In
fact, for now the multi-color offset printing for book printing or other
products, even if it is to adopt good printing conditions and reasonable
technology, it is difficult to make the ink dry in time during the printing
process or before the paper is received. Therefore, we often use the following
three ways to speed up the drying of ink film or prevent the back of printed
matter from rubbing dirty.
Dusting:
dusting is a common method in book printing. It is an effective method
for the back rubbing caused by the slow drying of ink film. When the ink layer
is thick, the amount of dusting can be appropriately increased, especially when
there is a small area of dark screen or field ink block on the surface of the
substrate, more attention should be paid to properly increasing the amount of
powder spray. Generally, the amount of powder spraying should be in the
effective range, the smaller the better, otherwise it will affect the ink color
of the printed matter, especially for the products required by bronzing and
laminating, the amount of powder spraying should be controlled more.
Air
stand: in the paper receiving part of the book printing machine, the
method of layered paper receiving is adopted, that is, the paper layer
thickness can be adjusted according to the density of the substrate and the
thickness of the ink layer on the surface. When the density of the substrate is
large and the thickness of the ink layer is large, the height of the separated
layer should be appropriately reduced) to prevent the drying ink film from
being damaged or felt dirty under the weight of the paper.
Shaking
drying: the printing materials with poor surface absorption and thick ink film
generally dry slowly. Due to the less oxygen contact between the paper stack
and the air, the oxidation drying process is hindered. Therefore, the paper
should be gently shaken every interval to make it breathable, and increase the
contact between ink and air, which can effectively speed up the drying of ink.
Finally,
let's review the key points mentioned in this paper to control the slow drying
of ink film on the surface of printed matter, as well as some technological
means for printing materials with slow drying ink
1.
Select the appropriate ink; 2. Use less additives and auxiliary agents in the book
printing process; 3. Use a proper amount of dry oil; 4. Control the amount
of water and the pH value of the fountain solution in printing; 5. It is
important to ensure the constant temperature and humidity of the environment;
6. Control the ink film thickness of pictures and texts; 7. Spray powder, air
rack and shake air.
So
far, we have analyzed some reasons for the slow drying of ink film on printed
matter and some solutions when the ink drying is slow, hoping to help you.
