Patent ID: 9696674
Date: 2017-07-04
CPC Classifications: G03G

Claim:
1. An optical sensor comprising: a light source; an optical detector configured to detect intensity of light that is reflected by a recording medium, the light emitted from the light source and irradiated onto the recording medium; a controller configured to calculate a smoothness of the recording medium based on the intensity of the light detected by the optical detector; and one or more lens disposed between the recording medium and the optical detector, such that a light receiving surface of the optical detector is disposed at a focal position of the one or more lens, and an incident angle θ wherein an incident angular width of the light incident to the optical detector due to the lens is less than or equal to 10°, and wherein the incident angular width depends on an area of a light receiving surface of the optical detector and a focal length of the lens disposed between the recording medium and the optical detector.