The IR/hot-air drying system
Boasting a raft of technical advancements and in the meantime fully operational, the RotaJET 76 inkjet web press unveiled by Koenig & Bauer AG (KBA) at drupa just nine months ago was also able to convince the audience on its first appearance at the Hunkeler Innovation Days in Lucerne.
Given the relatively short development lead time, the prototype of the KBA RotaJET was still not able to demonstrate its full print quality prowess at drupa, but the intervening months since the fair have seen some decisive optimisation of the ink feed, ink system, screening and colour management. Thanks to very close and intensive cooperation with potential first users from the most varied market segments, the high-speed digital press is now ready for the market. In Lucerne, the KBA RotaJET gave live proof that it has more than bridged any gap to the competition. KBA has also received similar feedback from interested printers who have tested the print quality with jobs of their own either at KBA or other digital print providers. A new rewinder and a new, even more efficient IR/hot-air drying system – both in-house developments from KBA – enhance overall performance and were already integrated into the RotaJET to be seen in Lucerne.
New polymer-based ink reduces capillary effect
An important share in the vastly improved print quality is due to the newly developed polymer-based pigment ink RotaColor. Compared to conventional inks, it significantly reduces the capillary effect (penetration of the pigments into the paper), and that translates immediately into exact print and reduced print-through. KBA is the first manufacturer to use the new polymer-based ink in a high-volume inkjet system. According to the KBA experts, the new ink extends the printable range of untreated papers and offers considerable potential for further quality advances and cost savings in the future. This was also demonstrated admirably by the variety of products printed at the Hunkeler Innovation Days. Project manager Oliver Baar: “We have kept the promises we gave to those interested in the press at drupa. The KBA RotaJET is now well prepared for daily print production.”
Superior precision engineering …
KBA sees essential advantages for the RotaJET 76 compared to competitor products in its precision engineering and the exact web travel. That is the basis for very accurate front-to-back and colour register, for example. The possibility to print during acceleration and deceleration of the press also brings a noticeable reduction in waste. KBA marketing director Klaus Schmidt: “It was for good reason that we decided to rely on our own wealth of press engineering and print technology know-how for the RotaJET, rather than simply relabelling one of the many OEM products on the market. KBA customers expect a press which stands up to the tough demands of industrial use, and at the same time does its job reliably, precisely and with ultimate availability even when operating at maximum capacity.”
As one of the leading press manufacturers, KBA will naturally pursue the topics of print quality and substrate flexibility further, and plans to bring high-speed inkjet printing as close as possible to offset. The medium-term objective is maximum flexibility for the users, enabling them to serve not just a limited market segment, but rather the full spectrum of today's print products with the RotaJET 76. This will involve also continued improvements with regard to process costs, full page-to-page content variability and the impressive format flexibility. The unique combination of capabilities embodied by the RotaJET make it an especially attractive alternative to other analogue and digital sheet printing systems for many applications.
... with interesting options for professionals
The image of a digital print system built for professionals by professionals is upheld by the availability of a web remoistening unit and a coater. The automatic reelstand KBA Pastoline is another interesting option which is not available in this form from any competitor. With the facility for flying changes, the autosplicer lends a considerable boost to performance and can also be integrated into an automated paper logistics set-up with KBA Patras. High-speed inkjet printing with the RotaJET is in this way lifted to previously unknown levels of productivity.
High-speed inkjet with a small footprint
The KBA team was initially none too happy with the very limited space provided at the Hunkeler Innovation Days. As a newcomer, the company had been allocated an area of just 91 m² for its 25-tonne high-speed press (3,000 A4 pages/min.; 85 million A4 pages/month). And that for the press with the greatest output at the show in Lucerne. On the other hand, the small stand did underline the compact design of the RotaJET. Thanks to an intelligent web lead, the press and rewinder are together just 10.5 m long and 6 m wide. It would not have been possible to install other 4/4 presses of this performance class in such a small space.
For its entry into the digital print market, KBA will at first be focussing on the target segments books, direct mailing, manuals, advertising, newsletters and newspapers. The live demonstrations of book production and a daily exhibition newspaper with original content from the “Neue Luzerner Zeitung” were among the highlights of the show. The book sections were produced reel-to-reel on the RotaJET and then combined with ready-printed offset covers on a Hunkeler finishing line. The finishing of the exhibition newspaper was also handled by post-press systems from Hunkeler.
The packaging and security printing segments are to be addressed later. One field which KBA excludes for the RotaJET, however, is the transaction and transpromo market which has evolved in the electronic business world. Printers interested in the new possibilities for digital print are offered break-even calculations and production scheduling analyses to assist their investment decision.