| 摘要 |
PROBLEM TO BE SOLVED: To provide a focus confirming jig of a copying machine for which conditions of a light source and an image forming plane are equivalent to that of actual copying operation, capable of highly precise confirmation of focus without difficult adjusting work and coping with a photoreceptor drum of a small diameter. SOLUTION: A light projection jig is provided with a point light source composed of a halogen lamp 6 installed over a test chart 2, a light condensing plate 5, a diffusing plate 3 installed between the point light source and the test chart and a cooling fun. A light receiving jig is provided with a diffusion processing part and its supporting part installed on a curved surface having circular shaped cross section along the outer surface of the photosensitive drum and a reflection part for guiding a light beam transmitted through the diffusion processing part to the light receiving part of a CCD camera. Since an image is formed by the diffusion processing part located at the position of outer diameter of the photosensitive drum and the image is indirectly observed by the CCD camera, the confirmation of focus is performed on the same condition as the actual case. By installing the CCD camera in parallel with the axis of the photoreceptor drum, it is possible to cope with a photoreceptor drum of a small diameter. |
