| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce the cost of a scanning lens, reduce the size of an optical housing due to optimum layout, and hence the entire image forming apparatus that uses the optical housing, further, to obtain satisfactory image quality by reducing the diameter of a sub-scanning beam spot and deviation between the image heights of the sub-scanning beam pitch, and to obtain satisfactory image quality. <P>SOLUTION: An optical scanner has: two light sources corresponding to different surfaces to be scanned; an optical deflector for deflecting luminous fluxes from the two light sources; and two scanning lenses for focusing the luminous fluxes from the two light sources deflected by the optical deflector on respective corresponding surfaces to be scanned. The luminous fluxes from the two light sources are made incident on at an angle in a sub-scanning direction with respect to a normal line of the deflecting reflection surface of the optical scanner, and are deflected and reflected by the same deflecting reflection surface of the light deflector. The two scanning lenses are shared by all luminous fluxes from the two light sources. At least two surfaces thereof are sub-scanning curvature change surfaces on which the curvature in the sub-scanning direction changes according to a main scanning position. <P>COPYRIGHT: (C)2012,JPO&INPIT |
