Liquid Ejecting Head Throttle Units for Meniscus Swelling
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Solution Overview
Problem
Inkjet heads face challenges in increasing speed and stability due to meniscus swelling and overshooting, which affects ejection characteristics, especially when ejecting high-viscosity inks or large droplets, as existing designs struggle to rapidly reduce meniscus swelling for stable next ejection events.
Innovation Solution
A side shooter type liquid ejecting head with throttle units at the end portions of pressure chambers, where the cross-sectional area is smaller than inside, increasing fluid resistance and reducing meniscus swelling by configuring protrusions and deformable side walls to manage ink flow effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the fluid resistance in the flow path from the common liquid chamber to the nozzle is decreased, then the speed of ink ejection is improved, but the amount of overshooting and meniscus swelling increases
Solution Approach 1:
The flow path is segmented into multiple sections with different resistance characteristics. The throttle unit creates a high-resistance section at the end portion of the pressure chamber, while the main flow path maintains lower resistance. This segmentation allows the system to achieve both fast ink ejection (through the low-resistance main path) and reduced meniscus swelling (through the high-resistance throttle section that prevents excessive flow during ejection).
Solution Approach 2:
The throttle unit acts as an intermediary element between the common liquid chamber and the nozzle. It mediates the fluid flow by introducing a controlled resistance that prevents excessive overshooting while maintaining sufficient flow rate for high-speed ejection. The throttle unit is positioned at the end portion of the pressure chamber to specifically control the flow dynamics during the ejection process.
2Productivity
If the speed of the ink jet head is increased, then the productivity is improved, but the meniscus swelling occurs more severely affecting ejection characteristics
Solution Approach 1:
The throttle unit is pre-configured at the end portion of the pressure chamber to prevent meniscus swelling before it can affect the next ejection event. By having the throttle unit in place beforehand, the system can rapidly reduce swelling during high-speed operation without waiting for the meniscus to stabilize, thus maintaining reliable ejection characteristics even at increased productivity levels.
3Stability of the object's composition
If the cross-sectional area of the end portions of pressure chambers is reduced, then the fluid resistance increases and meniscus swelling is reduced, but the device complexity increases
Solution Approach 1:
The throttle unit applies local quality change by creating a high-resistance section only at the end portion of the pressure chamber, while the main flow path maintains its original cross-sectional area. This localized modification allows the system to increase fluid resistance where needed (at the end portion) to reduce meniscus swelling, without compromising the overall flow rate or adding complexity to the entire pressure chamber structure.
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 provides stable ejection characteristics by reducing meniscus swelling and improving the speed of inkjet heads, ensuring quicker meniscus return and enhanced ejection stability, even at higher frequencies, thus improving printing quality and efficiency.
Implementation Method 1
The actuator includes a plurality of grooves that form the pressure and dummy chambers and a plurality of side walls that surround the grooves. The side walls of the pressure chambers deform upon application of a drive signal.
Implementation Method 2
the actuator comprises a piezoelectric material
Implementation Method 3
The throttle unit is configured in such a way that the fluid resistance increases at the end portion in comparison with the inside of the pressure chamber. In other words, the end portions have a cross-sectional area smaller than that of the full dimension of the inside of the pressure chamber thereby increasing the fluid resistance at the end portions.
Data Source
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AI summary
A liquid ejecting head of a side shooter type (10) includes a plate (12) including a plurality of nozzles arranged along a first direction and an actuator (22) with a plurality of pressure chambers (31) arranged along the first direction. Each pressure chamber communicates with a corresponding one of the nozzles. The actuator further includes dummy chambers (32), each of which is between two otherwise adjacent pressure chambers. Common chambers are provided in the actuator. The pressure and dummy chambers are arranged between the common chambers. The end portions of the pressure chambers are connected to a common chamber. The width of the end portions of each of the pressure chambers is less than the width of a portion of the pressure chamber between the end portions.