Thermal printing head capable of printing uniformly

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 in wiring, suitable for industrial production and application and uniform in printing, and is characterized in that a public COM (Component Object Model) and a public electrode are arranged in parallel, a driving IC (Integrated Circuit) is fixed on the upper surface of the public electrode, and the driving IC is fixed on the lower surface of the public electrode. A protection layer is arranged between the driving IC and the common electrode, the first bonding lead and the third bonding lead are arranged side by side and alternately arranged between the driving IC and the circuit board, and the upper parts of the bonding leads and the driving IC are protected by sealant. And the printing quality can be obviously improved.

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, simple wiring and uniform printing suitable for industrial production application. Background technology:

[0002] The key component of a thermal print head is the heating substrate for the thermal print head. The structure of the commonly used thermal print head is as follows: Figure 1 As shown, it includes a heat sink 1, on which a heating substrate for a thermal print head is provided, wherein the heating substrate includes an insulating substrate 2 and a circuit board 3, a heat storage layer 4 is provided at least partially on the surface of the insulating substrate 2, a heating resistor 5 is provided at least on the surface of the heat storage layer 4, individual electrodes 61 and a common electrode 62 are provided on both sides of the heating resistor 5, and a protective layer 71 is at least partially covered on the surfaces of the heating resistor 5, the individual electrodes 61 and the common electrode 62. One end of the common electrode 62 is connected to the heating resistor 5 along the sub-scanning direction, and the other end thereof extends along the main scanning direction; one end of the individual electrode 61 is connected to the heating resistor 5 along the sub-scanning direction, and the other end thereof is provided with a pad 9 located between the common electrode 62 and the heating resistor 5; the circuit board 3 has a common COM 63 extending along the common electrode; the driver IC is arranged above the common electrode 62 of the insulating substrate 2 or on the side of the circuit board 3 close to the insulating substrate; the first bonding wires 82 are concentratedly arranged on both sides of the driver IC and span between the common electrode and the common COM of the circuit board to achieve power connection; the second bonding wire 81 spans between the pad and the terminal of the driver IC, and the third bonding wire 83 spans between the terminal of the driver IC and the circuit board. Figure 2 As shown. In the actual printing process of the printer, when the printing point corresponding to the middle position of the driver IC is connected to the power signal introduced through the first bonding lead 82 through the common electrode 62, due to the long distance, the potential difference on the corresponding common electrode 62 is the largest, and the density of the printed image here is lighter than that of the left and right ends of the driver IC, resulting in poor uniformity of image printing quality.

[0003] In order to solve the above problems, the patent with the document publication number of JP5964101B2 and the name of the thermal print head discloses that the driver IC is placed at a position farther away from the heating plate than the common COM; the first bonding wire spans between the common electrode and the common COM; the second bonding wire spans between the pad and the driver IC; the third bonding wire spans between the driver IC and the flexible substrate; the driver IC and the bonding wire are sealed with a resin sealant. The common COM is located at a position lower than the pad and the common electrode on the insulating substrate, the terminal of the driver IC is located at a position higher than the pad and the common electrode on the insulating substrate, the second bonding wire is located at a position higher than the pad and the common electrode on the insulating substrate, and the second bonding wire is higher than the first bonding wire. This structure can effectively avoid the problem of poor uniformity of image printing quality caused by the potential difference of the common electrode. In this technical solution, the thermal print head is provided with a plurality of first bonding wires, and at least a portion of the plurality of second bonding wires cross over the first bonding wire in a direction inclined to the secondary scanning direction, and there is still a risk of short circuit between the first bonding wire and the second bonding wire. Summary of the invention:

[0004] The utility model aims at the shortcomings and deficiencies in the prior art and proposes a thermal printing head which has a reasonable structure, simple wiring and is suitable for uniform printing in industrial production applications.

[0005] The utility model achieves this through the following measures:

[0006] A thermal print head for uniform printing is provided with a heating substrate, a driver IC, a circuit board and a heat sink, wherein the heating substrate and the circuit board are fixed on the heat sink, a common COM for wiring is provided on the circuit board, a heat storage layer is provided on the heating substrate, a heating resistor, a common electrode and individual electrodes are provided on the heat storage layer, wherein the driver IC is respectively connected to the common electrode on the heating substrate and the common COM on the circuit board via bonding wires, the bonding wires include a first bonding wire for connecting the common electrode and the common COM, a second bonding wire for connecting the individual electrode and the common COM and a third bonding wire for connecting the driver IC terminal and the circuit board, characterized in that the common COM is arranged in parallel with the common electrode, the driver IC is fixed on the upper surface of the common electrode, a protective layer is provided between the driver IC and the common electrode, the first bonding wire and the third bonding wire are arranged side by side and alternately with each other between the driver IC and the circuit board, and the bonding wires and the driver IC are protected with sealant.

[0007] In order to ensure printing uniformity, the utility model arranges the first bonding leads between the common electrode and the common COM at equal intervals. Preferably, the first bonding leads are arranged between the third bonding leads at equal intervals along the main scanning direction. Furthermore, the first bonding leads can be arranged between the third bonding leads in groups at equal intervals. The number of groups n of the first bonding leads should satisfy: 3 groups ≤ n ≤ the total number of points of the driving IC, and the number of first bonding leads in each group is 1-4.

[0008] In the utility model, the protection layer between the driving IC and the common electrode is an insulating protection layer, a wear-resistant layer, a corrosion-resistant layer or an organic resin layer, or a stack of several of them.

[0009] When the utility model is working, since the first bonding lead and the third bonding lead are both located on the side of the driver IC close to the circuit board; and the first bonding lead is led out to the common COM on the circuit board along the common electrode below the driver IC, so that in the height direction, the first bonding lead is located at a position lower than the terminal of the driver IC, and can be arranged between adjacent third bonding leads at equal intervals along the main scanning direction to solve the potential difference caused by the difference in distance between the printing points; and the third bonding lead is located at a position higher than the terminal of the driver IC in the height direction, there is no short circuit risk between the first bonding lead and the third bonding lead, so that while effectively suppressing the potential change in the main scanning direction of the common electrode of the thermal print head and preventing the problem of uneven printing, the reliability of the device is significantly improved, the risk of short circuit is reduced, and high-quality printing is ensured.

[0010] Compared with the prior art, the utility model has the advantages of reasonable structure, simple wiring, suitability for industrial production application, and ability to significantly improve printing quality. Description of the drawings:

[0011] Figure 1 A side schematic diagram of a thermal print head in the prior art is shown.

[0012] Figure 2 A partially enlarged schematic diagram of a thermal head in the prior art is shown.

[0013] Figure 3 A side view of a thermal print head of the utility model is shown.

[0014] Figure 4 The schematic plan view of the heating resistor and the electrode layer in the utility model is shown.

[0015] Figure 5A partial enlarged schematic diagram of an embodiment of the utility model is shown with reference numerals: 1-heat sink, 2-insulating substrate, 3-circuit board, 4-heat storage layer, 5-heating resistor, 61-individual electrode, 62-common electrode, 63-circuit board common COM, 71-protective layer 1, 72-protective layer 2, 81-second bonding lead, 82-first bonding lead, 83-third bonding lead, 9-soldering pad, 10-driving IC10. Specific implementation method:

[0016] The specific implementation of the utility model is further described below in conjunction with the accompanying drawings.

[0017] Example:

[0018] The thermal print head for uniform printing in this example is as follows Figure 3 , as shown in 4 and 5, it comprises a heat sink 1, on which an insulating substrate 2 and a circuit board 3 are provided, and a heat storage layer 4 is provided on at least part of the surface of the insulating substrate 2; a heating resistor 5, individual electrodes 61 and a common electrode 62 are provided on at least the upper surface of the heat storage layer 4, and protective layers 71 and 72 are provided on at least part of the surface of the heating resistor 5, the individual electrodes 61 and the common electrode 62, and the protective layers 71 and 72 generally include an insulating protective layer, a wear-resistant layer, a corrosion-resistant layer, an organic resin layer, etc.;

[0019] In this example, the driver IC 10 is arranged above the protective layer 72 of the common electrode 62 of the insulating substrate, the first bonding wire 82 spans between the common electrode 62 and the common COM 63 of the circuit board; the second bonding wire 81 spans between the pad 9 connected to the individual electrode and the terminal 10 of the driver IC; the third bonding wire 83 spans between the terminal 10 of the driver IC and the circuit board 3; the first bonding wire 82 and the third bonding wire 83 are located on the side of the driver IC close to the circuit board, and the bonding wires and the top of the driver IC are protected by a sealant;

[0020] As attached Figure 5 As shown, in this example, the first bonding wires 82 are arranged between the third bonding wires 83 at equal intervals along the main scanning direction; the number of groups of the first bonding wires 82 is 3 groups ≤ n ≤ the total number of points of the driving IC; the number of each group of the first bonding wires 82 is 1 to 4;

[0021] Compared with the prior art, the thermal print head involved in this example is as follows Figure 5As shown, the first bonding lead 82 and the third bonding lead 83 are located on the side of the driver IC close to the circuit board; the first bonding lead 82 is located below the terminal 10 of the driver IC, and is arranged between adjacent third bonding leads 83 at equal intervals along the main scanning direction, and the third bonding lead 83 is located above the terminal 10 of the driver IC. There is no short circuit risk between the first bonding lead 82 and the third bonding lead 83, which can effectively suppress the potential change of the common electrode of the thermal print head in the main scanning direction and prevent the problem of uneven printing, thereby ensuring high printing quality.

Claims

1. A thermal print head for uniform printing, comprising a heating substrate, a driving IC, a circuit board and a heat sink, wherein the heating substrate and the circuit board are fixed on the heat sink, a common COM for wiring is provided on the circuit board, a heat storage layer is provided on the heating substrate, a heating resistor, a common electrode and individual electrodes are provided on the heat storage layer, wherein the driving IC is connected to the common electrode on the heating substrate and the common COM on the circuit board respectively via bonding wires, the bonding wires comprising a first bonding wire for connecting the common electrode and the common COM, a second bonding wire for connecting the individual electrode and the common COM and a third bonding wire for connecting the driving IC terminal and the circuit board, characterized in that: The common COM is arranged in parallel with the common electrode, the driver IC is fixed on the upper surface of the common electrode, a protective layer is arranged between the driver IC and the common electrode, the first bonding wire and the third bonding wire are arranged side by side and alternately with each other between the driver IC and the circuit board, and the bonding wires and the top of the driver IC are protected by sealant.

2. A thermal print head for uniform printing according to claim 1, characterized in that: The first bonding wires are arranged between the common electrode and the common COM at equal intervals.

3. A thermal print head for uniform printing according to claim 2, characterized in that: The first bonding wires are arranged between the third bonding wires at equal intervals along the main scanning direction.

4. A thermal print head for uniform printing according to claim 3, characterized in that: The first bonding wires are arranged in groups at equal intervals between the third bonding wires. The number n of the first bonding wire groups should satisfy: 3 groups ≤ n ≤ the total number of points of the driver IC. The number of the first bonding wires in each group is 1-4.

5. The uniformly printed thermal print head according to claim 1, characterized in that: The protection layer between the driving IC and the common electrode is an insulating protection layer, a wear-resistant layer, a corrosion-resistant layer, or an organic resin layer, or a stack of several of them.

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