Use of confocal laser scanning microscopy and a computer model to understand ink cavitation and filamentation

A1 Journal article (refereed)

Internal Authors/Editors

Publication Details

List of Authors: Hanna Koivula, Douglas Bousfield, Martti Toivakka
Publication year: 2010
Journal: Tappi Journal
Journal acronym: TAPPI J
Volume number: 9
Issue number: 10
Start page: 7
End page: 15
Number of pages: 9
ISSN: 0734-1415


In the offset printing process, ink film splitting has an important impact on formation of ink filaments. The filament size and its distribution influence the leveling of ink and hence affect ink setting and the print quality. However, ink filaments are difficult to image due to their short lifetime and fine length scale. Due to this difficulty, limited work has been reported on the parameters that influence filament size and methods to characterize it.

We imaged ink filament remains and quantified some of their characteristics by changing printing speed, ink amount, and fountain solution type. Printed samples were prepared using a laboratory printability tester with varying ink levels and operating settings. Rhodamine B dye was incorporated into fountain solutions to aid in the detection of the filaments. The prints were then imaged with a confocal laser scanning microscope (CLSM) and images were further analyzed for their surface topography. Modeling of the pressure pulses in the printing nip was included to better understand the mechanism of filament formation and the origin of filament length scale. Printing speed and ink amount changed the size distribution of the observed filament remains. There was no significant difference between fountain solutions with or without isopropyl alcohol on the observed patterns of the filament remains.

Last updated on 2020-30-05 at 05:37