| 摘要 |
PROBLEM TO BE SOLVED: To prevent calcium carbonate from adhering to a fixing roller even when transfer paper containing calcium carbonate passes and to prevent the offset of toner by applying negative bias voltage to the fixing roller and a pressure roller respectively and making potential on the pressure roller side low when the transfer paper on which unfixed negative toner lies passes. SOLUTION: The bias voltage is applied to the fixing roller 1 and the pressure roller 6 so that negative potential on the roller 6 side may be higher. For example, the bias voltage 10 being DC -600 V is applied to the core bar 4 of the roller 1, and the bias voltage 11 being DC -800 V is applied to the core bar 7 of the roller 6. Therefore, the negative toner 13 is left on the transfer paper without offsetting both to the rollers 1 and 6. In the case of the transfer paper containing much calcium carbonate, calcium carbonate having a positive polarity gradually adheres to the roller 1 but is shifted to the side of the roller 6 having low potential, so that there is no fear that the surface potential of the roller 1 gets high.
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