Inkjet Transducer Frequency Control for Air Bubble Elimination
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Solution Overview
Problem
Existing inkjet printing methods for removing air bubbles from ink ducts either result in significant ink loss or require lengthy interruptions in the printing process, as they either flush the duct with new ink or allow air bubbles to dissolve over time.
Innovation Solution
Actuating the transducer at a frequency lower than the equilibrium frequency of the air bubble, with sufficient amplitude to eject ink drops, allows the air bubble to quickly shrink to a size that no longer affects print quality, and subsequent frequency adjustments can further reduce the bubble size in stages, ensuring minimal ink loss and rapid resumption of printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the duct is flushed with new ink to eliminate air bubbles, then the air bubbles are removed from the duct, but significant ink loss occurs
Solution Approach 1:
The patent changes the actuation parameters of the transducer, specifically using a first actuation frequency that is lower than the equilibrium frequency of the air bubble. This parameter change enables air bubble elimination through frequency-based control rather than ink flushing, significantly reducing ink loss while maintaining reliable air bubble removal
2Reliability
If the printing process is interrupted to allow air bubbles to dissolve in the ink, then the air bubbles are eliminated from the duct, but the printing process requires long interruption periods
Solution Approach 1:
The patent applies periodic actuation of the transducer at a specific frequency (first actuation frequency lower than equilibrium frequency) to actively eliminate air bubbles. This periodic mechanical action replaces passive dissolution waiting time with active frequency-based bubble removal, dramatically reducing printing process interruptions
Solution Approach 2:
The system detects air bubbles in advance and applies the first actuation frequency treatment before the air bubbles can significantly affect printing quality. This preliminary active elimination prevents the need for long interruption periods that would be required for natural dissolution
3Speed
If the transducer is actuated at a frequency lower than the equilibrium frequency of the air bubble, then the air bubble size decreases quickly, but ink drops are ejected from the duct
Solution Approach 1:
The patent uses parameter changes in a two-stage process: first actuation frequency (lower than equilibrium) for rapid bubble shrinkage, then second actuation frequency (even lower) for complete elimination. This staged parameter adjustment achieves fast bubble removal while minimizing total ink loss compared to flushing
Solution Approach 2:
The system dynamically adjusts the actuation frequency in two stages: initially using a first frequency below equilibrium to rapidly shrink the bubble, then transitioning to a second lower frequency to eliminate it completely. This dynamic frequency adjustment optimizes both shrinkage speed and ink loss minimization
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 method enables the rapid elimination of air bubbles with minimal ink loss, allowing for quick resumption of the printing process without adverse effects on print quality, as the air bubbles are reduced to sizes that do not interfere with ink drop formation and often disappear quickly with the ink drops.
Implementation Method 1
the presence of an air bubble in the ink duct is determined by the application of a piezo-electric transducer used as a sensor
Implementation Method 2
said duct being operationally connected to an electro-mechanical transducer
Data Source
AI summary
A printing method for use with an inkjet printer containing a substantially closed ink duct including a nozzle, said duct being operationally connected to an electro-mechanical transducer, the presence of an air bubble in the duct is determined and the air bubble is subsequently eliminated, wherein the elimination of the air bubble takes place by actuating the transducer at a frequency which is lower than the frequency that corresponds to the size of the air bubble in equilibrium, and the amplitude is sufficient to arrange for the ink drops to be ejected from the nozzle. The invention also relates to an inkjet printer which has been modified to use the present method.