Hybrid paper/display erases itself, cuts waste

30 Nov 2006

Another step on the road to "digital paper", Xerox’s new paper/display development results in temporary documents on reusable paper.

Xerox scientists have invented a way to make prints that last only a day, so that the paper can be used again and again. The technology, which is still in a preliminary stage, blurs the line between paper documents and digital displays and could ultimately lead to a significant reduction in paper use.

The experimental printing technology, a collaboration between the Xerox Research Centre of Canada and Xerox subsidiary PARC (Palo Alto Research Center), could replace printed pages that are used for just a brief time before being discarded. Xerox estimates that as many as 40% of pages printed in the office are for what it calls "daily" use, such as e-mails, web pages and reference materials that have been printed for just a single viewing.

"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," said Paul Smith, manager of XRCC's new materials design and synthesis lab.

Xerox has filed for patents on the technology, which it calls "erasable paper". It is currently part of a laboratory project that focuses on the concept of future dynamic documents.

To develop erasable paper, researchers needed to identify ways to create temporary images. The breakthrough came with the development of compounds that change color when they absorb a certain wavelength of light but then gradually disappear. In its present version, the paper self-erases in about 16-24 hours and can be used multiple times.

While scientists at XRCC work on the chemistry of the technology, their counterparts at PARC - the birthplace of the laser printer - are investigating ways to build a device that could write the image onto the special paper. PARC researchers developed a prototype "printer" that creates the image on the paper using a light bar that provides a specific wavelength of light as a writing source. The written image fades naturally over time or can be immediately erased by exposing it to heat.

While potential users have shown interest in transient documents, there is still much to be done if the technology is to be commercialized. "This will remain a research project for some time," said Eric Shrader, PARC area manager, industrial inkjet systems. "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."

Temporary documents are part of Xerox's ongoing investments in sustainable innovation - or "green products" - that deliver measurable benefits to the environment, such as solid ink printing technology, which generates 90 percent less waste than comparable laser printers; more energy-efficient printers, copiers and multifunction devices; and other paper-saving innovations.