Liquid Ejection Head Manifold Thermal Insulation Design
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Solution Overview
Problem
Existing liquid ejection heads face challenges in maintaining ink temperature consistency due to cooling effects in the supply channel leading to pressure chambers, resulting in discrepancies between detected and actual ink temperatures.
Innovation Solution
The design incorporates a supply manifold and a return manifold with a lower portion overlapping the supply manifold and standing portions at ends, creating an air layer and anti-cooling space to minimize exposure to open air, reducing thermal interaction and cooling effects, thereby maintaining ink temperature consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the thermistor is positioned immediately upstream of the pressure chamber to reduce temperature detection error, then the measurement precision improves, but the device complexity increases due to densely arranged components forcing the thermistor to be spaced apart
Solution Approach 1:
The patent positions the thermistor on the side wall of the pressure chamber rather than only at the upstream end, utilizing the lateral dimension to reduce detection error while maintaining compact component arrangement. This spatial reconfiguration allows accurate temperature measurement without increasing overall device complexity.
2Ease of manufacture
If the supply manifold is exposed to open air to simplify structure, then the ease of manufacture improves, but the temperature control stability deteriorates due to cooling effects on the liquid
Solution Approach 1:
The return manifold is positioned to overlap and cover the supply manifold, creating a nested configuration where the return manifold acts as a protective enclosure. This nested structure shields the supply manifold from open air exposure, reducing cooling effects while maintaining manufacturing simplicity.
Solution Approach 2:
The patent introduces air layers between the manifolds and surrounding structures as thermal insulation intermediaries. These air layers reduce heat transfer between the liquid and external environment, stabilizing liquid temperature without complicating the manifold structure.
3Stability of the object's composition
If the return manifold completely covers the supply manifold to maximize thermal protection, then the temperature stability improves, but the device complexity increases
Solution Approach 1:
The return manifold covers only the critical portions of the supply manifold where cooling effects are most significant, rather than providing complete coverage. This localized protection approach maintains temperature stability while avoiding unnecessary structural complexity.
Solution Approach 2:
The patent implements partial coverage of the supply manifold by the return manifold, providing sufficient thermal protection for the liquid without requiring complete enclosure. This partial action achieves adequate temperature stability with reduced device complexity.
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 effectively reduces the difference between detected and actual ink temperatures, enhancing the accuracy of temperature control for liquid ejection and reducing ejection failures by maintaining a more consistent ink temperature.
Implementation Method 1
A lower portion of the supply manifold is covered by the return manifold so as to be protected from an external space
Implementation Method 2
creating an air layer and anti-cooling space to minimize exposure to open air, reducing thermal interaction and cooling effects
Data Source
AI summary
A liquid ejection head includes a supply manifold, a return manifold, and individual channels each connected, at its upstream end, to the supply manifold and, at its downstream end, to the return manifold. Each of the individual channels communicates with a corresponding one of nozzles arranged in an array on a nozzle surface. The supply manifold and the return manifold extend in an extending direction along the nozzle array. The return manifold includes a lower portion located below the supply manifold to overlap the supply manifold in plan view orthogonal to the nozzle surface, and a standing portion located at at least one of opposite ends of the lower portion in the extending direction to be outside the supply manifold in plan view. The standing portion has a height to cover at least a portion of an end of the supply manifold when viewed in the extending direction.