Liquid Ejection Head Recesses to Prevent Adhesive Intrusion
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Solution Overview
Problem
Conventional liquid ejection heads face challenges in ensuring adhesive accuracy during manufacturing, as the adhesive can flow into pressure chambers due to reduced viscosity during curing, affecting ink ejection performance.
Innovation Solution
The liquid ejection head incorporates recess portions on the inner surface of the liquid supply path to prevent adhesive intrusion into pressure chambers by capturing and containing the adhesive during the curing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If convex portions made of photocurable adhesive are provided on the inner wall of the liquid supply path to inhibit adhesive flow, then adhesive flow is inhibited, but high accuracy is necessary for applying the adhesive which becomes difficult to ensure depending on the size of the recording element substrate
Solution Approach 1:
Instead of adding protruding convex portions that require precise adhesive application, the invention uses recess portions (grooves) in the liquid supply path inner wall. This inverted approach allows the adhesive to be contained passively during curing without requiring high precision in adhesive placement, thereby resolving the contradiction between reliability and manufacturing precision
Solution Approach 2:
The recess portions act as intermediary structures that capture and contain the adhesive during the curing process. These grooves serve as a mediator between the adhesive and the pressure chambers, preventing direct contact while allowing the adhesive to cure in a controlled manner without requiring precise application
2Strength
If the adhesive cures by heating, then the adhesive bonds the recording element substrate to the supporting member, but the viscosity of the adhesive is temporarily lowered by heat allowing it to reach the pressure chambers through capillary force
Solution Approach 1:
The recess portions are designed to counteract the harmful effect of heat-induced viscosity reduction before the adhesive can intrude into the pressure chambers. The grooves create a physical barrier that prevents capillary flow toward the pressure chambers even when the adhesive becomes temporarily less viscous during heating
Solution Approach 2:
The inner wall of the liquid supply path is given different local properties: recess portions are created at specific locations where adhesive containment is needed, while other areas maintain their original structure. This localized modification prevents adhesive intrusion without affecting the overall bonding function
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 design effectively reduces the likelihood of adhesive intrusion into pressure chambers, maintaining ink ejection functionality and performance by controlling adhesive flow.
Implementation Method 1
The adhesive that has become flowable due to lowered viscosity may reach the pressure chambers through an inner wall of a liquid supply path of the recording element substrate by capillary force
Data Source
AI summary
A liquid ejection head includes a recording element substrate and a supporting member. The recording element substrate includes ejection ports that eject liquid, pressure chambers that communicate with respective ejection ports and are supplied with the liquid, and a liquid supply path that supplies the liquid to the pressure chambers. The supporting member is joined with the recording element substrate via an adhesive. The liquid supply path faces a joining portion of the recording element substrate and the supporting member, and includes at least one recess portion on an inner surface of the liquid supply path.