Liquid Ejection Head With Gas-Permeable Bubble Removal
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Solution Overview
Problem
Existing liquid ejection heads face instability due to the difficulty in effectively discharging bubbles through permeable partitions with large thickness, leading to inefficient operation.
Innovation Solution
A liquid ejection head design incorporating a bubble discharge mechanism with a deformable membrane and a gas permeable film, coupled with a unidirectional pump system, to manage pressure differentials and efficiently remove bubbles, ensuring stable ink ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a permeable partition with large thickness is used, then the structural strength and sealing performance are improved, but the bubble discharge capability deteriorates
Solution Approach 1:
The partition is divided into two distinct components: an impermeable partition wall providing structural strength and sealing, and a separate gas permeable film positioned at the bubble accumulation position. This segmentation allows each component to perform its specialized function without compromise - the impermeable wall maintains pressure differential while the permeable film enables bubble discharge.
Solution Approach 2:
A gas permeable film acts as an intermediary component between the ink supply chamber and the external environment. This film selectively permits gas molecules to pass through while maintaining the pressure differential needed for ink ejection, thereby mediating between the conflicting requirements of structural integrity and bubble discharge capability.
2Productivity
If a large pressure difference is applied to discharge bubbles through a thick permeable partition, then the bubble removal efficiency is improved, but the energy consumption and system complexity increase
Solution Approach 1:
A gas permeable film with microporous structure is employed at the bubble accumulation position. This porous material allows gas molecules to pass through under minimal pressure differential, enabling efficient bubble removal without requiring large pressure differences that would increase energy consumption and pump workload.
3Reliability
If bubbles accumulate in the ink supply chamber, then the stability of liquid ejection deteriorates, but the frequency of bubble discharge operations increases
Solution Approach 1:
The gas permeable film is pre-positioned at the bubble accumulation position within the ink supply chamber. This preliminary arrangement enables continuous or near-continuous passive bubble discharge throughout operation, preventing bubble accumulation before it adversely affects ejection stability, rather than requiring periodic active discharge interventions.
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 enhances the stability and reliability of the liquid ejection process by maintaining optimal pressure conditions and preventing bubble accumulation, thereby improving print quality and efficiency.
Implementation Method 1
a gas (bubbles) trapped in an upper filter chamber is caused to permeate through a permeable partition and collected into a gas collection hollow portion by using a pressure difference
Implementation Method 2
collected into a gas collection hollow portion by using a pressure difference
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
The liquid ejection head (1) includes: an ejection port (13) for ejecting the liquid; a pressure chamber (12) provided with an energy generation element (15) configured to generate an energy for ejecting the liquid from the ejection port (13); and a unit (770) configured to remove a bubble from the liquid to be supplied to the pressure chamber (12). The unit (770) has: a liquid reservoir chamber fluidly communicating with one end of the pressure chamber (12) and capable of holding the liquid; a gas permeable film (710) capable of letting a gas permeate therethrough; a depressurization chamber (760) adjoining the liquid reservoir chamber with the gas permeable film (710) therebetween; and a deformation suppression unit (720) configured to contact the gas permeable film (710) to suppress deformation of the gas permeable film (710).