Copying machine

摘要

During original document scanning, the forward clutch effects scanning travel of the optics unit in a copying machine having user selectable modes for magnification copying and is normally disengaged by detection of the trailing edge of a transfer sheet being transported through the machine; the return clutch for reverse optics unit travel is simultaneously actuated by detection of the sheet's trailing edge to return the optics unit to its original position. In the event that the trailing edge is not detected before expiration of a predetermined time period corresponding to maximum permissable forward travel of the optics unit for the selected magnification mode, the forward clutch is immediately disengaged, although the return clutch is not engaged until the sheet's trailing edge is subsequently detected.