Liquid Ejection Head Filter Wall Design for Bubble Control
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Solution Overview
Problem
Existing liquid ejection heads face reliability issues due to dust and foreign matter entry, and air bubbles entrained during strong impacts or vibrations, leading to ejection failures and increased wasteful liquid consumption.
Innovation Solution
A liquid ejection head design featuring a substrate with a supply path, an ejection orifice forming member with a common liquid chamber, and an intermediate layer with a filter portion and protrusions that communicate via a filter portion with a plurality of holes, and a dividing wall that intersects the ejection orifice arrangement direction to prevent air bubble enlargement and improve filter performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filter is provided in the liquid ejection head to suppress dust and foreign matter entry, then reliability is improved, but the filter structure increases device complexity
Solution Approach 1:
The patent employs a porous layer as the filter structure in the liquid ejection head. This porous material allows liquid to pass through while trapping dust and foreign matter, achieving reliable filtration without requiring complex mechanical filter components. The porous structure is integrated into the existing head architecture, maintaining simplicity while ensuring consistent liquid flow and particle removal.
2Reliability
If suction is performed to remove air bubbles from the common liquid chamber, then ejection reliability is improved, but liquid consumption increases
Solution Approach 1:
The patent extracts air bubbles from the common liquid chamber through a suction mechanism that selectively removes gas phases while minimizing liquid loss. By targeting specifically the air bubble removal function and separating it from the main liquid supply path, the system achieves improved ejection reliability without proportionally increasing liquid consumption. The suction is applied locally at the bubble accumulation zone rather than throughout the entire liquid system.
3Manufacturing precision
If the filter portion has small holes to improve filtration performance, then dust removal efficiency is improved, but liquid flow resistance increases
Solution Approach 1:
The patent utilizes porous materials with optimized pore size distributions to achieve effective dust filtration while maintaining acceptable liquid flow characteristics. The porous structure provides numerous flow paths that compensate for the small individual pore sizes, reducing overall flow resistance. This approach enables high filtration performance without requiring large pressure differentials that would increase energy loss.
Solution Approach 2:
The patent extends the filtration function into the thickness dimension by using a porous layer with controlled depth. This three-dimensional porous structure provides extended filtration path length for particle capture while maintaining open porosity for liquid flow. The vertical dimension of the porous layer allows effective particle trapping without creating excessive flow resistance in the horizontal plane.
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 design enhances reliability by effectively filtering dust and foreign matter while minimizing wasteful liquid consumption during suction, maintaining high image quality and reducing the risk of air bubble-induced ejection failures.
Implementation Method 1
the supply path and the common liquid chamber communicate with each other via a filter portion including a plurality of holes formed in the intermediate layer
Data Source
AI summary
A liquid ejection head includes a substrate, an ejection orifice forming member having a plurality of ejection orifices for ejecting a liquid, and an intermediate layer provided between the substrate and the ejection orifice forming member. The substrate has a supply path for supplying the liquid to the plurality of ejection orifices, the ejection orifice forming member has a common liquid chamber communicating with the plurality of ejection orifices, the supply path and the common liquid chamber communicate with each other via a filter portion including a plurality of holes formed in the intermediate layer, the ejection orifice forming member has a wall portion that protrudes into the common liquid chamber at a position opposed to the filter portion, and the wall portion extends along a direction intersecting an arrangement direction of the plurality of ejection orifices.