Inkjet Printing With Wetting Spread Ink for Defective Nozzles
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Solution Overview
Problem
Conventional inkjet printing apparatuses using UV ink face issues with uneven density and color due to individual nozzle variations and defective nozzles, leading to insufficient dot sizes and quality defects in printed images, especially in high-density regions.
Innovation Solution
The apparatus employs a configuration with three inkjet heads, where a third inkjet head ejects a wetting spread ink (white or transparent) upstream to enhance the wetting spread range, allowing correction regions to be determined based on defective nozzles and overlapping inkjet head regions, ensuring enhanced print quality by adjusting ink ejection patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nozzle-defect correction is performed to compensate for defective nozzles, then ink coverage is improved, but dot size becomes insufficient in high-density regions
Solution Approach 1:
The patent applies preliminary action by ejecting a wetting spread ink (white or transparent) before the color inks to prepare the printing medium surface. This pre-treatment enhances the wetting spread range of subsequent color inks, ensuring they achieve sufficient dot sizes even when compensating for defective nozzles. The wetting spread ink is ejected in advance to modify the surface properties, allowing color inks to spread more effectively and cover larger areas.
Solution Approach 2:
The wetting spread ink acts as an intermediary substance between the printing medium and the color inks. By introducing this intermediate layer, the patent enables color inks to achieve better wetting and spread characteristics. The wetting spread ink modifies the surface energy of the printing medium, creating favorable conditions for subsequent color ink deposition and ensuring adequate dot formation even in compensation scenarios.
2Reliability
If conventional nozzle-defect correction is used, then missing dots are addressed, but uneven density and color occur due to individual nozzle variations
Solution Approach 1:
The patent applies local quality by determining specific correction regions where defective nozzles are located and applying enhanced ink ejection only to those localized areas. Instead of uniformly increasing ink ejection across the entire printing surface, the system identifies problematic regions and targets them specifically. This localized approach maintains density uniformity in non-defective areas while ensuring adequate coverage in defective regions.
Solution Approach 2:
The wetting spread ink is ejected in advance to predetermined correction regions before color inks are deposited. This preliminary action prepares specific areas where defective nozzles exist, ensuring that when color inks are subsequently ejected to compensate for missing dots, they achieve sufficient spread and density in those targeted regions without affecting other areas.
3Manufacturing precision
If wetting spread ink is ejected to enhance dot size, then print quality improves, but ink consumption increases
Solution Approach 1:
The patent minimizes ink consumption by applying the wetting spread ink only to predetermined correction regions where defective nozzles are located, rather than uniformly across the entire printing surface. The system identifies specific areas requiring enhancement and targets them selectively. This localized application strategy maintains print quality in defective regions while avoiding unnecessary ink usage in areas that do not require correction.
Solution Approach 2:
The patent applies partial action by using the wetting spread ink only to the extent necessary for correcting defective nozzle regions. Rather than applying excessive ink coverage across the entire printing surface, the system determines the minimum required correction regions and applies the wetting spread ink only there. This ensures adequate dot size and print quality in problematic areas while minimizing overall ink consumption.
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 configuration effectively suppresses defects in printed images by ensuring larger dot sizes and improved uniformity, even in the presence of defective nozzles, resulting in higher-quality print products.
Implementation Method 1
a first ink has a larger wetting spread range on the printing medium when the first ink is ejected onto the third ink on the printing medium than when the first ink is ejected directly onto the printing medium
Data Source
AI summary
To suppress the occurrence of image defects caused by a defective nozzle and other factors in a printed image on a base material by an inkjet printing apparatus, a region to be corrected in the image is determined. When the region to be corrected is a single-color high-density region to be formed by ejecting a single-color ink, or when the region is a mixed-color high-density region to be formed using two or more color inks, and the amount of ink in the color from the defective nozzle has a high total area coverage percentage, printing data is corrected such that the color ink ejection to the region is performed after white ink or transparent ink is ejected. Based on the corrected printing data, the printed image is formed on the base material, thereby suppressing the occurrence of image defects caused by the defective nozzle and other factors.