Tankless Ink Recirculation for DOD Card Printing Throughput
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Solution Overview
Problem
DOD printing on plastic cards faces challenges in achieving durable, high-quality, and varied printing while maximizing card throughput, particularly with inks containing particulate materials, and existing systems require bulky recirculation tanks that are not easily removable.
Innovation Solution
A tankless recirculation system for ink delivery in DOD printing systems, utilizing a vessel that is disposed of after use, with ink recirculation through header tanks and a vacuum system to maintain particulate dispersion and ink quality, and direct pumping between header tanks and supply bottles for efficient ink management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a recirculation tank is used to maintain ink quality and particulate dispersion, then printing durability and quality are improved, but device complexity and space requirements increase
Solution Approach 1:
The patent extracts the recirculation function from a separate bulk tank system and integrates it directly into the header tank system. The header tanks serve dual purposes: storing ink and providing recirculation pathways, eliminating the need for dedicated recirculation tanks while maintaining ink quality and particulate dispersion through continuous circulation.
Solution Approach 2:
The header tanks are designed to perform multiple functions simultaneously: they store ink, facilitate recirculation, and maintain ink quality. The system uses the same vessels for both storage and recirculation purposes, reducing overall system complexity while achieving reliable printing through continuous ink circulation and particulate dispersion.
2Reliability
If a bulk recirculation tank is used to maintain ink quality, then printing quality is improved, but ease of operation and system flexibility are reduced
Solution Approach 1:
The system divides the recirculation function into multiple header tanks (first header tank and second header tank) that can operate independently or in conjunction with the supply bottle. This segmentation allows for flexible operation modes: direct pumping from supply bottle to print head, recirculation through header tanks, or combination approaches, enhancing ease of operation while maintaining quality.
3Stability of the object's composition
If ink is recirculated through header tanks, then particulate dispersion is maintained, but device complexity increases
Solution Approach 1:
The patent merges the recirculation system with the ink storage system by using header tanks that serve as both storage vessels and recirculation pathways. The vacuum system and pumping mechanism are integrated into this unified structure, maintaining particulate dispersion through recirculation while avoiding the complexity of separate dedicated recirculation tanks.
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
Enhances printing durability and quality on plastic cards, maintains particulate dispersion, and increases card throughput without the need for a separate recirculation tank, ensuring efficient ink utilization and system flexibility.
Implementation Method 1
a vacuum system that is fluidly connected to the first and second ink header tanks and that applies a vacuum to the drop-on-demand print head
Implementation Method 2
pumping ink directly from the ink supply bottle into the first ink header tank when the first ink header tank needs to be supplied with ink, and pumping ink from the second ink header tank directly into the ink supply bottle
Data Source
AI summary
DOD ink delivery systems and methods are described herein that are used in DOD card printing systems of card processing systems for supplying ink for DOD printing on plastic cards. The ink delivery systems are configured to recirculate the ink without using a recirculation tank separate from an ink supply. The ink can be recirculated back into the ink supply or, when the ink supply is not present, the ink can be recirculated from a return header tank to a supply header tank.