Patent ID: 9081192
Filing Date: 2015-07-14
Classification: G02B

Abstract:
1. An optical scanning device comprising: a light source that includes a string of a plurality of light emitting parts provided with a gap in a main scanning direction of a surface to be scanned, is disposed in plurality in a sub-scanning direction and emits light beams; a light source amount correction unit that corrects an amount of light emitted by the light source based on a portion of detected light; a scanning portion that includes a plurality of reflection surfaces arranged in a circumferential direction with respect to a rotation axis, makes the light beams incident to the reflection surface such that optical axis directions of the light beams emitted from the plurality of light emitting parts are tilted with respect to a direction perpendicular to the reflection surface, and scans the light beams in the main scanning direction through rotation; an optical system that includes an optical member made of a resin, is disposed between the scanning portion and the surface to be scanned, and makes the plurality of light beams incident to the surface to be scanned such that optical axes of the plurality of light beams are parallel to each other; and a correction portion that is provided in the optical system, and corrects positional deviation of scanning lines of the light beams in the sub-scanning direction on the surface to be scanned, wherein the optical system includes the optical member made of a resin in plurality, wherein, in the correction portion, at least three surfaces of entrance surfaces and exit surfaces of the plurality of optical members have curvatures in the sub-scanning direction at positions of the optical axes in the main scanning direction which are different from curvatures in the sub-scanning direction at positions distant from the optical axes in the main scanning direction, and wherein a curvature radius R(y) of at least three surfaces of the entrance surfaces and the exit surfaces is represented by Equation (10) when a surface shape in the main scanning direction at the position of the optical axis in the sub-scanning direction is indicated by Z(y) represented by Equation (8), and a curvature in an X direction, that is, in the sub-scanning direction, is indicated by CUX(y) represented by Equation (9), where CX0 is an integer, and CX1, CX2, CX3, CX4, CX5, CX6, CX7, CX8, CX9, and CX10 are respectively a first order coefficient to a tenth order coefficient