What is the effect of fast and slow drying on printing quality?
Take out the newly printed product and touch the surface of the ink layer. If there is a sand like substance evenly distributed on the edge of the printed pattern, it can be determined that the ink drying speed is too fast.
Due to the fast drying speed of water-based ink, halftone printing image will be pasted quickly, and there will be burr on the edge of printing pattern. At this time, the water-based ink circulates into the ink tank, and then outputs through the scraping system, which is easy to produce drawing phenomenon.
Soft version of water-based ink drying speed is too slow, overprint effect is not solid, easy to rub dirty. Of course, there are other reasons for being dirty. This distinction needs to be clearly distinguished.
During the printing process, the color of the ink shall remain unchanged. First, make sure that there is enough circulating ink in the ink tank, and regularly check the viscosity and pH value of the ink. The printing speed cannot be too fast or too slow. When adding new ink, not only the color of the new ink should be within the allowable color difference range, but also at the end of each roll of printing.
In order to ensure the best overprint effect in the printing process, it is necessary to set a reasonable printing color level and follow the principle of reducing ink viscosity; at the same time, the printing pressure should be kept moderate, not too large or too small.
How to solve the problem of ink flow adjustment in the printing process?
If the ink leveling is not good, in addition to adjust the ink viscosity and add leveling agent, you can also try the following treatment.
(1) Check whether the paper surface coating is conducive to ink diffusion;
(3) Check whether the recycled ink is used, and try to use new ink;
(4) Ink suppliers must provide better leveling ink.