Air Flow-Restricting Members for Ink Cartridge Back Pressure
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Solution Overview
Problem
Fluid cartridges for inkjet printers face challenges in maintaining back pressure, leading to unwanted ink flow and color mixing due to unintended air entry through leak regions during construction, which can result in ink drooling and color contamination.
Innovation Solution
The introduction of air flow-restricting members adjacent to the air/ink exchange port constricts air flow, maintaining back pressure levels and preventing undesirable fluid flow through nozzles by compressing capillary media and restricting air paths, thereby ensuring consistent ink delivery and preventing color mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional air enters the air/ink exchange port from leak regions during construction, then the back pressure in the cartridge cannot be maintained, but the air/ink exchange port is necessary for air and ink communication between chambers
Solution Approach 1:
A hydrophobic coating is applied to the air/ink exchange port to act as an intermediary layer that selectively allows ink to pass through while blocking air. This coating mediates between the need for air/ink communication and the need to prevent air leakage, enabling the port to function as both a communication channel and a seal.
Solution Approach 2:
The surface properties of the air/ink exchange port are changed by applying a hydrophobic coating, which alters its permeability characteristics. The coating changes the port's ability to differentially transmit fluids based on their surface tension properties, allowing ink (higher surface tension) to pass while blocking air (lower surface tension).
2Reliability
If one cartridge fails to provide sufficient back pressure, then ink may drool out the nozzles onto the orifice plate, but increasing back pressure in one cartridge may cause ink to be drawn up by back pressure of another color cartridge
Solution Approach 1:
The air/ink exchange port is extracted from the wall structure and implemented as a separate, replaceable component. This allows the port to be independently optimized with hydrophobic coating technology, separating the back pressure maintenance function from the structural wall and enabling precise control of air/ink separation without affecting other cartridges.
Solution Approach 2:
The hydrophobic coating is applied locally to the air/ink exchange port surface, creating a localized region with specialized properties. This local modification enables selective fluid transmission at the port interface while leaving the rest of the cartridge structure unchanged, providing precise control over air and ink behavior at the critical exchange point.
3Ease of manufacture
If the air/ink exchange port is formed directly in the wall, then the structure is simple, but unintended air entry paths form during construction
Solution Approach 1:
The hydrophobic coating serves as an intermediary layer on the air/ink exchange port that selectively interacts with different fluids. It mediates between the simple wall-integrated port structure and the requirement to prevent air leakage, allowing the port to remain structurally simple while adding functional selectivity through the coating layer.
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 air flow-restricting members effectively regulate back pressure, preventing ink leakage and color contamination by restricting air entry, ensuring reliable ink flow and maintaining the desired capillary force for efficient inkjet printing.
Implementation Method 1
The back pressure within the free ink chamber of the cartridge is generally maintained by capillary force and the flow of air and/or ink back and forth through the air/ink exchange port.
Implementation Method 2
The introduction of air flow-restricting members adjacent to the air/ink exchange port constricts air flow, maintaining back pressure levels and preventing undesirable fluid flow through nozzles by compressing capillary media
Data Source
Figure 1~2
Figure 3A~3B
Figure 4~5
AI summary
A fluid cartridge (10) for a printing device includes a housing (12) having a base (14) and a first (24) and second (26) chamber. A wall (22) extends outwardly from and substantially normal to the base (14) and is configured to separate the housing (12), thereby forming the first (24) and second (26) chambers. An air/ink exchange port (32) is defined in a bottom portion of the wall (22) and adjacent to the base (14). A longitudinal air flow-restricting member (52) is disposed adjacent the air/ink exchange port (32) and on the base (14), and extends outwardly a predetermined distance into one of the first (24) or second (26) chambers.