Use Water As Printer Ink to Save Money and Trees

With the news that HP has won more lawsuits to stop ink cartridge makers producing knock-off cartridges for their printers, anything that hints at cheaper printing is good news to me. Sure, it’s better to save trees and not print at all, but sometimes you just need to get things in hard copy.

A team of chemists in China and America have now come up with a way to print on specially treated paper using water, as opposed to ink—and as well as reducing costs, the new technique would save paper. That’s because the water “ink” disappears after 22 hours, so the paper can be re-used.

An added advantage the researchers don’t mention is surely the potential to write secret notes that will self-destruct in time, like an analog Snapchat.

While the printing technology is the same as if you were using ink, the process requires paper to be treated with dye. But the cost of doing that is soon recouped, as re-using the same piece of paper 50 times would bring the price down to one percent of conventional inkjet methods, according to chemist Sean Xiao-An Zhang. He co-authored a paper on the “water-jet” printing technique published in Nature Communications.

“We are using a commercially available inkjet printer,” Zhang told Discovery News. “We just filled the cartridges with water and put it back. It’s like normal printing. The magic is in the paper.” Phys.org unearthed a video that shows a comparison of a water-jet print with an inkjet print (about two and a half minutes in); it looks perhaps a little less sharp, but still pretty clear.

The dye on the paper, which you can’t see, is revealed when the water hits it. It sounds like those colouring books you had when you were a kid that turn all multicoloured when you paint them with water—but in this case the colours fade when the print evaporates. AFP reports Zhang and his team have developed four colours—blue, magenta, gold, and purple.

Over at Smart Planet, Tyler Falk points out that one advantage of the method is that it uses a conventional printer, so if you need to print something that lasts longer than a day you could just replace the water cartridge with a regular ink cartridge. But he Consumer Report noted the cheapest ink can cost more than champagne ounce for ounce, while more expensive inks are on a par with Chanel No. 5.

In the meantime, for all your throwaway notes, you could save money from the cartridge companies’ coffers.