Bluetree forges ahead with inkjet drying in litho race

16 Oct 2018
Topics: inkjet, litho

The Screen inkjet presses with Tecnau unwinders - complete print to finish workflow is faster and cheaper than litho


Bluetree Group is the first UK site to benefit from new near infra-red (NIR) drying in its Screen Truepress Jet 520HD inkjet presses. 

At an open day last week, co-hosted by suppliers Screen, Tecnau and IFS, the Rotherham-based trade printer which operates the Route 1 Print and brands, explained how it is using Screen's inkjet presses to produce work more cost-effectively than litho alternatives.

'The Screen press is more productive than a B1 press all in - a Heidelberg plus CtP, guillotining and folding versus the Screen plus Tecnau line at one third of the cost. On a perfect bound book 500 run, it was two-thirds of the cost on materials too,' noted managing director Adam Carnell, adding that the staffing requirement for the digital production route was two versus six for the litho one.

Part of optimising the inkjet press workflow is in the post-print drying stage. Screen Europe's Cees Rem explained, 'The drying challenge is to remove water from the ink, not from the paper, which increases tension in the sheet that can lead to cockling or wrinkling. Drum-only drying can dry the inside of the sheet, which can be problematic with thin stock.'

Screen's solution adds an NIR dryer to the heated drum and "air knife" approach in which the layers of moist air above the wet ink is blown away continuously. The NIR unit is tuned to a specific wavelength that Mr Rem said means that 90% of the emitted energy goes into drying the ink and not the paper. 'This allows faster production speed, with near-instantaneous fixing of the ink,' he added.

Also key to optimising throughput from the Screen presses is pre- and post-press equipment form Tecnau. This includes two Roll 9 unwinder and web cleaner units feeding the presses, plus Double Cut & Stack 2325 cutter/stacker systems with "soft touch" grippers that avoid scuffing or handling marks on the printed sheets by handling by the edges only, a feature that Mr Carnell said swung the finishing equipment choice to Tecnau rather than Hunkeler. Book binding and other finishing tasks are handled by a variety of Horizon equipment, also supplied to Bluetree by IFS.

Bluetree is also using a Tecnau SheetFeeder IG roll-to-cut system to provide bulk sheet feeding to one of its four Xerox iGen toner presses. This enables continuous operation for up to eight or more hours from a single paper roll without requiring lifting of stacks and can reduce paper costs. A version for the Xerox Brenva sheet-fed inkjet press is also in development, said Tecnau's Harm Jan Hulleman.

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