Bottle cap inspection apparatus

摘要

A bottle cap inspection apparatus having a circular shaped light source which is placed to irradiate a cap on a bottle mouth from above; a photoelectric conversion sensor above the cap for receiving the light reflected from the cap; and, an electronic processor for processing an electrical signal from the photoelectric conversion sensor to detect defects in the cap. The bottle is placed under the photoelectric conversion sensor in a manner such that the center axis of the bottle coincides with the optical axis of the photoelectric conversion sensor, and the center of the circular light source coincides with the optical axis. An optical mask is located between the light source and the cap on the bottle mouth such that it defines an outer peripheral surface of a visual field of the photoelectric conversion sensor looking at the bottle mouth as well as an inner peripheral surface of the irradiation range onto the bottle mouth from the circular light source as different conical shapes. A portion of the bottle mouth cap to be inspected is located in a vicinity of the crossing portion of the outer peripheral surface of the conical shaped visual field of the photoelectric conversion sensor with the inner peripheral surface of the irradiation range of the circular light source.