Patterned Non-Wetting Coating for Fluid Ejector Orifice
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Solution Overview
Problem
Fluid accumulation on the exterior surface of fluid ejectors, such as ink-jet printheads, can divert or block fluid ejection due to surface tension, and existing non-wetting coatings like Teflon and fluorocarbon polymers are soft, expensive, and difficult to pattern.
Innovation Solution
A fluid ejector design featuring a non-wetting region surrounding the orifice and more wetting regions on the exterior surface, formed from materials like fluorocarbon polymers or silicon-based monomers, with a patterned coating that includes a gold layer and alkanethiol monolayer, allowing for efficient fluid removal using a detachable faceplate and wiper or gas stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-wetting coatings such as Teflon and fluorocarbon polymers are applied to the exterior surface, then fluid accumulation is reduced, but the coating material becomes soft, expensive, and difficult to pattern
Solution Approach 1:
The patent applies non-wetting coating selectively to specific regions of the exterior surface - particularly in regions away from the orifice where fluid accumulation occurs - while leaving other regions uncoated or with different coating properties. This localized approach maintains fluid prevention benefits while reducing overall material cost and simplifying the patterning process compared to full-surface coating.
2Reliability
If non-wetting coatings are applied to prevent fluid accumulation, then fluid ejection stability improves, but cleaning steps are still required and manufacturing complexity increases
Solution Approach 1:
The exterior surface is divided into distinct regions with different coating properties: non-wetting regions for fluid prevention and wetting regions (or uncoated regions) for controlled fluid removal. This segmentation allows the surface to perform multiple functions - preventing accumulation in some areas while enabling cleaning in others - thereby maintaining ejection stability without requiring additional cleaning mechanisms or complex continuous patterning.
Solution Approach 2:
The patterned coating design enables the surface to clean itself by utilizing the wetting regions where accumulated fluid can be naturally removed through capillary action or minimal intervention, reducing or eliminating the need for external cleaning steps while maintaining the non-wetting properties in fluid ejection regions.
3Reliability
If traditional non-wetting coatings are used, then fluid accumulation is prevented, but direct contact cleaning is required which causes wear and reduces lifetime
Solution Approach 1:
The patterned coating introduces wetting regions as intermediary zones between the non-wetting coated areas and the cleaning mechanism. These wetting regions allow fluid to be channeled and removed without requiring direct contact between cleaning elements (such as wipers) and the coated surface, thereby preventing wear on both the coating and cleaning elements while extending component lifetime.
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 design stabilizes fluid discharge, reduces cleaning frequency, increases fluid ejector lifetime, and eliminates the need for direct contact, leading to faster printing rates and lower manufacturing costs.
Implementation Method 1
When fluid accumulates on the exterior surface adjacent to the orifice, further fluid ejected from the orifice can be diverted from an intended path of travel or blocked entirely by interaction with the accumulated fluid (e.g., due to surface tension).
Implementation Method 2
moving a wiper laterally across the faceplate
Implementation Method 3
The non-wetting region may be formed from a layer of gold onto which an alkanthiol monomer is adsorbed.
Data Source
Figure 1A~1C
Figure 2A~2E
Figure 3A~4B
AI summary
A fluid ejector is provided, having an internal surface, an external surface, an orifice that allows fluid in contact with the internal surface to be ejected, a first non-wetting region of the external surface, and one or more second regions of the external surface that are more wetting than the first non-wetting region. A process for cleaning the fluid ejectors is provided that includes detachably securing a faceplate to the fluid ejector and moving a wiper laterally across the faceplate.