Curved Nozzle Geometry for Bubble-Free Liquid Ejection
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Solution Overview
Problem
Existing liquid ejecting heads face issues with nozzle surface breakage and bubble mixing due to improper nozzle design, leading to unstable ink ejection.
Innovation Solution
The liquid ejecting head features a nozzle design with a first nozzle portion having a constant width in the second direction and a second nozzle portion with a width that gradually increases, reducing the rate of increase as it approaches the second surface, to minimize bubble mixing and stabilize ink ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the second nozzle portion has a linearly inclined inner surface with respect to the plate thickness direction, then the manufacturing is simplified, but the liquid surface breaks and bubbles are mixed into the nozzle
Solution Approach 1:
The patent changes the geometric parameters of the second nozzle portion from a linearly inclined surface to a curved surface where the inclination angle varies along the flow direction. Specifically, the inner surface is designed to have a smaller inclination angle near the first nozzle portion and a larger inclination angle near the second surface, creating a gradual transition that prevents liquid surface breakage while maintaining manufacturability through controlled curvature.
Solution Approach 2:
The patent applies curvature to the inner surface of the second nozzle portion by designing it as a curved surface rather than a straight inclined plane. This curvature allows the inclination angle to change gradually along the flow direction, smoothing the liquid flow and preventing meniscus breakage that would occur with abrupt linear transitions.
2Productivity
If the nozzle width increases rapidly to improve liquid flow, then the ejection efficiency increases, but the liquid surface breaks and bubbles are introduced
Solution Approach 1:
The patent controls the width increase of the second nozzle portion by designing the inner surface with a specific curvature profile. The width gradually increases from the connection position toward the second surface, with the rate of increase being smaller near the first nozzle portion and larger near the second surface. This controlled parameter change ensures smooth liquid flow expansion without meniscus breakage, maintaining both ejection efficiency and bubble-free operation.
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 effectively prevents bubble mixing and stabilizes ink ejection, ensuring consistent and efficient operation of the liquid ejecting head.
Implementation Method 1
an energy generation element that generates energy for ejecting a liquid from the nozzle
Data Source
AI summary
When a direction in which the flow path substrate and the nozzle substrate are stacked is defined as a first direction, and a direction orthogonal to the first direction is defined as a second direction, the nozzle includes a first nozzle portion passing from the first surface to a connection position in the nozzle substrate and a second nozzle portion that is a hole passing from the connection position to the second surface, the first nozzle portion has a constant width in the second direction regardless of a position in the first direction, and the second nozzle portion has a width in the second direction that gradually increases such that an amount of increase in width in the second direction decreases as a position in the first direction approaches the second surface.