Antonelli, Terry, Stout & Kraus
Optical scanning apparatus and system
 A small and inexpensive optical scanning apparatus is attained by an optical block 1 disposed between a rotating mirror 2 and a photosensitive body 3 and having specular surfaces formed at part of inner side of surface so that light from the rotating mirror 2 is reflected within the optical block 1 plural times back and forth and reaches the photosensitive body 3 in order to correct the curvature of field, the distortion aberration and the inclination of surface in an optical scanning system. The length of the optical path within the optical block including reflection is set to 60% or more of the whole length of optical path from the rotating mirror 2 to the photosensitive body 3. The surface of the optical block 1 on the side of the photosensitive body is formed into a curved surface to constitute a concave mirror. The rotating mirror and the photosensitive body are arranged in optically conjugate relation in sub-scanning direction by the focal distance. 
Hitachi, Ltd.
G
G02B
inventional
Seiji Yasuaki Yasuro
Maruo Suzuki Hori