Fluidic Dispensing Device Diaphragm Backpressure Mixing
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Solution Overview
Problem
Existing fluidic dispensing devices face challenges in maintaining effective backpressure and preventing fluid separation, especially when the fluid settles or separates within capillary members, leading to difficulties in remixing and maintaining consistent ink delivery in printheads.
Innovation Solution
A fluidic dispensing device with a diaphragm having a deflection axis, where a portion of the diaphragm is displaceable along the deflection axis, creating a variable volume fluid reservoir and utilizing a stir bar for fluid mixing and redistribution, ensuring consistent backpressure and preventing fluid separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a capillary member is used to control backpressure, then backpressure is maintained, but fluid settling and separation occur making remixing impossible
Solution Approach 1:
The patent applies the dynamics principle by making the diaphragm movable rather than fixed. The diaphragm can deflect along a deflection axis to change the volume of the fluid reservoir dynamically, creating pressure variations that drive fluid circulation and mixing. This dynamic volume change prevents fluid settling and separation while maintaining backpressure control.
Solution Approach 2:
The patent uses a magnetic stir bar as an intermediary mixing element. The stir bar, driven by a magnetic field, acts as a mediator to actively mix the fluid in the reservoir. This intermediary component directly addresses the fluid homogeneity problem by mechanically stirring the fluid to prevent separation.
2Stress or pressure
If a movable wall with spring is used to maintain backpressure, then backpressure is maintained, but device complexity increases
Solution Approach 1:
The patent uses a flexible diaphragm instead of a rigid movable wall with spring. The diaphragm is a thin, flexible membrane that can deflect to change volume and maintain backpressure without requiring complex spring mechanisms or rigid moving parts. This simplifies the overall device structure while achieving the same backpressure control function.
Solution Approach 2:
The patent extracts the spring component from the traditional movable wall design and replaces it with a purely elastic diaphragm structure. The diaphragm's inherent elasticity provides the restoring force needed for backpressure control, eliminating the need for separate spring elements and reducing structural complexity.
3Ease of operation
If the diaphragm deflection axis is parallel to the ejection chip plane, then fluid delivery is simplified, but mixing efficiency decreases
Solution Approach 1:
The patent introduces asymmetry in the diaphragm deflection geometry. Instead of symmetric deflection parallel to the ejection chip plane, the diaphragm deflects along an axis that creates asymmetric volume changes and fluid flow patterns. This asymmetric deflection enhances mixing by creating more complex fluid circulation patterns while still maintaining effective fluid delivery.
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 effectively maintains desired backpressure and prevents fluid separation, ensuring reliable and consistent fluid delivery by allowing the diaphragm to collapse and adjust volume while the stir bar promotes mixing, thereby maintaining efficient ink distribution and preventing clogging.
Implementation Method 1
a diaphragm having a dome portion and having a sealing surface, the sealing surface having a planar extent that surrounds the chamber. The sealing surface is in sealing engagement with the perimetrical end surface to define a fluid reservoir in fluid communication with the first opening. The diaphragm has a deflection axis, and the dome portion is displaceable along the deflection axis.
Implementation Method 2
a stir bar in the chamber, the stir bar having a rotational axis, wherein the rotational axis of the stir bar is substantially parallel to the planar extent of the ejection chip
Data Source
Figure 1~2
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Figure 6
AI summary
A fluidic dispensing device (110) is provided, comprising a body (122) having a chamber (148) with a perimetrical end surface (150-3), and a chip mounting surface defining a first plane and having a first opening; an ejection chip coupled to the chip mounting surface (140-2), the ejection chip (118) being in fluid communication with the first opening; and a diaphragm (130) having a dome portion (130-1), and having a sealing surface (131-6). The sealing surface has a planar extent that surrounds the chamber. The sealing surface is in sealing engagement with the perimetrical end surface to define a fluid reservoir (136) in fluid communication with the first opening, and the diaphragm has a deflection axis (188). The dome portion is displaceable along the deflection axis.