Thermal Transfer Sheet Friction Control for Seal-Type Printing
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Solution Overview
Problem
When using a thermal transfer sheet with a seal-type printing sheet, where the printing paper sheet has a pressure-sensitive adhesive layer on only a portion of the releasing substrate, wrinkles may occur in the print due to significant differences in dynamic friction coefficients between the colorant layer and the printing paper sheet, and the colorant layer and the releasing substrate.
Innovation Solution
A thermal transfer sheet and seal-type printing sheet combination where the dynamic friction coefficient difference between the colorant layer and the printing paper sheet with a pressure-sensitive adhesive layer, and the colorant layer and the releasing substrate is 1.0 or less, achieved by incorporating an organic filler in the colorant layer at 2% to 6% by mass with an average particle size of 1.0 to 2.5 µm, ensuring uniform friction and preventing wrinkles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a seal-type printing sheet with a pressure-sensitive adhesive layer on only a portion of the releasing substrate is used, then the printing process can be simplified and partial sealing is achieved, but wrinkles occur in the print due to significant differences in dynamic friction coefficients between the colorant layer and the printing paper sheet, and the colorant layer and the releasing substrate
Solution Approach 1:
The patent applies parameter changes by modifying the dynamic friction coefficient of the releasing substrate to be equal to or greater than that of the printing paper sheet. This is achieved by controlling the surface properties of the releasing substrate, ensuring uniform friction characteristics across different regions during the printing process, thereby preventing wrinkle formation while maintaining the simplified partial sealing structure
Solution Approach 2:
The patent applies homogeneity by ensuring that the dynamic friction coefficient is uniform across the releasing substrate and printing paper sheet. By making the friction characteristics homogeneous (μr ≥ μp), the patent eliminates the friction differential that causes wrinkles, allowing the thermal transfer sheet to move smoothly over both the adhesive layer and the releasing substrate without distortion
2Reliability
If the dynamic friction coefficient difference between the colorant layer and the printing paper sheet, and the colorant layer and the releasing substrate is large, then the thermal transfer sheet may stick to one surface more than the other, but this causes wrinkles and printing failures
Solution Approach 1:
The patent applies equipotentiality by equalizing the dynamic friction coefficients of the releasing substrate and printing paper sheet. By making μr ≥ μp, the patent creates a frictional equilibrium that prevents the thermal transfer sheet from preferentially sticking to one surface, thereby eliminating the potential difference that leads to wrinkle formation and printing inconsistencies
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 combination ensures uniform friction across the thermal transfer sheet and seal-type printing sheet, preventing wrinkles and enabling satisfactory printing by minimizing dynamic friction coefficient differences, thus enhancing printing quality.
Implementation Method 1
the difference between the dynamic friction coefficient between the colorant layer in the thermal transfer sheet and the printing paper sheet with a pressure-sensitive adhesive layer in the seal-type printing sheet and the dynamic friction coefficient between the colorant layer in the thermal transfer sheet and the releasing substrate in the seal-type printing sheet is 1.0 or less
Data Source
Figure 1~3
AI summary
Provided is a combination of a thermal transfer sheet and a seal-type printing sheet, the combination being capable of preventing occurrence of wrinkles in a print. In a combination of a thermal transfer sheet including a substrate and a colorant layer provided on one surface of the substrate and a seal-type printing sheet including a releasing substrate and a printing paper sheet with a pressure-sensitive adhesive layer provided on a portion of one surface of the releasing substrate, the difference between the dynamic friction coefficient between the colorant layer in the thermal transfer sheet and the printing paper sheet with a pressure-sensitive adhesive layer in the seal-type printing sheet and the dynamic friction coefficient between the colorant layer in the thermal transfer sheet and the releasing substrate in the seal-type printing sheet is 1.0 or less.