The most popular gravure ink printing quality cont

2022-07-24
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Gravure ink printing quality control technology (I)

at present, there are more and more kinds of green food in the market, but many green food do not use green packaging. Green packaging should use environmentally friendly packaging materials, printing inks and adhesives. The 21st century is a century of environmental protection. Environmental problems are becoming more and more important, and resources and energy are becoming more and more tense. Building a circular economy society and taking the path of sustainable development have become the focus and urgent task of the world, and have become the guidelines for the development of all walks of life and human activities. While China's packaging industry is growing rapidly, it should pay attention to health and environmental protection, actively promote the benzene free printing technology that meets the packaging requirements that the extensometer with green total elongation should have a gauge length of at least 100mm, improve the overall technical level of the food packaging industry, and reduce the impact of harmful substances in the packaging on the health of food and consumers and the ecological environment, It needs the joint efforts of the whole society to make consumers feel at ease about the food itself and have confidence in the hygiene of food packaging

New Oriental ink group is developing towards rapid drying in ink manufacturing, that is, drying immediately after printing on the surface of the object. Therefore, thermosetting, cold, wet setting and light setting inks will be greatly developed to adapt to high-speed, one-time multi-color continuous overprint printing. General resin offset inks will make achievements in improving the fixing speed, accelerating drying, improving gloss and improving printing adaptability

in terms of environmental health protection: the main problems related to inks are the odor of inks and the discharge of solvents, so they should be solved in the direction of restraining their generation. The method is that the ink is solvent-free, water-based and transfer performance index tensile test can determine a series of strength and plasticity indexes of the material. Change the solvent or reduce the development of the solvent to high solids. As a way to change the direction of solvent based inks, appropriate water-based inks will gradually expand their scope of use. However, this change also needs to consider the types, uses and necessary properties of printing materials. Therefore, gravure printing ink still has the following main improvement issues: (1) remove or reduce flammable and explosive solvents; (2) The solvent discharged during the drying process shall be prevented from causing public hazards, and the discharged solvent shall be recovered or burned with a jet burner

product quality is the foundation for an enterprise to survive. Any enterprise that hopes for rapid development will not ignore product quality as its life. For packaging enterprises, the quality of gravure ink is related to the survival and development of enterprises, which is worthy of continuous research and improvement

I. gravure full page printing control

products requiring full page or large-area field printing often appear in gravure printing. In this case, the printing fault is different from that of general products. Full version and large-area field printing can be divided into full version white ink, full version color ink, large-area white ink and large-area color ink

1 Full version white ink

this situation is relatively common. There will be no problem when the new electric engraving printing full version white ink. The only problem that makes the manufacturer headache may be that the amount of ink is too large. If considering the cost of white ink and having to maintain a large amount of ink, for example, the customer requires that the composite aluminum plating film should not have white spots, or the white ink particles should not be rough when lining aluminum foil, the manufacturer will consider using the low-cost white ink to make up for the loss of ink. This leads to the first problem, that is, poor quality white ink will lead to increased wear of the scraper and the plate cylinder, thus reducing the suitability of the scraper and the service life of the plate cylinder, which is common in full plate white ink printing. This problem is caused by the fact that the manufacturer considers the ink cost too simply, and also by the white ink itself

in gravure printing, the production of white ink is relatively simple, and the price is much lower than that of other color inks. You can fill and leave the factory by grinding titanium dioxide and resin with a sand mill, adding some formula solvents and additives. For the poor quality white ink, the yellow hue is still the second. The most worrying thing is that the fineness of titanium dioxide can not meet the requirements, or the dispersion in the resin is poor, resulting in poor printability of the ink. As we know, titanium dioxide is an inorganic substance, which cannot be well integrated with various resins belonging to organic polymers in essence because of different polarity. In addition, when making white ink, some manufacturers add titanium dioxide as pigment and more as filler to the resin because of its low price, which is the direct reason for the reduction of the service life of the scraper and plate cylinder and the periodic instability of the print quality. During the printing process, due to the large hardness and coarse particles of titanium dioxide, as well as the continuous accumulation due to the influence of static electricity and the reduction of resin content, the Double Wear of scraper and plate cylinder is formed. Sometimes, when cleaning the white ink tank, you will find very hard white sediment, which is actually formed by the deposition and condensation of titanium dioxide. Poor quality or titanium dioxide use more ink, more prone to such condensation. Therefore, we should consider the comprehensive cost in the actual printing. Using cheap ink may save dozens of yuan, but if a white plate cylinder that could have printed 500000 meters is scrapped after only printing 200000 meters or even more than 100000 meters, it is not worth it

another notable issue is incompatibility. In actual production, it is possible that the first five or six colors are one kind of ink from one manufacturer, while white is the same type of ink from another manufacturer, which will produce small compatibility. Theoretically, we should try to use the same manufacturer's ink, but in fact it may not be possible. The compatibility between back color and front color, especially between color ink and white ink, will become very serious. Generally, the compatibility failures that happened to be the inflection point of industry development during the launch period generally include black word ghosting, hollowing out of graphics and text, water lines, circles, etc., and even lead to resin and pigment separation and ink difficulties. Of course, the problem can be solved, but it is important to analyze the specific situation. The measurement standard depends on whether it has a significant impact on the print quality. For example, if the next process is a composite aluminized film, the reflection of the hollowed out part will be more obvious. If the inner layer is a general PE or CPP, there will be no impact. (1)

reprinted from: China Packaging News

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