| 摘要 |
PURPOSE:To facilitate manufacture and to attain variable power with a little aberration and a little astigmatism without decreasing resolving power by using plural triangular prisms consisting of planes. CONSTITUTION:A moving original is lighted by a lighting device 12 and its image is transmitted to a photosensitive body 4 through a mirror 13, projection lens 14, mirror 15, and prism 10'. The projection lens 14 is movable to an indicated magnification position and the speed ratio of a scanning system and a photosensitive body 4 and the position of the projection lens 14 are so set that slit lengthwise magnification and slit breadthwise magnification are different from each other. Then, plural prism systems 10' which have refracting power not in the slit lengthwise direction, but in the slit breadthwise direction are so provided that the speed of the projected image of the original is equal to the speed of a photosensitive body. Thus, those plural prisms 10A and 10B are used to attain the anamorphic variable power of a sharp image with small image inclination, a little astigmatism, and a little chromatic aberration. |
