Multi-waveform Inkjet Nozzle Correction for Print Uniformity
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Solution Overview
Problem
State-of-the-art industrial print heads use a single waveform for all nozzles, leading to performance inconsistencies and common print defects such as drop volume variation, drop velocity differences, and print density issues due to variations in nozzle performance attributes.
Innovation Solution
Generating a set of discrete waveforms to optimize nozzle performance by assigning specific waveforms to each nozzle based on its unique attributes, using dithering to smooth transitions and correct defects, and employing empirical data from test patterns to refine waveform allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single identical waveform is used to drive all nozzles in the print head, then the device complexity is reduced and ease of manufacture is improved, but the manufacturing precision and uniformity of nozzle performance deteriorate
Solution Approach 1:
The patent divides the single waveform into multiple discrete waveforms (e.g., 4-16 different waveforms) and assigns different waveforms to different nozzles or nozzle groups based on their individual performance characteristics. This segmentation allows each nozzle to be optimized independently while maintaining a manageable finite set of waveforms for practical implementation.
Solution Approach 2:
The patent applies local quality by tailoring the waveform characteristics (amplitude, duration, shape) to match the specific performance attributes of individual nozzles or nozzle groups. Nozzles with different velocity, directionality, or drop volume characteristics receive customized waveforms from the finite set, ensuring each nozzle operates at optimal performance rather than using a uniform waveform for all nozzles.
2Manufacturing precision
If different waveforms are assigned to individual nozzles to optimize performance uniformity, then the manufacturing precision and nozzle performance uniformity are improved, but the device complexity increases
Solution Approach 1:
The patent creates a finite set of discrete waveforms that serves multiple nozzles or nozzle groups, rather than creating a unique waveform for each individual nozzle. This multi-functionality approach reduces the total number of waveforms needed while still achieving performance optimization across all nozzles, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent applies waveform correction to select nozzles or nozzle groups that exhibit performance variations beyond a threshold, rather than uniformly applying different waveforms to all nozzles. This partial action approach focuses computational and implementation resources only where needed, reducing overall system complexity while maintaining performance uniformity where it matters most.
3Ease of operation
If a finite set of discrete waveforms is used instead of continuous variable waveforms, then the device complexity is reduced and ease of operation is improved, but the manufacturing precision may be limited
Solution Approach 1:
The patent varies key parameters of the discrete waveforms (amplitude, pulse width, rise time, fall time) to create a finite set of distinguishable waveform types that can effectively compensate for nozzle performance variations. By strategically selecting and optimizing these parameters within the discrete waveforms, the system achieves sufficient precision for practical manufacturing while maintaining ease of operation through a manageable finite set.
Data Source
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AI summary
The uniformity of performance of inkjet nozzles within a print head containing a plurality of said nozzles is optimized by characterizing one or more performance attributes of the nozzles within said print head. A waveform set is generated that comprises a plurality of waveforms to compensate for variations of the one or more performance attributes among the nozzles. One of the waveforms within the waveform set is assigned to each nozzle to optimize the one or more performance attributes of each nozzle relative to each other nozzle in the print head. Based upon the waveform assigned to each nozzle, each nozzle in the print head responds substantially uniformly relative to each other nozzle in the print head.