MEMS Membrane Ink Jet Printhead for Uniform Droplet Formation
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Solution Overview
Problem
Conventional continuous inkjet printing systems face issues with power dissipation and non-uniformity due to piezoelectric drive technology, which degrades over time and cycles, and thermal energy pulses result in significant power dissipation per break-off cycle.
Innovation Solution
A micro-electrostatic mechanical system (MEMS) membrane is used to break up the ink stream into uniform droplets, driven by a capacitive drive signal, reducing power dissipation and enabling higher nozzle densities through silicon wafer fabrication techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If piezoelectric drive technology is used to perturb the ink stream, then droplet formation is achieved, but non-uniformity and degradation issues occur over time and cycles
Solution Approach 1:
The patent replaces the piezoelectric mechanical drive system with an electrohydrodynamic system using electrodes positioned at the printhead orifices. This substitution eliminates the degradation issues associated with piezoelectric materials and their bonding to the diaphragm, while maintaining stable and uniform droplet formation through electrical field manipulation of the ink stream.
Solution Approach 2:
The patent changes the drive mechanism from mechanical piezoelectric actuation to electrical field-based electrohydrodynamic control. By adjusting electrical parameters (voltage, frequency) rather than mechanical properties, the system achieves consistent droplet uniformity without the degradation problems of piezoelectric materials over time and cycles.
2Manufacturing precision
If thermal energy pulses are used to break up the ink stream, then droplet formation is achieved, but significant power dissipation occurs
Solution Approach 1:
The patent replaces thermal energy pulse mechanisms with electrohydrodynamic electrodes that use electrical fields to perturb and break up the ink stream. This substitution eliminates the significant power dissipation associated with thermal methods, as the electrical field approach requires much less energy to achieve the same droplet formation effect.
3Productivity
If continuous stream ink jet printing is used, then high productivity is achieved, but power dissipation and complexity increase compared to drop-on-demand systems
Solution Approach 1:
The patent extracts and eliminates the ink recovering gutter and recirculation system from the continuous stream ink jet printer by implementing drop-on-demand droplet expulsion. This removal simplifies the system architecture and reduces the power dissipation associated with maintaining continuous ink flow and recirculation, while preserving high productivity through efficient direct droplet placement.
Solution Approach 2:
The patent implements periodic droplet expulsion only when needed, rather than maintaining continuous ink flow. This periodic action approach maintains high productivity by placing droplets exactly when required, while significantly reducing power dissipation by eliminating the continuous pumping and recirculation operations characteristic of traditional continuous stream systems.
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 MEMS-based solution stabilizes droplet formation with lower power requirements, allowing for increased nozzle density and reduced degradation, improving the efficiency and productivity of continuous inkjet printing systems.
Implementation Method 1
activating a drive signal to activate a micro-electrostatic mechanical system (MEMS) membrane
Data Source
AI summary
An embodiment relates generally to a method of ejecting ink. The method includes providing a continuous stream of ink from a pressurized fluid chamber and activating a drive signal to activate a micro-electrostatic mechanical system (MEMS) membrane. The method also includes stably breaking up the jet stream into uniform droplets in response to deflecting the MEMS membrane to perturb the continuous stream of ink.