Image Forming System Screen Adjustment for Moiré Reduction
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Solution Overview
Problem
Existing image forming systems face challenges in accurately performing gradation correction due to moiré patterns caused by the relationship between the screen used for printing jobs and the scanning device's pixel arrangement, leading to variations in RGB values of gradation patterns scanned by the scanning device.
Innovation Solution
The system employs a second screen with adjusted screen lines or angles for specific colors, synchronized with the scanning device's resolution, to perform gradation correction, while using the original screen for other colors, thus minimizing moiré effects and ensuring accurate gradation correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same screen is used for both printing jobs and gradation patterns, then the printing process is simplified and consistent, but moiré patterns occur due to the relationship between the screen and the scanning device's pixel arrangement, causing inaccurate gradation correction
Solution Approach 1:
The patent applies different screen parameters (screen lines and/or screen angles) specifically for the gradation pattern compared to the printing job. This local differentiation ensures that the gradation pattern does not create moiré patterns with the scanning device's pixel arrangement, while the printing job maintains its original screen settings. This resolves the contradiction by allowing simplified overall screen configuration while achieving accurate local measurement for gradation correction.
2Measurement precision
If the screen parameters are changed to avoid moiré patterns, then gradation correction accuracy improves, but the difference between printing screen and gradation pattern screen increases
Solution Approach 1:
The patent changes specific parameters of the screen (screen lines and/or screen angles) for the gradation pattern to avoid moiré patterns with the scanning device. By adjusting these parameters within reasonable ranges, the system achieves accurate gradation correction while maintaining compatibility. The patent specifies that the difference in screen lines should be 50 lines or less and the difference in screen angle should be 15-75 degrees, ensuring the changed screen remains compatible with standard printing requirements.
Data Source
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AI summary
An image forming system includes a processor configured to perform control such that printing is performed for a specific color of a gradation pattern printed on a recording medium by using a second screen obtained by changing at least one of the number of screen lines or a screen angle of a first screen used for a printing job and printing is performed for a color other than the specific color of the gradation pattern in a same manner as the screen used for the printing job in a case where the gradation pattern is scanned by a scanning device and is gradation-corrected.