After printing, in order to increase the gloss of printed products and improve product quality, it is often necessary to add a layer of coating oil. The amount of varnish used is related to the final effect of the printed product. If the quantity is large, it will produce a pull coat that will affect the quality of the printed product. If the amount is small, the expected effect will not be achieved. The author combines many years of practical experience to talk about several things that should be noted when glazing.
1. The amount of varnish should be controlled properly. The specific method is as follows.
(1) Touch the ink roller with a finger to control the uniformity and the ink output of the ink. Generally, the ink thickness is about 0.05 mm. The amount of varnish used is usually about 2.5kg varnish to print about 4,000 sheets of folio paper.
(2) Use a white paper to make a full version. Under the fluorescent lamp, visually measure whether the coating layer is even.
(3) In the printing process, it is necessary to check whether the varnish in the blank area meets the requirements. In particular, it is necessary to avoid the phenomenon of large amount of oil at both ends of the paper and a small amount of intermediate oil.
2. Before glazing, test the full version with white paper, observe the phenomenon of concave rubber under fluorescent light, this method is very intuitive. In the process of glazing, a few white papers are often printed to check the quality of the coating.
3. When printing, add appropriate amount (generally controlled within 3%) of dry white oil to avoid drying the printer's rubber roller and tear it.
4. Printed products cannot be stacked too high. Generally, no more than 3000 sheets of 128 g/m2 coated paper are stacked.
5. Try not to spray or spray anti-stick powder when printing, so as not to affect the gloss of the printed material.
6. Wash the blanket and roller frequently to avoid drying of the coating.
