Shaking superlarge offset out of its 40-year torpor
In recent years, KBA’s acknowledged competence and market dominance in large format have prompted calls from many players in the global graphic arts industry – foremost among them printers and publishers of posters, books and packaging – for a new generation of presses capable of handling even bigger sheet sizes.
The last wave of innovation in SLF (superlarge format) offset technology dates back to the sixties, and however impressive the equipment may have been at the time, it can no longer keep pace with market demand for high-speed makeready, easy handling and integrated workflow compatibility. The measure of performance has moved beyond format to the level of automation and the cost, productivity and flexibility benefits that this can bring.
No Half-Measures
These were the properties on which our design engineers focused when developing the new Rapida 185 and 205, taking as their benchmark the advanced automation and user-friendly features that have made the medium- and large-format Rapidas universally popular. The Rapida 185 can print a sheet measuring 1300 x 1850mm (51” x 72¾”), the 205 a sheet measuring 1510 x 2050mm (59½” x 80¾”). But they are not just ‘expanded’ versions of the 1120 x 1620mm (44” x 63¾”) Rapida 162 and 1200 x 1620mm (47¼” x 63¾”) Rapida 162a. Far from it: the laws of physics necessitated a totally new design, allowing our Radebeul sheetfed offset specialists to give full rein to their inventive genius and formidable know-how.
Format-Focused Features
A sheet pile for the 205 can weigh as much as 3 tonnes (3.3 tons), and this load must be borne by the pile board in the feeder. The systems used by most manufacturers would tend to jerk as they transport the pile: our superlarge presses boast a new shaftless AC four-drive feeder which transports the pile in one smooth, continuous movement. It is now a standard specification for medium and LF Rapidas. The same technology is even being used to drive the auxiliary pile in nonstop feeders. The suction head and suction-tape feed table are also driven by servomotors, which helps eliminate vibration.
Another, more familiar, basic feature of Rapida presses is the remote adjustment of front and side lays. This, too, has been incorporated in the 185 and 205.
The printing units closely resemble those of the Rapida 162. After all, why change a design that has proved a winner on more than 2,500 units? As on the smaller press, roller contact in the fast-reacting ink train can be interrupted at two points to prevent ink surge after throw-off. Another feature much valued by operators of other KBA sheetfed offset presses – adjustment of ink-distributor timing from the console, to correct ink fade – is also to be found in the new larger versions, as is ink profile storage. Easy handling includes the ability to disengage idle inking units from the console. This reduces the volume of cleaning agents consumed, which in turn reduces VOC emissions. It also saves on energy and prolongs the service life of the rollers.