Liquid Ejection Head Parasitic Oscillation Suppression
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Solution Overview
Problem
Liquid ejection heads experience parasitic oscillations with frequencies higher than the main acoustic resonance frequency, leading to residual oscillations and deteriorated print quality, which existing techniques fail to adequately suppress.
Innovation Solution
A liquid ejection head design incorporating a drive waveform with at least two stages of potential change in the cancellation waveform to cancel parasitic oscillations, where the pressure chamber is expanded and contracted in a controlled manner to align the phases of parasitic oscillations and suppress them effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cancellation waveform is input to suppress residual oscillation, then residual oscillation is suppressed, but parasitic oscillation occurs
Solution Approach 1:
The patent applies the principle of converting harm into benefit by using parasitic oscillation, which was previously considered a harmful effect, as a useful tool. Specifically, the drive waveform is designed to intentionally generate parasitic oscillation at frequencies higher than the main acoustic resonance frequency, and these parasitic oscillations are timed to cancel out residual oscillation in the pressure chamber, thereby achieving beneficial suppression of unwanted oscillations.
Solution Approach 2:
The patent applies parameter changes by modifying the drive waveform characteristics, specifically by setting the rise time and fall time of the drive waveform to specific values (0.05 μs to 0.5 μs). This parameter optimization enables the generation of parasitic oscillation with appropriate amplitude and frequency characteristics that can effectively cancel residual oscillation without causing harmful effects.
2Manufacturing precision
If rise time or fall time of drive waveform is adjusted to control meniscus oscillation, then satellite droplets are suppressed, but residual oscillation occurs
Solution Approach 1:
The patent applies preliminary anti-action by designing the drive waveform with specific rise time and fall time parameters (0.05 μs to 0.5 μs) that preemptively control meniscus oscillation to prevent satellite droplet formation. Additionally, the waveform includes a cancellation component that acts in advance to suppress residual oscillation before it can cause harmful effects, thereby addressing both issues proactively.
3Manufacturing precision
If cancellation waveform is used to suppress residual oscillation, then print quality improves, but power consumption increases
Solution Approach 1:
The patent applies partial action by using a simplified cancellation waveform approach that achieves sufficient residual oscillation suppression without applying excessive energy. The drive waveform parameters (rise time and fall time between 0.05 μs to 0.5 μs) are optimized to provide just enough cancellation effect to improve print quality while avoiding unnecessary power consumption that would result from more aggressive cancellation methods.
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 solution effectively suppresses parasitic oscillations, improving print quality by ensuring that the parasitic oscillations cancel each other out, thereby enhancing the ejection process and reducing power consumption.
Implementation Method 1
oscillation having a frequency higher than a main acoustic resonance frequency of liquid in the pressure chamber
Implementation Method 2
parasitic oscillation having a frequency higher than a main acoustic resonance frequency of liquid in the pressure chamber and generated by inputting the cancellation waveform
Data Source
AI summary
In an embodiment, a liquid ejection head includes a nozzle plate, a pressure chamber, an actuator, and a drive circuit. The actuator varies a volume of the pressure chamber in response to a driving signal from the drive circuit. The driving signal includes an ejection waveform for ejecting liquid from a nozzle and a cancellation waveform for suppressing residual oscillation after ejection of the liquid. The ejection waveform includes voltage changes in stages and the cancellation waveform also includes voltage changes in stages for suppressing residual oscillations and higher harmonic acoustic resonance frequencies.