Scanning lens system

摘要

A scanning lens system forms into an image a deflected beam having its object point in the main scanning direction located at a finite distance to scan a scanned surface. The fourth surface is parallelly decentered in the main scanning direction relative to the optical axis passing the center of a main scanning direction scanning width on the scanned surface. The third and fourth surfaces are rotatively decentered relative to the optical axis about an axis parallel to the sub scanning direction.