Print Head Piezoelectric Element Low Pass Filter Circuit
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Solution Overview
Problem
In ink jet printers, unintended electric charges accumulate on piezoelectric elements due to leakage currents or noise, leading to unstable voltages, unintended displacements, and potential cracks in vibration plates, affecting ink ejection accuracy.
Innovation Solution
A print head design incorporating a low pass filter circuit in parallel with the switch circuit to stabilize the electric potential of piezoelectric elements, preventing unintended displacements and maintaining accurate ink ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a switch circuit is used to control drive signal supply to the piezoelectric element, then power consumption is reduced and control efficiency is improved, but voltage instability occurs due to leakage current and noise accumulation
Solution Approach 1:
A low pass filter circuit is introduced as an intermediary component between the switch circuit and the piezoelectric element. The filter circuit mediates the drive signal by removing high-frequency noise components while preserving the control signal, thereby stabilizing the voltage supplied to the piezoelectric element without compromising the switch circuit's power-saving function
Solution Approach 2:
The harmful high-frequency noise and leakage current components are extracted and removed from the drive signal through the low pass filter circuit. This separates the useful control signal from the harmful noise, allowing the switch circuit to maintain its control efficiency while the filter eliminates the voltage instability caused by leakage current
2Loss of energy
If the switch circuit is controlled to be in non-conduction state to save power, then power consumption is reduced, but unintended electric charges accumulate on the piezoelectric element
Solution Approach 1:
The low pass filter circuit serves as a protective intermediary that blocks the accumulation of unintended electric charges during the non-conduction state. By filtering out high-frequency noise and leakage current components, it prevents charge buildup on the piezoelectric element while allowing the switch circuit to remain in the power-saving non-conduction state
Solution Approach 2:
The leakage current that would normally cause harmful charge accumulation is converted into a beneficial filtering effect. The low pass filter circuit utilizes the electrical characteristics to transform the harmful leakage current into a means of stabilizing the voltage by attenuating high-frequency noise components
3Device complexity
If the piezoelectric element is unintentionally displaced due to voltage instability, then the vibration plate is stressed and cracks may occur, but the switch circuit operation remains simple
Solution Approach 1:
The low pass filter circuit acts as a protective intermediary that shields the vibration plate from unintended stress. By stabilizing the voltage supplied to the piezoelectric element, it prevents unintended displacement that would otherwise cause excessive stress and potential cracking of the vibration plate
Solution Approach 2:
The low pass filter circuit provides beforehand cushioning by preemptively filtering out noise and leakage current before they can cause unintended piezoelectric element displacement. This preventive measure protects the vibration plate from stress concentration and potential cracking before the damage occurs
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 reduces voltage instability and unintended displacements of piezoelectric elements, minimizing the risk of vibration plate cracks and maintaining high ink ejection accuracy.
Implementation Method 1
a piezoelectric element that includes a first electrode supplied with a drive signal and a second electrode supplied with a reference voltage signal and is displaced by a difference in electric potential between the first electrode and the second electrode
Implementation Method 2
A print head design incorporating a low pass filter circuit in parallel with the switch circuit to stabilize the electric potential of piezoelectric elements
Data Source
AI summary
A print head includes a piezoelectric element that includes a first electrode supplied with a drive signal and a second electrode supplied with a reference voltage signal and is displaced by a difference in electric potential between the first electrode and the second electrode, a cavity that is filled with a liquid ejected from a nozzle along with the displacement of the piezoelectric element, a vibration plate that is disposed between the cavity and the piezoelectric element, a switch circuit that switches between supplying and not supplying the drive signal to the first electrode, and a low pass filter circuit that is electrically connected in parallel with the switch circuit.