Thermal Head Double-Layer Protective Layer Anti-Sticking Design
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Solution Overview
Problem
Conventional thermal heads experience sticking issues during printing due to the adhesive force between thermal recording paper and the protective layer, which is exacerbated by the softening of components under heat, leading to irregular transfer and potential print failures, and reducing frictional resistance alone is insufficient to prevent sticking without compromising heat transfer and printing quality.
Innovation Solution
A thermal head with a double-layer protective structure, where the first protective layer is made of amorphous glass and the second layer is conductive crystallized glass, with specific thickness and baking temperature conditions to enhance adhesion and prevent sticking while maintaining heat transfer efficiency, and the manufacturing method involves forming the first layer by baking amorphous glass and the second layer by baking crystallized glass with a conductive component at a controlled temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the protective layer is made of amorphous glass to reduce frictional resistance and prevent sticking, then the smoothness of the surface is improved, but the wear resistance deteriorates
Solution Approach 1:
The protective layer is divided into two separate layers: a first protective layer made of amorphous glass that contacts the recording paper to provide smoothness and prevent sticking, and a second protective layer made of crystallized glass that provides wear resistance. This segmentation allows each layer to independently fulfill its specific function without compromise.
Solution Approach 2:
The protective layer structure combines two different glass materials with complementary properties: amorphous glass for low friction and smooth surface, and crystallized glass for high wear resistance. This composite structure achieves both smoothness and durability that neither material could provide alone.
2Strength
If a double-layer protective structure with crystallized glass is used to enhance wear resistance, then the durability is improved, but the sticking problem persists due to insufficient friction reduction
Solution Approach 1:
The protective layer is segmented into two functional layers with distinct roles: the first layer (amorphous glass)专门负责 reducing friction and preventing sticking through its smooth surface, while the second layer (crystallized glass) provides structural support and wear resistance. This clear functional division resolves the contradiction between durability and anti-sticking performance.
Solution Approach 2:
Different regions of the protective layer structure are assigned different material properties tailored to local requirements: the outer surface layer uses amorphous glass with low friction characteristics where contact with recording paper occurs, while the inner layer uses crystallized glass with high strength where mechanical support is needed.
3Ease of operation
If the pressing force is reduced to prevent sticking, then the adhesive force between recording paper and protective layer is decreased, but the heat transfer efficiency deteriorates
Solution Approach 1:
The patent replaces the mechanical approach of reducing pressing force to prevent sticking with a material science solution: using amorphous glass with inherently low friction coefficients. This allows maintaining adequate pressing force for heat transfer while the material properties of amorphous glass prevent excessive adhesion, enabling easy paper removal without compromising printing quality.
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 double-layer structure effectively prevents sticking by ensuring easy removal of thermal recording paper and maintaining printing quality without degrading heat transfer, while the manufacturing method ensures durability and productivity by controlling the adhesion and porosity of the protective layers.
Implementation Method 1
the first protective layer is formed by baking amorphous glass
Implementation Method 2
the second layer by baking crystallized glass with a conductive component at a controlled temperature
Implementation Method 3
the second layer by baking crystallized glass
Implementation Method 4
the heat generated at the heat-producing resistor 95 is transferred to the thermal recording paper S via the protective layer 96
Data Source
AI summary
A thermal head (A) according to the present invention includes a substrate (1) on which a heat-producing resistor (5), a common electrode (3) and individual electrodes (4) for energizing the heat-producing resistor (5), and a protective layer (6) having a double-layer structure and formed on the heat-producing resistor (5) to cover at least the heat-producing resistor are provided. A second protective layer (6B) constituting the upper layer of the protective layer (6) is conductive, and a first protective layer (6A) constituting the lower layer of the protective layer (6) has thickness (t1) which is not less than three times the thickness (t2) of the second protective layer (6B).