Innovative Application of Paper Packaging Printing Technology (III)

3.2 Flexo Technology

New flexible plate and thin plate process, sleeve type plate and computer direct plate making technology, environment-friendly UV ink, high network cable ceramic anilox roller laser engraving technology, closed squeegee blade system, gearless transmission technology, no downtime change The development and application of related technologies such as roll devices and automatic control technologies have promoted the rapid development of flexographic printing.

(1) Thin plate and CDI technology

The improvement of the quality of the photosensitive resin plate and the appearance of the thin plate process have laid a good foundation for improving the quality of the plate. The emergence of the CTP technology and the emergence of the digital flexographic plate making technology (CDI) can effectively overcome the dot gain phenomenon and guarantee Print quality, shorten production cycle, reduce cost.

The digital thin sleeve plate has good stability, can effectively control the control of dot enlargement, reduce photopolymer, improve image quality and register accuracy. Not only can improve the quality of printed paper packaging, flexographic quality to offset and gravure quality level. It can also reduce the printing pressure, reduce the number of plate cleaning, prolong the service life of the printing plate (time limit can be increased by 10-25%), further reduce the machine preparation time, reduce the number of shutdowns and IT (10-20%) when the machine stops.

The CDI system jointly developed by DuPont and DuPont Xili can transfer the digital information directly to the laser photosensitive plate. Spark XT, a CDI plate-making machine developed by Esko-Graphics, is mainly aimed at the packaging and printing market, especially for small and medium-sized label and folding carton flexo printing companies. As technology continues to advance and the cost of various systems for flexographic digital imaging and plate-making systems has continued to decline, the proportion of paper products such as cartons, paper bags, and multi-layer bags has increased.

(2) Sleeve type high mesh ceramic anilox roller

The laser-engraved ceramic anilox roller is used as a primer layer on the surface of the treated base roll, and then plasma sprayed with high-temperature ceramic powder. After grinding and polishing with a diamond, a high-energy laser beam is used to accurately sculpt the contours. Steep nets, the final fine throw. The number of screen lines and the amount of ink in the cells are the most important parameters for making laser-engraved ceramic reticles. The anilox roller with a high number of lines can form a thinner and more uniform ink layer, which can meet the requirements of printing layers with a rich print layer, in particular to meet the needs of its high-light portion, and can reduce the enlargement of dots during printing, and maintain a constant and uniform Pass the amount of ink.

Sleeve type high-line ceramic pottery anilox roller. Ultra-high-energy laser beam engraving technology and sleeve type anilox roller structure composed of mandrel, gas-supporting roller and sleeve are used to ensure the quality of high-precision anilox roller and enable quick replacement of anilox roller. Plate roller, anilox roller sleeve structure and direct drive technology (that is, the rotation of the anilox roller is directly driven by the printing plate roll), solves the problem that the repeat length of the flexographic printing product is limited by the gear pitch . Therefore, when replacing printed products of different perimeters, the mandrels and gears of the plate cylinders, anilox rollers, and gears need not be replaced, which greatly shortens the time taken to change the platen roll and the anilox roller when changing products.

Carbon dioxide laser engraving ceramic anilox roller line up to l000LPI, using a special ceramic layer or super hard ceramic layer, can increase the service life of ceramic anilox roller and reduce the cost of use.

The ceramic anilox roller processed by YAG laser engraving technology has smooth mesh walls, neat network walls, high gloss, accurate ink transmission, and low blade loss. Not only does the ceramic anilox roller have a long service life, but it also extends the length of the printing plate. Service life. High-power, high-precision YAG laser engraving machine can engrave 16001pi anilox roller.

(3) Closed double blade cavity ink system

Two-roller type, forward scraper type, reverse scraper type structure can achieve quantitative ink supply, but the ink is often directly exposed to the atmosphere over a large area, so that the solvents of the solvent ink volatilize into the surrounding air, resulting in ink characteristics. Changes and environmental pollution problems: If you use water-based ink, it will produce air bubbles, which will affect the printing quality.

Closed double blade cavity ink system is composed of ceramic anilox roller, two scrapers, sealing strips, ink storage containers, ink pumps, inking hoses and other components. In a fully closed system, scrapers, seals, gaskets, and pressure plates are all mounted on a cavity-type bracket, and they are mechanically (or pneumatically or hydraulically) pushed against the ceramic anilox roller and apply a certain pressure. The ink delivery tube and the return tube are respectively connected to the ink pump and the ink storage container to achieve quantitative ink supply. The reverse scraper structure is suitable for high speed operation, reducing solvent evaporation and environmental pollution in solvent inks. The system can also be quickly docked with the automatic cleaning system to facilitate rapid cleaning to reduce ink change time and downtime.

(4) Eco-friendly flexo ink

Today, people pay more and more attention to environmental protection, water-based inks and UV inks to meet market demand, and promote the application of flexographic printing in the field of packaging and printing. Not only can be used for a variety of coated paper, offset paper, whiteboard printing, but also in gold and silver cardboard, synthetic paper, adhesive paper and corrugated boxes and other printing carrier printing.

Water-based (or water-based) ink uses water as the main solvent, which is non-toxic, non-polluting, and has no residual odor. It completely eliminates the harm to the human body from certain toxic substances in solvent inks and the pollution to packaged goods, effectively reducing air pollution. , to improve the environmental quality and printing operating environment, especially for drugs, food, beverages, tea, tobacco and tobacco, as well as daily necessities contact with the human body, and other strict requirements on the health of the packaging printing.

Under ultraviolet irradiation, the photoinitiator in the UV ink is excited to be decomposed into free radicals, and the free radical causes the crosslinking reaction to occur rapidly, so that the colloidal component instantly becomes a solid. Since UV inks are mainly composed of pigments, photosensitive resins, reactive diluents, photoinitiators, and additives, and do not contain volatile organic solvents, they can greatly reduce VOC emissions, and they consume less energy, have a small footprint, and are easy to dry. high productivity. Since UV inks do not have the problem of volatilization of water or solvents, the transfer and reproducibility of the dots are good, and the colors are more vivid, which greatly promotes the improvement of the quality of the flexo printing. Although the drying cost of the UV ink is significantly higher than that of the water-based ink, the UV ink has a good light-curing efficiency and ink layer properties, and can well protect the surface of the printed product.

(to be continued)

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