Several problems that should be paid attention to

2022-09-21
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Several problems that should be paid attention to in UV glazing

more than 20 years ago, Roland first launched an online glazing printing machine to the business community, which was warmly welcomed by packaging and general commercial printers. From then on, the gloss and surface protection of packaging and advanced brochures can be enhanced by glazing without additional processes. In recent years, Manroland has continuously expanded the application scope of coating enhancement effect: gold, silver, pearlescent effect, special gloss or frosting effect, protection, embossing, fragrance, etc. - all these coatings can be coated online according to the specified thickness. The driving force behind these encouraging developments comes from the emergence of printing presses with two glazing units and the use of closed scraper or roll coating technology

now, these technologies are reflected in all Manroland printing presses. All Manroland printing presses can provide economical and finally convert the v/a voltage and current into a 4 ⑵ 0ma standard current output signal that is linearly corresponding to the liquid level and pressure of the measured medium (liquid), which is in line with the environmental protection system

online glazing using water-based dispersion paint has become a standard application. For example, the international influence of the plastic extruder industry on spot color continues to rise, and light can indeed enhance the appearance effect of prints

if special high gloss is required, ultraviolet (UV) coating is becoming more and more popular. This kind of glazing coating is friction resistant, which not only provides a good protective layer, but also makes it visually attractive due to its current and bright surface. Packaging printers are very interested in these advantages. Therefore, when the medium and equal format printing machine proves the effectiveness of these reforms (two glazing units plus multiple drying devices and tail drying), the large format printing machine naturally provides this special enhanced structure. Users of large format printing machines are generally very interested in ultraviolet (UV) glazing after printing with ordinary ink in the production of folding cartons

in order to obtain the best effect, printing machine, polishing machine, drying and other methods must meet certain prerequisites. The only way to get the best results is to match the composition of the printing press with the special requirements of individual users

pay attention to the line of the texturing roller

Roland worked with its customers and supply partners to develop a closed scraper method in 1993, which ensures that the thickness of the glazing coating is extremely uniform. The corrugation roller with different bearing capacity can ensure accurate glazing and can be repeated. The amount of paint carried by the corrugated roller varies with different live parts. The normal requirement is between 6 and 30 cubic centimeters per square meter

in fact, only 25 innovative materials with the above nominal bearing capacity are used for engine utilization, and% to 35% of the wet paint of the door structure is transferred to the surface of the substrate. The different line conditions on the surface of the corrugated roller enable the machine to transfer the different amount of paint required. If we pay attention to the corrugated roller for a long time and use it reasonably, we can ensure the stability of product quality

pay attention to the combination of circulating system

to meet the requirements of handling different coatings, the circulating system of coatings must be the most appropriate combination. The stable quality of the coating is related to the input, storage, pumping principle and temperature stability of the coating. These factors must be matched with the glazing unit used

pay attention to the equipment cleaning before changing the coating

due to the increasing number of different applications, Manroland has several completely separate glazing circuits on the glazing unit unit, which can quickly and economically change from one coating method to another. This not only saves preparation time, but also saves paint and cleaning agent. Dispersive coatings are not compatible with UV coatings. At the same time, changing from pigmented coatings to transparent coatings requires thorough cleaning. In order to ensure stable quality, cleaning is very important when replacing paint

on the large format flowing cloth surface. The different changes of brightness are particularly significant. Therefore, it is very important to maintain uniform brightness of the whole surface and apply the coating evenly

but the fading effect will lead to uneven brightness on the surface of the print. Due to the difference of printing time and different physical processes, the ink layer and coating layer dry at different rates. When different layers of material mix and change in volume, it emits gas and its surface deforms. Cracks formed due to deformation will lead to a reduction in gloss

pay attention to the angle for measuring gloss

a certain reflectance can be selected to measure gloss. The "mirror surface" reflects 100% of the light, and only part of the light is reflected due to the quality of the coating surface. Considering the gloss degree, the angle of measurement must be selected to provide reliable gloss change data. The angle of measurement is very important, because the pigment penetrates into the depth and there is dispersion. The human eye responds strongly to gloss on a black background

pay attention to the method of measuring scratch resistance and adhesion

the scratch resistance and adhesion characteristics of the coating are important indicators of the post press processing process, as well as the durability of the printed matter. Users sometimes use unscientific methods to judge these characteristics, such as scraping with nails or sticking with tape. These are subjective judgment methods, which mainly rely on the judgment of each customer. There is no measurable or replicable data, but it can be used as a reference. At present, there is no objective test standard. After production, the adhesion of the coating can only last for a few hours if it remains stable after many days. During this period, the ink is oxidized and dried, producing gas, which accumulates between the ink layer and the coating, thereby destroying the adhesion. Therefore, it is reasonable to check the adhesion only a few days after the completion of printing. Acetone is very suitable for testing the curing degree of UV coating; Wipe the coating with a cloth soaked in acetone. If it is not cured well, the coating will be dissolved

the German Printing Association recommends some test devices to check the ability of anti stripping and anti caking. The resistance of printed matter can be tested according to the methods provided by "German industrial standards" din16524 and din16525. (LAN)

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