Printhead with droplet redirecting nozzle guard
View Patent ↗A printhead is provided having an ejection surface having a plurality of nozzles for ejecting droplets and a nozzle guard positioned over the ejection surface and having a plurality of channels therethrough aligned with the nozzles. The channels have hydrophobic sidewalls and are radially flared with respect to the ink ejection surface such that droplets which are ejected from the nozzles with misdirection rebound off the channel sidewalls to pass through the channels.
1. A printhead comprising:
an ejection surface having a plurality of nozzles for ejecting droplets; and
a nozzle guard positioned over the ejection surface and having a plurality of channels therethrough aligned with the nozzles, wherein the channels have hydrophobic sidewalls and are radially flared with respect to the ink ejection surface such that droplets which are ejected from the nozzles with misdirection rebound off the channel sidewalls to pass through the channels.
2. A printhead according to claim 1 , wherein the nozzles are configured so that the ejected droplets have sufficient surface energy to rebound off the channel sidewalls intact.
3. A printhead according to claim 1 , wherein the channels are substantially parabolic in cross-section.
4. A printhead according to claim 1 , wherein the rebounded droplets follow a trajectory substantially perpendicular to the ink ejection surface.
5. A printhead according to claim 1 , wherein the nozzle guard is formed from a polymeric material.
6. A printhead according to claim 1 , wherein the nozzle guard is formed from photoresist.
7. A printhead according to claim 6 , wherein the photoresist is UV cured and/or hardbaked.
8. A printhead according to claim 1 , wherein each channel has a length in the range of 10 to 200 microns.
9. A printhead according to claim 1 , configured as a pagewidth printhead.
10. A printhead according to claim 1 , wherein the printhead has a nozzle density sufficient to print images at up to 1600 dpi.