| 摘要 |
PURPOSE:To provide an image forming device capable of restraining an undesired copied matter from being formed and reducing copying cost. CONSTITUTION:In this image forming device 2, whether or not an image exists on the rear face of a document D is checked in the case of feeding the document D through size sensors 38a and 38b incorporated in a document feeder 10. When the image exists on the rear face of the document and the mode of transfer paper is a double sided mode, the fed document D is reversed as it is, and copying is orderly performed to the rear surface first. The size sensors 38a and 38b detect the intensity of reflected light from the document D so as to decide the presence or absence of the image. In such a case, the base part and the image part of the document are respectively decided according as sensor output is 0<=X<A2i, or A2i<=X<A1i. |
