Heidelberg is preparing to roll out a new screening technology that can save ink, reduce energy consumption and improve print quality. This is Multidot, a collaboration between Heidelberg Poland and a university in the country. It will be offered as part of the Prinect workflow.
The technology was introduced to those attending the Prinect User Days at Heidelberg 11 months ago. At that stage Multidot was still undergoing field testing and the eight users were restricted to Polish printers. Selected feedback from these printers formed part of the presentation of the technology.
Since then the user base has included printers in Japan where the technology has proved as effective as in Poland and where many printers are using UV inks for both packaging and commercial work. More recently Multidot has been introduced to printers in South Africa.
Word is now spreading further and samples of Multidot screening and a presentation were on hand at Heidelberg UK’s recent Digital Open Day.
The system works by using a group of different shaped “micro cluster structures’ to replace the conventional elliptical shaped dot used in conventional screening, while retaining the conventional screen angles.
This gives an open structure for the application of ink on the substrate and uses the effect of a shadow around each of the micro clusters which absorb light and create the illusion that this shadow area has received ink. This accounts for impressive ink savings that have been reported by those using the technology. In last year’s presentation, savings of up to 45% were claimed. Heidelberg UK is more likely to talk about average ink savings of 18-20%.
This is not the only advantage of the technology, albeit the one that has the most direct benefit. Because less ink is applied, there is a saving on water use and a saving in energy needed to dry the sheet.
The size and shape of the micro clusters is determined by the software and has been optimised to reduce moiré effects. The technology results in an expanded gamut range over a standard CMYK, brighter images and improved accuracy on details.
This also means that a printer can achieve these results while running a coarser screen ruling than normal, say 150lpi rather than above 200lpi. This also makes the press easier to control and in turn this will increase OEE so reducing start up waste and makeready times.
