While some digital printer manufacturers still fiddle about the methodology of recyclability tests and the paper industry’s deinking process*, others have already done their homework: At the IPEX 2010 fair in Birmingham, for the first time two different inkjet printing systems are shown which inde-pendently of each other deliver good deinkable printed prod-ucts. Xerox’s production inkjet technology is currently the only one that without applying costly pre-coating materials to the paper receives “good” deinkability according to the ERPC Deinkability Scores**. The highest possible rating “good deinkable” with even better detailed results is also achieved by prints from Fujifilm’s Jet Press 720, a B2 sheet-fed digital inkjet press.
These systems use totally different approaches to end up with good deinkability: One does completely without water soluble pigments or dyes but sputters melted, hydrophobic ink to the paper which does not dissolve during paper recy-cling. The other process uses some kind of binding agent which is applied to the paper immediately before the ink. It fixes the originally water based pigments so well, that they can be removed as larger particles later. A similar system had been shown by HP at drupa 2008 but samples of the currently available final product do not fulfil the deinkability criteria yet.
Result of a Consistent Dialogue
Before drupa 2008 INGEDE had pointed at problems in re-cycling the prevalent inkjet prints. While dry toner prints are generally good deinkable, with inkjet prints this works only on a few special papers. “Like a red sock in a washing ma-chine with white laundry, prints with water soluble dyes or pigments can make a whole load of recovered paper useless for recycling”, explains Axel Fischer, chemist and INGEDE’s expert for recycling digital prints. “The recent developments are a nice acknowledgment for the consistent dialogue of the paper industry with the digital printer manufacturers which we lead for a couple of years now. They also show that it is actually possible to design inkjet prints in a way that they work well in the existing system of paper recycling. For the future, we can expect more positive development in this sector.” At a symposium in Munich in April, the Japanese
chemical company KAO had presented a third approach – a pigment which by special encapsulation also leads to good deinkable print results.
With all three systems, good deinkability goes hand in hand with better image quality – these inks tend to less bleeding and less strike through.
INGEDE is an association of leading European paper manu-facturers founded in 1989. INGEDE aims at promoting utili-sation of recovered graphic paper (newsprint, magazines and office paper) and improving the conditions for an ex-tended use of recovered paper for the production of graphic and hygiene papers.
* Deinking is the removal of printing ink from the recovered paper during the paper recycling process.
** ERPC is the European Recovered Paper Council. The “Deinkability Score” system is available from the ERPC web-site www.paperrecovery.org.
Source: www.ingede.com
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