Liquid Ejection Head Unit Residual Vibration Determination
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Solution Overview
Problem
Existing liquid ejection apparatuses using piezoelectric elements for ink ejection suffer from insufficient determination accuracy of the ejection unit state due to limitations in detecting residual vibrations.
Innovation Solution
The apparatus includes a head unit with an ejection unit driven by a piezoelectric element, a waveform shaping circuit to process residual vibration signals, and a determination circuit that uses shaped residual vibration signals and an offset value to accurately determine the ejection unit state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a piezoelectric element is driven to eject ink, then liquid ejection is achieved, but residual vibration occurs that reduces determination accuracy of the ejection unit state
Solution Approach 1:
The patent extracts the residual vibration signal from the overall system response by using a waveform shaping circuit that specifically processes signals in the frequency range corresponding to residual vibration (typically 20-100 kHz). This separation allows the determination circuit to analyze only the relevant vibration components without interference from other system responses, thereby improving measurement precision while addressing the harmful residual vibration effect.
Solution Approach 2:
The waveform shaping circuit acts as an intermediary between the piezoelectric element and the determination circuit. It processes the raw signal by amplifying and filtering the residual vibration components, converting them into a form suitable for accurate state determination. This intermediary processing stage eliminates the harmful effect of residual vibration on measurement accuracy by transforming it into useful diagnostic information.
2Measurement precision
If residual vibration signal is detected to determine ejection unit state, then state determination is enabled, but determination accuracy is insufficient
Solution Approach 1:
The patent implements a feedback mechanism where the determination circuit continuously monitors the waveform-shaped residual vibration signal and uses it to adjust or validate the ejection unit state determination. This feedback loop enhances both determination accuracy and reliability by continuously comparing expected vibration patterns with actual measurements, allowing for more reliable state assessment.
Solution Approach 2:
The waveform shaping circuit performs preliminary processing of the residual vibration signal before it reaches the determination circuit. By pre-amplifying and filtering the signal in advance, the system ensures that the determination circuit receives optimized input data, thereby improving both accuracy and reliability of the final state determination without requiring complex processing in the determination stage.
3Measurement precision
If waveform shaping circuit processes residual vibration signals, then signal processing capability is improved, but device complexity increases
Solution Approach 1:
The waveform shaping circuit is designed to perform multiple functions within a single integrated structure: amplification, filtering, and signal conditioning for residual vibration detection. By combining these functions into one multi-functional module, the patent improves signal processing capability while minimizing the increase in device complexity compared to using separate circuits for each function.
Solution Approach 2:
The patent merges the amplification and filtering functions into a single waveform shaping circuit module that processes residual vibration signals. This consolidation reduces the overall circuit complexity while maintaining enhanced signal processing capabilities, as the combined circuit performs multiple operations that would otherwise require separate components.
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 proposed solution enhances the determination accuracy of the ejection unit state by effectively processing residual vibration signals, leading to improved operational reliability and ink ejection precision.
Implementation Method 1
an ejection unit that includes a piezoelectric element driven by a drive signal and is configured to eject a liquid in accordance with drive of the piezoelectric element
Implementation Method 2
the amplifier circuit is configured to output an offset voltage signal from the output terminal in a first state in which a first constant voltage signal is input to the first input terminal and a second constant voltage signal is input to the second input terminal, and output the second residual vibration signal from the output terminal in a second state in which the first residual vibration signal is input to the first input terminal
Data Source
AI summary
A head unit include an ejection unit for ejecting a liquid, a waveform shaping circuit to which a first residual vibration signal corresponding to a residual vibration is input, and which outputs a second residual vibration signal, and a determination circuit, wherein an amplifier circuit provided to the waveform shaping circuit outputs an offset voltage signal in a first state in which a first constant voltage signal is input to a first input terminal and a second constant voltage signal is input to a second input terminal, and outputs the second residual vibration signal in a second state in which the first residual vibration signal is input to the first input terminal, and the second constant voltage signal is input to the second input terminal, and the determination circuit determines the state of the ejection unit based on the second residual vibration signal and an offset value.