What should I do if the uv ink is poorly cured?
author: Uvink
2023-04-06
Cure speed refers to the rate at which the ink cures into a film on the print media. It is an
important indicator of ink drying performance and a key indicator of uv inkjet ink curing
process. The advantage of uv inkjet inks is their instant drying properties. The higher
curing speed is very beneficial to the drying and film formation of the oil wall. After the ink
is sprayed onto the printing medium, it can be reached instantly after being irradiated
by the uv light source. It can not only improve the efficiency of printed products, but also
prevent smudges. The gloss and vividness of printed products can also be rendered
with high quality.
First of all, it is necessary to judge whether the curing is complete before the problem can
be solved. In practice, several methods for judging the curing of uv inks have been
summarized, which can be classified into appearance observation methods, physical
testing methods and chemical testing methods. Physical testing methods: in printed matter
Spread a piece of paper on the uv ink layer, press the paper with your hands and rub it
on the uv ink layer, if the curing is not complete, the surface of the ink layer will be destroyed.
Use a pin to scratch the surface of the uv ink layer, and then observe the scratches under
a magnifying glass of 200 times. If the scratches are jagged, it indicates that the uv ink
layer has been completely cured.
Chemical test method: This method needs to use acetone solvent to drop it on the uv ink
layer. If the ink layer can be dissolved, it means that it has not been fully cured. If the curing
speed is not high enough, to ensure that the printed matter is dried immediately, it is
necessary to increase the energy of the uv light source or prolong the curing time,
which is time-consuming and laborious, and the advantages of uv inkjet inks no longer exist.
In order to cure completely, it is necessary to keep the temperature and humidity of the
workshop suitable. During the printing process, changes in the temperature and humidity of
the workshop will affect the performance of uv inks and substrates. For example, when the
workshop temperature is low and the humidity is high, the photocuring reaction of uv inks
is slow. The ability to bind to the substrate will also be reduced. Therefore, when printing
with uv ink, the temperature and humidity of the workshop must be controlled within an
appropriate range. Generally, the temperature of the workshop should be controlled
at 20-25°C, and the relative humidity should be controlled at 50%-65%.
Ensure the ultraviolet light intensity of the uv lamp tube. The ultraviolet light intensity of
the uv lamp tube directly affects the curing time of the uv ink, which is also a key factor
affecting the internal hardening of the ink film. When the intensity of ultraviolet light
becomes low, even if the accumulated light amount is increased by increasing the
irradiation time, the hardening property inside the ink film cannot be improved,
so the uv lamp tube that exceeds the actual service life cannot fully cure the uv ink.
In order to ensure the curing quality of uv ink, the uv lamp should be replaced
in time after reaching the actual service life.
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