Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-02-15
2003-03-18
Nguyen, Thinh (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S019000
Reexamination Certificate
active
06533390
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a printer. More particularly, the invention relates to a method of manufacturing a printhead assembly for a pagewidth printer and to a printhead assembly for a pagewidth printer.
BACKGROUND TO THE INVENTION
Pagewidth printheads have the advantage of being able to print rapidly but are constituted by a very large number of nozzles. Should any of these nozzles be defective, an inadequate print quality may result.
SUMMARY OF THE INVENTION
According to a first aspect of the invention, there is provided a method of manufacturing a printhead assembly for a pagewidth printer, the method including the steps of
providing a first printhead including a plurality of inkjet nozzles constructed using microelectromechanical techniques;
selecting a second printhead of the same construction as the first printhead; and
matching the first printhead to the second printhead by ensuring that no corresponding, paired nozzles of the two printheads are both defective.
It will be appreciated that, in practice, the selection process for the second printhead may involve a number of selections to ensure that there are no paired nozzles of the two printheads eventually selected which are both defective.
In this specification, unless the context clearly indicates otherwise, the term “pagewidth printhead” or “pagewidth printer” is to be understood as a printhead or printer having a printing zone that prints one line at a time on a page, the line being parallel either to a longer edge or a shorter edge of the page. The line is printed as a whole as the page moves past the printhead and the printhead is stationary, ie it does not raster or traverse the page.
The method may include constructing each printhead from a plurality of segments arranged in end-to-end relationship.
In one embodiment of the invention, the method may include characterising and matching printhead defects one segment at a time during construction of the printheads. In this case, it will be appreciated that the testing of the nozzles of the relevant segments occurs without ink before integration with an ink path.
In another embodiment of the invention, the method may include characterising and matching printhead defects after each printhead has been assembled in its entirety. In this embodiment, the method may include testing the nozzles with ink after integration with an ink path.
According to a second aspect of the invention, there is provided a printhead assembly for a pagewidth printer, the assembly including a pair of printheads, each printhead including a plurality of inkjet nozzles constructed using microelectromechanical techniques, the printheads being selected and matched so that no two paired nozzles of the printheads are both defective.
Each printhead may be constituted by a plurality of segments arranged in end-to-end relationship.
Once again, in one embodiment of the invention, the printhead defects may be characterised and matched one segment at a time. The nozzles may then be tested without ink before integration with an ink path.
In another embodiment of the invention, the printhead defects may be characterised and matched after completion of the entire printhead. In this case, the nozzles may be tested with ink after integration with an ink path.
REFERENCES:
patent: 5124720 (1992-06-01), Schantz
patent: 5587730 (1996-12-01), Karz
patent: 5665249 (1997-09-01), Burke et al.
patent: 5929875 (1999-07-01), Su et al.
patent: 6039438 (2000-03-01), Beerling
patent: WO 99/08875 (1999-02-01), None
Nguyen Thinh
Silverbrook Research Pty Ltd
LandOfFree
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