Liquid Ejection Head Waveform Control for Residual Oscillation
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Solution Overview
Problem
Existing liquid ejection heads experience residual oscillation after liquid ejection, leading to satellite droplets that deteriorate print quality.
Innovation Solution
A liquid ejection head with a drive circuit that generates a driving signal comprising an ejection waveform for ejecting liquid and a cancellation waveform with a trapezoidal wave to suppress residual oscillation, using a piezoelectric actuator with alternating piezoelectric columns and non-driven columns to vary pressure chamber volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a drive waveform with adjusted rise time or fall time is used to control meniscus oscillation timing, then satellite droplets are suppressed, but residual oscillation occurs after liquid ejection
Solution Approach 1:
The patent applies preliminary anti-action by introducing a cancellation waveform that generates oscillation in the opposite phase to the residual oscillation caused by the ejection waveform. This cancellation waveform is designed to counteract and suppress the residual oscillation before it can cause satellite droplets, thereby resolving the contradiction between droplet ejection precision and residual oscillation suppression.
Solution Approach 2:
The patent uses periodic action by combining the ejection waveform with a cancellation waveform that has a specific period and frequency relationship. The cancellation waveform is timed to occur at critical moments in the oscillation cycle to suppress residual oscillation, while the ejection waveform maintains precise droplet ejection. This periodic combination allows simultaneous achievement of both droplet precision and oscillation suppression.
2Manufacturing precision
If a complex drive waveform is used to suppress residual oscillation, then print quality improves, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the drive waveform into two distinct components: an ejection waveform responsible for liquid ejection and a cancellation waveform responsible for suppressing residual oscillation. This segmentation allows each waveform to be independently optimized and controlled, simplifying the overall system design while achieving high print quality through the coordinated action of these two segmented waveforms.
3Speed
If the pressure chamber volume is varied rapidly to eject liquid, then ejection speed increases, but residual oscillation is enhanced
Solution Approach 1:
The patent applies preliminary action by applying a voltage to expand the pressure chamber volume before the ejection moment. This preliminary expansion prepares the liquid for ejection by reducing pressure and facilitating rapid ejection when the contraction occurs, while the subsequent cancellation waveform suppresses the residual oscillation that would otherwise be enhanced by the rapid volume variation.
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
Suppresses residual oscillation, improving print quality by reducing satellite droplets and enhancing the precision of liquid droplet ejection.
Implementation Method 1
an actuator configured to vary a volume of the pressure chamber in response to a driving signal
Implementation Method 2
a cancellation waveform that includes a trapezoidal wave for suppressing residual oscillation after the ejection of the liquid
Data Source
AI summary
A liquid ejection head includes a nozzle plate including a nozzle that ejects a liquid, a pressure chamber that communicates with the nozzle, an actuator configured to vary a volume of the pressure chamber in response to a driving signal, and a drive circuit configured to generate the driving signal. The driving signal includes an ejection waveform for ejecting the liquid and causing: an expansion potential difference for expanding the volume of the pressure chamber, a contraction potential difference for contracting the volume of the pressure chamber, and one or more intermediate potential differences between the expansion potential difference and the contraction potential difference, and a cancellation waveform that includes a trapezoidal wave for suppressing residual oscillation after the ejection of the liquid.