Color image forming apparatus and system

摘要

A color image forming apparatus for forming a color image on a recording medium, includes: an image carrier; a polygon mirror; a signal forming device for forming a pseudo main scanning reference signal having a fixed cycle; and a controller for controlling image formation on a predetermined surface of the recording medium on the basis of the pseudo main scanning reference signal formed by the signal forming device and a main scanning reference signal which is formed by detecting a light beam that is scanned by the polygon mirror.