Patent ID: 9261809
Filing Date: 2016-02-16
CPC Classification: G03G

Claim Text:
1. An image forming apparatus in which a plurality of light beams are deflected such that the plurality of light beams scan a photosensitive member, the image forming apparatus comprising: a light source including a plurality of light emitting elements that each emit a light beam; a light power control unit configured to control a light power of light beam that are to be emitted from each of the plurality of light emitting elements; a detection unit, that is provided on a scanning path of the plurality of light beams have been deflected, configured to output a detection signal indicating that a light beam has been detected due to the light beam being incident on the detection unit; a measuring unit configured to control the light source such that first and second light beams emitted 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 that correspond to the first and second light beams and are output from the detection unit; and a timing control unit configured to control relative emission timings of light beams emitted from the plurality of light emitting elements, according to the time interval measured by the measuring unit, wherein the light power control unit is configured to control light powers of the first and second light beams that are to be incident on the detection unit, so as to be a pre-determined light power, the image forming apparatus further comprising: a storage unit configured to store a reference value that is to be a reference for control performed by the timing control unit, and timing values that are determined in association with the reference value and indicate respective emission timings for the plurality of light emitting elements, and a setting unit configured to set a target light power for the plurality of light beams at a time of scanning an image region on the photosensitive member in which an electrostatic latent image is to be formed, wherein the timing control unit is configured to control the relative emission timings for the plurality of light emitting elements using a value obtained by correcting the timing values according to a difference between the time interval measured by the measuring unit and the reference value, the pre-determined light power is set to a light power that is equal to the target light power set by the setting unit, the reference value and the timing values are generated in advance in correspondence with each of a plurality of levels that can be set as the target light power by the setting unit, and are stored in the storage unit, and the timing control unit is configured to use the reference value and the timing values corresponding to the target light power set by the setting unit to control the relative emission timings for the plurality of light emitting elements.