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Modern offset presses need special consideration

6 August, 2018 - 09:39 -- tbrunner

It seems so simple, you invest in new technology that’s got a lower carbon footprint and you’re making a more sustainable choice. And achieving a lower carbon footprint is a lot to do with why companies invest in upgraded digital presses, new computer-to-plate systems and even processless plates, such as Kodak’s Sonora. But what are the knock-on environmental effects of new, more sustainable technologies? It’s a problem not only for technology investments, but for everything we do that is intended to be environmentally friendly.

In the case of UV-curing litho presses, which generally have interstation curing, the on press chemistry can vary and this has to be accounted for in environmental impact evaluations. Litho presses have used UV curing for longer than pretty much any other printing method. The science is well-advanced for both web and sheet fed presses and such presses produce many applications on many different substrates. UV-curing litho presses presses are generally more expensive to own and run than conventional offset presses, but they are considered to have solid advantages that translate into improved margins. Drying is instant with UV curing inks so there are no delays prior to finishing, which can mean a two to three days saving compared to prints printed with oil based inks. UV cured inks stick to pretty much anything and there are virtually no VOC emissions associated with them, so no additional venting is required in the press hall. The prints can be of very high quality and be resistant to mechanical degradation and chemicals. But it’s not an entirely rosey picture.

UV inks behave very differently compared to conventional oil-based inks, so every production component has to be compatible, including fountain solution and the printing plate. If any of the settings on press are set to run conventional rollers and blankets say or minders use conventional cleaning materials, things can quickly go awry. On press chemistries that are incompatible with UV-curing inks can mess with the printing plates and compromise run lengths, sometimes cutting plate durability very substantially. With hybrid presses, press maintenance and process control is even more important. Some printers we have heard from have experienced a noticeable loss of quality on the plates and have had to replace them after a few thousand impressions. For a job that’s 10,000 impressions long, that’s twice as many plates, and for a run length of 40,000 it’s four times as many adding a load of cost for not much gain.

This obviously has a severely negative environmental impact as well as a severely negative margin impact. It means more plates, more processing chemistry, more stopping and starting the press for plate changeovers, and additional energy emissions. The moral here is to consider the environmental benefits of a given technology in the wider context of overall system environmental impact and to adjust things so that you optimise both the technology and its environmental impact.

– Laurel Brunner

This article was produced by the Verdigris Project, an industry initiative intended to raise awareness of print’s positive environmental impact. This weekly commentary helps printing companies keep up to date with environmental standards, and how environmentally friendly business management can help improve their bottom lines. Verdigris is supported by the following companies: Agfa Graphics, EFI, Fespa, HP, Kodak, Kornit, Ricoh, Spindrift, Splash PR, Unity Publishing and Xeikon.

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