Liquid Discharge Head Return Branching Channel Bubble Removal
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Solution Overview
Problem
Bubbles accumulating in the filter of a liquid discharge head's return channel can cause clogging, leading to reduced liquid supply to individual channels, increased channel resistance, and potential ink leakage from nozzles.
Innovation Solution
A liquid discharge head design featuring a return branching channel branching off from the upstream portion of the return channel, with a valve system allowing for bubble removal by routing ink flow through the branching channel, preventing filter clogging and maintaining consistent channel resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a return filter is provided in the return channel to inhibit foreign matter from invading individual liquid chambers, then the reliability of liquid circulation is improved, but bubbles accumulate in the upstream portion of the filter causing clogging which worsens the reliability and increases channel resistance
Solution Approach 1:
The return channel is segmented into a main return channel and a branching return channel. The return filter is positioned in the main return channel, while the branching channel provides an alternative flow path that bypasses the filter. This segmentation allows liquid to be divided into multiple streams, with one stream filtered and another stream serving as a backup path when the filter becomes clogged with bubbles.
Solution Approach 2:
A communication channel is introduced as an intermediary element connecting the upstream portion of the return channel with the downstream portion. This communication channel acts as a mediator that allows liquid to bypass the filter when necessary, enabling the system to maintain flow even when the filter is blocked by accumulated bubbles.
2Reliability
If a return filter is provided in the return channel, then foreign matter is filtered from the liquid, but the channel resistance of the return channel increases requiring greater pump driving force
Solution Approach 1:
The return channel is divided into multiple parallel paths: one through the return filter and another through the communication channel. This segmentation creates multiple flow routes, allowing liquid to distribute across lower-resistance paths when the filter path becomes blocked, thereby reducing the overall channel resistance and the energy required by the pump.
Solution Approach 2:
The system uses partial filtration by allowing only a portion of the liquid to pass through the return filter at any given time, with the remainder flowing through the communication channel. This partial action approach prevents complete blockage and maintains adequate flow with reduced pump energy requirements.
3Reliability
If a return filter is provided in the return channel, then foreign matter is filtered, but the channel resistance at upstream side from nozzle becomes different from downstream side, breaking meniscus and causing liquid leakage
Solution Approach 1:
The return channel is segmented into multiple parallel flow paths that distribute liquid flow more evenly. By providing alternative routes through the communication channel, the system balances the resistance across different segments of the channel, preventing excessive pressure differences that would disrupt the meniscus and cause leakage.
Solution Approach 2:
The communication channel is designed to equalize the pressure distribution across the return channel system. By providing an alternative flow path that connects upstream and downstream portions, the system maintains more uniform pressure (potential) throughout the channel, preventing the pressure imbalances that cause meniscus breakdown and liquid leakage.
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
Effectively prevents filter clogging and maintains consistent channel resistance, ensuring stable ink supply and preventing nozzle meniscus breakage and leakage.
Implementation Method 1
the liquid moves from the storage chamber to flow through the supply channel, each of the individual channels, the return upstream portion, and the return branching channel by driving the pump
Data Source
AI summary
A liquid discharge head includes: individual channels respectively including nozzles; a supply channel allowing an outlet of a storage chamber storing a liquid to communicate with an inlet of each of the individual channels; a return channel allowing an outlet of each of the individual channels to communicate with an inlet of the storage chamber; a return filter provided in the return channel; and a return branching channel branching off from a return upstream portion of the return channel. The return upstream portion is positioned upstream of the return filter.