Why disappearing ink isn't just for spies
Published: 13 Nov 2007 16:46 GMT
According to Brinda Dalal, an anthropologist at Xerox's Palo Alto Research Center (PARC), of the 1,200 pages of printed information the average office worker prints per month, 44.5 percent are for daily use, such as assignments, drafts or emails.
The problem is that, in most offices, paper is commonly used as a medium of display rather than storage or transfer. Dalal discovered that 21 percent of black-and- white copier documents are returned to the recycling bin on the same day they are produced.
In most companies, documents are created and transferred between individuals digitally, and then stored either on central servers or personal computers. They are only printed out or copied when needed for meetings, editing and annotating, or reading away from a computer, all of which imply a fairly transient use for the printed document.
The result is, of course, an enormous quantity of waste paper, paper that is not only increasingly expensive to buy, but that involves the use of a considerable amount of natural resources, in particular energy.
It takes about 202,000 Joules to manufacture one sheet of virgin paper. Recycling that sheet takes a further 114,000 Joules. When you consider that, this year alone, about 2.5 trillion pages will be printed worldwide, it is clear that the production and recycling of paper represents an enormous amount of energy usage; not to mention the cutting down of a few forests.
Xerox transient paper technology
Xerox is just one of the companies investigating how to use paper more efficiently. The company believes the solution to this environmental problem is to reuse the paper.
Reusable paper is, of course, hardly a new idea. Medieval monks reused velum manuscripts by scraping off the top layer containing the ink from the original document to create a clean surface suitable for writing a new document — known as palimpsests.
The idea of scraping off the top layer to expose a clean new surface for writing has been adapted to paper. Right up until 2005 it was possible in the US to buy a reusable paper called Eaton's Corrasable Bond, which had a glazed surface that could be removed by friction.
However, such techniques are hardly suitable in an era of photocopiers and computer printers. In response to Brinda Dalal's research on paper usage in offices, the solution developed by Xerox's researchers at Palo Alto and Xerox Research Centre of Canada labs over the past three years is an office copier/printer system that creates paper-based transient documents where the printed information simply disappears within about 16 hours, allowing the paper to be reused.
When you consider that this year about 2.5 trillion pages will be printed, it is clear the production and recycling of paper represents an enormous amount of energy usage
"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. 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," says Paul Smith, manager of Xerox Canada Research Centre's new materials design and synthesis lab.
In fact, the self-erasing concept itself is not entirely new. In the 1990s, Japanese office-equipment maker Ricoh developed a commercial system that removed toner from paper in order to make it possible to recycle individual sheets up to 10 times. However, this system failed commercially and is no longer available.
In 2003 Toshiba also developed and marketed a system using a special blue, decolourable ink that disappeared when the paper was heated in a special eraser box. However, the high price of the erasing system and the paper and the toner, coupled with the time and effort required to erase documents has meant that this product has rarely been seen outside Japan.
Xerox has yet to make a decision to go to market with its technology. "This will remain a research project for some time," said Eric Shrader, Xerox 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."
However, the Xerox system's developers do believe that their technique solves most of the major commercial limitations that earlier developers such as Toshiba and Ricoh encountered. Its first advantage is that it requires no special eraser system — the print simply disappears after 16 hours. Second, no special toner...
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