Greenblum & Bernstein, P.L.C.
Multi-beam scanning optical system
 A multi-beam scanning optical system is provided with a light source unit emitting a plurality of beams. The beams are incident on a polygonal mirror, and deflected thereby to scan in a predetermined scanning range. The scanning beam is incident an f.theta. lens system. The f.theta. lens system includes a plurality of lenses, and all the beams pass at least one of the plurality of lenses included in the f.theta. lens system. The lens, which all the beams pass through, is formed as a single lens element made of single material. Further, the lens contributes to convergence of the beams in the main scanning direction. 
Asahi Kogaku Kogyo Kabushiki Kaisha
B G H
B41J G02B H04N
inventional inventional inventional
Yoshihiro Yasushi Susumu
Hama Suzuki Mikajiri