Printing Flaws

Flexographic Plates Troubleshooting: Problems, Solutions and Causes – Part 3

This is a continuation to the series of flexo plates troubleshooting Part 1 and Part 2. Hyperlinks have been added here, in case you have not read the previous articles.

Blocking

  • Problem: Ink transfer from one print to the next
  • Causes: Ink drying problems; web tension issues; substrate humidity problem
  • Solutions:  Optimisation of ink, substrate and dryer parameters
© Mary Anne Enriquez

Ink splashing

  • Problem: Ink splashing
  • Causes: Ink viscosity too low; wrong anilox specification (volume too high and/or line count too low)
  • Solutions: Correct ink viscosity; optimize anilox specification
© Anyflexo
© Anyflexo

Registration issues

  • Problem: Registration problems in print
  • Causes: Issues during plate mounting; equipment problems during plate making (drying unit); plate orientation on imaging system; separations made from different raw material batches
  • Solutions: Confirm functionality of plate making equipment; image separations in the same orientation on the CDI; use plates for different separations from same raw material box/batch
© Anyflexo

Element edges start to print earlier

  • Problem:: Element edges start to print early
  • Causes: Cupping issue; high anilox to plate or plate to substrate impression
  • Solutions: Optimisation of plate making parameters (especially dry times); optimisation of impression settings on press
© Anyflexo

“Unsharp” printing

  • Problem: Unsharp printing result; high dot gain
  • Causes: Excessive plate swelling from unsuitable solvents or cleaners could result in plate softening during printing; high impression settings; possibly “cupping” issue; possibly ink issue
  • Solutions: Confirmation of suitable solvents; possibly reduce impression settings
© Anyflexo

Ink transfer issues

  • Problem: Ink transfer issues
  • Causes: General ink issue; ink drying on the anilox roller; plate surface contaminated
  • Solutions: Confirm the condition of the ink; cleaning of plate surface and anilox roller
© Anyflexo
Proper Ink Transfer
© Anyflexo
Defective Ink Transfer

“Filling in” of fine elements

  • Problem: Fine printed elements start to fill in with ink
  • Causes: High anilox to plate impression; wrong ink viscosity
  • Solutions: Confirm anilox settings; check and correct ink viscosity
© Anyflexo

Ink “bleeding”

  • Problem: Ink starts to bleed; no defined screen structures visible
  • Causes: Improper pigment use in ink formulation; pH issue in water based ink formulation
  • Solutions: Consult your ink manufacturer
© Anyflexo

“Dirty printing” in transitions of flexo plates

  • Problem: Screen transitions start to print dirty
  • Causes: High anilox to plate impression setting; low ink viscosity; high anilox volume; shallow intermediate depths or plate relief
  • Solutions: Optimisation of press and ink parameters, correction of plate making issues
Flexo plates problems and solutions. © Anyflexo