Liquid Jet Apparatus Modulation Period Control
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Solution Overview
Problem
In liquid jet printing apparatuses, using digital power amplifiers for drive signal amplification results in power loss and requires a large heat sink, and short modulation periods lead to inaccurate drive signals due to the switching elements' inability to respond to short pulses, compromising the follow-up property of the drive waveform signal.
Innovation Solution
A liquid jet apparatus with a modulation period modification circuit that adjusts the modulation period based on the drive waveform signal data, using a pair of push-pull coupled switching elements in a digital power amplifier, and a low pass filter to smooth the amplified signal, ensuring accurate drive signals are produced while maintaining follow-up property.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If pulse modulation is executed with a short modulation period to improve follow-up property of the drive signal to the drive waveform signal, then the response speed to the drive waveform signal is improved, but extremely short on-duty or off-duty pulses are generated that cause the switching element to fail to respond accurately, degrading manufacturing precision of the drive signal
Solution Approach 1:
The patent applies dynamics by making the modulation period variable rather than fixed. The modulation period is dynamically adjusted based on the instantaneous amplitude of the drive waveform signal. When the amplitude is large, a shorter modulation period is used to improve response speed. When the amplitude is small, a longer modulation period is used to prevent generation of excessively short pulses that the switching element cannot respond to. This dynamic adjustment resolves the contradiction between response speed and drive signal accuracy.
2Manufacturing precision
If the modulation period is made longer to prevent generation of extremely short pulses that the switching element cannot respond to, then the accuracy of the drive signal is improved, but the follow-up property to the drive waveform signal is degraded
Solution Approach 1:
The patent applies parameter changes by modifying the modulation period parameter according to the drive waveform signal characteristics. Specifically, the modulation period is changed based on the amplitude level of the drive waveform signal. This parameter adjustment allows the system to adapt to different signal conditions, ensuring accurate pulse generation while maintaining adequate response speed to the drive waveform signal.
3Loss of energy
If digital power amplification is used to reduce power loss and eliminate the heat sink, then energy efficiency is improved and device size is reduced, but the switching elements cannot respond to extremely short pulses, compromising drive signal accuracy
Solution Approach 1:
The patent applies preliminary anti-action by preemptively adjusting the modulation period before extremely short pulses are generated. By monitoring the drive waveform signal amplitude and adjusting the modulation period in advance, the system prevents the generation of pulses that the switching elements cannot respond to. This proactive approach allows digital power amplification to be used efficiently while avoiding the accuracy problems that would otherwise occur with short pulses.
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 prevents short pulses that the switching elements cannot respond to, ensuring accurate drive signals are output while maintaining the follow-up property of the drive waveform signal, enhancing the performance of liquid jet printing apparatuses.
Implementation Method 1
a piezoelectric element is used as the actuator
Data Source
AI summary
A liquid jet apparatus according to the present invention includes a drive waveform generator adapted to generate a drive waveform signal, a modulator adapted to execute pulse modulation on the drive waveform signal, a digital power amplifier adapted to power-amplify the modulated signal, on which the pulse modulation is executed by the modulator, with a pair of switching elements push-pull coupled with each other, a low pass filter adapted to smooth the amplified digital signal obtained by the power-amplification of the digital power amplifier, and a modulation period modification circuit adapted to modify a modulation period of the pulse modulation of the modulator based on data of the drive waveform signal.