of printing materials
Reason: the performance of this kind of
problem is that the number of white spots is not large and the position is not
fixed. Different from paper wool and paper scraps, the powder drop of printing
material is due to the lack of its own surface strength, resulting in the ink
adhering to the small powder particles on the surface of printing material,
thus forming a white spot. With a magnifying glass, there is almost no ink in
the white spot.
Solution: reduce ink viscosity. If the effect
is not obvious, qualified enterprises can also print a layer of primer ink or
desalting agent on the printing surface to solve the problem of powder drop.
Since the primer ink and desalting agent can cover the surface of the printing
material, which is equivalent to scraping a layer of putty on the surface of
the printing material, the printed ink is actually printed on the primer ink or
desalting agent coating, so as to effectively reduce the printing white spots
caused by the powder drops of the book
Cause: sometimes the surface of bearing
material is uneven, which will also lead to printing white spots. For this
reason, the main form of printing white spots is that there are many white
spots and dense white spots.
Solution: for some large on-site pattern
labels, the problem of white spots can be solved by printing twice. Generally
speaking, printing primer ink can be used to increase the smoothness of the
surface of printing materials to solve the problem of white spots.
hair or dust
Printing white spots caused by dust in the
printing environment are usually obvious and fixed in position. However, the
white spots caused by paper hair are not very regular. Generally speaking,
there are not many white spots at the beginning. After a period of printing,
there will be more and more white paper, wool and paper scraps on the drum of
Solution: if there is more dust in the
printing environment, the workshop needs to be cleaned. The effective way is to
spray water and mop the floor. If the printing white spots are caused by wool
and paper scraps on the paper, dust removal cloth can be added to the feeding
part of the machine to reduce the generation of white spots.
4. Causes of static electricity
Cause: some film adhesive materials will
generate static electricity in the book printing process, which will
push away the ink and lead to white spots. The white spots caused by this
phenomenon were observed under the magnifying glass, and the explosion effect
was found around the white spots. At the same time, it is obvious that there
will be strong static electricity on the surface of printing materials during
the printing process, and the first-line printing operators often get an
Solution: install electrostatic precipitator
on the printing press. For book
printing companies without conditions, humidifiers can be installed
next to the machine to increase the humidity of the local environment, and can
also play a good role in removing static electricity.
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