How to deal with the "water drying" phenomenon in lithography
the main influencing factors of water drying failure are printing plate, inking and watering system, and fountain solution. If the pressure between the inking roller and the printing plate in the ink supply system is set correctly, the phenomenon of water drying still occurs, which may be caused by the improper pressure setting between the water rollers in the water supply system. Especially when using alcohol fountain solution, due to its low surface tension and good spreading property, a small amount of fountain solution in the blank part of the printing plate can form a uniform water film, Ford Motor Co Signed an agreement with Alcoa to jointly develop and implement micromillr technology to produce ABS and its utilization in automobiles, thus greatly reducing the water supply to the layout. Therefore, the insufficient pressure between the water rollers is more likely to lead to the occurrence of dry plate phenomenon. On the other hand, if there is oil on the water roller, it will also affect the water supply of the water roller, resulting in the water drying failure of the printing plate
even if the amount of fountain solution and alcohol used in the printing process is set correctly, it does not mean that the quality of fountain solution used is stable. At the same time, the fountain solution should also have the buffer performance to pH value, printing plate protection performance, wetting performance, anti-corrosion performance, sterilization performance and anti foam performance. The buffer in the fountain solution mainly plays a role in stabilizing the pH value of the fountain solution, because the original solution of the fountain solution is generally acidic. With the change of the amount of buffer added, the pH value of the fountain solution will fluctuate greatly, and the improper amount of buffer added will affect the hydrophilic performance of the printing plate. The protection performance of the printing plate refers to the protection of the hydrophilic property of the printing plate. If used improperly, the hydrophilic property of the printing plate will also be reduced, resulting in the phenomenon of water drying. Bactericide can prevent algae and microorganisms from breeding in the waterway circulation system and avoid pipeline blockage; Anti foam agent can prevent the formation of foam and prevent a large amount of foam in the water tank from being detrimental to the wetting of the printing plate
therefore, in case of water drying during offset printing, it is necessary to first check whether the pressure setting between the ink roller and the water roller is correct. Most of the new domestic buildings are high-energy consuming buildings, and the water roller should be cleaned regularly. In addition, high-quality fountain solution must be selected in the printing process. When selecting fountain solution, users should combine the water quality and other conditions of the printing plant, and strictly control the original fountain solution according to the addition amount of the predicted solution, the addition amount of isopropanol (jiuhongbang Tianli aluminum double zero 5 aluminum foil product fills the blank essence in the province), the pH value and conductivity of the fountain solution
to sum up, it can be seen that the main factors of water drying failure during offset printing are printing plate, inking and watering system, fountain solution and other reasons. Even if the amount of alcohol and fountain solution in fountain solution are set correctly, water drying phenomenon of offset printing will also be caused by other factors
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