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Inkjet points the way as the printing technology of the future

Issue #1008/1 – IPEX 2010 at the NEC exhibition centre in Birmingham, UK, was the scene for the first showing of several new high-speed continuous feed web production print units – utilising inkjet technology – and pointing the way towards the future of production printing. Could this development ultimately influence the office printing market?

In a number of previous issues of TCPglobal, we’ve talked of the ‘Holy Grail’ factor in office printing – laser technology. This factor has also applied to production printing with production presses migrating from analogue offset lithographic technology to digital electro photographic technology.

Bizarrely, the inks used for offset lithographic printing are essentially liquids, albeit with a very high viscosity. So, the production printing industry seems to be coming full circle back to ink again, having flirted with toner for a number of years.

Ink technology, as opposed to toner-based technology, has some major advantages in terms of environmental impact – while toner technology has really proved itself to be very unfriendly to the environment, causing very high levels of waste that, at best, require detailed and expensive recycling and, at worst, contribute to unacceptably high levels of landfill.

Three high-visibility manufacturers were showing ink-based production printers at IPEX – Xerox, Hewlett-Packard and Kodak, each with their own twist on the technology.

For Xerox, the inkjet production press is a heavily up-scaled version of the engine that features in its ColorQube office MFP. By ‘heavily up-scaled’, I mean to the extent of incorporating 56 print heads similar to those used in ColorQube (which uses 4 print heads!). Xerox has an impressive bank of experience on which they have been able to build this machine, having been involved in solid ink printing for more than 20 years (including the days of Tektronix) and having built more than a million of these print heads.

Xerox Inkjet Production PressXerox Inkjet Production Press

Whereas each print head in ColorQube carries four sets of nozzles (Cyan, Magenta, Yellow and Black), and replicates the heads across the paper path to create the width of print swath required to print an A3 page, the production press has single colour print heads that are not only stitched together to provide the 20.5 inch print swath but also duplicated to provide the four ink colours required and then also to provide the density of ink droplets (600dpi) needed for single-pass printing.

Because the inks are polymer resin, they are solid when at room temperature but fluid once heated. Rapid cooling as the ink is applied to the paper means that the machine is capable of printing on almost any paper, thick or thin, not requiring any special treatment or coating and without soaking into the paper (causing the somewhat unsightly show-through that is typical of liquid inks). This also means that thinner media can be used, thus saving money and trees.

Xerox’s solid ink formulation also fits the bill environmentally in other areas:
– With an increasing emphasis on de-inking as part of the paper recycling process, solid ink enables de-inking much more easily than other ink formulations and without requiring bleaching
– Solid blocks of non-toxic ink require minimal packaging and …
– Because small blocks have a high page yield, transportation costs are also minimised.

Kodak Prosper PressKodak Prosper Press

Kodak has also introduced an inkjet production press, Prosper Press, again utilising a new and proprietary technology development called ‘Stream’. As a concept and printing technology, continuous flow inkjet is not new but Kodak has developed a technique for controlling the stream of ink more accurately to provide high quality hard copy output.

Ink flows under pressure through the nozzles but heat pulses at the nozzle warms the surface of the ink to change the surface tension characteristics of the ink stream. The result is that the stream breaks into droplets according to the heat pulses applied.

But, only a portion of the ink expelled from the nozzles is used for printing and yet the flow of ink is continuous. Therefore, the unwanted ink has to be collected and recycled back into the ink supply without it reaching the paper. The heat pulses at each nozzle break the ink into large droplets for printing and small droplets that are diverted for recirculation. The time between pulses and the flow of ink, both of which are easily controlled, determine the size of droplet produced.

Kodak claims that the benefits of its Stream technology is high quality printing on a wide variety of materials, including glossy, at a very low cost.

Hewlett-Packard T200 ‘Baby’ Web PressHewlett-Packard T200 ‘Baby’ Web Press

Hewlett-Packard’s new offering is the T200 ‘Baby’ Web Press, which follows the launch of the T300 at Drupa. It is a more traditional inkjet technology but with the advantage of printing duplex from a single engine without turning bars and allowing accurate back to front registration. It also sits on a small footprint.

Unlike Xerox’s solid ink technology, Hewlett-Packard’s Web Press uses a clear Bonding Agent that is applied to the areas where an image is to be printed. This helps prevent the liquid ink from soaking into the paper too much and allows printing on a wide range of standard papers.

Taking this technology a step further, Hewlett-Packard has developed ColorPro technology – a commercial printing variation on the ColorLok technology used for cut sheet office inkjet plain papers. ColorPro treated paper again prevents the ink soaking into the media too much, increasing gamut and optical density and holding the ink tightly in place for crisp lines and text.

At this end of the market, production presses are continuous feed devices, with paper cutting being handled after printing.

Kodak’s Prosper Press, with its Stream technology, is the fastest of these three devices at 650 feet per minute print speed. Xerox’s solid inkjet production press follows fairly closely, capable of running at 500 feet per minute. Hewlett-Packard’s new Web Press appears to be the slowest device, representing the entry level for inkjet web production printing, with a print speed of only 200 feet per minute in colour – but capable of 400 feet per minute in mono. However, these print speeds are for duplex printing!

Clearly the moral of this story is that inkjet technology is really coming of age, with development taking the technology to new heights. Essentially, if the industry can convince professional production printers to adopt inkjet technology because the quality is as good as offset litho and printing costs are reduced, then it is because it has a bright future.

We have seen the high-end A3 ‘Edgeline’ inkjet MFPs from Hewlett-Packard and Xerox’s A3 solid ink ColorQube MFP hitting the office market in the last few years. Although Edgeline appears not to have had a great impact, ColorQube is said to be very popular – and, with the ability to reduce waste materials by 90% or more, so it should!

Office hard copy buyers are more likely to be a difficult group to convince of the value of inkjet over laser for high-end office applications and there are certainly still some technological and perceptual barriers to overcome in order to produce and sell fast, high quality and cost-effective liquid inkjet devices for the office – not least of which is the need to dry the ink fast enough for high-speed printing. It is here that Xerox’s solid ink technology currently has the edge.

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