Print Head Calibration via Multi-Die Color Density Scanning
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Solution Overview
Problem
Page wide array print apparatuses face challenges in achieving uniform print agent deposition across multiple print heads due to manufacturing tolerances, leading to color nonuniformity, which existing calibration techniques struggle to address effectively.
Innovation Solution
A calibration method where each die of a print head prints a calibration pattern in different colors on a single page, allowing for simultaneous scanning with multiple scanning modules to identify and adjust for density differences, ensuring uniformity without the need for multiple pages or specialized equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple pages are used for calibration (one per colorant), then measurement accuracy can be improved, but loss of time increases due to multiple scanning operations
Solution Approach 1:
The patent combines calibration patterns for multiple colorants (cyan, magenta, yellow, black) onto a single printable substrate. All calibration images are printed in one operation and scanned once, eliminating the need for separate scanning operations for each colorant while maintaining measurement accuracy through simultaneous capture of all color densities.
Solution Approach 2:
The patent arranges calibration patterns spatially across the substrate in a two-dimensional layout, with different colorant patterns positioned in different regions. This spatial arrangement allows a single scanning operation to capture all colorant data simultaneously, transforming a sequential multi-page process into a parallel single-page process.
2Measurement precision
If separate scanning operations are performed for each color, then measurement precision improves, but device complexity increases due to multiple scanning modules
Solution Approach 1:
The patent makes a single scanning module capable of measuring multiple colorants by using color separation filters or spectral analysis. The same scanning hardware performs the measurement function for all four colorants (cyan, magenta, yellow, black) by processing the reflected light through different wavelength filters or analyzing the spectral composition, eliminating the need for separate dedicated scanning modules for each color.
3Manufacturing precision
If calibration patterns are printed on multiple pages, then manufacturing precision of individual patterns improves, but productivity decreases due to repeated printing operations
Solution Approach 1:
The patent merges calibration patterns for all colorants onto a single substrate, allowing all patterns to be printed in one continuous printing operation. This eliminates repeated printing operations while maintaining pattern quality through proper spatial arrangement and ink deposition control across the entire substrate surface.
Data Source
AI summary
A print apparatus calibration method is disclosed. The method comprises printing, from each of a plurality of dies of a print head onto a printable substrate, an image in a first color according to a calibration pattern and an image in a second color according to the calibration pattern, the calibration pattern comprising a plurality of patches having a plurality of different densities. The method may comprise scanning, using a scanning unit, the images formed on the printable substrate to generate scanned image data, wherein the images in the first color are scanned by a first scanning module of the scanning unit and the images in the second color are scanned by a second scanning module of the scanning unit. The method may comprise analyzing, using processing apparatus, the scanned image data to identify any differences between printed densities of corresponding patches in different images of the same color. The method may comprise performing a calibration based on the analysis. A print apparatus and a machine-readable medium are also disclosed.