In the process of UV offset ink printing, the operator's most headache is string color. This problem is generally caused by improper printing color sequence, printing pressure is not adjusted to a better state, UV offset ink liquidity is too large. In order to solve the UV ink string color problem, I suggest starting from the following two aspects.
Reasonable adjustment of printing pressure: in order to solve the problem of string color in UV ink printing process, the adjustment of printing pressure is also very important. For example, the pressure between blanket cylinder and plate cylinder must be adjusted to the standard pressure range; Blanket better use of UV printing special blanket; The key color group adopts independent UV curing device.
Reasonable arrangement of printing color sequence: when the proportion of each color in the printed pattern differs greatly, the phenomenon of color string is most likely to occur. In this case, the color sequence should be appropriately changed according to the actual amount of printing ink. You can print colors with less ink first and then colors with more ink. Can avoid color to cross phenomenon effectively not only so, still can make vamp ink quantity is bigger change, color is fuller.
How to solve the problem of insufficient adhesion of UV ink?
When printing on some non-absorbable substrates such as gold and silver card paper, UV ink curing time is short, sometimes UV ink adhesion to substrates is low. Insufficient adhesion of UV ink will have a great impact on the printing quality and subsequent processing of the product.
To solve the problem of insufficient adhesion of UV ink, the usual measure is to corona treatment of substrate, change its polarity, increase the combination of UV ink on its surface, so as to improve the adhesion of UV ink. If through verification found that the problem of UV ink adhesion is not caused by substrate and UV ink curing quality, then you can consider whether it is the quality of UV ink itself.
What are the special requirements for UV ink application?
Requirements for printing equipment: At present, many printing enterprises through the installation of UV curing equipment on the ordinary offset press to achieve UV printing. However, there are many problems in this way of equipment transformation. For example, UV ink has a strong corrosive, will cause ordinary cots, blanket expansion, affect the stability of printing pressure, serious even cause cots peeling or surface cracking.
Ordinary gripper under ultraviolet radiation will be thermal deformation, affecting overprinter accuracy. Therefore, the gripper on the printing unit must be replaced with a special gripper for UV printing.
UV ink high viscosity, strong corrosion. Not only ordinary ink bucket is easy to crack and damage, resulting in UV ink into the ink wheel drive mechanism, resulting in ink wheel drive motor failure due to excessive resistance, rubber roller adjustment mechanism and ink wheel swing mechanism are also vulnerable to damage. Operators are required to strengthen the daily maintenance of printing equipment, clean it thoroughly, and use qualified accessories and raw materials.
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