The effect of the Scraper Blade is to scrape off the extra ink in the non-graphic part and keep the minimum amount of ink in the non-graphic part. This very thin ink acts as a lubricant between the scraper and the plate. If the ink layer is too thick, the non-graphic part of the printing will leave a vague mark; if the ink layer is too thin, the wear between the squeegee and the plate will be too large. The factors that affect the printing plate resistance to Indian force are as follows:
① the hardness of the scraper. General scraper hardness of the printing plate hardness of half, that is about 550HV. Scraper hardness is too high, to speed up the layout of the wear; scraper hardness is too low, it will make the squeegee wear too much, frequent replacement.
Scraper in the assembly must ensure that the edge of the line with the roller parallel to the bus, to prevent the generation of wave edge, in order to avoid unnecessary operation to increase the Scraper Blade.
② Scraper angle. Scraper blade angle is too large, easy to clean the layout of the ink and make the picture clear, it seems likely that the ink layer is too thin, but also easy to scratch the layout. Scraper angle is too small, the impurities in the ink can easily be brought into the knife stitch, will damage the layout, but also cause the Scraper Blade and other printing processing failure.
③ Scraper pressure. The principle of Scraper Blade pressure control is to minimize the contact pressure of the scraper without compromising the quality of the print. The greater the pressure, the greater the friction between the drum and the scraper, and may also completely change the angle of the scraper, and it is not possible to clean the layout of the ink, and to further increase the squeegee pressure. Will cause excessive wear and tear of the layout.
④ wear of the doctor Scraper Blade. The wear of the doctor Scraper Blade occurs mainly in the area where the graphic area is in contact, so that it is necessary to use the same doctor Scraper Blade instead of re-grinding, so that the wear of the Scraper Blade is inconsistent, Of the pressure, serious will not be able to screen the excess ink scraping the net, forming a knife line.
Viscosity In general, the printing process with the solvent volatile, the viscosity of the ink becomes larger, the ink on the layout of the larger viscosity, so to scrap the layout, you need to increase the viscosity of the ink less than the additional Scraper Blade. The viscosity of the ink should be controlled within the appropriate range and kept consistent during the process.
② impurities in the ink and particles. Impurity and particles in the ink may always be involved in the gap between the plate and the blade edge of the Scraper Blade, which may scratch the layout and Scraper Blade.
③ ink fineness. In production, the white version of the other color version, the network is easier to light, especially when the white version as a common version of the time, this is white ink in the titanium dioxide particles thicker reason.
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