Inkjet Ejection Head Diaphragm Structure for Meniscus Stability
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Solution Overview
Problem
Existing inkjet heads face challenges in achieving stable ejection characteristics due to meniscus overshoot and rising, which are exacerbated by high viscosity inks and increased droplet ejection demands, leading to instability in inkjet operations.
Innovation Solution
A liquid ejection head design featuring a diaphragm portion with a diaphragm wall that narrows the communication port width and increases flow path resistance, combined with a photosensitive resin protrusion to control meniscus rise and adhesive flow, ensuring stable ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the flow path resistance is reduced to enable faster ink replenishment, then the inkjet ejection speed increases, but the meniscus overshoot and rising phenomenon worsens, leading to unstable ejection characteristics
Solution Approach 1:
The flow path is designed with non-uniform cross-sectional area, creating different flow resistance characteristics at different locations. The communication port has a smaller cross-sectional area than the pressure chamber interior, generating localized high flow resistance at the entrance/exit region while maintaining larger flow area in the chamber. This local quality differentiation allows fast replenishment in the chamber while controlling meniscus rise at the communication port.
Solution Approach 2:
The flow path resistance is controlled by changing the geometric parameters of the communication port, specifically its cross-sectional area. By making the communication port narrower than the pressure chamber interior, the flow resistance parameter is increased at this critical location, which suppresses meniscus overshoot while still allowing adequate ink replenishment to the pressure chamber.
2Ease of manufacture
If the communication port width is increased to facilitate adhesive application, then the ease of manufacture improves, but the adhesive intrusion into the pressure chamber increases, affecting ejection stability
Solution Approach 1:
The communication port is designed with a narrower width at the adhesive application region compared to the pressure chamber interior. This local quality difference allows sufficient space for adhesive application and nozzle plate attachment while preventing excessive adhesive intrusion into the pressure chamber that would disrupt ink flow and meniscus stability.
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 design stabilizes ink ejection by quickly converging the meniscus and reducing adhesive intrusion, enhancing productivity and print quality by suppressing overshoot and improving ejection stability.
Implementation Method 1
a flow path resistance that is larger than the interior of the pressure chamber
Implementation Method 2
a diaphragm wall that blocks a portion of a communication port of the pressure chamber that communicates with a common chamber of the actuator unit
Data Source
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AI summary
According to one embodiment, a liquid ejection head includes an actuator unit, a nozzle plate, and a diaphragm portion. The actuator unit has grooves constituting a plurality of pressure chambers and a plurality of sidewalls formed between the grooves constituting the pressure chambers. The nozzle plate is disposed to face one side of the plurality of pressure chambers. The diaphragm portion has an diaphragm wall that blocks a portion of a communication port of the pressure chamber that communicates with a common chamber of the actuator unit and forms a diaphragm aperture that is decreased in width on the one side in a depth direction of the pressure chamber.