THE highly versatile Speedmaster CD 74 half-size format press from Heidelberg was shown at the recent Drupa exhibition with an optional perfecting system.
This enables high-quality printing on both sides of the sheet with short change-over times between paper and board and from the straight printing mode to the perfecting mode.
Depending on the job mix, an increase in productivity of 15 to 25 per cent over the traditional perfecting presses on the midsize market can be achieved, according to Andreas Sommer, Heidelberg Australia 's head of sheetfed solutions.
He said that the target groups for the Speedmaster CD 74 perfecting models included packaging and label printers, as well as commercial printers handling a wide range of printing stocks.
Heidelberg had developed the Speedmaster CD 74 for commercial and packaging printers. It was available in two formats, the C-Format 53 x 74cm compatible to the SM74 range and the bigger F-Format 60.5 x 74cm making room for another row of multiple ups for many packaging jobs, thus achieving extra productivity.
"Presses fitted with perfecting technology can make a significant contribution to increasing productivity, particularly in the packaging sector and especially as more and more applications are being printed on the reverse side in this sector, for instance boxes for cosmetics or blister cards," he said. The three-drum system newly developed for the CD 74 enabled even printing stocks up to a maximum thickness of 0.8 mm to be processed reliably in perfecting mode.
"The maximum print speed both in straight and perfecting mode is 15,000 sheets an hour. The CD 74 with a convertible sheet reversing device will be available in four- to six-colour models, with or without a coating system.
"All models are versatile all-round presses and support fast set-up, simple automated operation and reliability during the production run, even with frequently changing printing stocks of all kind of substrates," Sommer said.
A press with this capabilities could be the ideal supplementary press to a existing 70 x 100 press range in packaging, especially as run lengths were getting shorter.
The fact that half the sheet size also meant half the waste in make readies could make the difference. Profitability studies had shown that the Speedmaster CD74 was the more profitable solution for runs of 5000 40" sheets or less than a 70 x 100 cm press.
Medium-sized print shops often only had one press in the 50 x 70 cm format range and therefore demanded maximum flexibility, whether for straight or perfecting printing,
The tried-and-tested three-drum principle had been complemented on the CD 74 with sheet reversing device by a raft of new innovations.
An ingenious double-sized transfer cylinder had been fitted in front of the storage drum. This took the sheet from the impression cylinder of the printing unit located before the sheet reversing device and guided it towards a double-sized storage drum.
The storage drum had all the features of the tried-and-tested Heidelberg sheet reversing device, such as the rotary sucker system which aligned the sheet perfectly. An eccentrically shaped single-sized reversing drum with a pincer gripper bar then guided the sheet in the gripper closure to the following printing unit.
"The result is a high level of register accuracy, and this register accuracy is now available for a greatly increased range of printing substrates," Sommer said.
In straight printing mode, the CD 74 perfecting press behaved like its sister model without perfecting system and with the AirTransfer system fitted as standard between the printing units. Heidelberg introduced the new Speedmaster CD 74 with double-sized impression cylinders and AirTransfer system between the printing units in 2000 for printing rigid materials up to 0.8 mm thick.
"The variable AirTransfer system was developed specifically for perfecting printing and it is in this mode that it shows its full flexibility. Segments are operated fully automatically and support sheet travel between printing units. What's more, the new generation of high-finish impression cylinder jackets PerfectJacket Plus ensures that the best possible perfecting quality is achieved," he said.
"In comparison with traditional perfecting presses with up to six colours, the increase in productivity on the new CD 74 with a sheet reversing device is directly related to the job mix. The more often heavier printing stocks over 250gsm are utilized, the more the improvements in productivity become evident.
"The main reason for this is that these printing substrates, which were previously considered difficult, can now be produced with short set-up times, reduced cleaning times and an effortless production run.
"The CD 74 allows a pile height of 1.2 m in the feeder, and can even be raised by another 550mm which greatly reduces the number of interruptions caused by pile changes, especially for thick substrates like carton," Sommer said.