Commentary & Analysis
At drupa, KBA’s RotaJET 76 Digital Inkjet Press Will Reveal Deep Roots in Web Offset Production
KBA’s venture into digital printing with its new RotaJET 76 inkjet web press has origins in a market that the company knows well: high-volume offset web production.
By Patrick Henry
Published: April 26, 2012
KBA hopes that its venture into digital inkjet printing will take it into new territory, but the journey has its origins in a market that the company knows well: high-volume web production.
The recently unveiled KBA RotaJET 76, which is to be a part of KBA’s exhibit in hall 16, stand C47 at drupa, is a digital web press with distinct technical roots in the offset lithographic commercial and newspaper web presses that the company also manufactures. These antecedents, says the company, are as key to its competitive differentiation as any of its digital features.
No other litho press manufacturer currently has a non-impact digital printing system of its own development commercially available, although we expect to see technology demonstrations of this kind at drupa. Because of its long history in conventional web presses, KBA is approaching digital production “from a different starting point” than other makers of digital printing equipment, says Oliver Baar, project manager for the RotaJET 76.
These suppliers, according to Baar, are attempting to break into mid- and high-volume production as a step up from the short-run printing technologies that they first brought to market. He says that KBA, on the other hand, already knows the ropes of long-run web output and can natively build that capability into the paper-handling performance of the RotaJET 76.
Tension Is a Good Thing
The distinction, as Baar explains it, rests on one of the least “digital” aspects of the press: its mechanical ability to maintain precise web tension at high operating speeds. The unwinder and infeed unit have been designed specifically for the RotaJET 76, and web tension is controlled automatically throughout the run. Baar says that these features, along with the elimination of turn bars, serve to protect four-color register, minimize web breaks, and, as a result, maximize productive uptime.
“If anybody knows how to move paper through a press, it's KBA,” says Barr. Paper, in web widths up to 30.7" can move through the RotaJET 76 at speeds up to almost 500 feet per minute. This is equivalent to 85 million or more A4 pages per month—a volume that the press will be fully capable of delivering, says Baar, thanks to its high availability in heavy-duty use.
The RotaJET 76 prints in four colors of water-based pigment ink without bonding fluid (required as a pre-ink laydown in some other inkjet presses to guarantee adherence). KBA recommends printing on coated and uncoated media that have been optimized for inkjet printing, although, according to Baar, testing has shown “promising results” with standard offset papers as well.
For duplexed four-color printing, webs pass through two arrays of 56 inkjet heads in an arch over large central impression cylinders that can be moved aside for cleaning and maintenance. The piezo printing heads, which can vary the size of the ink droplets, give the press an ouput resolution of 600 dpi.
No Speed Bumps for Variable Data
Baar says that with the help of a digital front end featuring an expandable RIP and support for Adobe's PDF Print Engine, the RotaJET 76 has full variable data printing (VDP) capability even at the top end of its running speed. Demos of personalized printing on the RotaJET 76 are planned for drupa.
Visitors also will be able to see the press operating in conjunction with a SigmaLine digital production system from Muller Martini. The setup, consisting of a variable-format SigmaFolder and a Primera Digital saddlestitcher, will turn digitally printed output from the RotaJET 76 into magazines and advertising brochures, folded and stitched inline.
Baar says that these products, together with books, manuals, and direct mail, represent the kinds of printing best suited for the RotaJET 76 in mid- and high-volume production. KBA does not see transactional printing as a likely application, although the press would be up to the task of producing work of this kind.
KBA will be ready to take orders for the RotaJET 76 at drupa and plans to begin shipping the equipment early next year.