| 摘要 |
PROBLEM TO BE SOLVED: To surely prevent an image from being repeatedly formed on an image-printed surface in the case of using the rear side of a paper in an image forming device. SOLUTION: The device is provided with a paper feeding means 13 for feeding a paper, an image forming means for forming the image on the fed paper, an image forming surface pattern detecting sensor 16 for detecting a detection pattern formed on a specified position on each side of the paper, and a non- image forming surface pattern detecting sensor 17, and the detection pattern is formed on the same surface as the image-formed surface of the paper formed by the image forming means. A sequence of printing operations is switched in accordance with the detection result of the detection pattern, and in the case the detection pattern is detected on each side of the paper, the image forming operation is interrupted, and a command display for urging to replace the paper is displayed, and in the case the detection pattern is detected only on the image-formed surface of the paper, the paper to be fed is reversed by a reversing means, thereafter, the paper is fed again. Besides, the detecting patterns are symmetrically formed in two or more positions in the paper carrying direction. |
