Un Printer

Laser UnPrinter wipes photocopied ink from paper

refer:

bbc unprinter

Abstract

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. This article expands on this work by testing a wider range of ultrafast and long-pulsed lasers. Results from 10 distinct laser set-ups are used to propose an operating window for the toner-removal process. Colour analysis under theL*a*b* colour space, scanning electron microscope examination and attenuated total reflectance–Fourier transform IR spectroscopy measurements of the outcome show that, with the right laser, it is possible to remove toner from paper to enable its re-use. Theoretical models to predict the laser ablation of toner are discussed, and, while imperfect, provide sufficient evidence to support a physical explanation of toner ablation.

Researchers at the University of Cambridge have developed what they call a laser ‘unprinter’ – a device that is able to remove toner ink from paper. A production model would allow businesses to reuse copier paper rather than sending it off for recycling, a process that is good for the environment but admittedly uses a lot of resources in the process.

The procedure works by firing green laser pulses in four billionths of a second increments at the ink. The laser effectively vaporizes the plastic polymer found in toner, leaving only a small trace of the ink behind. A ventilation system was used to remove nanoparticles and mostly harmless gases produced during the procedure.

Bending, curling and accelerated-aging tests on the ‘unprinted’ paper show no long-term signs of damage and was comparable to a regular piece of paper.

This isn’t the first time that someone has developed a device to remove ink from paper, but this latest ‘unprinter’ does so without some of the restrictions that other devices bring to the table. Toshiba currently offers a laser printer that offers a similar function but users must utilize a special ‘e-blue’ ink when printing, effectively limiting its useful scope. Other methods tend to damange the paper or leave it discolored.

The researchers are now planning to build a prototype device which they suspect can be done for around $25,000. This price would likely fall by a large margin should the 'unprinter' find its way into production at a later stage.