A Hurdle to High Speed Inkjet Supremacy Writ Small

The ascendancy of production inkjet may be written in disappearing ink…or not.

by Sean O'Leary
There is a speed bump dogging the supremacy of inkjet technology like trouble dogs River City. We’re talking about de-inking. That is to say, “pulp laundering”, the key component of the recycling process in which ink residue is washed and filtered out of incoming paper stock. The problem is that aqueous inkjet formulations are difficult to completely remove from paper pulp and that can mess up the whole process.

Technically speaking, the reason for this is as follows: “hydrophilic pigments and soluble dyes do not agglomerate to suitable particle size for the dominant separation method, i.e. flotation, but dissolve or form too small pieces which remain in the liquid phase or adhere on the fiber surface causing deteriorated brightness.”

That excerpt is from a 2012 patent application for a deinking method. It is basically saying the dye particle sizes are too small to filter or float. Dye inks are soluble and don’t latch onto air bubbles and float to the surface of a de-inking tank. A fairly small percentage of inkjet-printed stock – from 5 to 10% from what I read - can contaminate an entire batch of mixed papers.

Even though it is decidedly unsexy compared to the sleek inkjet platforms you’ll be seeing at drupa, de-inking is a technically challenging undertaking. It has taken a lot of time, expense and infrastructure to develop today’s reliable deinking and recycling methods. It has also required a lot of collaboration among industry silos with a history of passive-aggressive relationships. Not surprisingly, the recycling processes in use today have been optimized for efficient deinking of offset ink formulations.

There is of course some irony involved with the fact that aqueous inks – understood to be a “green” technology – represent an impediment to the recycling of paper. Yet there it is.

This year, as we head into drupa 2016, there is every reason to believe that de-inkability has begun to get the attention it deserves. In no small part, that is thanks to INGEDE.

Yes, there is a de-Inking trade association: the International Association of the Deinking Industry (INGEDE). Originally founded in 1989 by European paper manufacturers, one of INGEDE’s most important missions in the twenty-first century has been to drag the parties involved in inkjet de-inking issues to the table. The association’s efforts eventually resulted in the formation of Digital Print Deinking Alliance (DPDA), which is currently comprised of Canon, HP, Kodak,Oce´and Ricoh.

Human nature being what it is, the digital de-inking challenge resulted in robust discussions between inkjet printer manufacturers and the paper industry as to how serious the deinking situation was. Ultimately it came down to who was going to devote the resources to fixing the problem.

INGEGE and DPDA didn’t see eye to eye at first. When INGEDE developed the Method 11 deinking standard, DPDA pushed back with fixes that INGEDE deemed inadequate. You read between the lines in the press releases, it isn’t a stretch to conclude that sometimes the discussions were very robust.

But this is not easy.

The de-ink fix involves collaboration among powerful global players who are protecting trade secrets and are less enthusiastic about the whole de-inking thing than developing new printers. On the other side paper companies historically have a chip on their shoulders. Furthermore, any testing has by necessity to be system based: printing platform, ink formulation and paper stock.

Manufacturers who intend to play in the production speed inkjet market of the future understand they have to deal with this issue. Longer print runs probably mean larger customers, and larger customers probably mean more sensitivity to sustainability issues. Although progress toward a greener world moves by fits and starts, the global circular economy can be expected to expand as a fundamental unpinning of all commercial enterprises. It is therefore reasonable to expect the role of paper recycling to evolve as well.

After a slow start, good things began to happen in the inkjet de-inking world. In 2014, INGEDE delivered what amounted to their first de-inkability seal of approval for a web-fed aqueous system (KBA Rotajet). Likewise, London’s University of the Arts, Western Michigan University and other academic institutions are working with manufacturers on developing and evaluating de-inking technology. FOGRA began publishing an inkjet de-inking approval two years ago.

We have good reason to expect game changing production inkjet platforms to be unveiled on the drupa ’16 show floor. We will hear about leaps in production speed, solid coverage density, scalability, resolution, reliability and affordability. That is all invigorating, but if you find yourself involved in a floor demonstration and need a change of pace, try asking the sales person about the system’s de-inkability characteristics.

Let us know what they say.

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