Thin film printing produces ripples or vertical stripes

Wrinkled thin stripes or longitudinal stripes on large area prints are caused by too thin ink and low viscosity. We require that the ink be transferred from the printing roller to the substrate to be printed. It can be immediately fixed on the film and no longer be displaced by the movement of the film. This requires the ink to have a certain viscosity so that it must not be moved. The tack force makes it possible to adhere to one of the substrate films by contacting it. If the ink is too thin, it is easy to flow, and the initial tack is not enough. Under the high-speed operation of the film, the ink transferred to the film will be displaced by the centrifugal force generated by the high-speed movement 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.

Excerpt from: China Packaging News