Droplet Ejection Ink Supply Control for Foam and Splash Suppression
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Solution Overview
Problem
Droplet ejection apparatuses face issues with liquid foaming in tanks, leading to erroneous liquid level detection and contamination of air channels due to splash, which existing methods fail to adequately address.
Innovation Solution
A droplet ejection apparatus with controlled liquid delivery speed based on air presence in the liquid channel, using a hardware processor to manage the delivery speed through a liquid deliverer, ensuring minimal air presence and reducing foaming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid is delivered quickly to fill tanks, then productivity is improved, but air remains in the liquid channel causing foaming and contamination
Solution Approach 1:
The system performs preliminary deaeration by delivering liquid at a first speed when air is detected in the liquid channel, then switches to a second (higher) speed after air is removed. This preliminary action of removing air before normal operation prevents foaming and contamination while enabling high-speed delivery afterward.
Solution Approach 2:
The liquid delivery speed is dynamically adjusted based on air detection results. The control section switches between first speed (lower) during deaeration and second speed (higher) during normal operation. This dynamic speed adjustment resolves the contradiction between productivity and contamination prevention.
2Productivity
If liquid delivery speed is increased, then productivity is improved, but liquid splashes causing air channel contamination
Solution Approach 1:
The system performs preliminary deaeration at a controlled first speed before switching to high-speed delivery. This preliminary action ensures the liquid channel is free of air that would cause splashing, thereby preventing contamination while enabling high-speed operation.
Solution Approach 2:
The system uses the presence of air as a trigger to control delivery speed. By detecting air and responding with appropriate speed control, the system converts the potentially harmful effect of air into a useful control mechanism that prevents contamination while maintaining productivity.
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
Suppresses foaming and contamination in tanks, maintaining accurate liquid level detection and preventing air channel contamination, particularly effective for UV ink and gel ink.
Implementation Method 1
When the liquid foams, a density decreases, and thus a buoyancy acting on the measurement section decreases
Data Source
AI summary
A droplet ejection apparatus includes: a plurality of tanks that store liquid; a droplet ejection head that ejects droplets; a liquid channel that communicates between a first tank and a second tank on a downstream side of the first tank in a liquid delivery direction; a liquid deliverer that delivers liquid from the first tank to the second tank; and a hardware processor that controls a liquid delivery speed of the liquid deliverer in accordance with an air amount present in the liquid channel and the second tank or an equivalent value equivalent to the air amount.