Feeds

Cambridge boffins build laser 'unprinter' to burn pages clean

Works with standard paper and toners

Top three mobile application threats

A team of scientists from the University of Cambridge has published plans for a laser "unprinter", which vaporizes toner used in printing to leave a clean sheet of paper.

The idea of reusing printed paper has been around for a while, and it's not too difficult provided you use expensive coated paper. Toshiba has recently been showing off a printer that can erase its own single color toner off normal paper, but the technique has limitations. With Toshiba's system the ink is heated to make it disappear, but the technique leaves a residue and the same paper can only be reused five times.

"Toshiba have been selling the 'e-blue' toner for a while - which, like old thermal fax paper, fades under the right type of light. However that - of course - applies only if you buy their magic toner," the Cambridge project's supervisor Julian Allwood told New Scientist. "Our ambition was to develop a method that would remove conventional toner from conventional paper in order to allow re-use of the paper. Toshiba's is a different approach to the same problem."

The Cambridge team figures it has cracked the problem, and its unprinter can work with any laser printed or photocopied paper, with no need for special toner that's more expensive gram-for-gram than cocaine. It works by tracing the outline of the toner and then flash-frying it off using the device's laser.

"The key idea was to find a laser energy level that is high enough to ablate - or vaporise - the toner that at the same time is lower than the destruction threshold of the paper substrate. It turns out the best wavelength is 532 nanometres - that's green visible light - with a pulse length of 4 nanoseconds, which is quite long," said team member David Leal-Ayala.

The team used the technique to wipe a standard sheet of A4 three times without appreciable damage, but have warned that using the system too much could result in damage to the substrate, causing a yellowing effect. They have found some papers hardier than others, and are continuing experiments while considering whether to file patents or commercialize the technology. ®

High performance access to file storage

More from The Register

next story
KILLER SPONGES menacing California coastline
Surfers are safe, crustaceans less so
Opportunity selfie: Martian winds have given the spunky ol' rover a spring cleaning
Power levels up 70 per cent as the rover keeps on truckin'
LOHAN and the amazing technicolor spaceplane
Our Vulture 2 livery is wrapped, and it's les noix du mutt
Liftoff! SpaceX Falcon 9 lifts Dragon on third resupply mission to ISS
SpaceX snaps smartly into one-second launch window
KILLER ROBOTS, DNA TAMPERING and PEEPING CYBORGS: the future looks bright!
Americans optimistic about technology despite being afraid of EVERYTHING
R.I.P. LADEE: Probe smashes into lunar surface at 3,600mph
Swan dive signs off successful science mission
Discovery time for 200m WONDER MATERIALS shaved from 4 MILLENNIA... to 4 years
Alloy, Alloy: Boffins in speed-classification breakthrough
prev story

Whitepapers

SANS - Survey on application security programs
In this whitepaper learn about the state of application security programs and practices of 488 surveyed respondents, and discover how mature and effective these programs are.
Combat fraud and increase customer satisfaction
Based on their experience using HP ArcSight Enterprise Security Manager for IT security operations, Finansbank moved to HP ArcSight ESM for fraud management.
The benefits of software based PBX
Why you should break free from your proprietary PBX and how to leverage your existing server hardware.
Top three mobile application threats
Learn about three of the top mobile application security threats facing businesses today and recommendations on how to mitigate the risk.
3 Big data security analytics techniques
Applying these Big Data security analytics techniques can help you make your business safer by detecting attacks early, before significant damage is done.