Optical scan apparatus having jitter amount measuring means

摘要

A scan optical apparatus is provided with a first light source for generating a beam for scan optically modulated based on an image signal, a second light source for generating a beam for jitter amount detection, a scanning device for deflecting the beams from the first light source and from the second light source to scan a surface to be scanned, an optical member disposed in the vicinity of the surface to be scanned or at a position substantially optically equivalent to the surface to be scanned, and a detecting device for detecting a beam reflected by the optical member and deflected by the scanning device. The optical member may have reflective portions and nonreflective portions which are repeatedly arranged in a main scan direction, or may be a corner cube array in which a plurality of corner cubes are arranged in the main scan direction. Further, the surface to be scanned may be a recording medium in a recording apparatus.