Talking newspapers: It's all in the ink

By Peter Svensson
Associated Press

Items featuring T-Ink technology were on display at this summer's Licensing 2003 International Show in New York. T-Ink is pioneering the use of electrically conducive ink in ordinary printing presses. Associated Press

Don't worry. This isn't about getting a shock off a printed page. Rather, it's about making electronics cheaper — at a fraction of a cent — by replacing wires, circuit boards and batteries with ink.

A small, New York-based outfit called T-Ink Inc. is pioneering the use of electrically conductive ink in ordinary printing presses.

"Our goal is a total print medium where your paper is going to talk," says Andrew Ferber, vice chairman at T-Ink and one of the brains behind the technology. He envisions newspapers that include printed loudspeakers, batteries and circuits.

For now, the technology is available in limited form and in somewhat trivial applications.

Conductive ink was used to print circuits on tray mats for Australian McDonald's. A light on a toy that came with meals lit up if it followed a mazelike circuit on the mat.

Also out from T-Ink is an inflatable radio with printed controls as well as a Clue game board that senses where the pieces are and plays sound effects — such as the sound of feet on gravel for someone near the stables.

Among other projects being considered: diapers with built-in wetness sensors, drug packaging for the elderly that reads the prescription aloud when touched, light switches painted onto walls and clear security sensors painted onto windows.

The company is starting much of its early efforts on toys and promotions — "you might call them the low-hanging fruit for us," Ferber says.

T-Ink's use of conductive inks is innovative, but the basic idea isn't new. Engineers use pens with silver ink to improvise or repair circuits on circuit boards, for instance. And underneath the keys of computer keyboards are membranes with printed circuits that sense when a key is pressed. Windshield defrosters are also printed.

But those applications are mostly screen-printed, a slow and expensive process used because it leaves a thick layer of ink, much like the ink on an embossed business card. With new inks, offset printing and other faster technologies can be used as well.

Ferber is coy about the composition of the inks, but says T-Ink has moved beyond the materials used to make traditional conductive ink — particles of silver and carbon. T-Ink's patent applications describe using various mineral powders and some conductive plastics. The inks can come in any color, and can be washable, too.

For all of Ferber's enthusiasm, conductive inks have drawbacks. Blue Ramsey, a researcher at Brunel University in England, has studied high-speed printing and points out that for one, conductive ink has more resistance than the copper used in traditional circuit boards. That means it can't carry a strong current efficiently.

Also, ink isn't very practical for making circuits that can do something smart, like performing a calculation. It isn't yet possible to print circuits that are as dense as those in a silicon chip, so a printed calculator would have to be huge, probably several square feet.