Hey, where did that document go?

Because many e-mails and documents are printed out for brief viewing and then soon discarded or recycled, Xerox invented printing technology that creates images that last only a day.

The technology, dubbed Erasable Paper, could lead to a significant reduction in the amount of paper used in an office, because once the image fades away, the paper can be used over and over.

"Despite our reliance on computers to share and process information, there is still a strong dependence on the printed page for reading and absorbing content," said Paul Smith, a Xerox manager, in a written statement. "Of course, we'd all like to use less paper, but we know from talking with customers that many people still prefer to work with information on paper. Self-erasing documents for short-term use offers the best of both worlds."

Xerox estimates that two out of every five pages printed in an office are for one-day use, such as e-mails or reference materials that only are needed for a single viewing.

The company noted that it has filed patents on the Erasable Paper technology.

The experimental printing technology came out of a collaboration between the Xerox Research Centre of Canada and the Palo Alto Research Center. According to an online release, the "aha" moment came for Xerox researchers when they developed compounds that change color when they absorb a certain wavelength of light but then will gradually disappear. As it stands now, the paper erases itself in a 16- to 24-hour range. The paper then can be reused.

Researchers at the Xerox Research Centre are working on the ink part of the equation, while scientists at PARC are working on building a machine that can print the image onto the special paper. They are developing a prototype printer, according to Xerox, that creates the image using a light bar that provides a special wavelength of light as the writing source.

"This will remain a research project for some time," said Eric Shrader, PARC area manager of industrial inkjet systems, in a written statement. "Our experiments prove that it can be done, and that is the first step, but not the only one, to developing a system that is commercially viable."