And yet digital is of course continuing to make great strides in rivalling litho on quality and speed, and so, of course, the sorts of runs lengths and jobs it can deliver. Not content with creating a new short-run market, inkjet printers have in wide-format printing gone on to evolve and so eat into the screen print market. Now, by all accounts, inkjet has the higher volume jobs swiped from screen printing a decade or so ago by litho, firmly in its sights. 

The most concrete evidence of this came at Fespa London last summer, when Durst revealed it was working on single-pass technology for wide-format graphics printing. The rationale behind the plan is simple. Though Durst’s latest machines are no slouches, with the Rho 1030 already capable of a category-defining 1,000m2/hr, the thing deemed to be holding back top speeds now is the technology’s scanning system, where layers of print are built up with as many as 18 passes. The sort of single-pass technology already deployed in other processes and in smaller inkjet systems, could it seems be the key to wide-format digital finally rivalling litho. 

Indeed Durst apparently isn’t the only one to think so. While reluctant to offer any specifics on record, wide-format big hitters including EFI, HP and Inca have all admitted to assessing the technology. And enough specifics have been given on a more informal basis to those printers most likely to be early adopters, PrintWeek is reliably informed, to suggest the first products aren’t that far off. 

“Because there is so much offset that is an obvious natural progression for digital. Any firm running a lot of 500 run jobs on a KBA 205 – that is the market,” says Inca R&D deputy director Phil Heylen.

EFI’s vice-president for inkjet solutions marketing Ken Hanulec agrees: “The promise of single-pass is to move the crossover point – it may be 500 today, but single-pass may get that to 1,000 or even 2,000 sheets. That enables you to switch off your screen lines, and possibly offset too.”

The question of course, is why a wide-format printer would want to switch off perfectly good screen and offset lines. For such reinvestment to be attractive, technology has to be bringing something new to the table, not simply the same speeds and quality. The ability to offer everyone different print may not, some might point out, be enough of an incentive for this, begging the question of whether single-pass wide-format printers will need to offer even greater speeds than litho.

With the benchmark for litho the KBA Rapida 205, which with a speed of 9,000 sheets per hour flat out and a sheet size of 2,050x1,050mm can theoretically churn out 27,000m2/hr – some 30 times the throughput of the latest high-end flatbeds such as the Durst Rho 1030, HP Scitex FB 10000 and Inca Onset S50i – single-pass digital printers seem to have their work cut out for them.

Other benefits

But assuming single-pass wide-format printers will have to exceed or even match litho speeds is perhaps to underestimate the benefits digital technology can bring.  

A key one is the amount of waste saved. Litho start-up waste can be considerable, typically in the hundreds of sheets, which when runs are under a thousand is a big deal. It’s a painful cost regardless of the material printed, but with more expensive substrates it becomes more of an issue. And with clients increasingly also pushing against waste as part of their sustainability policies, the case for technologies that eliminate this is becoming ever stronger. 

And crucially, it’s not all about the flat-out square metres or the printing beds per hour speeds quoted in manufacturers’ specs. Speed of processing can be achieved in many different ways. And digital has plenty of tricks up its sleeve to bring overall processing time down.

For SP Group operations director Mark McCleery it’s all about saving time and money and reducing waste, and digital presses taking on the remaining large-format litho and screen printing is a way to achieve those aims. “We’re actively migrating litho and screen print jobs onto digital wherever possible,” says McCleery. “There’s no need for plates or stencils and no set-up time or waste.”

“A digital machine wouldn’t have to be the same speed as the litho press it replaced,” agrees Augustus Martin joint managing director Lascelle Barrow, explaining that this is because the overall time to get jobs through the factory is more important than raw printing speed. 

“Increasingly we need to offer same day turnaround for reactive campaigns,” says SP Group’s McCleery, adding that this means it is more important to consider the total workflow from pre-press, through materials handling, press set-up, printing and finishing.

One area where digital scores over litho is the ability to print direct onto a wider range of rigid materials, eliminating the time and cost of a lamination step, which litho needs for all rigid and any flexible sheets over 1mm. 

And the overall holistic speed of a new single-pass machine would no doubt benefit from the other numerous features digital vendors are constantly working on to address throughput without necessarily increasing printing speeds. Examples include the introduction of zoned vacuum beds, staged media loading and automatic or three-quarter automated media handling.

“The faster the machine, the more you have to consider it as a system including the media handling and to look at maximising overall throughput. The wrong handling system could have a major impact on productivity,” says Inca sales and marketing director Heather Kendle. She reports that Inca is currently working with German firm Hostert on full automation for the Onset range, and about to enter beta testing of a system.  

Quality questions

Single-pass wide-format printers won’t, then, necessarily struggle on the speed front. Where they’re likely to fall down is delivering the desired quality at an acceptable price point. 

The latest generation of fast flatbeds have made great inroads in both quality and speed specifically because the number of passes can be upped for higher quality jobs, and reduced where speed is priority. To achieve the kind of quality now in the reach of the EFI Vutek HS100, HP Scitex FB10000, Durst Rho 1012 and Inca Onset Q40i, and so the kind of quality now expected from digital, would require many more printheads. More printheads would be needed to cover larger width and so achieve the nozzle density needed for high quality, and to enable production to carry on should a nozzle drop out.

Printheads, of course, make up a large chunk of a press’s price tag, and so any high-quality wide-format single-pass printer would currently be beyond anyone’s budget. 

“Even if a machine meets our size, quality and speed requirements, if it is too expensive we won’t make an adequate return on investment,” reports SP Group’s McCleery. 

“Capital is scarce, so machines need to meet tough criteria. We have rejected machines that didn’t stack up.”

As it stands, then, any wide-format single-pass machine developed would be confined to being “a bit of a one-trick pony, with a fixed size and resolution,” in the words of Inca’s Kendle. In short, it would be unsaleable. 

But this won’t necessarily always be the case. Inkjet printheads are subject, like most IT technology, to something similar to Moore’s Law, and can therefore be relied upon to keep delivering more bang for their buck as time goes by. 

It might well be, then, that wide-format vendors have more to say at least about development plans and when single-pass might come to pass, as soon as this year’s Fespa Munich in May. With the efficiency and waste reduction case for switching from litho to digital for high-volume wide-format work apparently well-established in many printers’ minds, the case for developing this technology is after all strong.

“Single-pass doesn’t make sense at the moment,” concludes EFI’s Hanulec. “But in the future it will – absolutely.”   

History of single-pass

Single-pass printing has been around since the inception of inkjet technology, when eggs and other coding and marking applications were its bread and butter. Over time, width and quality have increased. The first single-pass full-colour machines, which evolved into the Agfa Dotrix, and Scitex Digital Printing’s Versamark Business Color Press (which subsequently evolved into the Kodak Versamark machines), were shown around 2000. Slightly later was Inca’s FastJet. 

To date the width barrier is about 1m. Examples include HP’s T400 inkjet web press for transactional, DM and book printing, the Memjet-based wide-format machines from Canon, RTI and Xerox for CAD, and industrial machines from the likes of Durst and EFI Cretaprint. 

In commercial printing Screen and Fujifilm both have single-pass B2 machines both unveiled in 2008, while a number of others were previewed at Drupa 2012, including Konica Minolta/Komori and MGI. That was also where Landa Nanographic raised the bar with its B1 concept. Single-pass inkjet is also found in labels for web widths up to 330mm, with Durst, EFI, Domino, FFEI and Heidelberg’s Linoprint active here.