Liquid Discharge Head Asymmetric Flow Path Air Bubble Prevention
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Solution Overview
Problem
Existing liquid discharge heads face challenges in preventing air bubbles from being pulled into pressure chambers, which can lead to discharge failures due to uneven flow speeds in the distribution flow path.
Innovation Solution
The liquid discharge head incorporates a distribution flow path with a first opening and a second opening, where the center of the second opening is biased to one side, and at least one bend portion is formed on the inner wall, ensuring that air bubbles are less likely to be pulled into the pressure chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first inner wall is made perpendicular to the first and second openings, then the flow speed difference is enhanced and air bubbles are prevented from stagnating on the second wall surface side, but it becomes difficult to achieve this configuration when opening positions are determined by discharge element substrate and flow path members
Solution Approach 1:
The first inner wall is designed with an asymmetric configuration where it is inclined relative to the second opening rather than being perpendicular to both openings. This asymmetric design creates a flow path geometry that promotes air bubble movement toward the first opening while maintaining compatibility with the fixed positions of the discharge element substrate and flow path members.
Solution Approach 2:
The inclination angle of the first inner wall is specifically optimized to create different flow characteristics at different locations within the distribution flow path. The local geometry of the first inner wall is tailored to enhance flow velocity in regions where air bubble stagnation would otherwise occur, while maintaining overall structural compatibility.
2Reliability
If the center of the second opening is biased to one side with respect to the center of the first opening, then flow speed variation occurs that prevents air bubble stagnation on the second wall surface side, but this configuration may not be achievable when opening positions are constrained by discharge element substrate and flow path members
Solution Approach 1:
The distribution flow path employs an asymmetric layout where the second opening is positioned with its center biased relative to the first opening. This asymmetric arrangement creates intentional flow speed variations that guide air bubbles toward the first opening and prevent their accumulation on the second wall surface side, while adapting to the constrained positioning requirements of the discharge element substrate and flow path members.
3Reliability
If air bubbles stagnate in the distribution flow path near the discharge element substrate, then air bubbles are mixed into pressure chambers causing discharge failure, but increasing flow speed difference may compromise flow distribution uniformity
Solution Approach 1:
The first inner wall is designed with a specific inclination angle that creates localized flow acceleration in critical regions where air bubble stagnation would occur. This local geometric modification enhances flow velocity selectively in areas adjacent to the discharge element substrate, preventing air bubble accumulation and ensuring stable discharge, while maintaining overall flow distribution uniformity through careful angle optimization.
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 effectively prevents air bubbles from entering the pressure chambers, thereby reducing the occurrence of discharge failures and ensuring stable ink discharge.
Implementation Method 1
Liquid, flowing through a narrow flow path from a flow path member upstream of the discharge element substrate, is distributed, by a distribution flow path formed in the supporting member, into a plurality of pressure chambers
Data Source
AI summary
The distribution flow paths each include a first opening located on the discharge element substrate side, and a second opening located on an opposite side of the first opening. In a predetermined direction, an opening width of the first opening is larger than an opening width of the second opening, and a center of the opening width of the second opening is biased to one side with respect to a center of the opening width of the first opening. At least one bend portion is formed on an inner wall of the distribution flow path located on the one side. In a use state of the liquid discharge head, a bend portion closest to the first opening among the at least one bend portion is located on an opening side of a center portion of the distribution flow paths in a vertical direction.