Printer Ink Developers Fight 'Chunkies,' 'Froth'

Investor's Business Daily
Monday July 3, 7:00 pm ET
Ken Spencer Brown

No matter how advanced, print heads are useless without ink. And designing that ink is no small feat.

To accommodate scalable printing's design, Hewlett-Packard's 100 or so chemists had to formulate a set of inks, almost from scratch.

That was tougher than it might sound, says Jay Shields, research and development manager for HP's (NYSE:HPQ - News) consumer inks. "It's not just colored water," he said.

New inks typically go through a thousand iterations before HP settles on the final product. Moving to scalable printing has only complicated matters. (See related stories, A1 and this page.)

"They've spent a ton of money developing the inks for these things," said Jim Forrest, an analyst at Lyra Research, a printer-industry consulting firm. "It is rocket science."

First, the liquids have to fit through the new print-head nozzles and stick to paper, whether standard issue or specially coated photo paper for higher resolutions.

But those are challenges with any new print head. Scalable printing introduced several new issues.

The first: how to get the ink from the storage tank to the print heads.

Like most rivals, HP has traditionally sold ink cartridges with built-in print heads. The new printers use permanent print heads, located several inches away from the replaceable ink storage tank.

To get the ink from the tank to the head, scientists had to find the right material for a tube. It had to be flexible enough to move with the print head, but not too costly.

They found one. But the best plastic for the job presented a new problem -- it was slightly water soluble, letting out tiny amounts of evaporating water over time. That thickened the remaining ink, leading to clogs.

"If you have little chunkies floating around in there, bad things happen," Shields said.

Their next challenge: froth.

Most inkjets work by heating the ink to form a tiny bubble, which pushes liquid through the nozzles and onto the paper.

Every so often, the printers must get rid of the air that builds up. Usually this happens by venting the air -- along with several drops of precious ink. To cut down on waste, HP's system recycles the ejected ink back into the storage tank.

But like soapy dish water, early ink prototypes would foam up when stirred up in the recycling process, creating new problems.

"It's a little like cooking," Shields said. "It's part science and part art."

After getting past those issues, the inks faced another battery of tests.

In the basement of the ink building lies what amounts to an ink torture chamber. Called the environmental test chambers, a collection of sealed rooms simulates the harshest conditions of customers.

A room heated to 85 degrees Fahrenheit and moistened to 80% relative humidity acts as a stand-in for Brazil's tropical rain forest. Another room at the same temperature but on 20% humidity could be Arizona, or the Middle East.

Three buildings away, researchers try to accelerate time with heat and bright light to see how well their inks age. Under a barrage of concentrated light, ozone and humidity, a single day takes a year out of the life of a standard print.

Finally, in yet another test area, drop tests simulate rough shipping and clumsy users.

The process is a lot of work, one reason HP owns more than 4,000 patents on printer supplies, mostly on ink formulations. It has sued several ink makers in recent years over what it says is patent infringement.

More recently, it warned Office Depot (NYSE:ODP - News) and Staples (NasdaqNM:SPLS - News) that private-label inks sold at the office-supply retailers breach HP patents.