Energy-resistant, corrosion-resistant, wear-resistant thermal printhead heating substrate

Abstract

The heat generating substrate for a thermal print head is provided with an insulating substrate (1) and is energy-resistant, corrosion-resistant, wear-resistant, and has a base glaze layer (2) made of an amorphous glass material provided on the surface of the insulating substrate (1), a common electrode and individual electrodes (3) are provided on the surface of the base glaze layer (2), a heat generating resistor (4) is disposed between the common electrode and the individual electrode (3), and a protective layer (5) is provided on the surfaces of the heat generating resistor (4), the common electrode, and the individual electrode (3). The protective layer (5) is a second protective layer (5) that is provided on the surface of the heat generating resistor (4). The thermal printhead heating substrate has a first protective layer (5a), the first protective layer (5a) being a glass glaze layer having a transition temperature range of 600 to 725°C or a glass glaze layer having a softening temperature range of 700 to 870°C. The thermal printhead heating substrate has the features of being simple to produce and low cost, greatly reducing the damage to the heating resistor caused by high printing energy, improving the corrosion resistance of the printhead in high temperature and high humidity environments and the wear resistance in poor environments, and significantly improving the reliability of the product.

Description

[Technical field]

[0001] The embodiments of the present application relate to the technical field of thermal printhead manufacturing, for example, to a thermal printhead heating substrate that can significantly improve the energy resistance characteristics of a heating resistor in a thermal printhead and effectively improve the wear resistance and corrosion resistance of the heating substrate. [Background technology]

[0002] A thermal printhead in the related art comprises an insulating substrate, a base glaze layer is provided on the surface of the insulating substrate, a common electrode and individual electrodes are provided on the surfaces of the insulating substrate and the base glaze layer, a heating resistor is disposed between the two electrodes, one end of the common electrode is connected to the heating resistor and the other end is used for connection to a power source, one end of the individual electrode is connected to the heating resistor and the other end is connected to a bonding pad, a glass glaze protective layer is provided on the surfaces of the heating resistor, the individual electrode and the common electrode, and a ceramic wear-resistant layer formed in a thin film manner is further provided on the surface of the glass glaze protective layer.

[0003] Thermal printheads in the related art have low sensitivity to the printing medium and the quality of the printing medium is poor. The heating resistor of the thermal printhead requires more Joule heat to cause the printing medium to color. When the temperature exceeds the internal glass softening point or transition point temperature of the heating resistor due to the increased Joule heat, the resistance value of the heating resistor increases and the resistor becomes more susceptible to destruction. In high temperature and high humidity environments, the metal electrodes are corroded and broken due to the insufficient corrosion resistance of the protective layer. In addition, the quality of the printing medium is poor, and in outdoor environments, the wear resistance of the protective layer is insufficient, so the resistor or metal electrodes are damaged by media or foreign particles, either of which causes damage to the product. Summary of the Invention [Problem to be solved by the invention]

[0004] The following is a summary of the subject matter discussed in detail in this paper, which is not intended to limit the scope of protection of the claims.

[0005] The embodiment of the present application provides a thermal printhead heating substrate which can significantly improve the energy resistance characteristics of the heating resistor in the thermal printhead and effectively improve the wear resistance and corrosion resistance of the heating substrate. [Means for solving the problem]

[0006] The embodiment of the present application is achieved by the following measures.

[0007] an insulating substrate made of an amorphous glass material and provided with a base glaze layer on the surface of which a common electrode and individual electrodes are provided; a heating resistor is disposed between the common electrode and the individual electrodes; one end of the common electrode is connected to the heating resistor and the other end is used for connection to a power source; one end of the individual electrode is connected to the heating resistor and the other end is connected to a bonding pad; and a protective layer is provided on the surfaces of the heating resistor, the individual electrode and the common electrode, the protective layer including a first protective layer which covers the surface of the heating resistor and is a glass glaze layer having a transition point temperature range of 600 to 725°C or a glass glaze layer having a softening point temperature range of 700 to 870°C; A thermal printhead heating substrate that is energy-resistant, corrosion-resistant, and abrasion-resistant.

[0008] The components in the first protective layer described in the examples of the present application, measured in the oxide state, are as follows: SiO2 content is 49.4 mol% to 56.8 mol%, Al2O3 content is 13.7 mol% to 26.7 mol%, CaO content is 3.5 mol% to 13.8 mol%, BaO content is 1.5 mol% to 5.9 mol%, PbO content is 4.8 mol% to 17.7 mol%, and ZrO2 content is 1.2 mol% to 5.0 mol%.

[0009] Among the protective layers described in the examples of the present application, a second protective layer employing an insulating glass glaze layer or a conductive glass glaze layer is compounded on the upper side of a first protective layer, and the transition point or softening point of the second protective layer is lower than the transition point or softening point of the first protective layer. When the second protective layer is a conductive glass glaze layer, the resistivity range is 0.01 Ω·m to 10 kΩ·m.

[0010] The protective layer described in the embodiment of the present application further includes a thin-film ceramic wear-resistant protective layer located on the glass glaze layer, the thin-film ceramic wear-resistant protective layer being made of one of silicon carbide, sialon, and silicon nitride, or a composite thin-film ceramic layer made of any two of silicon carbide, sialon, and silicon nitride, the thin-film ceramic wear-resistant layer being used for contact with the external environment and the printing medium, and improving the wear resistance of the product. Effect of the Invention

[0011] The beneficial effects of the embodiments of the present application are as follows: the insulating glass glaze with a high transition point (greater than 600°C) or high softening point (greater than 700°C) is adopted as the first protective layer, which partially diffuses into the heating resistor during sintering, and increases the transition point or softening point of the glass composition inside the heating resistor, improving the energy resistance properties of the heating resistor and reducing the increase in the resistance value of the heating resistor when printing with high energy; the insulating glass glaze with a high transition point or high softening point is prepared by high temperature melting and needs to be sintered at high temperature, has good chemical stability, and significantly enhances the corrosion resistance of the product; the thin-film ceramic wear-resistant protective layer formed by a thin-film process on the surface of the glass glaze protective layer further enhances the wear resistance; the heating substrate for thermal printhead of the present application has the characteristics of simple production method and low cost, and can greatly reduce the destruction of the heating resistor caused by high printing energy, and can improve the corrosion resistance ability of the printhead in high temperature and high humidity environment and the wear resistance in poor environment, thereby significantly improving the reliability of the product.

[0012] Other aspects may be understood upon reading and understanding the drawings and detailed description. [Brief description of the drawings]

[0013] The drawings are intended to provide a further understanding of the technical solution of the present document, constitute a part of the specification, and are used to interpret the technical solution of the present document together with the embodiments of the present application, and are not intended to limit the technical solution of the present document.

[0014] [Figure 1] FIG. 1 is a structural schematic diagram of Example 1 of the present application. [Diagram 2] FIG. 2 is a structural schematic diagram of Example 2 of the present application. [Diagram 3] FIG. 2 is a structural schematic diagram of Example 3 of the present application. [Explanation of symbols]

[0015] 1 insulating substrate, 2 base glaze layer, 3 common electrode and individual electrode, 4 heating resistor, 5 protective layer, 5a first protective layer (insulating glass glaze layer with high transition point or high softening point), 5b second protective layer (insulating glass glaze layer with low transition point or low softening point), 5c third protective layer (insulating glass glaze layer with low transition point or low softening point), 5d thin film ceramic wear-resistant protective layer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The present application will now be further described with reference to the drawings and examples.

[0017] In view of the deficiencies and shortcomings of the prior art, the present application provides an energy-resistant, corrosion-resistant and wear-resistant heating substrate for a thermal printhead, which comprises an insulating substrate, a base glaze layer made of an amorphous glass material is provided on a surface portion of the insulating substrate, a common electrode and individual electrodes are provided on the surface of the base glaze layer, a heating resistor is disposed between the common electrode and the individual electrode, one end of the common electrode is connected to the heating resistor and the other end is used for connection to a power source, one end of the individual electrode is connected to the heating resistor and the other end is connected to a bonding pad, and the heating resistor, the individual electrode and the common electrode are electrically connected to each other. The electrode surface is provided with a composite protective layer consisting of a glass glaze layer and a ceramic wear-resistant layer formed by a thin film process, and the glass glaze protective layer has at least a first protective layer 5a consisting of an insulating glass glaze with a high transition point or high softening point, and the transition point or softening point of the glass composition constituting the first protective layer 5a is higher than the transition point or softening point temperature of the glass composition in the heating resistor, and the first protective layer 5a is subsequently called an insulating glass glaze protective layer with a high transition point or high softening point, and its transition point is 600-725°C, or its softening point is 700-870°C.

[0018] Preferably, the insulating glass glaze having a transition temperature of 600 to 725°C or a softening point of 700 to 870°C has, when its composition is measured in an oxide state, a SiO2 content of 49.4 mol% to 56.8 mol%, an Al2O3 content of 13.7 mol% to 26.7 mol%, a CaO content of 3.5 mol% to 13.8 mol%, a BaO content of 1.5 mol% to 5.9 mol%, a PbO content of 4.8 mol% to 17.7 mol%, and a ZrO2 content of 1.2 mol% to 5.0 mol%.

[0019] Preferably, the insulating glass glaze having a transition temperature of 600 to 725°C or a softening point temperature of 700 to 870°C has, when its composition is measured in an oxide state, a SiO2 content of 49.4 mol% to 54.5 mol%, an Al2O3 content of 17.7 mol% to 26.7 mol%, a CaO content of 3.5 mol% to 10.5 mol%, a BaO content of 1.5 mol% to 5.0 mol%, a PbO content of 8.5 mol% to 17.7 mol%, and a ZrO2 content of 1.2 mol% to 3.8 mol%.

[0020] Preferably, the insulating glass glaze having a transition temperature of 600 to 725°C or a softening point temperature of 700 to 870°C has, when its composition is measured in an oxide state, a SiO2 content of 52.0 mol% to 54.5 mol%, an Al2O3 content of 17.7 mol% to 22.5 mol%, a CaO content of 6.5 mol% to 10.5 mol%, a BaO content of 2.5 mol% to 5.0 mol%, a PbO content of 8.5 mol% to 13.5 mol%, and a ZrO2 content of 2.5 mol% to 3.8 mol%.

[0021] Preferably, the first protective layer may be an insulating glass glaze protective layer independently, or may form a glass glaze protective layer together with another glass glaze protective layer, the other glass glaze protective layer may be an insulating glass glaze or a conductive glass glaze, and the resistivity of the conductive glass glaze protective layer is 0.01 Ω·m to 10 kΩ·m.

[0022] Preferably, the transition point or softening point of the insulating glass glaze protective layer other than the first protective layer is lower than the transition point or softening point of the composition of the first protective layer, and is hereinafter referred to as a low transition point or low softening point insulating glass glaze protective layer.

[0023] Preferably, a thin-film ceramic wear-resistant protective layer 5d formed by a thin-film process is provided on the surface of the protective layer, and the thin-film ceramic wear-resistant protective layer 5d is made of one of silicon carbide, sialon, and silicon nitride, or is a composite thin-film ceramic layer made of any two of silicon carbide, sialon, and silicon nitride.

[0024] The composition of the insulating glass glaze protective layer according to the present application does not exist in the form of various single oxides, but usually exists in the form of complex oxides or compounds. In the present application, the components of the glass composition are generally expressed in terms of single oxides. For example, the insulating glass glaze may contain PbSiO3, etc., and the single oxides are expressed as PbO and SiO2, respectively.

[0025] Hereinafter, an energy-resistant thermal printhead heating substrate and its manufacturing method are provided, and a comparative example is also provided.

[0026] Here, the meanings of the parameters mentioned in the following description are as follows:

[0027] The fired appearance is evaluated by (1) measuring the surface roughness with a surface roughness tester, taking 10 samples for each glass glaze composition, measuring them, and calculating the average value, and (2) observing the surface condition of the glass glaze, such as surface leveling and defects, with a stereomicroscope.

[0028] Tg (glass transition temperature) and Ts (glass softening temperature) are measured by using differential thermal analysis (DTA) to take 10 samples of glass glaze of each composition and calculate the average value.

[0029] STOL (energy resistance test) applies 1.5 to 2 times the rated heat energy to a resistor, measures the rate of change in the resistance value of the heating resistor, samples and measures 192 heating resistors for each composition of glass glaze protective layer, and calculates the average value.

[0030] The corrosion resistance test is carried out under fixed temperature and humidity conditions, with the thermal print head in an actual operating state, while being energized and waiting, and the time until corrosion damage occurs in the insulating glass glaze protective layer is measured.

[0031] First, various oxides are mixed in a stoichiometric ratio and melted at high temperature to prepare frits, and then samples are taken to measure Tg and Ts. An appropriate amount of the frit is taken and crushed to prepare glass glaze powder, and then filler, organic solvent and resin are added to prepare a high transition point or high softening point insulating glass glaze protective layer slurry after mixing.

[0032] Calculated on an oxide basis, the contents of various components of the high transition or softening point insulating glass glaze composition are as shown in Table 1.

[0033] Table 1 JPEG0007639172000001.jpg71170

[0034] Next, the insulating glass glaze protective layer slurry prepared above was printed on the surface of the substrate on which the electrodes and ruthenium dioxide heating resistor had been prepared, and sintered to prepare a first insulating glass glaze protective layer. A thermal printhead substrate was then produced, and a power resistance characteristic test and a corrosion resistance characteristic test were performed. The results of each item are recorded in Table 2.

[0035] Table 2 JPEG0007639172000002.jpg68170

[0036] In addition, the insulating glass glaze protective layer slurries of samples 3 to 7 with STOL>-3% are selected, and printed on the surface of the substrate on which the electrodes and ruthenium dioxide heating resistors have been prepared, and sintered to prepare a first glass glaze protective layer sample with a high transition point or softening point. Then, a silicon carbide wear-resistant layer is formed on the surface of some of the samples by a thin film process to prepare a thermal printhead substrate. The second glass glaze protective layer slurry is printed on the surface of some of the samples, and sintered to prepare a second glass glaze protective layer. Then, a silicon carbide wear-resistant layer is formed on the surface of the second glass glaze protective layer by a thin film process to prepare a thermal printhead substrate. Furthermore, energy resistance property tests and corrosion resistance property tests are performed, and the insulating glass protective layer with a high transition point or high softening point is used to combine with other glass glaze protective layers. The energy resistance and corrosion resistance performance of the thermal printhead of the present application are obviously improved compared to the prior art, and the results of each item are recorded in Table 3.

[0037] Table 3 JPEG0007639172000003.jpg162170

[0038] Example 1 As shown in FIG. 1, the energy-resistant and corrosion-resistant heating substrate for a thermal printhead according to this embodiment includes an insulating substrate 1, a base glaze layer 2 made of an amorphous glass material is provided on the surface of the insulating substrate 1, a common electrode and individual electrodes 3 are provided on the surface of the base glaze layer 2, a heating resistor 4 is disposed between the common electrode and the individual electrodes 3 along the main printing direction, and as a heating element that generates Joule heat, one end of the common electrode is connected to the heating resistor 4 along the sub-printing direction and the other end is used for connection to a power source, and one end of the individual electrode is connected to the heating resistor 4 along the sub-printing direction. In order to protect the heating substrate, a protective layer 5 is coated on the surfaces of the heating resistor 4, the common electrode and the individual electrodes 3. The protective layer 5 is made of a first protective layer made of an insulating glass glaze 5a with a transition point of 600°C and a softening point of 700°C, and a silicon carbide ceramic protective layer formed by a thin film process, as shown in Table 3.

[0039] The high softening point or transition point glass glaze 5a partially diffuses into the heating resistor during sintering, increasing the glass softening point temperature of the heating resistor and enhancing the power resistance of the heating resistor. The high softening point or transition point insulating glass glaze 5a has a certain fluidity during sintering and has good surface smoothness after sintering, with very few defects on the surface of 5a, improving the corrosion resistance of the product. The silicon carbide ceramic layer enhances the wear resistance of the thermal printhead substrate, resulting in a thermal printhead substrate that is energy-resistant, corrosion-resistant and wear-resistant.

[0040] Example 2 As shown in Fig. 2, the energy-resistant and corrosion-resistant heating substrate for a thermal printhead according to this embodiment includes an insulating substrate 1, and a base glaze layer 2 made of an amorphous glass material is provided on the surface of the insulating substrate 1. A common electrode and individual electrodes 3 are provided on the surface of the base glaze layer 2, and a heating resistor 4 is disposed between the common electrode and the individual electrodes 3 along the main printing direction, and as a heating element that generates Joule heat, one end of the common electrode is connected to the heating resistor 4 along the sub-printing direction, and the other end is used for connection to a power source, and one end of the individual electrode is connected to the heating resistor 4 along the sub-printing direction. In order to protect the heating substrate, a protective layer 5 is coated on the surfaces of the heating resistor 4, the common electrode, and the individual electrodes 3. The protective layer 5 is selected from sample 5 as shown in Table 3, and is composed of a first protective layer made of an insulating glass glaze 5a with a transition point of 683°C and a softening point of 812°C, a second protective layer made of an insulating glass glaze 5b, and a silicon carbide ceramic protective layer formed by a thin film process. The high softening point glass glaze 5a partially diffuses into the heating resistor during sintering, increasing the glass softening point temperature of the heating resistor and enhancing the energy resistance of the heating resistor. The glass protective layer 5b has good fluidity during sintering, and the insulating glass glaze 5 has good surface smoothness after sintering, improving the surface density of the high softening point glass glaze 5a and further improving the corrosion resistance of the product. The silicon carbide ceramic layer enhances the wear resistance of the thermal printhead substrate, resulting in a thermal printhead substrate that is energy-resistant, corrosion-resistant and wear-resistant.

[0041] Example 3 As shown in Fig. 3, the energy-resistant and corrosion-resistant heating substrate for a thermal printhead according to this embodiment includes an insulating substrate 1, and a base glaze layer 2 made of an amorphous glass material is provided on the surface of the insulating substrate 1. A common electrode and individual electrodes 3 are provided on the surface of the base glaze layer 2, and a heating resistor 4 is disposed between the common electrode and the individual electrodes 3 along the main printing direction, and as a heating element that generates Joule heat, one end of the common electrode is connected to the heating resistor 4 along the sub-printing direction and the other end is used for connection to a power source, and one end of the individual electrode is connected to the heating resistor 4 along the sub-printing direction. In order to protect the heating substrate, a protective layer 5 is coated on the surfaces of the heating resistor 4, the common electrode and the individual electrodes 3. The protective layer 5 is made of a first protective layer made of an insulating glass glaze 5a with a transition point of 683°C and a softening point of 812°C, a second protective layer made of a conductive glass glaze 5b with a resistivity of 10 Ω·m, and a silicon carbide ceramic protective layer formed by a thin film process, as shown in Table 3. In this example, the high softening point glass glaze 5a partially diffuses into the heating resistor during sintering, increasing the glass softening point temperature of the heating resistor and enhancing the energy resistance of the heating resistor. The conductive glass glaze protective layer 5b reduces the potential of the substrate surface, reducing the electrochemical corrosion of the wear-resistant protective layer at high temperature and humidity, thereby reducing the corrosive effect on the electrodes in high temperature and humidity environments and improving the corrosion resistance of the product. The silicon carbide ceramic layer enhances the wear resistance of the thermal printhead substrate, resulting in a thermal printhead substrate that is energy-resistant, corrosion-resistant and wear-resistant.

[0042] The present application may also adopt other combination methods, for example, a glass glaze with a high softening point or high transition point is used as the first protective layer, a glass glaze with a low softening point or low transition point is used as the second protective layer and the third protective layer, and a silicon carbide ceramic protective layer formed by a thin film process is used to jointly form a protective layer, thereby obtaining a thermal printhead substrate that is energy-resistant, corrosion-resistant and wear-resistant.

Claims

1. An insulating substrate made of an amorphous glass material is provided on a surface portion, the insulating substrate having a base glaze layer on the surface of which a common electrode and individual electrodes are provided; the heating resistor is disposed between a common electrode and an individual electrode, one end of the common electrode is connected to the heating resistor and the other end is used for connection to a power source, one end of the individual electrode is connected to the heating resistor and the other end is connected to a bonding pad, and a protective layer is provided on surfaces of the heating resistor, the individual electrode and the common electrode, the protective layer including a first protective layer which is a glass glaze layer having a transition point temperature range of 600 to 725°C or a glass glaze layer having a softening point temperature range of 700 to 870°C and covers the surface of the heating resistor; The first protective layer partially diffuses into the heating resistor, The components in the first protective layer, measured in the oxide state, are as follows: SiO 2 content is 49.4 mol % to 56.8 mol %, Al 2 O 3 content is 13.7 mol % to 26.7 mol %, CaO content is 3.5 mol % to 13.8 mol %, BaO content is 1.5 mol % to 5.9 mol %, PbO content is 4.8 mol % to 17.7 mol %, and ZrO 2 content is 1.2 mol % to 5.0 mol %. A thermal printhead heating substrate that is energy-resistant, corrosion-resistant, and abrasion-resistant.

2. Among the protective layers, a second protective layer is formed on the outer side of the first protective layer, the second protective layer being made of an insulating glass glaze layer or a conductive glass glaze layer; 2. The energy, corrosion and wear resistant heating substrate of claim 1.

3. The transition point or softening point of the second protective layer is lower than the transition point or softening point of the first protective layer.

3. The energy-resistant, corrosion-resistant, wear-resistant heating substrate for a thermal printhead according to claim 2.

4. The second protective layer is a conductive glass glaze layer, and the resistivity range is 0.01 Ω·m to 10 kΩ·m; 3. The energy-resistant, corrosion-resistant, wear-resistant heating substrate for a thermal printhead according to claim 2.

5. The protective layer is further provided with a thin-film ceramic wear-resistant protective layer, which is made of one of silicon carbide, sialon, and silicon nitride, or is a composite thin-film ceramic layer made of any two of silicon carbide, sialon, and silicon nitride.

2. The energy, corrosion and wear resistant heating substrate of claim 1.

6. The insulating glass glaze having a transition temperature of 600 to 725°C or a softening temperature of 700 to 870°C has a composition in the oxide state of SiO ２ The content is 49.4 mol% to 54.5 mol%, and Al ２ O ３ The content is 17.7 mol% to 26.7 mol%, the CaO content is 3.5 mol% to 10.5 mol%, the BaO content is 1.5 mol% to 5.0 mol%, the PbO content is 8.5 mol% to 17.7 mol%, and the ZrO ２ The content is 1.2 mol% to 3.8 mol%; 2. The energy, corrosion and wear resistant heating substrate of claim 1.

7. The insulating glass glaze having a transition temperature of 600 to 725°C or a softening temperature of 700 to 870°C has a composition in the oxide state of SiO ２ The content is 52.5 mol% to 54.5 mol%, and Al ２ O ３ The content is 17.7 mol% to 22.5 mol%, the CaO content is 6.5 mol% to 10.5 mol%, the BaO content is 2.5 mol% to 5.0 mol%, the PbO content is 8.5 mol% to 13.5 mol%, and ZrO ２ The content is 2.5 mol% to 3.8 mol%; 2. The energy, corrosion and wear resistant heating substrate of claim 1.

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