Piezoelectric Inkjet Actuator Polarization Control
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Solution Overview
Problem
Conventional inkjet printers experience changes in ink discharge characteristics over time due to prolonged fixed and eased stress cycles on the piezoelectric film, leading to decreased ink discharge efficiency and rate.
Innovation Solution
The inkjet printer incorporates a controller that applies a peripheral signal between additional electrodes on the piezoelectric actuator to maintain the polarization state of the piezoelectric film, preventing characteristic changes by applying voltage to the peripheral portion, thus maintaining consistent ink discharge performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the piezoelectric actuator is continuously deformed and relaxed during non-discharge periods, then ink discharge can be maintained, but the polarization state of the piezoelectric film changes leading to degraded ink discharge characteristics
Solution Approach 1:
The patent applies a preliminary action by maintaining a predetermined voltage on the piezoelectric film during non-discharge periods to prevent polarization state changes. This preliminary voltage application counteracts the harmful effect of stress cycle accumulation before it can degrade ink discharge characteristics, thereby resolving the contradiction between maintaining productivity and ensuring long-term reliability.
2Reliability
If voltage is applied to the piezoelectric film during non-discharge periods to maintain polarization state, then ink discharge characteristics remain stable, but energy is continuously consumed
Solution Approach 1:
The patent implements periodic action by applying voltage to the piezoelectric film only during specific non-discharge periods rather than continuously. The controller strategically timing voltage application to coincide with non-discharge intervals, thereby maintaining polarization state and ink discharge characteristics while minimizing energy consumption compared to continuous voltage application.
3Duration of action of moving object
If the piezoelectric film is subjected to repeated stress cycles, then ink discharge operation continues, but the polarization state changes causing decreased ink discharge rate
Solution Approach 1:
The patent applies preliminary anti-action by counteracting the harmful stress cycle effects before they can significantly degrade ink discharge rate. By maintaining a predetermined voltage during non-discharge periods, the system prevents polarization state changes that would otherwise occur due to repeated mechanical stress, thereby extending operation duration while maintaining high ink discharge rate.
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 approach ensures that ink discharge characteristics remain stable over long-term use, preventing the degradation of ink discharge efficiency and rate by mitigating stress-induced changes in the piezoelectric film.
Implementation Method 1
the piezoelectric film deforms due to the piezoelectric effect. As a result, the piezoelectric actuator deforms. Because the piezoelectric actuator forms a portion of the wall defining the pressure chamber, the volume of the pressure chamber changes due to the deformation of the piezoelectric actuator.
Implementation Method 2
The generated pressure decrease develops a pressure wave within the pressure chamber. The developed pressure wave will propagate from the pressure chamber to the nozzle through an ink passage communicating the pressure chamber and the nozzle, and the pressure wave is reflected at the nozzle toward the pressure chamber.
Data Source
AI summary
The lnkjet printer has a pressure chamber, a plezoelectric actuator, and a controller. The plezoelectrlc actuator has a piezoelectric film, a first electrode, a second electrode, and a third electrode. The first electrode, positioned in the region facing the pressure chamber, and the third electrode, positioned adjacent to the first electrode, are attached on one surface of the piezoeiectric film. The second electrode is attached on an opposite surface of the piezoelectric film and overlaps the first and third electrodes. To discharge ink, the controller applies an ink discharge signal between the first and second electrodes comprising an advanced voltage change from a predetermined voltage to the lower voltage and a subsequent voltage change from the lower voltage to the predetermined voltage. The controller also applies a peripheral signal between the second and thIrd electrodes to prevent changes in characteristics of the piezoelectrlc actuator that may affect ink discharge.