Thermal Transfer Sheet With Decolorizable Dye For Image Alteration
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Solution Overview
Problem
Existing thermal transfer methods lack the ability to effectively eliminate or change printed images and their coloring, limiting the added value and versatility of printed products.
Innovation Solution
A thermal transfer sheet incorporating decolorizable dyes, such as those represented by structural formulas (1), (2), (3), and (4), which change color or fade when exposed to light, allowing for the creation of printed articles with images that can be intentionally altered or removed, including a combination of decolorizable and light-fast dyes for controlled color shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional thermal transfer methods are used, then high-quality printed images with excellent transparency and gray scale can be obtained, but the images cannot be eliminated or changed once printed
Solution Approach 1:
The patent applies dynamics by making the printed image changeable rather than static. The dye layer is designed to respond dynamically to light exposure, transitioning from a colored state to a decolorized state. This allows the same printed article to exhibit different visual states (with image/without image) based on external conditions, thereby achieving both image stability during normal use and the ability to eliminate/change images when needed.
Solution Approach 2:
The patent directly applies color changes by using dyes that undergo decolorization upon light irradiation. The dye layer is specifically selected to have a color difference ΔE*ab of 10 or less before and after irradiation, ensuring controlled color transformation. This enables the printed image to be eliminated or changed by exposing it to light, while maintaining high-quality printing characteristics during normal conditions.
2Adaptability or versatility
If dyes with high light fastness are used, then image stability is maintained, but the ability to eliminate or change images is lost
Solution Approach 1:
The patent applies parameter changes by carefully selecting dyes with specific color difference parameters (ΔE*ab ≤ 10) that balance light fastness and decolorizability. By controlling the chemical structure and properties of the dye molecules, the patent achieves an optimal parameter range where the dye maintains sufficient stability for high-quality printing but can still undergo controlled decolorization when exposed to light, enabling image elimination or color change.
3Adaptability or versatility
If conventional dyes are used, then excellent gray scale and transparency are achieved, but the printed image cannot be eliminated
Solution Approach 1:
The patent applies color changes by using dyes that undergo controlled decolorization upon light irradiation. The dye layer is specifically selected to maintain excellent gray scale and transparency characteristics during normal conditions while enabling complete or partial image elimination when exposed to light. This dual functionality is achieved by selecting dyes with appropriate molecular structures that allow reversible or irreversible color transformation.
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
Enables the elimination or alteration of printed images and their coloring, providing enhanced product value and functionality, such as authenticity verification through UV exposure, by ensuring the images disappear or change as desired.
Implementation Method 1
the decolorizable dye has a color difference ΔE*ab between a color A and a color B of 10 or less, where the color A is a color of a transfer-receiving body before the decolorizable dye is transferred to the transfer-receiving body, the color B is a color of a portion of the transfer-receiving body with the decolorizable dye having been transferred thereto, and the color of the portion is a color after the portion is irradiated by a xenon lamp at an irradiation intensity of 1.2 (W/m2) for 50 hours
Implementation Method 2
heat is applied thereto with a thermal head from a side adjacent to a back surface of the thermal transfer sheet, to transfer the dye of the dye layer onto the receiving layer
Data Source
AI summary
A thermal transfer sheet includes a dye layer disposed on a first surface of a substrate film. The dye layer includes a decolorizable dye. The decolorizable dye has a color difference ΔE*ab between a color A and a color B of 10 or less, where the color A is a color of a transfer-receiving body before the decolorizable dye is transferred to the transfer-receiving body, the color B is a color of a portion of the transfer-receiving body with the decolorizable dye having been transferred thereto, and the color of the portion is a color after the portion is irradiated by a xenon lamp at an irradiation intensity of 1.2 (W/m2) for 50 hours, the portion having a reflection density of 0.5 or greater before being irradiated by the xenon lamp.