Patent ID: 6185026
Filing Date: 2001-02-06
Classification: G02B

Abstract:
A multi-beam scanning apparatus comprising:a plurality of light sources arranged to be independently driven to modulate light according to an image signal and to emit a plurality of beams;a rotating deflector arranged to receive the plurality of beams emitted from the plurality of light sources and to deflect the beams via a reflective deflecting surface thereof;an image scanning forming lens arranged to receive the deflected beams from the deflector and to condense the deflected beams so as to form optical spots on a scanning surface such that the spots are separated from each other in the sub-scanning direction and such that a plurality of lines on the scanning surface are simultaneously scanned via the optical spots at a substantially constant velocity as the deflector rotates; whereina writing angle corresponding to a writing width of the lines written on the scanned surface is .theta.(rad), a writing density of the dots written on the scanned surface is .delta.(dpi), a maximum difference of wavelength between the plurality of light sources is .DELTA..lambda., and a desired writing width corresponding to the writing angle .theta. with the beam having the desired wavelength .lambda. is L(.lambda.), and the plurality of light sources are such that the value of .DELTA.K, which is defined by .DELTA.K=(1/.theta.)(dL/d.lambda.), and the maximum difference .DELTA..lambda. of the wavelength between the plurality of light sources satisfy the following condition:0<.DELTA..lambda./[25.4.times.2/ {.delta..times..DELTA.K.times..theta.}].ltoreq.1.