Discussion on water ink printing technology of the

2022-08-11
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With the development of social economy and the improvement of national living standards, people pay more and more attention to the perfection of commodity packaging. Corrugated box packaging with its unique functions in the entire goods packaging industry also accounts for an increasing proportion, and the key technology of corrugated box is ink printing. This article talks about how to use equipment improvement to improve the quality of hydration and pre ink printing

1 treatment of printing white spots

printing white spots are the most common and difficult quality problems in the production of corrugated boxes, and their causes are: ① poor ink absorption performance of paper; ② The offset is dirty; ③ There are scraps of paper, dust, etc. on the cardboard. The traditional treatment of these problems is to manually change the box and increase the frequency of manual erasure. These methods will play a certain role objectively. However, after changing the box, the effect is not improved much, and the efficiency is reduced. Wiping glue also causes waste of water, electricity and labor

after long-term observation and analysis in the process of equipment installation, maintenance and management, I believe that the key to causing white spots in printing is dust removal, and the main source of dust is generated during single knife separation. Based on this situation, two years ago, I installed electrostatic dust collection devices in the back end of the computer crosscutting knife of the cardboard production line and the paper feeding Department of the printing machine. Use a hair dryer in front of the computer cross cutting knife to blow out or blow away the paper fragments hidden in the pit pattern when the single-chip knife separates the paper, and then use the electrostatic dust collector to suck away the paper fragments with a large amount of oil from the oil return pipe of the oil feeding valve at the paper receiving rack behind the computer cross cutting knife. At the gap between the paper feeding rubber ring and the paper feeding wheel in the paper feeding section of the printing machine, electrostatic dust collection is used to absorb the dust on the paperboard, so as to keep the printing surface clean and dust-free, so that when the product enters the printing roller, there is no obstacle to inking, and the ink absorption checks whether the deformation sensor selection and curve display coordinates of the experimental scheme are correct and uniform

after such improvement, the printing effect of the product is significantly improved, and the phenomenon of white spots caused by dust is fundamentally prevented

2 handling of overprint displacement

now commodity packaging pays more and more attention to the artistry and three-dimensional sense of the pattern, so that consumers can feel the perfection of the purchased goods from the outer packaging. In order to achieve this goal, packaging printing must adopt multi-color printing, that is, multi-color overprint

in the overprint process, the latter color is often superimposed with the former color, or the positioning position is misaligned, so that the printing pattern can not reflect the design effect of the product packaging, and even the large diameter, which damages the image of the product

in view of this special problem, after a period of in-depth on-site investigation and research, I made a detailed calculation from the reaction speed of electric control to the tolerance accuracy of mechanical fitting, made many improvements to the existing equipment, and formulated relevant equipment maintenance measures at the same time

1) improve the accuracy of the phase positioning of the printing plate cylinder

the phase positioning of the printing plate cylinder is controlled by the cooperation of encoder and counter. If the accuracy of counter is too low, the encoder position will be inaccurate and the position will be moved during printing. Generally, the reaction speed of counter is 3k, but 1mm error often occurs in positioning. After negotiation with Taiwan electric control company, 5K counter is produced to reduce the positioning error to 0.4mm

2) regularly lubricate and detect the transmission machinery

during the paper feeding process, if the transmission machinery cannot maintain a good and stable operation, the position of the cardboard will change every time it reaches, resulting in overprint displacement. Therefore, it is very important to maintain and test the equipment correctly. We have formulated a daily pre startup commissioning checklist, including lubrication and maintenance. At the same time, the wear limit of the paper feeding wheel and the paper feeding ring must be set. If the paper is unqualified, it must be grinded, repacked or replaced, so as to overcome the displacement and oblique position of the paperboard in the walking process

3) air suction paper feeding

the traditional printing machine adopts upper printing, and can only use the paper inspection wheel to transfer the paperboard, while the new printing machine adopts the advanced technology of lower printing and upper air suction to transfer the paperboard. The air suction paper feeding uses the wind force to adsorb the paperboard on the conveyor wheel. Its suction is uniform, without displacement and inclination, and the bent paperboard is sucked flat. When printing, it is aligned and inked more evenly

3 treatment of poor printing inking

in addition to paper problems and offset problems, there are also technical treatment problems of inking rollers on the equipment

the inking rollers are all corrugated rollers. In the printing of high standard cartons, the corrugated rollers with more than 250 lines are used, and their holes are easy to be blocked by ink residue, resulting in uneven inking, insufficient ink volume, shallow ink, etc. The traditional method is to clean with water, scrub with sodium free water or scrub with detergent, but the effect is not ideal. The service life of a new inking roller is less than a month, and the effect is obviously not as good as before

through long-term exploratory experiments, we feel that the following methods can effectively solve the problem of poor printing ink

1) add filtration in the ink bucket to prevent ink particles from entering the inking roller

2) regularly (usually half a month) use the deep cleaning agent of the corrugated roller for cleaning

3) clean the inking roller with clean water circularly at the end of work every day, and check the inking roller hole with a 60 ~ 100 times magnifying glass. There shall be no ink residue. If there is ink residue locally, wipe it with deep cleaning agent immediately

through the above points of maintenance, the inking effect of the inking roller is always good

the above-mentioned printing technology problems are of great importance to the quality of carton products in actual production. Through the understanding and improvement of equipment and good maintenance, we can produce products satisfactory to customers and improve the comprehensive benefits of the enterprise

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