Azo Dye Ink Sheet for Heat-Sensitive Transfer Recording
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Solution Overview
Problem
Current heat-sensitive transfer recording materials lack dyes with desirable spectral characteristics for color reproduction, lightfastness, and stability under various conditions, and existing azo dyes are not effectively utilized in heat-sensitive transfer recording processes.
Innovation Solution
Development of an ink sheet containing a novel azo dye with specific heterocyclic groups and substituents, represented by formulas (1) and (2), which provides excellent spectral properties, high fastness, and improved color reproducibility, and is used in a heat-sensitive transfer recording method with an ink cartridge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional heat-movable dyes are used in heat-sensitive transfer recording materials, then the recording process can be performed, but the dyes fail to satisfy all requirements including spectral characteristics, lightfastness, heat fastness, and color reproduction range
Solution Approach 1:
The patent modifies the molecular structure of azo dyes by changing parameters such as introducing specific heterocyclic groups (pyrazole, triazole, tetrazole, oxadiazole, thiadiazole) at the 4-position, and adjusting substituents R1-R6 and electron-withdrawing groups. These parameter changes in the dye structure result in improved spectral characteristics, lightfastness, and heat fastness while maintaining suitability for heat-sensitive transfer recording processes.
Solution Approach 2:
The invention creates composite dye molecules combining azo groups with heterocyclic structures (such as 5-amino-3-phenylpyrazole, 5-amino-3-phenyl-1,2,4-triazole, etc.). This composite structure integrates the heat-movable properties of azo dyes with the enhanced stability and spectral characteristics of heterocyclic compounds, achieving both transferability and fastness requirements.
2Manufacturing precision
If existing azo dyes are used, then synthesis is possible, but they lack sharp absorption characteristics and high lightfastness required for excellent color reproduction
Solution Approach 1:
The patent achieves sharp absorption characteristics by modifying the chromophore structure through specific substituent patterns and electron-withdrawing groups. The lightfastness is improved by incorporating heterocyclic rings that stabilize the dye molecule against photo-degradation. These parameter changes in molecular structure simultaneously enhance both absorption sharpness and lightfastness.
Solution Approach 2:
The heterocyclic groups act as intermediary structures between the azo chromophore and the rest of the dye molecule, mediating the electronic properties to achieve sharp absorption while providing steric and electronic protection that enhances lightfastness.
3Productivity
If conventional dyes are used in heat-sensitive transfer recording, then image recording can be performed, but image bleeding occurs over time under high temperature and humidity conditions
Solution Approach 1:
The patent modifies the physical and chemical parameters of the dye molecules by introducing heterocyclic structures with specific substituent patterns. These changes enhance the thermal and humidity stability of the dye, preventing image bleeding while maintaining the heat-movable property necessary for transfer recording. The balanced molecular structure achieves both transferability and storage stability.
4Ease of operation
If standard heat-movable dyes are applied, then transfer recording is achieved, but retransfer occurs and color reproducibility is insufficient
Solution Approach 1:
The patent optimizes the molecular parameters of the dye by adjusting the heterocyclic group type, substituent positions, and electron-withdrawing group strength. These parameter changes fine-tune the dye's transfer characteristics and spectral properties, enabling easy transfer recording while achieving excellent color reproducibility through sharp absorption bands and stable color fastness.
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
The ink sheet achieves sharp absorption, high lightfastness, and minimal image bleeding or retransfer under high temperature and humidity conditions, enabling high-quality full-color image recording with excellent image storage properties.
Implementation Method 1
azo dye having excellent spectral properties, including sharp absorption
Implementation Method 2
heating a heat-sensitive transfer material comprising a heat-fusible ink layer formed on a base film (support) using a thermal head to melt the ink
Implementation Method 3
heating a heat-transfer material comprising a dye-providing layer containing a heat-movable dye formed on a base film to cause the dye to be heat-diffused and transferred
Data Source
AI summary
An ink sheet for heat-sensitive transfer recording material comprising an azo dye represented by the following formula (1):wherein R1, R2, R3 and R4 represent a hydrogen atom or substituent; and Het represents a heterocyclic group which may have substituents or a condensed ring.