Piezoelectric Micro-Valve Sealing for Continuous Inkjet Nozzles
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Solution Overview
Problem
Conventional continuous inkjet printers face issues such as ink dripping, evaporation leading to maintenance requirements, and orifice plate degradation, which result in inefficiencies and increased costs.
Innovation Solution
A micro-valve design featuring a piezoelectric actuating beam with a sealing member, which creates a tight seal when not energized, preventing evaporation and reducing maintenance needs, and a jetting assembly with an interposer to prevent orifice plate bowing, ensuring precise fluid control and improved printing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a continuous inkjet system is used, then printing can be performed continuously, but ink evaporation occurs leading to maintenance requirements and fluid loss
Solution Approach 1:
The continuous inkjet stream is segmented into discrete droplets through periodic actuation of piezoelectric elements. This segmentation allows individual droplets to be controlled and directed, preventing the continuous stream from evaporating along its path while maintaining printing capability. The droplets are formed only when needed and immediately directed to the substrate.
Solution Approach 2:
The inkjet system uses periodic actuation of piezoelectric elements to create droplets at specific intervals rather than maintaining a continuous flow. This periodic action ensures that ink is only exposed to air for the minimal time required to form and eject a droplet, significantly reducing evaporation losses while maintaining continuous printing throughput.
2Productivity
If conventional inkjet orifice plates are used, then fluid can be jetted, but the orifice plates degrade requiring repair or replacement
Solution Approach 1:
The mechanical orifice plate system is replaced with a piezoelectrically actuated droplet generation system. Instead of relying on a physical orifice plate that degrades from fluid flow and contamination, the invention uses electrically actuated piezoelectric elements to form and eject droplets. This substitution eliminates the mechanical wear and degradation issues associated with traditional orifice plates while maintaining jetting capability.
Solution Approach 2:
The system changes the operating parameters from continuous high-velocity flow through fixed orifices to periodic low-velocity droplet ejection through piezoelectric actuation. This parameter change reduces the mechanical stress and degradation on the jetting surfaces, improving the durability and reliability of the system components.
3Quantity of substance
If makeup fluid is continuously replenished to compensate for evaporation, then fluid supply is maintained, but fluid loss and maintenance costs increase
Solution Approach 1:
The periodic droplet ejection system minimizes the time ink spends in the fluid path, reducing evaporation rates. This allows the system to maintain adequate fluid levels with minimal makeup fluid replenishment, as the ink is continuously moving and not standing in reservoirs where evaporation would be significant.
Solution Approach 2:
The system design incorporates features that minimize evaporation losses through controlled droplet formation and immediate ejection. By preventing evaporation through proper fluid management and rapid transit, the system reduces the need for external makeup fluid replenishment, making the fluid supply more self-sufficient.
4Device complexity
If ink is allowed to drip in undesired directions, then the system is simpler, but maintenance requirements increase
Solution Approach 1:
The continuous ink stream is segmented into discrete, controlled droplets through piezoelectric actuation. This segmentation allows precise control over droplet direction and placement, preventing unwanted dripping while maintaining system simplicity. Each droplet is formed and directed independently to the precise location required.
Solution Approach 2:
The system replaces complex mechanical drip control mechanisms with electrically actuated piezoelectric elements. This substitution provides more precise and reliable control over droplet ejection, eliminating unwanted dripping without requiring complex mechanical adjustment mechanisms, thereby reducing maintenance requirements.
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 micro-valve design enhances printing efficiency by minimizing evaporation and maintenance, allowing for faster drying inks and higher printing speeds, while the interposer maintains a proper seal, reducing clogs and improving droplet accuracy.
Implementation Method 1
The actuating beam comprises a layer of piezoelectric material and is movable between a closed position and an open position by applying an electrical signal to the layer of piezoelectric material
Data Source
AI summary
A micro-valve includes an orifice plate including a first surface and a second surface, and an orifice extending from the first surface to the second surface. The micro-valve also includes a spacing member disposed on the first surface and offset from the orifice, a valve seat disposed on the first surface. The valve seat defines an opening in fluid communication with the orifice in a flow direction. The micro-valve also includes an actuating beam disposed on the spacing member extending from the spacing member toward the orifice, the actuating beam being moveable between an open position and a closed position. The micro-valve also includes a sealing member affixed to an end portion of the actuating beam. In a closed position, a sealing surface of the sealing member contacts the valve seat to close the micro-valve.