Piezoelectric Drive Circuit Voltage Matching for Inkjet Sleep State
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Solution Overview
Problem
In inkjet printers, unintended displacement of piezoelectric elements during the sleep state due to leakage current leads to excessive bending of vibration plates, potentially causing cracks and reducing ink ejection accuracy, as the piezoelectric elements are not fully isolated when the switch circuit is turned off, resulting in unintended stress and potential ink leakage.
Innovation Solution
A liquid ejecting apparatus with a drive circuit that controls the voltage of the first voltage signal to approximate the second voltage signal when the switch element is turned off, reducing the potential difference between the electrodes and minimizing unintended displacement of the piezoelectric element, thereby reducing stress on the vibration plate and maintaining ink ejection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the switch circuit is turned off to reduce power consumption in sleep state, then power consumption is reduced, but leakage current flows through resistance components causing unintended potential difference and piezoelectric element displacement
Solution Approach 1:
The invention applies preliminary anti-action by controlling the first voltage signal to approximate the second voltage signal before turning off the switch circuit. This preemptive voltage matching prevents the buildup of unintended potential differences that would otherwise occur due to leakage current, thereby avoiding unwanted piezoelectric element displacement while maintaining the power-saving sleep state.
Solution Approach 2:
The invention implements equipotentiality by ensuring that the first voltage signal and second voltage signal are controlled to have approximately equal voltage values. This creates an equipotential condition between the first electrode and second electrode, eliminating potential difference and preventing leakage current from causing unintended piezoelectric element displacement during the sleep state.
2Ease of operation
If the piezoelectric element is displaced in sleep state due to unintended potential difference, then the vibration plate experiences larger bending than expected, but this causes stress concentration and potential cracks in the vibration plate
Solution Approach 1:
The invention applies preliminary anti-action by controlling the voltage signals to approximate each other before the switch circuit is turned off. This preemptive measure prevents the development of unintended potential differences that would cause piezoelectric element displacement and subsequent vibration plate bending, thereby avoiding stress concentration and potential cracks.
Solution Approach 2:
The invention implements beforehand cushioning by proactively controlling the voltage signals to minimize potential difference before the harmful effect (leakage current-induced displacement) can occur. This protective measure cushions the vibration plate against unintended stress by preventing the chain reaction of displacement and bending that would lead to structural damage.
3Use of energy by stationary object
If the vibration plate experiences larger bending in sleep state, then stress is continuously applied to the vibration plate, but this reduces ink ejection accuracy when transitioning to print state
Solution Approach 1:
The invention applies preliminary anti-action by controlling the voltage signals to approximate each other before entering sleep state. This prevents unintended piezoelectric element displacement and vibration plate bending during the energy-saving period, ensuring that the system returns to the print state with minimal stress and optimal ink ejection accuracy.
Solution Approach 2:
The invention implements feedback by continuously monitoring and controlling the voltage signals to maintain their approximation during sleep state. This feedback mechanism ensures that the piezoelectric element and vibration plate remain in a stable, low-stress condition, preserving ink ejection accuracy when the system transitions back to print state.
4Reliability
If ink leaks from cracks in the vibration plate, then the cavity volume changes affect ejection amount, but this causes fluctuation in ink ejection accuracy
Solution Approach 1:
The invention implements beforehand cushioning by proactively controlling the voltage signals to prevent piezoelectric element displacement and vibration plate bending before cracks can form. This protective measure maintains cavity integrity and prevents ink leakage, ensuring consistent ejection accuracy by eliminating the root cause of cavity volume variations.
Solution Approach 2:
The invention applies preliminary anti-action by preventing the chain reaction that leads to crack formation. By controlling voltage signals to approximate each other, the system prevents unintended displacement, reduces vibration plate stress, and eliminates the conditions that would cause cracks and subsequent ink leakage, thereby maintaining reliable cavity sealing and ejection accuracy.
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 effectively reduces the stress on the vibration plate and maintains ink ejection accuracy by minimizing unintended displacement of the piezoelectric element, preventing cracks and ensuring consistent ink ejection, even during extended sleep states.
Implementation Method 1
a piezoelectric element that includes a first electrode to which the first voltage signal is supplied and a second electrode to which a second voltage signal is supplied and is displaced by a potential difference between the first electrode and the second electrode
Data Source
AI summary
A liquid ejecting apparatus includes a drive circuit in which a first voltage signal is output from an output terminal, a piezoelectric element that includes a first electrode to which the first voltage signal is supplied and a second electrode to which a second voltage signal is supplied and is displaced by a potential difference between the first electrode and the second electrode, a cavity which is filled with a liquid, a vibration plate that is provided between the cavity and the piezoelectric element, and a switch element that is electrically connected to the output terminal and the first electrode. The liquid ejecting apparatus has a mode in which the switch element is controlled to be turned off, and a voltage value of the first voltage signal is controlled to approximate a voltage value of the second voltage signal.