HP Indigo troubleshooting – Ink Adhesion

Q. How do I improve the ink adhesion to FlexBind® photo pages?

A. All FlexBind® products have been RIT certified to run on an HP Indigo Press.  Follow the few steps below to optimize adhesion.

Ink adhesion defects are typically broken into 2 categories, poor tape adhesion and picking.

Tape Adhesion Test Failure

Failure of the Tape Adhesion test is not a common occurrence with FlexBind and is typically related to a press setting.  All FlexBind products are RIT certified and have at least 2 stars for ink adhesion.  To improve ink adhesion, there are adjustments to the HP Indigo press and to general handling procedures.

  1. HP recommends a maximum of 280%  total ink coverage.  Often, printers will exceed 300% ink coverage to improve the density of colors.  Special care should be taken when printing dense ink coverage.
  2. Incorporate a hold time after printing to allow the ink to adhere to the surface.  12 hours is best, but 2 hours will also show some improvement in adhesion.  Many of the processes in binding are aggressive on the printed surface.
  3. Reduce the clamp pressure on the guillotine cutter.
  4. Be sure that the gap is properly set for the book block thickness when side-stitching or side-sewing.  Some printers will reduce the gap on their side-stitcher so that the staple is slightly compressed into the sheet.  While the effect may be more desirable, the impact of the stitcher on the book block is severe.
  5. Change the impression paper.  Residual ink built up on the impression paper can have a slight amount of tack when heated, thus pulling at the print when duplex printing the second side.
  6. Run a Level 1 and 2 Null Cycle.  The press output will be reduced because the paper makes an extra revolution before exiting.  Click here for a chart explaining Null Cycles.
  7. Run the press in Heavy Substrate mode.  Sometimes tiny areas of picking are really ultra-fine scratches caused by sheets rubbing against one another during duplex printing.  This will reduce the output of the Indigo press.
  8. increase the blanket temperature by 5 degrees to drive off residual carrier solvent from the inks.
  9. Reset the ITM temperature
  10. Clean the ITM sensor
  11. Clean the bias brushes on the ITM
  12. Calibrate the density and and conductivity of the inks.  This can only be done by an HP technician.