Inspection device for article being inspected, spark plug inspection method, and method for manufacturing spark plug

摘要

A spark plug is held by a work holder, and an illumination device is disposed between a rear end surface of a metal terminal of the spark plug and a lens of a CCD camera. The positional relationship among the rear end surface, the lens and a light source is determined such that regular reflected light resulting from regular reflection of irradiation light emitted from the light source and impinging on the rear end surface is not incident on the lens. In capturing an image of the rear end surface not only is the regular reflected light not incident on the lens, but also the incidence, on the lens of irregular reflected light resulting from irregularities on the rear end surface is reduced, whereby interference of reflected light with a captured image can be reduced.

主权项

1. A device for inspecting an identification mark formed on a surface of an inspection object, said surface being made of metal, comprising:
a camera that captures an image of the inspection object surface in an image capturing direction orthogonal to the inspection object surface; a work holder that holds the inspection object such that a predetermined distance along the image capturing direction is established between the camera and the inspection object surface; an illuminator that has a light source, adapted to illuminate the inspection object surface with irradiation light emitted from the light source, and disposed at a position which is located between the inspection object surface and the camera with respect to the image capturing direction such that reflected light resulting from regular reflection of the irradiation light impinging on the inspection object surface is not incident on the camera; an image processor that processes an image captured by the camera, and acquires characteristic information of the identification mark from an image of the identification mark in the captured image; a storage device configured to execute a program that compares the characteristic information of the identification mark and characteristic information of a reference mark acquired beforehand from an image of the reference mark, and judges whether or not the identification mark and the reference mark are the same mark, the inspection object surface has a maximum diameter or diagonal length of 10 mm or less, and the illuminator is configured such that the light source has an annular shape, whose inside diameter is 10 mm or more.