Scanning optical system

Abstract

In a scanning optical system, which is provided with an imaging optical system having first and second anamorphic optical elements to converge a deflected light beam from a deflector onto an object surface, a power of the first anamorphic optical element in the auxiliary scanning direction varies according to the position in the main scanning direction such that a magnification of the imaging optical system in the auxiliary scanning direction holds constant in any angle of scanning. With this construction, when the exit light beam from the first anamorphic optical element is divergent in the auxiliary scanning direction, the degree of the divergence can be controlled in accordance with the position in the main scanning direction to keep the diameter constant when the light beam enters into the second anamorphic optical element. Moreover, the differential bow can be reduced in the multi-beam scanning optical system.

Dependencies are inferred from the claim text.