Liquid Ejecting Head Adhesive Distribution Control
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Solution Overview
Problem
The existing liquid ejecting heads face breakage issues due to adhesive escaping from bonding surfaces and accumulating unevenly on the diaphragm, leading to concentrated load and potential breakage when the piezoelectric element is driven.
Innovation Solution
The design includes a pressure chamber substrate with non-overlapping supply and discharge openings relative to acute angle portions, which limits adhesive flow into communication holes, ensuring uniform adhesive distribution and preventing concentration of load on the diaphragm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the pressure chamber substrate and communication plate are bonded using liquid adhesive, then the bonding strength is improved, but the adhesive escapes from the bonding surface and accumulates unevenly on the diaphragm causing breakage
Solution Approach 1:
The patent extracts and removes the harmful element (adhesive) from critical areas by providing adhesive removal openings that allow excess adhesive to escape from the pressure chamber, preventing accumulation on the diaphragm while maintaining bonding strength at the bonding surface
Solution Approach 2:
The patent introduces adhesive removal openings as an intermediary structure that mediates between the bonding process and the diaphragm protection, providing a controlled path for adhesive evacuation without compromising the bonding interface
2Ease of operation
If the adhesive flows along the boundary of each surface constituting the pressure chamber by capillary force, then the adhesive distributes itself, but the distribution becomes uneven on the diaphragm leading to load concentration
Solution Approach 1:
The patent removes excess adhesive from the system through adhesive removal openings before it can accumulate unevenly on the diaphragm, ensuring uniform adhesive distribution by extracting the harmful surplus
Solution Approach 2:
The patent converts the harmful capillary flow that causes uneven distribution into a beneficial process by providing controlled escape paths through adhesive removal openings, transforming the uncontrolled flow problem into a managed evacuation system
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 stabilizes the adhesive distribution, disperses the load on the diaphragm, and reduces the likelihood of breakage during piezoelectric element operation.
Implementation Method 1
a part of the adhesive escapes from a bonding surface, enters the pressure chamber from the two acute angle portions formed in the pressure chamber, and flows along the boundary of each surface constituting the pressure chamber by a capillary force
Data Source
AI summary
A liquid ejecting head includes a pressure chamber substrate in which wall surface portions of a pressure chamber are formed, an diaphragm that forms a top surface portion of the pressure chamber, a piezoelectric element that is provided on the diaphragm, and a communication plate, in which an upper surface of the communication plate is bonded to a lower surface of the pressure chamber substrate by an adhesive, the upper surface of the communication plate is provided with a supply opening and a discharge opening, the pressure chamber is longitudinal in an X direction, acute angle portions are formed by the wall surface portions that mutually form an acute angle at each end in the X direction of a bottom surface portion of the pressure chamber, and the acute angle portions do not overlap with the supply opening and the discharge opening in a laminating direction.