Piezoelectric Inkjet Waveform Control for Residual Vibration Detection
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Solution Overview
Problem
Ink jet printers face issues with ink ejection abnormalities due to thickened ink, bubbles, or paper dust, leading to degraded image quality, and existing methods for inspecting the ejection state without ejecting ink are prone to ink staining and require precise waveform settings, which can be disrupted by changes in ink viscosity or temperature.
Innovation Solution
A printing apparatus with a piezoelectric element, pressure chamber, and nozzle system that uses a detection unit to analyze residual vibration signals to determine the ejection state, and a decision unit to adjust the driving signal waveform to prevent ink ejection during inspection, allowing for accurate assessment even with changes in viscosity or temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the piezoelectric element is driven by a driving signal to inspect the ejection state without ejecting ink, then real-time detection is enabled and printing delays are prevented, but ink may be ejected and stain the recording medium if the waveform is not appropriately set
Solution Approach 1:
The system dynamically adjusts the driving signal waveform parameters (voltage amplitude, pulse width, frequency) based on detected ink properties such as viscosity and temperature. This ensures the piezoelectric element is driven to a degree that generates detectable residual vibration without exceeding the threshold that would cause ink ejection and staining.
Solution Approach 2:
The system employs a feedback mechanism where the detection unit monitors residual vibration signals from the piezoelectric element, and this information is used to adjust the driving signal waveform in real-time. The control unit modifies waveform parameters based on the detected ejection state and ink conditions, preventing ink staining while maintaining real-time detection capability.
2Object-affected harmful factors
If the driving signal waveform is set to prevent ink ejection during inspection, then ink staining is prevented, but the inspection accuracy may be reduced due to insufficient piezoelectric element activation
Solution Approach 1:
The system uses a dynamic driving signal waveform that adapts its parameters based on real-time detection of ink properties and ejection state. The waveform is not fixed but is continuously adjusted to maintain optimal activation of the piezoelectric element for detection purposes without causing ink ejection, thereby balancing inspection accuracy with staining prevention.
Solution Approach 2:
The driving signal is calibrated to provide partial activation of the piezoelectric element - sufficient to generate detectable residual vibration for inspection purposes, but deliberately kept below the threshold that would cause full ink ejection. This partial action enables effective detection while preventing harmful staining.
3Reliability
If the driving signal waveform is adjusted to accommodate changes in ink viscosity or temperature, then inspection reliability is maintained across varying conditions, but the system complexity increases
Solution Approach 1:
The system incorporates sensors that detect ink properties such as viscosity and temperature, and this information feeds back to the control unit which automatically adjusts the driving signal waveform parameters. This feedback loop maintains inspection reliability across varying conditions without requiring manual intervention or complex mechanical adjustments.
Solution Approach 2:
The system replaces complex mechanical adjustment mechanisms with electronic control of the driving signal waveform. By using software-based waveform generation and adjustment, the system achieves adaptability to varying ink conditions without adding mechanical complexity, maintaining reliability through digital parameter modification rather than physical system changes.
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
Enables real-time detection of ejection abnormalities without ink ejection, maintaining image quality and preventing printer delays by accurately determining the ejection state through waveform adjustments, ensuring reliable operation across varying ink conditions.
Implementation Method 1
a piezoelectric element that is displaced according to a driving signal
Implementation Method 2
detects residual vibration generated by allowing the piezoelectric element to be driven by the driving signal
Data Source
AI summary
A printing apparatus includes an ejection unit including a piezoelectric element that is displaced according to a driving signal, and a nozzle capable of ejecting the liquid; a driving signal supply unit that supplies the driving signal; a detection unit that detects change of an electromotive force of the piezoelectric element; a determination unit that determines an ejection state of the liquid in the ejection unit based on the detection result of the detection unit; and a decision unit that is capable of performing a first process of deciding a waveform of the driving signal for inspection such that the liquid is not ejected from the nozzle when the driving signal for inspection is supplied to the piezoelectric element and a second process of correcting the waveform decided in the first process and deciding the corrected waveform as a waveform of the driving signal for inspection.