Feeds

Cambridge boffins build laser 'unprinter' to burn pages clean

Works with standard paper and toners

5 things you didn’t know about cloud backup

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. ®

Secure remote control for conventional and virtual desktops

More from The Register

next story
Boffins attempt to prove the UNIVERSE IS JUST A HOLOGRAM
Is this the real life? Is this just fantasy?
Our LOHAN spaceplane ballocket Kickstarter climbs through £8000
Through 25 per cent but more is needed: Get your UNIQUE rewards!
Software bug caught Galileo sats in landslide, no escape from reality
Life had just begun, code error means Russia's gone and thrown it all away
LOHAN tunes into ultra long range radio
And verily, Vultures shall speak status unto distant receivers
SpaceX prototype rocket EXPLODES over Texas. 'Tricky' biz, says Elon Musk
No injuries or near injuries. Flight stayed in designated area
Galileo, Galileo! Galileo, Galileo! Galileo fit to go. Magnifico
I'm just a poor boy, nobody loves me. But at least I can find my way with ESA GPS by 2017
EOS, Lockheed to track space junk from Oz
WA facility gets laser-eyes out of the fog
prev story

Whitepapers

Gartner critical capabilities for enterprise endpoint backup
Learn why inSync received the highest overall rating from Druva and is the top choice for the mobile workforce.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Rethinking backup and recovery in the modern data center
Combining intelligence, operational analytics, and automation to enable efficient, data-driven IT organizations using the HP ABR approach.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
Next gen security for virtualised datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.