Multi-pass Ink Dot Superimposition Control for Print Quality
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image processing techniques for multi-pass printing, such as those described in Japanese Patent Laid-Open No. 2010-100017, suffer from dot pattern dispersibility issues due to misregistration and interaction between inks, leading to impaired image quality and unevenness.
Innovation Solution
An image processing apparatus that generates halftone image data by dividing density ranges of pixel values for each scan, ensuring that dot patterns from different color components are properly superimposed, with the first halftone image data printed as a layer lower than the second, maintaining dot pattern dispersibility during multi-pass printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dots corresponding to each scan are thinned out in accordance with a given fixed pattern in multi-pass printing, then the ink fixing order can be controlled to improve light resistance and suppress color unevenness, but the dispersibility of the dot pattern is impaired due to misregistration between printing scans
Solution Approach 1:
The patent segments the dot pattern formation process into multiple passes, where dots are formed in different scans rather than all at once. This segmentation allows control over ink fixing order while distributing dots across multiple printing operations, thereby maintaining dispersibility despite the multi-pass approach
Solution Approach 2:
The patent performs preliminary determination of which dots should be formed in which scan based on density requirements. By pre-planning the dot distribution across scans and ensuring proper superimposition relationships, the system maintains dot pattern dispersibility while achieving controlled ink fixing order for light resistance improvement
2Manufacturing precision
If multi-pass printing is performed with controlled ink fixing order, then light resistance and color uniformity are improved, but misregistration between scans and ink interaction locally disturb the upper layer/lower layer relationship
Solution Approach 1:
The patent applies different superimposition control strategies to different local regions and dot patterns. By evaluating each dot's position, density, and scan assignment individually, the system maintains stable superimposition relationships locally while achieving overall color uniformity across the entire image
Solution Approach 2:
The patent incorporates feedback mechanisms where the system evaluates the assigned scan numbers and superimposition relationships, then adjusts dot formation decisions to maintain stability. This feedback loop ensures that misregistration and ink interaction effects are compensated for, preserving the intended upper/lower layer relationships
3Manufacturing precision
If density ranges are divided for respective scans to control dot superimposition, then high-quality images are generated with maintained dispersibility, but the processing complexity increases
Solution Approach 1:
The patent segments the density range into multiple levels and assigns different density levels to different scans. This segmentation approach systematically controls dot superimposition to maintain dispersibility while achieving high image quality, with the added benefit that the segmented structure makes the processing more manageable despite increased complexity
Solution Approach 2:
The patent dynamically adjusts the assignment of dots to scans based on density requirements and superimposition considerations. This dynamic processing, while more complex than static approaches, enables optimal image quality and dispersibility maintenance by adapting decisions to local image characteristics
Data Source
AI summary
This invention generates a high-quality image by controlling the superimposition relationship between dots to be printed in multi-pass printing by a printhead including a plurality of printing elements. When a yellow dot is printed after printing a cyan dot in one scan in multi-pass printing, image data serving as a processing target is generated as follows. In cyan and yellow halftone image data for each scan, halftone image data having dots at a common pixel are set to correspond to a scan in which yellow dot data precedes cyan dot data. A yellow dot is printed as a layer lower than a cyan dot.