Fluorescent Ink for Chromatic Substrate Color Reproduction
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Solution Overview
Problem
Current inkjet printing technologies face challenges in reproducing high-definition color images on chromatic color printing substrates like cardboard, as they often result in unnatural colors and low color reproducibility due to absorption of light in specific wavelength bands, especially when using only color inks.
Innovation Solution
An ink image generating method that selects and uses a fluorescent ink suitable for enhancing color reproducibility by calculating colorimetric differences between the target color and the substrate, and jetting the fluorescent ink at specific positions and amounts to complement the color ink, thereby improving reflectance in critical wavelength regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If color inks are jetted on chromatic color substrates to form color images, then the substrate can be utilized for printing, but light is absorbed in specific wavelength bands causing poor color reproducibility
Solution Approach 1:
A white ink containing fluorescent whitening agents is introduced as an intermediary layer between the chromatic substrate and the color inks. This intermediary layer compensates for the substrate's light absorption characteristics by emitting fluorescent light, thereby improving color reproducibility without changing the substrate itself
Solution Approach 2:
The optical parameters of the printing system are changed by introducing fluorescent whitening agents that alter the light reflection and emission characteristics. This changes the way light interacts with the printed image, compensating for the substrate's absorption in specific wavelength bands
2Manufacturing precision
If white ink is used for substrate treatment to improve color reproducibility, then color images can be reproduced accurately, but the ground color of the substrate is changed to white background
Solution Approach 1:
Instead of uniformly treating the entire substrate with white ink, the fluorescent whitening agents are applied locally in the form of droplets positioned beneath or adjacent to the color ink droplets. This local treatment improves color reproducibility only where needed while preserving the substrate's original ground color in other areas
3Manufacturing precision
If fluorescent ink is jetted together with color ink to enhance color reproducibility, then specific color reproduction is improved, but the device complexity increases
Solution Approach 1:
Instead of using fluorescent inks for all color channels, the invention selectively applies fluorescent ink only for specific color channels where the substrate's light absorption causes the greatest color reproduction problems. This partial application reduces the complexity increase while still achieving improved color reproducibility for critical colors
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 method ensures high color reproducibility of specific colors on chromatic color substrates by adjusting the droplet jetting position and amount of fluorescent ink, resulting in improved visibility and color accuracy of ink images.
Implementation Method 1
JP2005-125643A proposes an image forming method using a white ink containing white pigments and an ink containing a fluorescent whitening agent
Data Source
AI summary
Provided is an ink image matter generating method for selecting a fluorescent ink by performing (a) a process of color-measuring a target color which is a target of color reproduction on a medium and the medium on which an inkjet color ink for color reproduction of the target color is printed; (b) a process of calculating a difference between a colorimetric value of the target color and a colorimetric value of the medium on which the color ink is printed; and (c) a process of selecting a fluorescent ink for reducing the difference between the colorimetric value of the target color and the colorimetric value of the medium on which the color ink is printed, from fluorescent inks that are set in advance, and jetting droplets of the selected fluorescent ink together with the color ink, or after the droplets of the color ink are jetted to cause the fluorescent ink to exist on a surface of an ink image matter, thereby making it possible to select and use an appropriate fluorescent ink with respect to a specific color of which the color reproducibility cannot be ensured using only a color ink in inkjet printing on a medium which is a printing substrate and to ensure high color reproducibility ensuring high color reproducibility for the specific color.