Liquid Ejection Head Siloxane Bonding for Ink-Durable Damping
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Solution Overview
Problem
Existing liquid ejection heads face issues with adhesive reliability between the damper film and adhesive due to deterioration when immersed in ink, leading to peeling, which affects the performance of adjacent nozzles.
Innovation Solution
The use of a siloxane bond between the organic film and adhesive, which enhances initial adhesive strength and maintains durability even when immersed in ink, utilizing materials like polyimides and epoxy resins with plasma treatment to generate functional groups for improved bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If ester bonds are used to bond the organic film and adhesive (as disclosed in WO 2020/045112), then initial adhesive strength is improved, but adhesive strength deteriorates over time when immersed in ink
Solution Approach 1:
The patent changes the chemical bonding parameter from ester bonds to siloxane bonds. This parameter change fundamentally alters the bond's chemical structure, providing both high initial strength and long-term durability in ink environments, as siloxane bonds resist degradation by ink components better than ester bonds
Solution Approach 2:
The patent employs composite material chemistry by combining silane coupling agents with the adhesive system. This creates a composite bonding mechanism where siloxane bonds form between the organic film and adhesive, integrating the benefits of both the organic film's damping properties and the siloxane bond's chemical stability in ink
2Reliability
If polyimides and LCP materials are used for the damper film, then ink resistance and heat resistance are improved, but adhesive adherence becomes difficult
Solution Approach 1:
The patent introduces silane coupling agents as intermediary substances between the polyimide/LCP damper film and the adhesive. These coupling agents act as chemical mediators that bond to both the organic film and adhesive, overcoming the inherent difficulty of adhering to these chemically stable materials while maintaining their ink and heat resistance
Solution Approach 2:
The patent changes the surface chemistry parameter of the polyimide/LCP film through plasma treatment or silane coupling agent application. This parameter change creates reactive sites on the film surface that enable strong chemical bonding with adhesives, while the bulk material properties (ink resistance, heat resistance) remain unchanged
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
The siloxane bond ensures high initial adhesive strength and resistance to ink, preventing peeling and maintaining effective damping performance, suitable for inkjet recording devices.
Implementation Method 1
the organic film and the adhesive are bonded through a siloxane bond
Implementation Method 2
the film comprising the heat-resistant resin is subjected to surface treatment, such as a plasma treatment, to generate ester bonds with the resin composition and improve adherence
Data Source
AI summary
A liquid ejection head comprising an ejection port for ejecting liquid; a pressure chamber in which pressure acts on the liquid ejected from the ejection port; a flow path communicating with the pressure chamber; a substrate forming the flow path; and an organic film for constituting a part of a wall surface of the flow path and suppressing vibration of the liquid in the flow path, wherein the organic film is adhered, with an adhesive, to the substrate, and the organic film and the adhesive are bonded through a siloxane bond.