Xerox melts ink to stay green

PALO ALTO, Calif.--It looks and feels like a square, yellow crayon.

But it's actually a lot more sophisticated than that. It's ink in solid form (aptly called "solid ink") made of a polymeric resin, and Xerox researchers are using it, combined with advances in print head technology to make a greener printer.

Solid ink before it is melted and jetted onto paper in a printer.

(Credit: Erica Ogg/CNET News.com)

Solid ink is different from what's used in the average desktop printer. Instead of buying cartridges filled with liquid ink, which are inserted into small print heads that race back and forth to transfer an image to paper, solid ink is melted, then dripped into a single drum that's as wide as a regular sheet of paper.

The image is then transferred with heat and pressure to paper. It takes about 10 revolutions of the drum to transfer the image, which is then hardened and ejected from the printer.

So how is it greener? Liquid ink requires a lot more packaging--the cartridge and the box it comes in. Xerox says solid ink outputs 90 percent less waste than liquid ink, and saves up to 260 pounds of discarded cartridges and their packaging over the life of a single desktop printer.

It also doesn't require any water or solvent to dry the ink. It does, however, require more energy to heat thick ink to melt it. (The melting point is between 70 degrees and 100 degrees Celsius.) Xerox says it continues to tinker with insulation and the ink's melting point to squeeze more energy efficiency out of every solid ink printer.

Another way researchers are looking to improve the tech's green cred is through the print heads themselves.

Smaller, modular print heads distribute melted solid ink.

(Credit: Erica Ogg/CNET News.com)

By making the print head smaller than the standard 8.5-inch-wide one used in solid ink printing, the new modular print heads can scale to fit multiple kinds of printers using different ink and different media. Xerox says it can output 300 dpi (dots per inch) and the cost of each drop is improved greatly. Despite the improvements, new print heads do mean needing to buy a new printer to take advantage of the technology.

Xerox says this will be available in consumer desktop printers within a year.