| 摘要 |
PURPOSE:To prevent recording paper from being wrinkled and an unfixed image from deforming by arranging plural heat source heaters which have different heat distributions in a fixing roller and providing a control means which controls the one-off states of those heaters. CONSTITUTION:The fixing roller 2a is heated by its internal heaters 3a and 3b and functions as a heat roller to fix a transfer image on recording paper, but the external-diameter shape of the fixing roller is affected by heat expansion through the heating of the heaters. A control circuit 5 turns on and off the heaters with a signal from a humidity sensor 6 to select the heater 3a at high humidity, the heater 3a at low humidity, or the heaters 3a and 3b alternately at intermediate humidity. The roller shape varies under this power-on control to a reverse crown shape at high humidity, a crown shape at low humidity, and a flat shape at intermediate humidity. Consequently, fixation is carried out without any wrinkle.
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