Fluid Ejection Assembly Circulation Pump Ink Blockage
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Solution Overview
Problem
Inkjet printheads face issues with air bubbles and pigment-ink vehicle separation (PIVS) leading to ink blockage and clogging, which degrade print quality and increase costs, as existing solutions require servicing that consumes ink and delays printing.
Innovation Solution
A fluid ejection assembly with a fluid circulation pump asymmetrically located along the fluid channel to create directional flow, circulating fluid both horizontally and vertically through the channel and feed holes during idle and operational times to prevent blockage and clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional inkjet printhead is used without a circulation pump, then the device complexity is low, but ink blockage and clogging occur during storage and non-use periods
Solution Approach 1:
The circulation pump performs preliminary actions by circulating ink through the printhead during idle periods before actual printing occurs. This prevents pigment settling and air bubble formation in advance, ensuring reliable ink flow when printing resumes without requiring complex servicing procedures.
Solution Approach 2:
The printhead system performs self-service through the circulation pump that automatically circulates ink during non-printing periods. This self-maintenance function prevents blockage and clogging without requiring external servicing, reducing complexity compared to manual cleaning and priming systems.
2Reliability
If servicing is performed to clear blockages and clogging, then ink flow reliability is improved, but printing is delayed and ink is consumed
Solution Approach 1:
The circulation pump performs preliminary maintenance actions during idle periods, preventing blockage formation before it occurs. This eliminates the need for time-consuming servicing operations and ensures immediate printing readiness without delays.
Solution Approach 2:
The circulation pump maintains continuous useful action by constantly circulating ink through the printhead during storage and non-use periods. This continuous circulation prevents pigment settling and maintains ink flow reliability without interruption, eliminating downtime associated with servicing.
3Reliability
If servicing is performed to clear blockages and clogging, then ink flow reliability is improved, but ink consumption increases
Solution Approach 1:
The circulation pump performs preliminary prevention of blockage during idle periods, eliminating the need for ink-consuming servicing operations. By maintaining ink flow continuously, it prevents pigment settling and air bubble formation without requiring additional ink for cleaning and priming procedures.
Solution Approach 2:
The system performs self-maintenance through continuous circulation, preventing blockage without requiring external servicing that consumes ink. The circulation pump uses the existing ink supply to maintain flow, avoiding the additional ink consumption associated with manual cleaning and priming operations.
4Reliability
If pigment-based inks are used for durability and permanence, then print quality is improved, but pigment settling and PIVS occur during storage
Solution Approach 1:
The circulation pump performs preliminary action by continuously circulating pigment-based ink during storage periods. This prevents pigment particles from settling and crashing out of the ink vehicle before printing occurs, maintaining ink composition stability while preserving the durability and permanence benefits of pigment-based inks.
Solution Approach 2:
The circulation pump maintains continuous useful action by constantly moving pigment-based ink through the printhead during non-use periods. This continuous circulation prevents pigment settling and PIVS, maintaining ink composition stability without compromising the print durability and permanence that pigment-based inks provide.
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
The fluid circulation mechanism effectively prevents ink blockage and clogging, ensuring immediate printing and reducing the total cost of ownership by minimizing ink consumption during servicing.
Implementation Method 1
A fluid ejection assembly includes a fluid slot formed in a first substrate. The top surface of the first substrate is adhered to the bottom surface of a membrane, or second substrate. A channel is formed in a chamber layer disposed on top of the second substrate, and fluid feed holes are formed through the second substrate between the fluid slot and the channel. A fluid ejection element is located near a first end of the channel, and a pump element is located near a second end of the channel to circulate fluid horizontally through the channel and vertically through the fluid feed holes.
Data Source
AI summary
A fluid ejection assembly includes a fluid slot formed in a first substrate and a channel formed in a chamber layer disposed on top of a second substrate. The bottom surface of the second substrate is adhered to the top surface of the first substrate and fluid feed holes are formed between the fluid slot and the channel. A fluid ejection element is at a first end of the channel and a pump element is at a second end of the channel to circulate fluid horizontally through the channel and vertically through the fluid feed holes.