Epoxy Adhesive for Liquid Ejecting Head Electrical Continuity
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Solution Overview
Problem
Existing liquid ejecting heads, such as ink jet recording heads, face issues with electrical continuity due to swelling of adhesive agents when exposed to ejected liquids, leading to loss of connectivity over time.
Innovation Solution
A liquid ejecting head is designed with a flow channel substrate and an actuator mount bonded using an epoxy adhesive agent containing p-aminophenol epoxy resin, bisphenol A epoxy resin, and bisphenol F epoxy resin, which prevents swelling and maintains electrical continuity even when exposed to the ejected liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a COF substrate is used to supply drive signals to piezoelectric elements, then electrical connection is achieved, but electrical continuity is lost during long-term use due to adhesive swelling
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive agent by specifying a particular formula containing p-aminophenol epoxy resin, bisphenol A epoxy resin, and bisphenol F epoxy resin in defined proportions. This parameter change prevents swelling when exposed to liquids, thereby maintaining electrical continuity during long-term use.
Solution Approach 2:
The patent uses a composite adhesive material formed by combining multiple epoxy resins (p-aminophenol epoxy resin, bisphenol A epoxy resin, and bisphenol F epoxy resin) with specific ratios. This composite formulation provides both bonding functionality and resistance to swelling, ensuring reliable electrical connection over time.
2Reliability
If adhesive agent is used to bond wiring substrate to actuator, then electrical connection is established, but adhesive swells when exposed to ejected liquid causing loss of connectivity
Solution Approach 1:
The patent modifies the chemical parameters of the adhesive agent by specifying a particular composition of epoxy resins that are resistant to swelling when exposed to liquids. This parameter change eliminates the harmful effect of swelling while maintaining the bonding function.
Solution Approach 2:
The patent converts the potential harm of adhesive exposure to liquid into a benefit by selecting epoxy resins that are specifically resistant to liquid-induced swelling. The adhesive maintains its bonding properties and electrical connectivity even when exposed to ejected liquid, turning a potential failure mode into a reliable long-term solution.
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 use of this specific epoxy adhesive agent ensures long-term operation of the liquid ejecting head without losing electrical continuity, as it significantly reduces swelling and maintains reliable electrical connections.
Implementation Method 1
The mount of the actuator and the wiring substrate are bonded together using an epoxy adhesive agent containing p-aminophenol epoxy resin, bisphenol A epoxy resin, and bisphenol F epoxy resin
Implementation Method 2
There are also piezoelectric elements on this side of the flow channel substrate, and the piezoelectric elements are displaced to change the pressure in appropriate pressure chambers, whereby ink droplets are discharged from appropriate nozzle openings
Data Source
AI summary
A liquid ejecting head has a flow channel substrate, an actuator formed on the flow channel substrate and having at least one mount, and a flexible wiring substrate electrically connected to the mount to supply a drive signal to the actuator. The mount of the actuator and the wiring substrate are bonded together using an epoxy adhesive agent containing p-aminophenol epoxy resin, bisphenol A epoxy resin, and bisphenol F epoxy resin.