Thermal Transfer Medium Undercoat Layer Design
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Solution Overview
Problem
Current thermal transfer recording media face challenges in achieving high transfer sensitivity during high-speed printing without abnormal transfer, especially when stored in high-temperature and high-humidity environments, due to issues like dye transfer and scumming.
Innovation Solution
A thermal transfer recording medium is developed with a heat-resistant sliding layer, an undercoat layer containing polyvinyl pyrrolidone and polyvinyl alcohol with a crystallinity degree of 15% or higher, and a dye layer with anthraquinone-based thermal transfer dye, along with specific resin ratios and surface roughness characteristics to prevent abnormal transfer and maintain high transfer sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the thickness of thermal transfer recording medium is decreased to increase transfer sensitivity, then transfer sensitivity is improved, but wrinkling and breaking occur due to heat and pressure
Solution Approach 1:
The patent uses a composite structure with a substrate, undercoat layer containing polyvinyl pyrrolidone and polyvinyl alcohol, and dye layer. This multi-layer composite design allows the thin structure to maintain sufficient mechanical strength while achieving high transfer sensitivity, preventing wrinkling and breaking during printing.
2Manufacturing precision
If the amount of dye in dye layer is increased to improve print density and transfer sensitivity, then transfer sensitivity is improved, but dye is transferred to heat-resistant sliding layer causing scumming
Solution Approach 1:
The undercoat layer containing polyvinyl pyrrolidone and polyvinyl alcohol acts as an intermediary barrier between the dye layer and heat-resistant sliding layer. This intermediate layer prevents dye from transferring to the sliding layer during winding and storage, eliminating scumming while allowing high dye content for improved print density.
Solution Approach 2:
The patent changes the chemical composition parameters of the undercoat layer by specifying polyvinyl pyrrolidone and polyvinyl alcohol with specific crystallinity degree (15% or higher). This parameter change creates optimal adhesion and barrier properties that prevent dye transfer while maintaining print quality.
3Manufacturing precision
If energy during image forming is increased to improve transfer sensitivity, then transfer sensitivity is improved, but power consumption increases and thermal head service life decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the undercoat layer (polyvinyl pyrrolidone and polyvinyl alcohol with crystallinity degree of 15% or higher) to optimize thermal transfer efficiency. This allows high transfer sensitivity to be achieved with reduced energy input, lowering power consumption and thermal head service life degradation.
4Reliability
If release agent is added to dye layer or transfer medium to prevent abnormal transfer, then abnormal transfer is prevented, but bleeding or scumming occurs on image
Solution Approach 1:
The undercoat layer serves as an intermediary that provides abnormal transfer prevention without requiring release agents in the dye layer. The polyvinyl pyrrolidone and polyvinyl alcohol combination creates optimal adhesion control, preventing dye from adhering to unwanted surfaces while maintaining image quality without bleeding or scumming.
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 solution enables high transfer sensitivity and high-density images during high-speed printing while preventing abnormal transfer even after storage in high-temperature and high-humidity conditions, without increasing the dye amount in the dye layer.
Implementation Method 1
the undercoat layer contains, as major components, polyvinyl pyrrolidone and polyvinyl alcohol having a crystallinity degree of 15% or more
Implementation Method 2
a thermal transfer layer is formed on one surface of a substrate, and a heat-resistant sliding layer (so-called, backcoat layer) is formed on the other surface of the substrate. The thermal transfer layer described herein is a layer containing ink, in which this ink is sublimated (sublimation thermal transfer type) or fused (fusion thermal transfer type) by heat generated in a thermal head
Data Source
AI summary
There is provided a thermal transfer recording medium capable of obtaining high transfer sensitivity during high-speed printing, that is, decreasing the amount of a dye used in a dye layer; and preventing abnormal transfer during printing even after storage in a high-temperature and high-humidity environment. The thermal transfer recording medium (1) contains: a heat-resistant sliding layer (40) that is formed on one surface of a substrate (10); and an undercoat layer (20) and a dye layer (30) that are sequentially laminated on the other surface of the substrate (10), in which the undercoat layer (20) contains, as major components, a polyvinyl pyrrolidone and a polyvinyl alcohol having a crystallinity degree of 15% or higher, and the dye layer (30) contains an anthraquinone-based thermal transfer dye.