Thermal Bend Actuator with Insulation Beam for Inkjet Nozzle
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Solution Overview
Problem
Existing thermal bend inkjet nozzles face challenges in achieving efficient drop ejection and mechanical robustness, with previous designs either suffering from high viscous resistance due to paddle design or losing structural rigidity by spacing active and passive beams apart.
Innovation Solution
A thermal bend actuator with a plurality of cantilever beams, where the active beam is comprised of an aluminium alloy and spaced apart from a passive beam, optionally with a tortuous configuration and a third insulation beam, to maximize thermoelastic efficiency and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the active beam is spaced apart from the passive beam, then thermal losses are minimized and drop ejection efficiency is improved, but structural rigidity is lost
Solution Approach 1:
A third insulation beam is introduced as an intermediary element positioned between the active beam and passive beam. This insulation beam serves as a thermal barrier that reduces heat transfer from the active beam to the passive beam, thereby minimizing thermal losses while maintaining the structural integrity and rigidity of the actuator assembly.
Solution Approach 2:
The actuator employs a composite structure consisting of three distinct beams: an active beam, a passive beam, and an intermediate insulation beam. This composite design combines materials with different thermal and mechanical properties to achieve both thermal isolation (reducing energy loss) and structural rigidity, resolving the contradiction between heat isolation and mechanical strength.
2Device complexity
If a paddle is used to eject ink, then the nozzle construction is simple, but viscous resistance is high and drop ejection efficiency is reduced
Solution Approach 1:
The paddle component is completely removed from the nozzle design. Instead of using a paddle to push the ink drop, the invention relies on direct thermal actuation of the ink meniscus through the nozzle opening, eliminating the intermediate mechanical component that caused high viscous resistance.
Solution Approach 2:
The mechanical paddle-based ink ejection system is replaced with a direct thermal field approach. The active beam generates thermal energy that directly acts on the ink meniscus, substituting mechanical contact with thermal field interaction to reduce viscous resistance and improve ejection efficiency.
3Productivity
If the active beam has high thermal expansion, then drop ejection efficiency is improved, but thermal losses to the passive beam increase
Solution Approach 1:
The insulation beam acts as a thermal intermediary that blocks heat transfer from the active beam to the passive beam. This allows the active beam to maintain high thermal expansion for efficient drop ejection while preventing thermal energy from being lost to the passive beam through conduction.
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 enhances drop ejection efficiency and mechanical robustness by minimizing thermal losses and maintaining structural integrity, allowing for improved power availability and control over drop flight direction while reducing adverse effects on nozzle spacing.
Implementation Method 1
when a current is passed through the first beam, the first beam expands relative to the second beam, resulting in bending of the actuator
Implementation Method 2
when a current is passed through the first beam, the first beam expands relative to the second beam
Implementation Method 3
Thermal bend actuation generally means bend movement generated by thermal expansion of one material, having a current passing therethough, relative to another material
Data Source
AI summary
An inkjet nozzle assembly includes a nozzle chamber having a floor and a roof, wherein moving portion of the roof is moveable towards the floor for ejection of ink. A thermal bend actuator defines part of the moving portion of the roof, and an active beam of the actuator defines an upper layer of the moving portion.