Nozzle guard for a printhead
View Patent ↗An ink jet printhead has a number of printhead chips ( 10 ). Each printhead chip ( 10 ) has a wafer substrate ( 16 ). A plurality of nozzle arrangements ( 10 ) is positioned on the wafer substrate. Each nozzle arrangement ( 22 ) has nozzle chamber walls and a roof wall that define a nozzle chamber ( 34 ) and a nozzle opening ( 24 ) in fluid communication with the nozzle chamber. An actuator ( 28 ) is operatively arranged with respect to each nozzle arrangement ( 10 ) to eject ink from the nozzle chamber through the nozzle opening. A nozzle guard ( 80 ) is positioned over the printhead chip. The nozzle guard has a support structure ( 86 ) and a planar cover member ( 82 ). The planar cover member is positioned on the support structure. The planar cover member defines a plurality of passages ( 84 ). Each passage ( 84 ) is in register with a respective nozzle opening ( 24 ). The planar cover member ( 82 ) is less than 300 microns thick.
1. An ink jet printhead which comprises:
an array of nozzles on a wafer substrate, each nozzle having a nozzle chamber, a nozzle opening in fluid communication with said nozzle chamber and a thermal bend actuator operatively arranged with respect to the nozzle chamber to eject ink through the nozzle opening; and
a nozzle guard comprising a cover member having a thickness of less than approximately 300 microns which covers the array of nozzles, the cover member defining a plurality of passages, each passage being spaced from and in register with a respective nozzle opening such that ink ejected through the nozzle openings passes through the respective passages.
2. An ink jet printhead as claimed in claim 1 , wherein the nozzle guard further comprises a plurality of struts which support the cover member in spaced relationship with the nozzles.
3. An ink jet printhead as claimed in claim 1 , wherein the nozzle guard is part of the wafer substrate.
4. An ink jet printhead as claimed in claim 3 , wherein the wafer substrate is a silicon substrate.