| 摘要 |
PURPOSE:To eliminate the distortion of the temperature distribution to prevent the fixing irregularity, and troubles such as offset of a toner and jam, by controlling the heating range of a heating body of a fixing device restrictively in accordance with the size and the passage position of a copy form. CONSTITUTION:The overall length of a heater 11 incorporated in a fixing device such as a heat roller 1 is approximately equal to the length of the roller 1, and the heater 11 is provided with independent heating wires in parts W2 and W3 respectively in accordance with the width of a copy paper. For the fixing process of a small-size copy paper, power is supplied only to the first heating wire 111; and for the fixing processing of a large-size copy paper, power is supplied to the first and the second heating wires 111 and 112. The number of heating wires and their arrangement are various. An example of the circuit which controls automatically the power supply to heating wires selectively in accordance with the copy paper size is shown in figure. |
