| 主权项 |
1. An image forming apparatus that uses toner to develop an electrostatic latent image that is formed on a photosensitive member by exposing the photosensitive member using a plurality of light beams, and forms an image on a recording medium by transferring a toner image developed on the photosensitive member onto the recording medium, the image forming apparatus comprising:
a light source including a plurality of light emitting elements that each emit a light beam so as to form an electrostatic latent image on the photosensitive member; a rotating polygonal mirror configured to deflect the plurality of light beams emitted from the plurality of light emitting elements such that the plurality of light beams scan the photosensitive member; a detection unit provided on a scanning path of the plurality of light beams deflected by the rotating polygonal mirror, for outputting a detection signal indicating that a light beam has been detected due to the light beam deflected by the rotating polygonal mirror being incident on the detection unit; a speed control unit configured to execute speed change control for accelerating or decelerating a rotation speed of the rotating polygonal mirror toward a target speed, and constant speed control for maintaining the rotation speed at the target speed, the target speed including at least a first rotation speed and a second rotation speed that is different from the first rotation speed, and the first and second rotation speeds being rotation speeds of the rotating polygonal mirror when forming an electrostatic latent image for forming a toner image that is to be transferred onto a recording medium; a measuring unit configured to control the light source such that first and second light beams from first and second light emitting elements among the plurality of light emitting elements are sequentially incident on the detection unit, and to measure a time interval between detection signals generated according to the first and second light beams that are incident on the detection unit in a period of executing the constant speed control for maintaining the rotation speed at the second rotation speed, the period being before or after a period in which the speed change control for changing from the first rotation speed to the second rotation speed is performed by the speed control unit after an electrostatic latent image that corresponds to one recording medium has been formed and being before an electrostatic latent image that corresponds to a recording medium subsequent to the one recording medium is formed; and a control unit configured to, based on the time interval between the detection signals generated according to the first and second light beams that are incident on the detection unit in the period in which the constant speed control is being executed by the speed control unit, control relative emission timings, for the plurality of light emitting elements, of light beams that are based on image data. |
