Liquid Ejection Device Negative Pressure Ink Supply
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Solution Overview
Problem
Conventional liquid ejection devices, such as ink jet printers, face issues with air mixing into the ink supply, leading to potential ink ejection failures due to air being trapped in the supply system, which existing technologies struggle to prevent effectively.
Innovation Solution
A liquid ejection device with a liquid supply unit that includes a pressure chamber, first and second supply passages, a return passage, and a pump mechanism, which generates negative pressure to prevent air from entering the ejection head and ensures efficient ink circulation, using an air vent mechanism to remove air bubbles and a backflow prevention mechanism to prevent ink pressurization from reaching the ejection head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If ink is supplied from an ink cartridge to the liquid ejection head by water head difference, then the liquid ejection device can operate continuously, but air may enter the liquid supply unit and cause ink ejection failure
Solution Approach 1:
A liquid supply unit is introduced as an intermediary component between the ink cartridge and the liquid ejection head. This unit includes a pressure chamber that can be pressurized to expel air bubbles from the ink supply passage, thereby preventing air from reaching the ejection head while maintaining continuous ink supply capability
Solution Approach 2:
The system changes the pressure parameter in the liquid supply unit by introducing a pressurizing mechanism. When air bubbles are detected or suspected, the pressure in the pressure chamber is increased to expel the air bubbles from the ink supply passage, thus maintaining reliable ink ejection without interrupting continuous operation
2Reliability
If pressurized purging is performed to forcibly eject air from the ink discharge opening, then air can be removed from the system, but the liquid supply unit may become pressurized and cause uncontrolled ink ejection
Solution Approach 1:
The ink supply system is segmented into distinct functional zones: the ink cartridge, the liquid supply unit with pressure chamber, the ink supply passage, and the liquid ejection head. This segmentation allows pressurization to be applied locally to the pressure chamber for air removal without directly pressurizing the entire ink supply path to the ejection head, thus preventing uncontrolled ejection
Solution Approach 2:
The liquid supply unit acts as an intermediary buffer between the ink cartridge and the ejection head. The pressure chamber within this unit serves as a controlled environment for air bubble removal, isolating the pressurization process from the ejection path and preventing harmful uncontrolled ink ejection
3Reliability
If a liquid supply unit with pressure chamber is arranged in the supply passage, then air can be removed from the ink supply, but the device complexity increases
Solution Approach 1:
The liquid supply unit combines multiple functions into a single integrated component: ink storage (via the pressure chamber), air bubble removal (via pressurization), and ink supply control. By merging these functions into one unit that can be positioned in the supply passage, the design achieves effective air removal while minimizing the increase in overall device complexity compared to separate components for each function
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 prevents air from entering the ejection head, ensuring reliable ink ejection by maintaining a negative pressure environment and preventing ink pressurization, thus enhancing the stability and performance of the liquid ejection process.
Implementation Method 1
The pump mechanism is capable of circulating the liquid at least through the second supply passage, the common passage and the return passage
Implementation Method 2
a pressure chamber, capable of storing the liquid... arranged in a supply passage in the case of supplying ink from an ink cartridge to the liquid ejection head by a water head difference. By disposing the liquid supply unit for generating the negative pressure, unlimited dripping of the ink from the discharge hole is suppressed
Data Source
AI summary
A liquid ejection device includes a liquid ejection head and a liquid supply unit configured to supply liquid to the liquid ejection head. The liquid ejection head includes a plurality of liquid discharge holes, individual passages configured to individually supply the liquid to the respective liquid discharge holes, and a common passage configured to supply the liquid to the individual passages. The liquid supply unit includes a pressure chamber capable of storing the liquid, a first supply passage allowing communication between the liquid storage container and the pressure chamber, a second supply passage allowing communication between an upstream side of the common passage and the pressure chamber, a return passage allowing communication between a downstream side of the common passage and the pressure chamber, and a pump mechanism capable of circulating the liquid at least through the second supply passage, the common passage and the return passage.