Liquid Ejection Head Pulse Control for Droplet Adjustment
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Solution Overview
Problem
Existing liquid ejection heads require structural changes to nozzle diameter or actuator strength to adjust droplet amount, which complicates print quality adjustments and waveform adjustments.
Innovation Solution
A liquid ejection head with a pressure chamber and actuator driven by a drive circuit that applies specific pulses - auxiliary, ejection, cancel, and damping pulses - to control pressure and vibration, allowing for adjustable droplet ejection without altering the head structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the diameter of the nozzle or the strength of the actuator is changed to adjust the ejected droplet amount, then the droplet ejection amount can be adjusted, but the head structure becomes more complex and print quality adjustment takes more time
Solution Approach 1:
The patent changes the operational parameters of the actuator (drive waveform, pulse width, frequency) rather than modifying the physical structure of the nozzle or actuator. By adjusting the drive signal parameters, the ejected droplet amount can be controlled without changing the head structure, thus resolving the contradiction between droplet amount adjustment and structural complexity.
Solution Approach 2:
The patent makes the droplet ejection amount dynamically adjustable through real-time modification of the drive waveform parameters. The actuator can be controlled to produce different droplet amounts by changing the drive signal characteristics (such as pulse width modulation), allowing flexible adjustment without structural changes to the head.
2Quantity of substance
If the shape of the nozzle is changed to adjust the ejected droplet amount, then the droplet ejection amount can be adjusted, but the print quality changes and it takes time to adjust the drive waveform
Solution Approach 1:
Instead of changing the nozzle shape, the patent adjusts the drive waveform parameters (pulse width, frequency, amplitude) to control droplet amount. This approach allows rapid parameter adjustment without the time-consuming process of redesigning and manufacturing new nozzle geometries, significantly reducing adjustment time.
Solution Approach 2:
The system enables dynamic adjustment of droplet ejection characteristics through real-time modification of drive signal parameters. This allows quick adaptation to different printing requirements without physical reconfiguration, eliminating the time loss associated with structural changes.
3Quantity of substance
If the drive waveform is adjusted to change the ejected droplet amount, then the droplet ejection amount can be adjusted, but the print quality becomes unstable
Solution Approach 1:
The patent employs periodic drive waveforms with specific pulse patterns to control droplet ejection. By using well-defined periodic signals with controlled pulse widths and frequencies, the system achieves stable and repeatable droplet ejection amounts, maintaining print quality consistency while enabling adjustment of droplet volume.
Solution Approach 2:
The patent implements feedback mechanisms to monitor and adjust the drive waveform parameters, ensuring stable droplet ejection. By incorporating feedback control, the system can compensate for variations and maintain consistent print quality while adjusting droplet amounts through controlled waveform modifications.
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
Enables flexible adjustment of droplet ejection volume and speed without changing the head structure, improving print quality and efficiency by stabilizing gradation and ejection performance.
Implementation Method 1
The actuator changes pressure of the liquid in response to an applied drive signal
Implementation Method 2
The auxiliary pulse drives the actuator so that the pressure is increased
Implementation Method 3
The ejection pulse drives the actuator so that the pressure is reduced to eject the liquid from a nozzle
Implementation Method 4
The cancel pulse drives the actuator so that the pressure is increased to suppress residual vibration of the liquid
Implementation Method 5
The damping pulse drives the actuator so that the pressure is reduced to suppress the residual vibration
Data Source
Figure 1
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AI summary
According to one embodiment, a drive signal includes an auxiliary pulse (B), an ejection pulse (Da), a cancel pulse (Pa), and a damping pulse (DMP), in this order. The auxiliary pulse drives an actuator so that the pressure is increased. The ejection pulse drives the actuator so that the pressure is reduced to eject the liquid. The cancel pulse drives the actuator so that the pressure is increased to suppress residual vibration of the liquid. The damping pulse drives the actuator so that the pressure is reduced to suppress the residual vibration. A pulse width of the auxiliary pulse is AL or less . A pulse width of the cancel pulse is 2 AL. A length from an end of the application of the cancel pulse to a start of the application of the damping pulse is 0.2 AL to 0.4 AL. A pulse width of the damping pulse is 0.2 AL to 0.4 AL.