But while there are many wonderful things to be said about xerography, it has some specific limitations. Perhaps chief among these is the associated toner fusion process. To get toner to bond to paper, traditionally it’s been necessary to run the sheet or web through a set of fusing rollers that apply high levels of heat and pressure. This poses problems for any heat-sensitive substrates – plastics, some types of film and papers with special coatings all turn into sticky messes that bring the machine to a grinding halt – and that has limited the applications for heat-fused technologies.

Fusion in a flash
Xerox, chafing against these limitations, has come up with a rethink of its toner fusion process. Known as “flash fusion”, the process involves a bank of infrared lamps that act in conjunction with a new Xerox small-particle toner, containing a catalyst that cures on exposure to the IR light. There’s no contact and therefore no pressure, which, coupled with the low levels of heat involved, makes the flash fusion process ideal for printing onto a variety of substrates. And when it comes to printing onto paper, the flash fusion process also makes for a printed sheet in better condition – because the moisture isn’t taken out of the substrate, it shrinks less, has less tendency to corrugate or curl, and isn’t as brittle.

The new DocuPrint 495 CF – a continuous-feed monochrome digital press – is Xerox’s first continuous-feed digital press to use the flash fusion principle. At present, all five machines in the Xerox CF series use a Hitachi engine, requiring heat and pressure to fuse, but Xerox has such confidence in the flash fusion principle that it intends to relaunch all its CF machines to use the technology by 2010. “It opens up a lot of markets for us because of the vast variety of substrates it can print onto,” points out UK monochrome marketing manager Paul Stead. “We wouldn’t previously have thought of packaging or labels as our market, but now we can go there with the new flash fusing technology.”

Compared to other xerographic-process machines in the continuous-feed sector, the flash fusion process gives Xerox an unarguable advantage in its variety of substrates. Of the rival digital presses in this area, only Océ uses a xerographic principle, and its presses still incorporate the classic heat-pressure fusion method, which rules out anything but paper as a substrate. Of the other rivals, the Nipson VaryPress could be considered the most direct challenger. This press uses magnetography, which incorporates a flash fusion process very similar to Xerox’s, and as a result the VaryPress can print on films, label stocks and plastics easily.

Double deckers
In the CF range, the DocuPrint 495 is considered an entry-level machine, producing 472 duplex pages per minute. It’s a dual-engined press, and Xerox has saved space by stacking one engine on top of the other, making for a duplex printer just 4m in length rather than the 8m that other Xerox duplex CF presses have (and it doesn’t slow down when duplexing, unlike several other monochrome digital presses). The double-decker design also makes for less paper waste, as the duplexing path is shorter – the web travels “about a foot” between the two double-deckered engines, rather than the whole length of the press. Longer versions of the DP 495 are available, though, and Xerox can also produce a multi-engine configuration with three rather than two engines in the same line, as a breakdown back-up.

Unwinds, rewinds and post-press processing units for Xerox’s CF range are sourced from third parties, either at the customer’s choice or at Xerox’s recommendation. The firm works with Hunkeler, Stralfors Lasermax and PSE Orion, among others, via the Xerox XACT (Xerox Advantage through Certified Third-parties) programme, which means Xerox vets the kit and its compatibility. The web can exit to a number of processes, including sheeting, slitting, rewinding, folding, bookletmaking, re-fanfolding or stitching.

At present, the DP 495 is a pinfed machine, which means that substrates must be sprocketed before being fed. Xerox sells the sprocketing units, which can be put inline with the unwind to punch immediately before entry to the print engine. There are plans to offer a choice of pinfed or pinless for the monochrome CF engines in the near future, but Paul Stead can’t say whether customers buying a DP 495 now will be able to retrofit a pinless infeed.

At the front-end, the DP 495 is simple: a Windows-based Xerox controller running native IPDS (the standard page description language for mixed-content pages) with other emulated page description languages. Makeready is minimal. The controller touchscreen is used to tell the print engine what pre- and post-print devices are attached, via an icon-based drag-and-drop interface (“like doing a jigsaw” is how Stead describes it). Paper widths and thicknesses, as well as reel length, are programmed into the controller.

Multitalented machine
The DocuPrint 495 will produce resolutions unusually high for a continuous-feed printer. At 240dpi or 600dpi, it’s more than up to the job of printing for publications (ie reasonable halftones) and transactional print. In fact, the first UK installation is a book and journal printer – RPM Print & Design in Chichester – which mirrors other European take-up, particularly in Spain where the book print-on-demand market is thriving. Stead readily admits that demand from the publishing sector caught Xerox on the hop. “We’d anticipated some publishing applications for this machine, but we thought we’d tackle the new packaging markets first and let publishers come in later,” says Stead. “But I guess this is a multitalented machine with lots of possibilities, and maybe we need to let customers tell us what they want to use it for.” That the DP 495 will also handle stocks outside its published “safe” range of 64-157gsm is also exciting for publishing users, Stead says. “We have print samples from customers who are already running 50gsm paper on this machine without any trouble at all.”

One of the most exciting possibilities for the flash fusion DocuPrint series, according to Stead, is in printing labels, packaging or documents with RFID tags or transceivers embedded in them. RFID, the remote tracking technology sweeping the logistics industry, will become a big sector for Xerox. At the Hunkeler open house in Lucerne next February, Xerox will show the DP495 printing RFID tags. “The potential for fast-printed RFID labels for pallets, or packages in transport services is immense,” says Stead. “The possibilities are limited only by the user’s imagination.”

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SPECIFICATIONS
Max web width 457.2mm
Stock thickness 64–157gsm
Max speed 472ppm
Price £350,000
Contact Xerox UK 01895 251133 www.xerox.com

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THE ALTERNATIVES
Delphax CR 900
Delphax CR 900 is a single-pass duplexer that delivers 600dpi at top whack. The web can be pinfed or take standard, unsprocketed stock, but it can only be rewound at the delivery end. However, the engines use electron beam imaging technology, which requires pressure and heat to fuse, so it’s aimed purely at printing onto paper.
Max web width 463mm
Stock thickness 40–226gsm
Max speed 847ppm
Price £430,000
Contact Delphax Technologies 01293 551051 www.delphax.com

Nipson VaryPress 200
Nipson’s VaryPress range has a maximum 600dpi resolution. The web can be pinfed or pinless on a job-by-job basis. The stock weight range is comparable to the 495, but there is also an extended range available. It uses magnetography, which incorporates a flash fusing process, so the press can print on a range of stocks.
Max web width 469mm
Stock thickness 48–160gsm (40 – 250gsm optional)
Max speed 1,200ppm
Price £200,000
Contact Nipson UK 01322 295970 www.nipson.com

Océ VarioStream 7550
Océ’s VarioStream is the only other laser-based technology in the same class as the DocuPrint. Duplexing is an optional extra, but Océ can, like Xerox, put a third engine into the chassis to cover breakdowns. Infeed is pinless only. Fusing is a standard heat and pressure process.
Max web width 463mm
Stock thickness 50–160gsm pinless, 70–160gsm pinfeed
Max speed 500ppm
Price from £215,000 (single engine only)
Contact Océ UK 0870 600 5544 www.oce.com