Defect inspector and method thereof

Abstract

The invention efficiently inspects an uneven-shaped defect and an uneven- concentration defect to reduce a loss caused by excessive inspection. This defect inspecting device of the present invention has the first optical system including the first light source 6 for emitting light toward a surface of an inspected specimen at coaxial falling radiation, and the first image picking-up means 10 for receiving regular reflection light from the inspected specimen to be converted into the first electric signal, the second optical system including the second light source 11 for emitting light toward the inspected specimen at diagonal illumination, and the second image picking-up means 13 for receiving scattered light from the inspected specimen to be converted into and the second electric signal, and a computing means 14 for comparing the first electric signal from the first image picking-up means with the first preset threshold value to detect the uneven-shaped defect on the surface of the inspected specimen, and for comparing the second electric signal from the second image picking-up means with the second preset threshold value to detect the uneven-concentration-of-color defect of the inspected specimen.

Description

technical field [0001] The present invention relates to a defect inspection device and method thereof, and more particularly, to a defect inspection device and method thereof for inspecting the surface of an electrophotographic photoreceptor used in copiers, printers, facsimile machines, and the like. Background technique [0002] The surface of electrophotographic photoreceptors used in copiers, printers, facsimiles, etc. may have defects such as damage, foreign matter, and uneven coating during the manufacturing process. As a method of inspecting such defects, visual inspection is generally performed by inspectors. examine. However, in the visual inspection, variations and the like may occur due to individual differences among inspectors, and therefore, various automatic inspection methods and inspection devices have been proposed instead of the above-mentioned visual inspection. [0003] For example, an inspection device disclosed in JP-A-9-325120 (...

AI Technical Summary

Problems solved by technology

[0004] However, according to the above-mentioned prior art example 1, since the criteria for judging whether the uneven defect and the uneven-shade defect are acceptable or not are different, in an optical system that does not distinguish between the two types of defects for imaging, only defects with stricter criteria can be used. The pass / fail judgment is carried out, so that the products that should be good products may be discarded as non-conforming products, or the non-conforming products judged by the defect inspection device are re-inspected by the inspector

In addition, although the structure is simple, it has the advantage of easy adjustment of the optical system. However, if it is desired to increase the imaging sensitivity of one of the concave-convex defects and the uneven-shade defects, there is a problem that the imaging sensitivity of the other is low.

[0005] According to the above-mentioned prior art examples 2 and 3, although the imaging sensitivity of both the concave-convex defect and the uneven-shade defect can be improved by using several light sources or several CCD cameras, due to the fact that the imaging is performed several times, there is a problem of inspection. long time problem

In addition, if several CCD cameras or light sources are installed relative to one light source or CCD camera, there is a problem of complicated adjustment work.

Images