Printhead Semi-Permeable Membrane Air Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing printheads face challenges in maintaining consistent droplet formation and print quality due to air bubbles and temperature variations in the print fluid, which affect jetting characteristics.
Innovation Solution
The enhanced printhead design includes a semi-permeable membrane to remove air from the supply manifold and a dual manifold structure with a primary and secondary duct to ensure consistent temperature of the print fluid, allowing air removal and temperature regulation before reaching the jetting channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional supply manifold is used without air removal mechanisms, then the printhead structure remains simple, but air bubbles remain in the print fluid affecting jetting characteristics
Solution Approach 1:
The supply manifold is segmented into a first supply manifold and a second supply manifold, with the first manifold receiving print fluid and the second manifold supplying it to jetting channels. This segmentation allows insertion of a heater between the manifolds and facilitates air bubble removal through structured fluid flow paths, improving jetting consistency without excessive complexity.
Solution Approach 2:
A heater is introduced as an intermediary component between the first and second supply manifolds. This heater serves as a thermal mediator that warms the print fluid to reduce viscosity and improve flow consistency, thereby enhancing jetting reliability while adding a controlled level of device complexity.
2Reliability
If print fluid temperature is not controlled, then the printhead structure remains simple, but jetting characteristics vary due to temperature fluctuations
Solution Approach 1:
The heater is positioned to preheat the print fluid in the first supply manifold before it reaches the jetting channels. This preliminary thermal action ensures the fluid achieves optimal temperature and viscosity characteristics prior to jetting, maintaining consistent jetting properties throughout operation.
Solution Approach 2:
The heating system operates continuously to maintain print fluid at the optimal temperature throughout the printhead's operational lifecycle. This continuous thermal action ensures consistent fluid viscosity and jetting characteristics, preventing temperature-related variations in print quality.
3Productivity
If high jetting frequencies are used for productivity, then printing speed increases, but air bubbles are more likely to be induced into the print fluid
Solution Approach 1:
The structured dual-manifold design enables extraction and removal of air bubbles from the print fluid through controlled flow paths. The first supply manifold acts as a separation zone where air bubbles can rise and be removed before the fluid enters the second manifold and reaches the jetting channels, preventing air-induced jetting failures during high-speed operation.
Solution Approach 2:
The heater modifies the physical parameters of the print fluid by increasing its temperature, which reduces viscosity and surface tension. These parameter changes make the fluid more resistant to air bubble formation and facilitate bubble removal, enabling stable high-frequency jetting for improved productivity.
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
This design results in more consistent droplet formation and higher print quality by removing air bubbles and ensuring uniform temperature across the printhead, leading to improved jetting reliability and productivity.
Implementation Method 1
a semi-permeable membrane disposed between the cavity and the supply manifold. As the print fluid flows through the supply manifold, air in the print fluid is able to escape through the semi-permeable membrane and into the cavity, while the print fluid is contained in the supply manifold by the semi-permeable membrane
Implementation Method 2
A vacuum may be applied to the cavity to assist in drawing the air from the print fluid and through the semi-permeable membrane
Implementation Method 3
Temperature of the print fluid in the printhead may affect the jetting characteristics, so it is therefore desirable to control the temperature of the print fluid within a printhead
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A printhead for jetting a print fluid, comprising a main body configured to attach to a stack of plates, where the stack of plates forms a row of jetting channels configured to jet droplets of a print fluid. The main body includes a supply manifold configured to provide a fluid path for the print fluid to the row of jetting channels, a cavity, and a semi-permeable membrane disposed between the cavity and the supply manifold.