There is a large area of ​​water streak in the print (film advance direction). Why?

The large-area print with corrugated thin stripes or longitudinal stripes is caused by too thin ink and low viscosity. We require that the ink be transferred from the platen roller to the substrate to be printed and it can be immediately fixed on the film and no longer be affected by the film. Displacement occurs due to the movement of the ink, which requires the ink to have a certain viscosity to make it difficult to move, and to have a certain initial tack force, so that one can contact the substrate film to stick to it. If the ink is too thin, easy to flow, and the initial tack is insufficient, the ink transferred to the film will be displaced by the centrifugal force generated by the high speed movement during the high speed operation of the film to form a watermark stripe.

The solution is: the viscosity of the ink should be between 16-25 seconds (3 # zahn cup), and the amount of ink binder should be appropriate to improve the initial viscosity of the ink. However, the viscosity of the ink is too large and it also causes streaks. This kind of streaks is dry and should be distinguished. Watermarks printed under the magnifying glass do not see the mesh. (China Packaging News and Printing Weekly)