Liquid Ejection Head Protrusion Flow Guidance
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Solution Overview
Problem
The existing ink-jet head design results in uneven ink flow due to differences in resistance between sections of the second flow passages, leading to inadequate ink supply to certain areas of the manifold, causing potential printing issues.
Innovation Solution
The design incorporates protrusions in the horizontal passages that guide the ink to flow evenly into sections with higher resistance, ensuring uniform ink distribution by adjusting the inclination angles and shift positions of the protrusions relative to the vertical passages, thereby reducing pressure loss and ensuring consistent ink supply to all sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the first flow passages for different colors are shifted relative to one another in the conveyance direction to prevent interference, then the layout complexity is reduced, but the resistance to flow becomes uneven in the second flow passages, causing inadequate ink supply to certain manifold areas
Solution Approach 1:
The patent introduces protrusions at specific locations within the second flow passages to create localized flow guidance. These protrusions are strategically positioned to redirect ink flow into sections with higher resistance, ensuring that each section of the manifold receives adequate ink supply despite the asymmetric layout caused by shifted first flow passages.
Solution Approach 2:
The protrusions act as intermediary elements between the first flow passages and the manifold sections. They mediate the ink flow distribution by actively guiding the liquid into sections that would otherwise receive insufficient flow due to the resistance imbalance caused by the shifted passage arrangement.
2Ease of manufacture
If the first flow passage is connected to the second flow passage at a position shifted from the central portion, then the passage layout is simplified, but the resistance to flow differs between the two portions of the second flow passage, leading to non-uniform ink distribution
Solution Approach 1:
The protrusions create localized flow modification zones within the second flow passages. By positioning these protrusions at specific locations, the patent locally alters the flow characteristics to compensate for the asymmetric connection points, ensuring uniform ink distribution across all manifold sections while maintaining the simplified shifted layout.
Solution Approach 2:
The patent modifies the flow parameters by introducing protrusions that change the flow direction and distribution characteristics. This allows the system to achieve uniform ink distribution despite the asymmetric connection positions, effectively adjusting the flow parameters to compensate for the layout simplification.
3Reliability
If protrusions are added to guide ink flow evenly into sections with higher resistance, then ink distribution uniformity is improved, but the device complexity increases
Solution Approach 1:
Rather than implementing a complex overall redesign, the patent applies localized protrusions at specific critical points within the second flow passages. This targeted approach achieves uniform ink distribution by modifying only the necessary local areas, minimizing the increase in overall device complexity while effectively solving the flow distribution problem.
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 ensures that ink flows uniformly into both sections of the horizontal passages, reducing the risk of inadequate ink supply and improving printing consistency by minimizing pressure loss and optimizing ink distribution.
Implementation Method 1
The design incorporates protrusions in the horizontal passages that guide the ink to flow evenly into sections with higher resistance
Implementation Method 2
adjusting the inclination angles and shift positions of the protrusions relative to the vertical passages, thereby reducing pressure loss
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A liquid ejection head, including: nozzles (10); and a supply passage through which a liquid is supplied to the nozzles, wherein the supply passage includes (a) a first flow passage (67a-67d) and (b) a second flow passage (66a-66d) connected to the first flow passage-and-including two sections that extend in different directions from a connected position at which the first flow passage is connected to the second flow passage, the liquid being supplied to the second flow passage from the first flow passage, wherein the second flow passage has a liquid flow resistance larger in a first section (66a1, 66b1, 66c2, 66d2) than in a second section (66a2, 66b2, 66c1, 66d1), and wherein a protrusion (65a-65d; 111a-111d; 121a-121d; 131a-131d) protruding toward the first flow passage is provided on an inner wall surface of the second flow passage facing the first flow passage, for permitting the liquid to more easily flow from the first flow passage into the first section than the second section.