In recent times there has been a heavy emphasis on industrial segments and the more eclectic side of inkjet’s capabilities, but at this year’s European event, held last month in Barcelona, it was the cutsheet arena that was the focus of the agenda.
The biggest buzz in digital cutsheet since Drupa 2012 has been around Landa Digital, which continues to insist that the realisation of its Nanography technology is just around the corner. However, its presses and existing collaborations are still, for now, beyond the horizon.
In the meantime the offset world is getting fidgety in wanting the benefits afforded by inkjet output without compromising on existing quality and throughput speeds.
Reading between the lines it is not particularly difficult to understand why offset press manufacturers have been slow to make the shift to digital. It requires input and technological expertise from specialist developers of the components, such as printheads, that are relevant to their equipment.
Offset-digital collaborations are the hallmark of the current and coming generation of B2 (and larger) digital presses. Konica Minolta has its own inkjet expertise yet the KM-1 B2 sheetfed UV-curable inkjet press relies on Komori for its cylinder configuration, sheet transport and reverse mechanism for duplexing.
Heidelberg, of course, has its roots deep in analogue printing techniques and relies heavily on collaboration with specialist third parties – Ricoh and Fujifilm – to take its digital plans forward.
Partnerships make sense, and are also evidenced in the Ryobi media transport incorporated into the Fujifilm Jet Press 720, and Screen’s Truepress Jet SX, which uses offset principles for paper handling and positioning.
Advances in single-pass inkjet technology have been sufficiently well-honed that companies like Heidelberg, and many others, now recognise that it can compete with litho and flexo. While Heidelberg, KBA and others all rely on digital partners for their nascent inkjet presses, offset manufacturers bring their own expertise to the table.
“Heidelberg understands integration and software, web and sheet handling. And applications and getting the best channel to market are keys to inkjet, and are also our competencies,” stated Jason Oliver, Heidelberg senior vice-president, digital at the event.
Oliver, however, did not give an update on Heidelberg’s own sheetfed inkjet plans, which were unveiled in April and are due to include devices up to B1 format for commercial print and packaging. However, he did give a clue as to where Heidelberg sees the sweet spot for such devices. “There is an overlap that considers target run lengths for future digital presses, from 300 to 1,500 sheets, and this bridges the gap left currently between digital and traditional sheet-fed offset,” he says.
Principally, the key to successful transition of digital is determining cost, time and run length. But these criteria are now assisted by the efficiencies engendered by single-pass printhead capabilities. Scanning heads are not practical in a segment where consistently high throughput speeds are crucial for competing with analogue alternatives.
Sheetfed challenge
While narrow-web is a simpler candidate for conversion due to the shorter printhead arrays, B2 offset presents greater challenges, with wider single-pass arrays that must provide consistency and fast speeds without compromising on quality.
Daisuke Naka, who works in the business development division at Konica Minolta’s Inkjet Business Unit, explained that while UV inks had helped solve some challenges, there were still fundamental hurdles to overcome. “UV ink has stability and flexibility in keeping with high quality, with no need for heat fixation, so this has a lower effect on paper and the ability to duplex in the machine,” he said.
“Unlike water-based inks the possibility of the nozzle surface drying up is far lower with UV inks, and they work on a wide-range of papers that don’t need a pre-coat.
“But the technical challenge in striving to be close to offset quality lies in how to control bleed and dot coalescence, and the avoidance and compensation of streaking. These are unavoidable matters for high-speed single-pass inkjet and are more sensitive in the commercial print sector.”
There are few print houses that haven’t already invested in some sort of digital technology, whether it’s toner-based for short runs and personalisation or inkjet for wide-format jobs. The talk about what’s just around the corner will go on, but potential sheetfed users want a market-ready product now. Fortunately, the cutsheet horizon appears to be considerably closer than it was this time 12 months ago.
Marco Boer of IT Strategies summed it up: “Single-pass is driven by the desire to capture page volumes with inkjet technology.”
So these printhead arrays, already proven in the functional arena, are now playing a major role in practical productivity in inkjet presses.
