Liquid Ejection Head Cover Stiffness and Airtightness
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Solution Overview
Problem
In liquid ejection heads, maintaining high airtightness and stiffness is challenging due to the elongated design, which can lead to warpage and stress on joints, particularly when using a face cover with a high aperture ratio, resulting in reduced reliability and potential peeling issues.
Innovation Solution
A liquid ejection head design incorporating a first cover member with a bent part and a second cover member that overlap, providing enhanced stiffness and airtightness while preventing excessive warpage, and using a flow path member to support the ejection port surface, ensuring reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the aperture ratio of the face cover is increased to expose more of the print element board, then the visibility and access to the ejection ports are improved, but the stiffness of the face cover decreases, leading to potential warpage and joining difficulties
Solution Approach 1:
The face cover is divided into multiple independent reinforcement parts (first reinforcement part and second reinforcement part) that are positioned at different locations. This segmentation allows each reinforcement part to independently support specific high-stress areas without interfering with the overall aperture design, thereby maintaining stiffness while preserving the high aperture ratio for board visibility and access.
Solution Approach 2:
Reinforcement parts are strategically placed only in specific local areas where stiffness is most needed, rather than uniformly across the entire face cover. This local reinforcement approach minimizes the impact on the overall aperture area while providing targeted structural support to prevent warpage and joining issues in critical regions.
2Strength
If the face cover is bent to increase stiffness, then the warpage and joining difficulties are reduced, but excessive bending causes warpage and makes it difficult to conform to the head region, leading to peeling during use
Solution Approach 1:
Instead of bending the entire face cover as a single piece, the reinforcement is segmented into multiple independent parts that are locally positioned. This segmentation reduces the overall bending requirement while still providing necessary stiffness in critical areas, thereby maintaining conformability to the head region and preventing peeling during use.
Solution Approach 2:
The reinforcement parts are positioned asymmetrically at specific locations rather than uniformly distributing reinforcement across the face cover. This asymmetric placement provides targeted stiffness where needed while maintaining flexibility and conformability in other areas, ensuring reliable joining without excessive warpage.
Data Source
AI summary
A liquid ejection head and a liquid ejection apparatus capable of maintaining high reliability include a first cover member including an aperture and covering a surface of a flow path member facing a print medium of the liquid ejection head, a second cover member covering a side surface of the liquid ejection head, and a displacement absorption part that absorbs the displacement between the first cover member and the second cover member. Furthermore, the space between the aperture and the flow path member is sealed with a sealing material.