| 摘要 |
PROBLEM TO BE SOLVED: To promote the reducing of the cost of a device by improving compactness. SOLUTION: This device is constituted so that the optical scanning of a constant velocity of a surface to be scanned 24 is performed by deflecting the luminous flux from a light source 10 in a constant angular velocity by the optical deflector 20 having deflecting reflection planes 21 and by converging the deflected luminous flux on the plane to be scanned 24 as an optical spot by an image-forming lens 22. In this case, moreover, the device has a synchronization detecting part 32 detecting the deflected luminous flux deflected by the optical deflector 20 prior to an optical scanning and a synchronous lens 28 guiding the deflected luminous flux to the synchronization detecting part 32 in order to obtain the shnchronizing signal defining write positions in the optical scanning. Then, the housing holding an optical system is miniaturized by refracting the light path of the luminous flux from the light source 10 by the first reflection plane 18 to make it incident on the deflecting reflection planes 21 of the optical deflector 20 and also by reflecting the light path of the deflected luminous flux outgoing to the synchronization detection part 32 via the synchronous lens 28 in between the deflecting reflecting planes 21 and the synchronization detecting part 32 by a second reflection plane 26. |
