Patent ID: 9122190
Filing Date: 2015-09-01
Classification: G03F,G03G

Abstract:
1. An image forming apparatus comprising: a photosensitive member that is driven for rotation; an exposure device that includes a plurality of light sources for emitting a plurality of laser beams, respectively, said plurality of light sources being arranged to expose respective different positions in a sub scanning direction which is a rotational direction of said photosensitive member; an image formation unit configured to form an image by developing an electrostatic latent image formed on said photosensitive member; a first adjustment unit configured to adjust, by changing a phase setting value, a phase relationship between exposure positions of the plurality of laser beams on said photosensitive member, which is a relative positional relationship between an exposure position of a laser beam irradiated from a reference light source of the plurality of light sources in a main scanning direction of the laser beam perpendicular to the sub scanning direction, and an exposure position of a laser beam irradiated from an adjustment target light source other than the reference light source; a second adjustment unit configured to adjust a scanning magnification of the laser beam irradiated from each of the plurality of light sources, by changing a magnification setting value; a first control unit configured to control said exposure device and said image formation unit, such that a plurality of phase adjustment pattern images for adjusting the phase relationship are each formed, using the laser beam irradiated from the reference light source and the laser beam irradiated from the adjustment target light source for which each of phase values different from each other is set as the phase setting value, according to each of the phase values different from each other; and a second control unit configured to control said exposure device and said image formation unit, such that a plurality of magnification adjustment pattern images are each formed, using the laser beam irradiated from the adjustment target light source for which each of magnification values different from each other is set as the magnification setting value, according to each of the magnification values different from each other.