| 摘要 |
PURPOSE:To measure the entrance and exit of a dynamic surface which rotates without receiving the effect of a rotational jitter at the time of rotating a scanner motor and to obtain data effective for the evaluation and analysis of a scanner by making a laser light beam incident in parallel with the mirror surface of a polygonal mirror. CONSTITUTION:The diameter of the laser beam L1 emitted from a laser light source 2 is expanded by a beam expander 3 so as to be a specified laser beam diameter W. When the laser beam L2 is in parallel with the surface of the polygonal mirror A, it is made incident on a high speed laser power detector 4. When the entrance and exist of the surface is like A or B, output waveforms respectively become A and B and a difference kd (k means a proportional constant) between their peak values becomes a value proportional to the entrance and exit of the dynamic surface, thereby measuring the entrance and exit of the dynamic surface which occurs during the rotation of the polygonal mirror 1 can be possible. |
