Halftone Calibration Logic for Print Head Uniformity
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Solution Overview
Problem
Existing print engine technologies face challenges in correcting cross-web spatial non-uniformity, particularly at the junctions between print heads and within printheads, as current methods fail to account for gaps or overlaps between print head segments, leading to incomplete nozzle compensation and interactions between nearby nozzles.
Innovation Solution
A printing system that includes a halftone calibration logic executed by processors to generate measurement data for pel forming elements, using inverse transfer functions to produce uniformity-compensated halftones, which account for each nozzle's unique characteristics and interactions, thereby addressing the non-uniformity issues across the print medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If each print head nozzle is corrected using interpolated reflectance measurements independently, then individual nozzle compensation is achieved, but non-uniformities at junctions between print heads and within printheads persist due to gaps or overlaps not being accounted for
Solution Approach 1:
The patent combines measurements from multiple nozzles to create composite waveforms that represent the cumulative effect of adjacent nozzles. By merging the transfer functions of individual nozzles into group transfer functions, the system accounts for interactions at junctions between print head segments, thereby improving print output uniformity while maintaining individual nozzle compensation accuracy.
2Measurement precision
If fiducial marks at print head segment boundaries are used to locate individual nozzles, then precise nozzle positioning is achieved, but print head segment boundaries remain uncontrolled and corrections to nearby nozzles continue to interact
Solution Approach 1:
The patent applies different correction strategies to different regions: individual nozzle transfer functions are used for nozzles away from boundaries, while group transfer functions that model the cumulative effect of multiple nozzles are applied at segment boundaries. This localized approach maintains precise nozzle positioning while controlling the uncontrolled interactions at segment boundaries.
3Ease of manufacture
If independent nozzle compensation is performed without considering adjacent nozzles, then individual nozzle characteristics are corrected, but interactions between nearby nozzles cause remaining non-uniformities
Solution Approach 1:
The patent segments the print head into groups of adjacent nozzles, where each group is treated as a unit with its own composite transfer function. This segmentation allows the system to account for interactions between nearby nozzles while maintaining a manageable correction process, improving print output uniformity without excessive complexity.
Data Source
AI summary
A printing system is disclosed. The printing system includes at least one physical memory device to store halftone calibration logic and one or more processors coupled with the at least one physical memory device to execute the halftone calibration logic to receive print image measurement data corresponding to a first halftone design associated with each of a plurality of pel forming elements, generate measurement data for each of the pel forming elements based on the print image measurement data, generate a uniformity compensated halftone for each of the pel forming elements based on inverse transfer functions corresponding to each of the pel forming elements and the first halftone design and transmit the uniformity compensated halftone for each of the pel forming elements.