Nozzle Sealing Mechanism for Ink Circulation Control
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Solution Overview
Problem
Existing liquid discharging apparatuses face issues with ink leakage and gas retention during the filling process, leading to waste and inefficient filling of nozzles in printing heads.
Innovation Solution
A liquid discharging apparatus with a sealing section that independently seals each nozzle, allowing for controlled liquid circulation and subsequent pressurization to remove gas, preventing leakage and ensuring complete filling while minimizing liquid waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pump for circulation is rotationally driven in a state where the nozzle surface is covered by the suction cap, then liquid can be circulated in the circulation flow path, but liquid may be leaked from nozzles depending on the flow velocity
Solution Approach 1:
The suction cap is divided into a cap body and a contact member that can independently contact and seal each nozzle. This segmentation allows individual nozzle sealing while maintaining circulation, preventing liquid leakage during the filling process.
Solution Approach 2:
The nozzles are sealed by the contact member before the circulation pump is activated. This preliminary sealing action prevents liquid from leaking during subsequent circulation operations, addressing the leakage issue proactively.
2Reliability
If the suction cap covers the nozzle surface to form a closed space, then suctioning can be performed, but gas may remain in the nozzles without moving to the opening end portion
Solution Approach 1:
The contact member is designed to be movable, allowing it to transition from a sealed position during circulation to a retracted position during suction. This dynamic adjustment enables gas to escape from nozzles during suction while maintaining sealing during circulation.
Solution Approach 2:
The system changes the state of the contact member between sealed and retracted positions depending on the operational phase. During circulation, the contact member seals nozzles; during suction, it retracts to allow gas escape, thus removing gas retention issues.
3Ease of operation
If the opening-closing valve is closed and the pump for ink circulation is stopped in a state where it does not block the first ink flow path, then the pump for suction can be driven, but the process complexity increases
Solution Approach 1:
The sealing function is extracted from the opening-closing valve and assigned to a dedicated contact member on the suction cap. This separation allows the opening-closing valve to remain open during suction while the contact member provides the necessary sealing, simplifying the control sequence.
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 apparatus effectively suppresses liquid waste and ensures thorough removal of gas from the nozzles, maintaining a high flow rate and preventing ink leakage during the filling process.
Implementation Method 1
a pumping section which is provided further on the opening end portion side on one side than the discharging head in the circulation path and is capable of pumping liquid such that liquid circulates in the circulation path
Implementation Method 2
a pressurization section capable of pressurizing the storage section; and a control-during-filling section which executes second control in which the pressurization section and the sealing section are controlled such that sealing of the plurality of nozzles by the sealing section is released while the storage section is pressurized by the pressurization section
Data Source
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AI summary
When filling a printing head (24) with ink, ink in a sub-tank (53) is circulated through a forward path port (69), a forward path (62), the printing head, a return path (64), a return path port (73), and the sub-tank by pumping ink from the forward path port side to the printing head side by a circulation pump (76) in a state where a plurality of nozzles is sealed by bringing a contact member (44) of a capping device (40) into contact with a nozzle formation surface. Thereafter, sealing of the plurality of nozzles by the capping device is released while pressurizing the sub-tank by a pressure adjusting device (80).