| 摘要 |
PROBLEM TO BE SOLVED: To scan plural beams by a cylinder lens, a rotary polygon mirror, and an Fθlens whose dimensions are approximately equal to those for scanning one beam. SOLUTION: The optical scanner is provided With first and second lenses 3 and 4 between a collimator lens 2 and a rotary polygon mirror 6 and is constituted so as to satisfy conditions J=C+(C<2> /B)-(C<2> G/B<2> ) and C=BE/D where B, C, D, E, G, and J are the focal length of the first lens, that of the second lens, the beam diameter in the collimator lens, that in the second lens, the distance between the crossing position of plural beams in the vicinity of the collimator lens and the first lens, and the distance between the second lens and the rotary polygon mirror respectively. |
