Liquid Ejecting Head Gas Trapping Chamber Design
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Solution Overview
Problem
Existing liquid ejecting apparatuses face issues with gas permeation into the ink passage, leading to bubble formation and pressure loss, which complicates the printing process and requires frequent cleaning operations, and the use of gas permeable films is inefficient and prone to damage under pressure changes.
Innovation Solution
A liquid ejecting apparatus with a gas trapping chamber and a gas collecting chamber, where a gas permeable wall separates the two, and a pressure difference generating unit creates a lower pressure in the collecting chamber to collect trapped gas, reducing the need for frequent cleaning and minimizing ink consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gas permeable film is disposed on the liquid chamber to degas ink, then gas can be removed from the ink passage, but the film is prone to damage under pressure changes and requires precise pressure control
Solution Approach 1:
The liquid passage is segmented into multiple chambers: a first liquid chamber for ink storage, a second liquid chamber for degassing, and a pressure chamber for ejection. The gas permeable wall is localized only in the second liquid chamber, separating it from the other functional chambers. This segmentation protects the gas permeable wall from high pressure conditions while maintaining its gas removal function.
Solution Approach 2:
The second liquid chamber acts as an intermediary zone between the ink storage and the pressure chamber. Gas permeable wall interposed between the first liquid chamber and the second liquid chamber allows gas to be removed from ink in this intermediate zone before ink enters the high-pressure pressure chamber, protecting the gas permeable wall from damage.
2Reliability
If cleaning operations are performed frequently to remove bubbles, then bubble accumulation is prevented, but ink consumption increases and printing efficiency decreases
Solution Approach 1:
Gas is removed from ink in advance during storage in the second liquid chamber before the ink is supplied to the pressure chamber for ejection. The gas permeable wall interposed between the first liquid chamber and the second liquid chamber enables continuous passive degassing, preventing bubble accumulation without requiring frequent cleaning interruptions.
Solution Approach 2:
The gas removal process operates continuously as long as ink is stored in the first liquid chamber and pressure difference exists between chambers. This continuous degassing action maintains bubble-free ink supply throughout operation, eliminating the need for periodic cleaning stops and maintaining constant printing productivity.
3Reliability
If pressure difference is applied across the gas permeable wall to enhance gas collection, then gas removal efficiency improves, but the risk of film damage and ink permeation increases
Solution Approach 1:
The pressure system is segmented so that high pressure is applied only to the pressure chamber for ejection, while the first and second liquid chambers maintain low pressure for safe gas permeation. The gas permeable wall is positioned in the low-pressure second liquid chamber, isolating it from high-pressure conditions while still enabling effective gas collection through controlled pressure difference.
Solution Approach 2:
Different pressure conditions are applied to different regions: low pressure in the first and second liquid chambers where the gas permeable wall is located, and high pressure only in the pressure chamber for ejection. This local differentiation of pressure quality enables effective gas collection without exposing the gas permeable wall to damaging high pressure.
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 traps and collects gas in the liquid passage, reducing bubble entry into the pressure chamber, minimizing pressure loss, and maintaining the integrity of the gas permeable wall, thus enhancing the reliability and efficiency of the printing process.
Implementation Method 1
a gas permeable wall interposed between the first liquid chamber and the second liquid chamber
Implementation Method 2
a pressure difference generating unit operable to generate a pressure difference between the first liquid chamber and the second liquid chamber
Data Source
AI summary
A liquid ejecting head has a pressure chamber into which liquid flows from a liquid reservoir through a liquid passage, and a pressure generating unit operable to pressurize the liquid in the pressure chamber to eject the liquid through a nozzle opening. A gas trapping chamber is formed in the liquid passage and adapted to trap gas mixed in the liquid. A gas collecting chamber is formed adjacent to the gas trapping chamber. A gas permeable wall is interposed between the gas trapping chamber and the gas collecting chamber. A pressure difference generating unit is operable to generate a pressure difference between the gas trapping chamber and the gas collecting chamber so that a pressure in the gas collecting chamber is lower than a pressure in the gas trapping chamber, thereby collecting the gas trapped in the gas trapping chamber in the gas collecting chamber through the gas permeable wall.