Inkjet Printhead Waveform Timing to Reduce Nozzle Cross-Talk
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Solution Overview
Problem
Continuous inkjet printing technologies face challenges in preventing the formation of print artifacts under certain conditions, which affect print quality and efficiency.
Innovation Solution
The method involves segmenting the nozzle array into interleaved groups with phase-shifted and energy-modulated drop-formation waveforms, using a timing delay device to synchronize drop break-off times and electrostatic deflection, allowing for effective separation of printing and non-printing drops using a common charging electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common charging electrode is used for both nozzle groups, then device complexity is reduced, but cross-talk artifacts occur due to unsynchronized drop break-off times
Solution Approach 1:
The nozzle array is segmented into two interleaved groups (first group and second group) that are controlled by separate waveform sequences with different phases. This segmentation allows independent timing control of drop formation in each group, enabling synchronization with the common charging electrode waveform to prevent cross-talk artifacts while maintaining device simplicity
Solution Approach 2:
The system employs periodic charging electrode waveforms with specific phases that correspond to the periodic drop formation waveforms. By applying periodic actions with carefully controlled phase relationships, drops from both nozzle groups break off at synchronized times during specific phases of the charging waveform, eliminating cross-talk while using a single charging electrode
2Productivity
If drop formation waveforms are applied to all nozzles simultaneously, then productivity is maintained, but cross-talk artifacts are produced
Solution Approach 1:
The system uses periodic drop formation waveforms with carefully controlled phase differences between the two nozzle groups. The phase-shifted periodic waveforms ensure that drops from different nozzle groups break off at different times within the periodic cycle, synchronizing with the charging electrode phases to prevent cross-talk while maintaining high-speed continuous printing
Solution Approach 2:
The system changes the timing parameter (phase) of the drop formation waveforms for the two nozzle groups relative to each other and to the charging electrode waveform. By adjusting these phase parameters, the drop break-off times are synchronized with the appropriate phases of the charging waveform, eliminating cross-talk artifacts while preserving printing speed
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 reduces cross-talk artifacts and enhances print quality by synchronizing drop break-off times and energies, ensuring accurate deflection and reduced formation of diffuse ink spots, thereby improving print resolution and consistency.
Implementation Method 1
a drop formation device associated with each of the plurality of nozzles... modulate the liquid jet ejected from the particular nozzle to selectively cause portions of the liquid jet to break off into a pair of drops
Implementation Method 2
drop formation device... modulate the liquid jet ejected from the particular nozzle to selectively cause portions of the liquid jet to break off
Implementation Method 3
providing a charging device including: a common charging electrode positioned in proximity to the liquid jets ejected through both the first and second groups of nozzles... providing a varying electrical potential between the charging electrode and the liquid jets
Implementation Method 4
providing a deflection device which causes the printing drops having the first printing-drop charge state to travel along a different path from the non-printing drops having the second non-printing-drop charge state
Data Source
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AI summary
An inkjet printhead includes two groups of interleaved nozzles. First and second sets of drop-formation waveforms are associated with the groups of nozzles to selectively cause portions of a liquid jet to break off into drops. A timing delay device time-shifts the second-group waveforms relative to those associated with the first-group waveforms. A charging-electrode waveform having portions with first and second potentials is provided to a charging electrode. The waveform energies of the second-group waveforms is larger than the waveform energies of the corresponding first-group waveforms so that printing drops break off from the liquid jets while the charging-electrode is at the first potential, and non-printing drops break off from the liquid jets while the charging-electrode is at the second potential.