Liquid Ejection Head Bypass Channel Flow Management
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Solution Overview
Problem
In liquid ejection heads, ink components settle at the corners of the discharge branch channel due to opposing flow directions in the supply and discharge branch channels, leading to inefficiencies and potential clogging.
Innovation Solution
A liquid ejection head design featuring a supply manifold, a return manifold, and a bypass channel, where the supply manifold and return manifold are stacked with protrusions and recesses to facilitate even flow and reduce settling, and the bypass channel connects them to disperse ink components and prevent air bubbles from getting trapped.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the common supply branch channel and common discharge branch channel are stacked with opposing flow directions, then the structure is compact and space-efficient, but ink components settle at the corner of the common discharge branch channel
Solution Approach 1:
The invention introduces a bypass channel that extends in the array direction (horizontal dimension) to connect the supply manifold and return manifold, providing an additional flow path dimension. This allows ink to flow horizontally through the bypass channel instead of only vertically through the stacked branch channels, preventing component settling while maintaining the compact stacked structure.
Solution Approach 2:
The bypass channel acts as an intermediary flow path between the supply manifold and return manifold. By introducing this intermediate horizontal channel, the invention mediates the flow between the stacked supply and discharge branch channels, allowing ink components to be transported without settling at the corner of the common discharge branch channel.
2Device complexity
If ink flows in opposite directions in stacked supply and discharge branch channels, then the manifold structure is compact, but flow velocity decreases and settling occurs
Solution Approach 1:
The invention creates a dynamic flow system where ink can travel through multiple paths (supply branch channel, bypass channel, and return branch channel) with varying flow velocities. The bypass channel provides an additional dynamic route that enhances overall flow velocity by preventing stagnation and settling in the stacked branch channels.
3Speed
If the bypass channel connects supply manifold and return manifold directly, then ink flow velocity increases and settling is reduced, but air bubbles may be trapped
Solution Approach 1:
The invention segments the flow path into multiple sections: the supply branch channel, the bypass channel with its opening, and the return branch channel. This segmentation allows different flow characteristics in each section, enabling high velocity flow through the bypass channel while providing opportunities for air bubble discharge at the opening, thus resolving the contradiction between speed and reliability.
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 design enhances ink flow velocity, reduces settling of ink components, and effectively discharges air bubbles, improving the overall efficiency and reliability of the liquid ejection process.
Implementation Method 1
The bypass channel connects the supply manifold and the return manifold
Implementation Method 2
The first forming unit includes a first top surface defining a top surface of the return manifold, and a first protrusion protruding downward from the first top surface and having a lower end at which the bypass channel is open
Data Source
AI summary
A liquid ejection head includes pressure chambers arrayed in an array direction, a supply manifold extending in the array direction, a return manifold disposed below the supply manifold, and a bypass channel. Each pressure chamber receives a pressure for ejecting liquid from a corresponding nozzle. The supply manifold communicates with the pressure chambers and includes a supply opening through which liquid enters from an exterior. The return manifold is formed by a first forming unit to extend in the array direction and communicate with the pressure chambers, and includes a return opening through which liquid exits to the exterior. The bypass channel connects the supply manifold and the return manifold. The first forming unit includes a first top surface defining a top surface of the return manifold, and a first protrusion protruding downward from the first top surface and having a lower end at which the bypass channel is open.