| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical scanner which realizes an excellent optical scanning by attaining the acceleration and high write density of image formation in a tandem type color image forming apparatus. SOLUTION: Each set of a plurality of sets of scanning and imaging optical systems has one or more imaging devices, and an imaging device 8Y provided on the side of an optical deflector 7 and an imaging device 8M belonging to a different set are stacked closely in the axial direction of the optical deflector. When, in the optical deflector 7, the distance in the axial direction of a plurality of luminous fluxes directed to the stacked image forming devices 8Y and 8M is denoted by L, the wavelength of the luminous flux byλ, the distance from a deflection and reflection face to the first face of each scanning and imaging optical device by d1, and the beam spot diameter of a light spot on a plane to be scanned in a subscanning direction by W, then a condition (1) 5×10<SP>-2</SP>≤(λ×d1)/(L×W)≤5×10<SP>-1</SP>is satisfied. COPYRIGHT: (C)2005,JPO&NCIPI |
