| 摘要 |
PURPOSE:To facilitate the adjustment of an image formation position in the direction orthogonal to the lengthwise direction of a slit in a plane orthogonal to an optical axis, by providing a plane-plate transparent body, which has a thickness across the optical path of a luminous flux, rotatably with a shaft parallel with the length wise direction of the slit as the center and turning this plane-plate transparent body. CONSTITUTION:A plane-plate transparent body 10 which has a thickness across the optical path between the fourth mirror 8 of an exposure optical system and the image formation position on a photosensitive drum 9 is so-provided that it can be rotated around a shaft 12 parallel with the lengthwise direction of the slit. The shaft 12 is supported axially by both side plates of the device; and a knob attached to one side plate is turned with a finger to change the angle of crossing between the plane-plate transparent body 10 and the optical axis, thereby moving the image formation position on the photosensitive drum 9 in the direction orthogonal to the slit. |
