Uneven corona treatment (bands or untreated zones)
High severitySymptoms
Good adhesion in parts of the sheet, poor in others; visible bands with test ink
Probable causes
- Dirty or worn treater electrodes
- uneven electrode-roller gap
- damaged dielectric roller
- high ambient humidity stealing the discharge
The Print Guy · 2026-10-05
Other problems in this category
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-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