During the printing process, ink may produce a large number of bubbles. These bubbles are attached to the printing plate cylinder, which will cause some of the dots on the pattern to disappear, and white spots will appear on the printed product. So why are there bubbles in the ink? How to avoid this situation? First of all, we must understand the reasons for this situation.
1. The surface tension of the printing ink is relatively strong, which is greatly affected by the resin and solvent used in the ink. Sometimes the viscosity of the ink is large, and it is easy to produce bubbles.
2. The ink tank or circulation device is defective. A large number of bubbles are caused by poor ink flow in the ink tank or circulating pump. When using the ink pump to circulate the ink, the ink flows from the ink tank to the circulation barrel. Due to the drop and the stirring action of the printing plate cylinder when the printing plate cylinder is running at high speed, air bubbles will be formed in the printing ink.
3. On the printing machine with direct ink supply, the magnetic stirring rod bends and jumps in the ink tank, causing air bubbles.
4. Add an appropriate amount of defoamer. Although there is a dedicated defoamer, too much will have a bad effect on the properties of the ink, improper use will cause bubbles, so it should not be used more.