Patent ID: 9288366
Filing Date: 2016-03-15
CPC Classification: H04N

Claim Text:
1. An optical scanning device for use in an image forming apparatus that forms a full-color image by overlaying a plurality of images each in a different one of solid colors and that has a plurality of photoreceptors disposed in one-to-one correspondence with the solid colors, the optical scanning device comprising: a plurality of high-resolution light source units configured to scan corresponding ones of the photoreceptors in a main scanning direction to form an electrostatic latent image on the corresponding one of the photoreceptors, each individual high-resolution light source of the plurality of high-resolution light sources being operable to emit a set of beams that irradiate one of the corresponding ones of the photoreceptors, each set of beams including at least two beams and the beams of the set of beams of the each individual high-resolution light source are distanced from one another by a predetermined distance along a sub scanning direction orthogonal to the main scanning direction; a deflection unit; a first optical system operable to direct the sets of beams emitted by the respective high-resolution light source units to the deflection unit; a low-resolution light source unit configured to scan a predetermined one of the photoreceptors in the main scanning direction in order to form an electrostatic latent image thereon, the predetermined one of the photoreceptors being one of the corresponding ones of the photoreceptors that is scanned by one of the plurality of high-resolution light sources, the low resolution light source differing from the plurality of high-resolution light sources in that the low-resolution light source is operable to emit a set of beams that irradiate the predetermined one of the photoreceptors and are distanced from one another by a distance larger than the predetermined distance along the sub scanning direction; and a second optical system operable to, after the sets of beams emitted by the respective high-resolution and low-resolution light source units are directed to and deflected by the deflection unit, direct the sets of beams emitted by the respective high-resolution and low-resolution light source units to the corresponding ones of the photoreceptors, wherein the low-resolution light source unit, together with the first optical system, is positioned at one side of the deflection unit so as not to physically interfere with any of the high-resolution light source units and the first optical system, and so as to allow the set of beams emitted by the low-resolution light source unit to, after being deflected by the deflection unit and passing through the second optical system, scan an image forming area on the predetermined one of the photoreceptors along a main scanning direction.