Liquid Ejecting Head Downstream Gas Stabilization
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Solution Overview
Problem
Inkjet recording apparatuses face issues with unstable vortices between the recording head and medium due to densely formed ejection orifices and high ejection frequencies, leading to deviations in droplet landing positions and degradation of image quality.
Innovation Solution
A liquid ejecting head with gas discharge ports positioned downstream of the ejection orifices, discharging gas to join and stabilize the airflow vortex, reducing the amount of gas required and minimizing droplet deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If gas is strongly discharged to blow away the vortex, then the vortex effect is reduced, but the amount of gas discharge increases and droplet landing position deviation increases
Solution Approach 1:
Instead of discharging gas from the upstream side to blow away the vortex, the patent discharges gas from the downstream side to join and stabilize the vortex. This inverted approach transforms the harmful vortex into a stable flow pattern, reducing the need for large amounts of gas while improving droplet placement accuracy
Solution Approach 2:
The patent converts the harmful vortex generated by droplet ejection into a beneficial stable airflow pattern by discharging gas to join the vortex from the downstream side. This transforms the originally harmful unsteady vortex into a useful stable flow that improves recording quality
2Manufacturing precision
If ejection orifices are densely formed to improve image quality, then recording resolution improves, but vortex instability increases and droplet placement accuracy decreases
Solution Approach 1:
The patent introduces discharged gas as an intermediary substance between the ejection orifices and the surrounding air. This intermediary gas flow stabilizes the vortex and reduces harmful airflows, enabling dense ejection orifice arrangements to maintain both high image quality and stable droplet placement
3Productivity
If ejection frequency is increased to achieve high-speed recording, then productivity improves, but vortex instability increases and droplet placement accuracy decreases
Solution Approach 1:
The patent applies preliminary action by discharging gas from the downstream side before the vortex can become unstable. This proactive gas discharge prevents vortex instability from developing, enabling high ejection frequencies to be used without compromising droplet placement accuracy or recording quality
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 stabilizes the vortex, reducing droplet landing position deviations and improving image quality while reducing the amount of discharged gas, thus minimizing the impact on droplet accuracy and apparatus cost.
Implementation Method 1
an airflow that forms a vortex on an upstream side of the ejection orifices in the direction of relative movement of the recording medium as viewed from the liquid ejecting head. The vortex is generated by the liquid ejected from the ejection orifices
Implementation Method 2
a gas discharge port that allows gas to be discharged therefrom. The gas discharged from the gas discharge port joins an airflow that forms a vortex
Data Source
AI summary
A liquid ejecting head ejects liquid from a plurality of ejection orifices thereof for recording while being moved relative to a recording medium. The liquid ejecting head includes a gas discharge port configured to allow gas to be discharged therefrom. The gas discharge port is disposed on a downstream side of the ejection orifices in a direction of relative movement of the recording medium as viewed from the liquid ejecting head. The gas discharged from the gas discharge port joins an airflow that forms a vortex on an upstream side of the ejection orifices in the direction of relative movement. The vortex is generated by the liquid ejected from the ejection orifices.