Liquid Ejecting Head Nozzle Geometry for Ink Circulation
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Solution Overview
Problem
Existing liquid ejecting systems face inefficiencies in replacing liquid near nozzles, leading to increased viscosity and clogging issues due to drying and component settling, affecting the performance and reliability of inkjet recording heads and other liquid ejecting systems.
Innovation Solution
A liquid ejecting head design featuring a first flow path between a supply port and a discharge port, with nozzles branching orthogonally, including a first nozzle portion for ink discharge and a second nozzle portion with a larger coupling port, enhancing ink circulation and flow speed to prevent viscosity increases and clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a branched flow path is provided in the vicinity of nozzles to circulate liquid, then liquid circulation is achieved to suppress viscosity increase, but liquid replacement efficiency near nozzles remains insufficient
Solution Approach 1:
The patent applies local quality by creating a localized circulation structure at the nozzle outlet. The circulation flow path is specifically positioned where liquid replacement is most needed, with the second opening (r2) larger than the first opening (r1) to enhance local flow velocity and replacement efficiency in the critical nozzle vicinity area.
Solution Approach 2:
The patent introduces a new dimensional approach by forming a three-dimensional circulation flow path that extends from the nozzle outlet backward into the liquid supply chamber. This spatial arrangement creates a circulation loop in multiple dimensions, allowing liquid to be replaced more effectively by moving it through a extended path rather than a simple planar flow.
2Reliability
If liquid circulates through the liquid ejecting head, then bubbles are discharged and component settling is suppressed, but ink flow speed and droplet flight speed need further improvement
Solution Approach 1:
The patent applies parameter changes by modifying the geometry parameters of the nozzle openings. Specifically, the second opening (r2) is made larger than the first opening (r1), creating a gradual expansion that optimizes flow velocity profiles. This geometric parameter adjustment enhances both the circulation flow speed and the droplet ejection speed while maintaining bubble discharge functionality.
3Productivity
If the second opening diameter r2 is larger than the first opening diameter r1, then liquid replacement efficiency improves, but nozzle structure complexity increases
Solution Approach 1:
The patent applies self-service by designing the circulation flow path to utilize the existing pressure differential and flow dynamics within the liquid ejecting head. The circulation path automatically draws liquid from the nozzle outlet and returns it to the supply chamber without requiring external pumps or complex control mechanisms, making the structure self-regulating and relatively simple despite the enhanced functionality.
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 design improves ink flow speed and droplet flight speed, reduces clogging and displacement errors, and maintains stable ink discharge by efficiently replacing liquid near nozzles, thereby enhancing the performance and reliability of liquid ejecting systems.
Implementation Method 1
a first flow path extending in a first axial direction between a supply port and a discharge port, and a nozzle that is provided to branch from the first flow path and that discharges a liquid along a second axial direction orthogonal to the first axial direction
Implementation Method 2
a diameter r2 of the second opening in the first axial direction is larger than a diameter r1 of the first opening in the first axial direction
Data Source
AI summary
A liquid ejecting head includes a first flow path extending in a first axial direction between a supply port and a discharge port, and a nozzle that is provided to branch from the first flow path and that discharges a liquid along a second axial direction orthogonal to the first axial direction. The nozzle includes a first nozzle portion in which a first opening for discharging the liquid is formed and a second nozzle portion in which a second opening that is a coupling port with the first flow path is formed, and a diameter r2 of the second opening in the first axial direction is larger than a diameter r1 of the first opening in the first axial direction.