Patent ID: 6693725
Filing Date: 2004-02-17
Classification: H04N

Abstract:
A multicolor image forming apparatus comprising:a photoconductor; a plurality of laser beam scanners for scanning a plurality of laser beams on a surface of said photoconductor to form a plurality of monochromatic images; a multicolor image forming means for forming a multicolor image on said surface of said photoconductor by overlapping said plurality of monochromatic images; a scanning speed measuring means for measuring scanning speeds of said plurality of laser beams along said surface of said photoconductor; image clock-frequency correcting means for correction image clock frequencies for said plurality of laser beams based on said scanning speeds; and a plurality of laser beam drivers for driving said plurality of laser beams at said image clock frequencies; wherein said photoconductor has a second opening provided near a position in which the laser beam is incident substantially at right angles, a first opening provided on a scanning start side of said second opening, and a third opening provided on a scanning end side of said second opening; and said scanning-speed measuring means has a plurality set of first, second and third opening detectors that detect corresponding laser beams passing through the first, second and third openings.