Selective Anti-Wetting Coating for Print Head Nozzles
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Solution Overview
Problem
Existing methods for applying anti-wetting coatings to nozzle surfaces in print heads face challenges in selectively applying the coating to the exterior surface without coating the inside of the nozzle, leading to jetting problems due to ink contamination and adherence issues with etch resist during the etching process.
Innovation Solution
A method involving a silicon substrate coated with a fluorinated alkyl group compound, followed by modification to increase wetting properties for etch resist adhesion, etching to form through holes, and subsequent modification to restore anti-wetting properties by plasma treatment or heating, ensuring the coating is only on the exterior surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an anti-wetting coating is applied to the nozzle surface to prevent ink contamination, then ink adhesion is reduced, but the coating may enter the nozzle interior and cause jetting problems
Solution Approach 1:
The patent applies different surface properties to different locations: the exterior nozzle surface has anti-wetting properties (low surface energy) to prevent ink adhesion, while the interior nozzle surface maintains wetting properties (high surface energy) to ensure proper ink jetting. This is achieved through selective coating application methods that deposit coating material only on the exterior surface.
Solution Approach 2:
The patent applies the anti-wetting coating to the substrate before forming the nozzle holes through etching. This preliminary coating application ensures that the coating is present on the exterior surface before the nozzle interior is created, and subsequent selective removal or protection steps ensure the interior remains uncoated.
2Manufacturing precision
If an etch resist is applied to a substrate with anti-wetting coating for selective etching, then etching can be controlled, but the etch resist may not adhere to the coated substrate
Solution Approach 1:
The patent applies the anti-wetting coating before applying the etch resist, and uses selective removal or protection techniques to ensure the etch resist adheres only to areas where it is needed. The coating is removed or protected from areas where etching should occur, allowing precise control of the etching process.
Solution Approach 2:
The patent introduces an intermediary step or material that facilitates adhesion between the etch resist and the anti-wetting coated substrate. This may involve selective removal of the coating in patterned areas, or application of an adhesion promoter layer that bridges the anti-wetting coating and etch resist.
3Ease of manufacture
If the substrate is modified to increase wetting property for etch resist adhesion, then etch resist can be applied, but the anti-wetting property is reduced
Solution Approach 1:
The patent creates local variations in surface properties: areas intended for etching have increased wetting properties to allow etch resist adhesion, while areas intended to maintain anti-wetting properties preserve their low surface energy. This spatial differentiation resolves the contradiction between needing wetting for manufacturing and anti-wetting for final performance.
Solution Approach 2:
The patent dynamically adjusts surface properties during the manufacturing process. The substrate surface is modified temporarily to increase wetting for etch resist application, then subsequently restored or differentiated to provide anti-wetting properties in the final product. This temporal sequence allows both requirements to be met at different stages.
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 approach effectively prevents ink from adhering to the nozzle surface while maintaining the anti-wetting properties on the exterior, preventing jetting issues and ensuring the inside of the nozzle remains uncoated, thus improving print head performance.
Implementation Method 1
Applying a coating on the substrate by reacting the substrate with a compound comprising at least a fluorinated alkyl group
Implementation Method 2
Modifying the coated substrate to decrease the wetting property of the coated substrate
Implementation Method 3
Modifying the coated substrate to restore anti-wetting properties by plasma treatment or heating
Implementation Method 4
anti-wetting coating may be applied to the nozzle surface to prevent ink from staying on the nozzle surface
Data Source
AI summary
Disclosed is a method for preparing a nozzle surface provided with a coating having anti-wetting and anti-fouling property. The method is based, for example, on the self-healing property of the coating used in the method. Also disclosed is a nozzle surface having such coating and a print head having the nozzle surface.