The water-based ink uses water as the dissolving carrier, which has obvious environmental protection and safety features, and hardly discharges into the environment.VOCs, which is unmatched by solvent-based inks. This unique feature is being favored by more and more printing companies. However, due to the poor dispersion stability of pigments in water-based inks, it is necessary to add additives to improve them, but this will lead to poor printing adaptability and stability of water-based inks, resulting in a series of problems during use.Let us share with you the problems and methods of water-based ink in gravure production!question1: Blocked versionIn the process of using water-based ink, plate blocking is the most likely problem, mainly because the resolubility of gravure water-based ink is poor, so once it is improperly operated, it is very easy to cause plate blocking. The blocked version will cause a series of quality problems of the printed product, such as pinholes on the surface of the printed product, small characters, missing pens and broken paintings, uneven ink color, and bottom leakage. The causes and solutions of the blocked version are as follows.(1)Intermittent downtime stops printing, and the ink is dried and solidified in the cell due to the volatilization of the thinner. At this time, special tools and cleaning agents should be used to clean the printing plate, and if necessary, the printing plate should be removed, and organic solvents should be used.(Ethyl acetate)to clean. Therefore, in the case of intermittent shutdown, it is recommended to use the method of non-stop printing to prevent the ink from drying and solidifying in the cells.(2)The ink dries too quickly and is instantly fixed in the cells. In this regard, first of all, a small amount of slow-drying agent can be added to the ink. The slow-drying agent can inhibit and slow down the drying time of the ink and prevent the surface of the ink from crusting. The general dosage is controlled at3%~5%;Secondly, consider whether the ratio of the diluent is appropriate. If necessary, the ratio of the diluent needs to be adjusted. Usually, the ratio of alcohol and water in the water-based ink diluent is1:1arrive4:1However, when increasing the proportion of water, the amount of water needs to be considered. If the amount of water added is too much, too many bubbles will be generated on the one hand, and on the other hand, the ink will not dry completely, making the printed product sticky or dirty. Ink pull back phenomenon.(3)Ink viscosity is too high. At this time, the ink viscosity should be appropriately reduced, but the printing speed and leveling must be taken into account. Because the viscosity of the ink is too low, too many bubbles will be generated, which will lead to problems such as white spots on the surface of the printed product, light color of printed graphics or thick lines and small characters.(4)The mesh of the printing plate is too shallow. At this time, the depth of the cells of the printing plate should be appropriately deepened, but the quality problems that will occur when the cells of the printing plate are too deep must be considered, such as thicker handwriting, blurred small words, and unclear patterns.question2: Poor dryingDrying performance is one of the most important indicators of water-based inks. The drying speed of water-based ink is slower than that of solvent-based ink, and once the drying is insufficient, the sticking phenomenon will occur.Therefore, the drying temperature must be increased when using water-based inks, usually higher than the drying temperature of solvent-based inks10~20℃, and at the same time, it is necessary to increase the exhaust air volume.
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