Liquid Ejection Head Compatible Layer Hydrophilicity
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Solution Overview
Problem
Existing ink jet head manufacturing methods face challenges with ink ejection failure, particularly when producing extremely small ejection orifices, due to low wetting properties and bubble accumulation in the flow path, leading to reduced hydrophilicity sustainability.
Innovation Solution
A method involving the formation of a resin layer pattern on a substrate with a hydrophilizing material, followed by a compatible layer creation between the resin and covering resin layers, to enhance the hydrophilicity and mechanical properties of the ink flow path surface, ensuring sustainable ink ejection performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an extremely small ejection orifice is produced to achieve high-precision recording, then recording precision is improved, but ink ejection failure occurs due to low wetting property and bubble accumulation
Solution Approach 1:
The patent applies local quality by treating only the inner surface of the flow path with a hydrophilizing material, while leaving other parts of the structure unchanged. This localized treatment improves wetting property specifically where ink flows, without affecting the overall head structure or requiring changes to the ejection orifice dimensions.
Solution Approach 2:
The hydrophilizing material acts as an intermediary substance between the ink and the flow path surface. This intermediate layer improves the interaction between ink and flow path by providing hydrophilic properties, thereby preventing bubble accumulation and ensuring reliable ink ejection through small orifices.
2Ease of manufacture
If a soluble resin is used to form the flow path pattern, then the flow path can be formed by elution, but the wetting property to high surface tension ink is low causing refilling deterioration
Solution Approach 1:
The hydrophilizing material is applied to the flow path inner surface in advance, before the soluble resin is eluted. This preliminary treatment ensures that when ink subsequently flows through the formed flow path, the surface already possesses hydrophilic properties that promote wetting and prevent bubble accumulation, thereby improving refilling performance.
Solution Approach 2:
The patent creates a composite structure by combining the soluble resin flow path with a hydrophilizing material layer on its inner surface. This composite approach maintains the manufacturing advantages of soluble resin while adding the functional property of hydrophilicity to improve ink wetting and refilling.
3Reliability
If the flow path surface is made hydrophilic by contacting with hydrophilizing material solution, then bubble accumulation is suppressed, but the hydrophilicity is not sustainable over time
Solution Approach 1:
The hydrophilizing material is incorporated into the flow path structure itself during manufacturing, rather than being applied as a separate coating that can degrade over time. This integration allows the flow path to maintain its hydrophilic properties inherently, enabling long-term sustainability of bubble accumulation suppression without requiring external maintenance or re-treatment.
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 method maintains hydrophilicity and enables favorable ink ejection for an extended period, even with extremely small ejection orifices, by incorporating a hydrophilizing material into the compatible layer, thereby improving the ink jet head's durability and performance.
Implementation Method 1
adding a hydrophilizing material represented by Chemical Formula 1 to an entire surface layer of the resin layer
Implementation Method 2
a covering resin layer that forms the ink flow path and contains an epoxy resin and a photocationic polymerization initiator is formed
Data Source
AI summary
Provided is a method for manufacturing a liquid ejection head including an ejection orifice for ejecting a liquid, a substrate and a flow path forming member that is joined to the substrate to form a liquid flow path communicating with the ejection orifice, the method including: (1) forming a resin layer having a flow path mold pattern, on the substrate; (2) adding a hydrophilizing material represented by Chemical Formula 1 to an entire surface layer of the resin layer; (3) forming a covering resin layer serving as the flow path forming member, on the resin layer and forming a compatible layer containing the resin layer, the covering resin layer and the hydrophilizing material, at an interface between the resin layer and the covering resin layer; (4) forming the ejection orifice by exposing the covering resin layer; and (5) forming a flow path by removing the resin layer.