Patent ID: 7564473

Claim:
An image forming apparatus, comprising: a latent image carrier which is freely rotatable in a predetermined sub scanning direction; a latent image carrier gear which is attached to an end portion of the latent image carrier; a drive motor which applies drive rotation force upon the latent image carrier via the latent image carrier gear and which rotates the latent image carrier; a line head which forms on the latent image carrier a line latent image which extends in a main scanning direction which is approximately orthogonal to the sub scanning direction; an exposure controller which provides an image signal to the line head and controls writing of the line latent image; a phase detector which detects phase data regarding the latent image carrier gear; and a timing controller which adjusts the write location of the line latent image on the latent image carrier based on the phase data detected by the phase detector, wherein the line head includes multiple light emitting elements which are arranged in rows along the main scanning direction, and every time the line head holds an image signal representing one line corresponding to the multiple light emitting elements from the exposure controller, the multiple light emitting elements are driven approximately simultaneously based on the image signal, the timing controller provides the exposure controller with a synchronization signal, thereby controlling the timing at which the exposure controller outputs the image signal, provides the line head with a strobe signal, thereby controlling the timing at which the multiple light emitting elements emit light, and corrects the cycles of the synchronization signal or the cycles of the strobe signal based on the phase data detected by the phase detector, thereby adjusting the write location of the line latent image on the latent image carrier, and the timing controller outputs the strobe signal at the timing that the line head holds the image signal representing one line, while correcting the cycles of the synchronization signal based on the phase data detected by the phase detector, thereby adjusting the write location of the line latent image on the latent image carrier; the image forming apparatus further comprising a memory which stores a correction table in which various phase data are correlated to corrected values of the cycles of the synchronization signal, wherein the timing controller reads from the correction table a corrected value of the cycles corresponding to the phase data detected by the phase detector, and the exposure controller outputs the image signal in synchronization to the synchronization signal whose cycles have thus been corrected.