Clogged
printer nozzles waste time and money while reducing print quality.
University of Missouri engineers recently invented a clog-preventing
nozzle cover by mimicking 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. “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.”
Kwon’s
invention uses a droplet of silicone oil to cover the opening of the
nozzle when 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,
at the tiny scale of the ink jet nozzle, mechanical shutters like
eyelids would not work, as they would be stuck in place by surface
tension. Instead, the droplet of oil for the nozzle is easily moved in
and out of place by an electric field.
Kwon
said this invention could make home and office printers less wasteful.
To clear a clogged nozzle in most ink jet printers, a burst of fresh ink
breaks through the crust of dried ink which forms if the machine isn’t
used constantly. Over time this cleaning operation can waste a large
amount of expensive ink. Kwon’s invention eliminates the need to waste
that squirt of ink.
“Other
printing devices use similar mechanisms to ink jet printers,” Kwon
said. “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.”
Similarly,
rapid prototyping systems used by engineers and product designers emit
streams of liquid plastic through nozzles like those on an inkjet
printer. The thick, sticky liquid used in the devices can make it
necessary to replace the whole nozzle when they become clogged. These
specialty printer parts can cost thousands of dollars.
MU
engineering doctoral student Riberet Almieda worked with Kwon on the
oil droplet nozzle cover. A paper documenting the discovery was
published in the Journal of Microelectromechanical Systems.
Source: University of Missouri
