| 摘要 |
PURPOSE:To prevent an overshoot at the time of transmittion to the printing state, by executing a heating electric conduction control, too, by a chopping output of a frequency corresponding to the printing state through a comparator, etc. in accordance with a detected temperature, and reducing the width of a control temperature. CONSTITUTION:In accordance with a stand-by state command from a terminal 19a, a comparison reference temperature of a comparator 21b is set extending from the upper limit 180 deg.C, etc. of a print state to its lower limit, and simultaneously, to the upper limit 160 deg.C, etc. of a stand-by state, and also, an output frequency of a chopping generating circuit 23 is made to correspond to the stand-by state. In the stand-by state, in case a temperature of a heat fixing roller 11 through a temperature detecting element 16 is below the lower limit temperature 140 deg.C, etc., the circuit 23 becomes a non-operating state through a chopping operation controlling circuit 22, and an electric conduction to a heater of the roller 11 is executed by a relay controlling circuit 24. At the time of reaching >=140 deg.C, a print available signal is outputted from a comparator 21a and the circuit 23 becomes an operating state, and heating is brought to a chopping control. At the time of printing, as well, the operation is executed in the same way, the width of a control temperature can be reduced, and also, an overshoot at the time of migrating the state is prevented.
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