Inkjet Recording Head Vertical Wire Routing
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Solution Overview
Problem
The existing inkjet recording heads with piezoelectric actuators face challenges in reducing production costs and increasing production yield due to high wire density, which is exacerbated by the need to form pressure chambers at higher densities, leading to reliability issues with electrical connections and potential cross-talking phenomena.
Innovation Solution
The design allows electric wires to overlap portions of adjacent pressure chambers, enabling wider wire placement and reduced density, while maintaining reliable electrical connections and preventing cross-talking by strategically forming openings in the common electrode to prevent electric field generation in overlapping areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If pressure chambers are formed at higher density to reduce head size, then the size of the inkjet recording head is reduced, but the pitch of electric wires must be decreased which raises production cost and lowers production yield and reliability
Solution Approach 1:
The patent allows electric wires to extend in the vertical direction (perpendicular to the reference plane) rather than only in the horizontal plane. This three-dimensional wire routing enables wires to connect to individual electrodes without being constrained to the two-dimensional plane between pressure chambers, thus maintaining adequate wire pitch even when pressure chambers are densely packed.
2Measurement precision
If pressure chambers are formed at higher density to improve printing quality, then printing quality is improved, but wire density increases which lowers production yield
Solution Approach 1:
By enabling electric wires to route in the vertical dimension, the patent decouples wire placement constraints from the horizontal density of pressure chambers. This allows pressure chambers to be densely arranged for high printing quality while wires can route overhead or underneath without competing for the same two-dimensional space, thereby maintaining production yield.
3Volume of moving object
If wire pitch is decreased to accommodate higher pressure chamber density, then head size is reduced, but production cost increases
Solution Approach 1:
The patent resolves this contradiction by moving wire routing into the third dimension. Wires can extend vertically above or below the pressure chamber plane, eliminating the need to decrease wire pitch in the horizontal plane. This maintains standard wire spacing for cost-effective manufacturing while achieving compact head size through vertical wire routing.
4Reliability
If electric wires are located only in areas between pressure chambers, then cross-talking is prevented, but the area for wire placement is limited which increases wire density
Solution Approach 1:
The patent allows electric wires to occupy the vertical space above and below the pressure chamber plane. This three-dimensional wire placement provides abundant space for wire routing without increasing horizontal wire density. Wires can extend vertically to connect to individual electrodes while maintaining separation between adjacent wire paths, thus preventing cross-talking.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces production costs, increases the number of pressure chambers without increasing wire density, enhances printing speed and quality, and effectively prevents cross-talking, ensuring reliable ink ejection.
Implementation Method 1
when a drive voltage is supplied to an arbitrary one of the individual electrodes via a corresponding one of the electric wires, an electric field is generated in a portion of the piezoelectric layer that is located between the one individual electrode and the common electrode, so that that portion of the piezoelectric layer is deformed
Data Source
AI summary
An inkjet recording head, including a channel unit which has, along a reference plane, a plurality of pressure chambers communicating with a plurality of nozzles, respectively, each of which ejects a droplet of ink; and a piezoelectric actuator which changes a volume of an arbitrary one of the pressure chambers so that a corresponding one of the nozzles ejects the droplet of ink. The piezoelectric actuator includes a plurality of individual electrodes corresponding to the plurality of pressure chambers, respectively, a common electrode which is opposed to each of the individual electrodes, a piezoelectric layer which is interposed between the individual electrodes and the common electrode, and a plurality of electric wires which are connected to the plurality of individual electrodes, respectively, so as to supply respective drive voltages to the individual electrodes. A portion of at least one of the electric wires that is connected to at least one first individual electrode of the individual electrodes that corresponds to at least one first pressure chamber of the pressure chambers overlaps, as seen in a direction perpendicular to the reference plane, a portion of at least one second pressure chamber of the pressure chambers that differs from the at least one first pressure chamber.