Practical experience in label printing: "Uneven color dropouts"

Practical experience in label printing: "Uneven color dropouts"

03.03.2016

In our series "Practical experience in label printing," we address everyday challenges in label printing and how to solve them. In this issue, we focus on the topic: "Uneven ink coverage."

Problem identification:
Unevenly bright shadows and color dropouts appear in the print image, caused by air trapped in the anilox roll cells. The problem occurs more frequently with metallic colors and chamber blade flexographic printing units.

Troubleshooting:

• Reduce paint viscosity
• Lower the color level in the color chamber
• Increase the flow of paint in the paint tray by continuously pumping it around (= create circulation in the paint tray).
• Reduce machine speed
• Change color series
• Use Gallus anti-stencil form for ink chambers
• Gallus EM280: The diameter of the dip roller is too small (target: 60.9 mm). If the
  If the diameter falls below 60.0 mm, the immersion roller must be replaced.