Inkjet Fluid Circulation Prevents Nozzle Clogging
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Solution Overview
Problem
Inkjet printing systems face issues with ink blockage and clogging due to exposure to ambient conditions, leading to degradation in ink drop quality, including altered trajectories, velocities, shapes, and colors, as well as pigment-ink vehicle separation and viscous plug formation during storage or non-use.
Innovation Solution
The implementation of a fluid circulation system within the inkjet printing system, where fluid is circulated or recirculated through fluid ejection chambers using fluid circulating elements or actuators to prevent clogging and maintain ink quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If inkjet nozzles remain uncapped and exposed to ambient conditions during storage or non-use, then the system is simpler to operate, but ink blockage and clogging occur due to evaporation and pigment settlement
Solution Approach 1:
The system performs preliminary actions by automatically circulating ink through the nozzles and ejection chambers before decap effects can cause blockage. The controller activates circulation pumps or uses thermal/resonant actuators to move ink through the fluidic channels, preventing pigment settlement and evaporation-related clogging during storage periods.
Solution Approach 2:
The inkjet system serves itself by incorporating automatic ink circulation capability that operates without external intervention. The controller monitors storage conditions and automatically initiates ink circulation through integrated pumps or actuators, eliminating the need for manual uncapping/capping operations while maintaining nozzle health.
2Manufacturing precision
If thermal resistors or piezoelectric actuators are used to eject ink drops, then ink can be precisely deposited, but pigment particles settle and block ink flow to the ejection chambers during storage
Solution Approach 1:
The system maintains continuous or periodic ink circulation through the ejection chambers and fluidic channels during storage periods. This continuous action prevents pigment particles from settling and blocking the precise flow paths required for high-quality inkjet deposition, ensuring both precision and reliability are maintained.
Solution Approach 2:
The controller implements periodic ink circulation cycles during storage, activating pumps or actuators at regular intervals to redistribute pigment particles throughout the ink vehicle. This periodic action prevents blockage formation while maintaining the precision of the ejection system when printing operations resume.
3Reliability
If fluid circulation is implemented through fluidic channels with circulating elements, then ink blockage is reduced, but device complexity increases
Solution Approach 1:
The circulation system is designed with multi-functionality where the same fluidic channels and actuators serve both ink ejection and ink circulation functions. Thermal resistors and piezoelectric actuators used for drop ejection are also utilized to drive ink circulation during storage, eliminating the need for separate dedicated circulation components and reducing overall device complexity.
Solution Approach 2:
The patent merges the ink ejection function and ink circulation function into a unified system. The fluidic channels, actuators, and controller work together to perform both dropping and circulation operations, consolidating what could be separate systems into one integrated mechanism that reduces component count and simplifies the overall device architecture.
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 approach reduces ink blockage and clogging, improves nozzle health, minimizes pigment-ink vehicle separation, and enhances ink efficiency by maintaining ink quality and reducing consumption during servicing, while also managing air bubbles within the ejection chambers.
Implementation Method 1
fluid is circulated or recirculated through fluid ejection chambers using fluid circulating elements or actuators
Implementation Method 2
thermal resistors or piezoelectric material membranes as actuators within fluidic chambers to eject fluid drops
Implementation Method 3
thermal resistors or piezoelectric material membranes as actuators within fluidic chambers to eject fluid drops
Implementation Method 4
evaporation of water or solvent, can cause pigment-ink vehicle separation (PIVS) and viscous plug formation
Data Source
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AI summary
A fluid ejection device includes a fluid slot, a plurality of fluid ejection chambers communicated with the fluid slot, a plurality of drop ejecting elements one of each within one of the fluid ejection chambers, a plurality of fluid circulation channels each communicated with the fluid slot and one or more of the fluid ejection chambers, and a plurality of fluid circulating elements each communicated with one or more of the fluid circulation channels. The fluid circulating elements are to provide intermittent circulation of fluid from the fluid slot through the one or more of the fluid circulation channels and the one or more of the fluid ejection chambers.