Self-Priming Fluid Reservoir with Backpressure Foam
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Solution Overview
Problem
Existing fluid reservoirs for inkjet printers in the life sciences face challenges with self-priming and maintaining consistent fluid flow, especially when not prefilled, leading to issues like air trapping and fluid drooling, which are costly and inefficient, particularly in medical assays where precise reagent ratios are crucial.
Innovation Solution
A self-priming fluid reservoir system with a flow-inducing pump, such as a deformable bladder or spring-loaded bladder, and a backpressure device like fluid-permeable foam, integrated with a fluid outlet and pressure relief valve, allows for on-site filling and ensures consistent fluid delivery to the ejection head, reducing waste and extending the life of ejection head chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fluid reservoirs are not prefilled to enable on-site filling, then cost and efficiency are improved, but self-priming capability deteriorates leading to air trapping and inconsistent fluid flow
Solution Approach 1:
A priming port is provided that allows the fluid reservoir to be primed before use. This preliminary action enables the reservoir to establish proper fluid flow and remove air bubbles before the actual dispensing operation begins, thereby maintaining self-priming capability while allowing on-site filling.
Solution Approach 2:
The priming port serves as an intermediary mechanism between the fluid reservoir and the external environment. It provides a dedicated pathway for introducing fluid and removing air, mediating the transition from an empty/unprimed state to a properly filled and primed state without compromising the reservoir's ability to maintain consistent flow during operation.
2Loss of substance
If fluid reservoirs are designed for on-site filling, then packaging and shipping costs are reduced, but fluid flow consistency worsens due to air trapping
Solution Approach 1:
The priming port enables preliminary priming action that removes air bubbles and establishes consistent fluid flow before dispensing begins. This preliminary action ensures that even though the reservoir is filled on-site, the fluid flow composition remains stable and consistent during actual use.
3Quantity of substance
If the fluid chamber in the ejection head is made larger to hold more fluid, then fluid delivery consistency improves, but the risk of fluid drooling increases
Solution Approach 1:
A backpressure device is provided that creates resistance to fluid flow in the opposite direction. This backpressure provides feedback control on the fluid delivery system, preventing excessive pressure buildup that could cause drooling, while still allowing sufficient fluid to be delivered to the ejection head for consistent operation.
4Manufacturing precision
If a backpressure device is added to prevent fluid drooling, then fluid delivery precision improves, but device complexity increases
Solution Approach 1:
A porous backpressure device is provided that uses a porous structure to create fluid resistance. The porous material provides backpressure in a simple, passive manner without requiring complex active control mechanisms, thereby improving fluid delivery precision while minimizing the increase in device complexity.
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 solution enables cost-effective, on-site filling of fluid reservoirs, reduces packaging and shipping costs, minimizes air trapping and fluid wastage, and maintains precise fluid delivery, addressing the limitations of traditional prefilled cartridges by allowing perishable fluids to be used just before analysis, thus enhancing assay efficiency and reducing the risk of fluid degradation.
Implementation Method 1
a deformable bladder configured for compressing the fluid permeable foam to induce fluid flow through the fluid outlet
Implementation Method 2
the fluid chamber in the ejection head is important in providing fluid to be ejected through nozzle holes in a nozzle plate of the ejection head and in maintaining an adequate backpressure to prevent fluid from drooling out of the nozzle plate
Implementation Method 3
The flow inducing pump is activated to cause fluid to flow from the outlet of the fluid reservoir into the fluid ejection head to prime the fluid ejection head with fluid from the fluid reservoir
Data Source
AI summary
A fluid reservoir for a fluid ejection head structure and a method for priming a fluid ejection head for a fluid dispensing device. The fluid reservoir includes an enclosed fluid cavity therein configured for containing fluid, a fluid outlet in fluid flow communication with the enclosed fluid cavity, and a flow inducing pump attached to the fluid reservoir opposite the fluid outlet.