Inkjet Printing With Correction Aid Ink for Dot Missing
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Solution Overview
Problem
Inkjet printing apparatuses face challenges in forming high-quality printed images when printing narrow linear patterns such as characters or barcodes, especially when there are defective nozzles causing dot missing, as conventional nozzle-defect correction may not adequately rectify image defects in high-density regions.
Innovation Solution
The printing apparatus employs a correction aid inkjet head that ejects a correction aid ink, such as white or transparent ink, upstream of the main inkjet head. This correction aid ink increases the wetting spread range of the primary ink, allowing it to form larger dots and effectively correct image defects caused by defective nozzles, even in high-density regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional nozzle-defect correction is performed to compensate for dot missing caused by defective nozzles, then image defects are reduced, but the correction is insufficient in high-density regions such as narrow linear patterns
Solution Approach 1:
The patent introduces a correction aid ink (white or transparent) as an intermediary substance between the printing medium and the primary ink. This correction aid ink is ejected by a dedicated correction aid inkjet head upstream of the main inkjet head, creating a preparatory layer that enables subsequent primary ink to spread and form adequate dot size even when ejected from nozzles adjacent to defective ones, thereby resolving the insufficiency of conventional correction methods in high-density regions
Solution Approach 2:
The correction aid ink is ejected in advance before the primary ink deposition. This preliminary action prepares the printing medium surface by applying a substance that increases wetting spread range, ensuring that when the primary ink is subsequently ejected (especially from nozzles compensating for defective ones), it can achieve sufficient dot size and density uniformity in high-density regions like narrow linear patterns
2Manufacturing precision
If correction aid ink is ejected to increase wetting spread range and form larger dots, then dot missing is corrected effectively, but ink consumption increases
Solution Approach 1:
The correction aid ink is applied selectively only in regions where defective nozzles are detected and where correction is needed, rather than uniformly across the entire printing area. The correction aid inkjet head ejects correction aid ink at specific locations corresponding to areas affected by defective nozzles, and the primary inkjet head subsequently ejects primary ink only in these targeted correction regions, thereby minimizing overall ink consumption while achieving effective dot size uniformity in critical areas
Solution Approach 2:
The patent changes the physical-chemical parameters of the printing medium surface by applying correction aid ink that increases the wetting spread range. This parameter change allows the primary ink to spread more effectively and form adequate dot size with less primary ink consumption, as the correction aid ink creates conditions that enhance ink distribution and reduce the amount of primary ink needed to achieve proper dot size in correction regions
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 solution enables the formation of high-quality printed images with improved density uniformity and reduced image defects, even when printing narrow linear patterns, by effectively compensating for dot missing caused by defective nozzles.
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
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. 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. 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. Based on such corrected printing data, the printed image is formed on the base material.