Detection and correction method for printing dot area increase values

Abstract

The invention discloses a detection and correction method for printing dot area increase values. A detection strip on which multiple sections of screening step wedges are arranged for each color is attached to each printing sheet; multiple of printing sheets of different time periods are extracted; each color block on the detection strips is detected in a scanning mode, so that the spectral reflectance of each color block is obtained; color difference values of L*a*b*values of green, pinkish red, yellow and black solid color blocks of different ink zones of different printing sheets and standard L*a*b* values are calculated; then simple arithmetic mean values of color differences are calculated; weighted average values of dot areas of screening color blocks of each step wedge of each ink zone of which the color differences are smaller than the average color difference values according to color differences; then the dot area increase values are calculated; and correction values which are needed by digital documents for dot area compensation are calculated according to the average values of dot areas. The dot area increase values obtained in the invention can represent a current dot representation state of a printer more reasonably; dot area correction is performed more correctly; and the detection method is simple for operation and high in efficiency.

Description

technical field [0001] The invention relates to the technical field of quality detection and control in the printing process, in particular to a detection and correction method for dot area increase values ​​of four colors such as cyan, magenta, yellow and black during lithographic printing. Background technique [0002] Lithographic printing uses cyan, magenta, yellow and black four-color dots of different sizes to reproduce the color of the original manuscript through overprinting or juxtaposition. Controlling the dot size is the key to controlling the printing quality. In the printing production process, the viscous ink is coated on the printing plate, and it is attached to the substrate through secondary transfer by using the printing pressure, which usually causes the expansion of the dot area. Generally, the dot area on the substrate is larger than that of the digital file. The dot area corresponding to the above is called the dot area increase in the printing process....

AI Technical Summary

Problems solved by technology

[0004] Aiming at the problem that the detection result of the dot area increase value in the printing process cannot represent the average dot area increase situation under the condition of suitable ink volume, and the compensation and correction of the dot area made is inaccurate, the present invention proposes a printing dot area increase value detection and correction method

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