| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a duplex/simplex printer and electrophotographic printing device which can print on both the sides of a sheet type substrate without making the device structure complex. <P>SOLUTION: In a duplex mode, an image adjusting device 73 is usable and a 1st toner image (negatively charged) is charged to an opposite polarity (positively charged). The polarity of the 1st image is changed on a photosensitive body and the complexity of the device structure is reduced. Then a bias transfer roll 58 biases the polarity to the opposite polarity (negative) from the polarity of the image. Consequently, a toner image is transferred to an intermediate belt 90. Once a 2nd toner image (negatively charged) is generated, the image adjusting device 73 is not used any more and the bias transfer roll 58 is biased to the opposite polarity (e.g. positive) from the polarity of the 2nd toner image. <P>COPYRIGHT: (C)2003,JPO |
