Thermal Head Protective Layer Skewness
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Solution Overview
Problem
Conventional thermal heads experience sticking issues due to the recording medium adhering to parts of the protective layer without recesses, despite efforts to improve slip, leading to suboptimal printing performance and noise.
Innovation Solution
The thermal head incorporates a protective layer with a skewness greater than 0, featuring a surface with more valley parts than crest parts, reducing the contact area with the recording medium and enhancing slip, while maintaining abrasion resistance, thereby preventing sticking and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the protective layer has recesses formed to improve slip, then the recording medium becomes harder to stick to the protective layer, but the recording medium may still stick to parts without recesses, causing sticking issues to persist
Solution Approach 1:
The invention changes the surface roughness parameters of the protective layer, specifically setting the arithmetic mean roughness Ra to 0.01 μm or less and the skewness Rsk to -0.5 or less. This parameter optimization ensures that the entire surface provides consistent slip properties, preventing the recording medium from sticking to any portions of the protective layer.
2Ease of operation
If the protective layer surface is made smoother to reduce sticking, then slip improves, but the abrasion resistance of the protective layer may be compromised
Solution Approach 1:
The invention optimizes multiple surface parameters simultaneously: Ra ≤ 0.01 μm for smoothness, Rsk ≤ -0.5 for valley distribution, and maintains kurtosis Rku ≥ 3.0. This combination ensures both excellent slip properties and sufficient abrasion resistance by controlling the distribution and depth of surface valleys without compromising overall surface integrity.
Solution Approach 2:
The protective layer is formed as a composite structure with specific material composition and surface treatment that achieves both low roughness for slip and sufficient hardness for abrasion resistance. The layered structure allows the surface to be optimized for slip while maintaining bulk properties for durability.
3Ease of manufacture
If conventional protective layer structures are used, then manufacturing is simpler, but sticking occurs and printing quality deteriorates
Solution Approach 1:
The invention specifies precise surface parameter ranges (Ra ≤ 0.01 μm, Rsk ≤ -0.5, Rku ≥ 3.0) that can be achieved through conventional polishing and coating techniques, ensuring that the improved printing quality does not come at the cost of manufacturing complexity. These parameters represent an optimized target within achievable manufacturing capabilities.
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 configuration effectively reduces sticking and noise, allowing for improved printing quality and increased abrasion resistance, enabling fine printing and efficient thermal transfer without wrinkles in the ink ribbon.
Implementation Method 1
a skewness Rsk of the protective layer is larger than 0
Implementation Method 2
heat-generating portions positioned on the substrate, electrodes which are positioned on the substrate and are connected to the heat-generating portions
Data Source
AI summary
A thermal head of the present disclosure includes a substrate, a heat-generating portion, electrodes, and a protective layer. The heat-generating portion is located on the substrate. The electrodes are located on the substrate and are connected to the heat-generating portion. The protective layer covers the heat-generating portion and parts of the electrodes. A skewness Rsk of the protective layer is larger than 0. Further, A thermal head of the present disclosure includes a substrate, a heat-generating portion, electrodes, and a protective layer. The heat-generating portion is located on the substrate. The electrodes are located on the substrate and are connected to the heat-generating portion. The protective layer covers the heat-generating portion and parts of the electrodes. A kurtosis Rku of the protective layer is larger than 3.