| 摘要 |
PURPOSE:To provide a fixing device capable of surely preventing offset even in the case of using both of negative toner and positive toner. CONSTITUTION:A bias impressing member 71 is allowed to abut on a fixing roller 8, and a negative(-) bias generating high voltage transformer 51 and a positive(+) bias generating high voltage transformer 52 are connected with the bias impressing member 71 through a bias switching means 6. And the bias switching means 6 is driven by a CPU 4 in accordance with the output of a mode selecting means 2, and in the case the negative mode is selected, the nagative(-) bias generating high voltage transformer 51 is selected, meanwhile, in the case the positive mode is selected, the positive(+) bias generating high pressure transformer 52 is selected, then, each potential is imparted to the surface of the fixing roller 8. |
