unit, based on a current value detected by the current detection unit when the ac power source with a predetermined duty is supplied to the heating unit;
wherein the power control unit controls the ac power source to be supplied from the power supply unit to the heating unit below the maximum duty calculated by the calculation unit. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35)
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Specification