| 摘要 |
PURPOSE: A multi-beam optical scanning optical system is provided to obtain a high-definition image at high speed by not needing complicated adjustment but reducing the deviation of the image forming position of a luminous flux from a plurality of light sources effectively. CONSTITUTION: In the multi-beam optical scanning optical system which has a first optical system which converts a plurality of divergent light fluxes emitted from a light source means having a plurality of light sources into a nearly parallel luminous flux or a convergence luminous flux, a second optical system which makes the luminous flux converted into the nearly parallel luminous flux or convergence luminous flux image-form as a linear long luminous flux in a main scanning direction, a deflection means to reflect and deflect a plurality of luminous fluxes in the main scanning direction, a diaphragm to restrict the luminous flux width of the incident luminous flux, and a third optical system which image-forms a plurality of the luminous fluxed reflected and deflected by the deflection means on the surface to be scanned, and sets the deflection surface and the surface to be scanned as the nearly conjugation relation in the sub-scanning cross section, each factor is set so as to satisfy conditional expression wherein (S1*L1)/(f1*f3) is 25.4/4*N1 or less.
|
