Print Head Switching for Piezoelectric Ejection and Vibration Detection
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Solution Overview
Problem
Existing liquid ejection apparatuses, such as inkjet printers, face challenges in detecting residual vibrations of piezoelectric elements efficiently, which affects the accuracy of determining the state of the ejector.
Innovation Solution
The solution involves a print head and liquid ejection apparatus that includes a first pressure chamber, a nozzle communicating with the pressure chamber, a piezoelectric element generating residual vibration signals, a switch circuit to control the supply of drive signals to the piezoelectric element, and a residual vibration detection circuit to output signals corresponding to the residual vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a piezoelectric element is driven to eject ink, then liquid ejection is achieved, but residual vibration is generated that affects detection accuracy
Solution Approach 1:
The patent segments the detection process into two distinct phases: a drive period when the piezoelectric element is actively driven for ink ejection, and a detection period when residual vibration is measured. The switch circuit divides the operation into these separate time windows, allowing the same piezoelectric element to serve both ejection and detection functions without interference. This temporal segmentation resolves the contradiction by ensuring that detection occurs only when the drive signal is inactive, eliminating drive signal interference from the measurement.
Solution Approach 2:
The patent applies preliminary action by performing the ink ejection drive before the residual vibration detection. The switch circuit is configured to first supply the drive signal to eject ink, then immediately transition to the detection phase to measure residual vibration. This sequential arrangement ensures that the ejection action is completed before measurement begins, allowing the system to capture the natural decay of residual vibration without interference from ongoing drive signals.
2Reliability
If residual vibration detection is performed after piezoelectric element drive, then ejector state determination is enabled, but detection speed is insufficient
Solution Approach 1:
The patent maintains continuity of useful action by immediately transitioning from the drive period to the detection period without idle time. The switch circuit is configured to automatically switch from supplying drive signals to measuring residual vibration as soon as the drive signal stops. This continuous operation ensures that detection begins at the optimal moment when residual vibration is still strong, maximizing detection speed while maintaining reliable ejector state determination.
Solution Approach 2:
The patent implements feedback by using the detected residual vibration signal to immediately determine the ejector state. The detection circuit captures the residual vibration waveform and feeds this information back to the control system, which then determines whether the ejector is functioning normally or requires maintenance. This rapid feedback loop enables real-time monitoring and quick response to ejector issues, improving both detection speed and reliability.
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 the detection speed and accuracy of residual vibrations, allowing for better determination of the ejector's state, thereby improving the overall performance and reliability of the liquid ejection apparatus.
Implementation Method 1
a piezoelectric element configured to output a residual vibration signal according to residual vibration generated due to a volume change of the pressure chamber
Data Source
AI summary
A print head includes: a first pressure chamber whose volume changes according to a drive signal; a first nozzle communicating with the first pressure chamber and configured to allow a liquid to be ejected; a first piezoelectric element configured to output a first residual vibration signal; a first switch circuit having one end to which the drive signal is input and the other end electrically coupled to the first piezoelectric element, and configured to switch whether to supply the drive signal to the first piezoelectric element; and a first residual vibration detection circuit configured to output a first residual vibration detection signal corresponding to the first residual vibration signal, in which the first residual vibration detection circuit has one end electrically coupled to the one end of the first switch circuit and the other end electrically coupled to the other end of the first switch circuit.