Sheetfed Sheds Some Gears

As its name indicates, the new Roland 700 DirectDrive sheetfed features MAN Roland's DirectDrive system, which was introduced as a prototype at drupa 2004. The innovation uses computer-controlled servo-motors to power the plate cylinders in its printing units.

Isolating the plate cylinder from the press's main drive allows a number of time-consuming makeready chores to be completed simultaneously. Example: all of the plates can be changed on the Roland 700 DirectDrive at the same time wash-up takes place, effectively resulting in zero plate-changing time.

To unveil DirectDrive and the Roland 700 HiPrint press—which offers an array of in-line production options— MAN Roland hosted an event for customers and journalists last month, at its sheetfed press operation in Offenbach, Germany.

“One segment of the printing industry that the Roland 700 DirectDrive is aimed at consists of short-run, high-performance printers,” says Dr. Markus Rall, the MAN Roland board member in charge of sheetfed presses. “These are facilities that have to makeready and print over 10 jobs per shift, with average run lengths below 5,000 sheets per job. To be competitive, they have to drive costs out of their workflows. DirectDrive will let them achieve major savings by essentially taking the time it takes to plate the press out of the production process.” Rall points to a second application sector as prime territory for the Roland 700 DirectDrive. “It is also ideal for users of long perfectors with eight, 10 and 12 printing units, who produce a high volume of perfecting work,” he says. “It can reduce their makeready time by as much as 60%, and even more if they have the QuickChange modules such as closed-loop inking.”

Direct drive has been a standard feature with MAN Roland's shaftless commercial and newspaper web offset presses for a long time. A different method was needed for replacing sheetfed gear drives. The solution was direct drive of the plate cylinder, which is declutched and driven by a high-torque motor mounted on the cylinder journal.

This results in an enormous reduction in makeready times: plate changing takes place in the background while other makeready processes, such as inking-up, are being attended to. With a small job changeover on a long perfector, a new language version of a brochure for instance, or for the next signature of a larger 4/4 product, the printer only needs to wash the blankets, which takes around four minutes. The plates are changed simultaneously in all printing units while this is being done, whether there are eight or 12 plates.

What happens when the ink needs to be changed? Inking units and the blanket and impression cylinders must be washed at different speeds. Inking units can be washed at high speeds—up to 9000 rph. The blanket and impression cylinders have to be washed at a slower speed. The brush-type or cloth-type washing units are said to produce the best results at around 600 rph. With DirectDrive, the plate cylinder drive takes care of the fast inking unit wash-up, and during this time, the press main drive takes care of the slower washing of the blanket and impression cylinders.

Any inking units not in use can be shut down, so there's no need to apply idling grease, which must be washed off later—a chore sometimes required with long presses. With the DirectDrive, one has complete freedom with circumferential register adjustments. www.manroland.com