Slit exposure optical system

Claim 1

A slit exposure optical system comprising an original holder positioned in a horizontal plane; a copy paper positioned in a plane spaced from said original plane, said copy paper plane being parallel to said original holder plane; said copy paper mounted to be movable at a predetermined speed in said copy paper plane; a photocopying lens is fixed at a location intermediately spaced between said parallel planes; a light source is positioned between said photocopying lens and said original holder so that light from said source provides the reflection of an image in a straight line directly from said original through said photocopying lens; said lens having an optical axis positioned in a plane perpendicular to said parallel planes; a shielding plate fixedly disposed substantially in said copy paper plane and having a slit therein, said slit located adjacent to said optical axis; a reflecting mirror positioned between said lens and said copy paper plane; said reflecting mirror located in a plane parallel to said optical axis plane, one edge of said mirror being movably located adjacent said copy paper plane, the image being reflected onto said mirror in a straight line directly from said lens; said reflecting mirror being movable in the direction of said copy paper movement while being maintained in said parallel relation relation with said optical axis plane; said reflecting mirror being movable at a speed one-half of said predetermined speed of said copy paper so that the image reflected from said original is further reflected from said reflecting mirror and directed in a straight line to be constantly focused by said lens through said slit onto said movable copy paper; and said light source is located on one side of said lens and said reflecting mirror is located to move within a predetermined area on the other side of said lens.