Thermal printing head

Abstract

The utility model relates to the technical field of thermal printing head manufacturing, in particular to a thermal printing head which is reasonable in structure, simple and convenient to disassemble and assemble, and capable of effectively improving the welding accuracy, reliability and production efficiency among product parts, and is characterized in that a green glaze layer of a PCB (Printed Circuit Board) is also provided with an enhanced protection layer with a welding positioning identification function; the reinforcing protection layer is arranged on one side of the bonding pad, is strip-shaped and is parallel to a heating resistor body on the heating substrate for the thermal printing head, so that the problems of welding deviation, welding dislocation and repeated alignment during welding of a flexible circuit board can be effectively solved, the welding production efficiency is greatly improved, the time cost is saved, and the production efficiency is improved. And meanwhile, the thickness of the reinforced protective layer is more than two times that of the green glaze layer below the reinforced protective layer, so that the green glaze layer can be prevented from being scratched by a tool when the flexible circuit board is replaced and the protective glue is removed, the bottom copper lead is prevented from being exposed, and the service life of the product is prolonged.

Description

Technical field:

[0001] The utility model relates to the technical field of thermal print head manufacturing, in particular to a thermal print head with reasonable structure, easy assembly and disassembly, and capable of effectively improving welding accuracy, reliability and production efficiency between product components. Background technology:

[0002] With the rapid development of the information industry, thermal printers are widely used. Among them, the thermal print head is the core component of the thermal printer. Its working principle is to apply the information collected by the host computer through the printer control motherboard to the heating resistor in the form of pulses after being driven by the circuit. The heating resistor then generates Joule heat energy and transmits it directly to the thermochromic thermal printing paper in the form of conduction, thereby recording text or images. Among them, the printer control motherboard and the thermal print head are connected by a socket or a flexible circuit board plug-in to achieve the final print output. In actual production, when the thermal print head uses a crimping machine to weld the flexible circuit board, the pad is blocked by the film on the flexible circuit board, which will cause inaccurate alignment and repeated alignment. After welding is completed, there will often be problems of welding position offset and welding misalignment. Moreover, when replacing the flexible circuit board, it is necessary to use tools to first peel off the protective glue covering the pressed end from one side. Since the green glaze layer of the PCB board under the protective glue is thin and has average scratch resistance, the green glaze layer may be scratched during this process, causing the copper wire covering the bottom to be exposed, affecting the subsequent use of the product. Summary of the invention:

[0003] In view of the shortcomings and deficiencies in the prior art, the utility model provides a thermal print head which has a reasonable structure, is easy to assemble and disassemble, and can effectively improve the welding accuracy, reliability and production efficiency between product components.

[0004] The utility model achieves this through the following measures:

[0005] A thermal print head is provided with a heat dissipation base, on which a heating substrate for the thermal print head, a control IC, and a PCB printed circuit board are provided, wherein the heating substrate for the thermal print head is connected to the PCB printed circuit board, and the joint is encapsulated by an encapsulation glue layer, the control IC is adhered to the heating substrate for the thermal print head or the PCB printed circuit board, and is connected to the electrode wire on the heating substrate for the thermal print head, the PCB printed circuit board is provided with a green glaze layer and a soldering pad for connecting to a flexible circuit board, and is characterized in that a reinforcing protective layer having a welding positioning mark function is also provided on the green glaze layer of the PCB printed circuit board, the reinforcing protective layer is arranged on one side of the soldering pad, the reinforcing protective layer is in a strip shape and is arranged parallel to the heating resistor on the heating substrate for the thermal print head.

[0006] The color of the enhanced protection layer of the utility model is different from that of the green glaze layer, preferably the color is yellow or white, and the preferred material is solder resist glaze.

[0007] The thickness of the enhanced protective layer of the utility model is more than twice the thickness of the green glaze layer. Furthermore, the thickness of the enhanced protective layer can be 20 μm.

[0008] The front side of the enhanced protective layer with welding positioning mark function in the utility model starts from the edge of the PCB pressure welding pad in the width direction and is flush with the bottom green glaze layer, and the rear side extends to the pressure welding pad adjacent to the PCB printed circuit board and is flush with the bottom green glaze layer.

[0009] The heating substrate for the thermal print head of the utility model comprises a ceramic substrate, on which an underglaze layer, a common electrode, individual electrodes and a heating resistor are arranged.

[0010] The utility model provides an enhanced protective layer with a welding positioning mark function on the green glaze layer adjacent to one side of the pad on the PCB printed circuit board. The positioning mark protective layer has the characteristic of visually obvious color. When welding the flexible circuit board, it is only necessary to place one side of the flexible circuit board on the starting position of the positioning mark protective layer. The operation is simple and convenient, the alignment is accurate, and the problems of welding offset, welding dislocation, and repeated alignment when welding the flexible circuit board can be effectively solved, which greatly improves the welding production efficiency and saves time cost. At the same time, because the thickness of the enhanced protective layer is more than twice the thickness of the green glaze layer below it, it can prevent the green glaze layer from being scratched by the tools used when replacing the flexible circuit board and removing the protective glue, avoid exposing the bottom copper wire, and improve the service life of the product. Description of the drawings:

[0011] Attached Figure 1 It is a schematic diagram of the top structure of the utility model.

[0012] Attached Figure 2 It is a schematic diagram of the cross-sectional structure of the utility model.

[0013] Explanation of the symbols in the accompanying drawings: base 1, insulating substrate 2, heating resistor 3, control IC 4, PCB printed circuit board 5, green glaze layer 6, enhanced protective layer 7, packaging glue 8, solder pad 9. Specific implementation method:

[0014] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0015] Example:

[0016] See attached Figure 1 , Attachment Figure 2This example provides a thermal print head with an enhanced protective layer having a welding positioning mark function on one side of the pad on the PCB printed circuit board. The enhanced protective layer 7 is in a strip shape and is located parallel to the heating resistor 3 on the heating substrate of the thermal print head. In this example, an insulating substrate 2 and a PCB printed circuit board 5 are provided on the base 1. A partial or complete base glaze layer is provided on the insulating substrate 2. An electrode layer and a heating resistor 3 are provided on the base glaze layer. The electrode layer includes a common electrode and an individual electrode. The heating resistor 3 is arranged between the common electrode and the individual electrode along the main printing direction as a heating element that generates Joule heat energy. A control IC 4 is provided on the PCB printed circuit board 5 or the insulating substrate 2. Figure 1 As shown, the green glaze layer 6 and the pad 9 are distributed on the surface of the PCB printed circuit board 5, and the enhanced protection layer 7 is distributed on the upper part of the green glaze layer 6;

[0017] The control IC4 is connected to the electrodes on the insulating substrate 2 via one of gold, silver and copper wires, and a packaging glue 8 is used to package and protect the connection between the insulating substrate 2 and the PCB printed circuit board 5 and above the control IC4;

[0018] In this example, the enhanced protective layer with the function of welding positioning mark has a thickness of 20 μm, which is twice the thickness of the green glaze layer below it. The material color is other significant colors different from the green glaze layer, which is visually obvious. The preferred color is yellow or white, and the preferred material is solder resist;

[0019] After adding the enhanced protective layer with the function of welding positioning mark, the enhanced protective layer has the characteristics of obvious visual, accurate alignment, simple and convenient welding operation, which can avoid the problems of welding offset and repeated alignment, improve welding production efficiency and save time cost. At the same time, because the thickness of the enhanced protective layer is twice the thickness of the green glaze layer below it, it can effectively prevent the green glaze layer from being scratched by the tools used when replacing the flexible circuit board and removing the protective glue, avoid exposing the bottom copper wire, and increase the service life of the product.

Claims

1. A thermal print head, provided with a heat dissipation base, on which a heating substrate for a thermal print head, a control IC, and a PCB printed circuit board are provided, wherein the heating substrate for the thermal print head is connected to the PCB printed circuit board, and the joint is encapsulated by an encapsulation glue layer, the control IC is adhered to the heating substrate for the thermal print head or the PCB printed circuit board, and is connected to the electrode wire on the heating substrate for the thermal print head, the PCB printed circuit board is provided with a green glaze layer and a pad for connecting to a flexible circuit board, characterized in that: The green glaze layer of the PCB printed circuit board is also provided with a reinforced protective layer having a welding positioning mark function. The reinforced protective layer is arranged on one side of the soldering pad. The reinforced protective layer is in a strip shape and is arranged parallel to the heating resistor on the heating substrate for the thermal print head.

2. A thermal print head according to claim 1, characterized in that: The color of the enhanced protective layer is different from the color of the green glaze layer.

3. A thermal print head according to claim 1, characterized in that: The material of the enhanced protection layer is solder resist.

4. A thermal print head according to claim 1, characterized in that: The thickness of the reinforced protective layer is more than twice the thickness of the green glaze layer.

5. A thermal print head according to claim 1, characterized in that: The heating substrate for the thermal print head of the enhanced protection layer includes a ceramic substrate, on which an underglaze layer, a common electrode, individual electrodes and a heating resistor are arranged.

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