Piezoelectric Element Drive Voltage Control for Inkjet Printers
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Solution Overview
Problem
The existing liquid ejection apparatus, such as inkjet printers, face issues with piezoelectric element deterioration due to continuous drive voltage application, leading to differences in deterioration among elements, which can cause breakage of the voltage supply circuit and inefficient ink ejection.
Innovation Solution
A control method and apparatus that calculates the accumulated time of each piezoelectric element unit, identifies the maximum and minimum accumulated times, and adjusts the drive voltage to reduce differences, thereby reducing deterioration and preventing circuit breakage by applying a lower voltage to non-driven units when the time difference is below a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If drive voltage is continuously applied to piezoelectric elements during printing operation, then the electrical connection between electrodes remains connected enabling continuous operation, but the piezoelectric elements deteriorate due to prolonged polarization
Solution Approach 1:
The patent applies periodic disconnection and reconnection of electrical connections between electrodes during printing operations. Specifically, the control device periodically disconnects and reconnects the electrical connection between first and second electrodes sandwiching piezoelectric elements that are not driven, thereby reducing deterioration while maintaining continuous printing capability. This periodic action prevents prolonged polarization damage while ensuring operational continuity.
2Duration of action of stationary object
If electrical connection between electrodes is disconnected during printing operation to reduce piezoelectric element deterioration, then the operating life of ink ejection head is extended, but differences in deterioration among piezoelectric elements increase
Solution Approach 1:
The patent implements local quality control by individually managing electrical connections for each piezoelectric element or group of elements. The control device selectively disconnects and reconnects electrical connections based on which specific piezoelectric elements are driven or not driven, rather than applying a uniform disconnection strategy to all elements. This localized approach ensures that non-driven elements receive protective disconnection while driven elements maintain their operational connections, thereby reducing overall deterioration while maintaining uniformity across the array.
Solution Approach 2:
The system employs feedback control where the control device monitors which piezoelectric elements are driven during printing operations and uses this information to determine which electrical connections to disconnect or maintain. This feedback mechanism ensures that the disconnection strategy adapts to the actual operational state, preventing excessive deterioration differences among elements by dynamically adjusting connections based on real-time drive status.
3Stability of the object's composition
If drive voltage is adjusted for each piezoelectric element based on deterioration degree, then the uniformity of element performance is maintained, but the voltage reduction range of linear regulators increases causing overheating
Solution Approach 1:
The patent uses periodic disconnection and reconnection of electrical connections as an alternative to continuous voltage adjustment. By periodically disconnecting electrical connections for non-driven piezoelectric elements, the system reduces their deterioration without requiring continuous voltage reduction. This periodic approach maintains performance uniformity while avoiding the sustained voltage reduction that would cause linear regulators to overheat, as the disconnection provides protection without the thermal burden of continuous voltage regulation.
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 extends the operating life of piezoelectric elements, reduces differences in deterioration, and minimizes the risk of voltage supply circuit damage by dynamically adjusting the drive voltage based on the accumulated time and temperature of each element.
Implementation Method 1
each of the piezoelectric element units of the ink ejection head includes a polarized piezoelectric element. A drive voltage is applied to the piezoelectric elements to drive the piezoelectric elements. Thus, ink is ejected from the ink ejection head onto a recording medium.
Data Source
AI summary
A liquid ejection apparatus comprises a plurality of piezoelectric element units, which can be driven to eject liquid by changing a drive voltage, and a control device. The control device may calculate an accumulated time for each of the piezoelectric element units. The accumulated times may be a time that a respective piezoelectric element unit is in a driven state. The control device may also identify a first piezoelectric element unit having a maximum accumulated time and a second piezoelectric element unit having a minimum accumulated time from among the piezoelectric element units. The control device may reduce the drive voltage applied to one or more of the piezoelectric element units that are not in the driven state to a lower voltage, when the control device determines that the difference between the maximum accumulated time and the minimum accumulated time is less than a predetermined time.