Current Signal Transmission for Noise-Resistant Liquid Ejection
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Solution Overview
Problem
Existing liquid ejecting apparatuses face challenges in generating accurate drive waveform signals due to noise disturbances in the transmission path, leading to inaccurate liquid ejection control.
Innovation Solution
A liquid ejecting apparatus comprising a control unit with digital and analog signal generation units, a current signal generation unit, and a head unit with a voltage signal generation unit that detects and amplifies potential differences to produce a drive waveform signal resistant to noise, using a transmission unit that transmits current signals differentially to reduce noise influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a small amplitude voltage signal is transmitted from the control unit to the head unit through a cable, then the power consumption in the cable is reduced, but the signal becomes susceptible to noise disturbances in the transmission path
Solution Approach 1:
The patent replaces the conventional voltage signal transmission method with a current signal transmission method. Instead of transmitting a small amplitude voltage signal that is susceptible to noise, the system transmits a current signal whose magnitude corresponds to the waveform of the analog voltage signal. This substitution of the transmission medium (from voltage to current) resolves the contradiction by making the signal less susceptible to noise while maintaining low power consumption characteristics.
Solution Approach 2:
The patent changes the parameter of the transmitted signal from voltage to current. By converting the analog voltage signal to a current signal with corresponding waveform magnitude, and then converting it back to voltage at the receiving end, the system achieves noise-resistant transmission. This parameter transformation allows the signal to maintain integrity during transmission through the cable while consuming minimal power.
2Temperature
If a voltage waveform signal with small amplitude is transmitted to the head unit, then the heat in the cable is reduced, but it becomes difficult to precisely control the amount of liquid ejecting due to noise influence
Solution Approach 1:
The patent substitutes the voltage signal transmission system with a current signal transmission system. By transmitting current signals instead of voltage signals through the cable, the system reduces heat generation in the cable while the current signal's immunity to noise ensures precise control of the liquid ejection amount. The piezoelectric element responds accurately to the converted voltage signal despite the transmission through the cable.
Solution Approach 2:
The patent introduces an intermediary conversion process: the analog voltage signal is first converted to a current signal for transmission, then converted back to a voltage signal at the head unit. This intermediary current signal acts as a mediator that protects the signal from noise disturbances during transmission while maintaining the ability to precisely control the piezoelectric element and thus the liquid ejection amount.
3Reliability
If a current signal is transmitted instead of a voltage signal, then the signal becomes resistant to noise disturbances, but additional conversion circuits are required
Solution Approach 1:
The patent merges the signal conversion functions into integrated circuits within the control unit and head unit. The analog voltage signal generation unit and current signal generation unit are combined in the control unit, while the voltage signal generation unit is integrated in the head unit. This merging reduces the overall system complexity despite requiring conversion circuits, as the conversions are performed within existing control and processing units rather than requiring separate dedicated conversion devices.
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 enables the generation of accurate and resistant drive waveform signals, ensuring precise liquid ejection control by suppressing noise-induced malfunctions and distortion, thereby improving the reliability of the liquid ejecting process.
Implementation Method 1
a method of ejecting liquid from the head unit by applying a drive waveform signal to an element such as a piezoelectric element which is provided in the head unit, and by vibrating the piezoelectric element
Data Source
AI summary
A liquid ejecting apparatus including, a control unit including a digital signal generation unit which generates a digital signal defining the shape of the signal waveform, an analog voltage signal generation unit which generates an analog voltage signal on the basis of the digital signal, and a current signal generation unit which generates a current signal of a magnitude corresponding to a waveform of the analog voltage signal, a head unit including, a voltage signal generation unit which generates a voltage signal by detecting a potential difference between two points which are different from each other in a path to which the current signal flows, and by amplifying the potential difference, and an element which is driven by the voltage signal, and causes liquid to be ejected from a nozzle, and a transmission unit which transmits the current signal to the head unit from the control unit.