Liquid Discharge Head Flow Channel Structure for Air Bubble Management
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Solution Overview
Problem
Ink jet recording apparatuses face issues with air bubbles entering pressure chambers, affecting ink jet characteristics, as existing flow channel structures do not effectively prevent air bubbles from entering or efficiently discharge them from the supply manifold to the feedback manifold.
Innovation Solution
A liquid discharge head with a flow channel structure where the supply ports are positioned closer to the end of the supply manifold and feedback ports closer to the center of the feedback manifold, optimizing flow speeds to minimize air bubble intrusion into pressure chambers and facilitate easy discharge of air bubbles to the feedback manifold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air bubbles are allowed to flow through the supply manifold, then liquid circulation is maintained, but air bubbles intrude into pressure chambers causing ink jet characteristic variation
Solution Approach 1:
The patent applies local quality by creating different flow conditions in different regions of the supply manifold. The central region has higher flow velocity that prevents air bubble intrusion into pressure chambers, while the end regions have lower flow velocity where air bubbles are discharged to the feedback manifold. This spatial differentiation of flow characteristics resolves the contradiction between maintaining liquid circulation and preventing air bubble intrusion.
Solution Approach 2:
The patent employs asymmetry in the positioning of supply ports and feedback ports relative to the supply manifold geometry. Supply ports are positioned at specific locations that take advantage of the asymmetric flow distribution in the manifold, where the central high-velocity region protects against air bubble entry while end regions facilitate air bubble discharge. This asymmetric configuration optimizes the balance between liquid supply and air bubble management.
2Productivity
If supply ports are positioned in the center of the supply manifold, then liquid supply efficiency is improved, but air bubbles more easily intrude into pressure chambers
Solution Approach 1:
The patent positions supply ports at specific locations within the supply manifold that exploit the local flow characteristics. Rather than uniformly distributing supply ports or concentrating them only in the center, the patent strategically places them to take advantage of the high-velocity central flow region that prevents air bubble intrusion while maintaining efficient liquid supply to pressure chambers.
3Ease of manufacture
If feedback ports are positioned at the end of the feedback manifold, then structure simplicity is maintained, but air bubbles are not efficiently discharged
Solution Approach 1:
The patent positions feedback ports at specific locations in the feedback manifold that optimize air bubble discharge efficiency. By placing feedback ports where the flow conditions favor air bubble removal, the patent achieves effective air bubble discharge while maintaining a relatively simple overall manifold structure. The positioning leverages the natural flow patterns to enhance air bubble removal without requiring complex additional components.
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 configuration reduces the likelihood of air bubbles entering pressure chambers and ensures efficient discharge of air bubbles from the supply manifold to the feedback manifold, maintaining consistent ink jet characteristics and preventing variations in ink flow.
Implementation Method 1
The flow speed of the liquid flowing in a center portion of the supply manifold in the third direction is faster than the flow speed of the liquid flowing in the vicinity of the end of the supply manifold in the third direction
Implementation Method 2
the flow speed of the liquid flowing in the vicinity of the center of the feedback manifold in the third direction is faster than the flow speed of the liquid flowing in the vicinity of the end of the feedback manifold in the third direction
Data Source
AI summary
A liquid discharge head includes: a supply manifold; a feedback manifold; and a plurality of individual flow channels. Each of the individual flow channels includes: a supply portion, a descender portion, and a feedback portion. The supply manifold has a plurality of supply ports, and the feedback manifold has a plurality of feedback ports. A distance between the center of the supply manifold in one direction and the plurality of supply ports of the supply manifold is longer than ¼ of a width of the supply manifold in the one direction, and a distance in the one direction between the center of the feedback manifold in the one direction and the plurality of feedback ports of the feedback manifold is shorter than ¼ of a width of the feedback manifold in the one direction.