[Chinese Packaging Network News] In the sample printing, there is a lot of careless printing problems, so it is said that printing is a meticulous task that requires us to take every step of the process carefully. If we do not promptly solve the problems that appear on the printed products, it will inevitably be considered as a defective product, which will not only impair the quality and quality of the printed matter, but also reduce the customer's trust and evaluation of the company. We must be extremely careful about all kinds of issues. So why are bubbles and how to avoid them?
In the printing of samples, the reason why the substrate appears air bubbles on the ink is mainly reflected in the following aspects:
1. The poor pre-treatment of the substrate, that is, the substrate has not been clean before, so that the surface is rich with dust or oil stains.
2. Bubbles in the ink. Mostly caused by the improper deployment of ink, when we add additives or solvents for mixing, the ink will be mixed with a little air bubbles, let alone, then, the lower viscosity ink will naturally deaeration, and the viscosity of the ink It cannot be defoamed naturally. Although some of the bubbles will naturally disappear during the printing process due to the ink swivel chair, some will grow bigger and bigger. Therefore, in order to completely remove the air bubbles in these inks, we need to add about 0.1% to 1% of defoamers to the ink, but be careful not to overdo it and produce new air bubbles.
In addition, it should be noted that when the ink is swollen and foamed in time, the ink on the surface of the main substrate will have good fluidity and wetness, and the air bubbles on the surface of the ink film will gradually disappear, eventually forming a flat printing ink film. However, if the ink bubbles are not eliminated, the film surface of the final ink will be uneven. Ordinary ink will be degassed by the screen when it passes through the screen. In order to allow the ink to have a better defoaming effect, it is better to use some hot water or boiling water when stirring.
For some transparent red, transparent blue, transparent green ink. Because of the reduced amount of organic pigments in the microparticles, the linking materials of these inks are characterized by easy foaming, but if we add some release agents, tackifiers or thinners into them, they can also be made stable. High-quality, well-adapted ink.
3, printing speed is too fast or uneven, but also lead to a big cause of air bubbles, the improvement method is very simple, only need to reduce the printing speed, and ensure the printing speed is as uniform as possible.
If none of the above can help eliminate the printed inks, consider using other types of inks.