Naumenko A.Yu. , Kostiv V.K.

Oles Honchar Dnipropetrovsk National University, Ukraine

TECHNOLOGY OF REMOVAL OF TONER FROM THE PAPER

By the scientists at Cambridge University (UK) there has been developed a laser technology to completely remove from the sheet printed on it text, without damaging the paper, which can then be used again and again to print.

The project was worked out by a group of scientists led by Dr Julian Allwood head of laboratory at Cambridge University, engaged in research of the field on materials processing.

It is known that earlier, Toshiba has already presented a special toner that is removed from the sheet of the paper after it is heated. At the heart of their idea is the same technology as in erasable pens FriXion Ball – in both cases, the ink loses its color due to exposure to heat. In the case of handles, the heat is due to friction, and in the printer – with the help of a heating element.

Developing is a system of two modules: one module – a printer that works just like any other, except that it uses erasable toner. To clear the sheet, it must be put into the second device, which discolors the toner. The output of the paper looks almost like new.

At the same time the module of removing the toner is able to determine how many times the page was used, and automatically rejects-unsuitable for erasing the sheets into a separate tray. The device has an option allowing to scan a document before erasing and store it in digital format.

The demo version of the new system prints in blue, but, according to the words of representatives of Toshiba, the company is already working on other colors. New product should be in stores by the end of this year.

Developers use the Toshiba toner and a heating element, wherein a particular composition. It is worth emphasizing that the toner is compatible only with specific printers. In fact, with the help of technology printing characters are faded, but not erased completely. Therefore, printing of confidential documents should be carried out by using traditional printing systems.

However, their technique requires special ink cartridge, and the technology developed by scientists from Cambridge allows to remove the toner plain paper.

Having studied about ten laser systems with different power and pulse length, the researchers from Cambridge stayed in the green laser with a pulse of a few nanoseconds – the optimum wavelength is 532 nm, and the frequency of pulsation – 4 ns.

This laser can heat up certain parts of the paper, and under the influence of temperature toner evaporates. The beam of the laser passes through the cellulose fibers in the paper and it does not cause any harm. At the same time,the scientists were convinced, after examining the paper under a microscope, and carrying out an analysis of the color characteristics, mechanical and chemical analysis.

Earlier Allwood and Lil-Ayala showed that treatment with a special sandpaper can remove the toner. "It works, but you cannot avoid of thinning of the paper, so that the number of applications of this technology with respect to one sheet is limited," says Allwood. But the use of laser light avoids this problem.

The technology allows to print / erase the text a few times, but a few such cycles lead to the fact that the paper starts to turn yellow and eventually becomes unfit to print. In their paper, the researchers performed three times in the cycle printing / erasing, and in all cases there were high-quality results.

Now researchers have created only a laboratory setting, which is intended to be improve and reduce by them to the size of an ordinary printer, which can be used in offices. As for the cost of such an anti-printer, then, according to scientists, it will be about 30,000 dollars (about 19,000 pounds), but if the production does begin, it is possible that the cost will decrease.

The invention is not patented by scientists yet and, accordingly, to say about leading it up to the international market is too early.

According to experts, the use of the technology developed will harmful halve emissions into the atmosphere from manufacturing and recycling of paper. A pair of researchers has shown that the new method in the worst case be reduced by 50 per cent of carbon emissions into the atmosphere in the processing of paper, and, at best, to reduce harmful emissions by about 80 percent. It is also noted that the evaporation does not affect the health and completely harmless.

There is already a huge industry, companies of which are engaged in removing the ink from the paper. This is a part of the process of refining precious resource. The process of removing the toner is used to improve the quality of cellulosic material in the recycled paper. But the possibility of removing paint without processing gives a great advantage, as less perfect technologies involve the use of huge amounts of energy and resources, especially water.

It is worth noting that currently in the web, there are suggestions that this technology can be used in fraudulent schemes, particularly in forging documents.

In English-speaking tech blogs there have already been noted comments that the technology can be equally used for forgery.