In South Korea, Samsung Electronics product designer Hwan Ju Jeon has created a prototype printer that uses used coffee grounds as ink.
While soy-based inks exist as an alternative to conventional, petroleum-based printer inks, the RITI coffee printer concept envisions using material that would otherwise be household trash.
“Perhaps the most exciting aspect of this printer design is that it uses a basic household product that traditionally goes to waste,” according to a write-up in How Stuff Works. “Load in some coffee grounds and water, and you have homemade ink. And besides coffee grounds, the printer can use tea dregs. The grounds or dregs and water are loaded into a reusable “ink case” rather than a wasteful ink cartridge.”