| 摘要 |
PURPOSE: To reduce the influence of the deviation of an image surface and to excellently adjust printing width by moving only any of Fθlenses plurally constituted to form deflected scanning light into an image at a specified position on a photoreceptor in an optical axis direction. CONSTITUTION: Light emitted from a point light source 1 such as a semiconductor laser is made parallel beams by a collimator lens 2, passes through a cylinder lens 3 and is changed into the light converged only in a subscanning direction so as to be converged on a rotary polygon mirror 4. The light is deflected to perform scanning by the rotation of the mirror 4, and the deflected scanning light is formed into the image at the specified position on the photoreceptor 8 by the Fθlenses 5 and 6. Fine adjusting devices are attached to the Fθlens 6 which is farther from the mirror 4 out of two Fθlenses 5 and 6, the cylinder lens 3 and the collimator lens 2 so as to move them in the optical axis direction. Thus, the influence of the deviation of the image surface caused as soon as the printing width is adjusted is reduced, and the printing width is excellently adjusted.
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