Modelling Ink Transmission from Local Paper Properties

 

Print quality demands are steadily growing and several print quality problems (e.g. print mottle) are known to be closely related to specific paper properties. The objective of this project is to understand the paper related reasons for print unevenness and missing ink transmission (Fig.2).  For this purpose overall paper parameters like PPS roughness, formation index, brightness, etc. are usually measured.

In this work we will quantify the combined contribution of local paper properties to print unevenness and missing ink transmission. The key approach is to reveal the local paper properties which produce a local defect of the print.

        Fig.1: even print image                                   Fig.2: missing ink transmission

 Materials & Methods

Local measurement of the relevant paper properties connected to print unevenness and missing ink transmission is crucial in this project. Several local high resolution measurements of paper properties were developed and several commercially available methods were evaluated. 

  • Brightness (Scanner, IFM)

  • Opacity (Scanner, IFM)

  • Basis Weight (BETA Formation)

  • Topography (IFM, UST)

  • Ink Penetration (Scanner, IFM)

  • This measurement method has been developed within this project and gives information about the ink penetration on inkjet printed paper grades.

  • Thickness Variation (IFM)

          • Thickness variation can be calculated when measuring the topography of the front and back side of a sample.

  • Light Scattering (Scanner, IFM)

  • Topography under Load (PST Fibro)

  • Coating layer distribution ( UV Scanner)

          • A method for fast evaluation of spatial coating layer formation using UV scanner imaging has been introduced within this project. Therefore, the FWA, usually contained in the coating colour is used as an internal marker. Hence, the FWA distribution is related to the spatial conating layer distribution.

 

The focus is set on new printing technologies:

  • High Speed Inkjet Printing

  • Xerography (i.e. photocopying technique)

furthermore it is of interest to pursue the previous research on:

  • Offset Printing

  • Rotogravure Printing

  • Flexography Printing

 

 

 Industrial Partners

  • Andritz Pulp & Paper

  • BASF

  • Mondi Uncoated Fine Paper

  • Mondi Frantschach

  • Omya

  • Sappi Gratkorn

  • Stora Enso

  • Océ

Contact

HIRN, Ulrich, Ass.Prof. Dipl.-Ing. Dr.techn.

FUCHS, Wolfgang, Dipl.-Ing.

 publications

All publications can be found here.

Projectduration

February 2013 - May 2016