Inkjet Printer Overlap Region Segmentation for Density Consistency
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Solution Overview
Problem
Full line type inkjet printers with connecting heads experience image density changes and graininess degradation due to medium inclination during printing, particularly in the overlap regions where nozzle arrays from multiple chips interact.
Innovation Solution
The image processing method divides the overlap region into multiple sub-regions and distributes print data such that at least one nozzle array from each chip is not used for printing in each sub-region, ensuring consistent print allowance rates across the overlap area, thereby minimizing the impact of medium inclination on print position and density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple nozzle arrays are arranged in overlap regions to increase printing coverage, then printing productivity is improved, but image quality deteriorates due to density changes and graininess when medium inclination occurs
Solution Approach 1:
The patent divides the overlap region into multiple sub-regions (first overlap sub-region and second overlap sub-region) and assigns different nozzle arrays to print in different sub-regions. This segmentation prevents multiple nozzle arrays from printing in the same location, eliminating density changes and graininess while maintaining the coverage benefits of having multiple nozzle arrays.
2Speed
If print data is distributed to all nozzle arrays in overlap regions, then printing speed is improved, but print position accuracy deteriorates due to medium inclination
Solution Approach 1:
The patent applies different printing strategies to different sub-regions within the overlap area. In the first overlap sub-region, only the first nozzle array prints, while in the second overlap sub-region, only the second nozzle array prints. This local differentiation maintains printing speed by utilizing multiple nozzle arrays while ensuring print position accuracy by preventing simultaneous printing from multiple arrays in the same location.
3Quantity of substance
If the print allowance rate is increased in overlap regions to maintain image density, then image density is improved, but graininess deteriorates due to variations in ejection characteristics
Solution Approach 1:
Instead of increasing the print allowance rate in overlap regions to maintain image density, the patent inverts the approach by excluding overlap regions from printing by certain nozzle arrays. This prevents the graininess caused by variations in ejection characteristics while maintaining image density through proper distribution of print data to non-overlapping sub-regions.
Data Source
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AI summary
There is provided an image processing method in which in a full line type inkjet printer using a connecting head having an overlap region, even if a conveyance direction of a print medium is more or less inclined, a density change or degradation of graininess is not introduced. Therefore, an image data in a non-overlap region is distributed to a plurality of nozzle arrays such that ink is ejected from all the plurality of the nozzle arrays. On the other hand, a region where a print allowance rate changes in the overlap region is divided into plural regions, and the image data is distributed to the plurality of the nozzle arrays such that these regions are located to be shifted.