Inkjet Ink Lightfastness via Reduced Isomaltulose Fixing
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Solution Overview
Problem
Inkjet inks containing Blue No. 1 and reduced isomaltulose suffer from photodiscoloration and fading due to light exposure, especially in environments with normal humidity, leading to decreased lightfastness and visibility of printed images on tablets.
Innovation Solution
The inkjet ink formulation includes Blue No. 1 as a food dye in the range of 0.1 to 2.5 mass% and reduced isomaltulose as a fixing agent in the range of 5.7 to 16.2 times the mass of Blue No. 1, ensuring the ink adheres well to the printing surface and maintains lightfastness even in normal humidity conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Blue No. 1 and reduced isomaltulose are used in inkjet ink, then lightfastness is improved, but the ink becomes susceptible to humidity influence causing photodiscoloration and fading in normal to high humidity environments
Solution Approach 1:
The patent applies parameter changes by precisely controlling the concentration ratio of reduced isomaltulose to Blue No. 1 within 5.7 to 16.2 times, and optimizing the total content of reduced isomaltulose at 4.0 mass% or more and 15.0 mass% or less. This quantitative parameter optimization resolves the contradiction by achieving sufficient lightfastness while maintaining stability across different humidity conditions, preventing both photodiscoloration in low humidity and humidity-induced degradation in normal to high humidity environments.
Solution Approach 2:
The patent employs composite materials by formulating an inkjet ink system that combines Blue No. 1 (a tar pigment food dye) with reduced isomaltulose (a fixing agent) in specific proportions. This composite formulation creates a synergistic effect where the reduced isomaltulose protects the Blue No. 1 from photodiscoloration while the optimized composition ensures compatibility across varying humidity conditions, thus resolving the contradiction between lightfastness improvement and environmental adaptability.
2Loss of information
If food dyes are used to increase visibility of printed images, then visibility is improved, but photodiscoloration and fading occur due to light exposure
Solution Approach 1:
The patent applies the intermediary principle by introducing reduced isomaltulose as a protective mediator between Blue No. 1 and light exposure. The reduced isomaltulose acts as a fixing agent that stabilizes the Blue No. 1 pigment, preventing direct photodiscoloration while allowing the pigment to maintain its visibility function. This intermediary protection resolves the contradiction between achieving high visibility and preventing light-induced degradation.
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 formulation effectively suppresses photodiscoloration and fading, maintaining excellent lightfastness and visibility of printed images in both low and normal humidity environments, enhancing the durability of the inkjet ink.
Implementation Method 1
Some inkjet inks cause discoloration in which the color tone (hue) of the colorants has changed in printed characters, images, and the like due to the deterioration of the colorants or cause fading due to desaturation or the like of the colorants. For example, when the inkjet inks are insufficient in lightfastness, the colorants are affected by light and decompose (undergo photolysis) to cause discoloration and/or fading (photodiscoloration and/or photofading).
Data Source
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AI summary
This invention aims to provide an inkjet ink capable of sufficiently suppressing the photodiscoloration and/or photo fading of printed images and maintaining the lightfastness not only when the inkjet ink is stored and used in a low humidity environment (about 20%RH) but when the inkjet ink is stored and used in a normal humidity environment (about 50%RH), and a tablet (tablet printed matter) including printed parts printed with the inkjet ink. An inkjet ink according to this embodiment contains: Blue No. 1 as a food dye in the range of 0.1 mass% or more and 2.5 mass% or less based on the total mass of the inkjet ink; and reduced isomaltulose as a fixing agent in the range of 5.7 times or more and 16.2 times or less the mass of the Blue No. 1.