Heating substrate for thermal printing head with uniform printing concentration

Abstract

The utility model relates to the technical field of thermal printing head manufacturing, in particular to a heating substrate for a thermal printing head with uniform printing concentration, which is reasonable in structure and capable of compensating printing concentration deviation caused by resistance deviation of a common electrode wire so as to remarkably improve printing quality. The width of the local ground coat layer is gradually reduced from the two ends to the center, the width range of the local ground coat layer is 0.5-2.0 mm, and the thickness range of the local ground coat layer is 10-60 microns.

Description

Technical field:

[0001] The utility model relates to the technical field of thermal print head manufacturing, in particular to a heating substrate for a thermal print head with a reasonable structure, capable of compensating for a printing concentration deviation caused by a common electrode wire resistance deviation, thereby significantly improving the printing quality and achieving a uniform printing concentration. Background technology:

[0002] As we all know, a thermal print head is equipped with many thermal heating units that are linearly and continuously arranged at a certain resolution. By applying a corresponding pulse voltage to each heating unit, the heating unit produces a Joule heat effect, converting electrical energy into thermal energy. The thermal energy generated by the heating unit is used to act on the thermal medium to make the thermal medium color. Based on the above principle, the more heating points there are at the same time, the greater the current in the circuit, the greater the voltage drop generated by the line, and the closer the heating unit is to the power supply end on the heating substrate, the less affected by the voltage drop, and the farther it is from the power supply end, the greater the impact of the voltage drop. In existing thermal print heads, the power supply is usually connected to the common electrode from both ends of the print head. This structure causes the middle part of the print head to be most affected by the voltage drop, so the overall printing often has a phenomenon of deep concentration at both ends and shallow concentration in the middle.

[0003] The utility model patent with publication number CN208277640U discloses a method of adjusting the size of heating resistors at different positions to adjust the heating value of the heating resistors, thereby achieving heat matching between the two ends and the middle of the print head and achieving uniform printing concentration. However, this method is only suitable for thin-film print heads with separated heating resistors produced by photolithography etching process, and is not applicable to thick-film print heads with continuous heating resistors produced by drawing.

[0004] The utility model patent with publication number CN217415272U discloses a method of adjusting the contact state between paper and heating resistor by adjusting the thickness of electrodes on both sides of heating resistor at different positions to achieve uniform printing concentration. However, this method is only applicable to thin film print heads in which the electrodes are higher than the heating resistor, and is not applicable to continuous thick film print heads of heating resistors produced by drawing.

[0005] The utility model patent with publication number CN214563910U discloses a method of achieving uniform printing concentration by opening a heat dissipation adjustment groove in the area corresponding to the heating resistor on the lower side of the substrate, but the heat needs to be conducted from the front to the back of the ceramic substrate. The heat conduction distance is long and the improvement effect cannot be quickly reflected in the printing effect. Summary of the invention:

[0006] In view of the shortcomings and deficiencies in the prior art, the utility model proposes a heating substrate for a thermal print head with a reasonable structure, which can compensate for the printing concentration deviation caused by the resistance deviation of the common electrode wire, thereby significantly improving the printing quality and having a uniform printing concentration.

[0007] The utility model achieves this through the following measures:

[0008] A heating substrate for a thermal print head with uniform printing concentration is provided, comprising an insulating substrate, a heating resistor and an electrode wire are provided on the insulating substrate, a local base glaze layer is provided in the area corresponding to the setting of the heating resistor on the upper surface of the insulating substrate, the heating resistor is provided on the local base glaze layer, and the heating resistor is connected to the electrode wire, and is characterized in that the width of the local base glaze layer gradually narrows from both ends to the center, and the width range of the local base glaze layer is 0.5-2.0mm, and the thickness range is 10-60μm.

[0009] The local bottom glaze layer of the utility model has a straight side on one side and an arc-shaped notch on the other side, so as to form a defect portion gradually widening from both ends to the center on only one side of the local bottom glaze layer to meet the arrangement requirements of the electrode wires.

[0010] The utility model provides a heating resistor on the top of the local bottom glaze layer, and the local bottom glaze layer has a convex arc upper surface with a consistent curvature radius corresponding to the heating resistor setting area, thereby effectively ensuring the heat storage effect during the printing process.

[0011] One side edge of the local bottom glaze layer of the utility model is provided with a defect portion with a width not exceeding 30% of the maximum width of the local bottom glaze layer. Furthermore, the width of the central part of the local bottom glaze layer is 75-95% of the width at both ends. Furthermore, in order to ensure effective contact between the printing medium and the printing rubber roller during the printing process, the maximum width of the defect portion of the local bottom glaze layer is 5%-25% of the overall width of the local bottom glaze layer.

[0012] The electrode lead wire of the utility model comprises individual electrodes and common electrodes, and the surfaces of the heating resistor body and parts of the individual electrodes and the common electrodes are provided with a protective layer.

[0013] The utility model The defective part of the local bottom glaze layer of the utility model can be obtained by removing part of the glaze layer in the electrode-free distribution area of ​​the normal local bottom glaze layer by mask etching. The etched side of the local bottom glaze layer is the side where the individual electrode is not located. The special local bottom glaze structure obtained by mask etching is the normal local bottom glaze layer structure. Along the main printing direction, the top curvature radius is consistent, and the width gradually decreases from the two ends to the middle.

[0014] The beneficial effect of this scheme of the utility model lies in that the above-mentioned thermal print head with uniform printing density uses a heating substrate to change the cross-sectional area of ​​the local bottom glaze layer at different positions, thereby changing the heat storage capacity of the local bottom glaze layer at different positions and its heat conduction efficiency to the insulating substrate, so that the heat storage capacity of the local bottom glaze layer and the heat conduction efficiency to the insulating substrate gradually decrease from both ends to the middle, which can compensate for the printing density deviation caused by the resistance deviation of the common electrode wire, make the heat obtained by the paper from the heating substrate relatively uniform, and can make the printing density uniform. At the same time, it has the advantages of strong universality and fast effect response speed. Description of the drawings:

[0015] Attached Figure 1 It is a cross-sectional schematic diagram of a thermal printing head heating substrate in the prior art.

[0016] Attached Figure 2 It is a top view of a local bottom glaze layer of a thermal print head heating substrate in the prior art.

[0017] Attached Figure 3 The present invention is a schematic diagram of the distribution of electrodes and heating resistors on the top of a local bottom glaze in a thermal printing head heating substrate in the prior art.

[0018] Attached Figure 4 It is a schematic cross-sectional view of a local bottom glaze structure of a heating substrate for a thermal print head in the utility model.

[0019] Attached Figure 5 It is a schematic top view of a partial bottom glaze structure of Example 1 of the utility model.

[0020] Reference numerals: protective layer 1 , heating resistor 2 , electrode lead 3 , individual electrode 3 a , common electrode 3 b , partial underglaze layer 4 , insulating substrate 5 . Specific implementation method:

[0021] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0022] Embodiment 1:

[0023] This example provides a heating substrate for a thermal print head with uniform printing density, including an insulating substrate 5, a partial bottom glaze layer 4 is provided on the insulating substrate 5, an electrode 3 is provided on the partial bottom glaze layer 4, wherein the electrode 3 is divided into an individual electrode 3a and a common electrode 3b, a heating resistor 2 is provided on the electrode 3, the heating resistor 2 is arranged along the main printing direction, and is connected to the individual electrode 3a and the common electrode 3b, a protective layer 1 is covered on the surface of the heating resistor 2 and part of the individual electrode 3a and the common electrode 3b, wherein the power supply is connected to the common electrode 3b through both ends respectively;

[0024] In this example, the local bottom glaze layer 4 is made of glass glaze sintered at high temperature, with a width of 0.5 to 2 mm and a maximum thickness of 10 to 60 μm. The curvature radius of the top heating resistor 2 along the main printing direction remains consistent, and the width of the local bottom glaze layer 4 gradually decreases from the two ends to the middle along the main printing direction. The width of the local bottom glaze layer 4 is the largest at the two ends and the smallest in the middle. The width in the middle is 75% to 95% of the width at the two ends. The optimal value needs to be determined based on the actual length, width, thickness and other dimensions of the local bottom glaze layer.

[0025] The utility model relates to a heating substrate for a thermal print head with uniform printing density, which changes the cross-sectional area of ​​the local bottom glaze layer at different positions, thereby changing the heat storage and heat conduction efficiency of the local bottom glaze layer at different positions, so that the heat storage of the local bottom glaze layer and its heat conduction efficiency to the insulating substrate gradually decrease from both ends to the middle along the main printing direction, and can compensate for the printing density deviation caused by the resistance deviation of the common electrode wire, so that the heat obtained by the paper from the heating substrate is relatively uniform, and the printing density can be better uniform. At the same time, it has the advantages of strong universality and fast effect response speed.

Claims

1. A heating substrate for a thermal print head with uniform printing density, comprising an insulating substrate, a heating resistor and an electrode lead being arranged on the insulating substrate, a local base glaze layer being arranged in an area corresponding to the setting area of ​​the heating resistor on the upper surface of the insulating substrate, the heating resistor being arranged on the local base glaze layer, and the heating resistor being connected to the electrode lead, characterized in that: The width of the local bottom glaze layer gradually narrows from the two ends to the center, and the width range of the local bottom glaze layer is 0.5-2.0 mm, and the thickness range is 10-60 μm.

2. The heating substrate for a thermal print head with uniform printing density according to claim 1, characterized in that: One side of the partial bottom glaze layer has a straight side, and the other side has an arc-shaped notch, so as to form a defect portion gradually widening from both ends to the center on only one side of the partial bottom glaze layer to meet the arrangement requirements of the electrode wires.

3. The heating substrate for a thermal print head with uniform printing density according to claim 1, characterized in that: A heating resistor is arranged on the top of the local bottom glaze layer, and the local bottom glaze layer has a convex arc-shaped upper surface with a consistent curvature radius corresponding to the heating resistor arrangement area.

4. The heating substrate for a thermal print head with uniform printing density according to claim 2, characterized in that: One side of the partial bottom glaze layer is provided with a defect portion whose width does not exceed 30% of the maximum width of the partial bottom glaze layer.

5. The heating substrate for a thermal print head with uniform printing density according to claim 4, characterized in that: The width of the partial bottom glaze layer at the center is 75-95% of the width at both ends.

6. The heating substrate for a thermal print head with uniform printing density according to claim 2, characterized in that: The maximum width of the defect portion of the local bottom glaze layer is 5%-25% of the overall width of the local bottom glaze layer.

7. The heating substrate for a thermal print head with uniform printing density according to claim 1, characterized in that: The electrode wires include individual electrodes and common electrodes, and the surfaces of the heating resistor and parts of the individual electrodes and the common electrodes are provided with a protective layer.

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