| 摘要 |
PROBLEM TO BE SOLVED: To increase the degree of freedom of the layout of a synchronizing light detecting element. SOLUTION: Luminous flux which is emitted by the light source 1 and coupled by a coupling lens 2 is converged by a cylinder lens 41 in a vertical scanning corresponding direction to form a linear image which is long in a horizontal scanning corresponding direction, the luminous flux is deflected at an equal angular speed by an optical deflector 5 having a deflection reflecting surface 5A nearby the image formation position of the linear image, and the deflected luminous flux is converged as a light spot on the scanned surface 9 to scan a scanned surface at an equal speed with a scanning and image forming lensδ. At this time, this device has a synchronizing light detecting element 7 which detects the deflected luminous flux, which is deflected by the optical deflector 5 and travels to an effective scanning area, as synchronizing light D, an optical element 42 for detection which transmits and guides the synchronizing light D to the synchronizing light detecting element 7 and the cylinder lens 41 are united, and the synchronizing signal which is deflected by the optical deflector 5 is refracted and diffracted by the optical element 42 for detection away from the light source 1. |
