Sealed Ink Circulation System for Print Devices
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Solution Overview
Problem
Inkjet printers face issues with ink drying out and dust contamination due to open connections to the atmosphere, leading to decreased print quality and meniscus instability caused by pressure changes with temperature and humidity variations.
Innovation Solution
A print device that performs circulation operations in a sealed state, with varying circulation times and pump speeds based on elapsed time, temperature, and humidity to prevent sedimentation and maintain ink flowability, while keeping the supply and circulation paths closed to the atmosphere to prevent drying and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the container is open to the atmosphere through a through-hole to maintain atmospheric pressure during agitation, then ink circulation is enabled, but the ink dries out and dust enters the container
Solution Approach 1:
The patent applies the inert atmosphere principle by sealing the ink container and circulation system to create a closed environment isolated from the atmosphere. This prevents ink drying out and dust contamination while enabling ink circulation through a sealed pump system. The circulation pump operates within the sealed container, moving ink through circulation paths without requiring atmospheric pressure equalization holes.
2Object-affected harmful factors
If the circulation flow path is sealed to prevent drying and contamination, then ink protection is improved, but pressure becomes less than atmospheric pressure making meniscus maintenance difficult
Solution Approach 1:
The patent applies feedback by implementing pressure sensors that continuously monitor the internal pressure of the sealed container and circulation system. When pressure drops below atmospheric pressure, the control unit activates a pressure adjustment mechanism (such as a small vent valve or pressure equalization pump) to restore pressure to the appropriate level, thereby maintaining stable menisci in the nozzles while keeping the system sealed.
3Stability of the object's composition
If circulation operation is performed frequently to prevent sedimentation, then ink flowability is maintained, but the system complexity and operation time increase
Solution Approach 1:
The patent applies periodic action by implementing scheduled circulation operations that run at predetermined intervals rather than continuously. The control unit is programmed to activate the circulation pump at specific time intervals (e.g., every few hours or days) to prevent pigment sedimentation. This periodic operation maintains ink flowability while minimizing system complexity and 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 reduces sedimentation, maintains ink flowability, and prevents meniscus instability, thereby enhancing print quality and extending the life of the printer's inkjet nozzles.
Implementation Method 1
a circulation pump that circulates ink in a circulation flow path
Implementation Method 2
a temperature detection portion that can detect the temperature of at least part of the liquid in the liquid supply path
Implementation Method 3
a first pressure supply unit provided on the second flow path, a second pressure supply unit
Data Source
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AI summary
When a processor (11) of a print device (1) determines that an elapsed time since a circulation operation of a liquid is not less than a fixed time and does not determine that the elapsed time is not less than a first time, the processor performs a first circulation operation that circulates the liquid in a state in which a supply flow path (711 to 714) and a circulation flow path (731 to 734) are not open to the atmosphere. When the processor determines that the elapsed time is not less than the fixed time, is not less than the first time, and is less than a second time, the processor performs a second circulation operation that agitates the liquid more than the first circulation operation does. Therefore, the print device is able to agitate the liquid in accordance with the time that has elapsed since the circulation operation was last performed.