Tapered Ink Channel Bubble Management
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Solution Overview
Problem
In thermal inkjet printers, gas bubbles accumulating near the printhead can displace ink, causing the printhead to lose its prime and become useless, as existing technologies fail to effectively manage air and gas bubbles within the ink channels.
Innovation Solution
The design incorporates a print cartridge with ink channels featuring a taper tunnel and bubble tunnel configuration, utilizing buoyancy and surface tension forces to direct air bubbles away from the printhead, and a check valve to prevent air from re-entering the ink channels, ensuring efficient ink flow and bubble management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas bubbles are allowed to accumulate near the printhead, then the ink flow path is blocked and the printhead loses its prime, but attempting to remove bubbles increases device complexity
Solution Approach 1:
The patent extracts the harmful gas bubbles from the ink flow path by providing a dedicated escape path that leads bubbles away from the printhead and into a gas vent. This separates the bubble management function from the ink delivery function, maintaining printhead reliability without adding complex active control mechanisms.
Solution Approach 2:
The channel design uses the natural buoyancy of gas bubbles to automatically direct them away from the printhead through the tapered section and into the gas vent. The system serves itself by utilizing the inherent physical properties of the bubbles rather than requiring external actuators or control systems to remove them.
2Productivity
If the ink channel is designed with tapered walls to move bubbles away from the printhead, then bubble removal efficiency increases, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the geometric parameters of the ink channel by introducing a tapered section with gradually varying cross-sectional area. This parameter change creates the necessary flow dynamics to move bubbles away from the printhead while the taper angles are designed to be manufacturable within standard tolerances.
Solution Approach 2:
The channel design transitions from a simple linear path to a three-dimensional tapered structure that expands in cross-sectional area along the flow direction. This dimensional change provides additional flow paths and volume for bubble accommodation, improving removal efficiency without requiring extreme precision in any single dimension.
3Productivity
If high printing rates are maintained, then productivity increases, but gas bubbles accumulate more rapidly near the printhead
Solution Approach 1:
The patent ensures continuous bubble removal by providing an always-open escape path through the tapered channel and gas vent. This continuous action prevents bubble accumulation even during high-speed printing operations, maintaining ink flow stability and reliability throughout extended printing cycles.
Solution Approach 2:
The tapered channel acts as an intermediary structure between the ink supply and the printhead, providing a dedicated pathway that mediates the interaction between ink flow and gas bubbles. This intermediary allows high printing rates by decoupling the ink delivery function from the bubble management function.
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 configuration effectively moves air bubbles away from the printhead, preventing ink displacement and maintaining printhead functionality, even during high printing rates, by balancing buoyancy and drag forces within the channel design.
Implementation Method 1
The tapered channel walls create a buoyancy force that moves bubbles away from the printhead
Implementation Method 2
utilizing buoyancy and surface tension forces to direct air bubbles away from the printhead
Data Source
AI summary
In one embodiment, a fluid flow channel includes a first part and a second part connected to and positioned downstream from the first part such that fluid can flow from the first part to the second part. The first part has opposing sidewalls, a floor extending between the sidewalls, and a ceiling extending between the sidewalls. The ceiling of the first part slopes upward in an upstream direction or the sidewalls taper in toward one another in a downstream direction, or both. The second part has opposing sidewalls and a ceiling extending between the sidewalls. The ceiling of the second part slopes upward in an upstream direction.