Patent ID: 7372604
Filing Date: 2008-05-13
Classification: B41J,G02B,Y10S

Abstract:
1. A multi-beam scanner, comprising: a plurality of light sources configured to emit beams independently modulated according to an image signal, respectively; a deflector having a deflecting/reflecting face and configured to deflect the beams emitted from the plurality of light sources at an equiangular velocity; a scanning image-forming optical system configured to guide the beams deflected by the deflector to a scanned surface so as to be formed into a plurality of light spots on the scanned surface; a light receiving device configured to sequentially and individually receive the beams deflected toward optical write-in starting portions on the scanned surface as synchronizing beams, the light receiving device being common to the synchronizing beams; and a synchronizing beam optical system that guides the beams deflected to the optical write-in starting portions to the light receiving device, the scanning image-forming optical system having at least one scanning lens, the synchronizing beam optical system including at least one of the at least one scanning lens and a refracting optical element, each deflected beam to be received by the light receiving device passing through the at least one of the at least one scanning lens and a principal ray of the deflected beam passed through the scanning lens being deflected by the refracting optical element so as to be guided to the light receiving device, and a shift, due to a difference in wavelength of the deflected beam, of an incidence position on the light receiving device of the deflected beam in a synchronizing beam detecting angle being reduced by a difference in a refracting action of the refracting optical element due to the deflected beam wavelength difference.