Secondary offset printing method to achieve roll-to-roll high-precision registration

Abstract

The invention discloses a secondary offset printing method for realizing roll-to-roll high-precision registration, which firstly calculates the deformation amount of the roll paper under the action of the tension of rewinding and unwinding, and then calculates the circumferential size of the imposition plate on the printing surface of the roll paper , and formulate the production imposition process; then form a positioning pattern on the film surface of the positioning transfer film, and make a finished roll paper, and form a positioning mark every week; then use the positioning mark to plate the finished roll paper Weekly error pre-checking; printing and hot stamping are carried out at the end, and the longitudinal offset is continuously adjusted by detecting the position of the color mark and the degree of color difference during the printing process, so that the paper accuracy during the printing process can reach ±0.2mm, and the printing accuracy can reach ±0.1 mm; so as to ensure stable positioning and overprinting and exquisite pictures in the printing process, greatly reduce the reject rate during high-precision secondary printing, greatly improve printing efficiency, and have broad application prospects.

Description

technical field [0001] The invention relates to the field of web printing, in particular to a secondary offset printing method for realizing roll-to-roll high-precision registration. Background technique [0002] With the improvement of living standards, the current packaging boxes have higher and higher requirements for the exquisite printing effect. In addition, due to the continuous advancement of science and technology, it is also necessary to continuously update anti-counterfeiting methods to identify counterfeit products. In order to achieve better visual Effect and anti-counterfeiting effect, sometimes it is necessary to use a positioning transfer film with a positioning pattern on the film surface, transfer the positioning transfer film to the printing paper, and then perform secondary printing and bronzing on the positioning pattern area on the film surface, thereby greatly improving the printing pattern. Texture; at the same time, because the pattern is extremely d...

AI Technical Summary

Problems solved by technology

Since the boundary line will be printed on the edge of the positioning pattern area during the second printing, the printed boundary line must be highly coincident with the edge of the positioning pattern area. It is also required that the bronzing pattern must be located in the pattern area during bronzing. Therefore, in the secondary printing Both printing and hot stamping require high registration accuracy, so that both the printed pattern and the hot stamping pattern are accurately registered with the positioning pattern area on the film surface, and the positioning transfer film is prone to misalignment during printing and hot stamping due to its smooth surface. shift

[0003] Since the positioning transfer film is easily shifted during the unwinding process, and the tension generated by web printing during printing will also deform the paper, it is difficult to achieve high precision. In addition, because the web is printing Errors will continue to add up during the process. When the errors continue to accumulate, it will easily lead to a large number of waste products. Therefore, paper with positioning transfer film is generally not printed on roll paper.

Although there is no tension and error accumulation in the sheet-fed printing method, offsets may still occur due to the paper accuracy of sheet-fed printing (that is, the distance between the center points of two adjacent product patterns in the longitudinal direction) Fluctuation range) is generally ±0.5mm, and printing accuracy (that is, the fluctuation range when different color groups are printed at the same position) is generally ±0.3mm, which will also produce a high reject rate, and the sheet-fed printing efficiency is relatively low. Low, not suitable for mass production

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