Liquid Ejecting Head Flexible-Member Fixation for Wrinkle Reduction
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Solution Overview
Problem
The mismatch in linear expansion coefficients between the first and second members in a liquid ejecting head, such as an ink jet recording head, leads to wrinkles in the flexible member due to the use of thermosetting adhesives during high-temperature curing, affecting the ejection performance.
Innovation Solution
A liquid ejecting head design where the flexible member has a flexible region overlapping the flow path opening and an outer peripheral region with specific fixation, ensuring the linear expansion coefficient of the first member is smaller than that of the second member, with at least 60% of the outer peripheral region fixed only to the first member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermosetting adhesive is used to bond elements in the liquid ejecting head, then bonding strength is improved, but wrinkles occur in the flexible member due to linear expansion coefficient mismatch between members
Solution Approach 1:
The flexible member is designed with different fixation characteristics in different regions: the first region (60% or more of outer peripheral region) is fixed only to the first member, while the second region is fixed to both members. This local differentiation allows the flexible member to accommodate thermal expansion differences without developing wrinkles, while still maintaining sufficient bonding strength through the adhesive.
Solution Approach 2:
The design changes the fixation parameter of the flexible member by creating distinct regions with different bonding configurations. By controlling which regions are fixed to which members, the system accommodates the linear expansion coefficient mismatch between the first member (smaller coefficient) and second member (larger coefficient) during adhesive curing, preventing wrinkle formation while maintaining bonding integrity.
2Stability of the object's composition
If the flexible member is fixed to both members, then structural stability is improved, but the flexible region cannot properly absorb pressure fluctuations
Solution Approach 1:
The flexible member is designed with spatially differentiated fixation: the first region (60% or more of outer peripheral region) is fixed only to the first member, allowing it to move freely with pressure fluctuations, while the second region is fixed to both members, providing structural stability. This local quality differentiation simultaneously achieves both stability and flexibility where needed.
Solution Approach 2:
The flexible member is segmented into functionally distinct regions: a first region that is fixed only to the first member and can deform to absorb pressure fluctuations, and a second region that is fixed to both members and provides structural stability. This segmentation allows each region to perform its specific function optimally without compromising the other.
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
Reduces the occurrence of wrinkles, maintaining the flexible region's ability to absorb pressure fluctuations and ensuring consistent ink ejection characteristics by minimizing crosstalk and flow path resistance.
Implementation Method 1
a flexible member having a first surface fixed to a first fixing surface of the first member and a second surface opposite to the first surface and fixed to the second member
Implementation Method 2
since the linear expansion coefficient of the second member that pinches the flexible member is different from the linear expansion coefficient of the first member, there was a concern that wrinkles would occur in the flexible member when the thermosetting adhesive used to bond each element contained in the liquid ejecting head was cured at a high temperature and then returned to room temperature
Data Source
AI summary
A liquid ejecting head includes a first member that defines a portion of a common liquid chamber communicating with nozzles, a second member that has a linear expansion coefficient larger than that of the first member, and a flexible member that is fixed to the first member and the second member, in which the flexible member includes a flexible region that is not fixed to both the first member and the second member, and an outer peripheral region between the flexible region and a region that is fixed to both the first member and the second member, and the outer peripheral region has a first region that is fixed to the first member but not fixed to the second member, the first region occupying 60% or more of the entire periphery of the outer peripheral region.