Page-wide array printing nozzle redundancy
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Solution Overview
Problem
In page-wide array printing apparatuses, visible defects such as image quality artefacts occur due to overlap areas between printing dies, particularly caused by high resolution and small drop volume, dot placement errors, and swath height errors, which are exacerbated by repetition and inaccuracies in die positioning.
Innovation Solution
The implementation of random split weaving masks that provide nozzle redundancy, allowing for flexible operation of nozzles in overlap areas to compensate for positioning errors and swath height variations, combined with high accuracy calibration in the media advance direction to minimize artefacts in the page width direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high printing resolution and small drop volume are used, then printing quality is improved, but visibility of defects in overlap areas increases
Solution Approach 1:
The patent applies different printing strategies to different regions of the substrate. In overlap areas, the system uses redundant nozzles from adjacent printing dies with modified drop placement patterns, while non-overlap areas use standard printing. This local differentiation allows high resolution printing while masking defects in sensitive overlap regions through the weaving pattern.
Solution Approach 2:
The patent converts the harmful effect of dot placement errors in overlap areas into a beneficial weaving pattern. By intentionally introducing controlled variations in drop placement and using redundant nozzles, the system transforms potential defects into an aesthetic weaving texture that masks rather than reveals positioning inaccuracies.
2Productivity
If one-pass print-mode is used, then printing speed is improved, but image quality artefacts increase due to dot placement errors
Solution Approach 1:
The patent dynamically adjusts printing parameters based on position. In overlap areas, it modifies drop volume, nozzle selection, and timing to compensate for dot placement errors while maintaining one-pass printing speed. The system changes operational parameters locally rather than using multi-pass printing, thus preserving productivity while improving precision in critical regions.
3Area of stationary object
If multiple repetitions of overlap areas occur, then coverage is improved, but visibility of defects increases
Solution Approach 1:
The patent implements periodic variation in the weaving pattern across multiple overlap repetitions. Instead of using identical drop placement patterns in each overlap area, the system varies the pattern parameters periodically, which distributes and masks defects across different positions, preventing the repetition of visible artefacts while maintaining full coverage.
4Reliability
If nozzle redundancy is implemented in overlap areas, then robustness against positioning errors is improved, but device complexity increases
Solution Approach 1:
The patent segments the printing system into distinct control zones: overlap areas with redundant nozzles and non-overlap areas with standard single-nozzle operation. This segmentation allows the system to implement complex redundancy control only where necessary, maintaining reliability in overlap regions while avoiding unnecessary complexity in other areas.
Data Source
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AI summary
A method in a page-wide array printing apparatus comprising at least first and second printing dies that overlap in a page width direction comprises the steps of calibrating the printing apparatus in a media advance direction to a higher resolution than the page width direction, the media advance direction being perpendicular to the page width direction, and using printing masks to control the operation of a plurality of nozzles in an overlap area between the first and second printing dies to reduce any visible defects caused by dot placement errors in the page width direction.