1. Printing white spots caused by powder dripping of printing materials
Depower of printed materials is also prone to printing white spots. Different from paper wool and paper scraps, the powdery state of the printing material is due to its lack of surface strength, which causes the tiny powder particles to adhere to the surface of the printing material during the printing process, thereby forming white spots. This type of problem is characterized by a small number of white spots, and their location is not fixed. Looking through a magnifying glass, there is almost no ink in the white spots. This is because the fine powder on the surface of the material is stuck by the ink, forming tiny depressions, and the ink cannot cover it.
Encountered such problems, can be resolved by reducing the viscosity of the ink. If the effect is not obvious, the company can also print a layer of primer ink or thinner on the surface of the substrate to solve the problem of chalking. Since the primer ink and removable agent can cover the surface of the substrate, it is equivalent to scraping a layer of putty on the surface of the substrate. The printed ink is actually printed on the base coat ink or removable agent, which will effectively reduce the white spots caused by the substrate powder.
2. Static electricity caused by printing white dots
Some film adhesive materials will generate static electricity during the printing process, which will push the ink and cause white spots. When the white spots are observed under a magnifying glass, an explosion effect will be produced around them. At the same time, the obvious phenomenon is that the surface of the printed material will have strong static electricity during the printing process, and the front-line printing operators tend to be electrified.
3. White spots caused by uneven printing materials
Sometimes the non-smooth surface of the substrate can also cause white spots in the printing. The main form of printing white dots caused by this reason is that the white dots are getting denser and denser. Observing under a magnifying glass, it can be found that the printed surface is covered with such dense white dots.
When encountering such problems, printing ink can be used to increase the flatness of the substrate surface to solve the problem of white spots. Of course, for some larger field pattern labels, the process of printing the field twice can also be used to solve the problem of white spots.
4. White spots caused by paper wool or dust during printing
Printing white spots caused by paper wool or dust is very common. Printing white spots caused by dust in the printing environment are usually obvious and fixed locations. But the white spots caused by paper wool are not so regular. Under normal circumstances, there are not many white spots at the beginning. After printing for a period of time, there will be more and more, and there will be obvious white paper lint and paper scraps on the press roller of the machine feeding part.
Encounter this kind of problem, you need to analyze the specific reasons. If there is more dust in the printing environment, the workshop needs to be cleaned. An effective method is to sprinkle the floor and mop the floor, which can be significantly improved under normal circumstances. If printing white spots are caused by paper lint and paper scraps on the surface of the paper, a dust-removing cloth can be installed at the feeding part of the machine to reduce the occurrence of white spots. The quality of the product is very strict, and it can also be printed before the substrate is printed, so that it can be used to emboss the paper.