Misunderstanding in Offset Printing Ink

In the offset printing process, the ink used is often adjusted to suit the printing needs of different products and different papers. Adaptability of the ink is achieved by adding suitable auxiliary materials to the ink. Because people's understanding of auxiliary materials is not the same or prejudiced, it is very likely that they will enter certain “misunderstandings” in actual production, resulting in unsatisfactory results.
First, completely replace the varnish with a de-sticking agent in the production process, when printing a large-scale field version, the ink is not easy to be beaten during the transfer process of the ink roller or paper "linting", printing rough phenomenon, generally It is caused by the high viscosity of the ink.
Detackifiers and varnish can reduce the viscosity of inks, but their properties are not exactly the same. Detackifiers also have the ability to inhibit ink drying while reducing the viscosity of the ink and to reduce the adhesion of the ink layer to the paper. Ink in the ink, can play a role in reducing the viscosity of the ink and increase the ink fluidity, although the impact of the ink layer drying speed is not obvious. If an excessive amount of detackifying agent is added to the ink to reduce the viscosity of the ink, it is likely that the phenomenon of “imprinting” or “powdering” of the ink layer is likely to occur. Therefore, when adding an anti-adhesive, it is necessary to pay attention to the “quantity” problem, and it must not be taken lightly to keep it within a proper proportion, and at the same time increase the amount of desiccant to avoid the above-mentioned adverse consequences.
Second, the use of white ink as a dilute individual ink needs to be added in the original ink diluting agent to make it a light-colored ink, this diluting agent should have a colorless and transparent nature. Both bright and Weili oil are ideal diluting agents. It has the effect of not changing the original ink color but changing the depth of the original ink.
It would be inappropriate to use white ink as a diluting agent. Because the white ink has a white hue, it will change the hue of the original ink so that the original ink tends to be brighter and younger than the jade ink, which is not a light-colored ink, which is contrary to the willingness of the operator to require light-colored ink. In the offset printing process, if the white ink component in the ink is too much, due to the large specific gravity of the white ink pigment, pigment particles will pile up on the printing plate or blanket during the ink transportation process, which will cause the roughness of the imprinting.
Third, do not distinguish between the role of anti-sticking agent and detackifier Adding anti-sticking agent in ink, can prevent or reduce the problem of sticky and dirty paper after printing. The detackifier is to reduce the viscosity of the ink, which is mainly used in the process of ink transfer during printing. If you confuse the two without distinction, it is likely that other problems will arise.
If the deinking agent is added to the ink in order to prevent the ink on the surface of the sheet from sticking, the "non-dry" nature of the de-bonding agent will prolong the drying time of the ink layer of the ink and adversely cause the sheet to stick and become more sticky.
On the other hand, if a better anti-sticking agent is added in order to reduce the viscosity of the ink in the printing process, it not only does not play a good role in viscosity reduction, but also causes the ink to "roughen" and lose its luster. Affect the quality of the product.
Fourth, do not pay attention to the difference between red oil and white oil Red dry oil (also known as cobalt dry oil) and white dry oil (also known as dry oil) are all desiccants of ink, but because of the composition of the two components are different The drying mode of the ink layer is also different.
The addition of red dry oil to the ink enables the surface of the ink layer to oxidize and consolidate at a significantly faster rate, ie, it rapidly dries on the surface of the ink layer, but the red dry oil does not promote the internal drying rate of the ink layer to be greatly improved. White dry oil has the property of promoting the overall drying of the ink layer. When the dry oil is added to the ink, the drying speed on the surface and inside of the ink layer can be greatly improved. Therefore, when using desiccants, we must pay attention to the difference between the two forms of drying. For example, for the ink surface drying, red oil is better than white dry oil. However, if the printing ink layer thicker solid version or paper due to pH relationship itself is not good drying performance of the ink layer, if the operator simply use the red oil as the ink desiccant, it is likely that the surface of the ink layer Dry but not very dry inside. Such prints, in the case of external force rubbing, can easily wipe off the ink layer so that the printed products have scratches and affect the quality of the product.
In addition, in the printing of gold ink, silver ink and the need to add desiccant, red kerosene should generally be used instead of adding white dry oil. Since white kerosene is combined with gold ink and silver ink, it tends to make the original ink darker, so that the print product will appear less bright and affect the gloss effect of gold and silver ink.