Print Fluid Recirculation to Prevent Nozzle Drying
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Solution Overview
Problem
Conventional inkjet printing systems face issues with print fluid drying in printheads during non-printing operations, leading to nozzle clogging, print quality defects, and equipment damage, which necessitate frequent maintenance and downtime.
Innovation Solution
A print fluid recirculation system with a supply manifold, recirculation manifold, and recirculation pathway, utilizing vacuum sources and regulators to maintain a controlled and consistent flow of print fluid through printheads, reducing the need for spitting operations and printhead replacements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If print fluid is pushed through printheads during printing operations, then printing function is achieved, but print fluid does not circulate during non-printing operations causing nozzles to gulp air and residual fluid to dry out
Solution Approach 1:
The system implements continuous circulation of print fluid through the printheads even during non-printing operations using a recirculation pump and dedicated recirculation pathway. This ensures the fluid continuously flows through the nozzles, preventing air intake and drying out, thereby maintaining reliable printhead functionality without interruption.
Solution Approach 2:
The recirculation system performs preliminary action by continuously preparing the print fluid for ejection through constant circulation before actual printing occurs. This pre-circulation prevents the fluid from stagnating, gulping air, or drying in the nozzles, ensuring readiness for immediate printing when needed.
2Reliability
If spitting routines are performed to prevent drying of ink in nozzles, then nozzle clogging is reduced, but print fluid and consumables are consumed and printer downtime increases
Solution Approach 1:
Instead of periodic spitting routines that stop printing to clean nozzles, the system implements continuous recirculation that prevents clogging throughout operation. The pump continuously moves fluid through the printheads, and the recirculation pathway ensures fluid that doesn't eject during printing continues circulating rather than drying, eliminating the need for productivity-reducing maintenance stops.
Solution Approach 2:
The recirculation system enables the print fluid to self-maintain its flow properties through continuous movement. The fluid naturally prevents its own drying and clogging issues through the sustained circulation created by the pump and recirculation pathway, eliminating the need for external intervention via spitting routines.
3Reliability
If recirculation pathway is added to maintain continuous fluid flow, then printhead reliability is improved, but device complexity increases
Solution Approach 1:
The system segments the fluid pathway into distinct functional zones: a supply manifold for delivering fresh fluid, a recirculation manifold for collecting and returning fluid, and a dedicated recirculation pathway with a pump. This segmentation allows each component to perform its specific function efficiently while maintaining overall system reliability through organized fluid management.
Solution Approach 2:
The recirculation pump acts as an intermediary component that mediates between the supply and recirculation manifolds, actively moving fluid through the recirculation pathway. This intermediary element enables the complex recirculation function without requiring direct integration between all components, simplifying the overall system architecture while achieving the reliability goal.
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 system significantly reduces print quality issues and equipment damage by maintaining printhead functionality, minimizing maintenance, and enhancing printer uptime and customer satisfaction.
Implementation Method 1
A first vacuum source in fluid communication with the recirculation manifold is to cause application of a negative pressure to the recirculation manifold
Data Source
AI summary
In one example of the disclosure, a system for print fluid recirculation includes a supply manifold, a recirculation manifold, a printbar, and a recirculation pathway. The printbar includes a plurality of printheads that are in fluid communication with the supply manifold, and the recirculation manifold. The recirculation pathway is in fluid connection with the supply manifold and the recirculation manifold, and is to enable recirculation of print fluid at a controlled flow through the plurality of printheads.