Wide Format Printer Cross-Process Calibration Using Overlapping Scan Sections
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Solution Overview
Problem
Wide format printers face challenges in achieving uniform print density across the printing width due to non-uniformity in scanner illumination, which leads to streaks in prints, especially for images with large uniform areas, as existing calibration methods are inadequate and often require expensive or unavailable wide scanners.
Innovation Solution
The method involves printing test patterns across the entire printing width, dividing them into sections that overlap in the cross-process direction, scanning these sections with a narrower scanner, and using a processor to calculate and adjust response curves to compensate for non-uniformity, thereby calibrating the printer's cross-process characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a wide scanner is used to scan the entire printing width, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent divides the wide test pattern into multiple narrower sections that can be scanned individually by a standard scanner. Each section is scanned separately and then the results are combined through overlapping region analysis, allowing a narrow scanner to measure across a wide printing width without requiring a wide-format scanner.
Solution Approach 2:
The patent merges multiple individual scan results into a single combined response curve. By scanning multiple overlapping sections and combining their data through processor analysis, the system achieves comprehensive cross-process measurement coverage that would require a wide scanner to obtain in a single pass.
2Device complexity
If test pattern areas are scanned individually with a narrow scanner, then device complexity is reduced, but measurement precision deteriorates due to scanner illumination non-uniformity
Solution Approach 1:
The patent introduces the process direction as a third dimension to solve the illumination non-uniformity problem. By positioning test pattern areas at different process direction locations and scanning them individually, the system creates overlapping regions that allow comparison across different illumination conditions, enabling correction of scanner non-uniformity through multi-dimensional data analysis.
Solution Approach 2:
The patent uses overlapping test pattern areas to create a feedback mechanism for correcting scanner non-uniformity. The processor analyzes the overlapping regions between adjacent test pattern scans and uses this information to calculate correction factors that compensate for illumination variations, allowing the system to self-correct scanner non-uniformity through iterative measurement and adjustment.
3Measurement precision
If test pattern areas overlap in the cross-process direction, then measurement precision is improved through better calibration, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by creating test pattern areas with specific local characteristics - each area is positioned at different cross-process locations with controlled overlaps. The overlapping regions provide local calibration data that is specifically tailored to each area's illumination conditions, enabling precise local corrections without requiring uniform conditions across the entire printing width.
Data Source
AI summary
Methods and systems print test patterns in different test pattern areas on print media using a printer to produce a printed item. The printer has a printing width in a cross-process direction, and each of the test pattern areas is in a different cross-process location of the printing width. The test pattern areas are distributed across the entire printing width, and each of the test pattern areas partially overlaps at least one other test pattern area in the cross-process direction. Next, these methods and systems individually scan the sections of the printed item using a scanner that has a scanning width that is less than the printing width. This produces individual scans of the test pattern areas. The widths of the test pattern areas are equal to or less than the scanning width. Then, these methods and systems can calibrate cross-process characteristics of the printer based on the scans.