Patent ID: 8264508

Claim:
A color image forming apparatus comprising: a plurality of laser beam generating units corresponding to a plurality of colors, each of the laser beam generating units being configured to emit a laser beam based on image data output from an image data generating unit; a data control unit configured to transmit the image data from the image data generating unit to the plurality of laser beam generating units according to a synchronization signal corresponding to each of the laser beam generating units for synchronizing image writing timing in a main scanning direction in image formation; a plurality of photosensitive members configured to have respective electrostatic latent images formed thereon by optical scanning performed by the plurality of laser beam generating units; and a detecting unit configured to read an image of a color misregistration detection pattern for each color formed based on irradiation with a laser beam from the plurality of laser beam generating units and detect an amount of color misregistration, the amount of color misregistration being a relative positional displacement between the colors, wherein the color image forming apparatus is operable in a plurality of operation modes including a first operation mode in which an optical scanning speed is a first scanning speed and a second operation mode in which the optical scanning speed is a second scanning speed different from the first scanning speed, wherein the plurality of laser beam generating units perform scanning in a first scanning direction on a first color and scanning in a second scanning direction on a second color, the first scanning direction being different from the second scanning direction, wherein a delay time due to a delay in transmitting, a signal occurs during a time period from the time when the synchronization signal corresponding to each of the laser beam generating units is output, to the time when the plurality of laser beam generating units receives the image data transmitted by the data control unit, and wherein, in the first and second operation modes, at least one of the plurality of laser beam generating units emits a laser beam with image writing timing for enabling influence of the delay time to be reduced.