Piezoelectric Ink Jet Head Micro-Vibration Control
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Solution Overview
Problem
The piezoelectric actuator in liquid discharge devices experiences residual vibration, which affects the stability of the ink meniscus and leads to variations in ink drop size and shape, resulting in degraded image quality, including misaligned and deformed dots and excessive mist generation.
Innovation Solution
A micro vibration control mechanism is introduced to forcibly align residual vibrations with micro vibrations during waiting periods, using controlled ON/OFF drive voltage techniques to maintain a stable ink meniscus and consistent ink drop formation, thereby minimizing residual vibration amplitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the piezoelectric actuator is driven with standard drive voltage waveforms, then ink drop discharge is achieved, but residual vibration occurs that degrades image quality
Solution Approach 1:
The patent applies periodic micro-vibrations to the piezoelectric actuator during waiting time periods between ink drop discharges. The control unit repeatedly switches the drive voltage between high and low states at a frequency matching the actuator's natural vibration frequency, creating controlled micro-vibrations that counteract and eliminate residual vibrations from previous discharge cycles, thereby stabilizing the ink meniscus and improving image quality
Solution Approach 2:
The control unit incorporates feedback control by detecting the vibration state of the piezoelectric actuator and adjusting the drive voltage waveform accordingly. During waiting time periods, the control unit monitors residual vibrations and applies corrective micro-vibrations through feedback-controlled voltage switching, ensuring complete vibration elimination before the next ink drop discharge, thus maintaining consistent image quality
2Stability of the object's composition
If residual vibration amplitude is reduced, then ink meniscus stability improves, but requiring additional micro-vibration control mechanisms
Solution Approach 1:
The control unit performs multiple functions: it controls the main drive voltage waveforms for ink drop discharge, generates micro-vibration control signals during waiting time periods, and processes feedback signals from the piezoelectric actuator. By integrating these functions into a single control unit, the patent avoids adding separate micro-vibration control mechanisms, thereby maintaining ink meniscus stability while minimizing device complexity
Solution Approach 2:
The control unit performs preliminary micro-vibration control actions during waiting time periods before the next ink drop discharge is required. By eliminating residual vibrations in advance during these idle periods, the system ensures the ink meniscus is fully stabilized before the next discharge cycle begins, preventing image quality degradation without requiring complex real-time control during actual discharge operations
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 consistent ink drop size and shape, preventing image quality degradation by maintaining the stability of the ink meniscus and reducing mist generation, thus enhancing the overall image quality.
Implementation Method 1
The piezoelectric ceramic layer 6 is formed of a piezoelectric material such as PZT, and is given piezoelectric deformation characteristics in a so-called transverse vibration mode by being previously polarized in the thickness direction of the layer. When a drive voltage in the same direction as the direction of the polarization is applied from the drive circuit 13 to an area between the discrete electrode 10 that define any one of the piezoelectric deformation regions 8 and the common electrode 11, an active region 15, which corresponds to the piezoelectric deformation region 8 and is sandwiched between both the electrodes 10 and 11, contracts in the planar direction of the layer
Implementation Method 2
When the piezoelectric deformation region 8 is vibrated by combining a state where the piezoelectric deformation region 8 is deflected and deformed and a state where the application of the drive voltage is stopped to release the deflection and deformation, the ink filled in the pressure chamber 2 is pressurized by the vibration and is discharged as an ink drop through the nozzle 3
Data Source
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AI summary
It is possible to minimize the amplitude of residual vibration of a piezoelectric actuator so as to maintain the image quality of a formed image at a preferable level in case of an ink jet head, for example. A liquid discharge device includes a control unit (14) for ON/OFF control of a drive voltage applied to the piezoelectric actuator. The control unit (14) has a micro vibration control section (23) for drive-controlling a drive circuit so as to micro-vibrate the piezoelectric actuator in a waiting state not discharging a liquid drop from a nozzle, in a range that no liquid drop is discharged in the nozzle. The piezoelectric ink jet head includes the liquid discharge device. The drive method is for micro-vibrating the piezoelectric actuator in the waiting state not discharging a liquid drop from the nozzle, in a range that no liquid drop is discharged from the nozzle.