Piezoelectric Inkjet Head with Resistive Electrode Control
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Solution Overview
Problem
Existing liquid ejection heads, such as push mode type piezoelectric inkjet heads, experience reduced ink ejection speed and volume when adjacent nozzles are driven simultaneously, leading to dot misalignment and density unevenness due to reaction forces on support piezoelectric poles.
Innovation Solution
The liquid ejection head incorporates a configuration with individual electrodes on piezoelectric bodies, a nozzle plate with nozzles, switching elements, and electric resistances between adjacent individual electrodes, allowing for controlled voltage application and reduced current flow during single nozzle driving, thereby equalizing pressure generation in single and multi-nozzle simultaneous driving modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If adjacent nozzles are driven simultaneously, then productivity is improved, but ink ejection speed and volume decrease due to support piezoelectric pole deformation
Solution Approach 1:
The actuator is segmented into drive piezoelectric poles and support piezoelectric poles, with independent electrode connections. This allows selective electrical connection of support poles during multi-nozzle driving to prevent their deformation while maintaining their structural support function, thereby resolving the contradiction between multi-nozzle productivity and ink ejection speed
Solution Approach 2:
The electrical connection state of support piezoelectric poles is dynamically changed based on driving mode. During single-nozzle driving, support poles are electrically connected to prevent deformation. During multi-nozzle driving, support poles are electrically disconnected to allow deformation compensation, thus maintaining ink ejection speed while enabling high productivity
2Productivity
If adjacent nozzles are driven simultaneously, then productivity is improved, but manufacturing precision deteriorates due to dot misalignment and density unevenness
Solution Approach 1:
By segmenting the actuator into drive and support piezoelectric poles with independent electrical control, the invention enables precise compensation of support pole deformation during multi-nozzle driving. This maintains consistent ink ejection characteristics across different driving modes, eliminating dot misalignment and density unevenness while preserving high productivity
Solution Approach 2:
The invention implements electrical feedback control where the connection state of support piezoelectric pole electrodes is adjusted based on the driving mode. This feedback mechanism ensures that support poles do not deform during multi-nozzle driving, maintaining precise dot placement and uniform density across the print output
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 configuration effectively eliminates dot misalignment and density unevenness by ensuring consistent ink ejection pressure across different driving modes, enhancing printing quality.
Implementation Method 1
The actuator includes a plurality of piezoelectric bodies that change volumes of the pressure chambers according to a drive signal
Implementation Method 2
The electric resistances electrically connect the individual electrodes of the piezoelectric bodies adjacent to each other
Data Source
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AI summary
Provided are a liquid ejection head and a liquid ejection apparatus capable of eliminating dot misalignment or density unevenness due to a drive pattern. A liquid ejection head according to an embodiment includes a plurality of pressure chambers, an actuator, a plurality of individual electrodes, a nozzle plate, a plurality of switching elements, and a plurality of electric resistances. The actuator includes a plurality of piezoelectric bodies that change volumes of the pressure chambers according to a drive signal. The plurality of individual electrodes are respectively provided on the plurality of piezoelectric bodies. The nozzle plate has a plurality of nozzles communicating with the plurality of pressure chambers, respectively. The switching element selectively connects the drive signal for the piezoelectric body. The switching elements are electrically connected to the plurality of individual electrodes. The electric resistances electrically connect the individual electrodes of the piezoelectric bodies adjacent to each other.