Abstract
In offset printing unit the interaction between ink,
blanket and paper surface defines adhesion of the web on
the blanket surface. After ink transfer paper web follows
the blanket surface at the nip exit until it is released
due web tension. The adhesion of the web depends on the
surface properties of paper, printing material
combinations, the layout and press settings. In general,
shorter follow-up of the web on blanket surface predicts
easier release thus longer follow-up can lead to higher
release angle. The purpose of this study was to clarify
the factors (material and process parameters) controlling
paper web's release from the blanket. The release of six
various paper grades was followed. Other studied
variables were the release property of blankets and the
influence of ink tack on web release. Furthermore, during
printing the effect of fountain solution feed and nip
pressure on web release was examined. The release force
between printing materials was first studied in
laboratory and the verification was carried out in
full-scale heatset printings. On printing press the
release of the web was measured using release angle
measurement arrangements. Furthermore, an acoustic signal
was gathered from ink film splitting to describe the web
release. According to results, paper grade determines the
level of web release angle. The results indicate that the
smooth paper surface induces strong adhesion on the
blanket which leads to higher release angle. Furthermore,
the surface structure of the paper and the speed of ink
absorption affect web release. In addition, it was noted
that small amount of accumulated material on blanket
surface easies the web release. According to studies, the
release angle of the web can be lowered by selecting easy
release blanket, lower ink tack, higher fountain solution
feed and lower nip pressure.
Original language | English |
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Title of host publication | Proceedings |
Subtitle of host publication | PTS Coating Symposium 2013 |
Place of Publication | München |
Publication status | Published - 2013 |
MoE publication type | B3 Non-refereed article in conference proceedings |
Event | PTS Coating Symposium 2013 - München, Germany Duration: 18 Sept 2013 → 18 Sept 2013 |
Conference
Conference | PTS Coating Symposium 2013 |
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Country/Territory | Germany |
City | München |
Period | 18/09/13 → 18/09/13 |
Keywords
- heatset
- web release
- adhesion
- on-line monitoring