| 摘要 |
An image forming apparatus uses a beam detector (BD) sensor (207, Fig.2A) to measure a time interval between light beams emitted from two light emitting elements in a period during which constant speed control for maintaining the rotation speed of a polygon mirror at a target speed is performed and speed change control for accelerating or decelerating the rotation speed toward the target speed is not performed (S619, Fig.6B). Based on the time interval between BD signals generated according to the two light beams that are incident on the BD sensor while the constant speed control is being executed, the image forming apparatus controls the emission timings of the light beams that are based on the image data for the light emitting elements (S622, S620, Fig.6B). |
