Piezoelectric Print Head Capacitance Detection Circuit
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Solution Overview
Problem
Existing print apparatuses face challenges in accurately measuring the capacitance of piezoelectric layers, which is crucial for estimating the temperature of the printing head, leading to potential inaccuracies in ink discharge and print quality.
Innovation Solution
A print apparatus is designed with a piezoelectric member, individual and common electrodes, and a detection circuit that includes an oscillation circuit to detect the capacitance of capacitors formed by these components, allowing for the measurement of capacitance differences that correlate with temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitance measurement is performed using existing methods, then temperature estimation can be obtained, but measurement precision is insufficient leading to inaccurate ink discharge control
Solution Approach 1:
The invention divides the capacitance measurement into two separate capacitors: a first capacitor formed between the individual electrode and first common electrode, and a second capacitor formed between the individual electrode and second common electrode. By measuring each capacitor separately and calculating the difference, the system achieves higher measurement precision and compensates for temperature-induced errors, thereby improving ink discharge accuracy.
Solution Approach 2:
The invention changes the measurement parameter from absolute capacitance value to capacitance difference between two capacitors. This parameter transformation allows the system to eliminate common-mode errors and focus on the relevant capacitance change, significantly improving measurement precision for temperature estimation and ink discharge control.
2Measurement precision
If a detection circuit is added to measure capacitance, then temperature estimation improves, but device complexity increases
Solution Approach 1:
The detection circuit is designed to perform multiple functions: it measures the capacitance of the first capacitor, measures the capacitance of the second capacitor, calculates the difference between them, and provides temperature estimation. By integrating these functions into a single circuit module, the invention improves temperature estimation accuracy without proportionally increasing device complexity.
Solution Approach 2:
The detection circuit automatically performs capacitance measurements and difference calculations without requiring external intervention. The circuit self-regulates the measurement process, reducing the need for additional control components and simplifying the overall system architecture while maintaining high measurement precision.
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 solution enables precise capacitance detection, improving temperature estimation and ink discharge accuracy, thereby enhancing print quality and reliability.
Implementation Method 1
a piezoelectric member configured to be deformed in order to discharge a liquid from a nozzle
Implementation Method 2
a detection circuit configured to detect a capacitance of a first capacitor configured by the piezoelectric member, the individual electrode, and the first common electrode and a second capacitor configured by the piezoelectric member, the individual electrode, and the second common electrode
Data Source
AI summary
There is provided a print apparatus including: a piezoelectric member; an individual electrode formed in the piezoelectric member; a first common electrode formed in the piezoelectric member so that the first common electrode is opposed to the individual electrode; a second common electrode formed in the piezoelectric member so that the second common electrode is opposed to the individual electrode, a voltage to be applied to the second common electrode being different from a voltage to be applied to the first common electrode; and a detection circuit configured to detect a capacitance of a first capacitor configured by the piezoelectric member, the individual electrode, and the first common electrode and a second capacitor configured by the piezoelectric member, the individual electrode, and the second common electrode. The detection circuit includes an oscillation circuit configured to be connected to the individual electrode.