Upcoming: A Handful Of Reverse Printing Technologies – ‘Un-print’ Content From Paper
With precise blasts of a green laser having length of four billionths of a second, the target paper can be easily made useable for re-printing content. This newly proposed technique is said to be 20 times more efficient than re-cycling. And that’s a lot of eco-friendliness on hand. But, this technology is still being perfected at the University of Cambridge, hence there is time until you can get your hands on the Un-Printer.
Toner-print removal from paper would allow paper to be re-used instead of being recycled, incinerated or disposed of in landfill. This could significantly reduce the environmental impact of paper production and use. Previous work on the subject has explored the applicability of ultraviolet, visible and infrared (IR) lasers under nanosecond pulses for toner removal. - An excerpt from the journal of The Royal Society
This is how reverse printing technology from the University of Cambridge works,
You should also note that Toshiba already has brought out a similar product that uses a ‘special toner’ to print content on any regular paper and erase them conveniently. So with this, only content printed with a ‘special ink’ can be un-printed.