Switchable Feedback Damping for Piezoelectric Drop-on-Demand Ejection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Piezoelectric fluid-ejection devices face issues with residual resonance after ejecting a fluid drop, leading to unpredictable ejection of subsequent drops, affecting print quality due to incomplete damping by traditional tickle pulses.
Innovation Solution
Employing a drive and sense circuit that switches between feed-forward driving and feedback damping modes, using a compensation circuit to optimally dampen resonance by feeding back the output signal and adjusting it to counteract residual motion, ensuring precise control over the piezoelectric fluid-ejection mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional tickle pulses are used to dampen resonance, then some resonance reduction is achieved, but resonance damping is incomplete and slow, leading to unpredictable subsequent drop ejection
Solution Approach 1:
The patent implements a feedback damping mode where the sense circuit continuously monitors the piezoelectric actuator's motion and feeds this information back through the compensation circuit to the drive circuit. The drive circuit generates a feedback damping signal that is the negative of the sensed motion, actively counteracting residual resonance in real-time. This closed-loop feedback mechanism achieves complete and rapid resonance damping, ensuring predictable subsequent drop ejection within a short time frame.
2Reliability
If feedback damping mode is employed, then resonance is dampened completely and quickly, but device complexity increases due to additional circuit components
Solution Approach 1:
The patent designs a multi-functional drive and sense circuit that can operate in different modes (feed-forward driving mode and feedback damping mode) using the same basic circuit components. The circuit includes a drive circuit, sense circuit, and compensation circuit that work together in both normal drop ejection operation and resonance damping operation. This universal circuit design achieves complete resonance damping without proportionally increasing device complexity, as the same components serve multiple purposes.
3Productivity
If feed-forward driving mode is used, then drop ejection is simple and direct, but residual resonance interferes with subsequent drops, affecting print quality
Solution Approach 1:
The patent segments the operation into distinct phases: a feed-forward driving phase for rapid drop ejection, followed by a feedback damping phase to eliminate residual resonance. The control circuit switches between these phases, allowing the system to achieve both high productivity during drop ejection and high precision during the subsequent damping phase. This temporal segmentation enables the system to maintain fast ejection speeds while ensuring print quality through complete resonance elimination.
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 approach effectively reduces resonance more completely and quickly, ensuring consistent and predictable ejection of fluid drops, thereby improving print quality by minimizing interference from residual motion.
Implementation Method 1
In a piezoelectric fluid-ejection device, the piezoelectric effect is used to eject droplets of fluid. In particular, an electric field is induced within a flexible sheet of piezoelectric material to cause the sheet to physically deform.
Implementation Method 2
Employing a drive and sense circuit that switches between feed-forward driving and feedback damping modes, using a compensation circuit to optimally dampen resonance by feeding back the output signal and adjusting it to counteract residual motion
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A control circuit for a drop-on-demand piezoelectric fluid-ejection mechanism includes a drive and sense circuit, and a switch. The drive and sense circuit has an input, a drive output, and a sense output. The drive output is to be coupled to the drop-on-demand piezoelectric fluid-ejection mechanism. The switch is to switch the input of the drive and sense circuit between a feed-forward driving mode of the drive and sense circuit and a feedback damping mode of the drive and sense circuit. In the feed-forward driving mode, the switch is to couple the input to a drive waveform to cause the fluid-ejection mechanism to eject a drop of fluid. In the feedback damping mode, the switch is to couple the input to the sense output to dampen the fluid-ejection mechanism after the fluid-ejection mechanism has ejected the drop of fluid.