Ink Ejection Head Unit Air Bubble Evacuation via High-Resistance Path
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Solution Overview
Problem
Existing ink ejection systems face issues with air penetration and accumulation in the sub tank, leading to reduced air tightness and ink quality, especially when the ink chamber enters a negative pressure state or during assembly and usage of valve systems.
Innovation Solution
The proposed ink ejection head unit incorporates a common liquid chamber with a supply opening and ejection opening, connected to a sub tank with an ink containing section, a supply path, an ejection path, and a communication path where the fluid resistance of the communication path is higher than the total fluid resistance from the supply opening to the ejection opening, allowing for efficient air bubble evacuation without an atmosphere open device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an elastic sealing system with a closed slit is used in the air evacuation section, then the sub tank can evacuate air, but air tightness deteriorates when the ink chamber enters negative pressure state
Solution Approach 1:
The patent removes the elastic sealing system with closed slit from the air evacuation section and replaces it with a dedicated communication path that has high fluid resistance. This extraction eliminates the air tightness problem caused by the elastic material while preserving air evacuation functionality through the high-resistance communication path that prevents air infiltration during negative pressure states.
Solution Approach 2:
The patent creates a specialized communication path with specifically high fluid resistance located between the ink containing section and the ejection path. This local quality modification ensures that air bubbles can be evacuated while the high resistance prevents air from infiltrating during negative pressure conditions, addressing the air tightness issue at a specific location without compromising overall air evacuation capability.
2Reliability
If an atmosphere open valve is provided to communicate the sub tank with atmosphere, then air can be evacuated, but foreign matter invades and creates gaps reducing air tightness
Solution Approach 1:
The patent eliminates the atmosphere open valve system entirely and replaces it with a communication path that utilizes the existing ejection path infrastructure. This extraction removes the vulnerability to foreign matter invasion while maintaining air evacuation capability through the high-resistance communication path that allows air bubbles to escape during normal operation.
Solution Approach 2:
The communication path acts as an intermediary mechanism that enables air evacuation without requiring direct communication with the atmosphere. By using the existing ejection path infrastructure with high fluid resistance, the system mediates between the need for air evacuation and the need to prevent foreign matter invasion, eliminating the need for separate atmosphere opening mechanisms.
3Reliability
If separate ink introduction and air evacuation sections are provided, then air accumulation is suppressed, but device complexity increases
Solution Approach 1:
The patent merges the air evacuation function with the existing ejection path by providing a communication path that connects the ink containing section to the ejection path. This combination eliminates the need for separate air evacuation sections and valve systems while maintaining effective air accumulation suppression, as air bubbles naturally rise and can escape through the high-resistance communication path during normal ejection operations.
Solution Approach 2:
The communication path serves multiple functions: it enables air bubble evacuation from the ink containing section while utilizing the existing ejection path infrastructure. This multi-functionality reduces device complexity by eliminating dedicated air evacuation components while maintaining the reliability of air accumulation suppression through the high fluid resistance characteristic of the communication path.
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 configuration effectively prevents air invasion and ensures efficient air bubble evacuation, maintaining ink quality and preventing air accumulation, thereby enhancing the reliability and performance of ink drop ejection.
Implementation Method 1
A fluid resistance of the communication path is larger than the total fluid resistance of a path starting from the supply opening to the ejection opening of the head
Implementation Method 2
air bubble in a tank can be efficiently evacuated without arranging an atmosphere-opening device
Data Source
AI summary
An ink ejection head unit includes a head that ejects ink drops from plural two nozzles. The head includes a common liquid chamber connected to the plural nozzles. The common liquid chamber has a supply opening and an ejection opening. A tank is connected to the head and includes an ink containing section that contains ink to be supplied to the head. Also included is a supply path to supply the ink from the ink containing section to the supply opening of the head. An ejection path is provided to eject the ink ejected from the ejection opening of the head to an outside of the ink ejection head unit. A communication path is also provided to communicate the highest section of a seal of the containing section with the ejection path higher than the highest section of the seal. A fluid resistance of the communication path is larger than the total fluid resistance of a path starting from the supply opening to the ejection opening.