Piezoelectric Liquid Ejecting Head for Residual Vibration Sensing
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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 incorporating 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 same piezoelectric element and pressure chamber are shared for both liquid ejection and residual vibration detection, then device complexity is reduced, but driving frequency is limited and throughput is insufficient
Solution Approach 1:
The piezoelectric element is segmented into two separate elements: a first piezoelectric element for liquid ejection and a second piezoelectric element for residual vibration detection. This segmentation allows independent operation of ejection and detection functions, enabling real-time detection without limiting the driving frequency for ejection, thereby increasing throughput.
Solution Approach 2:
The detection function is extracted from the ejection system by providing a separate second piezoelectric element dedicated to residual vibration detection. This extraction allows the detection operation to be performed independently from the ejection operation, removing the constraint that previously limited driving frequency and throughput.
2Measurement precision
If the neutral axis position of the second piezoelectric element is positioned above the neutral axis of the first piezoelectric element, then detection precision is improved, but structural complexity increases
Solution Approach 1:
The second piezoelectric element is designed with an asymmetric structure relative to the first piezoelectric element, specifically positioning its neutral axis above the neutral axis of the first element. This asymmetric positioning optimizes the detection of residual vibrations by aligning the sensing axis with the vibration mode, thereby improving detection precision while maintaining manageable structural complexity.
Solution Approach 2:
The neutral axis position of the second piezoelectric element is locally optimized to be above that of the first element, creating a specialized detection zone that is optimally positioned to sense residual vibrations. This local quality adjustment enhances detection precision without requiring complete redesign of the overall structure.
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 efficiency and effectiveness.
Implementation Method 1
a first piezoelectric element to apply a pressure for ejecting a liquid from a nozzle when the first piezoelectric element is driven
Implementation Method 2
a second piezoelectric element to detect a residual vibration of the pressure applied in the pressure chamber
Data Source
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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 above a neutral axis of the first piezoelectric element.