Fluid Ejection Head Thermal Regulation via Metal Insert
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for heating or cooling thermally sensitive fluids in fluid ejection devices risk compromising the integrity of the fluids due to direct exposure to high heat flux, leading to inconsistent jetting performance and temperature fluctuations.
Innovation Solution
A fluid cartridge design incorporating a metal insert with thermal contact extensions and a heating element, which allows for controlled heating or cooling of the fluid without direct exposure to high heat flux, using thermoelectric devices and heat transfer protrusions to maintain optimal pre-jetting temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heating element is placed directly into the main fluid reservoir to heat the bulk fluid, then the fluid can be heated to optimal temperature, but the direct and prolonged exposure to high heat flux compromises the integrity of temperature sensitive fluids
Solution Approach 1:
The patent divides the fluid reservoir into two distinct zones: a bulk fluid reservoir for storage and a separate pre-heating chamber for temperature adjustment. This segmentation allows the heating element to operate in isolation within the pre-heating chamber, preventing direct contact with the bulk fluid and eliminating the harmful effect of prolonged high heat flux exposure while still achieving the desired temperature control for jetting operations.
Solution Approach 2:
The patent introduces an intermediary structure (the pre-heating chamber with thermal management features) between the heating element and the bulk fluid. This intermediary allows thermal energy to be transferred to the fluid without requiring direct exposure to the heating element, thereby mediating the thermal interaction to protect temperature-sensitive fluids from degradation while still achieving effective heating.
2Temperature
If the cartridge is removed from refrigeration and heated using conventional methods, then the fluid reaches optimal operating temperature, but extended times at elevated temperatures compromise the integrity of temperature sensitive fluids
Solution Approach 1:
The patent implements preliminary thermal conditioning by providing thermal insulation and reflective barriers in the pre-heating chamber before the fluid undergoes temperature adjustment. This preliminary setup minimizes heat loss and ensures rapid, controlled heating to the target temperature, reducing the total time the fluid spends at elevated temperatures and thereby preserving fluid integrity.
Solution Approach 2:
The patent employs high-performance insulation materials and reflective surfaces to accelerate the heating process, allowing the fluid to quickly reach the optimal operating temperature and then be rapidly transferred to the jetting chamber. This rushed thermal transition minimizes the dwell time at elevated temperatures, preventing degradation of temperature-sensitive fluids.
3Productivity
If thermal energy is coupled into the fluid at high frequencies, then jetting performance is improved, but heat may not be removed from the ejection head chip quickly enough to maintain the optimum dispense temperature
Solution Approach 1:
The patent introduces a thermal management intermediary system comprising insulation layers and reflective barriers positioned between the heating element and the ejection head chip. This intermediary system allows rapid thermal energy coupling for high-frequency jetting while simultaneously preventing excessive heat accumulation, thereby maintaining optimal dispense temperature control even at high operating frequencies.
Solution Approach 2:
The patent employs thermally conductive materials with specific thermal properties in the pre-heating chamber and insulation materials with varying thermal resistances to optimize heat transfer rates. By carefully selecting and positioning materials with different thermal parameters, the system enables rapid heating for high-frequency operation while preventing overheating at the ejection head chip.
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 ensures consistent and efficient temperature regulation of thermally sensitive fluids, maintaining steady-state jetting temperatures and preventing fluid degradation, thereby enhancing the reliability and performance of fluid ejection.
Implementation Method 1
a heating element embedded in the metal insert... The metal insert is heated using the heat transfer device to adjust a temperature of the fluid
Implementation Method 2
Some embodiments incorporate a Peltier element into the metal insert
Implementation Method 3
one or more thermal contact extensions... The one or more thermal contact extensions may be configured to be in thermal contact with a thermoelectric device
Data Source
AI summary
A fluid cartridge and method for heating or cooling fluid in the fluid cartridge. The fluid cartridge includes a cartridge body containing the fluid and has a bottom wall having a fluid supply opening therein. A metal insert is adhesively fastened to the bottom wall of the cartridge body. The metal insert has a fluid supply slot therein corresponding to the fluid supply opening in the bottom wall, a die bond surface adjacent to the fluid supply slot configured for adhesively fastening an ejection head chip thereto, and a heat transfer device selected from a heating element embedded in the metal insert and one or more thermal contact extensions. An ejection head chip is adhesively fastened to the die bond surface of the metal insert.