“It is not possible to handle runs fewer than 300 sheets,” says KBA sheetfed sales director Chris Scully. “It’s just not possible to remove the old plates and put the new plates in position fast enough.”
He has been watching as KBA demonstrates its flying plate change technology to an audience of UK printers visiting Germany at the end of last year. They had visited a traditional German restaurant the evening before and have already received a corporate presentation, seen other presses demonstrated and walked around the factory. This is to be the highlight of the tour – arguably the most automated sheetfed press in the world and the most productive, in the B1 format at least.
For a run of 400, 500 or 5,000 sheets, the flying plate change technology that KBA service/support/consumables has will be compelling. In the right hands and for the right application. It means that a long perfecting Rapida 106 can in the right circumstances become two four- or five-colour presses sharing the same feeder and the same delivery.
At the press manufacturer’s demonstration centre at its vast factory near Dresden, a Rapida 106 is set up to print on the first set of four units while the second set of print units is disengaged for a plate change at the same time as a job is being printed on the first units.
Once this run is completed, the plates lift off impression and the second set of print units drop into place. The press has slowed at this point, from 16,000sph to 12,000sph, but once the new plate cylinder is in place and paper is moving through the press, the press can accelerate back to full speed. Until the time comes to switch back to the first set of print units, now with a fresh set of plates mounted.
KBA’s LogoTronic press management system has downloaded the job data, while Plate Ident ensures that plates are loaded and adjusted to be in precise register. Ink density measurement delivers the required print quality and keeps it flat lined far faster than an operator can make any adjustments.
This is as close as any company has yet come to a fully automated sheetfed press. Similar technology has existed in web offset printing. The Timson ZMR, for zero makeready, is a press that works in this way for mono book work, leaving just a few metres of white paper between sections.
Goss has also delivered full colour web offset presses where four units are in use while another four units are being prepared for the next section. But outside a few duplicator style machines in the past, nobody has done this on a four-colour sheetfed press.
For both Timson and Goss, installations are limited and there is every reason to suppose that demand for the KBA sheetfed press will also be of the niche variety. But where an application exists, the impact can be devastating. Scully points to a company in the US that is producing window posters for retail customers. All are the same size and on the same paper and to respond to client requirements are being produced in ever shorter runs to create a poster that can carry messaging relevant to stores in that area rather than the same generic message.
The printer can run the same material, the same settings in feeder and delivery and thanks to flying plate change can keep running. This cuts turnaround times for the client and means the printer can do more with a single press than competitors can do with several machines. “Nobody can touch him,” says Scully. “It is about volume printing across a multitude of small jobs.”
The press has UV drying included so that sheets are fully dry in the delivery, ready to trim and ship. The onboard colour control systems will have the sheet in colour within 35 sheets from a standing start, fewer when the press is already inked up.
It is possible to conceive of online printers looking for this sort of capability, but the more likely users are going to come from the book and journal world where short runs combined with the cost and ongoing quality concerns with inkjet colour printing, could make this an interesting option. Provided the overall volume exists of course. It certainly set one UK printer on the trip thinking about the logistics and the economics of printing like this. Offset litho might yet strike back against the onward march of inkjet printing.
The same technology is essentially available as a straight press, when simultaneously plate changing, Plate Ident and so on strip job turnaround time to an absolute minimum. In this case the time for a plate change is hidden by the time for a cylinder wash up, something that has been automated and which takes a couple of minutes.
As the plate change takes place simultaneously as the wash up, says Scully, this means there is zero time for a plate change. This will be powerful enough for the vast majority of commercial printers increasingly seeking to squeeze two machines’ performance from a single press.
As with every press supplier, a machine can be equipped with a choice of drying technologies. The conventional VariDry dryer recirculates the hot air used to both cool the IR lamps and to add a little more to the process. It cuts energy consumption by 50% for a commercial printer. But not as much as LED UV, the company says.
KBA has a long association with conventional UV for packaging applications with all manner of lamp configurations according to the specific requirements of a particular customer and his application. LED UV remains new. Nevertheless, says Scully, “we believe LED is the future”.
To date the take has amounted to two presses installed, at Blackmore and now at J Thomson Colour in Glasgow. Others are in the offing and there are plentiful installations in Germany, France, Switzerland and other locations around Europe. The sheet is delivered dry for immediate processing and there is no need for spray powder or a coating to seal the print from marking.
For a long perfector, the advantages extend to removal of the anti mark cylinder jackets for the second set of print units and the elimination of any need for gutters to accommodate slow down wheels in the delivery. There is also the ability to stretch the print length by 0.1mm using the servo motor technology to make micro adjustments to the speed of a cylinder for precision in register on the second side.
KBA can run its presses at 20,000sph. This is possible elsewhere as feeders can operate at these speeds, but is not advertised. This level of throughput starts with the SIS infeed which uses electronics to shift the first set of grippers to meet the sheet, rather than using a side lay system to present the sheet into the first set of grippers. It reduces any tendency for sheets to bounce at these high speeds. From there the engineering and gripper design moves the sheet through the press as smoothly as possible.
The full range of quality control systems measure densitometrically and monitor for flaws in any sheet. At a complete makeready, the sheet will be in colour after 35 impressions and ready to go in 90 sheets.
On a packaging press, or one used to print sensitive documents, playing cards or pharmaceutical leaflets for example, there is the option of QualiTronic PDF. This assesses every sheet against the PDF supplied by prepress to make the plate.
If there are deviations from this, it might indicate that a figure is missing from the list of ingredients, or that there is an unwanted mark in the glue area of a carton. One is crucial to the acceptance of the job, the other is not. Consequently the PDF can be masked so that only the integrity of information in the important areas is checked. A report is generated to identify where a problem was spotted on which sheet.
QualiTronic Professional is a step down and starts with a comparison of the printed sheet against the PDF, but once a sheet has been signed off, this becomes the standard against which subsequent sheets are monitored for quality.
These are the sorts of features that are necessary in high speed high production set ups where press operators need as much assistance as technology can provide to ease the pressure they are under. Otherwise productivity towards the end of a shift dips and errors can be missed. On the monitor, the LogoTronic displays an image of the next job along with the number of sheets to be printed and identifies the paper to be used. There is no room for mistakes or lack of clarity in this type of operation.
The new feature which tantalised most was a coating tower containing three anilox rollers. With different cell depths, these can be switched from one to another in the same two-and-a-half minutes as the press is washing up. The printer then can choose the level of coating to be applied, a thin layer for sealing work to a heavier layer for an aqueous varnish.
If many printers try to batch jobs that require a similar level of coating together to avoid the hassle of changing the coating cylinder, this removes the problem. Needless to say the coating plate is removed and loaded just as swiftly.
KBA UK had organised the trip as a reminder of what had been shown at Drupa, and such developments as inline cold foiling, rotary die cutting and the Varijet inkjet carton press received due mention. They are indications of the spread of the company’s activities. For the commercial printer there was already enough to digest, even without a plate of pork and dumplings the night before.