| 摘要 |
PROBLEM TO BE SOLVED: To accurately correct the magnification of a latent image in a main scanning direction.SOLUTION: An optical scanner 42 comprises: a light source unit 91; a rotating polygon mirror 94; a photoreceptor 43; first and second light detection units 21 and 22 that output first and second detection signals BD1 and BD2 indicating reception of laser beams; an exposure control unit 11 that performs exposure processing to repeat operation to cause the light source unit 91 to output laser beams corresponding to respective lines during a predetermined reference exposure time on the basis of an output timing of the first detection signal BD1; a time difference measuring unit 12 that performs, at every scanning of the laser beams, time difference measuring processing to measure a time difference between at the time of the output of the first detection signal BD1 and at the time of the output of the second detection signal BD2 corresponding to respective reflection surfaces; and an exposure time correction unit 13 that causes the exposure control unit to perform the exposure processing after the time difference measuring processing is performed, and corrects, when the laser beams are output during the exposure processing, the reference exposure time during the scanning on the basis of the time difference measured corresponding to the reflection surfaces and a predetermined reference time difference. |
