Ink-jet: A Disruptive Technology

THERE HAVE been significant developments that make ink-jet a more viable process and now thrust it into the mainstream of the printing industry.

The ink-jet market is growing in every direction, from flatbed and wide-format, to label, to transpromo, to commercial web and sheet. Print head manufacturers are accelerating their developments, and new inks are being introduced almost daily.

Today’s ink-jet technologies are undergoing a number of significant quality and performance evolutions. These changes will combine with advances in new jettable fluids and inks, with improved materials handling and substrates—all of which are leading to a new generation of cost-effective printing solutions. But many of these solutions are due in the 2009–2011 time frame.

Present and future systems will have a major impact on how printed products will be created, printed, distributed and managed, and ink-jet could truly be a disruptive technology. In the coming years, we will see printing systems employing ink-jet technologies replacing some of the dominant printing tools, workflows and supply chain practices being used today.

Of all printing processes, only the ink-jet process does not come in contact with the materials being printed, making it both substrate- and application-independent.

Ink-jet also uniquely integrates easily into multi-step manufacturing processes, because it can be inserted at various points in the production line to decorate or pattern materials as they are formed.

A Challenge to Toner

Full-color ink-jet printer/presses challenge toner for many—if not all—applications and open up the potential of medium- to high-volume offset litho markets previously closed to digital production. Hybrid combinations of ink-jet and offset—as well as ink-jet and flexo for packaging applications—provide another dimension to the way in which processes are used to cost-effectively produce differentiated products.

Offset vs. digital quality is no longer an issue. Offset has benefits in running speeds and sheet size that generate many more finishing options. Many digital presses, however, have a significant benefit in offering in-line finishing and printing of a complete product that may make use of many different substrates in just one pass.

The cost of offset litho print has fallen by nearly 50 percent over the past decade, partly as a result of productivity improvements. But it still cannot compete with the very short runs of digital printing, or the variability which digital printing provides.

Ink-jet technologies will produce even faster speeds and higher levels of quality at lower cost per page in the coming years. One needs only to plot the changes that have already occurred to see the trend. The applications that were open to the early ink-jet technologies were limited by their quality and cost, but that is changing. New approaches expand the role of ink-jet for transactional printing and direct mail. It lowers the barriers for entry into the growing transpromo market. It will also bring ink-jet into applications that were typically only feasible with offset or flexo or screen printing, such as publications (newspapers and magazines), catalogs and newspaper inserts. These developments will even increase the range of commercial printing applications that may transfer from conventional processes.

The Clogging Conundrum

Idle piezo heads are problematic and can lead to blockages caused by changing properties of the ink in the nozzle area. Steve Hoover, vice president of the Xerox Research Center in Webster, N.Y., described what he refers to as the “ink-jet paradox”: in order to successfully jet current inks, manufacturers need to use print heads with very fine nozzles, which are subject to clogging by the thicker inks used by flexo or offset technologies. However, watery inks have their own problems, often related to drying of ink on untreated substrates.

Hoover claims Xerox has a better solution, which it has been using for many years—namely, its solid-ink technology. Once heated, these inks are readily jetted onto the media, rapidly cooling to adhere to the substrate and providing good quality results. Hoover added that for commercial and industrial applications, Xerox has taken its solid ink technology to the next stage of its development by turning the ink into a gel.

Kodak has a number of new ink developments and intellectual property. STREAM inks can have pigment particles ranging from 10 to 60 nanometers in size. These micro particles cause less damage to silicon nozzles and clogging should be a non-issue.

HP, Kodak and many other companies have page-wide array technology in their R&D centers. Some developers say that page-wide systems do not work as consumer products because the nozzles, which don’t move, can’t be cleaned. Some industrial-strength systems continually re-circulate ink through the print heads, even when the system is not printing.

The HP Inkjet Web Press has a sophisticated system to check for clogged nozzles and circumvent them as well as making their print heads completely replaceable after some period of time—perhaps as often as every shift—depending in print volume.

Summary

The pace of development in ink-jet printing is accelerating. The number of models for every application is increasing and functionality is growing. Just as toner-based printing has usurped some offset litho volume, ink-jet will usurp some offset litho as well as some toner volume. There are new dynamics in the printing world, and we must be attuned to how they will change our businesses.

This article is an excerpt from the new book “Ink-jet! History, Technology, Markets, and Applications—Volume 2,” which was commissioned by PIA/GATF’s Digital Printing Council. It contains a very thorough look at the ink-jet technologies unveiled at Drupa and is available from PIA/GATF Press at: www.gain.net.

Frank Romano’s career has spanned more than 40 years in the printing and publishing industries. He is the editor of the “International Paper Pocket Pal” and has written hundreds of articles for publications around the world. The author of 45 books, he has also founded eight publications. He lectures extensively and has consulted for major corporations, publishers and government agencies. He was the principal researcher on the landmark EDSF study “Printing in the Age of the Web and Beyond.” Romano continues to teach courses at RIT and other universities. You can e-mail him at fxrppr@rit.edu.