A View from David Zax
An Inkjet Nozzle Inspired by the Human Eye
When biomimicry opens a nozzle, it closes a loop.
This may or may not be a problem you knew you had, but your inkjet printer’s nozzle occasionally clogs. Our technological age won’t stand for that, so researchers at Missouri University have designed a new sort of nozzle that won’t clog. The interesting bit? It’s modeled after the human eye.
“The nozzle cover we invented was inspired by the human eye,” said Jae Wan Kwon, associate professor in the College of Engineering at MU, in a release, who developed the mechanism with grad student Riberet Almieda. “The eye and an ink jet nozzle have a common problem: they must not be allowed to dry while, simultaneously, they must open.
How does the eye prevent its own “clogging”? How does it keep itself from dying out? Simply enough: eyelids spread a thin film of oil atop the thin layer of tears on the eye’s surface. (Strange to think of them as “tears” before they pour down your cheeks, but I suppose they’re tears in the same sense that the water stored in clouds is rain.)
Kwon couldn’t replicate this model exactly–you can’t have mechanical “eyelids” (in practice, shutters) on the tiny scale of an inkjet nozzle. Surface tension would prevent them from opening and closing properly. But Kwon had the insight that you could use an electric field to move a droplet of oil in and out of position.
Though a little difficult to visually parse, MU says that this video gives a microscopic view of the nozzle in action.
Why do we care if our inkjet nozzles clog? The problem of a clogged nozzle might appear pretty minor. Rarely does it cease the printer from functioning altogether; rather, it simply necessitates an extra burst of ink to push through the dried bit. But consider the cost of ink, and then multiply that wasted burst across all the inkjet printers in the world–and suddenly you realize that massive amounts of ink, and money, can be saved in the aggregate.
Also, Kwon’s invention can be used in devices similar to inkjets–devices that may use an even more precious kind of “ink.” Kwon explains: “Other printing devices use similar mechanisms to ink jet printers. Adapting the clog-free nozzle to these machines could save businesses and researchers thousands of dollars in wasted materials. 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.”
All of this evokes an odd vision, then: One day, perhaps Kwon’s invention, inspired by the human eye, might be a crucial component in the printing of a replacement eye.