Fluid Ejection Device Circulation System
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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, pigment-ink vehicle separation, and viscous ink plug formation, which negatively impact print quality and nozzle health.
Innovation Solution
The implementation of a fluid circulation system within the inkjet printing system, where fluid is recirculated through fluid ejection chambers using integrated actuators, reducing decap time and managing air bubbles to prevent blockages and clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If inkjet nozzles remain uncapped and exposed to ambient conditions, then device simplicity is maintained, but ink blockage and clogging occur due to pigment settling and evaporation
Solution Approach 1:
The system performs preliminary circulation of ink through the nozzles before actual printing operations, keeping the ink flow path clear and preventing pigment settling. This preliminary action maintains nozzle health without requiring complex cap mechanisms, resolving the contradiction between device simplicity and reliability.
2Reliability
If fluid circulation is implemented to prevent blockages, then nozzle health improves, but device complexity increases due to additional circulation components
Solution Approach 1:
The circulation pump serves multiple functions: it circulates ink to prevent blockages, manages air bubbles, and maintains ink flow during storage and printing operations. This multi-functionality improves nozzle health without requiring separate dedicated components for each function, thereby limiting the increase in device complexity.
Solution Approach 2:
The system uses the existing pressure differential and fluid dynamics to achieve circulation without requiring complex external pumping mechanisms. The ink circulates through the nozzles and back through gravity and pressure differentials, allowing the system to service itself and maintain nozzle health with minimal additional complexity.
3Reliability
If ink is recirculated through fluidic channels, then ink blockage is reduced, but energy consumption increases due to continuous circulation
Solution Approach 1:
The circulation pump operates periodically rather than continuously, activating ink circulation only when needed to prevent blockages during storage or between printing sessions. This periodic operation maintains ink flow stability while significantly reducing overall energy consumption compared to continuous circulation.
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 effectively reduces ink blockage and clogging, improves nozzle health, minimizes ink consumption, and enhances print quality by maintaining ink stability and efficiency.
Implementation Method 1
a thermal resistor to vaporize liquid in a fluid ejection chamber to generate a bubble that ejects fluid drops from a nozzle
Implementation Method 2
a piezoelectric actuator to generate an electric field that deflects a membrane to eject fluid drops from a nozzle
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A fluid ejection device includes a fluid slot, a fluid ejection chamber communicated with the fluid slot, a drop ejecting element within the fluid ejection chamber, a fluid circulation channel communicated at one end with the fluid slot and communicated at another end with the fluid ejection chamber, a fluid circulating element within the fluid circulation channel, and a channel wall separating the fluid ejection chamber and the fluid circulation channel. The fluid circulation channel includes a channel loop, and a width of the channel wall is based on a width of the channel loop and a width of the fluid ejection chamber.