Piezoelectric Liquid Ejection Head Layout for Thickened Ink Flow
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Solution Overview
Problem
Existing liquid ejection heads face issues with thickened ink accumulation due to reduced flow rates in areas with increased cross-sectional areas, leading to insufficient removal of thickened ink, especially in configurations where the nozzle is directly below the pressure chamber.
Innovation Solution
A liquid ejection head design with a stacked configuration of piezoelectric elements, vibration plates, and pressure chamber substrates, including partitioned pressure chambers and common flow paths, which reduces cross-sectional areas and enhances ink flow by using absorption chambers to minimize pressure escape and improve ejection characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the nozzle is disposed directly below the pressure chamber to transmit pressure without loss, then ejection characteristics are improved, but the cross-sectional area of the flow path is locally increased causing decreased flow rate and insufficient removal of thickened ink
Solution Approach 1:
The pressure chamber substrate is divided into multiple separate portions (first portion, second portion, third portion) that are positioned at different locations. These portions create multiple separate flow paths through the substrate, preventing the formation of a large continuous space directly above the nozzle. This segmentation maintains high flow rates while still allowing effective pressure transmission to the nozzle for good ejection characteristics.
2Productivity
If the cross-sectional area of the pressure chamber is reduced to increase flow rate, then thickened ink removal is improved, but pressure transmission efficiency may be compromised
Solution Approach 1:
The pressure chamber substrate portions are strategically positioned to create different flow path characteristics in different regions. The first and second portions create restricted flow paths with smaller cross-sectional areas to maintain high flow rates and remove thickened ink. Meanwhile, the third portion positioned between them provides pressure distribution functionality. This local differentiation of substrate structure achieves both high flow rate and effective pressure transmission without compromising either property.
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
The design effectively prevents thickened ink accumulation by maintaining efficient ink flow rates and improving ejection reliability through optimized pressure transmission and absorption, ensuring superior ejection performance.
Implementation Method 1
a liquid such as ink is ejected from a nozzle communicating with a pressure chamber as a piezoelectric element changes a pressure in the pressure chamber
Implementation Method 2
a vibration plate that vibrates through driving of the piezoelectric element
Implementation Method 3
the thickened ink is caused as a viscosity of the ink increases directly above the nozzle because of reduction in a solvent component due to evaporation at a gas-liquid interface of the nozzle
Data Source
AI summary
the first pressure chamber substrate is provided with a first pressure chamber partitioned by the first portion, the third portion, and the fourth portion, and a second pressure chamber partitioned by the second portion, the third portion, and the fifth portion, the second pressure chamber substrate is provided with a third pressure chamber partitioned by the third portion, the fourth portion, the fifth portion and communicating with the first pressure chamber, the second pressure chamber, and a nozzle, and the piezoelectric element is commonly disposed across the first pressure chamber, the second pressure chamber, and the third pressure chamber.