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Researchers Use Lasers to Un-Print Printed Paper

Removing printed toner on paper, similar to how we use an eraser to clear pencil writing, is not something entirely new, but there has never been a feasible approach for the mass market.

However, researchers at the University of Cambridge now claim that ultrafast and long-pulsed lasers can be used to save printed paper from the trash bin and prepare it for reuse.

According to a paper published in Proceedings Of The Royal Society A, a 532 nm green laser light with a pulse length of 4 nanoseconds can evaporate printed toner from paper without significantly damaging it. The process works two to three times before damage would become apparent via a slight yellow tint of the paper, the scientists said. They do not claim that the process is perfect, but they believe that they are on a promising path to enable an un-printer at some point.

According to a press release released by the University of Cambridge, the print removal would be much more environmentally friendly than recycling and producing new paper. Compared to recycling, the un-printing process would save an estimated 50 to 80 percent of carbon emissions.

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  • 15 Hide
    arvalin_dakaria , March 16, 2012 2:24 AM
    But would it be cost effective?
  • 14 Hide
    keyanf , March 16, 2012 2:32 AM
    Something tells me fixing the print code so you don't wind up with various pages with 1 line each in the first place is more cost efficient...
Other Comments
  • 15 Hide
    arvalin_dakaria , March 16, 2012 2:24 AM
    But would it be cost effective?
  • 14 Hide
    keyanf , March 16, 2012 2:32 AM
    Something tells me fixing the print code so you don't wind up with various pages with 1 line each in the first place is more cost efficient...
  • 3 Hide
    mcd023 , March 16, 2012 2:40 AM
    if you have an office that prints and disposes tons of paper, it'd be effective. just be sure not to get them crumpled! how many new paper jams would that cause?
  • 3 Hide
    Marco925 , March 16, 2012 2:56 AM
    so now the printer manufacturers have a new product to charge next to nothing for, but make us replace the laser every few weeks for $1000 a pop
  • 2 Hide
    nebun , March 16, 2012 3:18 AM
    arvalin_dakariaBut would it be cost effective?

    most likely NO
  • 8 Hide
    GenericUser , March 16, 2012 3:22 AM
    It would be really cool if it could somehow store the evaporated toner for re-use.
  • 0 Hide
    livebriand , March 16, 2012 3:26 AM
    Marco925so now the printer manufacturers have a new product to charge next to nothing for, but make us replace the laser every few weeks for $1000 a pop

    lol... right now, my printer claims some of the toner cartridges are low. When it actually decides they're empty, I'll be using a little trick to force it to use it anyway. lol... printer manufacturers love to charge you too much for things...
  • 3 Hide
    Benihana , March 16, 2012 3:42 AM
    livebriandlol... right now, my printer claims some of the toner cartridges are low. When it actually decides they're empty, I'll be using a little trick to force it to use it anyway. lol... printer manufacturers love to charge you too much for things...

    Oh Brother! I hear you on that! :p 
  • 9 Hide
    Genny , March 16, 2012 3:44 AM
    It's far better suited for destroying confidential documents than any sort of 'green initiative'--erase ink then shred. I can see it serving a purpose.
  • -1 Hide
    joytech22 , March 16, 2012 4:45 AM
    GennyIt's far better suited for destroying confidential documents than any sort of 'green initiative'--erase ink then shred. I can see it serving a purpose.


    I'm sure that since it damages the paper in a way, they could just find out what the original content was anyway but the smarter thing to do would be to "erase" it with the un-printer and shred it both ways.
  • 1 Hide
    Alsone , March 16, 2012 8:28 AM
    What about lung disease though?

    I thought toner particles were long thought bad for the lungs and yet this process sounds as though its atomising them off the paper through using the laser. Surely that will be hazardous to office workers.
  • 0 Hide
    JOSHSKORN , March 16, 2012 8:38 AM
    keyanfSomething tells me fixing the print code so you don't wind up with various pages with 1 line each in the first place is more cost efficient...

    Ha I remember my first Visual Basic class, creating a report...I screwed up in that very manner.
  • 0 Hide
    Anonymous , March 16, 2012 8:55 AM
    Make it solar powered and you got a deal!
  • 0 Hide
    neon871 , March 16, 2012 10:20 AM
    Researchers on AMP Energy drink............!
  • 1 Hide
    cookoy , March 16, 2012 10:30 AM
    How much power would be needed to power up the laser to wipe clean a standard letter-size or A4 sheet of paper? Will the toners be totally evaporated without leaving residues?
  • 0 Hide
    back_by_demand , March 16, 2012 11:37 AM
    Eventually this will be incorporated into all standard laser printers, then we can print, erase and re-use most standard printouts
    ...
    This will never be used for confidential documents, however
  • 0 Hide
    leo2kp , March 16, 2012 12:18 PM
    I can't see this being widely adopted. Much of what is printed contains private data, which would probably be recoverable when erased.
  • 1 Hide
    rantoc , March 16, 2012 12:54 PM
    Considering its paper i have a feeling the paper jams costs when printing on used paper will outweigh the gains...
  • 0 Hide
    __-_-_-__ , March 16, 2012 1:52 PM
    arvalin_dakariaBut would it be cost effective?

    no. Because:
    the price of removing the toner is bigger then recycling it even considering the environmental cost.
  • 0 Hide
    gallidorn , March 16, 2012 2:17 PM
    I'm sure when this technology becomes available, someone will figure out how to remove specific sections of print and then check cashing fraud will increase substantially!
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