Deinking of Digital Prints:

Publications

Digitaldruck kämpft ums Ökoimage
(Artikel in den vdi nachrichten vom 26.10.2012)
Xeikon has published a white paper "Challenges in Recycling" that concludes a lot of the information about digital prints and deinking.

Digital faces clean-up test: Barney Cox reports about the different views about the environmental impact of inkjet and liquid toner (Indigo) prints
(PrintWeek 16 January 2009)

Inkjet inks and liquid toner are difficult to deink – dry toners do it better
A technical document by the "Technical Committee Deinking" is in German only as it is a statement of a German committee. One part of it deals with digital printing. The conclusion is a recommendation not to invest into liquid toner or inkjet technologies for production printing unless the deinkability questions have been solved. This document has been agreed upon with the German Printing and Media Industries Federation and other members of the paper chain in Germany who together with INGEDE have set up this "Technical Committee Deinking".

Informal English translation of the German text
Recycling – What can the printing industry do to make it easier?
INTERGRAF, the International Confederation for Printing and Allied Industries, has published a brochure about the "Recycling of Printed Products". INGEDE was not involved in this document. From about p. 29 you find a chapter on interactions with the deinking process. We do not share the opinion on specks from toner based prints, at least not for current production range equipment. This opinion must be based on some more historic SOHO printer based test. What we do share is the opinion on waterbased inks and inkjet inks.
INTERGRAF brochure (copy on INGEDE's server)

As a first result, the European Round Table has agreed on test files to allow deinkability testing of digital prints with a uniform pattern.

IJI 2004, Santa Barbara, USA: Presentation of Axel Fischer, INGEDE
(1.6 MB) (Members only)
INGEDE, some companies from the printer industry and CTP had formed a task force on the deinkability of digital prints. A summary of the work within the project has been presented by CTP at the PAPTAC Seminar 2004:

Digital Prints: A Survey of Deinkability (2004)

In 2001, INGEDE initiated a program to investigate the recyclability of digital prints. It resulted in a Task Force and a research project, supported by INGEDE and located at the CTP in Grenoble (France). Already the first tests showed that digital printing like Indigo or inkjet means a major problem for recycling – these inks cannot be removed during paper recycling.
At a workshop on October 18, 2001, at CTP the problem was discussed with a few representatives of the printer industry. The task force has been formed to monitor developments and investigate parameters that might lead to a better deinkability.

Summary of the Digideink Workshop (2001)

Industrial Scaleup of Enzyme-Enhanced Deinking of Nonimpact Printed Toners. Heise, Oliver U.; Unwin, Jay P.; Klungness, John H.; Fineran, William G., Jr.; Sykes, Marguerite; Abubakr, Said 1996. Tappi J. 79(3): 207-212.