Liquid Discharging Head Non-Circular Descender Air Bubble Removal
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Solution Overview
Problem
Conventional liquid discharging heads face difficulties in easily discharging air bubbles from the nozzle, leading to inefficient bubble removal and increased channel resistance.
Innovation Solution
The liquid discharging head features a descender with a non-circular cross-section and return throttle channels connected to the sides of the minor axis, allowing for a shorter distance between the nozzle and return throttle channels, facilitating easy air bubble discharge and reducing channel resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the return throttle channel is connected to the descender with a conventional quadrangular cross-section, then the structure is simple and easy to manufacture, but the air bubble cannot be easily discharged from the nozzle
Solution Approach 1:
The descender is designed with an asymmetric non-circular cross-section (oval, rectangular, or triangular shape) instead of a symmetric circular cross-section. This asymmetric geometry creates preferential flow paths that facilitate air bubble movement toward the return throttle channel, improving air discharge performance while maintaining manufacturing simplicity through standard molding techniques.
2Loss of energy
If the return throttle channel is positioned far from the nozzle, then the channel resistance is reduced, but the air bubble discharge performance deteriorates
Solution Approach 1:
The patent utilizes the depth direction (vertical dimension) to position the return throttle channel. By connecting the return throttle channel to the side surface of the descender in the depth direction rather than only in the planar direction, the channel resistance is reduced while maintaining effective air bubble discharge performance through three-dimensional spatial arrangement.
3Productivity
If the descender has a circular cross-section, then the flow is uniform and manufacturing is easy, but the air bubble discharge efficiency is low
Solution Approach 1:
The descender employs a non-circular asymmetric cross-section (oval, rectangular, or triangular) to enhance air bubble discharge efficiency. The asymmetric geometry creates flow patterns that promote air bubble movement toward the return throttle channel, significantly improving discharge efficiency compared to conventional circular cross-sections.
4Ease of operation
If the return throttle channel is connected at the center of the descender, then the structure is symmetric and simple, but the air bubble discharge distance is too long
Solution Approach 1:
The return throttle channel is asymmetrically positioned by connecting it to the side surface of the descender rather than at the center. This asymmetric arrangement shortens the distance air bubbles must travel to reach the return channel, significantly improving discharge ease and efficiency while maintaining structural simplicity.
Data Source
AI summary
There is provided a liquid discharging head including: a pressure chamber configured to apply a pressure to a liquid so as to discharge the liquid from a nozzle; a descender arranged to overlap, in a plan view, with the nozzle and communicating the pressure chamber and the nozzle with each other; at least one return throttle channel connected to the descender; and a return manifold which communicates with the at least one return throttle channel and which is configured to receive the liquid not having been discharged from the nozzle. A cross section of the descender orthogonal to a depth direction of the descender is a non-circular shape having a major axis and a minor axis. The at least one return throttle channel is connected to at least one of a first end side of the minor axis and a second end side of the minor axis.