Liquid Ejection Head Supply Layout to Reduce Bubble Retention
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Solution Overview
Problem
Bubbles in the supply flow channel of liquid discharge heads can hinder liquid flow due to buoyancy differences, leading to insufficient supply to the reservoir.
Innovation Solution
The liquid discharge head design includes a supply member configuration where the direction of liquid supply to the reservoir aligns with the direction of buoyancy, minimizing bubble retention and ensuring uninterrupted liquid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the supply flow channel is configured to supply liquid from a direction intersecting with gravity, then liquid can be supplied to the reservoir, but bubbles may remain in the supply flow channel due to buoyancy differences, hindering liquid flow
Solution Approach 1:
The supply flow channel is designed with an asymmetric configuration where the liquid supply direction intersects with the gravitational direction at a specific angle. This asymmetric arrangement creates a flow path where liquid enters from the side rather than from above or below, allowing bubbles to be pushed along with the liquid flow rather than rising against it. The channel geometry ensures that the liquid flow vector has both horizontal and vertical components, creating a diagonal flow path that prevents bubble accumulation.
Solution Approach 2:
Instead of supplying liquid from above (against gravity) or from below (with gravity), the invention inverts the conventional approach by supplying liquid from the side at an intersecting angle. This inversion of the supply direction eliminates the direct conflict between buoyancy forces and supply flow, as bubbles are no longer forced to move directly against or with gravity but are carried along by the diagonally directed liquid flow.
2Quantity of substance
If bubbles remain in the supply flow channel, then buoyancy forces act on bubbles opposite to liquid supply direction, but this causes insufficient liquid supply to the reservoir
Solution Approach 1:
The invention converts the harmful effect of bubble buoyancy into a beneficial alignment by orienting the supply flow channel such that the liquid flow direction intersects with gravity. This configuration causes bubbles to be carried along with the liquid flow in the same direction, transforming the potential harmful buoyancy force into a neutral or even beneficial effect where bubbles naturally follow the flow path without obstructing liquid supply.
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
Prevents insufficient liquid supply to the reservoir by reducing bubble retention in the flow channels, thereby maintaining consistent operation.
Implementation Method 1
when bubbles are mixed in the supply flow channel, the bubbles may remain in the supply flow channel due to a difference in the direction of buoyancy acting on the bubbles and the direction in which the liquid is supplied to the reservoir
Data Source
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AI summary
A liquid discharge head (8) according to an embodiment includes: a flow channel member (24) including a first surface (24a) and a second surface (24b) located opposite to the first surface (24a), a pressing unit located on the first surface (24a), and a supply member (21) connected to the flow channel member (24). The flow channel member (24) includes a plurality of discharge holes (243) located in the second surface (24b). The supply member (21) includes, in this order from an upstream side, a first supply flow channel (41), a first connection flow channel (42) connected to the first supply flow channel (41), and a reservoir (43) connected to the first connection flow channel (42), the first connection flow channel (42) being connected to the second surface (24b) side of the reservoir (43).