Passive One-Way Valve for Ink Reservoir Purging
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Solution Overview
Problem
Existing ink jet devices face challenges in building up purging pressure within the ink reservoir without using a pump, as the ink filter can function as a hydraulic lock at normal pressures but fails to do so at higher purging pressures, leading to potential air or ink breakthrough and requiring active valve closure or capillary adhesion issues.
Innovation Solution
An ink jet device with a passive one-way valve located below the nominal minimal fill level of the ink reservoir, which allows ink to flow by gravity and automatically closes when the purging pressure is reached, ensuring the ink supply line is shut off during purging and opens again by gravity when pressure returns to normal, eliminating the need for a pump and preventing capillary adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an ink filter is provided at the ink supply line to prevent contaminants from entering the ink reservoir, then the ink reservoir is protected from contamination, but the ink filter cannot function as a hydraulic lock under high purging pressure, leading to potential breakthrough and inability to build up necessary purging pressure
Solution Approach 1:
The ink supply line is divided into two separate functional sections: an ink filter for contamination protection and a passive one-way valve for pressure control. This segmentation allows each component to perform its specific function independently - the filter protects against contaminants while the valve enables hydraulic lock effect under purging pressure, resolving the contradiction between contamination protection and pressure building capability.
Solution Approach 2:
A passive one-way valve is introduced as an intermediary component between the ink filter and the ink reservoir. This valve acts as a mediator that allows ink to flow into the reservoir during normal operation but prevents reverse flow under purging pressure, enabling the system to build up necessary purging pressure while maintaining contamination protection through the filter.
2Stress or pressure
If an active valve with actuator is used to close the ink supply line during purging operations, then the ink supply line can be shut off to build up purging pressure, but the device complexity increases due to additional actuators and moving parts
Solution Approach 1:
The passive one-way valve is designed to automatically respond to pressure changes without requiring external actuation. During purging operations, the valve self-closes when purging pressure is applied, and self-opens when normal operation resumes. This self-service mechanism eliminates the need for actuators and complex control systems, reducing device complexity while maintaining the ability to build up necessary purging pressure.
Solution Approach 2:
The active mechanical actuation system is replaced with a passive pressure-responsive valve mechanism. Instead of using motors, solenoids, or other active actuators to control the valve, the system uses the pressure differential itself to control valve operation. This substitution of active mechanical control with passive pressure-based control significantly reduces device complexity.
3Ease of operation
If the valve is arranged at the upper wall of the ink reservoir, then the valve can control ink flow, but capillary forces may suppress valve opening and block the ink supply line
Solution Approach 1:
Instead of positioning the valve at the upper wall where capillary forces would suppress opening, the passive one-way valve is inverted and positioned at the lower end of the ink supply line. This inversion places the valve in a position where gravity assists opening and capillary forces are minimized. The valve responds to pressure differential rather than relying on position-dependent capillary effects, eliminating the harmful capillary adhesion while maintaining effective flow control.
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
Enables reliable shut-off and opening of the ink supply line during purging operations without the need for a pump, preventing ink filter breakthrough and capillary adhesion, thus facilitating a simpler and more efficient ink jet device construction.
Implementation Method 1
the ink supply line and the ink reservoir being arranged to allow liquid ink to flow through the valve into the ink reservoir in accordance with and supported by gravity acting on the ink
Implementation Method 2
said valve being a passive one-way valve that is adapted to block the connection of the ink supply line to the ink reservoir when a pressure within the ink reservoir reaches a predetermined value
Implementation Method 3
the ink filter may function as a hydraulic lock, so that the negative pressure can be provided to the ink reservoir while at the same time ink may be supplied to the ink reservoir through the ink filter
Data Source
Figure 1~2
Figure 3
AI summary
Ink jet device with an ink reservoir (20) and a jetting assembly (10), with an ink supply line (28) being arranged to allow liquid ink (22) to flow through the valve (42) into the ink reservoir (20) in accordance with and supported by gravity acting on the flowing ink, and with a purging device (56) adapted to apply a purging pressure to an inner space (18) of the ink reservoir (20), wherein a passive one-way valve (42) is arranged below a nominal minimal fill level (L) of the ink reservoir (20) for blocking a connection of the ink supply line (28) to the ink reservoir (20) when a pressure within the ink reservoir (20) is high enough but not required to be higher than the purging pressure.