| 摘要 |
<P>PROBLEM TO BE SOLVED: To make the configuration simple and inexpensive, when using several beams for scanning in the so-called "oblique-incidence method" to the optical deflector and the first lens optical system in a scanning optical system, an optical scanner that uses it, and an image forming device. <P>SOLUTION: This scanning optical system irradiates a laser beam 30D, from the beam light source 5D to a polygon mirror 8 oblique with respect to the surface, perpendicularly crossing its rotation axis, to deflect and to be obliquely incident to the first lens 11 in the secondary scanning direction, and radiates the laser beam 30D, made to exit from the first lens 11 to the second lens 12 to apply beam scanning. The first lens 11 has at least two free curved surfaces, and the first lens 11 and the second lens 12 are in a positional relation such that the light flux exited from the first lens 11 forms the scanning locus straddling the center line, extending in the main scanning direction on the first surface and on the second surface 12b of the second lens 12. <P>COPYRIGHT: (C)2007,JPO&INPIT |
