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Chemists unveil 'water-jet' printer, with ink that fades in a day

Published on Jan 29, 2014 12:41 AM

PARIS (AFP) - Like any ordinary printer, this machine ingests a blank page and spits it out covered in print. But instead of ink, it uses only water, and the used paper fades back to white within a day, enabling it to be reused.

A team of chemists claims their "water-jet" technology allows each page to be reprinted dozens of times - a money- and tree-saving option in a digital world that still relies heavily on hard copy.

"Several international statistics indicate that about 40 per cent of office prints (are) taken to the waste paper basket after a single reading," said Mr Sean Xiao-An Zhang, a chemistry professor at Jilin University in China, who oversaw work on the innovation.

The trick lies in the paper, which is treated with an invisible dye that colours when exposed to water, then disappears. The print fades away within about 22 hours at temperatures below 35 deg C as the water evaporates - quicker if exposed to high heat, Mr Zhang and a team wrote in a paper describing their invention in the journal Nature Communications.

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