| 摘要 |
PURPOSE:To prevent the generation of noise in the image of a recording medium, by mounting the photosensor provided to an exposure part to detect laser beam performing scanning in a main scanning direction and a detection means receiving the signal of said photosensor to detect the width of the recording medium in the scanning direction thereof. CONSTITUTION:Laser beam 15 performing scanning in a main scanning direction C is detected by the photosensors 18-20 arranged to the proper area of an exposure part 4. In this case, three photosensors 18-20 are provided behind the passage of a recording medium 5 so that the difference between the light intensities of laser beam 15 corresponding to the width of the recording medium in the main scanning direction thereof can be detected. When laser beam is detected, a detection means appropriately emits a detection signal and image exposure width in the main scanning direction is appropriately selected corresponding to said detection signal without directly contacting with the recording medium 5 and printing operation corresponding to the width of the recording medium in the main scanning direction can be performed. That is, because the width is detected by the photosensors, the generation of noise in the image of the recording medium is prevented.
|
