OPTICAL SCANNING UNIT AND ELECTROPHOTOGRAPHIC IMAGING DEVICE Russian patent published in 2023 - IPC G02B26/12 

FIELD: laser printing technology.

SUBSTANCE: optical scanning unit comprises a light source configured to emit a light beam; an optical deflector configured to deflect a light beam emitted from the light source; the first optical unit located between the light source and the optical deflector, and the first optical unit includes a refraction unit and a diffraction unit; and a second optical unit disposed in a light exit direction of the optical deflector and configured such that a light beam deflected by the optical deflector forms an image on the scanning target surface. The range of the ratio of the refractive power Ф_r to the diffraction power Ф_d of the first optical block in the direction of the main scan is 0.3<Ф_r/Ф_d<0.5; and the range of the ratio of the refractive power Ф_s to the diffraction power Ф_n of the first optical block in the direction of subscanning is 0.7<Ф_s/Ф_n< 1.0.

EFFECT: invention compensates for the shift in the focus of a light beam caused by a change in the refractive index and wavelength of the optical scanning unit due to temperature changes, thereby improving the quality of image printing.

10 cl, 9 dwg