Blocking:

Possible Causes:

Solution:

  • Ink is drying too slow
  • Use faster drying solvents
  • Decrease the printing speed
  • Increase air flow and temperature of blower.
  • Rewind pressure is too high
  • Decrease the rewind pressure
  • Over plasticized inks
  • Contact ink supplier.
  • Add anti-blocking compound.
  • Film is treated on both sides
  • Use one side treated film; or
  • Use anti-blocking compound.

 


 

Dot Bridging:

Possible Causes:

Solution:

  • High plate impression
  • Check and reduce plate impression.
  • Excessive ink is transferred to the plate
  • Reduce anilox volume; and/or
  • Check doctor blade.

 

 

Adhesion:

Possible Causes:

Solution:

  • Poor treatment of substrate
  • Treat substrate to appropriate treatment level
  • Improper ink for the substrate
  • Contact ink supplier and request for the right ink for the substrate.

  

 

Halo around print:

Possible Causes:

Solution:

  • Excessive impression pressure
  • Adjust to “kiss” impression

 

  

 

Ink Smearing:

Possible Causes:

Solution:

  • Previous ink is not fully dried
  • Adjust the previous ink by:

    - Reduce viscosity

    - Use faster drying solvent

    - Increase blower volume and     temperature.

 


Screening:

Possible Causes:

Solution:

  • Ink is fast drying and drying up in the anilox roll
  • Use a slower drying solvent
  • Not enough ink going into the anilox cells
  • Reduce press speed; or

    Reduce ink viscosity to allow faster entry of ink into the anilox cells.