By: E&P Staff
Last month, Le Monde’s printing plant in Ivry-sur-Seine presented the results of a months-long series of tests running semi-commercial work with ultraviolet-cured inks on its Wifag press.
In addition to the more than 450,000 copies of Le Monde, the plant produces other titles, including Le Monde diplomatique, Les Echos, Le Journal du Dimanche and Directmatin plus.
Wifag users and visitors from around the world were invited to observe the press and receive the results.
Participants heard presentations by specialists involved in the project, including those from Wifag, in Bern, Switzerland, UV systems manufacturer Eltex-Elektrostatik, Weil am Rhein, Germany. They also followed production demonstrations with the four-high OF 370 GTD blanket-to-blanket press, in service at Le Monde since the end of 2003.
After initial discussions by Le Monde production managers and representatives of Wifag and Eltex, the press was equipped last summer with an Eltex Innocure UV curing system, which was subsequently tested under different conditions using standard newsprint and with lightweight coated (LWC) paper. UV inks were used with normal blankets and hybrid cylinders.
Wifag and Eltex collaboration on UV curing dates from testing begun five years ago in Switzerland at St. Gallen and continued at the Neue Zuercher Zeitung. Shorter web leads, among other reasons, makes UV curing an alternative to heatset drying in newspaper printing. Wifag notes that other projects in Austria, Germany and Canada have demonstrated that UV curing works at web speeds of up to 45 feet pr second without hurting quality.
According to Wifag, components such as a pair of high-power UV modules for each side of the web, electronic switching and peripheral devices for energy-optimized cooling, air exhaust and nitrogen supply provide reliable, economical and environmentally preferable operation.
The tests showed Eltex’s Innocure process enabled UV inks to harden at the maximum press speed. The process replaces atmospheric oxygen – which inhibits the action of photoinitiators during ink polymerization — with nitrogen by applying a high-voltage plasma across the web.
At the June open house, Le Monde Production Manager Roland Chamak said that “a press can hardly be operated profitably and economically with only the daily newspaper as a core product. A broader utilization is indispensable for a higher ROI. The product must be made more attractive to readers and our product portfolio must be extended to magazines, weekly newspapers, advertising papers and inserts.”
Chamak added that the tests established “the printing and commercial limits” of complementary coldest/UV printing. Despite an often small night-time window for changeovers, he said “high process stability without variation” was achieved with vendor support and trials of different inks, blankets, rollers and paper. With testing successfully completed, Chamak said an investment decision will soon be made to enable use UV technology “in daily production.”