Polyboard/Corona problems: causes and fixes
14 Polyboard/Corona problems in offset printing and finishing: symptoms, probable causes, step-by-step fixes and prevention.
Polyboard/Corona · TPG-119
Ink won't adhere on polyboard (PE)
Ink scratches off with a nail or lifts with tape; image 'floating' on the surface
Polyboard/Corona · TPG-120
Corona treatment decays over time
Stock that printed fine weeks ago now rejects ink; dynes lower than the supplier declared
Polyboard/Corona · TPG-122
Uneven corona treatment (bands or untreated zones)
Good adhesion in parts of the sheet, poor in others; visible bands with test ink
Polyboard/Corona · TPG-123
Slow or no ink drying on polyboard
Ink wet for hours or days; massive set-off; job can't be finished
Polyboard/Corona · TPG-124
Set-off and blocking in the pile with polyboard
Sheets stuck together; ink transferred to the PE face of the next sheet
Polyboard/Corona · TPG-127
Curl of single-side-coated polyboard
Sheets curling toward the PE side at the feeder or after printing; registration and feeding impossible
Polyboard/Corona · TPG-128
Blocking of fiber side against PE side in the pile
Ink printed on the fiber side transfers to the PE side of the sheet above; stuck sheets
Polyboard/Corona · TPG-130
Finishing on the PE side (coating, lamination, hot foil)
Coating crawls, laminate delaminates or foil won't transfer on the polyethylene side
Polyboard/Corona · TPG-131
Die-cutting and creasing polyboard
Cuts with PE 'hairs' or strands; creases that don't break cleanly; PE stretching instead of cutting
Polyboard/Corona · TPG-132
Printing both sides (fiber + PE) of polyboard
The second side fails although the first ran fine; adhesion or registration lost at the turn
Polyboard/Corona · TPG-121
Corona over-treatment
Surface blocking in the pile, odor, coating migration, or adhesion getting worse instead of better
Polyboard/Corona · TPG-125
Severe static with polyboard
Sheets sticking at the feeder, constant doubles, shocks to staff, dust attracted to the surface
Polyboard/Corona · TPG-126
Wrong side treated or printed (1-side / 2-side polyboard)
Perfect adhesion in tests but failure in production; PE and fiber sides confused
Polyboard/Corona · TPG-129
Local treatment loss from handling
Zones where ink won't stick shaped like fingers, hands or rub bands; the rest prints fine