Toshiba has developed a printer that re-writes over old paper, erasing and reusing a single sheet up to 500 times.

Billed as the world's first rewritable printer, the SX8R prints to special sheets made from PET, the same polymer used in the making of plastic bottles.

Because the sheets are instantly recycled, Toshiba claims it is an environmentally friendly printer. Michael Keane, head of Toshiba's European print division, told PCW this technique "conserves forests in a small way".

The printer is currently on sale in Japan, but is not ready for the UK yet because it needs power-modifications and ROHS compliance.

If Toshiba eventually does sell the printer in the UK, it will cost around £5,000. A further £2,700 will buy a separate cleaner to remove grease, dust and dirt from the paper to improve its longevity.

According to Toshiba's figures, a single sheet of re-writable paper would sell for about £5.40 in the UK, compared to up to 2p for a normal piece of paper. Toshiba's paper can only be printed on one side.

In Japan, Toshiba reckons the total cost of ownership to be $28,000 for the SX8R over a five-year period (including consumables and maintenance). It claims this is about $10,000 less than a standard laser printer.

The printer uses a thermal printing technique, similar to the one first used on fax machines in the 1980s and '90s. Part of the printer heats the entire sheet to 180ºC to erase any previous use, followed by reprinting with a 400ºC print head.

It prints at 12ppm (pages per minute), which is much slower than the 47ppm achieved by devices such as Dell's £600 top-end laser printer, which Toshiba considers its main compeititive type of printer.

Energy consumption is relatively low. It consumes 160W during continuous printing and 24W in power-saving mode. However, its slow speed will result in much higher energy usage compared with a standard laserjet since a page takes a lot longer to print.

Toshiba says the technology will never filter down to a consumer level.

See our video clip of it erasing and reprinting over a sheet of paper