Patent ID: 7075691

Claim:
A complex lens for a tandem scanning optical system that converges a plurality of light beams, which are modulated independently and deflected by a single deflector, onto a surface to be scanned, to scan a plurality of lines on the surface at the same time, said complex lens comprising: a plurality of stacked lens portions that are molded as a single-piece element, wherein a plurality of lens surfaces of said lens portions at an incident side are formed by a first single-piece mirror surface core and a plurality of lens surfaces of said lens portions at an exit side are formed by a second single-piece mirror surface core during the molding, each of the first and second single-piece mirror surface cores having a plurality of mirror surface portions, the plurality of mirror surface portions of the first single-piece mirror surface core respectively forming a plurality of lens surfaces at the incident side, the plurality of mirror surface portions of the second single-piece mirror surface core respectively forming a plurality of lens surfaces at the exit side, wherein the plurality of lens surfaces on the incident side and on the exit side are configured to be spaced in a direction transverse to a scan direction.