European Polishing Skills

Recently, more than 540 printing professionals from 23 countries gathered to innovate in glazing and related technologies and processes, and to discuss new consumables. The event was hosted by Mr. Jurgen Veil, Director of Kappa Radebeul Sheetfed Marketing. According to him, before the seminar, a survey was conducted on the European printing factory. Based on the survey's tailor-made seminar, it was possible to The key issues are elaborated.

The first item on the hardware conference agenda is the coating system and its underlying principles. The difference between Tresu and Harris & Bruno's web ink inking system was clarified by Mr. Henrik Christiansen and Gerhard Palinkas respectively. They also put forward suggestions for installation and maintenance. The focus of the discussion was on the useful life of the squeegee and other components, the way in which the preparation time was reduced, and how much the coating thickness and the type of anilox roller used determine the amount of coating. Mr. Palinkas enumerated the automated options used during job replacement and the potential savings.

Zecher's Oliver Leithauser and Praxair's UweNeis proposed the surface structure of the anilox roller, the shape and characteristics of the cell, and the related specifications of the coating oil.

Followed by dry experts from Mr. Jan Lkels from Adphos Eltosch, Mr. Andreas Doderlein from Grafix and Mr. Tilo Steinborn from KBA. Mr. Lkels elaborated on the TwinRayUV system for curing four-color inks and coating oils on thermosensitive substrates: After a shutdown, a rotary shutter enables the lamp to turn on again immediately. Mr. Doderlein briefly summarized the combination of a hot air knife, an infrared dryer, and both. The ATC system for these dryers promotes reproducibility and reduces operator workload by analyzing print output, ribbon warming, and ambient temperature. Mr. Doderlein also discussed inertial, excitonic atom, CM and cold air UV drying system both positively and negatively.

Mr. Steinborn described KBA's Varidry technology. In fact, the dryer module can be inserted anywhere along the printing line so that, regardless of the challenge, each coating job can quickly be optimally configured. In the infrared irradiation process, the dual-tube carbon filament lamp can reduce the energy consumption and reduce the influence of heat on the base material during the infrared radiation process.

Substrate material

Mr. Christoph Weinert, Director of Quality and Technology at Schneidersohne GmbH, Germany, introduced the substrate materials used in traditional varnish and hybrid varnish. Using surface textures and cross-sections of various materials, Christoph Weinert demonstrated that high gloss coated substrates are generally more suitable for UV glazing and hybrid glazing. Sappi's Mr. Hermann Nax and UPM's Peter Hannemann also joined in to discuss the issues related to online light. These include differences in the absorption of oil and water by paper. If the paper is too absorbent, it can easily cause the coating to "sink." For high-profile jobs, such as high-gloss and matt finishes, the glazing applicability of the base material should be tested prior to production. Other common problems include loss of whiteness (yellowing), cracking, and odor from UV drying. It has been proven that matt coated substrates with high basic whiteness are least likely to yellow. Optical brighteners can be excited by ultraviolet light, but they can also be destroyed, so its stability is a key factor. Cracks can usually be avoided by creasing the material in advance, but UV coatings must be flexible and flexible. Odor is the decomposition product of chemicals in the adhesive. Paper and adhesive producers must work closely together to design the right mix. However, in addition to these potential key features, UV coatings also have some unique advantages, including instant cure, anti-friction, and optimal gloss.

Dr. Jutta Richter from Weilburger Graphics explained the properties of the base material and its effect on water-based, UV and special types of coatings. He explained differences in formulas and properties such as the following special coating aspects: High-gloss coating for single-sided or double-sided printing (more sturdy adhesive with little or no sticking) and labeling Varnish (Special formula for lightweight paper that does not easily curl). Dr. Richter also gave helpful hints to solve the problem: elimination of odor and stickiness, problems associated with diffusion and wetting, and reductions in gloss and resistance to friction. Vegra's Joachim Frings emphasized the specification of coating oil for high-speed wired lighting. He compared the gloss and drying time of different varnishes on the same substrate material (GD2), and concluded that: with proper varnishes and embossing techniques, the on-line light energy reaches 18,000 sheets/hour. The high speed. TerraLacke's Mr. Frankkamphuis studied representative problems associated with waterborne varnish, and provided solutions to some of these problems (stacking, reticulation and blistering). How to solve the problem is also the theme stated by Mr. Fritz Laufs of SunChemical Company. He recommended the method to clear orange peel effect, adhesion and other typical problems.

Mr. Andre Salie, from the pigment manufacturer Merck, discussed the positive and negative aspects of the use of special varnish, such as iriodin pearlescent pigments, and concluded that the benefits outweigh the disadvantages. At the end of the speech, he put forward some suggestions for correctly handling this coating oil (iriodin is inorganic, insoluble in water, non-toxic, and can be treated together with other coating oil wastes).

The complexities of chemical properties of blankets, lacquered and chemical glazing, blankets, rollers and prints have also been explained in detail. Thomas Leuschner of Flint Group summarized the film substrate and aluminum flexo printing plate, as well as the first digitally imageable aluminum-based glazing plate (nyloflexGoldA116DII). The advantage of this plate is that it can realize error-free imaging. Higher resolution and wider imaging latitude to precise image positioning during darkening, deeper dark tone, and corresponding enhancement of the wiring operation.

Michael Jotzo of Folex talks about peelable and compressible photosensitive resin glazing, as well as self-adhesive blankets for plates. He also highlighted possible sources of problems: from the tearing of the glazing backing to the rollerjump, and defects in the glazing coating and the accumulation of coating oil.

Simon F. Bornfleth from Dayinternational answered the following questions: Which combination of glazing blankets and liners will achieve the smoothest, most uniform coating finish; How to prevent lining swelling; When can blankets Traditional inks, mixed inks, and UV inks are used together; how blankets affect streaks and dot gains.

For the topic of double-sided printing with high-gloss water-based coating, Matthias Kuhn of FujiHunt company highlighted the interaction of parameters such as fountain solution, dusting, drying equipment, fast-drying anti-sticking coating, and these parameters. The effect on image copying and quality consistency. Reinhard Sommer of Felix Bttcher Co. used the swollen test to show how the ink roll material reacts during the conversion from the mixed ink to the traditional ink. Regular maintenance of the ink roller, the use of Fogra certified detergents and inks, correct use of detergents, and deep cleaning can effectively prevent changes in the amount of ink and surface properties.

Connected to the online demo at KBA's newly established printing and testing facility in Radebeul, featuring a Rapida 105 six-color press with a static eliminator and two sets of glazing units, demonstrating some intoxicating glazing and die-cutting effect.

First, four colors were printed on a self-adhesive film with a backing with a mixed ink, followed by UV matting on an offset printing plate on a sixth printing unit. Using this method can make the gloss level around 5. Then start the first coating unit and apply a layer of high-gloss UV coating. Participants witnessed the contrasting effect of the matt/high light obtained on the offset printing positioning mechanism and were impressed (about 5 gloss levels in the matt area and more than 85 in the highlight area).

After the printer paused, the second coating unit was actuated, and the printed and coated film was subjected to line cutting to make a single shape with a jagged edge and a stamp size. The challenge is that the backing must not be damaged by die cutting, as this requires a finer micrometer, similar to the pressure-sensitive printing on corrugated paper. This is only possible if the impression pressure setting on the impression cylinder is absolutely accurate and the roller is 100% uniform.

Reprinted from: Global Box Industry