Curved Flow-Path Member for Inkjet Head Air Bubble Management
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Solution Overview
Problem
The existing configurations of flow-path members in ink jet type recording heads limit the degree of freedom in the arrangement of flow paths, leading to potential air bubble retention and ejection failures, as they either restrict the flow velocity or allow air bubbles to collect in specific bifurcation flow paths.
Innovation Solution
A flow-path member design with a first bifurcation flow path portion where the upstream-side flow path has an R-shaped second wall surface and an acute angle with the downstream-side flow path, allowing air bubbles to easily move and distribute evenly, preventing collection in specific bifurcation flow paths and enhancing air-bubble discharge properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the connection flow path and manifold communicate with opposite direction components to ensure configuration freedom, then the degree of freedom in flow path configuration is improved, but the flow velocity of ink may be reduced causing air bubbles to remain
Solution Approach 1:
The patent applies curvature by forming the upstream-side flow path portion with a specific curved shape having a radius of curvature of 0.5mm or more. This curved configuration allows the flow path to bend smoothly, maintaining ink flow velocity while enabling the flow path to communicate between the manifold and pressure generation chambers with optimal orientation. The curvature prevents air bubbles from collecting in the flow path by ensuring continuous liquid flow, thus resolving the contradiction between configuration freedom and flow velocity maintenance.
2Reliability
If the flow path portion and bifurcation flow path portions communicate with same direction component to prevent air bubble collection, then air bubble discharge properties are improved, but the arrangement of head main body is limited
Solution Approach 1:
The patent employs a curved upstream-side flow path portion with a radius of curvature of 0.5mm or more to achieve both reliable air bubble discharge and flexible head arrangement. The curved geometry ensures that ink flows smoothly from the manifold to the bifurcation flow paths without creating dead zones where air bubbles could collect, while simultaneously allowing the flow path to be oriented in various directions to accommodate different head main body arrangements.
Solution Approach 2:
The patent changes the geometric parameters of the flow path, specifically setting the radius of curvature to 0.5mm or more, to optimize both air bubble discharge and arrangement flexibility. This parameter adjustment transforms the flow path from a rigid straight configuration to a flexible curved one that can adapt to different spatial requirements while maintaining optimal flow characteristics for air bubble elimination.
Data Source
AI summary
A bifurcation path and a flow path which communicates with the head main body through the bifurcation path are provided. The bifurcation path includes an upstream-side path and a downstream-side path. In a plan view of a flow-path forming surface including the bifurcation path and the flow path, the flow path is disposed in a state where an angle between a flowing direction in the flow path and a flowing direction in the downstream-side path is an acute angle. In addition, an angle between a first wall surface of the flow path, which is the wall surface located downstream from the upstream-side path, and a second wall surface of the upstream-side path, which is the wall surface connected to the first wall surface, is equal to or less than 90°. Furthermore, the second wall surface of the upstream-side path has an R shape.