| 摘要 |
An image forming apparatus includes: a plurality of optical systems, each of which includes a light-beam generating unit that generates a light beam, a rotary polygon mirror that deflects the light beam so as to scan a image carrier, and a light-beam detecting unit that detects the light beam deflected for scanning at a predetermined position on a scanning path by rotationally driving the rotary polygon mirror; a time-difference measuring unit that measures a time difference between light-beam detecting signals; a generation-timing determining unit that determines time of generation timing for generating a start signal that designates a start of an image writing operation so that the generation timing does not overlap another timing when each of the light-beam detecting signals is output from the corresponding time-difference measuring unit; and a start-signal generating unit that generates the start signal based on the time for the generation timing. |
