Based on the function of the human eye, engineers at the University of Missouri (Columbia) have invented a clog-preventing nozzle. Developed by Jae Wan Kwon, associate professor in the college of engineering, the technology uses a droplet of silicone oil to cover the opening of the nozzle when it is not in use, similar to the film of oil that keeps a thin layer of tears from evaporating off the eye. On the surface of the human eye, eyelids spread the film of oil over the layer of tears. However, because mechanical shutters like eyelids would not work at the tiny scale of the ink jet nozzle, the droplet of oil for the nozzle is easily moved in and out of place using an electric field.

“The nozzle cover we invented was inspired by the human eye,” Kwon remarks. “The eye and an ink jet nozzle have a common problem: they must not be allowed to dry while, simultaneously, they must open. We used biomimicry, the imitation of nature, to solve human problems.”

To clear a clogged nozzle in most ink jet printers, a burst of fresh ink breaks through the crust of dried ink that forms if the machine isn’t constantly in use. Over time, this cleaning operation can waste ink. Kwon’s invention eliminates the need to inject fresh ink to unclog the nozzle, reducing waste in home and office printers. But it could find use in medical device applications as well.

“Adapting the clog-free nozzle to these machines could save businesses and researchers thousands of dollars in wasted materials," Kwon notes. "For example, biological tissue printers, which may someday be capable of fabricating replacement organs, squirt out living cells to form biological structures. Those cells are so expensive that researchers often find it cheaper to replace the nozzles rather than waste the cells. Clog-free nozzles would eliminate the costly replacements.”