Single pass color printer

Claim 1

An imaging system for forming multiple image exposure frames on a photoconductive belt moving in a process direction during a single pass, the imaging system comprising: a plurality of Raster Output Scanners (ROS) units, each ROS unit generating image-modulated scan lines which are transmitted along an optical path to form said image exposure flames, said ROS units located in a comon housing and positioned symmetrically on opposite sides of two polygon scanners mounted vertically on a common rotating shaft, said ROS units each comprising: a diode laser for generating a beam output; means for modulating the beam output of said laser with input video data; optical means for collimating and expanding the modulated laser beam output and directing the collimated and expanded output against an associated polygon scanner; post polygon lens group for correcting for fθ distortion in the reflected beam thereby producing a corrected scanning beam; a 90° roof mirror assembly mounted on a movable mirror carriage which folds the corrected scanning beam from the post polygon lens group in a 180° path reversal, said mirror carriage having a ferrous mating surface; a folding mirror for directing the corrected scanning beam out of the common housing and onto the photoreceptor belt, each scanning beam being parallel to each other; a focus carriage secured to the ROS housing at a position providing an optically focused scan line at the photoreceptor surface, said focus carriage having a ferrous mating surface; a guide assembly connected to said mirror carriage and to said focus carriage, said guide assembly including a guide system which provides a slight degree of skew and process correction motion to said mirror carriage relative to said focus carriage, said guide system comprising a plurality of magnets affixed to said mirror carriage, said magnets being in magnetic contact with said ferrous mating surface during correction motion.