| 摘要 |
PURPOSE:To eliminate a need of position adjustment of a photodetector and reduce the cost by detecting the output of a fluorescent optical fiber arranged approximately perpendicularly to the light beam scanning direction by the photodetector to detect the position of the light beam. CONSTITUTION:The light beam radiated from a light source 1 like a semiconduc tor laser irradiates an irradiated part like a photosensitive drum 3 through a scanning part consisting of a rotating mirror 2, etc. A columnar fluorescent optical fiber 11 is arranged in a prescribed position in the plane, which is formed with the light beam scanned by the scanning part, perpendicularly to this plane, and the fluorescent optical fiber 11 has fluorescent materials internally, and these materials emit fluorescence when the light beam irradiates, and this fluores cence is received by a photodetector 12 arranged on the end face of the fluores cent optical fiber. Consequently, the fluorescent optical fiber 11 is irradiated with the light beam regardless of inclination of the rotating mirror 2. Thus, the cost is not increased and it is unnecessary to adjust the position of the photodetector. |
