Liquid Discharge Head Epoxy Resin Support Member Peeling
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Solution Overview
Problem
Conventional liquid discharge heads face issues with member peeling due to differences in coefficients of linear expansion, leading to unstable liquid discharge, especially in harsh environments or with varying types of liquids.
Innovation Solution
A liquid discharge head is designed with a flow channel forming member and a support member, where the support member is formed from a cured product of a specific epoxy resin composition that includes an epoxy resin with an epoxy group at the end of its molecular chain, preventing peeling from the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional resin compositions are used for the support member, then manufacturing is easier, but peeling occurs due to thermal expansion differences
Solution Approach 1:
The patent changes the chemical composition parameters of the photosensitive resin, specifically incorporating epoxy resins with flexible spacers and controlling the ratio of rigid to flexible components. This modifies the thermal expansion characteristics of the cured resin to match the substrate, preventing peeling while maintaining manufacturability through standard photolithography processes.
Solution Approach 2:
The patent creates a composite photosensitive resin composition combining epoxy resins with flexible spacers, rigid backbone structures, and photocationic polymerization initiators. This composite material achieves both thermal expansion compatibility with substrates and adequate mechanical strength, resolving the contradiction between reliability and ease of manufacture.
2Reliability
If the support member is made from standard photosensitive resin, then the manufacturing process is simpler, but liquid discharge becomes unstable in harsh environments
Solution Approach 1:
The patent modifies the resin composition parameters to include specific epoxy resins with flexible spacers containing ether or ester groups, along with rigid backbone structures. This parameter optimization ensures the cured support member maintains dimensional stability under thermal and chemical variations, guaranteeing stable liquid discharge in harsh environments while using a manufacturable photocationic curing system.
3Strength
If a rigid support member is used, then structural strength is higher, but stress-induced peeling occurs due to coefficient of linear expansion differences
Solution Approach 1:
The patent adjusts the molecular structure parameters of the epoxy resin by incorporating flexible spacers with specific chain lengths and types (ether or ester groups) between rigid aromatic rings. This creates a balanced material that provides adequate structural strength while having a coefficient of linear expansion matching the substrate, preventing stress-induced peeling.
Solution Approach 2:
The patent applies local quality by designing the resin molecule with both rigid segments (for strength) and flexible spacer segments (for thermal expansion compatibility). The rigid backbone provides structural integrity while the flexible spacers locally accommodate thermal stress, preventing peeling at the substrate interface.
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
This configuration ensures stable liquid discharge regardless of manufacturing or usage conditions, including harsh environments and varying liquids, by suppressing stress-induced peeling.
Implementation Method 1
a photocationic polymerization initiator, and the first photosensitive resin composition includes a photosensitive resin
Data Source
AI summary
A liquid discharge head including: a substrate having a liquid supply port; a flow channel forming member that is provided on the substrate and has discharge ports for discharging a liquid and a liquid flow channel that makes the liquid supply port and the discharge ports communicate with each other; and a support member that is provided on the substrate and arranged to be in contact with at least one surface of the flow channel forming member, with the one surface not being in contact with the liquid, wherein the flow channel forming member includes a cured product of a first photosensitive resin composition including a photosensitive resin, the support member includes a cured product of a second photosensitive resin composition including the epoxy resin A having a structure represented by formula (a1) or (a2) below in main chain structure:where, n1 and n2 represent integers of at least 2.