Liquid Ejecting Head Surface Layout for Stronger Mold Bonding
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Solution Overview
Problem
The bond strength between the fixing plate and the adhesive in liquid ejecting heads is low due to the water repellent film on the surfaces, leading to ink intrusion and potential peeling of the mold, which compromises the integrity of the liquid ejecting mechanism.
Innovation Solution
A liquid ejecting head design featuring a fixing plate with a water repellent region and a hydrophilic region, where the mold is bonded to the hydrophilic region, enhancing the bond strength and reducing ink intrusion by using a mold with higher liquid resistance than the adhesive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a water repellent film is formed on the surface of the fixing plate to prevent ink adhesion, then ink repellency is improved, but bond strength between the fixing plate and adhesive deteriorates
Solution Approach 1:
The fixing plate is designed with different surface properties in different regions: the first surface (nozzle side) has a water repellent film for ink repellency, while the second surface (adhesive bonding side) has a hydrophilic region that enhances adhesive bonding. This local differentiation resolves the contradiction by providing ink repellency where needed while ensuring strong bonding at the adhesive interface.
2Length of stationary object
If the fixing plate is made relatively thin to reduce size, then device compactness is improved, but bond strength between the lateral surface and adhesive deteriorates
Solution Approach 1:
The lateral surface of the fixing plate is designed with a hydrophilic region that provides enhanced adhesive bonding properties. This local modification allows the thin fixing plate to maintain strong bonding at critical interfaces despite its reduced overall thickness.
3Object-affected harmful factors
If a water repellent film is formed on the nozzle plate surface to prevent ink adhesion, then ink repellency is improved, but bond strength between the nozzle plate and adhesive deteriorates
Solution Approach 1:
The nozzle plate is designed with different surface properties: the ejection surface has a water repellent film for ink repellency, while the peripheral surface that contacts the adhesive has a hydrophilic region. This local differentiation ensures ink repellency at the nozzle while maintaining strong adhesive bonding at the 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
The improved bond strength and reduced ink intrusion enhance the reliability and stability of the liquid ejecting head by preventing ink ingress and maintaining structural integrity.
Implementation Method 1
a hydrophilic region that is disposed between the water repellent region and the lateral surface, and has lower water repellency than the water repellent region, and part of mold is bonded to the hydrophilic region of the first surface
Data Source
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AI summary
A liquid ejecting head includes: a head chip; a fixing plate having a first surface facing in an ejection direction, a second surface that is opposite from the first surface, and a lateral surface; and a holder configured to hold the head chip between itself and the fixing plate. In a plan view as seen toward the first surface, the first surface includes a water repellent region having water repellency, and a hydrophilic region that is disposed between the water repellent region and the lateral surface, and has lower water repellency than the water repellent region, and part of mold is bonded to the hydrophilic region of the first surface, the mold being disposed between the lateral surface and at least one of the head chip or the holder.