Guidelines for Using DigiPrime® 050 for HP Indigo 20000 Presses

Substrate Selection Guide

Please refer to HP validated materials for more updated information or contact Michelman.

  • Films: wide variety
  • Paper

Packaging

DigiPrime® 050 is available in pails of 18Kg.

STORAGE OF LIQUID DIGIPRIME® 050

DigiPrime® 050 is a water-based, press-ready primer. It is very stable, with a shelf life of 12 months if stored unopened at moderate temperatures above 5°C. The primer must be protected from freezing. If frozen, it is possible that grit or gels may be found in the product and it should not be used.

 

Primer in the In-Line Priming Unit

Quantity of Primer and Cleaning Solutions

In the priming unit on the HP Indigo machine, you will find space for 2 pails of 18 liters each. One tank should be filled with deionized water, the second one should be filled with primer (DigiPrime® 050).

The new PUW cleaning cycles prevent primer for drying on the coating roller and anilox. If the primer happens to dry and forms an insoluble film for any reason, use IPA or hot water to remove the dried primer from the coating roller or anilox. Never use any other cleaning agent. If you want to use a cleaning agent, please contact Michelman.

Press Settings

For successful priming of your substrate and good adhesion of the ink, it is important to follow HP recommendations about the PUW settings and check the following parameters:

  • Corona settings
  • Coating: amount of primer applied (low, medium, or high)
  • Drying instructions
  • Cleaning cycle
 

Please refer to HP “How-to Guide”

Illustrating the water and primer pail set up.
 

Recommended Coat Weight

SubstrateTarget Dry GSMAnilox Type

film lamination structure

0.14 - 0.18

220l/cm/5.23cm³/M²

single film or pre-laminate

0.08 - 0.10

220l/cm/4.09cm³/M²

 

Quality Check

 
Checking the Primer Adhesion

Use a combination of Michem® Indicator MI102 solution and the tape test:

  1. Apply tape (3M Scotch 234 for paper, 3M Scotch 810 for film) smoothly to the primed surface without wrinkling.
  2. Apply sufficient pressure using a 2Kg roller evenly along the tape. Run the roller back-and forth two times.
  3. Wait 20 minutes before peeling the tape. After removing tape, check substrate surface for primer removal.
  4. Verify presence of primer by applying the above mentioned primer indicator in the peeled area. If there is primer adhesion, it will change appearance from yellow to blue.
Checking the Ink Adhesion
  1. Ink Adhesion can be verified with the same method used to verify primer adhesion (FINAT FTM21).
  2. Wait for 15 minutes after printing before applying tape to the printed surface.
  3. Wait 20 minutes before peeling the tape. After removing tape, check substrate surface for ink removal.
  4. Result should be 86% of the ink adhesion (3 star level).
Illustrating the primer adhesion.

Published on: April 3, 2023