Liquid Jet Head Droplet Control via Segmented Pulse Signals
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Solution Overview
Problem
Existing liquid jet recording devices face challenges in achieving high-definition image quality due to limitations in controlling the size of droplets ejected by the liquid jet head, particularly in reducing the minimum drop volume without altering the head structure.
Innovation Solution
The implementation of a method that applies a first pulse signal with a pulse width equal to or shorter than the on-pulse peak, followed by a second pulse signal with a predetermined time interval, to control the capacity of the pressure chamber and reduce the size of the droplet in 1-drop ejection, allowing for the reduction of the minimum drop volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single pulse signal with pulse width equal to the on-pulse peak is applied to eject 1 drop, then the ejection speed is maximized, but the minimum drop volume cannot be reduced further
Solution Approach 1:
The single pulse signal is segmented into multiple pulse signals (first pulse signal followed by second pulse signal). The first pulse signal ejects the droplet, and the second pulse signal subsequently reduces the drop volume by retracting part of the ejected liquid back into the pressure chamber. This segmentation allows independent control of ejection speed and drop volume.
Solution Approach 2:
The invention uses periodic pulse signals with specific timing intervals. The first pulse signal is applied during the on-pulse peak for maximum ejection speed, and the second pulse signal is applied after a predetermined time interval to reduce the drop volume. This periodic action enables precise control over both speed and quantity parameters.
2Quantity of substance
If the pulse width is reduced to minimize drop volume, then the minimum drop volume is reduced, but the ejection speed decreases
Solution Approach 1:
The first pulse signal is applied in advance during the on-pulse peak to maximize ejection speed and initiate droplet formation. Subsequently, the second pulse signal is applied to perform the volume reduction action. This preliminary action ensures that ejection speed is maximized before the volume control action occurs.
Solution Approach 2:
By using periodic pulse signals with optimized widths and intervals, the system first achieves maximum ejection speed with the first pulse, then reduces drop volume with the second pulse. The periodic nature allows each pulse to be optimized for its specific function without compromising the other parameter.
3Quantity of substance
If multiple pulse signals are applied continuously to grow droplet size, then grayscale or high-concentration pixels are formed, but the minimum drop volume control precision is reduced
Solution Approach 1:
The pulse signal sequence is segmented into a first pulse for ejection and a second pulse for volume adjustment. This segmentation provides a standardized starting point (1 drop) with precise minimum volume control, from which grayscale pixels can be formed by adding more pulses. The segmentation ensures that each base droplet has consistent, precisely controlled volume.
Solution Approach 2:
The second pulse signal provides feedback control by retracting excess liquid back into the pressure chamber based on the droplet formation process. This feedback mechanism ensures that the minimum drop volume is precisely controlled before any additional pulses are applied for grayscale formation, maintaining precision in the base droplet size.
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 effectively reduces the size of the droplet in 1-drop ejection by up to 51% compared to conventional methods, enhancing the image quality without modifying the liquid jet head structure.
Implementation Method 1
application of a pulse signal to a piezoelectric actuator, the capacity of a pressure chamber varies, and thus, a liquid filling the pressure chamber is jetted from a nozzle
Data Source
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AI summary
Reduction of the size of the droplet in 1-drop ejection is easily performed. A liquid jet head according to an example of the disclosure includes a nozzle adapted to jet a liquid, a piezoelectric actuator having a pressure chamber communicated with the nozzle and filled with the liquid, and adapted to vary a capacity of the pressure chamber, and a control section adapted to apply a pulse signal to the piezoelectric actuator to thereby expand and contract the capacity of the pressure chamber so as to jet the liquid filling the pressure chamber. The control section applies the pulse signal adapted to expand the capacity in the pressure chamber when jetting 1 drop of the liquid so as to include a first pulse signal having a pulse width one of equal to or shorter than an on-pulse peak, and a second pulse signal disposed with a predetermined time interval from the first pulse signal.