An image-based method for detecting registration errors of printing varnish

Abstract

The invention relates to a method for detecting registration errors of printing gloss oil based on an image. The method comprises the following steps: (S1) printing a bottom color mark on any type ofprinted material, printing a printing gloss oil mark on the bottom color mark, wherein the color of the bottom color mark is a color system capable of respectively generating gray difference with thecolor of the printed material and the color of the printing gloss oil mark after imaging; (S2) selecting a blue coaxial light source for lighting, photographing a region of the bottom color mark, andacquiring the photographed image; and (S3) analyzing an image so as to obtain the relative distance from the bottom color mark to the printing gloss oil mark, and detecting the registration error between the bottom color mark and the printing gloss oil mark. Compared with a traditional method, the method has the advantages that the detection precision is high, and the registration errors of printing gloss oil can be directly detected.

Description

technical field [0001] The invention relates to the field of printing, in particular to an image-based method for detecting registration errors of printing varnish. Background technique [0002] Printing varnish is a kind of synthetic resin. It usually refers to the surface transparent varnish. It is made of base materials and additives. It does not add any pigments. As a transparent protective varnish, its hardness and wear resistance are better than those of color varnishes, and it plays a protective role; printing varnish is a colorless and transparent medium, and its direct imaging effect is extremely poor. The overprint alignment technology adopted by the printing machine needs to detect the registration error of the printing varnish to determine the position of the printing varnish when the printing varnish is overprinted; in the prior art, the photoelectric method is used for detection, The traditional photoelectric method uses a photoelectric head to detect the easi...

AI Technical Summary

Problems solved by technology

The overprint alignment technology adopted by the printing machine needs to detect the registration error of the printing varnish to determine the position of the printing varnish when the printing varnish is overprinted; in the prior art, the photoelectric method is used for detection, The traditional photoelectric method is to use the photoelectric head to detect the easily visible mark on the printing material, which is phase-locked with the varnish printing roller. It is an indirect detection method, and the detection error is relatively large.

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