Liquid Ejecting Device Viscosity Control for Pseudoplastic Fluids
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Solution Overview
Problem
Existing liquid ejecting devices face challenges in efficiently managing the flow rate and viscosity of pseudoplastic liquids, leading to issues such as pressure wave propagation and fluid crosstalk.
Innovation Solution
The device incorporates a flow path member with a specific configuration that includes supply and collection reservoirs, manifolds, flow paths, pressure chambers, and nozzles, along with a flow rate setting unit that adjusts the circulation flow rate to achieve a target flow rate, ensuring the average viscosity in supply flow paths is less than or equal to half that in supply manifolds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the circulation flow rate is increased to improve liquid supply stability, then the viscosity control becomes more difficult and pressure wave propagation increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the circulation flow rate to a specific range (0.5-5 mL/min) and maintaining the average viscosity ratio between supply flow paths and supply manifolds at ≤0.5. This parameter optimization resolves the contradiction by finding the optimal flow rate that ensures liquid supply stability while minimizing pressure wave propagation through appropriate viscosity management.
2Ease of operation
If the average viscosity in supply flow paths is reduced to improve droplet ejection smoothness, then the liquid supply stability may be compromised
Solution Approach 1:
The patent resolves this contradiction by establishing an optimal viscosity parameter range where the average viscosity in supply flow paths is maintained at ≤0.5 times that in supply manifolds. This specific parameter relationship ensures that the liquid flows smoothly for easy droplet ejection while maintaining sufficient viscosity for stable liquid supply through the circulation system.
3Device complexity
If the flow path configuration is simplified to reduce device complexity, then the viscosity control precision and flow rate management become insufficient
Solution Approach 1:
The patent applies segmentation by dividing the flow path into distinct functional segments: supply reservoir, supply manifolds, supply flow paths, pressure chambers, collection flow paths, collection manifolds, and collection reservoir. This segmentation allows independent control and optimization of viscosity and flow rate in each segment, achieving precise viscosity control (average viscosity ratio ≤0.5) while maintaining manageable device complexity through modular design.
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 configuration allows for stable and efficient liquid supply, reduces pressure wave propagation and fluid crosstalk, and ensures smooth droplet ejection by maintaining optimal viscosity and flow rate conditions.
Implementation Method 1
a pseudoplastic liquid whose viscosity is from 0.02 Pa·s to 0.4 Pa·s at a shear rate of 1000 s−1 and whose viscosity is from 0.5 Pa·s to 50 Pa·s at a shear rate of 0.01 s−1
Data Source
AI summary
A liquid ejecting device includes a flow path member, an actuator, a pump, and a controller. The flow path member includes a flow path configured to direct flow of a pseudoplastic liquid through the flow path member. The actuator is configured to cause droplets to be ejected. The pump is configured to cause the liquid to flow sequentially through a supply reservoir, a plurality of supply manifolds, a plurality of supply flow paths, and a plurality of pressure chambers. The controller is configured to adjust a flow rate of the liquid to a prescribed target flow rate. The flow path has a flow path shape in which an average viscosity of the liquid in the plurality of supply flow paths is less than or equal to half an average viscosity of the liquid in the plurality of supply manifolds when the flow rate is equal to the target flow rate.