Piezoelectric inkjet printheads use piezoelectric actuators that change shape to generate pressure pulses inside ejection chambers to force fluid out through nozzles. Rex circuits are often used to carry electrical signals to the printheads to drive the piezoelectric actuators.
The same part numbers designate the same or similar parts throughout the figures.
A new piezoelectric inkjet printhead architecture has been developed to substantially increase the density of nozzles that can be integrated into each printhead. Driver ICs located immediately adjacent to the printhead die include amplifiers for each piezoelectric actuator and provide a drive waveform tuned to each actuator's electromechanical response. A printhead assembly with a new mounting scheme and flex circuit interconnect has been developed to support the new high nozzle density printhead architecture. In one example, multiple printheads are arranged along a line in a staggered configuration in which each printhead in a group of far printheads overlaps a printhead in a group of near printheads. In this example, each printhead in the assembly includes a pedestal, a printhead die mounted to the pedestal, a pair of ICs connected to the printhead die to drive fluid ejector elements in the die, and a flex circuit connected to the ICs. The ICs are mounted to the pedestal on opposite sides of the printhead die, in plane with and immediately adjacent to the die. The flex circuit has a body and a tail extending from the body in the same direction as all of the other flex circuit tails. The body of the flex circuit surrounds the printhead die and covers the ICs, and the tail of each flex circuit in a far printhead extends past a pedestal in a near printhead.
The pedestals provide a sufficiently large platform to mount two ICs and the flex circuit while still allowing the flex circuits from far printheads to pass the near printheads so that all flex circuits can be efficiently routed to a single PCA on one side of the printhead assembly. The body of the flex circuit surrounding the printhead die enables routing signal traces to ICs on both sides of the die through a single tail on one side of the die. Also, the exposed exterior of the flex circuit body surrounding each printhead die may be used as a capping surface to seal the fluid dispensing nozzles when the printhead is capped during periods of inactivity, thus eliminating the need for an additional shroud or other discrete part to provide the capping surface.
Examples of the new printhead assembly are not limited to piezoelectric inkjet printing, but may be implemented in thermal inkjet and other inkjet type dispensing devices. The examples shown in the Figures and described herein illustrate but do not limit the disclosure, which is defined in the Claims following this Description.
As used in this document, a “printhead die” means that part of an inkjet printer or other inkjet type dispenser that can dispense fluid from one or more openings; and an “IC” means an integrated circuit. A “printhead die” is not limited to printing with ink and other printing fluids but also includes inkjet type dispensing of other fluids and/or for uses other than printing.
An inkjet printhead die 24 is a typically complex MEMS (microelectromechanical system) formed on a silicon substrate. In the example shown in the figures, fluid ejector elements and other components in each printhead die 24 are electrically connected to ASICs (application specific integrated circuits) or other suitable driver ICs 32, 34 located immediately adjacent to die 24. Each IC 32, 34 is connected to a printer controller or other source of power and control signals through traces (not shown) in a flex circuit 36. The electrical connections between die 24 and ICs 32, 34 and between ICs 32, 34 and connections to flex circuit 36 may be made, for example, with wire Bonds—tiny wires (not shown) connecting bond pads 38 on die 24 to bond pads 40 on ICs 32, 34 and connecting bond pads 42 on ICs 32, 34 to bond pads 44 on flex circuit 36. For clarity, the hundreds or even thousands of signal traces and bond wires are not shown, and a reduced number of the equally numerous individual bond pads 38-44 are exaggerated in size on die 24. ICs 32, 34 and flex circuit 36. Although any suitable technique may be used to make the electrical connections among die 24, ICs 32, 34 and flex circuit 36, wire bonds may be desirable in many implementations because wire bonding technology is well developed to accurately form and connect the small, high density bond pads needed to support higher density nozzle arrays on die 24.
As best seen in
Referring again to
The body 70 of flex circuit 36 surrounds printhead 24 to carry signal traces from both ICs 32, 34 to a tail 72 that extends from body 70 on only one side of the printhead. The mounting surfaces bordered by perimeter flange 66 on each pedestal 14 are large enough to support flex circuit body 70 surrounding nozzle arrays 29. Accordingly, the electrical connections to all printheads 12A-12F may be located on just one side of the printhead assembly 10. Where the arrangement of pedestals 14 might otherwise obstruct routing all flex circuit tails 72 to one side of the printhead assembly 10, as shown in
The printhead configuration shown in
As best seen in
Printhead assembly 10 may include interchangeable ICs 32, 34 oriented 180′ from one another on each side of each printhead die 24. Similarly, interchangeable pedestals 14 oriented 180′ from one another in far and near printhead groups 20, 22 may be used to support dies 24 and ICs 32, 34. While a pair of ICs 32, 34 flanking both sides of each die 24 is shown, other suitable configurations are possible. For example, a single drive IC flanking one side of a printhead die may be adequate in some implementations.
“A” and “an” as used in the Claims means one or more.
As noted at the beginning of this Description, the examples shown in the figures and described above illustrate but do not limit the disclosure. Other examples are possible. Therefore, the foregoing description should not be construed to limit the scope of the disclosure, which is defined in the following Claims.
Filing Document | Filing Date | Country | Kind |
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PCT/US2014/035083 | 4/23/2014 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2015/163862 | 10/29/2015 | WO | A |
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Entry |
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Wijshoff, H.; The Dynamics of the Piezo inkjet Printhead Operation; http://www.sciencedirect.com/science/article/pii/S0370157310000827 >; Jun. 2010. |
Number | Date | Country | |
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20170028713 A1 | Feb 2017 | US |