4 Common water-based printing issues
If you are on a water-based printing operation or thinking about switching to a water-based printing operation, then you must understand the common water-based printing issues which include 1. Ink foaming 2. gelation 3. light ink color 4. and poor drying.
Ink foaming is a common issue in water-based ink as the ink uses mostly water as its solvent. The bubbles in the ink will cause white spots, sand holes and water marks on the final printed image. This foaming issue is mainly due to the insufficient ink flow on the anilox, too much water within the ink or too much pump circulation causing excess air getting into the ink. The solution to this issue is to change the anilox to an open cell shape anilox to allow a better ink flow. To add an appropriate amount of defoamer to reduce foams. To reduce the circulation frequency of the pump to prevent excess air from entering the ink.
Ink gelation is the solidification of the ink from fluid to solid due to improper storage or improper adding of ink additive and solvents. The solution is to keep the ink tightly closed in the container and to keep it under a cool controlled temperature.
Light ink color
The ink color is light, and the graphic tone is dim and not bright. This issue is likely caused by the lack of ink transfer from the anilox to printing roller and from printing rollers onto the substrate. A common issue of water-based ink is the unsatisfactory ink transfer onto the substrate due to low substrate dyne level. A printer needs to pay much attention to the transfer issue especially when working with water based ink on film substrates.
Drying issues can be a headache for water-based ink as the ink is harder to dry on non-porous film substrates. Turning up the heat too high can cause the substrate to overheat and get damaged. Turning the heat too low can cause undried ink on the substrate. A solution is to use a non-heat dependent drying solution: NIR. NIR drying process that does not heat up the substrate during the drying process, therefore eliminating the issue of overheating.
To understand what you are up against when using water-based ink will prepare you for the operation. There are obstacles to reaching a decent printing result with water-based ink. However, if you can overcome these obstacles, water-based ink is a more eco friendly printing process when compared to solvent based ink and it is expected to become the main trend in the near future.