A new way to unprint paper using intense pulsed light from a xenon lamp. Source: Rajiv Malhotra/Rutgers University-New BrunswickA team of Rutgers University-led researchers has devised a new method for "unprinting" standard coated paper.

To unprint the paper, the Rutger’s team subjected it to intense pulses of light from a xenon lamp and a swipe of benign alcohol. The combined steps resulted in the removal of black, blue, red and green toners without damaging the paper. Although other laser-based methods for unprinting paper already exist, the Rutger’s method reportedly works with standard coated paper, the kind used in home and office printers.

Traditional coated paper recycling is a significant contributor to climate change emissions, energy use and chemical pollution, so the Rutger’s team believes that their new unprinting method will prolong the life of paper, potentially avoiding recycling and yielding environmental benefits.

"Our method makes it possible to unprint and then reprint on the same paper at least five times, which is typically as many times paper can be reused with conventional recycling. By eliminating the steps involved in conventional recycling, our unprinting method could reduce energy costs, pollution and greenhouse gas emissions," said study co-author Rajiv Malhotra, an assistant professor in the Department of Mechanical and Aerospace Engineering in the School of Engineering at Rutgers University-New Brunswick.

The Rutgers-led team will further refine their technique by testing it with additional toner colors and on a larger selection of paper types.

The research is published in the Journal of Cleaner Production.