Piezoelectric Pump F-Ratio Optimization for Ink Circulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing liquid ejection apparatuses with piezoelectric pumps inside the head face challenges in achieving effective circulation effects without increasing pump size, as the circulatory flow rate and pump size considerations are not adequately addressed in previous designs, leading to potential ink thickening and bubble accumulation issues.
Innovation Solution
A liquid ejection head design that includes an ejection port portion, a pressure chamber with an energy-generating element, a supply channel, a collecting channel, and a pump, where the F-ratio is maintained at 1.4 or less, optimizing the pump size by determining the minimum necessary circulatory flow rate and pump capacity, and utilizing a piezoelectric pump with a diaphragm and check valves to manage ink flow effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a piezoelectric pump is mounted inside the liquid ejection head to circulate ink, then the circulation effect is improved, but the device complexity and size increase
Solution Approach 1:
The pump chamber is integrated within the pressure chamber structure, combining the circulation function with the existing pressure control architecture. The diaphragm serves dual purposes as both a pump actuator and a pressure control element, merging multiple functions into a single integrated component structure.
Solution Approach 2:
The pump chamber is nested within the pressure chamber, with the diaphragm positioned inside the pressure chamber volume. The check valves are embedded within the pump chamber structure, creating a compact nested arrangement that maximizes space utilization and reduces overall head size.
2Volume of moving object
If the pump size is reduced to minimize head size, then the apparatus size is reduced, but the circulatory flow rate may be insufficient leading to ink thickening and bubble accumulation
Solution Approach 1:
The design optimizes the F-ratio parameter (ratio of ejection port width to pressure chamber height) to be 1.4 or less, which fundamentally changes the flow dynamics within the chamber. This parameter optimization allows enhanced circulation efficiency at reduced pump sizes by improving the flow path geometry and reducing dead zones where ink could stagnate.
Solution Approach 2:
The diaphragm provides dynamic volume change within the pump chamber, creating pulsating flow that enhances mixing and prevents stagnation. The check valves enable unidirectional flow control that maintains continuous circulation, adapting the flow pattern to operational conditions and preventing bubble accumulation through dynamic flow management.
3Productivity
If the F-ratio is reduced to 1.4 or less to optimize circulation, then the ink thickening and bubble accumulation are suppressed, but the manufacturing precision requirements increase
Solution Approach 1:
By establishing the F-ratio as a critical design parameter with a specific threshold (≤1.4), the invention provides a clear manufacturing target that balances performance and manufacturability. This quantitative parameter guideline enables manufacturers to achieve the desired circulation efficiency through controlled dimensional variations rather than requiring extreme precision across all dimensions.
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 achieves effective circulation and suppression of ink thickening and bubble accumulation, allowing for efficient ink ejection and reduced pump size, thereby minimizing the apparatus's overall size and cost while maintaining ejection performance.
Implementation Method 1
mounting a piezoelectric circulating pump (hereinafter also referred to simply as the 'piezoelectric pump') as a pump inside the head
Implementation Method 2
a pressure chamber that includes therein an energy-generating element configured to generate energy required to eject the liquid from the ejection port
Data Source
AI summary
A liquid ejection head including: an ejection port portion with an ejection port configured to eject liquid in an ejection direction; a pressure chamber that includes therein an energy-generating element to eject the liquid from the ejection port; a supply channel configured to supply the liquid to the pressure chamber; a collecting channel configured to collect the liquid from the pressure chamber; and a pump configured to cause the liquid in the collecting channel to flow into the supply channel, wherein Fratio is 1.4 or less.