US Patent 7777774 Image forming system employing effective optical scan-line control device

An optical scanning characteristic control method is applied to an optical scanning system in which a beam is deflected, and the deflected beam is converged and directed toward a scanning surface, so that optical scanning of the scanning surface is performed by an optical spot formed thereon by the deflected beam. The method comprising the steps of a) disposing a beam deflection control device on the light path of the beam before it is incident on the scanning surface; and b) controlling a beam deflection amount of the beam deflecting device provide to an incident beam so as to control a scanning characteristic of the optical scanning.