| 摘要 |
PURPOSE:To eliminate transfer deviation and the error of image magnification and to improve image quality by controlling the rotating speed of a polygon scanner based on the abrasion rate of a resist roller and the abnormality rate of the rotating speed of a photosensitive drum. CONSTITUTION:At first, a printing engine sequence control part 15 detects a paper conveying state according to the detection timing of the signals S3 and S2 of a resist sensor 14 and a paper position sensor 13 when paper passes. When the abnormality of the abrasion of the resist roller 3 is decided from the signals S3 and S2 inputted in a resist roller abrasion state decision part 15-1, a control part 15 detects the abnormality rate of the rotating speed and inputs it in a polygon correction control decision part 15-2. The control part 15-2 calculates the correction value of the rotating speed of a polygon scanner motor 11 based on the abnormality rate of the rotating speed, the abrasion rate of the roller 3 and the signals S3 and S2, and outputs it to an optical write unit control part 19 to control the rotating speed of the motor 11. Thus, the transfer deviation and the error of the image magnification are eliminated and the image quality is improved, then the life of the roller 3 is prolonged. |
