| 摘要 |
The invention relates to an electrophotographic printer which can make printing first on the front side of a sheet of paper and then on the back side of the same sheet with conformity between the front and back sides in the head-bottom arrangement of the printed images. The printer has a photocounductive drum which can be rotated both in a normal direction and in the reverse direction, an exposure unit to produce electrostatic latent images on the drum surface, first developing means for developing the latent images with a toner when the drum is rotating in the normal direction, second developing means for developing the latent images with a toner when the drum is rotating in the reverse direction, a transfer unit for transferring the developed images to a sheet of paper, and first and second fixing means which are oppositely arranged with respect to the transfer unit. For printing on the front side of the paper sheet, the sheet is passed through the transfer unit in a first direction toward the first fixing means while the drum is rotating in the normal direction. For printing on the back side of the sheet, the sheet is further conveyed by a returning route which turns so as to reverse the sheet and extends to the transfer unit, and, while the drum is rotating in the reverse direction, the reversed and returned sheet passes through the transfer unit in the opposite second direction toward the second fixing means. <IMAGE> |
