Liquid Ejection Device Electrode Control for Ink Consistency
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Solution Overview
Problem
Existing liquid ejection devices with piezoelectric actuators face variations in ink ejection characteristics due to location-dependent thickness variations in the piezoelectric layers, leading to inconsistent performance among nozzles when driven with a single potential.
Innovation Solution
A liquid ejection device design featuring a piezoelectric actuator with overlapping pressure chambers and inspection spaces, where driving potentials are determined based on the resonance frequencies of dedicated inspection electrodes, allowing for individual control of nozzles and reducing device size by integrating inspection electrodes with driving electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single driving potential is applied to all electrodes in the piezoelectric actuator, then the device complexity is reduced, but variation in ink ejection characteristics occurs among nozzles due to location-dependent thickness variation in piezoelectric layers
Solution Approach 1:
The patent divides the electrode control system into multiple independent control groups, where each group corresponds to a specific region of the piezoelectric actuator. This segmentation allows different driving potentials to be applied to different regions, compensating for thickness variations in piezoelectric layers and ensuring consistent ink ejection characteristics across all nozzles.
Solution Approach 2:
The patent implements local quality control by measuring the thickness of piezoelectric layers at different locations and assigning specific driving potentials to corresponding electrode groups based on these measurements. This ensures that each region receives the appropriate electrical stimulus to achieve uniform ink ejection performance despite variations in piezoelectric layer thickness.
2Measurement precision
If multiple inspection electrode patterns are provided to detect location-dependent electrostatic capacitance variation, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent makes the inspection electrodes multi-functional by using them for both inspection purposes (measuring electrostatic capacitance to detect piezoelectric layer thickness variations) and as functional driving electrodes for ink ejection. This eliminates the need for separate inspection electrode patterns, reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The patent merges the inspection electrode function with the driving electrode function into a single integrated electrode system. The same electrodes used to apply driving potentials for ink ejection are also used to measure electrostatic capacitance and detect thickness variations, thereby reducing the number of components while achieving both inspection and actuation functions.
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 enables precise control of ink ejection characteristics among nozzles by applying tailored driving potentials, improving the consistency and quality of inkjet printing.
Implementation Method 1
a piezoelectric actuator provided with three piezoelectric layers arranged on the upper face of the cavity unit
Implementation Method 2
a piezoelectric actuator arranged on the passage unit and applying a pressure to liquid in the plurality of pressure chambers
Data Source
AI summary
Pressure applying sections applying a pressure to ink in pressure chambers are arranged in a staggered array in a sheet feed direction to form a row. Four of such rows of the pressure applying sections are aligned in the scanning direction. One part of inspecting sections among plural inspecting sections detecting resonance frequencies are arranged respectively at positions deviating from both end parts and an approximately center part, in the sheet feed direction, of each row of the pressure applying sections toward both sides in the scanning direction, and are aligned in the sheet feed direction. The other inspecting sections are arranged on both sides, in the sheet feed direction, of the rows of the pressure applying sections, and are aligned in the scanning direction. Further, plural dummy electrodes are aligned with the one part of inspecting sections, the inspection electrodes, and the pads in the sheet feed direction.