When Heat Hits Paper

A versatile sheet is key these days, with so many print firms printing both conventionally (offset) and digitally for shortrun jobs. But what does versatile mean today? And how do printers choose the optimal paper for a given job to be run on a digital press?

Of course, digital line expansion is nothing new. Mohawk Paper was one of the first mills to offer 8.5x11" and 12x18" cut-sheet sized paper for digital presses way back in 1996. We asked Joe Schember, specialty digital product manager at Mohawk, for his advice. “What has changed in the past 20 years,” says Schember, “is printing technology.

Now there are more sophisticated presses that can print on linen or felt, for example,” he points out. Demand has increased substantially as the quality of these digital press images now can legitimately compete with traditional offset.

Some common problems to beware of in the digital realm, according to Schember:

• Static issues
• Image quality issues
• Curling
• Paper cut in the wrong direction
• Excess paper dust
• Dull blades

Trends
Textured paper increases response rates, as myriad research has proven, Schember notes. “And opaque paper yields better quality in photo products,” he adds. “Customers are willing to pay a premium for these sheets because they really do deliver superior quality.”

Both paper mills and original equipment manufacturers (OEMs) are busy engineering coatings for coated sheets. Citing one example, Schember explains that Mohawk has developed in-house coatings for specific manufacturers. “Our engineers have developed chemistry that allows dry toner to adhere better to paper,” he says. In the packaging production space, he adds, “thicker, stiffer paper for ‘board’-type applications is in demand,” as are metallic and pearlized sheets.

Precision Sheeting
For digital machines, 80# text and cover weights are standard. OEMs such as Canon, HP, and Kodak feature structured, third-party media certification programs. (One is run out of the Print Lab at Rochester Institute of Technology [RIT].) Canon is in the process of revamping its testing program, which will run in conjunction with the development of new ink sets.

Beyond the legalities of non-disclosure agreements (NDAs), which are often required for product development and research and development (R&D) purposes, Mohawk’s Schember says that all digital press OEMs are looking for primarily the same performance characteristics when it comes to ink and paper:

• Ink adhesion
• No cracking when folded
• Minimal jamming
• Minimal build-up on press

Like any economics equation, paper buying all comes down to supply and demand. If you buy enough of it (5,000-lb. weight minimum), Mohawk will make any sheet in minimal sizes. A few mills offer 13x30" sheets for banners, dust jackets and panoramic prints. HP developed 20x29" sheets for its Indigo 10000 and 20000 models.

Situated in upstate New York, the 80-year-old Mohawk mill is well known for its premium and finer text and cover sheets. Schember offers sound advice when choosing paper for a printing project: “Ask yourself, ‘What should the finished piece represent?’ The answer will determine the paper you select, depending on whether it’s for a direct mail piece, marketing collateral, photobook, packaging, or synthetic applications.” For print firms doing the paper buying, “You can go from good to great [by] using different materials,” he recommends. “Be different; offer alternatives.”

The diversity of sheeted papers for digital press output has evolved with print tech over the past two decades, with sophisticated devices reproducing on textured and specialty media. What has not changed, however, is the bottom line, which still is superior image quality in most cases. For digital papers, improved adhesion has come by way of highly engineered coatings and inks developed by both paper mills and OEMs. Whichever paper your firm chooses, ensure that the sheets are versatile enough to deal with production issues such as static, curling, wrong grains, dust, and dull blades. Solving these problems will keep your crew – and your customers – happy in the end.