Liquid Ejection Head Pitch Conversion Flow Passages
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Solution Overview
Problem
In liquid ejection heads, the formation of pitch conversion flow passages by molding resin often results in obstructed resin flow, sink marks, and deteriorated flatness due to complex configurations, affecting joining reliability and ink flow efficiency.
Innovation Solution
A liquid ejection head design with a repeating pattern of pitch conversion flow passages arranged in groups, where the number of passages in a group is greater than the number of common liquid chambers, ensuring improved resin moldability and reduced pressure loss, thereby enhancing the flatness and joining reliability of the member surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pitch conversion flow passages are arranged in a complex configuration to supply liquid to multiple ejection orifices, then the liquid distribution capability is improved, but the resin flow is obstructed and sink marks are formed
Solution Approach 1:
The pitch conversion flow passages are divided into multiple groups, with each group containing a specific number of passages (greater than the number of common liquid chambers). This segmentation allows the resin to flow more easily through organized sections rather than a complex monolithic structure, reducing obstruction and sink marks while maintaining the capability to distribute liquid to multiple ejection orifices.
Solution Approach 2:
Different regions of the pitch conversion flow passage structure are designed with different characteristics. The passages within each group are arranged to optimize local resin flow patterns, while the overall structure maintains the necessary complexity for liquid distribution. This local optimization ensures that resin can flow smoothly in each section without being obstructed by the global complexity.
2Productivity
If the number of pitch conversion flow passages is increased to serve more ejection orifices, then the printing speed is improved, but the joining reliability is deteriorated
Solution Approach 1:
By segmenting the pitch conversion flow passages into groups with controlled numbers of passages, the structure can accommodate a high total number of passages for high printing speed while maintaining manageable local structures. Each group can be joined reliably without the cumulative complexity compromising overall joining reliability.
Solution Approach 2:
Instead of increasing the number of passages and then trying to manage the complexity, the design inverts the approach by first organizing passages into groups with optimal numbers, then combining these groups. This reverse engineering approach ensures that joining reliability is maintained at each stage while achieving the desired high printing speed through the total number of passages.
3Measurement precision
If pitch conversion flow passages are densely arranged to increase ejection orifice density, then the printing resolution is improved, but the resin moldability is deteriorated
Solution Approach 1:
The dense arrangement of pitch conversion flow passages is organized into groups, where each group contains a specific number of passages. This segmentation creates regular patterns within the dense structure, allowing resin to flow through predictable paths rather than navigating random complexity. The high density is maintained for printing resolution, while the grouped organization preserves resin moldability.
Solution Approach 2:
Within each group of densely arranged passages, the local configuration is optimized for resin flow, while the overall dense arrangement maintains high ejection orifice density for printing resolution. The local quality of each group ensures manufacturability, while the global density achieves the required printing precision.
Data Source
AI summary
A liquid ejection head includes ejection orifices for ejecting liquid, common liquid chambers connected to the ejection orifices, common flow passages, and pitch conversion flow passages that connects the common flow passages and liquid chambers to each other. The pitch conversion flow passages includes a periphery formed with resin. In a case where a number of pitch conversion flow passages in a group is minimum on a condition that one or more of the pitch conversion flow passages are respectively included in the group, the pitch conversion flow passages have a repeating pattern in which the group is repeatedly arranged. At least one of two pitch conversion flow passages adjoining an m-th pitch conversion flow passage (m is all integers from 1 to n−2, where n is an integer of 3 or more) is one of first to (m+1)-th pitch conversion flow passages.