POST POLYGON LENS ASSEMBLY FOR A LASER SCAN SYSTEM
Original Publication Date: 1990-Feb-28
Included in the Prior Art Database: 2004-Apr-05
Xerox Disclosure Journal
In a laser scan system where a modulated laser light beam is directed onto a rotating polygon with mirrored surfaces or facets, the reflected beams are imaged through a post polygon lens system across the full process width of a photosensitive image plane. Typically, the post polygon lens system consists of two spherical lenses with relatively large radii, but also with relatively small clear aperture requirements in the vertical direction. The mounting of these lens in a suitable ROS frame has proved to be difficult because of manufacturing and locational tolerances. One solution is to assemble the lenses on a flat barrel assembly prealigned to functional specifications. Thus, the lenses can be assembled on a metallic plate incorporating functional specifications for the assembly rather than physical dimensions for the elements. Optionally, the lenses may be assembled on the plate as required based on assembly fixturing to compensate for manufacturing tolerance in the individual pieces. The plate can then be mounted in the frame on the same datum structure utilized during alignment (e.g., a plane, a line, and a point).