Electrostatic Printer Drop Placement Error Reduction
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Solution Overview
Problem
Continuous inkjet printing systems face challenges with drop placement accuracy due to electrostatic interactions between adjacent drops, leading to reduced print resolution and quality, particularly in high-density nozzle arrays where electrostatic cross-talk causes splay errors and increased throw distance requirements.
Innovation Solution
The system employs an individually addressable nozzle array with a common charge electrode and synchronized drop formation and charging waveforms to create sequences of print and non-print drops, using a timing delay to shift drop formation waveforms and charge electrode waveforms, allowing for differential deflection and reduced electrostatic interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common charge electrode is used with a nozzle array, then device complexity is reduced, but drop placement accuracy deteriorates due to electrostatic cross-talk between adjacent drops
Solution Approach 1:
The nozzle array is divided into multiple independently controllable groups, with each group having its own drop formation waveform timing. This segmentation allows differential deflection of drops from different nozzles, compensating for electrostatic cross-talk effects and improving drop placement accuracy while maintaining a common charge electrode structure.
2Productivity
If nozzles are arranged in high-density arrays, then productivity increases, but drop placement accuracy deteriorates due to increased electrostatic interactions
Solution Approach 1:
The system dynamically adjusts the timing of drop formation waveforms for different nozzle groups based on real-time printing requirements. This dynamic timing control enables the system to compensate for electrostatic interactions between adjacent drops in high-density arrays, maintaining drop placement accuracy while achieving high productivity through increased nozzle density.
3Manufacturing precision
If electrostatic deflection is used to selectively deflect drops, then manufacturing precision is improved, but device complexity increases due to additional electrostatic field regions
Solution Approach 1:
The common charge electrode serves multiple functions: it charges all drops uniformly and works in conjunction with the differential timing control to achieve selective deflection. This multi-functionality eliminates the need for individual charge electrodes at each nozzle, reducing device complexity while maintaining precise dot positioning through the combined electrostatic deflection mechanism.
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 improves drop placement accuracy, increases print margin, and simplifies control signals, reducing complexity and electrostatic interactions, thereby enhancing print quality and resolution.
Implementation Method 1
Each of the drop formation devices is provided with a sequence of drop formation waveforms to modulate the liquid jets to selectively cause portions of the liquid jet to break off into one or more pairs of drops
Implementation Method 2
A charging electrode structure is positioned at the nominally constant break-off location so as to induce an input image data-dependent amount of electrical charge on the drop at the moment of break-off
Implementation Method 3
The charged drops are then directed through a fixed electrostatic field region causing each droplet to deflect by an amount dependent upon its charge to mass ratio
Data Source
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AI summary
A group timing delay device shifts the timing of drop formation waveforms supplied to drop formation devices of one of first and second nozzle groups so that print drops from the nozzle groups are not aligned relative to each other along a nozzle array direction. A charging device includes a common charge electrode associated with liquid jets from the nozzle groups and a source of varying electrical potential between the charge electrode and liquid jets which provides a charging waveform that is independent of a print and non-print drop pattern. The charging device is synchronized with the drop formation devices and the group timing delay device to produce a print drop charge state on print drops of a drop pair, a first non-print drop charge state on non-print drops of the drop pair, and a second non-print drop charge state on third drops.