| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical scanner capable of changing light qunatity at a low cost without using any filter. SOLUTION: The main scanning direction beam width of a laser beam 32 made incident upon a polygon mirror 24 is larger than the length of one face 24A of the mirror 24. The laser beam 34 is converted into a weak divergent light through a collimeter lens 14 and then converted into a beam approximately parallel with the main scanning direction through an expert lens 22 and made incident upon the mirror 24. When the lens 22 is moved to the laser diode 12 side, the width of the laser beam 32 made incident upon the lens 22 is narrowed and the main scanning direction width of the laser beam 32 made incident upon the mirror 24 is reduced. Since the center part of the beam 32 has strong energy distribution, the light quantity of a beam made incident upon a photosensitive body can be increased. |
