Title of Invention

A PRINTHEAD FOR AN INKJET PRINTER

Abstract

A printhead for an inkjet printer, the printhead comprising: a plurality of print nozzles for selectively ejecting drops of ink towards a print medium passing said nozzels; an enclose4d space situated between said nozzles and said print medium so that ink drops ejected from the nozzles pass through said enclosed space en route to the print medium; and air supply arrangement supplying positive air pressure to said enclosed space.

Full Text

"Air Supply Arrangement for a Printer" BACKGROUND PF THE INVENTION The present invention relates to an air supply arrangement for a printer. More particularly, though not exclusively, the invention relates to an air supply arrangement for an A4 pagewidth drop on demand printhead capable of printing up to 1600 dpi photographic quality at up to 160 pages per minute. The overall design of a printer in which the arrangement can be utilized revolves around the use of replaceable printhead modules in an array approximately 8 inches (20 cm) long. An advantage of such a system is the ability to easily remove and replace any defective modules in a printtead array. This would eliminate having to scrap an entire printhead . if only one chip is defective. A printhead module in such a printer can be comprised of a "'Memjef" chip, being a chip having mounted thereon a vast number of thermo-actuators in micro-mechanics and micro-electromechanical systems (MEMS). Such actuators might be those as disclosed in U.S. Patent No. 6,044,646 to the present applicant, however, there might be other MEMS print chips. The printhead, being the environment within which the air supply arrangement of the present invention is to be situated, might typically have six ink chambers and be capable of printing four color process (CMYK) as well as infra-red ink and fixative. Each printhead module receives ink via a distribution molding that transfers the ink- Typically, ten modules butt together to fonn a complete eight inch printhead assembly suitable for printing A4 paper without the need for scanning movement of the printhead across the paper width. The printheads themselves are modular, so complete eight inch printhead arrays can be configured to form printheads of arbitrary width. Additionally, a second printhead assembly can be mounted on the opposite side of a paper feed path to enable double-sided high speed printing, CO-PENDING APPLICATIONS Various methods, systems and apparatus relating to the present invention are disclosed in the following copending applications filed by the applicant or assignee of the present invention'simultaneously with the present application: PCT/AUU00/00518, PCT/AUU00/00519, PCT/AUU00/00520, PCT/AUU00/0052]. PCT/AUU00/00522. PCT/AUU00/00523, PCT/AUUU00/00524, PCT/AUUU00/00525, PCT/AUUU00/Q0526, PCT/AU0O/0O527, PCT/AUU00/00528, PCT/AUU00/00529. PCT/AUU00/00530, PCT/AUU00/00531. PCT/AUU00/00532, PCT/AU0O/OG533. PCr/AUU00/00534, PCT/AUU00/00535, PCT/AUUU00/00536, PCT/AUU00/00537, PCT/AUUU00/00538, PCT/AUU00/00539, PCT/AUU00/00540, PCT/AUU00/00541. PCT/AUU00/00542, PCT/AUU00/00543, PCT/AUU00/00544, PCT/AUUU00/00545, PCT/AUUU00/00547, PCT/AUU00/00546, PCT/AUUU00/00554, PCT;AUUU00/00556, PCT/AUUU00/00557, PCT/AUUU00/00558, PCT/AUU00/00559, PCT/AUUU00/00560, PCT/AUU00/00561, PCT/AUU00/00562, PCT/AUU00/00563, PCT/AUU00/00564, PCT/AUU00/00565, PCT/AUUU00/00566, PCT/AUUU00/O0567. PCT/AUUU00/00568, PCT/AUU00/00569, PCT/AUU00/00570, PCT/AUU00/00571. PCT/AUU00/00572, PCT/AUU00/00573, PCT/AUU00/00574. PCT/AUU00/00575, PCT/AUU00/00576, PCr/AUU00/00577, PCT/AUU00/00578, PCT/AUU00/00579, PCT/AUU00/00581, PCT/AUU00/00580, PCT/AUU00/00582, PCT/AUU00/00587. PCT/AUU00/00588, PCT/AUU00/00589, PCT/AUU00/00583, PCT/AUU00/00593, PCT/AUU00/00590, PCT/AUU00/00591, PCT/AUU00/00592, PCT/AUU00/00584, PCT/AUU00/00585, PCT/AUU00/00586, PCT/AUU00/00594. PCT/AUU00/00595, PCT/AUU00/00596, PCT/AUU00/00597, PCT/AUU00/00598, PCT/AUU00/00516, PCT/AUU00/00517, PCT/AUU00/00511, PCT/AUU00/00501, PCT/AUU00/00502, PCr/AUU00/00503, PCT/AUU00/00504. PCT/AUU00/00505, PCT/AUU00/00506, PCT/AUU00/00507. PCr/AUU00/00508, PCT/AUU00/00509, PCT/AUU00/00510, PCT/AUU00/00512, PCT/AUU00/00513, PCT/AUU00/00514. PCT/AUU00/00515 The disclosures of these co-pending applications are incorporated herein by cross-reference. AMENDED CLAIMS [received by the International Bureau on 29 August 2001 (29.08.01); original claim 1 amended; remaining claims imchanged (1 page)] WE CLAIMS 1. A printhcad for an Inkjet printer, including a plurality of print nozzles for selectively ejecting drops of ink towards a print medium passing said nozzles, an enclosed space situated between said nozzles and said print medium so that ink drops ejected from the nozzles pass through said enclosed space en route to the print medium, further including air supply means supplying positive air pressure to said enclosed space, 2. A printhead for an inKJet printer according to claim 1 wherein said space is formed between said nozzles and a nozzle guard. 3. A printhead for an Inkjet printer according to claim 2 wherein said nozzle guard has a plurality of apertures aligned with said nozzles so that mk drops ejected from said nozzles pass through said apertures. 4. A printhead for an inkjet printer according to claim 1 wherein.said air supply is discontinued when said printer is in a non-printing operational mode. . 5. A printhead for an inkjet printer according to'claim3 wherein said pluarity of nozzles arc arranged in an array extending across an A4 pagewidth. 6. A printhead for an inkjet printer according to claim 5 wherein said nozzles comprise micro-electromechanical devices. 7. A printhead for an inkjet printer according to claim 6 wherein said nozzles are arranged in a plurality of print modules. 8. A printhead for an inkjet printer according to claim 7 wherein each print module is associated with a respective nozzle guard to define a respective space. 9. A printhead for an inkjet printer according to claim 8 wherein said air supply means supplies positive air pressure to each said space. 10. A printhead for an inkjet printer according to claim 5 including a phirality of said spaces corresponding to respective portions of said nozzle array, wherein said air supply means includes a common air intake, air filtration means and means for distributing pressurized air to each said space. 11. A printhead for an inkjet printer according to claim 10 wherein said air filtration means are provided in a replaceable ink cassette of the printer. 12. A printhead for an inkget printer according to claim 10 including air valve means for shutting off air supply to said spaces when said printer is in a non-printing operational mode. 13. A printhead for an inlget printer according to claim 12 wherein said air valve means includes an air distribution duct having a plurality of air passages in communication with respective of said spaces and an air valve tnember with a plurality of apertures corresponding to said air passages, said valve member being movable between a valve open position in which said air apertures are in communication with said air passages and a valve closed position in which said air apertures are not in communication with said air passages. 14. A printhead for an inkjet printer according to claim 13 wherein air is distributed to said spaces from said air passages by a multi-layer laminated distribution structure. 15. A printhead for an inkjet printer according to claim 14 wherein said laminated distribution structure includes a plurality of air holes extending through at least some of said layers and transverse air passages formed between two adjacent ones of said layers, said transverse air passages leading to said spaces. 16. A printhead for an inkjet printer, substantially as hereinabove described and illustrated with reference to the accompanying drawings.

Documents:

in-pct-2002-che-1907-abstract.pdf

in-pct-2002-che-1907-claims duplicate.pdf

in-pct-2002-che-1907-claims original.pdf

in-pct-2002-che-1907-correspondance others.pdf

in-pct-2002-che-1907-correspondance po.pdf

in-pct-2002-che-1907-descripition complete duplicate.pdf

in-pct-2002-che-1907-descripition complete original.pdf

in-pct-2002-che-1907-drawings.pdf

in-pct-2002-che-1907-form 1.pdf

in-pct-2002-che-1907-form 19.pdf

in-pct-2002-che-1907-form 26.pdf

in-pct-2002-che-1907-form 3.pdf

in-pct-2002-che-1907-form 5.pdf

in-pct-2002-che-1907-pct.pdf