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Digital Printing



New contenders have entered the digital printing field, with inkjet as their application of choice.



Published July 11, 2005
Related Searches: Digital printing Labelexpo Bar codes Label industry
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In the five years since digital printing became available to narrow web printers, interest in the technology has been fairly strong. Labelexpo USA 2000 was a good barometer of that interest: The Indigo and Xeikon booths teemed with attendees who expressed genuine interest in learning all they could about the equipment, the technology, the inks, the costs, and the quality of the printed products that issued from these machines.

Acquisitions of digital printing machines, however, have been made by relatively converters, possibly because prices are high, possibly because the technology is still developing. The field has been occupied by just Xeikon and Indigo — and it’s likely that converters want to see what’s coming next.

What’s next is here now, and it’s called inkjet. Converters at Labelexpo also flocked to the Chromas Technologies booth to see the Argio 75 SC, the single-color digital printing module developed by the Digital Label Alliance (DLA), a group of converters working with Chromas. Mark Andy’s exhibit space drew crowds to view the Dot.Factory, a multi-color inkjet printing unit developed by Barco Graphics, which Mark Andy plans to incorporate into a flexo press by 2001.

Xeikon’s dry pigmented polymer process and Indigo’s electro-ink digital offset process are now joined by two partnerships pushing the ever-evolving inkjet technology. The narrow web label industry has held back so far in its acceptance of fully digital printing, but the interest is most certainly moving toward enthusiasm.

The move to digital printing and the advantages it offers are being driven by two forces that converters no longer can ignore. These are short run production, and variable data and imaging. Converters’ customers are putting the pressure on them for labels and packaging that serve ever smaller and more fragmented markets, for slightly different SKUs with text, number and bar code changes, picture changes, even language changes.

This is where a digital printing machine excels — no stopping of the press, no plate changes, no makeready waste, all changes transmitted to the printer by a computer, all new images appearing on the web without a gap, without a halt in speed or quality.


The inkjet contender
Indigo’s Omnius web-fed press utilizes a unique technology wherein proprietary liquid inks are transferred to a blanket via electrical charge and imprinted upon the substrate. The Xeikon engine also employs an electrical charge to distribute the ink to a specified image area on its print drum, though the ink is dry, and is referred to as pigmented polymer.

The DLA’s Argio engine makes use of inkjet technology, not at all new or proprietary but in this case highly evolved. It can operate at a maximum speed of 100 feet per minute.

“It uses UV curable inks that are specifically designed for the Argio’s inkjet heads,” says Rob Rogers, the DLA project leader. The resolution is 600 dpi with one gray level, and the current print width is 7.6". The Argio can control the size of the ink drop that is deposited on the substrate with a variation of about 35 percent. Colors available today are red, blue, green and black, and Rogers says that Chromas can match more than 85 percent of Pantone colors.

“The inks are formulated for this print head,” he says, “and they’re difficult to manufacture.” The company is working on an ink mixing system to allow customers to mix on-site. At the moment there is no white ink for the Argio, because white contains concentrations of titanium oxide, which is heavy and tends to settle, thus inhibiting the inkjet process. “We are working on it,” Rogers notes. Metallics and fluorescents are also not available, also because of heavy particulate.

The Argio can be incorporated into any existing press. Right now it is being tested at the beta level in the production facilities of four DLA members, and units have been installed in Webtron, Comco and custom-built presses.

According to Rogers, the beta converters are producing “high quality variable data, really small bar codes such as those used for the electronics market.” These can easily replace thermal transfer labels, whose margins are high. “We run 20 times faster and use 20 times lower consumables,” Rogers says, “and with better print quality and ink adhesion.”

The biggest application so far for the Argio, he adds, is in the production of multiple SKU work, or versioning. “That type of work involves having a background that remains the same, and with one color that changes. An example could be nails that are sold in hardware stores,” he says. “There are 200 different types, with the same background on the packaging, but with a different picture and description. The Argio printers are going after large accounts and telling them that they can do the exact same work at the same price, but digitally, in any quantities, as long as the orders are bunched together — 20 labels for one type of nail, 10,000 for another.

“The cost per label is low,” he claims. “A lot of people are trying to do this type of work with an Indigo or a Xeikon, but the cost per label is high.”

Chromas and the DLA are not selling the Argio to customers outside the alliance yet, according to Patricia Santiago, marketing manager for Chromas, but they are taking letters of intent.

“The Argio’s performance has to be 100 percent to our satisfaction before we sell it,” she says. “It’s now in the final stages of beta testing.”

When it reaches the marketplace, the Argio 75 SC is expected to sell for a base price of about US$230,000, which includes the computer, touch panel, mounting frames, software, maintenance supplies and installation.

Down the road, says Santiago, is the likelihood of a fully digital press. “When, we don’t know. The DLA program first started with plans for a fully digital press,” she adds, “but the partners shifted direction. We haven’t lost that vision, just put it aside for a while.”

Los Angeles Label, one of the DLA members, has the Argio unit mounted on a Webtron press and has been one of the technology’s beta sites.

“As with any new technology, we’ve had our share of bumps and a learning curve,” says Valestrino. “But it’s a tremendous piece of equipment, and right now it’s working out very well for us. When look at the potential, and where the technology will be in a year, it’s extremely exciting.”

Los Angeles Label is using Argio’s variable imaging capability, changing multiple copies on the fly, imprinting consecutive numbers and bar codes. “One bonus is the print quality,” Valestrino adds. “It prints a heavy layer of ink, similar to the silkscreen look. You can actually feel it raised with your finger on three- or four-point type.”


SPICE rack
Barco Graphics developed the Dot.Factory using inkjet heads from Xaar, a UK-based company. The heads are mounted into a SPICE rack — Single Pass Inkjet Color Engine — under which the web travels. Each head is 70mm wide.

Mark Andy has signed an agreement with Barco to develop a multi-color inkjet unit that will fit into its Model 2200 press. Ken Daming, director of product management for Mark Andy, says the initial development will be on a 13" wide machine that can be configured along with flexo print stations in any configuration the customer desires.

“If they want to lay down a white opaque first, they can do that on a flexo station,” says Daming. “They can put a couple of flexo stations before or after the digital print station, then continue with diecutting, foil stamping, stripping, laminating, whatever our presses already do. This is just one more printing process.”

The Xaar inkjet head, he explains, has a resolution of 360 dpi, but has eight levels of gray scale. Simply stated, each nozzle shoots between zero and seven droplets, all of which combine into one dot before striking the web. That allows for eight dot variations, “and the advantage is in the resolution. We have a relatively low resolution, but with the varying size of the dots we end up with an apparent resolution of 1,080 dpi,” Daming says. “Because the resolution is at 360 dpi there aren’t as many nozzles, and less of a chance to plug up. If it was at 600 dpi the nozzles would be smaller, and you can’t get as big a pigment particle in there.”

Inks for the Mark Andy/Barco digital printer are still in development, but the goal is to produce the four process colors first, then to be followed by orange and green to allow production using the six-color Hexachrome process. Daming says the unit will operate at 70 feet per minute, “and as far as we know there are no limitations on substrates. The inkjet doesn’t touch the web so it doesn’t have fusing problems. We should be able to run substrates ranging from film to tag stock.”

Beta testing is expected to take place by summer 2001, and attendees at Labelexpo Europe next September might see the new unit in Brussels.


Inner workings
Among the comments voiced most often about fully digital presses is that they are slow. The Indigo Omnius press works at speeds up to 24 feet per minute. The Xeikon engine, which also is utilized in Nilpeter’s digital press, can print at a maximum speed of 48 feet per minute. These speeds are for complete printing of four- and five-color process jobs.

The speed is limited by the printing process. Inside the Xeikon machine, the dry pigmented polymers are fused to the substrate, using heat at 130° C (266° F). If the machine moved faster than 48 fpm the fusion would not take place.

The speed of the Indigo machine also is limited by the ability to transfer inks from the blanket to the substrate, one at a time until all are deposited on the film or paper.

Within Xeikon’s press, the computer-generated image to be printed is written on an imaging drum using LEDs, one color at a time — white, yellow, magenta, cyan, black. Thus charged, the drum passes the polymer tray where the ink is transferred.

“The LED gives the drum a charge where it wants the image,” says Don Bence, Xeikon vice president and general manager, packaging products. “The image is not controlled just by dot size, but by dot depth. The strength of the charge and its area gives the gray levels. With the Xeikon process we work with 256 gray levels — that’s what gives it the high resolution.”

The rotating drum then comes into contact with the substrate, and an opposite charge on the back of the web pulls the polymer off the drum onto the substrate. The Xeikon engine is capable of producing a continuous, non-repeating, unbroken image 12.5" wide and an impressive 30 feet long. A 19.75" width is also available.


Time savings
With a digital press, the converter abandons quite a few steps in the print production process, and proponents offer these as good reasons to consider digital printing technology. Beyond creating the digital image on the computer, there is no film output, no plate exposure and processing, no plate mounting, no conventional ink preparation, no doctor blades, anilox rolls or metering rolls, no delicate impressions to set. In short, no makeready, and no waste to go along with it.

“A lot of people out there are tired of paying set-up costs to printers. They are paying $60 per thousand for labels and $400 for set-up charges, for 25,000 labels,” says Ray Dickinson, product marketing manager for Indigo America. “With an Indigo Omnius you get a head start.”

Indigo, Dickinson reports, is planning to introduce several newer and enhanced versions of the original Omnius in the future. The Webstream 200, for example, will run at almost 100 feet per minute. “With that yield that’s more than you get off a conventional press,” he says. “And the yields are superior to those of the conventional press, which is running at 180 feet per minute but only 50 percent of the day. With the Webstream you get the yields of the conventional narrow web press but the economies of the digital, and the flexibilities.”

Indigo is at work on a Series 2 print engine, which will be twice as fast as the one available today. “That’s about two years away,” Dickinson notes. Indigo will achieve its increased speeds by adding print engines onto presses. For example, two engines operating at 48 feet per minute each will have a total output of 96 feet per minute.


Finishing up
Indigo and Xeikon digital presses are stand-alone printing machines, and do not come with the variety of finishing equipment that is customary on an analog press. Many companies who supply finishing equipment are hard at work to capture the attention of digital converters, proposing solutions for postpress.

“The problem with short run work is how to deal with the finishing part of it,” says John Little, president of Nilpeter USA, the North American arm of the Danish press manufacturer. “If you take it off of the digital press and run it off-line, you have one person running a digital machine and another running off-line. If you use the same person, it will take twice as long.”

For this reason, Nilpeter has developed an in-line finishing system that goes onto the end of the press. It utilizes a magnetic diecutting plate cylinder that is adjustable to the size of the label, and after cutting one image it spins around to cut the next one in the row. The system comes with an accumulator, which stores printed labels from a second job while the die plate from the first job is being changed.

Little sees gradual growth for digital printing, and a lot more interest this year than in the past. “I don’t think that digital will replace current printing methods in the next few years,” he says, “but there will be an increase in the number of digital units. It will make inroads in different areas and will become more competitive in short run work. You really have to build a market for it.”

“At this stage it’s not perfect for everything, but in a year or two I can see it very well taking over all one- to three-color label runs under 100,000 quantity,” says Nick Valestrino. “When you find the right fit for it, the customer says: ‘Where have you been all my life? I’ve been waiting for someone to offer this to me’.”



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