Piezoelectric Printhead Multipulse Drive Waveform for Droplet Control
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Solution Overview
Problem
Piezoelectric ink jet printers face challenges in achieving precise control over ink droplet size and stability, leading to satellite droplet formation and misfiring due to resonance frequency-based actuation, which results in reduced image acuity and increased air ingestion.
Innovation Solution
A method involving a multipulse burst with specifically timed energy imparting pulses, where the intervals between pulses are adjusted based on the jet's resonance frequency and meniscus-jet mass frequency to prevent satellite droplet formation, using a controller to actuate the actuator with a first energy pulse, followed by a second pulse after a first interval, and a break-off pulse after a second, longer interval, optimizing the timing to match the inverse of the meniscus-jet mass frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the actuator is actuated at resonant frequency or higher frequency to eject ink droplets, then productivity is improved, but satellite droplet formation occurs reducing manufacturing precision
Solution Approach 1:
The patent applies periodic action by using multiple drive pulses within a burst waveform, where each pulse is separated by specific time intervals. The first pulse ejects a primary droplet, the second pulse ejects a secondary droplet, and subsequent pulses combine their effects. By controlling the timing and number of pulses in the burst, the system achieves precise droplet size control while maintaining high ejection frequency, thus resolving the contradiction between productivity and manufacturing precision.
2Adaptability or versatility
If sequential actuation of piezoelectric material is used to create varying droplet sizes, then adaptability is improved, but satellite droplets are formed reducing reliability
Solution Approach 1:
The patent employs parameter changes by varying the number of drive pulses in a burst, the amplitude of each pulse, and the time intervals between pulses. By adjusting these parameters, the system can control droplet size, velocity, and formation characteristics. This allows adaptable droplet size variation while maintaining reliable printing by optimizing pulse parameters to prevent satellite droplet formation and ensure consistent droplet ejection.
3Productivity
If high frequency actuation is used to combine successive volumes into single droplets, then productivity is improved, but air ingestion increases reducing stability
Solution Approach 1:
The patent applies preliminary action by using the first drive pulse in a burst to eject a droplet that clears the nozzle orifice and prevents air ingestion. Subsequent pulses in the burst then add volume to the droplet without requiring the nozzle to be re-filled, thereby maintaining stable nozzle functionality while achieving high productivity through combined pulse action.
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 allows for efficient ejection of ink droplets of varying sizes with reduced satellite droplets, improving image acuity and preventing air ingestion, resulting in more stable and accurate printing by minimizing unwanted droplet formation and maintaining nozzle functionality.
Implementation Method 1
At least one wall of the ink chamber is coupled to a piezoelectric material. When actuated, the piezoelectric material deforms. This deformation results in a deformation of the wall, which in turn launches a pressure wave that ultimately pushes ink out of the orifice
Implementation Method 2
An actuator is actuated with a first energy imparting pulse to push fluid away from the actuator and toward a nozzle
Implementation Method 3
the second lapse is longer than the first lapse and is an inverse of the meniscus jet mass frequency
Data Source
AI summary
A method for causing fluid to be ejected from a fluid chamber of a jet in a printhead. An actuator is actuated with a first energy imparting pulse to push fluid away from the actuator and toward a nozzle. Following a lapse of a first interval, the actuator is actuated with second energy imparting pulse to push fluid away from the actuator and toward the nozzle. Following a lapse of a second interval as measured from the second energy imparting pulse, the actuator is actuated with a break-off pulse to cause fluid extending out of an orifice of the nozzle to break off from fluid within the nozzle, wherein the second lapse is longer than the first lapse and is an inverse of the meniscus-jet mass frequency.