Liquid Ejecting Head Layout for Residual Vibration Detection
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Solution Overview
Problem
Existing liquid ejecting heads face limitations in driving frequency due to real-time detection of residual vibrations, leading to insufficient throughput, and the sharing of piezoelectric elements for both ejection and detection results in inadequate structural examination.
Innovation Solution
A liquid ejecting head design featuring separate first and second piezoelectric elements for pressure application and residual vibration detection, respectively, with distinct neutral axes and varying thickness ratios of piezoelectric bodies and insulating layers to optimize performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the piezoelectric element and pressure chamber are shared for both ejection and detection, then the device complexity is reduced, but the driving frequency is limited and throughput is insufficient
Solution Approach 1:
The patent divides the single piezoelectric element into two separate piezoelectric elements: a first piezoelectric element for ejection and a second piezoelectric element for detection. This segmentation allows independent operation of ejection and detection functions, enabling higher driving frequencies and improved throughput while maintaining manageable device complexity through modular design.
Solution Approach 2:
The patent implements multi-functionality by having the first piezoelectric element serve both as an actuator for ejection and as a sensor for detecting liquid level changes, while the second piezoelectric element dedicatedly detects residual vibrations. This allows the system to perform multiple functions with optimized components, resolving the contradiction between structural simplicity and productivity.
2Device complexity
If the piezoelectric element is used for both ejection and detection, then the device complexity is reduced, but the driving frequency for ejecting is limited
Solution Approach 1:
By segmenting the piezoelectric element into two separate elements with distinct neutral axes, the patent enables the first piezoelectric element to operate at higher driving frequencies for ejection while the second piezoelectric element independently detects residual vibrations. This segmentation eliminates the frequency limitation imposed by shared functionality.
Solution Approach 2:
The patent applies local quality by optimizing each piezoelectric element's structure according to its specific function: the first piezoelectric element is designed for high-frequency ejection actuation, while the second piezoelectric element is configured for precise vibration detection. This functional differentiation allows each component to operate at its optimal frequency range.
3Productivity
If separate piezoelectric elements are provided for ejection and detection, then the driving frequency is improved, but the structure becomes more complex
Solution Approach 1:
The patent merges the two piezoelectric elements into a single integrated assembly where the first piezoelectric element for ejection and the second piezoelectric element for detection are positioned adjacent to each other with their neutral axes at different heights. This merging approach maintains compact structure while enabling independent high-frequency operation of both functions.
Solution Approach 2:
The patent resolves the complexity increase by utilizing the vertical dimension, positioning the neutral axis of the second piezoelectric element at a different height than the first piezoelectric element. This spatial arrangement in another dimension allows both elements to coexist without interfering with each other, maintaining compactness while enabling separate high-frequency operations.
4Measurement precision
If the neutral axis of the second piezoelectric element is positioned below the neutral axis of the first piezoelectric element, then the detection accuracy is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by deliberately setting the neutral axis of the second piezoelectric element at a different height than the first piezoelectric element. This parameter differentiation optimizes the detection accuracy for residual vibrations while the patent provides guidance on acceptable tolerance ranges to manage manufacturing precision requirements.
Solution Approach 2:
The patent uses copying by creating a second piezoelectric element that replicates the structure and function of the first piezoelectric element, but with the neutral axis positioned at a different height. This copying approach with modified parameters allows for optimized detection performance while maintaining manufacturing processes that are extensions of the original design.
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
Enhances driving frequency and throughput by allowing independent operation of ejection and detection functions, improving structural integrity and efficiency.
Implementation Method 1
a first piezoelectric element, and a detection chamber in which a second piezoelectric element detects a residual vibration of a pressure of liquid applied in the pressure chamber
Data Source
AI summary
A liquid ejecting head includes a pressure chamber that applies a pressure of a liquid for ejecting a liquid from a nozzle when a first piezoelectric element is driven, and a detection chamber in which a second piezoelectric element detects a residual vibration of the pressure of the liquid applied in the pressure chamber. The first piezoelectric element includes a first piezoelectric body, a first upper electrode, a first lower electrode, and a first vibration plate provided below the first lower electrode, the second piezoelectric element includes a second piezoelectric body, a second upper electrode, a second lower electrode, and a second vibration plate provided below the second lower electrode, and a neutral axis of the second piezoelectric element is positioned below a neutral axis of the first piezoelectric element.