| 摘要 |
PURPOSE:To offer an image forming device which can accurately discriminate the surface or the back surface of a recording paper based on the quantity of light which is reflected from the recording paper. CONSTITUTION:When the recording paper is carried to a specified position, a light emitting element 41 irradiates the recording paper with the light of a certain emitted light quantity and a light receiving element 42 detects reflected light from the recording paper. By comparing the detected result with a discriminating reference value, the surface or the back surface of the recording paper is discriminated. Furthermore, the received light quantity and the discriminated result are stored. Based on the past received light quantity and the discriminated result which are stored, the discriminating reference value is newly set or the emitted light quantity of the light emitting element 41 is newly decided. |
