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Demand for coating in digital print was high at Drupa and so was the response, finds Karen Charlesworth.

The massive growth in coating that has taken place over the past decade has arisen mainly from the offset sector. As turnround times have dropped and drying time has become a luxury, the practice of sealing – adding a light clear coat via a final on-press unit or a dedicated coater to boost ink absorption, speed drying and help prevent scuffing as the sheet is turned or sent on to post-press – has become much more widespread. The overwhelming majority of sealing is carried out on-press in the same pass as the printing. Some estimates now put the number of inline coaters on sheetfed presses sold in the UK as high as eight out of 10.

Inline coating has all but made obsolete its offline cousin because the extra unit on-press costs just a fraction of the investment necessary in an offline machine, while the extra handling and floorspace of offline working is completely eliminated. And as coating has become easier, faster and cheaper as a result, it has, in turn, prompted the growth of what could be called ‘non-functional’ coating: decorative finishes, spot varnishing, textured or coloured coatings and heavier-weight varnishes.

That’s offset, anyway. But how do you carry out coating if you’re not an offset printer? For the past four or five years, the question has been troubling digital printers in particular. They have been experiencing a massive surge in demand for variable data printing – particularly in mailing work, where sealing would be an ideal solution to the problem of scuffing as toner-printed mailers go through finishing lines and automated postal sorting systems. It’s clear, if the pun can be pardoned, that there is a huge demand for a practical coating solution that can be used by digital printers.

Suppliers to the digital print sector have pondered the question en masse and Drupa 2008 was a veritable showcase of responses. Broadly, the devices launched at the show divide into three types: offline roller-coaters for flood-coating work; offline UV inkjet coaters for flood-coating or spot varnishing with variable data capabilities; and inline coating units on the digital press, akin to the inline coating unit on an offset press.

Taking the last first, inline coating units, as seen on some of the industry’s flagship colour digital presses, divide between simple roller-coaters for all-over flood coating on every sheet and anilox-based systems that make it easier to coat to different thicknesses, and even to spot varnish, with a suitably-engraved anilox.

Then there are the presses with an extra unit dedicated to printing a clear toner: Canon’s ImagePress C1+ is one of these, a light production press whose popularity at Drupa, as product manager Graham Kennedy says, caught Canon by surprise. "We had no idea there was such a thirst out there for adding value to the digitally printed page in this way". In its fifth unit, the ImagePress C1+ uses a single non-pigmented toner that produces a variety of effects from matt to gloss and even metallic effects using a pre-printed halftone.

Kodak has taken a slightly different tack with an inline unit that doesn’t print the coating, but instead scrubs it up. The NexGlosser, introduced at Drupa 2004, is a kind of scouring device that polishes a fifth, clear toner to various levels of gloss. This Drupa, Kodak augmented the NexGlosser’s capabilities with the launch of a ‘dimensional ink’ – another toner able to produce textured effects.

Inline coating, however, can have some drawbacks. One is the capital cost – somewhere between £25,000 and £65,000 – while another is the fact that some inline coaters slow the press down. Then, with an anilox-based system, to apply different weights of coating it’s necessary to change the anilox itself for a roller engraved with the appropriate density of cells. And all the standard arguments of inline versus offline apply, too: what about those jobs that you don’t want to coat, and what about those jobs you print on another press that you do want to coat?

Offline dominates
Small wonder that the vast majority of new coating launches at Drupa were offline machines. Xerox, for instance, teamed up with French manufacturer MGI to strike a deal for MGI’s UV-Varnish roller-coater, to be used in offline/nearline configurations with Xerox’s high-capacity colour digital presses. Duplo entered the fray with its own-badged Ultra 205A UV Coater made by a Taiwanese manufacturer. The Ultra 205A is aimed at smaller commercial digital printers and this is evident in its automated makeready, which measures the sheet length and uses this to set up the entire machine, so as product specialist Terry Wafer says, "you could just do one sheet if you wanted to".

The Ultra 205A is unusual in that it uses three different UV-cured fluids to achieve its matt, satin and gloss finishes and a change between fluids necessitates a cleandown routine, which is semi-automated.

Another offline coater came from Morgana, via its partnership with US firm C&J Inc. The DigiCoater is a two-roller flood-coater that can also be used to apply a pre-print primer to uncoated papers. Unlike the Duplo coater, which calls for liquids to be swapped if the job requires a different finish, the DigiCoater allows both matt and gloss to be held online at the same time. Alternatively, it can produce a choice of textured finishes via different fluids.

HP chose to hedge its bets at the show with the launch of the Indigo UV Coater, a roller-coating device intended for inline or offline use. "Very often you start talking to a customer about inline use and they decide they only need one coater and it’s more flexible to not have it hitched to a press," says HP Indigo’s UK and Ireland country manager Robert Stabler. He sees the UV Coater as an important machine for HP. "In certain applications, they’ve been crying out for this for a while. They’re what I call the image-rich applications, like photo albums or a book jacket or even greetings cards, where the quality of print is both integral to the product and gives it a longevity through improved scuff-resistance."

Inkjet impact
Drupa 2008 was billed as the inkjet Drupa, but few foresaw the extent to which inkjet would make its presence felt in post-press. Two machines in particular stole the post-press show: MGI’s JetVarnish and Fujifilm/FFEI’s Emblaze. These machines harness the power of inkjet to offer the capability of spot or flood coating, infinitely variable on a page-by-page basis. Emblaze, which uses Xaar’s 1001 variable-droplet technology, uses a single liquid (thereby avoiding the need for wash-and-swap routines) and can produce various levels of gloss by increasing its droplet size to lay down a heavier film of varnish, even achieving all three on the same sheet, according to FFEI inkjet solutions manager Robert Lugg.

He added: "We showed it a little ahead of time at Drupa, because it won’t ship until the last quarter of this year. We were right to go because the level of interest was absolutely astonishing. We reckoned it would be an eye-catcher, but what we didn’t predict was the size of the market for this machine. It seems that digital printers are really wanting to give their print a third dimension."

But, although digital printers are keen to get into the new coating technology, there is some work to do on the education front first. "As fast as buyers catch up with what digital print can achieve for them, the technology moves on," says Kodak GCG marketing director, Digital Printing Solutions, Erwin Busselot. "Buyers now know about on-demand and personalisation, but they are much less familiar with the idea that digital can cost-effectively offer value in this way."

Until print buyers become more widely aware of the capabilities of digital print, decorative coating seems unlikely to find a ready market and printers’ demand for coating units will remain low. Busselot’s opinion is backed up by the findings of this year’s Canon-commissioned Insight report on digital printing directions, researched and written by a team led by digital guru Frank Romano. The report suggested that added-value finishing plays a major part in buyers’ perceptions of overall print quality and until buyers become aware of digital’s new-found added-value finishing capabilities, their perceptions of digital print’s quality are likely to remain low.

CASE STUDY: DIALOGUE SOLUTIONS
Dialogue Solutions, based in Edenbridge in Kent, is the commercial digital specialist in the Howitt group and uses four Xerox colour digital presses to produce a wide variety Of work for clients including the Royal Bank of Scotland, pizza chain Dominos and the RSPB.

Group operations director Vincent Gidley was on the lookout for an alternative to lamination for his customers that also offered the potential for shorter runs when he hit upon the Morgana UV DigiCoater as the answer.

"It makes digital a lot more durable, but we also want to enhance our digital print with a special finish," says Gidley. He adds that the process is "a lot more user-friendly and better for the environment than lamination." Although the company runs a Xerox iGen3 with the potential for an inline solution, offline was Gidley’s preferred solution for flexibility.