Liquid Ejection Head Flow Path Asymmetry
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Solution Overview
Problem
Existing liquid ejection heads face challenges in efficiently managing fluid flow and pressure distribution within the pressurizing chambers, leading to issues such as fluid stagnation, clogging, and reduced printing quality due to uneven pressure propagation and flow resistance variations between individual and common flow paths.
Innovation Solution
The liquid ejection head incorporates a unique configuration of flow paths, including first, second, and third individual flow paths, and common flow paths, where the connection positions and orientations are optimized to enhance pressure distribution and fluid flow, reducing stagnation and clogging by increasing flow velocity and uniformity, and utilizing a piezoelectric actuator board to control the pressurizing chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two individual flow paths are used to connect the pressurizing chamber and the common flow path, then the liquid supply and collection functions are improved, but the flow resistance variation and pressure distribution uniformity deteriorate
Solution Approach 1:
The patent applies asymmetry by configuring the first and second flow paths with different connection positions to the fourth flow path. The first flow path connects at a first position while the second flow path connects at a second position that is offset in the direction perpendicular to the opening direction of ejection holes. This asymmetric arrangement balances the flow resistance between the two paths, ensuring uniform pressure distribution across the pressurizing chamber while maintaining efficient liquid supply and collection.
Solution Approach 2:
The patent introduces a spatial dimension by positioning the connection points of the first and second flow paths at different locations along the fourth flow path in the direction perpendicular to the opening direction of ejection holes. This dimensional separation allows independent optimization of flow resistance characteristics for each path, resolving the pressure distribution uniformity issue while preserving productivity.
2Reliability
If the connection positions of individual flow paths to the common flow path are optimized, then the pressure propagation consistency is improved, but the device complexity increases
Solution Approach 1:
The patent applies local quality by optimizing the connection positions of individual flow paths to the common flow path based on their specific functions. The first flow path connects at a position suitable for liquid supply, while the second flow path connects at a different position optimized for liquid collection. This localized optimization ensures consistent pressure propagation to each ejection unit without requiring complex global restructuring of the flow path system.
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 improves the reliability and quality of droplet ejection by minimizing fluid stagnation, reducing the risk of clogging, and maintaining consistent pressure propagation, resulting in enhanced printing performance and resolution.
Implementation Method 1
a pressurizing unit that pressurizes a liquid inside the plurality of pressurizing chambers
Data Source
AI summary
A liquid ejection head includes a plurality of pressurizing chambers connected to a plurality of ejection holes, a plurality of first individual flow paths connected to the plurality of pressurizing chambers, a plurality of second individual flow paths and a plurality of third individual flow paths, a first common flow path is connected in common to the plurality of first and plurality of second individual flow paths, and a second common flow path is connected in common to the plurality of third individual flow paths. The first and second individual flow paths are connected to the same pressurizing chamber, the first individual flow path is connected to the first common flow path in an opening end portion, compared to the second individual flow path. The first individual flow path is located opposite to a side where the ejection hole is open outward, compared to the second individual flow path.