Inkjet Drive Circuit Waveform Accuracy Power Efficiency
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Solution Overview
Problem
Existing drive circuits for inkjet printers, particularly those using piezoelectric elements, face limitations in waveform accuracy and power efficiency due to insufficient modulation and amplification of drive signals.
Innovation Solution
A drive circuit comprising a modulation circuit, an amplifier circuit, a level shift circuit, and a demodulation circuit, which includes gate drivers and transistors to generate and control a drive signal, employing a bootstrap circuit for voltage amplification and charge control to improve waveform accuracy and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional amplifier circuit is used to drive the piezoelectric element, then the drive signal can be amplified, but the waveform accuracy deteriorates due to insufficient modulation and amplification control
Solution Approach 1:
The drive circuit is divided into multiple independent functional modules: modulation circuit, amplifier circuit, level shift circuit, and demodulation circuit. Each module performs a specific function with dedicated transistors and control mechanisms, allowing precise control of the drive signal waveform while maintaining amplification capability.
Solution Approach 2:
The circuit employs dynamic control mechanisms where transistors are switched between conductive and non-conductive states based on control signals. The level shift circuit dynamically adjusts voltage levels, and the modulation circuit dynamically varies signal characteristics to maintain waveform accuracy during amplification.
2Reliability
If the piezoelectric element is driven with sufficient current, then the ejection performance is improved, but the power consumption increases
Solution Approach 1:
The drive circuit uses periodic modulation and demodulation cycles to generate the drive signal. The modulation circuit periodically varies the reference drive signal, and the demodulation circuit periodically recovers the amplified signal, enabling efficient power delivery only when needed for ink ejection.
Solution Approach 2:
The circuit changes electrical parameters dynamically: the modulation circuit varies frequency and amplitude of the reference signal, the amplifier circuit adjusts gain, and the level shift circuit modifies voltage levels. These parameter changes enable efficient power delivery while maintaining reliable ejection performance.
3Measurement precision
If the switching time of transistors is reduced, then the waveform accuracy is improved, but the charge storage stability deteriorates
Solution Approach 1:
The level shift circuit performs preliminary voltage level adjustment before the signal enters the demodulation circuit. By pre-establishing appropriate voltage levels and charge states, the circuit ensures stable charge storage while enabling rapid transistor switching for accurate waveform generation.
Solution Approach 2:
The level shift circuit acts as an intermediary between the amplifier circuit and demodulation circuit. It buffers and conditions the amplification modulation signal, providing stable charge storage while allowing fast switching in the demodulation stage to maintain waveform accuracy.
4Power
If the reference potential is shifted to a higher potential, then the amplification capability is improved, but the device complexity increases
Solution Approach 1:
The level shift circuit performs multiple functions: it shifts the reference potential to a higher level for improved amplification, stabilizes charge storage, and conditions the signal for demodulation. This multi-functionality reduces the need for separate circuits, managing complexity while achieving the desired amplification capability.
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 proposed drive circuit enhances waveform accuracy and reduces power loss by minimizing switching times and stabilizing charge storage, leading to improved operational stability and ink ejection precision.
Implementation Method 1
a bootstrap circuit to which a second voltage and the amplification modulation signal are input and which outputs a third voltage
Implementation Method 2
a piezoelectric element is provided in a head unit corresponding to each of a plurality of nozzles, and each of the piezoelectric elements is driven according to a drive signal. As a result, a predetermined amount of ink (liquid) is ejected from the nozzle
Data Source
AI summary
An amplifier circuit, a level shift circuit; and a demodulation circuit, in which in a second mode obtained by shifting a reference potential of the amplification modulation signal to a second potential having a potential higher than a first potential, the second gate driver included in the level shift circuit performs a constant voltage control that outputs a third gate signal controlling a third transistor to be conductive and a fourth gate signal controlling a fourth transistor to be non-conductive, and a charge control that outputs the third gate signal controlling the third transistor to be non-conductive and the fourth gate signal controlling the fourth transistor to be conductive, and then outputs the third gate signal controlling the third transistor to be conductive and the fourth gate signal controlling the fourth transistor to be non-conductive.