Piezoelectric Element Voltage Monitoring for Pump Abnormality Detection
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Solution Overview
Problem
Existing ink-jet printers require additional electrodes and circuits to detect pump abnormalities, increasing apparatus size and production costs.
Innovation Solution
A liquid ejecting apparatus with a head, cleaning part, and controller that uses a piezoelectric element to detect abnormalities by monitoring voltage changes during liquid discharge processes, simplifying the configuration and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrodes and discriminating circuits are added to detect pump abnormalities, then the reliability of pump detection is improved, but the device complexity and production cost increase
Solution Approach 1:
The piezoelectric element is designed to serve multiple functions: it acts as both the actuator for ejecting liquid droplets and the sensor for detecting pump abnormalities. When a voltage is applied, it functions as an actuator to change the internal volume of the pressure chamber and eject liquid. When monitoring voltage changes during pump operation, it functions as a sensor to detect abnormalities. This multi-functionality eliminates the need for separate detection electrodes and circuits, thereby reducing device complexity while maintaining detection reliability.
Solution Approach 2:
The piezoelectric element monitors its own voltage changes to detect pump abnormalities. By observing the voltage variation across itself during pump operation, the system enables self-diagnosis without requiring external sensing components. This self-service approach allows the same component to both perform its primary function and provide diagnostic information, simplifying the overall system configuration.
2Reliability
If electrodes and discriminating circuits are added to detect pump abnormalities, then the reliability of pump detection is improved, but the production cost increases
Solution Approach 1:
The piezoelectric element is designed to serve multiple functions: it acts as both the actuator for ejecting liquid droplets and the sensor for detecting pump abnormalities. When a voltage is applied, it functions as an actuator to change the internal volume of the pressure chamber and eject liquid. When monitoring voltage changes during pump operation, it functions as a sensor to detect abnormalities. This multi-functionality eliminates the need for separate detection electrodes and circuits, thereby reducing device complexity while maintaining detection reliability.
Solution Approach 2:
The detection function is merged with the existing piezoelectric actuator rather than being implemented as a separate system. The same piezoelectric element that is already present in the liquid ejecting head for droplet ejection is utilized for abnormality detection by monitoring its voltage characteristics. This merging of functions reduces the total component count and eliminates the need for additional electrodes and discriminating circuits, thereby reducing production costs.
3Device complexity
If a simple configuration is used without additional electrodes, then the device complexity is reduced, but the ability to detect pump abnormalities is worsened
Solution Approach 1:
The piezoelectric element monitors its own voltage changes to detect pump abnormalities. By observing the voltage variation across itself during pump operation, the system enables self-diagnosis without requiring external sensing components. This self-service approach allows the same component to both perform its primary function and provide diagnostic information, simplifying the overall system configuration.
Solution Approach 2:
The system implements feedback by continuously monitoring the voltage across the piezoelectric element during pump operation. The controller compares the monitored voltage against expected ranges to detect abnormalities. This feedback mechanism enables real-time detection of pump issues using the existing piezoelectric element, maintaining detection capability while avoiding additional hardware complexity.
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 apparatus effectively detects pump abnormalities through a simple configuration, reducing size and production costs while maintaining efficient liquid discharge operations.
Implementation Method 1
a piezoelectric element which forms a part of a wall of the head flow passage... obtainment of a voltage of the piezoelectric element during a period in which the liquid inside the head flow passage is being discharged
Implementation Method 2
a negative pressure pump configured to generate a negative pressure... execute discharge of a liquid inside the head flow passage from the nozzle by driving the negative pressure pump
Implementation Method 3
a positive pressure pump configured to apply a positive pressure to a liquid inside the head flow passage... execute discharge of the liquid inside the head flow passage from the nozzle to the liquid receiving part by driving the positive pressure pump
Data Source
AI summary
A liquid ejecting apparatus includes a head, a cleaning part, and a controller. The head has a head flow passage, and a piezoelectric element which forms a part of a wall of the head flow passage. The cleaning part has a nozzle cap, a negative pressure pump, and a liquid discharge connecting flow passage. The controller is configured to execute discharge of a liquid inside the head flow passage from a nozzle by driving the negative pressure pump in a state that the nozzle is covered with the nozzle cap, obtainment of a voltage of the piezoelectric element during a period in which the liquid inside the head flow passage is being discharged from the nozzles, and output of an abnormality signal which indicates that at least a part of the cleaning part is abnormal in a case where the obtained voltage does not satisfy a liquid discharge-voltage condition.