Patent ID: 6191803
Filing Date: 2001-02-20
Classification: B41J,G02B

Abstract:
A multiple light beam scanning optical system comprising:a plurality of light sources;driving circuits for independently driving said plurality of light sources;a plurality of collimator lenses for collimating light beams from said plurality of light sources to provide a plurality of substantially parallel light beams, respectively;a plurality of cylindrical lenses for focusing respective light beams emitted from said plurality of collimator lenses only in a sub-scanning direction;a beam splitter for making optical axes of light beams emitted from said cylindrical lenses coincident with each other;a deflector having a deflection surface near a point at which the light beams emitted from said beam splitter are focused by said cylindrical lenses;a scanning lens for scanning the light beams deflected by said deflector on a scanned surface;a synchronizing detector for detecting whether or not said light beams are synchronized with each other when the light beams are respectively scanned on said surface;a sensor unit for detecting position information of the sub-scanning direction of said light beams at a position substantially equivalent to said deflector from a light beam emitted in a direction different from a direction that said beams travel from said beam splitter to said deflection surface;a control circuit for driving and controlling at least one of said cylindrical lenses by processing an output signal from said sensor unit; anda light path correction mechanism for moving said at least one of said cylindrical lenses on the basis of a control signal from said control circuit, wherein:said control circuit controls said light path correction mechanism such that said light path correction mechanism causes positions of said light beams to coincide with each other in response to said position information of the sub-scanning direction of said light beams sensed by said sensor unit and moves ones of said light beams in a sub-scanning direction thereof relative to a particular one of said light beams.