Printhead capping arrangement
View Patent ↗A pagewidth inkjet printer is described which includes printhead ( 11 ) with a plurality of print nozzles ( 30 ) for ejecting ink drops towards a print medium. A space is defined between the nozzles and a nozzle guard ( 43 ) with a series of apertures ( 44 ) aligned with the nozzles. During printing operation, positive air pressure is supplied to this space, the air exiting the space through the apertures, preventing blockage by paper dust. When not printing, the air supply is closed off by air valve member ( 66 ) and a capping member ( 80 ) on a rotary platen ( 14 ) contracts the printhead to maintain a closed atmosphere at the surface of the nozzles, reducing drying of ink on the nozzles.
1. An inkjet printer, including a printhead having a plurality of print nozzles for selectively ejecting drops of ink towards a print medium passing said nozzles, the printhead further having a structure that defines a space adjacent said nozzles, and a capping mechanism located on a platen member of the printer; such that,
when the printer is in an operational mode, the structure allows drops of ink ejected from the nozzles to strike the print medium while preventing contact between the nozzles and foreign bodies larger than a threshold size; and
when the printer is in a non-operational mode, the platen member moves the capping mechanism into a capping position in which it is engaged, with the structure to provide a closed atmosphere in the space.
2. An inject printer according to claim 1 wherein said structure includes a nozzle guard, the space being defined between the nozzle guard and said nozzles.
3. An inkjet printer according to claim 2 wherein said nozzle guard has a plurality of apertures aligned with said nozzles so that ink drops ejected from said nozzles pass through said apertures.
4. An inkjet printer according to claim 3 wherein said plurality of nozzles are arranged in an array extending across an A4 pagewidth.
5. An inkjet printer according to claim 4 wherein said nozzles comprise micro-electromechanical devices.
6. An inkjet printer according to claim 5 wherein said nozzles are arranged in a plurality of print modules.
7. An inkjet printer according to claim 6 wherein each print module is associated with a respective nozzle guard to define a respective space.
8. An inkjet printer according to claim 7 further including air supply means providing positive air pressure to each said space when the printer is in a printing operational mode and discontinuing said air supply when said printer is in said non-printing operational mode.
9. An inject printer according to claim 3 wherein said capping mechanism covers said nozzle guard to seal the space from atmosphere.
10. An inkjet printer according to claim 9 wherein said capping mechanism further includes means for discontinuing an air supply to said printer.
11. An inject printer according to claim 3 wherein said capping mechanism includes a seal member contacting said printhead in a locus surrounding said nozzle guard apertures.
12. An inkjet printer according to claim 1 further including air supply means providing positive air pressure to said space when the printer is in a printing operational mode and discontinuing said air supply when said printer is in said non-printing operational mode.
13. An inkjet printer according to claim 1 wherein said platen member is rotatable to bring said capping mechanism into engagement with said structure.
14. An inkjet printer according to claim 13 wherein said printhead extends across an A4 pagewidth, and wherein said platen member and capping mechanism also extend across said pagewidth.