LUSTER DETECTOR

A luster detector arranged such that an output light beam of an LED is applied to a surface through a light projecting lens as an irradiating light beam having a predetermined width. Rays of light reflected from the surface are applied through a condenser lens to a line sensor. Of the rays of light reflected from the surface, the rays of light reflected regularly form a light spot on a light detecting section extending in the longitudinal direction of the light detecting section. Hence, even if the light receiving position is shifted, the light detecting operation is positively achieved. A detecting circuit determines the light reception distribution of the sensor to detect the luster of the surface.