Piece of (Sheet) Cake
Press developments make the dizzying heights of today's sheetfed offset a little easier to reach.
by Jessica Millward, Associate Editor
IT WAS ALMOST heartbreaking for the packagePrinting 2000 Excellence Awards Competition judges. Faced with about 50 sheetfed offset folding carton entries, they struggled to whittle the category down to only four winners; ultimately, only the slightest register flaws eliminated the competition. Such a resounding testament to the health of sheetfed offset prompts a question: What challenges do sheetfed printers face? And what solutions do press suppliers offer to enable those formidable folding cartons?
Challenge 1: Freedom of substrate
Four years ago, Hammer Lithograph ran nothing but paper at its plant in Rochester, NY. Customer and marketplace demands encouraged the company to branch out, says Director of Sales and Marketing Louis Iovoli, into the realm of BOPP. Though once considered a sheetfed no-man's land due to the substantial drying time required for inks, Hammer now prints sheetfed BOPP on all its Mitsubishi presses, including a 56˝ model and an in-line UV press. Using a proprietary formula for controlling press variables, Hammer uses sheetfed BOPP for high-profile jobs such as the Perrier wide-mouth water labels.
Mitsubishi's Ray Mullen, VP, sales and customer service, sheetfed presses, notes the company's carton presses employ a heavy-duty sheet guide system to prevent marking or smearing of board, and the Centralized Operator MakeReady and Control (COMRAC) console handles adjustments for stock thicknesses and sizes in about one-third the normal makeready time.
To ascertain the substrate is running correctly, and to statistically define mechanical characteristics of the press, Mitsubishi recently premiered the third generation of its DRA (Digital Register Analysis) service. DRA 2000, provided to press buyers and existing users, measures, within microns, precise sheet-to-sheet movement on every element of the press, then determines standard deviation and the adjustments necessary to eliminate imperfections.
Challenge 2: Ink/water balance
Though you wouldn't know it from the multitude of awards the company has garnered, Bert-Co Graphics does come up against its share of printing difficulties. President Chuck Stay maintains, "It's not just ink we're trying to control, it's also water."
That delicate dampening balance is achieved on Bert-Co's new MAN Roland 900 through a combination of press components. A sophisticated inking unit, providing fast reaction and stable ink feed, is paired with the Roland Deltamatic dampener, which removes hickeys from the plate.
Mitsubishi, too, has focused on the water-ink issue, resulting in the Delta Dampening system, which maintains uniform application of dampening solution throughout the press run.
Challenge 3: Integration for automation
As a major player in the beverage carton converting market, Riverwood International is always on the lookout for shorter makeready. Its Clinton, MO, shop, the second largest of five North American facilities, recently replaced two older presses with a seven-color KBA Rapida 142 for exactly that reason.
With maximum speeds running to 14,000 sph, and a fully automatic plate changing ability, Jamie Huller, Riverwood's plant manager in Clinton, predicts a sizable cut-down in press downtime. Additionally, while the plant does not yet utilize a CTP system, Huller affirms Riverwood's intention to be prepared for the future, and therefore appreciates the Rapida's CIP3 compatibility.
KBA's Director of Marketing Bob McKinney counts increased productivity as the chief concern for most printers KBA services: "To that end we have automated nearly every labor-intensive function of the makeready process, including auto blanket and roller wash; automatic size and pressure setting; automatic ink key settings; as well as a closed-loop densitometry or spectrophotometry monitoring system. The productivity increase through this automation is a compelling economic argument for upgrading equipment."
Komori America's presses, historically developed with a sharp eye on automation and integration, feature the Digital Open Architecture network (DoNet) to accomplish total color management and process control. The newest member of the Lithrone family, the Lithrone 20, uses its LCD screen to set and adjust ink/water levels, adjust ink/water ramping speeds, and to establish register on the run, including lateral and circumference register moves as well as transfer cylinder cocking.
"Integration is the future," Heidelberg declared as its mantra for Drupa 2000. Detlef Janke, marketing director for the Speedmaster 102, adds, "That seems to be the key task for the industry: To integrate the entire production into a digital workflow and an automated material flow." In that vein, Heidelberg's new CP 2000 control center directs digital data, communicated via the prepress interface, directly to the press.
Heidelberg also recognized a vital element of the carton production process that would benefit from automation: the role of the feeder man. To cut down on extreme physical labor, Heidelberg developed the Logistics automated material system for Speedmaster presses. It consists of an automated roller conveyor mechanism to move pallets, and a stacking rake at the feeder to remove pile change from the human workload.
