KBA: Huge Advances in Optimizing Waterless Offset for Newspaper Production
Monday, December 10, 2001
More than 200 newspaper professionals from all over Europe travelled to Würzburg at the end of November for a three-day open house on the KBA Cortina. An update on the advances made in waterless offset for newspaper production was given in Koenig & Bauer's brand-new engineering building which, with the new R&D centre where the press demos were held, was inaugurated this year as part of an extensive building programme at KBA's Würzburg facility which will culminate in the erection of a 10,000m (108,000sq ft) production hall early in 2002. Welcoming the guests, Claus Bolza-Schünemann and Walter Schumacher, executive vice presidents for engineering and sales respectively, cited this big investment package as proof of KBA's commitment to newspapers and other print media, and its faith in their future prospects. New Approach for High-Volume Newspaper Production KBA marketing director Klaus Schmidt described the philosophy behind the Cortina, which is not just a new press but an intelligent and - in the eyes of the more conservative members of the trade - radical approach to creating a standardised, industrialised tool for addressing the expanding demands of the newspaper industry. These he summed up as more colour; a better print quality overall and a uniform quality in distribute then print; less waste, even with split editions; fewer press parameters and thus easier handling; lower capital investment costs yet greater versatility. Printer Version Fast, Precise Temperature Control The basic tenets for adopting the waterless process in coldset newspaper production were defined by Dr. Karl Schaschek, head of KBA's web press R&D, who emphasised the importance of temperature control in the inking units and on the plate cylinder for achieving the correct ink viscosity and thus pre-empting printing problems at different press speeds. Since the Cortina was unveiled at Drupa 2000 huge advances have been made in guaranteeing fast, precise temperature control at the anilox roller and plate cylinder across the entire press width. For example, fluctuations in temperature and viscosity can now be contained within tight tolerances and the full-solid densities specified in Ifra norms for the individual process colours maintained consistently at different press speeds. The fact that a linear dependence has been established between temperature and density, and between press speed and the temperature specified for the inking unit, facilitates a controlled density change, if desired, in the individual printing couples. This was proved in the subsequent press demonstration. The basic tenets for adopting the waterless process in coldset newspaper production were defined by Dr. Karl Schaschek, head of KBA's web press R&D (4) Intelligent Features Reduce Manning Georg Schneider, head of web press development and a progenitor of the Cortina, focused on the optimisation work that has been done on the press to support waterless newspaper production and reduce manning levels for routine tasks such as changing the plates, ink or doctor blades, or setting the rollers. New labour-saving features include full-width ink troughs, a system for ensuring precise registration during semi-automatic plate changes, and a full-width cylindrical doctor blade that reduces contamination. According to Schneider, the intensive tests conducted since Drupa 2000 have already resulted in design improvements in the first double-width Cortina, which is earmarked for delivery to Zeitungsdruck Dierichs, Kassel, in early April and will commence shopfloor testing with different run lengths at the end of May 2002. Some improved features, eg a roller lock that can be set from the console to prespecified target values, may well be fitted in KBA's conventional newspaper presses, and there is no reason why others, like automatic blanket tensioning or semi-automatic changing of all or individual plates across the cylinder width, should be limited to the Cortina either. KBA's waterless specialist Peter Benz described the characteristics of waterless newspaper offset from the printer's point of view and listed the large number of ink, plate and paper suppliers that are co-operating on the Cortina project. Following extensive tests with inks from eight manufacturers, a number of inks have now been formulated which support problem-free quality production in waterless offset. 130ton(ne)s of standard and improved newsprint from nine suppliers have been consumed in the course of the project with the aim of enabling virtually all the current types of newsprint to be printed in waterless offset with no loss of quality. Various makes of blankets and inking rollers have also been tested. To create a realistic workflow for optimising waterless offset and so enable customer print jobs to be handled in its new R&D centre, KBA has installed Müller Martini mailroom technology and a Kodak Polychrome NewSetter CTP system, which will be joined by a new-generation CTP system from US supplier Presstek. Peter Benz used microscopic close-ups to show that dot gain in waterless offset is very much smaller than in conventional offset. He explained that waterless also supports a higher ink density and full colour in a 60l/cm (150lpi) screen on uncoated newsprint, which wet offset does not. Over the next few months KBA will be conducting endurance tests with a threefold objective: to extend the service life of plates to more than 120,000 cylinder revolutions; to achieve a superior print quality with consumables from all the suppliers involved in the project; and to optimise the speed-related automatic temperature-control curve for the press so as to ensure that the teething troubles suffered 18 months ago - ink build-up, scumming and picking - do not recur. Versatile Print Scenarios Possible Martin Schoeps, head of the Cortina project, gave an update on proposed activities for expanding the range of options possible with this compact mini tower press. The Cortina can be configured as a floor-mounted press where headroom is limited (eg former supermarket buildings) or as an eight-high tower to expand output and colour capabilities in an existing 15m (49ft) high press hall. The possibilities are virtually unlimited, as was demonstrated by the architects' plans Martin Schoeps showed, which even included a press hall on board a ferry.