Chasing the Holy Grail of Inkjet Printing

Episode 1: Where Ink and Paper Meet

By Noel Ward, Editor@Large

It’s probably no coincidence that adoption of high-speed inkjet printing has been growing right along with the throughput speeds of the presses. But for all they offer, high-speed inkjet systems have typically lacked the ability to handle coated or glossy substrates. Now, thanks to changes in inks and papers, such stocks are speeding beneath the print heads of many inkjet presses. This expands the opportunities for print providers but not without some challenges.

Challenges
The first one comes as the ink hits the paper. While glossy or coated surfaces can enhance the visual “pop” of text and images on printed image, their “harder” surface resists ink penetration, limiting dot gain and the extent to which colors can merge. This can impact image quality because unlike offset presses, inkjet systems rely on some ink absorption into the outer layers of paper.

The next challenge is related: lack of absorption also causes drying problems because ink droplets sits on top of the substrate. Inks that aren’t compatible with the surface chemistry of the paper may not dry correctly or can scrap or chip off, so the ink must be dried before finishing takes place. Of course, this is not unique to inkjet presses. Offset prints can seem dry or nearly dry immediately after printing, but most printers still allow offset pages on coated or glossy stocks to dry for a day or two before any finishing takes place.

The difficulty for inkjet press and paper vendors, as well as print providers, is getting around this ink and paper problem so that high-speed inkjet presses can be true alternatives to offset presses. In finding the way around two choices have evolved. First, paper companies—in conjunction with press makers—are developing papers with surface chemistries compatible with inkjet inks. Second, some press makers have ways of treating glossy or coated papers with a “priming fluid” that helps them reliably accept inkjet inks. Of course, these strategies must work at the 400 to 800 feet-per-minute speeds of inkjet presses while ensuring the inks dry without smearing, smudging or offsetting during rewinding or finishing.

That all sounds great and is a bit of vendor-speak at the 30,000 foot view. But what is really happening?

The word on the ground
To find out I talked with or visited executives in companies that operate of some of the leading inkjet presses available today, including the Canon i300, HP T-Series, Konica Minolta KM-1, Fuji J-Press, Ricoh VC Pro 60000, Screen 520HD, and Xerox Trivor. The companies were these machine reside run applications ranging from direct mail to publishing to commercial printing, providing customers with offset, toner and inkjet printing, based on application, run length and customer need. The people I spoke with have all been commercial printers for at least a couple of decades and they emphasized one thing: successful print providers must provide toner, inkjet and offset printing if they are to retain business that might otherwise go to a competitor or get a bigger share of a customer’s wallet. In other words, you better have a full range of print technology if you are going to be competitive.

Glossy papers change the game
All the printers I talked with agreed that printing on coated or glossy stocks adds a new dimension to inkjet printing, making it more attractive for some applications. Lead among these is direct mail (DM).

For example, one company does a lot of DM work with auto manufacturers. “Glossy stocks make the cars and trucks look much better, which is part of brand identity,” says a Canon i300 owner. “The targeted variable content we add increases the value of the mail piece, but we still need the glossy stock to provide the look and feel our customers want.”

Another, a Ricoh VC Pro 60000 owner, produces a variety of direct mail materials that go to frequent casino patrons. “These have to be on coated stocks because casinos want the ‘bling’ that a glossy or coated stock provides,” he explains. “Our ability to print variable content, use a glossy stock, and turn the jobs quickly makes inkjet the best process.”

Before their inkjet machines arrived both firms preprinted shells on their offset presses and added variable content using monochrome laser printers. Short runs would sometimes be completely printed on a high-end toner press, but customers said the per-piece cost was too high. Now, inkjet presses running glossy or coated stocks are delivering the desired print quality while decreasing cost.

One of print execs I talked with had been on a panel I ran at a conference a few years back. He runs an entirely digital facility that is part of a company that provides all print technologies over multiple locations. His facility prints full-color books and booklets for healthcare and financial services companies, as well as targeted inserts for a variety of publications. Many of these jobs require coated or glossy stocks and are nearly all run on HP T-Series inkjet presses. He noted that the only exceptions are for documents with very high ink coverage, in which case the work is run on a toner press. This prompted me to ask other execs about this and I found that virtually all high ink coverage jobs tend to wind up on toner presses. It comes down to using the best tool for the job.

Running HP T-Series presses, the shop primarily uses various grades from Appleton Papers that are designed for those machines. The company turns to HP’s “bonding agent” for papers not approved (by HP) for the T-Series machines, including some coated stocks, and has not yet migrated to HP’s High Definition Nozzle Architecture (HDNA) which is said to deliver higher quality half-tones, color fills and smoother transitions. The shop also hasn’t made the leap to a “priming fluid” specifically intended for glossy papers.

Coming next week:
Episode 2: To Prime or not to Prime? Print providers consider the value of priming fluids to improve ink adhesion on glossy stocks.
 

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