The weekly Verdigris blog by Laurel Brunner
For years the graphics industry has been improving its environmental footprint, but not shouting about it much. Heidelberg’s introduction of LED drying technology for the European market is a case in point. LED drying of UV inks is an energy saver in more ways than one.
LED technology has been around for many years and turns up in all sorts of applications, from car headlights to jewelry. (It’s just a matter of time before we see LED piercings.) In the graphics industry LEDs are used for curing UV inks in both analogue and digital printing systems. The technology has many advantages including low energy consumption and long life: the LEDs Heidelberg is using have a lifespan of over 25,000 hours. LEDs emit no heat or ozone; they are compact and relatively inexpensive.
However the technology’s not perfect because it’s constrained by limited wavelength and the need to focus the light very precisely. LEDs need to be used in quantity to be effective, so development costs can be steep. Its slowness and insufficient depth of cure have also been barriers. Implementations in the printing industry must deliver complete drying or curing without creating any adverse chemical reactions, such as ink migration.
These limitations are partly why LED technology has taken a while to get into the field. But with the uptake of UV inks for all sorts of substrates from film to board, the use of LED curing is becoming less of an oddity. It delivers handy commercial benefits because the prints are immediately dry and ready for finishing. The short runs and multiple changes typical of today’s industry require rapid processing of prints. Systems such as Heidelberg’s DryStar LED for sheetfed offset presses can deliver a competitive advantage, as well as being energy efficient and cutting consumables costs. Heidelberg’s first European DryStar LED installation is at Abächerli Media in Switzerland. The company has the world’s first Speedmaster XL75 with Drystar LED.
DryStar LED works on presses printing up to 18,000 sheets per hour and in Japan Heidelberg has already installed over 20 systems with DryStar LED over the last two years. The company expects to start installing the technology in the US later this year with the rest of the world shortly after that.
The savings LED can deliver in terms of energy and consumables is starting to balance the higher cost of the inks: as more such inks are produced the price is dropping. The environmental savings are clear. LEDs use less energy and have a longer life than the mercury arc lamps they replace. They are the way forward for UV ink curing.
– Laurel Brunner
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