Offset Nozzle Liquid Discharge Head Bubble Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inkjet heads face issues with bubble entrainment and growth near nozzles, leading to pressure absorption and non-discharge events, as bubbles can hinder liquid ejection operations and are difficult to remove, especially in side shooter types where bubbles tend to get trapped.
Innovation Solution
The design positions the ejection nozzle offset from the center of the pressure chamber, allowing bubbles to move towards the common chamber for removal during actuator-driven operations, ensuring stable ink ejection by positioning the nozzle closer to the ink inflow side in non-circulation type heads and closer to the discharge side in circulation type heads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the nozzle is positioned at the center of the pressure chamber, then liquid discharge symmetry is improved, but bubble removal becomes difficult and non-discharge events increase
Solution Approach 1:
The nozzle is deliberately positioned asymmetrically within the pressure chamber, specifically at an offset location rather than at the center. This asymmetric positioning creates a flow path geometry where liquid naturally moves away from the nozzle toward the open end of the pressure chamber, enabling bubbles to be carried outward and removed efficiently. The asymmetric design resolves the contradiction by sacrificing perfect discharge symmetry to achieve reliable bubble removal and prevent non-discharge events.
Solution Approach 2:
Instead of positioning the nozzle at the center for optimal symmetry, the invention inverts the conventional approach by placing the nozzle at an offset position. This inversion allows the pressure differential created during operation to naturally drive both liquid and bubbles toward the open end of the pressure chamber, where bubbles can escape. The inverted positioning transforms the bubble removal problem into a solution where bubbles are actively directed outward by the flow pattern.
2Ease of operation
If the nozzle is offset towards the ink inflow side in non-circulation type heads, then bubble escape is facilitated, but pressure distribution may be affected
Solution Approach 1:
The nozzle positioning is optimized for the specific operational mode of the inkjet head. In non-circulation type heads, the nozzle is positioned toward the ink inflow side to maximize bubble escape capability in that local region. This local optimization creates a favorable flow pattern where bubbles generated at the nozzle are immediately carried toward the open end by the natural flow direction, facilitating easy bubble removal without requiring complex pressure management systems.
Solution Approach 2:
The invention adjusts the nozzle position parameter based on the circulation type of the inkjet head. For non-circulation types, the nozzle is positioned closer to the inflow side, while for circulation types, it may be positioned differently to optimize performance. This parameter adjustment allows the system to adapt to different operational configurations, maintaining both bubble escape capability and acceptable pressure distribution characteristics for each specific head type.
3Reliability
If bubbles are present in the pressure chamber, then pressure absorption occurs leading to non-discharge events, but bubble removal mechanisms increase device complexity
Solution Approach 1:
The inkjet head design enables self-service bubble removal through its geometric configuration. The offset nozzle positioning and pressure chamber geometry work together to create a natural flow pattern that automatically carries bubbles toward the open end during normal operation. This self-service mechanism eliminates the need for additional active bubble removal components such as pumps, valves, or control systems, maintaining device simplicity while ensuring reliable discharge by preventing bubble accumulation.
Solution Approach 2:
The design extracts bubbles from the pressure chamber through its geometric configuration. By positioning the nozzle offset and designing the pressure chamber with an open end, the system creates a flow path that naturally extracts bubbles from the liquid stream and directs them toward the open end where they can escape. This passive extraction mechanism removes bubbles without requiring complex active removal systems, maintaining discharge reliability while keeping the device simple.
Data Source
AI summary
According to one embodiment, a liquid discharge head includes a pressure chamber and a nozzle. The pressure chamber extends in a first direction from a first end to a second end and forms a flow path for a fluid to be ejected from the nozzle. The nozzle is for ejecting liquid from the pressure chamber in a second direction intersecting the first direction. The nozzle is at a position offset from a midpoint of the pressure chamber in the first direction towards one of the first or second ends of the pressure chamber.