OPTICAL SENSOR AND IMAGE FORMING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an optical sensor capable of measuring smoothness of a recording sheet.SOLUTION: An optical sensor includes a light source, and a light detector that irradiates a recording medium with light emitted from the light source to detect intensity of light reflected on the recording medium. When an incidence angle of the light incident on the recording medium from the light source with respect to a normal of the recording medium is represented as &thetas;1, 75°≤&thetas;1≤85° is satisfied.