Six common technical problems and its solutions in the process of UV ink printing

1)   Adhesion

Because of the poor osmosis and adhesion of plastic films and gold&silver cardboard, it may affect the quality in the process of UV ink printing. Can be solved via surface treatment of these films.

2)   Degree of cure

If want to get high chroma of the presswork, we need to put printing pressure up in the process of UV printing on the surface of plastic sheet and etc. as a result, the ink layer get thicker, the dot increase, which makes ink not easy to cure. In order to ensure the quality of printing, printing pressure can not change, there are two ways to replace: first, reduce the printing speed appropriately, make the UV-LED equipment irradiation time longer; second, adjust the gap between the equipment and the substrates, increase the intensity of UV ray irradiation, make  ink cure successfully. Effective wavelength of UV curing is 200-400nm, including light source in the workshop. This can make ink surface cured slightly, so please pay attention to the influence of ambient light on UV ink.

3)   Printing registration

Curing process of UV offset ink using UV-LED curing equipment, may make substrates heated, then expand, causing misregister in the end. There is contradictory between Ink curing and printing registration at first, because ink curing need UV-LED curing equipment to irradiate for a long time, while printing registration in the opposite side. Solution: UV curing process happens after the last color printed on the substrate, this can Reduce the temperature by placing a period of time, and minimize the deformation of substrate. In particularly, halftone can be irradiated using UV-LED curing equipment, but keep time as short as possible. Or using Cold UV Technology.

4)   Color sequence

It may be a little complex. Limited by inking principle, the ink layer what we got is thin, but if need thick layer, the print effect of substrate hard to reach desired. For example, in the process of four-color overprint, we used to bring black, cyan, magenta, yellow as a color sequence, however, black filled almost all space, the inking ability of other three get lower and lower, lead to chromaless for lack of ink at last. The solution is change the color sequence what we used to, print small amount of color ink first, black at last. Then increase inking ability, get good chroma.

5)   Ink emulsification

It is difficult to keep ink-water balance in UV Ink, ink emulsification and scumming often happen, which can affect printing quality. Solution: reduce printing speed, keep it within 5000-8000 times/h.

6)   Plate making design

Output format of UV printing designs depends on order. For example: the sweep or reverse sweep of film surface, the count of output reticles, the degree of reticles. Some special printing materials demand higher, such as 3D printing demands higher resolution, the degree of reticles and substrates must be matched to avoid moire. often need to print white ink on Transparent plastic substrates and aluminium-plating paper, please mind the flex influence of printed materials, adjust the films to reach a best quality in advance.