Thermal Head Protective Layer Surface Relief
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Solution Overview
Problem
Conventional thermal heads face issues with low abrasion resistance and sticking of the recording medium due to the concentration of external forces on convex portions of the protective layer, which reduces the effectiveness of the printing process.
Innovation Solution
The thermal head incorporates a protective layer with a surface relief structure, characterized by specific roughness and kurtosis values, to maintain slip while enhancing abrasion resistance, thereby reducing friction and sticking, and improving thermal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the protective layer contact surface is formed with surface relief to make the contact area smaller, then slip is improved, but the recording medium becomes harder to stick to the protective layer and sticking occurs
Solution Approach 1:
The protective layer contact surface is formed with surface relief having specific roughness and kurtosis values to create local variations in contact characteristics. The surface relief structure provides both slip and sticking properties through controlled local geometry, allowing the recording medium to stick reliably while maintaining ease of operation.
2Ease of operation
If the contact surface of the protective layer is formed with surface relief, then slip is improved, but external force is concentrated to the convex portions reducing abrasion resistance
Solution Approach 1:
The surface relief structure parameters (roughness and kurtosis values) are specifically controlled to optimize both slip and abrasion resistance. By adjusting these parameters, the contact surface maintains slip while distributing external force more evenly, preventing concentration on convex portions and improving abrasion resistance.
3Strength
If the protective layer is made with specific surface relief characteristics, then abrasion resistance is improved, but friction and sticking increase
Solution Approach 1:
The surface relief parameters (roughness and kurtosis) are precisely controlled to achieve the optimal balance between abrasion resistance and friction. The specific parameter values ensure that the protective layer maintains low friction and sticking while providing high abrasion resistance through the controlled surface geometry.
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 improved thermal head achieves enhanced abrasion resistance and reduced sticking, resulting in quieter operation, finer printing, and reduced wrinkle formation in the ink ribbon, leading to a more efficient thermal printing process.
Implementation Method 1
heat-generating portions (9) which generate heat in response to application of voltage from an external portion
Implementation Method 2
the contact surface of the protective layer (25) is formed with surface relief... the arithmetic average roughness Ra of the protective layer (25) is 67.7 μm or less... the kurtosis Rku of the protective layer (25) is smaller than 3
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A thermal head x1 of the present disclosure includes a substrate 7, a heat-generating portion 9, electrodes 17 and 19, and a protective layer 25. The heat-generating portion 9 is located on the substrate 7. The electrodes 17 and 19 are located on the substrate 7 and are connected to the heat-generating portion 9. The protective layer 25 covers the heat-generating portion 9 and parts of the electrodes 17 and 19. Further, a kurtosis Rku of the protective layer 25 is smaller than 3. A thermal head x1 of the present disclosure includes a substrate 7, a heat-generating portion 9, electrodes 17 and 19, and a protective layer 25. The heat-generating portion 9 is located on the substrate 7. The electrodes 17 and 19 are located on the substrate 7 and are connected to the heat-generating portion 9. The protective layer 25 covers the heat-generating portion 9 and parts of the electrodes 17 and 19. Further, a skewness Rsk of the protective layer 25 is smaller than 0.