| 摘要 |
PROBLEM TO BE SOLVED: To easily adjust the pitches of two laser luminous fluxes in a subscanning direction. SOLUTION: A collimator lens 12, a cylindrical lens 13, and a polygon mirror 14 are successively arranged on the optical axes of the laser luminous fluxes L1 and L2 emitted from a two-beam laser unit 11, and a toric lens 15, an fθlens 16, a bending mirror 17 and a photoreceptor drum 18 are successively arranged in the reflection direction of the laser luminous fluxes L1 and L2 by the polygon mirror 14. Furthermore, a turning means, not shown in figure, which turns the lens 13 by a very small quantity centering around an x-axis passing the centers of the laser luminous fluxes L1 and L2 is coupled with the lens 13. When the lens 13 is turned by the turning means, the pitch of two laser luminous fluxes L1 and L2 emitted from the lens 13 is changed and the pitch (d) of scanning lines S1 and S2 formed on the drum 18 is also changed.
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