A Chinese company has developed a breakthrough recycling technology which can remove ink from a printed sheet and allow both paper and inks to be reused.
The laser system used by Lucky Unicorn Company is used to remove each ink in turn; black, cyan, magenta and yellow, regardless of the sequence they were laid down in. In the core patent, which the company applied for on 1 April 2018, it describes what it calls the ink lifting process. It can be found as patent no 32560104, or “0104” for convenience. This describes how a water based coating is applied to the printed sheet to loosen the chemical bonds that join ink to ink and ink to paper.
A laser, tuned to the specific light wavelengths of each colour, completes the process. The wavelength of the laser energy excites the pigment molecules in the ink encouraging them to break away from the paper and allow then to be removed from the sheet.
The “0104” patent describes how the ink is captured from the sheet by a scavenger roller to move ink to a reservoir, to be returned to the supplier. Each colour is removed in turn, leaving an ink-free sheet at the end of the process. The ink can then be sold back to the original ink producer and reused as litho ink or toner.
“The process has tremendous advantages over the conventional way to recycle paper,” says Fuld Yu, CTO of Lucky Unicorn. “That uses chemicals and water and a lot of energy. Our process is both fast and clean.”
The official launch takes place today in Shanghai as part of the high tech Forward On One Leap event. Invited delegates include representatives from the paper industry, and both litho and digital press suppliers. Lucky Unicorn is not intending to build its own press, but will licence the technology to recycling businesses and the press manufacturers who will be needed to commercialise the breakthrough. Yu says that early stage talks have gone well. “If they can include the LED laser that is needed into its conventional or digital press, and there is no reasons why they should not, the rest is simple.”
He says it will even be possible to reconfigure an existing litho or digital press, not to print ink on paper, but to remove ink from paper. The printed sheets will be fed through the delivery into a coating unit and then past a laser writing head mounted above the de-impression cylinder. Finally the clean sheet will be fed to the delivery. It will necessarily be smaller that the sheet that started the print journey, but can still have many commercial uses.
So far the technology has been equally effective on all types of paper, provided that sheets can be cleared of stitch wire or adhesive. A beta machine has been built around a Heidelberg litho and into Xerox digital press. Such a product would boost demand for the press manufacturers as for every printing press sold, there will be demand for an unprinting press.
The Xerox Palo Alto research facility has a long track record of breakthrough developments of its own and is understood to have been helping the Chinese developer with refining the “0104” patent with a launch planned for a year's time.
By Gareth Ward
Chinese inventors have come up with a way to remove the ink from a printed sheet using lasers tuned to the sonic frequency of the four colour print process. At a later stage, the developers expect to be able to strip away PMS colours as well as four-colour process in the unprinting process.