Inkjet Printing With Correction Aid Ink for Nozzle Defects
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Solution Overview
Problem
Conventional inkjet printing apparatuses using UV ink face challenges in achieving high-quality prints due to nozzle variations and ejection failures, particularly when printing narrow linear patterns like characters or barcodes, as existing correction methods fail to adequately address dot missing and ink uniformity issues.
Innovation Solution
The apparatus employs a correction aid inkjet head positioned upstream, ejecting a correction aid ink that increases the wetting spread range of the primary ink, allowing for effective correction of defective nozzles by determining specific correction regions and executing ink ejection strategies to mitigate image defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional nozzle-defect correction is performed by ejecting ink through adjacent nozzles to compensate for defective nozzles, then dot missing is partially corrected, but the wetting spread range is insufficient to adequately rectify image defects in high-density printing regions
Solution Approach 1:
The patent introduces a correction aid ink as an intermediary substance between the printing medium and the primary ink. This correction aid ink, when ejected onto the printing medium, creates a surface that enhances the wetting spread range of subsequently ejected primary ink from adjacent nozzles. The correction aid ink acts as a mediator that facilitates better ink distribution and coverage, thereby adequately correcting image defects in high-density printing regions where conventional methods fail.
2Manufacturing precision
If correction aid ink is ejected into the entire correction region to maximize wetting spread, then defective nozzle compensation is improved, but ink bleeding occurs at the boundaries of narrow linear patterns
Solution Approach 1:
The patent applies local quality by selectively ejecting correction aid ink only into specific regions within the correction region, rather than uniformly across the entire area. The correction region determination portion identifies and excludes boundary regions of narrow linear patterns from correction aid ink ejection. This localized approach ensures that correction aid ink is applied only where it will effectively compensate for defective nozzles without causing ink bleeding at pattern boundaries, thereby maintaining both defect correction and pattern integrity.
3Manufacturing precision
If density correction is applied to all nozzles uniformly, then individual nozzle variations are corrected, but defective nozzles cannot be adequately compensated due to insufficient ink ejection from adjacent nozzles
Solution Approach 1:
The patent applies preliminary action by ejecting correction aid ink onto the printing medium before ejecting the primary ink from adjacent nozzles. This preparatory step modifies the surface properties of the printing medium in advance, creating conditions that enhance the wetting spread range of the primary ink. By performing this action beforehand, the system compensates for the insufficient ink ejection capability of adjacent nozzles, ensuring that adequate ink coverage is achieved even when defective nozzles cannot eject properly.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances print quality by compensating for defective nozzles, ensuring uniform ink distribution and preventing ink bleeding, even in high-density regions, thereby producing satisfactory images with narrow linear patterns.
Implementation Method 1
the first ink has a larger wetting spread range on the printing medium when the first ink is ejected onto the correction aid ink on the printing medium than when the first ink is ejected directly onto the printing medium
Data Source
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AI summary
For each individual correction area to be corrected so as to suppress image defects caused by dot missing in the printed image to be formed on the base material by the inkjet printing apparatus, it is determined whether or not to use a correction aid ink (white or transparent ink) for the correction of that individual correction area (S121, S141). A correction execution area is determined by removing pixel rows corresponding to a predetermined thinning number (e.g. one pixel row) from the opposite ends of an individual correction area determined to be corrected using the correction aid ink (S123, S143). The printing data is corrected such that a color ink is ejected in the correction executed area to form the printed image after the correction aid ink is ejected (S128, S148). Based on such corrected printing data, the printed image is formed on the base material.