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Inkjet will be out in force at Drupa 2008, but its presence will be nuanced. Expect to see and hear about some applications that are ready for the market almost immediately and others where the suppliers are preparing products that may not see the light of day until subsequent shows.

“Drupa 2008 will be the inkjet Drupa, but not as big as the 2012 inkjet Drupa,” says Xaar chief executive Ian Dinwoodie.

No one doubts that the halls of the Messe Düsseldorf in May and June will be full of inkjet machines, but it’s becoming clear that unless there is something totally disruptive that is still under wraps, it’s unlikely there will be an inkjet press that directly challenges the workhorse sheetfed litho machines as a viable option to buy from next June.

Inkjet will be continuing its march to higher speeds, higher quality, better reliability and more value for money. Evidence that it is moving in the right direction is that in addition to the latest wide-format beasts exemplified by the Agfa/Thieme M-Press and the Inca Onset, which use massive arrays of heads and multiple passes to build up an image, there will also be a plethora of single-pass narrow web inkjet machines. Some of which will be for the label market and others offering high speed for the transactional and transpromo markets.

“In terms of inkjet, Drupa will be about single-pass,” says Dinwoodie. That’s possible because of the efforts that have gone into increasing the reliability and robustness of the printheads, as in single-pass applications a blocked nozzle destroys print quality with a white line running through the print. Xaar is pushing its Xaar 1001 head, which uses Hybrid Side Shooter (HSS) technology to reduce nozzle clogging by constantly circulating the ink behind the nozzles. While inkjet has sometimes been a temperamental technology with clogged nozzles and lots of downtime for cleaning and maintenance, Dinwoodie claims the latest generation of heads will need to “brush its hair and widen its nose type maintenance” once every eight-hour shift.

A taste of things to come was revealed at Label Expo last autumn when The FFEI Caslon single-pass inkjet module using Xaar heads on a Nilpeter press was shown. Running at 25m per minute, it is typical of the label print applications being developed. Dinwoodie says: “We’re getting end users talking about image quality that is better than flexo.”

Packaging challenge
It’s a common refrain and is echoed by Inca Digital managing director Bill Baxter. He says that a picture is starting to emerge about how inkjet is developing. First, with wide-format it took on screen process printing and the display market, now single-pass technology is taking on flexo in the labels market, and in time, as experience and confidence builds, the webs will get wider and flexo will make way for inkjet in the flexible packaging and corrugated board print markets. “The applications everyone lusts after are in packaging,” says Baxter. “One day, it will be possible with inkjet, but I’m not sure that’s just yet.”

He believes that cracking commercial print with inkjet is a more difficult challenge describing it as “a nice long-term challenge”.

“Offset is very good, the quality is excellent and the price is cheap,” he says. That’s not to say he dismisses inkjet out of hand in the commercial market, just not yet and not totally replacing litho. “I can see people printing with inkjet onto B1 sheets, but it won’t compete with offset, it will sit alongside,” he says.

Radical technologies
Drupa will also herald demonstrations, announcements and discussions about strategic partnerships for next-generation products and technologies that will provide some pointers to what market sectors inkjet will tackle next. Two of the next generation technologies making their presence felt are Kodak’s Stream and Cambridge start-up firm Inkski’s eponymous printhead project. Stream is much further along the road to commercialisation than Inkski and will be shown as a prototype machine with pledges of shipping within 18 months of the show. Both technologies are aiming to eventually match the speed, quality and cost of offset litho including what are currently high-speed wide-web applications such as newspapers and magazines. To reach that level or performance, they use radically different technologies to today’s dominant inkjet technology piezo.

Of the new inkjet technologies, Kodak’s Stream is the one tipped by most commentators as the most promising both in the short and long term, while Inkski is the most forthcoming on its technology.

“If they can make it work, it changes everything,” says Inca’s Baxter of the Stream technology. Both use fundamentally different approaches to the current crop of printheads and to each other. What is common to both is that they are aiming for much higher linear speeds with a single head than current inkjet machines achieve by using arrays of multiple printheads. At Drupa, Kodak will be showing a 2.5m per second (500ft/minute) machine, and has previously suggested the technology can go much faster. Inkski claims its heads will be able to work at 10-20m per second. “That takes digital technology to more of the speed of today’s fastest presses – the world’s fastest newspaper presses run at 16m per second – suddenly you can digitise that,” says Inkski’s director of business development Bryan Palphreyman.

Palphreyman says the firm has proved its concept and is a year from a prototype printhead and four to five years from a press. Others in the industry are more circumspect and believe that based on the time it took to commercialise piezo inkjet, it’ll be nearer a decade before a machine is running. Inkski won’t be exhibiting anything at Drupa but Palphreyman says he’d be very surprised if the firm or one of its partners didn’t make an announcement at the show.

Inca’s Baxter doesn’t think it’s time to write off piezo drop-on-demand technology just yet. “It may be that piezo gets super­seded by these glamorous new technologies, but it may not.”

For all the talk of new printhead technologies offering speeds up to 10 times faster than the best of today’s offerings, Baxter points out just how far inkjet has come in the past few years without the need for radical re-invention.

“Since we launched the first (and then fastest) flatbed, the Eagle 44 in April 2001, throughput has gone up by a factor of 25 when compared to our latest machine the Onset,” he says. “In those terms, inkjet developments have exceeded Moore’s Law.” Named after Intel co-founder Gordon Moore, Moore’s Law states the computing power of semiconductors doubles every 18 months. Baxter continues that if you measure value for money (performance/price), inkjet is 10 times better.

“I don’t think the print industry can sustain that level of improvement for the next six years, but we’re still talking of improvements as multiples and not percentages,” he adds.

Underlying that, printhead speeds have at best doubled, with the improvements coming from knitting multiple heads together as well as from improvements in the overall system. Current inkjet technology is about to move beyond the speed argument to a much more important one for everyday use – that of robustness, trouble-free operation and the flexibility to print onto many different substrates.

For day-to day-operation, Baxter believes the areas to look at aren’t the printheads at all. “Quiet improvements in ink will be more important than load printhead developments,” he concludes.

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HOW IT WORKS: INKSKI LIGHT INITIATED LIQUID OFFSET









Inkski’s concept uses a process called Light Initiated Liquid Offset (LILO), which is a radically different method of forming droplets of ink and then steering them onto the substrate. Director of business development Bryan Palphreyman argues that it’s not really inkjet but rather a relative of inkjet. The most striking thing is that there are no nozzles and chambers to get blocked, which opens the design up to work with a wide range of inks.

The second thing is the technology is designed to ultimately be as fast as today’s offset and gravure webs running at 10-20m per second using a single head rather than multiple heads LILO can be thought of as a hybrid of two old print technologies, the expose unit of a drum scanner and an anilox cylinder. A stream of ink is directed onto the outer surface of a spinning glass cylinder. On the surface of the cylinder are what Inkski terms surface features, on which ink drops form, akin to the cells on an anilox cylinder. The pattern on the cylinder determines the resolution and spot size produced and inside is a linear array of infra red diodes, similar to the exposure systems of the toner-based digital presses and thermal platesetters. To fire an ink drop, an infra red diode is fired at the cylinder as the dot to be printed passes under it. The small dose of energy from the diode is enough to kick the drop from the cylinder, where surface tension has balanced the centrifugal force, onto the page. It is the use of the light as a switch and not a pump that gives the potential for such high speeds.