NextJet

The project "Next Generation Paper Substrates for Inkjet Printing" is part of a research program that aims at controlling print quality by understanding and controlling the dynamic processes and interfacial actions that occur as ink jet ink impedes on paper media in the printing process.

Due to the complexity of the inkjet printing process, researchers have usually focused on individual sub-processes occuring within a particular liquid-substrate system. Droplet spreading in model systems has been investigated and absorption (penetration) of liquid in porous media has been studied experimentally and by computer-modelling. There is a need to address the combination of processes that yields the final print. A major challenge is the improvement of experimental tools needed to capture important parts of the printing process in order to assemble data for further analysis. Fundamental aspects of inkjet receptive coatings continue to receive a lot of attention. YKI has been active in this field, both on wetting and penetration phenomena in uncoated and coated papers, material development of pigments, characterization of inkjetted uncoated papers by microscopy and spectroscopy.

One of the most recent investigations on the material side is on tailor-made pigments which carries pore structures both in the meso (2-20 nm) and micrometer scale. The combination of pores of different length scales gives extra possibilities in terms of achieving capillary flow of ink to a micrometer void and also in terms of understanding basic inkjet mechanisms in uncoated papers, in which the size distribution, pore structure and surface chemistry of pores is much more complex compared with coated inkjet papers. One aim of this project is to close the performance gap between uncoated (or surface treated) papers and fully coated inkjet papers.

The possibility to study, in detail, the dynamics of ink jet ink droplets on paper media under realistic printing conditions is mainly due to the establishment of a unique high speed ink jet rig equipped with a high speed camera at DPC. In collaboration with the paper industry, pilot paper where one parameter can be systematically varied in the paper production process is accessible. In-situ studies of liquid dynamics in the inkjet printing process have been carried out for oil based ink, and a printing system for water based ink has been installed and tested. Moreover, pigments with tailor-made pores of controlled size and surface chemistry open up for the possibility to study liquid dynamics on model surfaces.

Milestones/Results
• Understand the mechanisms of inkjet droplet spreading and absorption as the ink jet
   droplets impede on paper media under realistic printing conditions
• Control these mechanisms by modifying the paper surface in the paper making
   process
• Further develop uncoated inkjet paper to close the performance gap to coated inkjet
   papers
• Further develop pigments and control interfacial phenomena for coated papers to
   achieve photo quality
• Predict some of the future restrictions and possibilities of inkjet printing by
   experimental and theoretical investigations of the influence of print production
   parameters.


Collaboration

  • Digital Printing Centre at Mid-Sweden University
  • Industry partners in paper, pigments and inkjet
  • Kempe Foundation
  • STFI-Packforsk
  • KTH Department ofMechanics

 

 

SP Chemistry, Materials and Surfaces, Box 5607, SE-114 86 Stockholm, Sweden Phone +46 10 516 5000, E-mail info@sp.se