Recognising a worn-out covering
Glazing
Ink build-up and calcareous deposits or residues that resist careful washing and cleaning.
Hardening
A surface hardness increase exceeding 5 Shore A compared with the new roller cover.
Surface destruction
Porosity, roughness, break-ups — especially at the ends — irregular abrasion, orange peel effect, material tears and sore running.
Dimensional deviation
Cigar shape, trumpets at the ends, collar build-up at the edges, shrinkage or swelling.
Heavy diameter shrinkage
Actual diameter deviating by more than 1.0 mm from the new roller specification.
Faults from incorrect cover treatment
Washing too frequently
Shortened service life, through separation of material particles and excessive chemical stress.
Insufficient washing, cleaning and maintenance
- Filling-in, glazing and hardening of the roller surface
- Bad ink splitting
- Reduced ink storage, with danger of ghosting or streaking
- Enhanced plate wear or pollution from loosened ink residue
- Linting and fluffing
Aggressive or wrong washing agents
- Swelling or shrinkage, which changes the setting
- Cover dissolution or rapid abrasion
- Surface hardening or glazing
Inadequate inks, UV inks or lacquers
- Setting changes from swelling or shrinkage
- Surface hardening or glazing
- Cover dissolution or rapid abrasion
Dry running and reduced transport areas
Running dry at the ends, or over a reduced transport area — a web narrower than the face length — produces a characteristic cluster of faults:
- Premature glazing from ink drying
- Axial and radial crack formation
- Partial cover picking
- Marks in the printed image
- Locally enhanced hickie accumulation
- Local overheating
Calcareous dampening water
- Surface filling and glazing from calcareous deposits
- Ghosting and streaking
- Enhanced printing plate wear
Handling and storage faults
Cleaning with sharp objects
Using a spatula or wire brush causes mechanical damage and scratching, resulting in hickie accumulation, loosened rubber particles, pollution of the printing form and marks in the print.
Storage without sun and ozone protection
- Surface glazing
- Embrittlement and crack formation
Storage lying on its side
One-sided deformation and loss of dimensional accuracy. Store on the journals, never on the cover.
