To obtain an ecological electrophotographic system both-side printer capable of stably carrying a paper and converting the electrostatically charged polarity of unfixed toner on the 1st side of the paper by constituting the printer so that the a roller coming into contact with the 2nd side of the paper may be the counter electrode of a bias roller, among two rollers.
Among two rollers 81 and 83, the roller 81 coming into contact with the 1st side of the paper P6 functions as a bias roller. The bias of 1000 to 6000 V whose polarity is opposite to the electrostatically charged polarity of the toner forming the unfixed toner image is applied on the bias roller 81 by a voltage applying means 82. Among the two rollers 81 and 83, the roller 83 coming into contact with the 2nd side of the paper P6 is the counter electrode of the bias roller 81. Thus, a corona discharge is generated in a fine gap formed just before the bias roller 81 coming into contact with the 1st side of the paper P6, then, a charge is injected into the unfixed toner on the 1st side of the paper P6 and the electrostatically charged polarity is converted.
YAMAGUCHI YOSHIHIRO
OGAMI SHUNSUKE
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