Method and means for preventing edge shadow effects during episcopic exposure of an original

摘要

Edge shadow effects on copies obtained by episcopic exposure of an original lying on a transparent exposure plate are prevented by directing light toward at least one side edge of the original from a surface laterally adjacent thereto of a light transmitting means disposed on the exposure plate. Each light transmitting means is constituted by a transparent plate member having its surfaces made diffusely reflecting, except a transparent surface directed toward the original and a transparent surface disposed in a path of illumination from a light source. Such a plate member extending along a margin of the exposure plate in electrophotographic copying apparatus serves the dual function of guiding the laying of an original onto the exposure plate and preventing edge shadow effects which otherwise result from a narrow slit or cavity that usually occurs between an edge of the original and the guide member usually provided on the exposure plate.