Liquid Supply Unit Pressure Segmentation for Ink Dripping
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Solution Overview
Problem
Conventional liquid supply units for inkjet printers face challenges in preventing unlimited dripping of ink from the discharge hole when supplied by water head difference, as they rely on negative pressure generation to control ink flow, which can lead to inefficiencies and potential clogging issues.
Innovation Solution
A liquid supply unit with a first and second chamber configuration, where the second chamber is set to negative pressure, utilizing a flexible film member and transmitting member to control the opening/closing of the communication opening between the chambers, ensuring stable ink flow and preventing backflow during different operational modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional liquid supply unit uses a flexible film and pressing plate to generate negative pressure in the pressure chamber, then unlimited dripping of ink is suppressed, but the structure becomes complex and unreliable due to direct pressing of the movable valve
Solution Approach 1:
The pressure chamber is divided into a first pressure chamber (communicating with the ink cartridge) and a second pressure chamber (communicating with the injection head), separated by a partition wall with a communication opening. This segmentation allows independent pressure control in each chamber, simplifying the overall structure while maintaining reliable ink flow control.
Solution Approach 2:
The flexible film and pressing plate mechanism is extracted from the second pressure chamber and relocated to the first pressure chamber. The communication opening in the partition wall serves as the valve mechanism, eliminating the need for a movable valve in the second chamber and reducing structural complexity.
2Reliability
If the negative pressure degree of the pressure chamber increases to prevent dripping, then ink flow control improves, but the risk of clogging increases and operation becomes less stable
Solution Approach 1:
Different pressure conditions are applied to different locations: the first pressure chamber maintains a higher pressure (lower negative pressure degree) to ensure stable ink supply, while the second pressure chamber maintains a lower pressure (higher negative pressure degree) to prevent dripping at the injection head. This local differentiation of pressure quality prevents both dripping and clogging.
Solution Approach 2:
The communication opening in the partition wall acts as an intermediary mechanism between the first and second pressure chambers. It allows controlled ink flow from the first chamber to the second chamber while maintaining the pressure differential, preventing direct exposure to excessive negative pressure that could cause clogging.
3Ease of operation
If a movable valve is used to control ink flow into the pressure chamber, then ink supply can be regulated, but the valve may fail or clog under varying pressure conditions
Solution Approach 1:
The movable valve is completely removed from the second pressure chamber. Instead, a fixed communication opening in the partition wall serves as the flow control mechanism, eliminating mechanical failure and clogging issues associated with movable valves while maintaining ease of operation through pressure differential control.
4Reliability
If the pressure chamber is sealed to maintain negative pressure, then ink flow control improves, but the system becomes less adaptable to different operating modes such as purge and decompression
Solution Approach 1:
The pressure chamber is segmented into two independently controllable chambers. The first chamber can be sealed to maintain stable pressure for normal operation, while the second chamber can be independently vented or pressurized to enable purge and decompression modes. This segmentation provides both reliability and adaptability.
Solution Approach 2:
The partition wall with the communication opening provides dynamic adaptability: during normal operation, the opening remains closed to maintain negative pressure; during purge mode, it can be opened to equalize pressure; during decompression, it allows controlled pressure adjustment. This dynamic behavior enables multiple operating modes while maintaining reliability.
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 configuration ensures stable and efficient ink supply to the liquid injection head, preventing dripping and clogging by dynamically adjusting the pressure in the second chamber, allowing for reliable operation during printing, pressurized purge, and decompression modes.
Implementation Method 1
The flexible film member defines a side surface of the second chamber facing the communication opening and is displaced based on a pressure change of the second chamber
Implementation Method 2
The transmitting member transmits a displacement force of the flexible film member to the opening/closing member in a direction opposite to a displacement direction of the flexible film member
Implementation Method 3
If a negative pressure degree of the pressure chamber increases due to the suction of ink by the liquid injection head
Implementation Method 4
The movable valve is biased in a direction opposite to a direction of the pressing by a biasing member
Data Source
AI summary
A liquid supply unit includes a first chamber, a second chamber, a wall portion, an opening/closing member, a flexible film member and a transmitting member. The wall portion includes a communication opening allowing communication between the first chamber and the second chamber. The opening/closing member changes a posture between a closing posture for closing the communication opening from the second chamber side and an opening posture. The flexible film member is displaced based on a pressure change of the second chamber. The transmitting member transmits a displacement force to the opening/closing member to be the opening posture when the second chamber is set to a negative pressure exceeding a predetermined threshold value, and transmits the displacement force to the opening/closing member to be the closing posture according to a displacement of the flexible film member when the second chamber is pressurized.