Inkjet & Digital Printing
DPDA confirms successful deinking of inkjet printed paper at international scientific symposium
Thursday 17. June 2010 - Research by Digital Printing Deinking Alliance shows encouraging progress in technology recycling
Océ, an international leader in digital document management and delivery, today announced that the Digital Printing Deinking Alliance (DPDA) shared the first of a series of scientific research investigations into the deinkability of inkjet printed papers at the PTS Deinking Symposium held recently in Munich, Germany. Océ is a member of DPDA.
Deinking inkjet prints
In a study conducted by a leading research organization and expert in the field of recycling technologies, Centre Technique du Papier (CTP) of Grenoble, France, inkjet prints were successfully deinked in a procedure designed to replicate a typical European mixed grade waste paper recycling system.
Presenting on behalf of the DPDA, Gary Williams, PE, Paper Scientist of InfoPrint Solutions Company, reviewed the CTP research data with leading industry experts gathered at this international Deinking Symposium. “Our first study was intended to prepare a baseline for future testing of inkjet prints. We were pleasantly surprised to learn that all samples proved to be successfully deinked in test conditions that included bleaching,” said Williams.
Encouraging results
The test samples were printed using standard aqueous dye-based inkjet inks on uncoated woodfree paper. DPDA members prepared blind samples using three representative dye-based inksets for the study and tested under conditions designed to be representative of current deinking technology for processing mixed grades of recovered paper. In the study, all colorants tested were successfully deinked when hydrosulphite bleach was added after the repulping process. In one case, ink colorants were successfully deinked using peroxide only, which is a typical chemistry used in virtually all repulping systems. In both cases, the bleached pulp met the deinked pulp quality requirements.
“This is very encouraging as a first study,” said David Hatfield, R&D Manager for Kodak. “It provides some fact-based data that confirms what we have believed from over 40 years of inkjet printing. Most commercial recycling systems are robust and we have yet to observe a failure in any recycling system worldwide.”
Why INGEDE Method 11 does not match
It has been recently suggested that inkjet printed papers are not deinkable according to laboratory test conditions known as INGEDE Method 11. This lab test was originally conceived to compare the deinking performance of offset printed newspapers. INGEDE Method 11 is sometimes cited as a simple lab-scale test to compare deinking performance of various printing technologies. “Method 11 is not appropriate for all aqueous-based inks, since the test is primarily a single step flotation test. With dye-based inks, there is no ink particle to float, hence the futility of trying to meet this requirement,” said Dr Matthias Fromm, R&D Manager for Océ Printing Systems. “We wanted to test using conditions that replicate actual recycling systems and understand the impact of inkjet printed papers in these commercial recycling systems. This research was conducted using 100% inkjet paper. We estimate that production inkjets market share of total graphic printing is less than 1% today. Based on the growth potential of inkjet printing, we estimate that there remain a couple of years to jointly develop a concerted system of paper, ink and possibly adapted deinking process resulting in a good deinking performance,” said Fromm.
Tests to be continued
According to Gregg Lane, Sr Chemist at HP, “DPDA research will continue with other types of inkjet inks and paper combinations. It is important for the DPDA members that we work collaboratively with INGEDE and the paper industry. The benefits of inkjet printing are tremendous and it will penetrate many offset printing markets such as publishing and direct mail, bringing with it the reduced carbon footprint of print-on-demand solutions. As corporate stewards for inkjet printing technology, the DPDA member firms are investing significant technical resources to ensure that the full value of inkjet printing – both print and environmental performance – can be realized,” said Lane.