Nozzle Sharing Ratio Correction for Overlapping Print Banding
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Solution Overview
Problem
Existing image processing methods for printing, such as partial overlapping (POL) printing, fail to effectively reduce banding due to color differences in overlapping regions, despite correcting ink injection ratios, leading to observable white and black lines.
Innovation Solution
The method involves correcting the sharing ratios of nozzle groups to exceed 100% in overlapping image regions and adjusting the color conversion table to ensure accurate color representation, thereby addressing concentration and color difference issues in print images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ink injection ratio is corrected in overlapping regions, then banding due to concentration differences is reduced, but color differences and banding in overlapping regions remain observable
Solution Approach 1:
The patent changes the parameter of sharing ratio from the conventional 50/50 split to an unequal distribution (e.g., 60/40 or 70/30) in overlapping regions. This parameter change allows one head to deposit more ink while the other deposits less, compensating for the dot coverage reduction and preventing both concentration and color differences in the overlapping regions.
2Manufacturing precision
If sharing ratio is increased to compensate for dot coverage reduction, then concentration uniformity improves, but color differences between overlapping and non-overlapping regions increase
Solution Approach 1:
The patent applies local quality by implementing different sharing ratios for different nozzle groups within the same overlapping region. Specifically, nozzles from the first head and nozzles from the second head are assigned different sharing ratios (e.g., 60% and 40%) to locally compensate for dot coverage reduction while maintaining overall color consistency through coordinated control.
3Manufacturing precision
If unequal sharing ratio is applied to nozzle groups, then color differences in overlapping regions are reduced, but ink consumption and dot coverage control become more complex
Solution Approach 1:
The patent implements dynamic control by adjusting the sharing ratio based on the specific overlapping conditions and dot coverage reduction程度. The control unit dynamically determines the appropriate sharing ratio distribution between nozzle groups, allowing the system to adapt to varying printing conditions while maintaining color uniformity without requiring complex manual configuration.
Data Source
AI summary
An image processing method for generating printing data includes correcting, in accordance with a degree of reduction in a dot coverage below a predetermined dot coverage in a region that undergoes printing in an overlapped manner by a first nozzle group and a second nozzle group, at least either of a first sharing ratio for the first nozzle group sharing positions of dots to be formed in an overlapping image region and a second sharing ratio for the second nozzle group sharing positions of dots to be formed to allow a total ratio of the first sharing ratio and the second sharing ratio to exceed 100%, and correcting a color conversion table based on the first sharing ratio and the second sharing ratio, after the correcting of at least either of the first sharing ratio and the second sharing ratio.