Liquid Discharging Drive Circuit Modulation for Power and Accuracy
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Solution Overview
Problem
Existing liquid discharging apparatuses, such as ink jet printers, face challenges in accelerating image formation speed and improving discharge accuracy due to limitations in power consumption and drive signal output circuits, particularly with a large number of nozzles requiring significant current for piezoelectric elements.
Innovation Solution
A liquid discharging apparatus with a drive signal output circuit that includes a modulation circuit, amplification circuit, and demodulation circuit, utilizing capacitors with laminated structures (resin and metal thin film layers for one capacitor and ceramic and metal thin film layers for another) in parallel, to generate a drive signal that displaces between 25 V and a lower potential, optimizing capacitance and frequency characteristics for efficient ink discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large number of piezoelectric elements are used to increase the number of nozzles, then the liquid discharging apparatus can achieve higher image formation speed and better discharge accuracy, but the current required to operate the piezoelectric elements becomes very large, increasing power consumption
Solution Approach 1:
The patent changes the electrical parameters of the drive signal output circuit by introducing a modulation circuit that outputs a modulation signal at a higher frequency than the piezoelectric element driving frequency. This allows the use of a class D amplification circuit that consumes less power while still being able to drive the piezoelectric elements effectively through demodulation and filtering.
Solution Approach 2:
The patent introduces a modulation circuit as an intermediary between the control signal and the piezoelectric element drive circuit. This modulation circuit converts the base drive signal into a modulation signal that can be amplified more efficiently, then demodulated back to the correct frequency for the piezoelectric elements, thereby reducing power consumption while maintaining drive capability.
2Use of energy by moving object
If a class D amplification circuit is used to reduce power consumption, then power consumption is reduced, but the discharge accuracy and image formation speed are not sufficiently improved
Solution Approach 1:
The patent incorporates a feedback mechanism through the demodulation circuit that includes a capacitor connected in parallel with the inductor. This feedback path ensures that the output drive signal maintains the correct frequency and amplitude characteristics, thereby preserving discharge accuracy while using the power-efficient class D amplification circuit.
Solution Approach 2:
The patent carefully controls the frequency parameter of the modulation signal to be higher than the piezoelectric element driving frequency, and sets the capacitor value in the demodulation circuit to appropriately filter the signal. This parameter optimization allows the class D amplifier to operate efficiently while still delivering accurate drive signals to the piezoelectric elements.
3Productivity
If the drive signal frequency is increased to improve image formation speed, then image formation speed is improved, but capacitance fluctuations occur and waveform accuracy deteriorates
Solution Approach 1:
The patent introduces a modulation circuit as an intermediary that handles the frequency conversion. The modulation circuit outputs a modulation signal at a higher frequency, which is then amplified and demodulated back to the correct frequency for the piezoelectric elements. This intermediary approach allows high-frequency operation for speed improvement while maintaining waveform accuracy through proper frequency translation.
Solution Approach 2:
The patent changes the frequency parameter of the modulation signal to be higher than the piezoelectric element driving frequency, and sets the capacitor value in the demodulation circuit to appropriately filter the signal. This parameter optimization allows high-frequency operation for speed improvement while maintaining waveform accuracy through proper frequency translation and filtering.
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 configuration enhances both image formation speed and discharge accuracy by reducing capacitance fluctuations and maintaining waveform accuracy, even at high voltage and frequency, thereby improving the overall performance of the liquid discharging apparatus.
Implementation Method 1
a piezoelectric element that is driven based on the drive signal and discharges liquid by a drive of the piezoelectric element
Implementation Method 2
the first capacitor includes a first laminated portion in which a resin thin film layer and a first metal thin film layer are laminated, the second capacitor includes a second laminated portion in which a ceramic thin film layer and a second metal thin film layer are laminated, and an electrostatic capacitance of the first capacitor is larger than an electrostatic capacitance of the second capacitor
Data Source
AI summary
Provided is a liquid discharging apparatus including a modulation circuit, an amplification circuit, and a demodulation circuit that includes a first capacitor, a second capacitor, and an inductor and outputs the drive signal, one end of the first capacitor and one end of the second capacitor are coupled to one end of the inductor, the first capacitor and the second capacitor are coupled to each other in parallel, the first capacitor includes a first laminated portion in which a resin thin film layer and a first metal thin film layer are laminated, the second capacitor includes a second laminated portion in which a ceramic thin film layer and a second metal thin film layer are laminated, and the electrostatic capacitance of the first capacitor is larger than the electrostatic capacitance of the second capacitor.