Patent ID: 9420119
Filing Date: 2016-08-16
CPC Classification: G01J,H04N

Claim Text:
1. A scanning optical system manufacturing method comprising: receiving a scanning beam, emitted from a scanning unit including an incident optical system and a deflecting device and passed through an image-forming optical system, in an area having a light-receiving width in a main scanning direction narrower than a spot diameter of the scanning beam by a light-receiving unit configured to be capable of being displaced at each image height position in the main scanning direction; calculating, based on an output of the light-receiving unit, a peak light quantity at each image height position of the scanning beam; smoothing, using an evaluation width in the main scanning direction, distribution data of the peak light quantity at each image height position acquired by the calculating; and determining, based on the data acquired by the smoothing, either nondefective/defective states of the scanning unit and the image-forming optical system or a nondefective/defective state of only the image-forming optical system, wherein the evaluation width is equal to or less than a shift amount of the scanning beam on an image surface of the image-forming optical system in the main scanning direction when the scanning beam from the deflecting device shifted as much as a width of the scanning beam at an optical surface of the image-forming optical system in the main scanning direction.