Ink Reservoir Variable Volume Structure Constant Pressure
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Solution Overview
Problem
Conventional inkjet printers face challenges in maintaining a constant ink pressure at the nozzles as the ink level in the reservoir decreases, leading to inefficiencies and potential ink leakage, especially with reciprocating printheads that require frequent scanning and are slow for full-color or photo-quality printing.
Innovation Solution
An ink reservoir with a sealed storage volume and a variable volume structure, such as an air bag, that expands as ink is drawn, maintaining a constant head and pressure at the nozzles, ensuring efficient ink usage and minimizing leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If ink is drawn from the reservoir without compensation, then ink is consumed and the reservoir empties, but the ink level and pressure at the outlet decrease leading to inconsistent ink flow
Solution Approach 1:
The air inlet valve is configured to open in advance when the ink level reaches a predetermined position, allowing air to enter the reservoir before the ink is completely depleted. This preliminary action maintains pressure balance and prevents ink leakage while ensuring continuous ink flow to the printhead.
Solution Approach 2:
Air is introduced as an intermediary substance into the ink reservoir to replace the volume of consumed ink. The air inlet valve controls the introduction of air, which compensates for the decreasing ink level and maintains constant hydrostatic pressure at the outlet, ensuring consistent ink flow without leakage.
2Quantity of substance
If the ink level in the reservoir decreases, then more ink can be consumed, but the hydrostatic pressure at the nozzles becomes unstable causing ink leakage
Solution Approach 1:
The system incorporates a feedback mechanism where the ink level in the reservoir is monitored, and the air inlet valve responds by opening when the ink level reaches a predetermined position. This feedback control ensures that air is introduced at the optimal moment to maintain constant hydrostatic pressure, preventing ink leakage while maximizing ink capacity.
3Manufacturing precision
If a reciprocating printhead is used to achieve full-color or photo-quality printing, then print quality improves, but printing speed decreases due to frequent scanning
Solution Approach 1:
The ink reservoir system automatically regulates its own pressure by introducing air when the ink level decreases, without requiring external intervention or complex pressure control mechanisms. This self-service pressure regulation ensures stable ink flow to the printhead, enabling high-quality printing at improved speeds by eliminating pressure-related interruptions.
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 solution maintains a consistent ink pressure and level, enhancing print quality and speed, particularly with pagewidth printheads, by preventing ink bulging and leakage, and optimizing ink usage by minimizing residual ink in the cartridge.
Implementation Method 1
a variable volume structure in the ink storage volume for expanding as ink is drawn through the ink outlet to keep a constant head of ink above the outlet valve
Implementation Method 2
maintaining a constant head and pressure at the nozzles
Data Source
AI summary
An ink reservoir for a printer with an inkjet printhead, the ink reservoir comprising: a sealed ink storage volume; an ink outlet for sealed fluid communication between the printhead and the ink storage volume; and, a variable volume structure in the ink storage volume for expanding as ink is drawn through the ink outlet to keep a constant head of ink above the outlet valve.