Inkjet Landing Zone Printing With Multi-Pass Offset Uniformity
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Solution Overview
Problem
Inkjet printing methods struggle to achieve uniform and artifact-free results due to nozzle variations, leading to visible strip formation and Moiré effects, especially when printing RGB patterns on e-paper displays with varying pixel sizes and positions.
Innovation Solution
The method involves printing individual patterns in multiple passes with partial patterns in each pass, and laterally offsetting the print head and substrate between passes to compensate for nozzle variations, ensuring uniform coverage without overlapping printed areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the exact same number of inkjet drops are placed in each landing zone, then manufacturing consistency is maintained, but visible strip formation occurs due to nozzle variations
Solution Approach 1:
The printing process is divided into multiple passes, where each pass prints only a subset of the required patterns. This segmentation allows different nozzles to be used for different pattern groups, distributing the impact of any single defective nozzle and preventing continuous strip formation across the entire substrate.
Solution Approach 2:
The system dynamically selects which nozzles print which patterns in each pass, rather than assigning fixed nozzle-pattern relationships. This dynamic allocation allows the system to adapt to nozzle performance variations and compensate for defects by redistributing printing tasks across multiple passes.
2Manufacturing precision
If multiple passes are used to print individual patterns, then uniformity is improved by compensating for nozzle variations, but printing time increases
Solution Approach 1:
In each pass, only a partial set of patterns is printed rather than completing all patterns. This partial action approach allows the system to achieve uniformity through multiple passes while optimizing the distribution of printing tasks to minimize total processing time compared to sequential single-nozzle printing.
3Area of stationary object
If a high number of landing zones are printed, then complete coverage is achieved, but Moiré effects become visible due to position fluctuations
Solution Approach 1:
The printing of numerous landing zones is segmented into multiple passes with different nozzle assignments. This segmentation breaks up the coherence of position fluctuations that would otherwise accumulate across the entire printed area, preventing Moiré effect formation while maintaining complete coverage.
4Ease of manufacture
If the print head nozzle positions are fixed relative to the substrate grid, then positioning precision is simplified, but visible artifacts occur due to nozzle position deviations
Solution Approach 1:
Instead of using fixed nozzle-to-landing-zone assignments, the system dynamically determines which nozzles print which zones in each pass. This dynamic approach compensates for position deviations by allowing the control system to adapt assignments based on actual nozzle positions, maintaining alignment accuracy without requiring precise mechanical positioning.
Data Source
AI summary
The invention relates to a method for printing on a substrate by means of inkjet printing, in which method landing zones are provided on the substrate in a landing zone grid consisting of landing zone columns and landing zone rows, and the landing zones are each printed on using an individual pattern consisting of one or more drops by means of one or more print head nozzles of a print head, wherein the print head nozzles are moved over a surface of the substrate along an imaginary nozzle path during printing. The invention also relates to a device for printing on a substrate comprising a landing zone grid consisting of landing zone columns and landing zone rows by means of inkjet printing. In order to provide a method and a device for printing on a substrate by means of inkjet printing, which method and device allow a substrate to be printed on efficiently and simply, with the print result being particularly uniform and without unwanted artefacts and in particular the printed surface being free from lines and Moiré effects, in the method landing zones are provided on the substrate in a landing zone grid consisting of landing zone columns and landing zone rows, and the landing zones are each printed on using an individual pattern consisting of drops by means of print head nozzles of a print head, wherein the print head nozzles and the surface of the substrate are moved relative to one another along an imaginary nozzle path during printing. All individual patterns of a print nozzle path are printed in multiple passes, wherein in each pass only parts of individual patterns and/or only some of all individual patterns are printed along the nozzle path in landing zones, and in at least one subsequent pass missing parts of individual patterns or further entire individual patterns are printed in incomplete or empty landing zones. In addition, between the individual passes, the print head and the surface of the substrate are moved relative to one another laterally to the nozzle path by a lateral offset.