Liquid Ejecting Head Inclined Bonding Surfaces
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Solution Overview
Problem
In liquid ejecting heads, excess adhesive can flow onto the diaphragm and hinder its displacement, causing inconsistency in ink ejection and deteriorating printing quality due to the adhesive's hardening on the diaphragm surface.
Innovation Solution
The pressure chamber substrate is bonded to the flow path forming substrate with an adhesive that has inclined portions with surfaces inclined relative to the diaphragm's normal direction, reducing the adhesive's flow onto the diaphragm by allowing it to flow away from the diaphragm's surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a protruding structure is used to block adhesive flow, then adhesive is prevented from reaching the diaphragm, but the structure creates steps parallel to the vertical direction that cause adhesive to flow downward
Solution Approach 1:
The patent applies asymmetry by changing the protruding structure from vertical steps to inclined surfaces. The inclined surfaces are angled relative to the vertical direction, creating an asymmetric geometry that redirects adhesive flow away from the diaphragm rather than allowing downward flow. This asymmetric shape modification effectively prevents the harmful adhesive flow while eliminating the problematic vertical step formation.
Solution Approach 2:
The patent introduces a new dimensional approach by using inclined surfaces instead of vertical protrusions. The inclined surfaces create a directional component in the horizontal dimension, guiding adhesive flow laterally away from the diaphragm area. This dimensional change in the protruding structure's geometry transforms the adhesive flow path from vertical downward movement to lateral diversion.
2Strength
If adhesive is applied to bond substrates, then substrates are joined together, but excess adhesive flows onto the diaphragm and hardens, hindering diaphragm displacement
Solution Approach 1:
The patent applies local quality by creating a localized adhesive flow control structure. The inclined surfaces are positioned specifically at the bonded portion where adhesive is applied, creating a local geometric feature that directs adhesive flow in a controlled manner. This localized structural modification ensures that adhesive bonding strength is maintained at the joint while preventing excess adhesive from reaching the diaphragm area, thus preserving diaphragm displacement consistency.
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 effectively suppresses the adhesive's flow onto the diaphragm, maintaining consistent vibration and ejection characteristics, thereby improving printing quality by preventing adhesive-induced inconsistencies.
Implementation Method 1
a piezoelectric element... vibrating a diaphragm forming a wall surface of the pressure chamber
Data Source
AI summary
A liquid ejecting head includes a pressure chamber substrate forming a pressure chamber in which an liquid is stored, a flow path forming substrate forming a flow path through which the liquid flows, a pressure portion applying a pressure to the liquid in the pressure chamber, and a diaphragm bonded to the pressure portion and vibrating with displacement of the pressure portion, in which the pressure chamber substrate is bonded to the flow path forming substrate with an adhesive and has inclined portions each having one or more inclined surfaces that are inclined with respect to a normal direction of a surface of the diaphragm in such a way that a width of the pressure chamber decreases toward the diaphragm.