Fluid Ejection Die Heat Exchangers for Thermal Management
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Solution Overview
Problem
The accumulation of waste heat due to the addition of fluid recirculation pumps in fluid ejection devices leads to thermal defects in the ejection of fluids, such as ink, causing issues like pigment settling and thermal defects during printing.
Innovation Solution
Incorporating heat exchangers thermally coupled to cooling channels within the moldable material of the fluid ejection die, which recirculates the fluid and uses a cooling fluid to transfer heat away from the heat exchangers, thereby reducing waste heat and thermal defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluid recirculation pumps are added to recirculate fluid within firing chambers, then pigment settling is reduced, but waste heat accumulates causing thermal defects
Solution Approach 1:
A heat exchanger is introduced as an intermediary component between the fluid recirculation system and the environment. The heat exchanger transfers waste heat from the recirculating fluid to a cooling medium, allowing the fluid recirculation pumps to continue operating (maintaining ejection consistency) while the heat exchanger handles the thermal management separately.
Solution Approach 2:
The waste heat generated by fluid recirculation pumps, which was previously causing thermal defects, is converted into a manageable thermal resource through the heat exchanger. The heat exchanger captures this waste heat and transfers it to a cooling medium, effectively converting the harmful thermal accumulation into a controlled heat transfer process that prevents thermal defects while maintaining the beneficial fluid recirculation.
2Temperature
If heat exchangers are added to remove waste heat, then thermal defects are reduced, but device complexity increases
Solution Approach 1:
The heat exchanger is integrated with the existing fluid channel structure, merging the thermal management function with the fluid delivery infrastructure. This combination allows waste heat removal capability to be added without proportionally increasing overall device complexity, as the heat exchanger utilizes the existing fluid pathways and structural framework.
Solution Approach 2:
The heat exchanger serves multiple functions: it removes waste heat from the recirculating fluid, provides thermal management for the firing chambers, and can potentially pre-condition incoming fluid. This multi-functionality justifies the added component by delivering multiple benefits from a single addition, reducing the net 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 solution effectively reduces thermal defects and pigment settling by efficiently dissipating heat generated by the fluid recirculation pumps, ensuring consistent and reliable fluid ejection during printing.
Implementation Method 1
a number of heat exchangers thermally coupled to a fluid channel side of the fluid ejection die... cooling channels defined in the moldable material thermally coupled to the heat exchangers... cooling fluid to transfer heat away from the heat exchangers
Implementation Method 2
cooling channels defined in the moldable material thermally coupled to the heat exchangers. The fluid recirculated by the fluid recirculation pumps within the firing chambers of the fluid ejection die is present within the cooling channels. The cooling fluid functioning to transfer heat from the heat exchangers
Data Source
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AI summary
A fluid ejection device may include a fluid ejection die embedded in a moldable material, a number of fluid recirculation pumps within the fluid ejection die to recirculate fluid within a number of firing chambers of the fluid ejection die, and a number of heat exchangers thermally coupled to a fluid channel side of the fluid ejection die.