| 摘要 |
PURPOSE:To simplify assembling work by reducing the number of parts of a substrate for attaching a laser diode and a horizontal synchronization detecting sensor. CONSTITUTION:In this device, a laser beam projected from a laser diode 15 is reflected in a main scanning direction over a specified angle by a polygon mirror 14 rotating at high speed. The laser beam is reflected by a plane mirror in front of a main scanning range, and received by the horizontal synchronization detecting sensor 30 so as to generate a horizontal synchronizing signal which is reference for deciding the starting phase of the main scanning range. The laser diode 15 and the sensor 30 are arranged adjacently to each other and attached to the same substrate 16 so that the 1st optical axis LB of the laser beam projected from the laser diode 15 is positioned on the angle-of-delay side in the rotating direction of the mirror 14 with respect to the 2nd optical axis LBR of the laser beam entering the sensor 30 from the mirror 14. |
