Nozzle Plate Design for Stable Ink Droplet Discharge
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing inkjet head nozzle technologies face limitations in increasing nozzle density and maintaining stable droplet discharge due to issues with nozzle shape, surface orientation, and flow path resistance, leading to turbulence and stagnation.
Innovation Solution
A nozzle plate design featuring a first nozzle portion perpendicular to the substrate, a second nozzle portion with a larger cross-sectional area, and an inclined portion connecting them without stepped portions, allowing for smooth ink flow and high nozzle density, achieved through anisotropic dry etching and wet etching processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If anisotropic wet etching is used to form a nozzle, then the nozzle can be formed with a specific tapered shape, but the inclination angle depends on surface orientation limiting nozzle density increase
Solution Approach 1:
The patent changes the etching method from anisotropic wet etching to anisotropic dry etching, which allows independent control of the nozzle shape parameters. This enables the formation of nozzles with optimized inclination angles that are not constrained by crystal orientation, thereby increasing nozzle density while maintaining precise shape control.
2Shape
If anisotropic wet etching is used, then a tapered nozzle portion can be formed, but the end becomes square shaped making it hard to maintain droplet straight flying property
Solution Approach 1:
The patent changes the etching process to anisotropic dry etching and adjusts the etching conditions to achieve a circular cross-section at the nozzle end instead of a square shape. This maintains the tapered portion for flow control while ensuring the droplet exits in a straight direction, improving discharge reliability.
3Ease of manufacture
If a discharge outlet without perpendicular portion is used, then manufacturing is simplified, but it is hard to stably maintain a meniscus
Solution Approach 1:
The patent applies local quality by creating a perpendicular portion specifically at the discharge outlet region while maintaining the tapered shape in the upstream portion. This localized structural feature stabilizes the meniscus at the outlet without complicating the overall nozzle manufacturing process.
4Shape
If stepped portions are present in the nozzle, then different cross-sectional areas can be achieved, but turbulence and stagnation occur in ink flow
Solution Approach 1:
The patent replaces the stepped portions with a smoothly curved tapered shape that gradually transitions between different cross-sectional areas. This curvature eliminates abrupt changes in flow path geometry, preventing turbulence and stagnation while still achieving the desired variation in cross-sectional area for flow control.
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 improves discharge characteristics by preventing turbulence and enabling high nozzle density, allowing for stable and efficient ink droplet discharge with precise control over flow path resistance.
Implementation Method 1
forming a nozzle hole in a silicon substrate by anisotropic dry etching
Implementation Method 2
forming an inclined portion by anisotropic wet etching so that the inclined portion has a cross-sectional area gradually reducing from the second nozzle portion to the first nozzle portion
Data Source
AI summary
A nozzle plate includes a silicon substrate, and a nozzle hole formed in the silicon substrate for discharging a liquid droplet provided with: a first nozzle portion formed perpendicularly to a surface of the silicon substrate; a second nozzle portion formed on a same axis as an axis of the first nozzle portion and having a cross-sectional area that is larger than a cross-sectional area of the first nozzle portion; and an inclined portion having a cross-sectional area gradually increasing from the first nozzle portion to the second nozzle portion.