Nozzle Plate Protrusions for Inkjet Ejection Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inkjet printing faces issues with image degradation due to ink droplet separation into satellite droplets and mist formation, especially when the ink evaporates in nozzles, leading to increased viscosity and ejection failures, and existing solutions like tapered ejection ports increase ejecting speed, causing more satellite droplets and mist.
Innovation Solution
A liquid ejection head design featuring a nozzle plate with a first ejection port and a smaller second ejection port, along with protrusions extending from the outer edge of the first port towards the center, which reduces resistance and suppresses satellite droplet formation by controlling the meniscus and liquid column dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a tapered ejection port is used to reduce resistance, then ejection stability is improved, but ejecting speed increases causing more satellite droplets and mist
Solution Approach 1:
The ejection port is divided into multiple sections: a first ejection port at the outer surface, a second ejection port at the bottom surface with smaller opening, and intermediate protrusions. This segmentation allows different zones to perform different functions - the first port reduces resistance while the second port and protrusions control liquid column formation to suppress satellite droplets
Solution Approach 2:
Different portions of the ejection port have different structural characteristics. The first ejection port has a larger opening to reduce resistance, while the second ejection port has a smaller opening and the protrusions create localized structures that control meniscus formation and liquid column dynamics, achieving local optimization for different functions
2Quantity of substance
If ink evaporates in nozzles during idle period, then viscosity increases, but ejection fails or ink is applied to unintended portions
Solution Approach 1:
The protrusions and dual ejection port structure are pre-configured to control meniscus formation and liquid column dynamics before ejection occurs. This preliminary structural arrangement ensures that even when ink viscosity changes due to evaporation, the ejection process remains stable and accurate
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 design effectively reduces ejection port resistance and minimizes satellite droplet and mist generation, improving ejection stability and efficiency while maintaining accurate ink placement.
Implementation Method 1
a plurality of protrusions that extend from an outer edge portion of the first ejection port towards a center portion of the second ejection port through the second ejection port
Implementation Method 2
The plurality of protrusions extend along the outer surface of the nozzle plate
Implementation Method 3
a substrate provided with an element that generates energy used to eject a liquid
Data Source
AI summary
An ejection port includes a first ejection port that is an opening portion formed on an outer surface side of a recessed portion formed in an outer surface of a nozzle plate, a second ejection port positioned on a bottom surface side of the recessed portion, the second ejection port including an opening portion that is smaller than the first ejection port, and a plurality of protrusions that extend from an outer edge portion of the first ejection port towards a center portion of the second ejection port through the second ejection port, in which a distance between tip portions of the plurality of protrusions and the substrate is larger than a distance between an outer edge portion of the second ejection port and the substrate.