Scanning optical apparatus having beam scan controller

摘要

A scanning optical apparatus comprises a light source unit, scanning means for deflecting a beam from said light source unit and scanning a scanning surface with the beam, means for detecting the beam scanned on said scanning surface and control means for controlling the beam scanned on said scanning surface in a direction perpendicular to said scanning surface on the basis of a magnitude and a change as a function of time of a signal output from said detecting means.