Peter Rättö, Erik Blohm, Gary Chinga-Carrasco
The filament pattern during printing was studied. The printing was performed in a Prüfbau laboratory printing press with IGT medium viscosity oil. The filament pattern was recorded with a high speed camera. Newsprint handsheets with similar surface roughness but different amounts of fine material were used during the trials. Different amount of fine material was obtained by fractionising the TMP pulp and additional beating of kraft pulp. Both qualitative and quantitative analyses of the filament pattern were performed.
The filament pattern at the nip exit appeared as a bright area. The density of the filament pattern was further analysed with computerized image analysis. The intensity and spreading of the brighter area were quantified. An increased amount of fine material resulted in a denser filament pattern. Calendering densified the filament pattern further.
A dense filament pattern indicates a later oil splitting point from the nip centre and a higher splitting force due to a higher splitting velocity. A dense and smooth paper would thus be subjected to higher tensional forces at the nip exit than a porous and relatively rough paper.
Keywords: film splitting, ink film, porosity, roughness, printing
The International Association of Research Organizations for the
Information, Media and Graphic Arts Industries
- Order here
- About iarigai
- Conferences & Events
- 2011 Budapest
- 2010 Montreal
- 2009 Stockholm
- 2008 Valencia
- 2007 Grenoble
- 2006 Leipzig
- 2005 Porvoo
- Former Conferences