Electrostatic Printer Drop Placement Error Reduction
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Solution Overview
Problem
Electrostatic interactions between adjacent drops in continuous inkjet printing systems lead to drop placement errors and limited print resolution due to the requirement for individually addressable nozzles and common charge electrodes, resulting in degraded print quality and reduced print margin.
Innovation Solution
The system employs a nozzle array with interleaved nozzles and a common charge electrode, where drop formation timing is controlled to create sequences of print and non-print drops with different charge states, using a timing delay to shift the drop formation waveforms and synchronize them with a charge electrode waveform, allowing for separate deflection paths and reduced electrostatic interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If individually addressable nozzles and common charge electrodes are used in continuous inkjet printing, then drop placement flexibility is improved, but electrostatic interactions between adjacent drops cause placement errors and limit print resolution
Solution Approach 1:
The patent divides the nozzle array into multiple independently controllable groups, where each group can be addressed separately. This segmentation allows selective activation of nozzle groups to reduce electrostatic interactions between adjacent charged drops, thereby improving print resolution while maintaining placement flexibility through independent group control.
Solution Approach 2:
The patent implements periodic charging patterns where charge electrodes are activated in alternating sequences rather than simultaneously. This periodic action creates time-separated charge applications that reduce electrostatic interference between adjacent drops, enabling higher precision printing while preserving the ability to place drops flexibly across the print area.
2Device complexity
If common charge electrodes are used for multiple nozzles, then device complexity is reduced, but electrostatic interactions between drops increase causing placement errors
Solution Approach 1:
The patent segments the common charge electrode system into multiple independently controllable electrode groups, each serving specific nozzle groups. This maintains the benefit of shared electrode infrastructure while enabling selective activation to minimize electrostatic interactions, thereby preserving placement accuracy without significantly increasing control complexity.
Solution Approach 2:
The patent employs periodic activation sequences for common charge electrodes, where electrodes are switched on and off in coordinated patterns. This allows the system to maintain simplified common electrode architecture while using time-based control to reduce electrostatic interference, preserving drop placement accuracy without requiring individually addressed electrodes for each nozzle.
3Manufacturing precision
If nozzles are closely spaced to increase print resolution, then print resolution is improved, but electrostatic interactions between adjacent drops increase causing placement errors
Solution Approach 1:
The patent uses periodic charging patterns where adjacent nozzles are activated in alternating sequences with time delays. This temporal separation reduces electrostatic interactions between drops from closely spaced nozzles, enabling high print resolution through close nozzle spacing without suffering from increased electrostatic interference.
Solution Approach 2:
The patent divides closely spaced nozzles into separate controllable groups that can be activated selectively. This segmentation allows the system to maintain close physical spacing for high resolution while using independent group control to minimize simultaneous charging of adjacent drops, thereby reducing electrostatic interactions.
4Device complexity
If charge electrodes are placed close to nozzles for compact design, then device compactness is improved, but electrostatic interactions between drops increase
Solution Approach 1:
The patent implements periodic activation patterns for compactly placed charge electrodes, where electrodes are switched in sequences that separate the charging of adjacent drops in time. This allows the system to maintain compact electrode-nozzle spacing while using temporal separation to reduce electrostatic interactions between drops.
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, reduces complexity in nozzle control, and increases the spacing between charge electrodes, leading to higher print resolution and improved print margin by minimizing electrostatic interactions and allowing longer throw distances.
Implementation Method 1
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 2
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
AI summary
A group timing delay device is provided to shift the timing of drop formation waveforms supplied to drop formation devices of nozzles of one of first and second groups so that print drops formed from nozzles of the first and second 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 formed from the nozzles of the first and second group and a source of varying electrical potential between the charge electrode and liquid jets. The source of varying electrical potential provides a charging waveform that is independent of print and non-print drop patterns. The charging device is synchronized with the drop formation device and the group timing delay device to produce a print drop charge state on print drops and a non-print drop charge state on non-print drops.