But now, after two decades, several other manufacturers are coming out with liquid toner digital presses of their own. The attraction is that liquid toner presses can potentially print much faster than dry toner. And, unlike high-speed inkjets, they can print onto standard offset stocks without expensive pre-coatings.
The two liquid toner newcomers closest to market are Canon, with a large-format packaging press, and Xeikon, with a medium-format document press. Miyakoshi and Ryobi have a sheetfed B2 press in Japan, but there’s no UK release scheduled just yet. Last year Heidelberg announced it had a liquid toner project, but hasn’t revealed any details.
HP Indigo, with its head start, is currently on its third major generation of narrow-format (so SRA3 sheets and web equivalents) presses and is now installing the first commercial sheetfed models in its forthcoming wide-format range (for B2 sheets and web equivalents).
Benny Landa, the founder of Indigo, says: "Many people think we invented liquid electrophotography. We didn’t. It was invented in 1952 by a man named Ken Metcalf in Adelaide, Australia. We just made it work. We did not invent the idea of injecting an ink onto an intermediary and transferring it onto paper either. All I did at Indigo was to take offset print and marry it to electrophotography, which nobody had done before."
Familiar characteristics
Simon Lewis, director of strategic marketing at HP Indigo, explains the reasons liquid electrophotography (LEP) works from his viewpoint. "LEP is so powerful because it allows a print look and feel that in many of its characteristics is similar to many of the processes that have been predominant for a long time. It allows a thin film of ink that takes on the structure of the substrate and doesn’t have a particular gloss level of its own. You can use that process to print on an almost endless range of substrates, whether it’s paper or plastic, coated or uncoated, textured or smooth. That means you have the ability to address a very diverse range of applications and needs."
Given these benefits, it seems pretty clear why more manufacturers are now following suit. The bigger mystery is why only now.
Lewis admits that "all of these benefits come at a cost". He explains: "The complexity of the Indigo printing process is pretty high. Our system is relatively more complex than a conventional press – there is more to learn and more to maintain."
What has changed, he explains, is that vendors now have a larger incentive to overcome this. "What’s happened is an understanding from the different vendors out there in the market that dry toner has got as far as it can," he says. "If you’re going to smaller and smaller toner sizes, unless you encapsulate them in a liquid, then the toner is getting uncontrollable."
The first of these newcomers to reach printing sites will be the Océ InfiniStream liquid toner press from Canon. It is currently installing the first pair at its demo centre on the outskirts of Munich and at a nearby but unidentified beta site. The nominally B1-format simplex press is roll-fed and aimed at the folding carton market. It runs at 120m/min, equivalent to 14,400 B2 sheets or 7,200 B1 sheets per hour. It can print on standard offset carton board up to 600 microns thick.
Running costs have yet to be worked out, says Roland Stasiczek, director of marketing for InfiniStream technology, though the predicted economic crossover point between InfiniStream and offset will be 3,000 to 4,000 B1 sheets. The oil-based ink is currently going through food certification tests, he says.
The first two installations will be CMYK initially, but will be converted to seven units early next year. Standard configurations will include an inline dryer, inline coater and a sheeter.
The InfiniStream is in fact an example of other vendors besides HP not being as late to get involved as it at first seems. Instead liquid toner has been under development for several vendors for some time, with the hoped for result being enhanced sophistication.
Stasiczek says that liquid toner development for InfiniStream in fact started 10 years ago. "Our goal was always to increase the productivity of our system," he says. "Indigo was first to the market, but it’s not so productive. It’s quality oriented. Ours is an electrophotographic process that uses a new liquid toner, that’s low viscosity compared to Xeikon’s high viscosity. The major components are the same as for our black and white VarioStreams. The biggest change is a rubber blanket cylinder to transfer colour to the paper.
"It is in some ways similar to the HP Indigo process. The big difference is that we do not build up multiple colours on the blanket and we do not pre-charge the toner. We have one unit per colour, where Indigo builds up colours on the same unit. This is one of the major reasons why we achieve higher speeds. HP ink is a polymer on the blanket and by then the toner is electrostatically ‘dead.’ Ours is electrostatically alive on the blanket."
A consequence of this is that the ink remains liquid on the substrate and the press is fitted with a substantial hot air/infrared drier at the end to evaporate the volatile oil.
Then there is Xeikon, which showed its Trillium process as a very early single-unit black-only prototype at Drupa 2012. Xeikon says the first four-colour duplex presses will be ready for distribution by spring 2014. Initial speed will be 60m/min, although Xeikon is confident this can be increased over time, having seen double this in its labs.
Xeikon will manufacture the presses and toners in its existing factories in Belgium, but the core technology was bought in when the company acquired the rights to a patent that it is constrained from discussing, but which appears to have been acquired from Research Laboratories of Australia.
Trillium is roll-fed with 500mm print widths, using a different liquid ink process to Indigo or InfiniStream and particularly small 2 micron toner particles. "The major difference with HP Indigo is that we do not pre-charge the pigment particles," explains Danny Mertens, business development manager for document printing. "So we ship uncharged liquids, which have a longer shelf life. The second big difference is in the fusing. Indigo does transfusion, ie image transfer and fusing on the same drum. This wears out the blanket.
"We do not have a hot blanket and we fuse afterwards. We do not have to evaporate the oil to remove it. It is removed mechanically."
"The HP Indigo process runs at one or two metres per second for single colours, but slows down when it builds up multiple colours on the same unit. Ours is one or two metres per second too, but we don’t slow down because we use multiple units."
Other developments
There is less information forthcoming on other liquid toner presses known to be under development. At last year’s Drupa Miyakoshi announced a joint venture with Ryobi on a B2-format sheetfed press,
combining a Ryobi 750 chassis with Miyakoshi liquid toner units, plus a fuser-drier unit at the end. A four-unit prototype was running at Drupa at up to 8,000 sheets per hour.
Apex Digital Graphics managing director Bob Usher says that the press has now been launched in Japan with a few beta installations, but he’s not currently planning to bring it to the UK. "They had an open day at Miyakoshi six months ago and showed it there, but the B2 market was depressed and we decided the time wasn’t right to bring it here," he said. "Also the exchange rate doesn’t help." He estimates that a press would cost around £1.5m.
Heidelberg mentioned a liquid toner project at a press conference last year, but subsequently clammed up. Jason Oliver, senior vice-president of digital print solutions, said the firm would continue its "silent approach to the market" about the project, but added that it would have some news about that project and its broader digital strategy in the "near future".
So just what this new wave of liquid toner presses will consist of remains, in some instances, to be seen. It’s evident that liquid toner is not seen by its developers as a replacement for established digital technologies. But liquid toner evidently has more speed potential to come. So if it really can match offset speeds and costs per copy, on standard papers, maybe the future won’t belong to inkjet after all.
Landa leaves LEP behind
Although Benny Landa was the first to make a commercially successful liquid toner digital press at Indigo, he’s abandoned the process at his second company, Landa Corporation.
Landa’s Nanographic presses, previewed with great pizzazz at Drupa 2012, use an offset inkjet process. The NanoInk comprises 10 nanometre resin-pigment particles suspended in water. This is jetted onto a heated offset belt, where the water evaporates to leave a very thin adhesive pigment image that is then transferred in contact with the substrate.
Landa argues that this has higher speed and quality potential than LEP, together with running costs that match offset. "I know liquid toner as well as anyone, I’m very familiar with it," he says. "Suffice it to say that in tomorrow’s world, if you are not water-based, you are not going to be able to be in the business, in my opinion."
