Passive One-Way Valve Ink Jet Purging Gravity
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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 high pressures, preventing the necessary pressure from being built up, and existing solutions require active actuators or pumps to manage the valve and ink flow.
Innovation Solution
An ink jet device with a passive one-way valve at the lower end of the ink supply line, which closes when the pressure in the reservoir reaches a predetermined value, allowing the supply line to be shut off during purging and opening by gravity, eliminating the need for a pump and reducing capillary adhesion issues.
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 reliability of ink supply is improved, but the purging pressure cannot be built up because the ink filter functions as a hydraulic lock at high pressures
Solution Approach 1:
The patent divides the ink supply system into two separate functional components: an ink filter for contaminant removal and a valve for pressure control. The valve is positioned downstream of the filter, allowing the filter to remain in place while the valve independently manages the purging pressure buildup by closing off the supply line when necessary.
Solution Approach 2:
The valve acts as an intermediary element between the ink filter and the ink reservoir. It mediates the interaction by closing off the supply line to the reservoir when purging pressure is required, preventing the filter from being overwhelmed by high pressure while still allowing filtered ink to flow during normal operation.
2Stress or pressure
If a tilt valve is used at the upper wall of the ink reservoir to shut off the ink supply line during purging, then the purging pressure can be built up, but the device complexity increases due to the actuator and moving parts
Solution Approach 1:
Instead of positioning the valve at the upper wall of the reservoir as in prior art, the patent inverts the arrangement by placing the valve at the lower end of the ink supply line. This inversion allows the valve to be actuated by the weight of the ink itself, eliminating the need for external actuators and complex moving parts while still achieving the same purging pressure buildup function.
Solution Approach 2:
The valve mechanism is designed to be self-actuating through the weight of the ink. When purging is required, the ink weight automatically closes the valve to shut off the supply line, and when purging is complete, the same weight opens the valve to restore ink flow, eliminating the need for external actuators.
3Ease of operation
If the valve is opened by gravity force of melted ink, then the valve opens automatically during normal operation, but the opening may be suppressed by capillary forces causing the ink supply line to be blocked
Solution Approach 1:
The patent applies different quality characteristics to different parts of the valve system. The valve seat and valve element are designed with specific surface properties and dimensional characteristics that optimize the balance between gravity-driven opening and capillary force resistance. The local geometry at the valve opening is specifically engineered to ensure reliable operation.
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 purging pressure buildup within the ink reservoir without a pump, preventing ink filter break-through and simplifying the device construction by using gravity to open and close the valve, ensuring efficient ink circulation and preventing capillary adhesion.
Implementation Method 1
the valve 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 2
The ink supply line and the ink reservoir are 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 3
the valve element being freely movable between the valve seat and the cage, the mass of the valve element being greater than the mass of the liquid ink which is displaced by the valve element
Data Source
AI summary
An ink jet device with an ink reservoir and a jetting assembly, with an ink supply line 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 flowing ink, and a purging device adapted to apply a purging pressure to an inner space of the ink reservoir, wherein a passive one-way valve is arranged below a nominal minimal fill level (L) of the ink reservoir for blocking a connection of the ink supply line to the ink reservoir when a pressure within the ink reservoir is high enough but not required to be higher than the purging pressure.