| 摘要 |
PROBLEM TO BE SOLVED: To decide lighting time of a light source for obtaining a synchronizing signal without causing backside stain of a recording medium, with a simple structure.SOLUTION: An image formation device includes a photoreceptor, a process member acting on the photoreceptor, and an optical scanning device. The optical scanning device includes a light source, a rotating polygon mirror which contains a reflecting surface that deflects optical beam so that the optical beam emitted from the light source scans the photoreceptor, a first signal generating means which receives the optical beam deflected by the reflecting surface and generates BD signal representing a scan start position of the optical beam on the photoreceptor, and a second signal generating means which generates FG signal according to a rotational angle of the rotating polygon mirror. After the rotating polygon mirror is rotated, before applying a voltage for image formation to a process member, a relation between the first signal and the second signal is acquired. After the voltage is applied to the process member, a lighting time of the light source is decided for generating the first signal based on the relation between the first signal and the second signal as well as the number of second signals. |
