| 摘要 |
PURPOSE:To eliminate a detection error due to the difference in size of patterns and to simplify control, by rendering same the positions, shapes, and sizes of the patterns to be formed on a photoreceptor. CONSTITUTION:A sensor pattern 2 has a size of 20mm. in the direction parallel to the axis of a photosensitive drum 8 and 28mm. in its peripheral direction, and when contraction copying is carried out in a magnification of 0.65, a lens 7 is moved toward the drum 8, and the projected image of the pattern 2 on the drum 8 is contracted from an image 15 having 20mm. width at a magnification of 1 to an image 16 having 13mm. width. On the other hand, as for the peripheral direction of the drum 8, the peripheral drum speed is raised from 120mm./sec at a magnification of 1 to 185mm./sec, and the projected image is contracted from 28mm. length of the image 15 to 18mm. length of the image 16. The image 15 is shown by full lines and the image 16 with chain lines, and when it is developed as it is, the difference in pattern size occurs and causes detection errors, so the range hatched (13mm.X13mm.) is set as an image forming range, and its outside parts are destaticized with an eraser 10 to eliminate the difference of the patterns and detection errors. |
