Abstract: A rotatable "Y" scan mirror for a flat field scanning system is provided whereby the mirror is shifted in opposite directions transverse to its pivotable axis and is simultaneously rotated in one direction during a scanning cycle. A pair of cams is mounted on a common rotatable shaft for rotation therewith. One of the cams actuates a link connected to a pivot pin on which the mirror rotates. The other cam actuates an arm which is connected to the mirror to rotate the same. The cams are so designed to cause shifting of the mirror to maintain a constant length optical path to the medium being scanned and to cause rotation of the mirror in such a manner that the rate of scanning across the medium will be constant.

Abstract: A three-fold mirror array for a scanning projection system to permit placing the object and image of an annular reflective projection system in an orientation which facilitates scanning and yields an image symmetry identical to that obtained with contact printing in which three folding flats are combined with an annular field projection system. The three folding flats are incorporated in a monolithic assembly having a 90.degree. groove on one side and a fold surface perpendicular to the other folding surfaces on the other side of the assembly thereby permitting a simple pivoting scanning mechanism to be used for scanning a field larger than the narrow annular field available in the projection system.