Image Processing Apparatus Nozzle Misalignment Density Control
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Solution Overview
Problem
Inkjet printing systems face image deterioration due to misalignment of printing positions between nozzle groups, leading to density unevenness and increased data processing requirements, which are costly and inefficient.
Innovation Solution
An image processing apparatus and method that generates separate quantization data for each nozzle group using distinct mask patterns, ensuring that the sum of dots in the print data correlates with the original pixel value, thereby maintaining tone values and reducing density variations caused by misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-value quantization data is created for each print head and binarized separately, then robustness to misalignment is improved, but data amount increases and processing cost increases
Solution Approach 1:
The patent divides the image processing into two stages: first creating a single multi-value quantization map for the entire image, then separately binarizing for each print head using mask patterns. This segmentation allows robustness improvement without proportionally increasing overall data amount, as the multi-value quantization data is shared across multiple print heads.
Solution Approach 2:
The patent applies different binarization parameters and mask patterns to different print heads based on their specific characteristics and positions. Each print head receives customized processing parameters optimized for its local requirements, improving robustness to misalignment while maintaining efficient data management through the shared multi-value quantization foundation.
2Productivity
If multiple nozzle groups are used for high-speed printing, then printing speed is improved, but misalignment of printing positions occurs causing density unevenness
Solution Approach 1:
The patent performs multi-value quantization on the entire image before dividing it among multiple nozzle groups. This preliminary processing establishes a consistent tonal reference framework that guides subsequent binarization for each nozzle group, ensuring that even when printed at high speed with potential misalignment, the density remains uniform across the composite image.
Solution Approach 2:
The patent creates mask patterns that represent ideal printing positions and uses these as templates for each nozzle group. By copying and adapting these reference patterns to each print head's specific position and characteristics, the system maintains printing position alignment accuracy even when using multiple nozzle groups for high-speed printing.
Data Source
AI summary
First quantization data for printing by the first nozzle group and second quantization data for printing by the second nozzle group are generated based on multi-valued data. By use of mask patterns, first print data and second print data are generated based on the first quantization data and the second quantization data. The first mask pattern for generating first print data and the second mask pattern for generating second print data are formed so as to include a pixel in which printing of a dot is allowed in both and a pixel in which printing of a dot is not allowed in both. The pixel value of each pixel indicated by the multi-valued data has a correlation with the sum of the number of dots indicated by the first print data and the number of dots indicated by the second print data in the area corresponding to each pixel.