Thursday, November 13, 2008

Xerox Invents Reusable Paper that Uses UV Light for "Ink"


Xerox subsidiary Palo Alto Research Center (PARC) has developed a type of paper that, combined with a special printer, can print documents that erase themselves after a day so that the paper can be reused.

Xerox says that 25 percent of all documents get recycled the same day they are printed, and that 44.5 percent are intended only for a single viewing. Using the new printer and paper for one-shot documents like daily menus, work summaries and office memos could vastly reduce paper and energy use, the company said.

"Think of the Google map you printed to get here," PARC Area Manager Eric Shrader said at a product demonstration. "Thirty years ago, we said the future was paperless."

"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, manager of Xerox's new materials design and synthesis lab.

The new paper is coated with a chemical that turns dark upon exposure to ultraviolet (UV) radiation. In order to create a document, the printer simply bombards the paper with UV radiation in the appropriate places.

While the "ink" will eventually fade on its own, after 16 to 24 hours, the printer can also be used to erase a page and print something new. Tests by Xerox found that if it was not torn or crumpled, a single piece of paper could be put through the print-and-erase cycle hundreds of times.

According to Shrader, it takes 204,000 joules of energy to create a new piece of paper and 114,000 to recycle one. Printing onto a normal sheet of paper uses about 2,000 joules.

It takes only 100 joules to print one page of the special erasable paper. If the printer also has to erase the prior image, printing uses about 1,000 joules of energy.

The erasable paper and ink are available in a variety of colors. Xerox expects to take the new product commercial within the next few years.

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