Fluid Height Backpressure System for Printhead Ink Supply
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing off-carrier fluid supply systems for thermal inkjet printers face challenges in maintaining backpressure without adding complexity or restricting the location of the ink supply tank, especially as devices become smaller.
Innovation Solution
A fluid height backpressure system utilizing a backpressure device with first and second chambers, an air removal device, and ink sensors to establish and maintain backpressure, allowing for flexible ink supply location and preventing air bubbles in the ink reservoir.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a passive fluid height backpressure system is used, then the system is simpler and uses less complexity, but the ink supply tank must be positioned at a specific height below the printhead, limiting location flexibility
Solution Approach 1:
The backpressure device is divided into multiple chambers (first chamber for ink supply, second chamber for backpressure generation) that can independently function. This segmentation allows the system to maintain backpressure through fluid height differences without requiring the ink tank to be positioned at a specific height, thereby achieving location flexibility while maintaining relative simplicity.
Solution Approach 2:
The backpressure device acts as an intermediary component between the ink supply tank and the printhead. It generates backpressure through fluid height in its chambers and delivers ink to the printhead, decoupling the location requirement of the ink tank from the printhead position. This intermediary mechanism provides location flexibility without adding complex pressure regulation systems.
2Adaptability or versatility
If an onboard pressure regulation system is used, then location flexibility is improved, but system complexity and cost increase
Solution Approach 1:
The backpressure device uses the weight of the ink fluid itself to generate backpressure through gravitational force acting on the fluid height in its chambers. This self-service mechanism eliminates the need for external pressure regulation systems, motors, or complex control electronics, thereby maintaining location flexibility while avoiding the complexity and cost of active pressure regulation systems.
3Stress or pressure
If spring loaded diaphragms are used to add backpressure, then backpressure can be added, but complexity and cost increase
Solution Approach 1:
The patent replaces mechanical spring-loaded diaphragm systems with a purely gravitational/fuid-static system. Backpressure is generated by the weight of the ink fluid column in the backpressure device chambers rather than by mechanical springs, eliminating moving mechanical parts, wear issues, and associated complexity while maintaining effective backpressure.
4Stress or pressure
If air is present in the fluid supply system, then air bubbles may be introduced into the ink reservoir, but proper backpressure cannot be maintained
Solution Approach 1:
The backpressure device includes a dedicated first chamber that separates the ink supply path from the backpressure generation path. Air can be present in the first chamber without being introduced into the second chamber or the printhead, as the chambers are separated by flow control mechanisms. This extraction of air from the critical path maintains ink delivery quality while allowing the system to function with air present in the supply system.
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 system effectively maintains backpressure even with an empty ink supply tank, ensures ink delivery without air bubbles, and allows for flexible placement of the ink supply tank, enhancing printer performance and reducing complexity.
Implementation Method 1
The air removal device is operable to enable periodically removing some air from the second chamber to maintain backpressure therein for drawing fluid from the first chamber into the second chamber
Implementation Method 2
The first and second chambers are connected in flow communication with each other by an outlet of the first chamber that opens into the second chamber such that fluid can drop downward from the outlet through the second chamber to the fluid in the second chamber
Data Source
AI summary
A fluid height backpressure system includes a printhead, a fluid supply tank, a backpressure device, and an air removal device. The backpressure device responsible for supplying system backpressure includes a tower disposed in an upright position and having a plurality of walls defining first and second chambers for respectively communicating with the ink supply tank and a fluid supply reservoir of the printhead. The air removal device provides additional backpressure in the second chamber, allows backpressure in the system to be maintained even with an empty fluid supply tank, and also supply of ink to the fluid supply reservoir of the printhead substantially without air bubbles being introduced therein. Also, ink sensors are utilized for sensing out-of-ink/ink-low conditions and also to help establish and continue the operation of the backpressure device.