Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1998-12-17
2001-06-26
Le, N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S013000
Reexamination Certificate
active
06250738
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to inkjet printhead construction, and more particularly, to a wide-array inkjet printhead construction.
There are known and available commercial printing devices such as computer printers, graphics plotters and facsimile machines which employ inkjet technology, such as an inkjet pen. An inkjet pen typically includes an ink reservoir and an array of inkjet printing elements, referred to as nozzles. The array of printing elements is formed on a printhead. Each printing element includes a nozzle chamber, a firing resistor and a nozzle opening. Ink is stored in the ink reservoir and passively loaded into respective firing chambers of the printhead via an ink refill channel and ink feed channels. Capillary action moves the ink from the reservoir through the refill channel and ink feed channels into the respective firing chambers. Conventionally, the printing elements are formed on a common substrate.
For a given printing element to eject ink a drive signal is output to such element's firing resistor. Printer control circuitry generates control signals which in turn generate drive signals for respective firing resistors. An activated firing resistor heats the surrounding ink within the nozzle chamber causing an expanding vapor bubble to form. The bubble forces ink from the nozzle chamber out the nozzle opening.
A nozzle plate adjacent to the barrier layer defines the nozzle openings. The geometry of the nozzle chamber, ink feed channel and nozzle opening defines how quickly a corresponding nozzle chamber is refilled after firing. To achieve high quality printing ink drops or dots are accurately placed at desired locations at designed resolutions. It is known to print at resolutions of 300 dots per inch and 600 dots per inch. Higher resolution also are being sought.
There are scanning-type inkjet pens and non-scanning type inkjet pens. A scanning-type inkjet pen includes a printhead having approximately 100-200 printing elements. A non-scanning type inkjet pen includes a wide-array or page-wide-array printhead. A page-wide-array printhead includes more than 5,000 nozzles extending across a pagewidth. Such nozzles are controlled to print one or more lines at a time.
In fabricating wide-array printheads the size of the printhead and the number of nozzles introduce more opportunity for error. Specifically, as the number of nozzles on a substrate increases it becomes more difficult to obtain a desired processing yield during fabrication. Further, it is more difficult to obtain properly sized substrates of the desired material properties as the desired size of the substrate increases.
In the related matters, cross-referenced above, a scalable wide-array printhead structure is described in which multiple inkjet printhead dies are mounted to a carrier substrate. One of the challenges in forming a wide array printhead with multiple printhead dies is the number of interconnections which occur. Many electrical interconnections are needed. In addition, many ink connections are required to deliver the inks. In a three-color, four inch, wide-array printhead having 34 printhead dies, for example, there are at least 102 fluid interconnections (i.e., 3×34=102). This invention is directed toward an inkjet printing device having an ink manifold.
SUMMARY OF THE INVENTION
According to the invention, an inkjet printing system includes a scalable printhead with an ink manifold. The scalable printhead is formed by mounting an ink manifold and multiple thermal inkjet printhead dies to a carrier substrate. Each printhead die includes a plurality of printing elements. Each printing element includes a nozzle chamber, a firing resistor and a nozzle opening. The nozzle openings are located along one surface of each die. One or more refill slots are located along an opposite surface of each printhead die. The refill slot is fluidly connected to each nozzle chamber allowing ink to flow into the die through the refill slot(s), then into the nozzle chambers. By prescribing a different number of printhead dies to a carrier substrate for different embodiments, different sized printhead embodiments are achieved.
According to one aspect of the invention, the ink manifold is coupled to the carrier substrate. The carrier substrate is machined to include through-openings. There is a through-opening for each refill slot among the multiple printhead dies. A first end of a given through-opening connects to a refill slot of a corresponding printhead die. An opposite, second end of the through-opening connects to the ink manifold. Thus, the ink manifold is coupled to the carrier substrate at the respective second ends of the through-openings.
According to another aspect of this invention, the ink manifold includes an inlet for coupling to an ink supply reservoir. In some embodiments the ink manifold includes a plurality of inlets for coupling to a plurality of ink supply reservoirs, (e.g., reservoirs of different color ink, such as black, cyan, magenta and yellow ink reservoirs). In still other embodiments, there also is an outlet for each inlet. Ink flows into the manifold through an inlet, travels through channels within the manifold, then is cycled out through the corresponding outlet. Some of the ink, however, exits the manifold through fill openings adjacent the carrier substrate through-openings so that ink may travel to the printing element nozzle chambers. Ink leaves the manifold outlet and fill openings.
In varying embodiments the carrier substrate is formed of silicon or a multilayer ceramic. The carrier substrate includes the through-openings, and also includes electrical interconnection pathways for routing signals among the plurality of printhead dies. In the multilayer ceramic substrate embodiment, the carrier substrate includes multiple electrical interconnection planes for routing the electrical signals.
According to another aspect of the invention, the inkjet printing system includes multiple ink reservoirs, one for each color of ink. Separate inlets, manifold channels, outlets, and fill openings are formed in the ink manifold to flow ink from a respective reservoir through the manifold to the carrier substrate and printhead dies. A first fluid path occurs from a first inlet of the manifold through a first set of the fill openings through corresponding carrier substrate through-openings to corresponding printhead die ink refill slots. A second fluid path occurs from a second inlet of the manifold through a second set of the fill openings through corresponding carrier substrate through-openings to corresponding printhead die ink refill slots.
The inkjet printing system also includes a housing, a mounting assembly, a media transport assembly, and a controller. The inkjet printhead is positioned at the mounting assembly and includes a plurality of printing elements. A print zone occurs adjacent to the plurality of printing elements along a media path. The media transport assembly moves a media sheet along the media path into the print zone. The controller determines a timing pattern for ejecting ink from the plurality of printing elements onto the media sheet.
According to another aspect of the invention, one method for loading the plurality of inkjet nozzles includes replacing the internal reservoir of the pen, and flowing ink from the internal reservoir into the ink manifold. The manifold has an inlet coupled to the internal reservoir. The ink manifold fluidly connects the inlet to a plurality of through-openings of the carrier substrate, which in turn are coupled to respective ink refill slots of a plurality of printhead dies. Ink flows into the respective ink refill slots, then into a plurality of nozzle chambers. Ink is fired from the nozzle chambers to print onto a media sheet.
One advantage of the invention is that a manifold formed separate from the carrier substrate and mounted to the carried substrate is that new printhead designs may be more rapidly prototyped and tested. In addition, for a multilayer ceramic carrier substra
Beerling Timothy E
Boyd Melissa D
Pearson James W
Waller David J
Wong Marvin G
Hewlett--Packard Company
Le N.
Nguyen Lamson D.
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