Liquid Ejection Pulse Control for Stable Multi-Droplet Merging
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Solution Overview
Problem
Existing liquid ejecting apparatuses face challenges in combining multiple droplets effectively due to difficulties in adjusting droplet speeds and volumes, leading to inconsistent or incomplete droplet merging on the medium.
Innovation Solution
A drive signal generator produces a sequence of ejection pulses with interpulse components maintained at a reference potential, including filling and ejection components, and vibration suppression components to manage pressure changes in the pressure chamber, ensuring synchronized droplet ejection and residual vibration damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of droplets to be ejected from a nozzle is increased, then the amount of combined droplet can be increased, but it becomes difficult to combine all droplets at a desired position and requires significantly reducing the amount of preceding droplets to lower flying speed
Solution Approach 1:
The patent applies parameter changes by varying the drive voltage for each droplet in a controlled sequence. Specifically, the drive voltage is set to a first voltage level for initial droplets and then transitions to a second voltage level for subsequent droplets. This voltage parameter change enables precise control over droplet ejection speed and timing, allowing multiple droplets to be ejected and combined at desired positions without requiring reduction of preceding droplet amounts.
2Reliability
If the drive voltage for succeeding droplets is increased to combine droplets, then droplet combination is achieved, but the flying speed control becomes difficult and droplet amount consistency deteriorates
Solution Approach 1:
The patent segments the ejection process into distinct phases with different voltage levels. The drive signal is divided into a first drive voltage phase for initial droplet ejection and a second drive voltage phase for subsequent droplet ejection. This segmentation allows each phase to be optimized independently - the first phase ensures proper droplet formation while the second phase ensures droplet combination, maintaining overall reliability without compromising droplet amount consistency.
3Speed
If the flying speed of preceding droplets is reduced to enable combination, then droplet combination is possible, but the amount of preceding droplets must be significantly reduced
Solution Approach 1:
The patent implements dynamic control of droplet ejection by varying drive voltage levels over time. The system transitions from a first drive voltage for initial droplets to a second drive voltage for subsequent droplets, creating dynamic speed adjustment. This allows preceding droplets to maintain optimal amounts while subsequent droplets are ejected at adjusted speeds to achieve combination, eliminating the need to reduce preceding droplet amounts.
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 enables precise control over droplet formation, allowing for stable and efficient combination of multiple droplets on the medium, enhancing the size and consistency of the combined droplet.
Implementation Method 1
a drive element, such as a piezoelectric element, that changes pressure applied to liquid in the pressure chamber according to a drive signal
Implementation Method 2
filling components that cause the pressure in the pressure chamber to be negative, and ejection components that cause the pressure in the pressure chamber to be positive in such a way that droplets are ejected from the nozzle
Implementation Method 3
first vibration suppression components that succeed the ejection components of the second ejection pulses and dampen residual vibration in the pressure chamber by changing from the second potential to the reference potential
Data Source
AI summary
A liquid ejecting apparatus is configured to eject liquid in response to a drive signal. The drive signal includes a first ejection pulse, a plurality of second ejection pulses, and a third ejection pulse. An ejection component of the first ejection pulse changes from a first potential to a reference potential and is temporally continuous with an interpulse component. Ejection components of the second and third ejection pulses change from the first potential to a second potential. The second ejection pulses include first vibration suppression components that change from the second potential to the reference potential after the ejection components. The third ejection pulse includes a second vibration suppression component that changes from the second potential to a third potential. The reference potential is a potential between the first potential and the second potential and between the second potential and the third potential.