Offset Printing
Drupa first: 4 over 4 in large format
Tuesday 29. April 2008 - KBA optimises big perfectors for commercial applications
Four over four perfecting in large format has been available from KBA – and only from KBA – for some time. Now other press manufacturers have announced that they will also be unveiling large-format convertible perfectors at Drupa 2008. However, such systems are unlikely to attain market maturity or deliver commercial-standard quality in the immediate future, nor will they be available in the same wide choice of practice-proven configurations as the Rapidas. So KBA is making the most of its time gain to improve the operation, makeready and quality of its big perfectors for high-quality commercial applications.
Engineering a press with the quality and stability necessary for four-over-four perfecting is no easy task, which is why the large-format specialists at KBA’s Radebeul plant brought it to market relatively late compared to straight presses. A large-format Varimat press with convertible perfecting after the first printing unit was unveiled at Ipex, Birmingham, in 1993 and subsequently shipped to the USA. KBA followed this up a year later with the first Rapida 104 medium-format perfector press for four over four. Other manufacturers took much longer to include such presses in their programmes. Even so, KBA caused a minor sensation in 2002 with the first 1,120 x 1,620mm (44 x 63¾in) Rapida 162 with perfecting after the fourth unit.
At that time the very competitors who are now busy launching such presses dismissed them as niche products for the book-printing industry. And today? Fifteen years on, those who originally scoffed at the concept of big perfectors are belatedly jumping on the bandwagon and to save face are claiming that inadequate advances in pre-press technology delayed their entry into the market – an unconvincing argument considering that the technology has been up to speed for many years now. It seems they have finally realised that enhancing productivity when printing products with more than 32 A4 pages can best be achieved with big perfecting presses, and that demand in the market has picked up accordingly.
Big perfectors boost productivity
Whereas a standard B1 (41in) press can print a maximum of just 16 A4 pages in one perfecting pass, the large-format Rapidas can print 32, 48 or even 64 pages, depending on the format. Identical automation components and a maximum rated speed similar to that of recent medium-format presses mean that their output is substantially higher with the same number of personnel.
Automatic conversion in just over 60 seconds
The core component of the large-format Rapidas for four over four is the automatically convertible perfecting unit. The single-drum system deployed by KBA in this format was developed more than forty years ago and has since been continuously improved in line with the performance and output of each new generation of presses. Conversion from straight printing to perfecting and vice versa takes just over 60 seconds, complete with all the necessary changes in format. Manual tasks are kept to a minimum and depend on the substrate and the image to be printed. Everything else is controlled automatically via the ErgoTronic console. The impact of changes in the blower settings at the perfecting unit or the delivery can be checked in a video monitor at the console with the aid of up to thirteen cameras operating in real time in the press, and the settings adjusted if necessary. And, of course, it is possible to store all the job-specific settings for perfecting and air-blown sheet guidance. This further accelerates the conversion sequence when printing repeat jobs on the same substrate.
At Drupa 2008 KBA will be exhibiting a perfector version of the Rapida 162a with an even bigger sheet size. Whereas previously the printable width during perfecting was effectively 1,095mm (43in) on a reduced sheet width of 1,120mm (44in), this has now been increased to 1,170mm (46in), a full 75mm (3in) more. As a result it is possible to run the maximum sheet size of 1,200 x 1,620mm (47¼ x 63¾in) through the press in perfecting mode.
Commercial delivery for higher output
At Drupa 2008 KBA will be showing a new, high-performance package for the long perfector versions of the Rapida 142. This new-generation press was developed specifically for commercial printers keen to expand their capacity and bid competitively for high-end commercial work. The package enables the sheet guides and suction stations to be controlled remotely from the console. With these presses only five print-free corridors are necessary – 15mm (0.6in) in the centre of the sheet and in the quarterfold, and 20mm (0.8in) at the outer edges. Reducing the print-free corridor reduces the minimum run length at which production is cost-effective. Expressed in terms of area, the saving is one sheet in every 110 printed.
It goes without saying that with this high-performance package all the settings can be stored at the console for repeat orders. Non-stick coatings on the drum shells, and turbulence-free blowers located above the delivery, ensure that even lightweight stock is delivered smoothly and precisely to the pile.
Printing books, brochures, calendars and associated products on a large-format press is one thing: finishing is another. While there are binding machines fully capable of handling formats up to size 7, if the in-house bindery is only equipped to handle smaller formats an ICS inline slitter can be installed in the press to cut the sheets down to size. Stacked on two pallets, these can then be put through B1 finishing stations. However, for higher volumes and longer runs KBA recommends investing in a dedicated large-format guillotine.
Brisk demand in central Europe and North America
KBA is the world market leader in large format, with around 1,000 big Rapidas sold since 1995 and a market share of more than 60%. 15% of all Rapida large-format presses have perfecting capabilities. They include five- and six-colour versions and over 20 presses for four over four. Among the long perfectors the most popular model is the Rapida 162a, followed by the Rapida 142, but they also include a number of Rapida 130, 130a and 162 press lines. Most installations of big perfectors are in central Europe and North America, the highest numbers being in Germany and Italy, followed by the USA. But there are also four-over-four versions of large-format Rapidas in the UK, Belgium, Hungary, China and other countries.