Liquid Ejection Head Water-Repellent Projection Reduces Forward Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inkjet recording heads face issues with satellite droplets and mist formation, leading to poor printing quality and ejection stability, particularly during restarts, due to high forward resistance caused by protrusions designed to reduce satellite droplets and mist.
Innovation Solution
A liquid ejection head with a substrate and ejection orifice-forming member layers, including a protrusion and a water-repellent projection portion that projects farther into the ejection orifice, reducing forward resistance while maintaining ejection stability and printing quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If protrusions are formed within the ejection orifice to hold ink, then satellite droplets and mist are reduced, but forward resistance increases causing poor ejection stability during restarts
Solution Approach 1:
The invention applies different surface properties to different regions within the ejection orifice. The water-repellent projection portion creates a localized hydrophobic zone that differs from the surrounding hydrophilic regions formed by the protrusions. This local quality differentiation allows ink to be held effectively by the protrusions while the water-repellent region reduces forward resistance by preventing excessive ink adhesion to the orifice walls.
Solution Approach 2:
The water-repellent projection portion acts as an intermediary element between the ink and the ejection orifice walls. It mediates the interaction by providing a surface that the ink can contact without adhering strongly, thus reducing forward resistance while still allowing the protrusions to hold the ink effectively. This intermediary layer resolves the conflict between ink holding and resistance reduction.
2Reliability
If the ejection orifice-forming member is made thinner to reduce forward resistance, then ejection stability improves, but the rigidity and thickness of the member deteriorate
Solution Approach 1:
The invention changes the surface energy parameters of the ejection orifice-forming member by introducing the water-repellent projection portion. This parameter change (from hydrophilic to hydrophobic surface) reduces the adhesion between ink and the orifice walls, thereby reducing forward resistance and improving ejection stability without requiring changes to the physical thickness or structural rigidity of the forming member.
3Manufacturing precision
If protrusions are formed to decrease droplet tail length, then printing quality improves, but forward resistance increases leading to mist formation
Solution Approach 1:
The invention creates localized zones with different surface properties within the ejection orifice. The protrusions provide hydrophilic regions for ink holding that decrease droplet tail length, while the water-repellent projection portion creates a hydrophobic zone that prevents excessive ink adhesion and mist formation. This spatial differentiation of surface qualities resolves the contradiction between printing quality and mist reduction.
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 solution effectively decreases satellite droplets and mist, improving printing quality and ejection stability during restarts without compromising the thickness or rigidity of the ejection orifice-forming member.
Implementation Method 1
an intermediate water-repellent layer, and an ejection orifice-forming member layer B in this order from a substrate-side of the member... a water-repellent projection portion that is at least a portion of the intermediate water-repellent layer and that projects farther into the ejection orifice
Implementation Method 2
a water-repellent projection portion that is at least a portion of the intermediate water-repellent layer and that projects farther into the ejection orifice than the ejection orifice-forming member layer A and the ejection orifice-forming member layer B
Data Source
AI summary
A liquid ejection head includes a substrate; and an ejection orifice-forming member formed on the substrate and including an ejection orifice configured to eject liquid and a liquid channel communicating with the ejection orifice. The ejection orifice-forming member includes an ejection orifice-forming member layer A, an intermediate water-repellent layer, and an ejection orifice-forming member layer B in this order from a substrate-side of the member. The ejection orifice-forming member also includes a protrusion protruding into the ejection orifice, and the ejection orifice-forming member includes a water-repellent projection portion that is at least a portion of the intermediate water-repellent layer and that projects farther into the ejection orifice than the ejection orifice-forming member layer A and the ejection orifice-forming member layer B.