Liquid Ejecting Head Asymmetric Outlet Design for Bubble Removal
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Solution Overview
Problem
In liquid ejecting heads, air bubbles tend to stay inside the filter downstream chamber when the head is inclined, causing abnormal ink ejection due to blockage of the filter mesh, and existing solutions require different head configurations for various orientations, increasing costs and complexity.
Innovation Solution
The liquid ejecting head design includes a downstream chamber with multiple outlets positioned off-center, allowing air bubbles to exit regardless of the head's orientation, with the first and second outlets shifted from the chamber's center in opposite directions, facilitating bubble removal and simplifying maintenance across different installation orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the liquid ejecting head is inclined with respect to the horizontal plane, then the liquid can be ejected in the desired direction, but air bubbles will stay inside the filter downstream chamber at a portion that is above the opening, causing blockage
Solution Approach 1:
The downstream chamber is divided into multiple sections with separate outlets positioned at different locations. This segmentation ensures that air bubbles can exit through different outlets depending on their position, preventing blockage while maintaining proper liquid ejection direction.
Solution Approach 2:
The outlets are positioned asymmetrically within the downstream chamber rather than at the center. This asymmetric arrangement allows air bubbles to be effectively removed regardless of the head's inclination angle, as the outlets are strategically positioned to receive bubbles from various directions.
2Device complexity
If a single outlet is provided at the center portion of the filter downstream chamber, then the structure is simple, but air bubbles will accumulate above the opening when the head is inclined
Solution Approach 1:
The single outlet is segmented into multiple outlets positioned at different locations within the downstream chamber. This segmentation maintains structural simplicity while significantly improving air bubble removal effectiveness by providing multiple exit paths for bubbles.
Solution Approach 2:
The outlet configuration transitions from a single-point (0D) or linear (1D) arrangement to a distributed multi-point arrangement in two dimensions. This dimensional change allows air bubbles to be removed from various positions and directions, addressing the inclination problem effectively.
3Reliability
If different head configurations are provided for various orientations, then air bubble removal is effective for each orientation, but the cost and complexity increase
Solution Approach 1:
A single downstream chamber configuration with multiple outlets positioned at different locations serves multiple functions: it effectively removes air bubbles regardless of the head's inclination angle and maintains proper liquid ejection direction. This universal design eliminates the need for different head configurations for various orientations.
Solution Approach 2:
The asymmetric positioning of multiple outlets creates a universal solution that works for various orientations. The asymmetric arrangement ensures that regardless of which way the head is inclined, air bubbles will be directed toward one of the outlets for effective removal, eliminating the need for orientation-specific configurations.
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 effectively reduces air bubble retention and simplifies maintenance by ensuring air bubbles can exit through the outlets regardless of the head's orientation, preventing blockages and reducing the need for multiple head configurations, thus enhancing operational efficiency and cost-effectiveness.
Implementation Method 1
The filter is configured to filter the liquid that has flowed in through the inlet
Implementation Method 2
if the liquid ejecting head disclosed in JP-A-2018-043369 is used in an inclined state with respect to the horizontal plane, air bubbles will stay inside the filter downstream chamber at a portion that is above the opening
Data Source
AI summary
A liquid ejecting head includes: a nozzle face; a filter; a downstream chamber that includes a first outlet and a second outlet for discharging the liquid, the downstream chamber being located downstream of the filter; a first flow passage that is in communication with the downstream chamber through the first outlet; a second flow passage that is in communication with the downstream chamber through the second outlet; and a common flow passage that is in communication with the first flow passage and the second flow passage, wherein, as viewed perpendicularly to the nozzle face, the first outlet is located at a position that is shifted from a center of the downstream chamber in a first direction, and the second outlet is located at a position that is shifted from the center of the downstream chamber in a second direction that is opposite of the first direction.