Liquid Ejection Head Thermal Management via Insulating Members
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Solution Overview
Problem
In liquid ejection heads, non-uniform temperature distributions across recording element substrates lead to varying ink viscosity and ejection amounts, causing uneven print density and degraded image quality, particularly in line-type heads used for high-speed printing.
Innovation Solution
A liquid ejection head design featuring recording element substrates with energy generating elements, supported by temperature equalizing members with high thermal conductivity and heat insulating members with lower thermal conductivity, which helps to distribute heat evenly across the substrate, reducing temperature non-uniformity and maintaining consistent ink viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a line-type head with multiple energy generating elements is used for high-speed printing, then productivity is improved, but temperature non-uniformity increases causing print density unevenness
Solution Approach 1:
A heat insulating member is introduced as an intermediary component between the heat-generating recording element substrates and the base substrate. This mediator prevents excessive heat transfer to the base substrate while maintaining thermal isolation between adjacent recording element substrates, thereby preserving print density uniformity during high-speed continuous operation
Solution Approach 2:
The thermal management system is segmented by providing individual heat insulating members for each recording element substrate. This segmentation allows independent thermal control of each substrate, preventing heat from continuously operated elements from affecting adjacent elements, thus maintaining uniform print density across all nozzles
2Manufacturing precision
If heat insulating members are placed between recording element substrates and base substrate, then temperature uniformity is improved, but device complexity increases
Solution Approach 1:
The heat insulating member serves multiple functions simultaneously: it provides thermal insulation between the recording element substrate and base substrate, acts as a mechanical support structure, and facilitates modular assembly. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in 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
The design effectively reduces temperature non-uniformity and maintains consistent ink viscosity, improving print density uniformity and overall image quality by ensuring uniform heat distribution across the recording element substrates.
Implementation Method 1
a heat insulating member disposed between the flow passages and the base substrate
Implementation Method 2
a thermal conductivity of the support members is equal to or greater than a thermal conductivity of the recording element substrates
Data Source
AI summary
A liquid ejection head includes a plurality of recording element substrates that each include an energy generating element generating energy utilized for ejecting a liquid and that each have a supply port through which the liquid is supplied to the energy generating element, a plurality of support members that each have a flow passage communicating with a corresponding one of the supply ports and that each support a corresponding one of the plurality of recording element substrates, a base substrate that supports the plurality of support members, and a heat insulating member disposed between the flow passages and the base substrate. In the liquid ejection head, a thermal conductivity of the support members is equal to or greater than a thermal conductivity of the recording element substrates, and a thermal conductivity of the heat insulating member is less than a thermal conductivity of the base substrate.