Thermoelastic Inkjet Actuator Beam Design for Viscous Resistance
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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 ink resistance or structural rigidity issues.
Innovation Solution
A thermal bend actuator with a plurality of cantilever beams, where the first active beam is connected to drive circuitry and the second passive beam is mechanically cooperative, allowing for efficient bending when a current is passed through, with the active beam defining at least part of the exterior surface and optionally being an aluminium alloy, and the passive beam being porous silicon dioxide, to enhance thermal efficiency and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the actuator is positioned externally of the nozzle chamber with a paddle, then the construction is simple, but both faces of the paddle work against viscous ink causing high resistance
Solution Approach 1:
The actuator is merged with the nozzle chamber roof structure, where the active beam becomes part of the roof itself. This integration eliminates the separate paddle component and reduces the surfaces working against viscous ink, while maintaining construction simplicity through the unified structure.
Solution Approach 2:
The active beam serves multiple functions: it acts as both the thermal bend actuator element and part of the nozzle chamber roof structure. This multi-functionality reduces the number of separate components needed while addressing the viscous resistance issue by minimizing paddle surface area.
2Power
If the active and passive beams are spaced apart, then thermal bend efficiency is maximized, but structural rigidity is lost
Solution Approach 1:
An insulating beam is introduced as an intermediary element between the active and passive beams. This mediator maintains the thermal insulation needed for efficient bend actuation while providing structural connection that preserves the overall rigidity of the nozzle chamber roof assembly.
Solution Approach 2:
The actuator structure uses composite construction with different material properties - the active beam, passive beam, and insulating beam are made from materials selected to optimize both thermal performance (for bend efficiency) and mechanical performance (for structural rigidity).
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 design improves drop ejection efficiency and mechanical robustness by minimizing thermal losses and maximizing structural integrity, allowing for effective ink ejection with reduced energy requirements and improved control over drop flight direction.
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
the first beam expands relative to the second beam, resulting in bending of the actuator
Implementation Method 3
the passive beam being porous silicon dioxide, to enhance thermal efficiency and structural integrity
Data Source
AI summary
An inkjet nozzle assembly comprises a nozzle chamber having a floor and a roof, the roof having a nozzle opening defined therein. A moving portion defines part of the roof so that the moving portion is moveable towards the floor. A thermal actuator defines part of the moving portion. The thermal actuator comprises a first active beam for connection to drive circuitry and a second passive beam mechanically cooperating with the first beam, such that when a current is passed through the first beam, the first beam expands relative to the second beam resulting in bending of the actuator. The first active beam is disposed on an upper surface of the passive beam relative to the floor.