| 摘要 |
PURPOSE:To obtain a wide monitoring area without illuminance irregularity on a cylindrical surface thereby to make inspection easy by so arranging that an area to be inspected on the outer peripheral surface of a photosensitive drum is radiated with a light of a cylindrical wave agreed with the curvature of the area. CONSTITUTION:A light projected from a light source 7 is turned to a plane wave through a front group of beam expanders 8, a half mirror 9, a rear group of beam expander 10. A cylindrical wave is formed in a cylindrical optical system 11 which has the curvature agreed with that of the outer peripheral surface of a photosensitive drum 1. The drum 1 is preliminarily placed at a position where the curvature of the outer peripheral surface thereof is agreed with the curvature of the cylindrical wave. Therefore, the radiating area of the cylindrical wave at the outer peripheral surface of the drum 1 has no illuminance irregularity. In the subsequent image forming process, a reflecting light from the peripheral surface of the drum 1 forms an image to an area image sensor 13 through the optical system 11, rear group of expanders 10, mirror 9 and optical system 12. In this manner, the outer peripheral surface of the drum 1 can be illuminated uniformly in the radiating area, and therefore, it is possible to secure the monitoring area relatively wide. |
