Heating substrate for thermal printing head

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, which is reasonable in structure, simple and convenient in process and capable of effectively improving the heat utilization rate of a product so as to realize energy conservation and prolong the service life of the product, and is provided with an insulating substrate, and a ground coat layer is arranged on the surface of the insulating substrate. The upper surface of the ground coat layer is provided with an electrode lead and a heating resistor body, the partial area of the electrode lead and the upper surface of the heating resistor body are covered with an insulation protection layer, the insulation protection layer on the upper surface of the heating resistor body is a beta-Si3N4 insulation protection layer, and the thickness range of the beta-Si3N4 insulation protection layer is 3-5 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 and simple process, which can effectively improve the heat utilization rate of the product, thereby achieving energy saving and extending the service life of the product. Background technology:

[0002] As is well known, the heating substrate of a thermal printhead consists of an insulating substrate with an underglaze layer applied to its surface. Electrode leads and a heating resistor are arranged on the upper surface of the underglaze layer. Parts of the electrode leads and the heating resistor are covered with a wear-resistant insulating protective layer, while the pads are not. A driver IC is connected to the pads on the heating substrate via a bonding or bumping process. The driver IC is protected above the component with epoxy encapsulant. The operating principle is that the printer host receives collected information, which is then pulsed and applied to the heating resistor of the thermal printhead after circuitry is driven. The Joule heat generated by the heating resistor is directly transferred to thermal paper or to regular paper via a thermal transfer ribbon via thermal transfer, quickly recording the image and text. In the prior art, the insulating protective layer covering the heating resistor to improve wear resistance is often made of materials such as glass glaze. This has low thermal conductivity and dissipates significant Joule heat to the surrounding environment, resulting in significant Joule heat loss. To increase print density, the printing energy must be increased, which accelerates the wear of the heating element and shortens the product's lifespan. Summary of the invention:

[0003] In view of the shortcomings and deficiencies in the prior art, the utility model proposes a heating substrate for a thermal print head which has a reasonable structure and a simple process and can effectively improve the heat utilization rate of the product, thereby achieving energy saving and extending the service life of the product.

[0004] The utility model is achieved through the following measures:

[0005] A heating substrate for a thermal print head comprises an insulating substrate, an underglaze layer provided on the surface of the insulating substrate, electrode wires and a heating resistor arranged on the upper surface of the underglaze layer, and an insulating protective layer covering portions of the electrode wires and the upper surface of the heating resistor. The insulating protective layer on the upper surface of the heating resistor is a β-Si3N4 insulating protective layer having a thickness in the range of 3-5 μm.

[0006] The thermal conductivity of the β-Si3N4 insulating protective layer in the direction perpendicular to the heating resistor is 57-169 W / mk.

[0007] The β-Si3N4 insulating protective layer of the utility model is realized by magnetron sputtering technology under the action of an external enhanced magnetic field, and the β-Si3N4 insulating protective layer is located on the surface of the heating resistor on the insulating substrate.

[0008] A low-temperature ceramic layer or ink layer is provided on the upper surface of a partial area of ​​the electrode wire of the utility model as an insulating protective layer to achieve packaging protection of the electrode wire. Furthermore, the thickness of the low-temperature ceramic or ink layer used in the electrode wire portion is in the range of 5-20um, and the low-temperature ceramic or ink layer used in the electrode wire portion is achieved by screen printing and then drying.

[0009] In the present invention, a pad is further provided on the insulating substrate, which is not covered with an insulating protective layer. The driver IC and the pad on the heating substrate are connected by a bonding or BUMP process, and the top of the driver IC is protected by epoxy resin encapsulation glue.

[0010] When in use, the utility model replaces the ordinary insulating protective layer above the heating resistor in the prior art with a low thermal conductivity and dissipates heat to the surrounding environment, resulting in a large amount of Joule heat loss. By replacing the ordinary insulating protective layer above the heating element with a β-Si3N4 insulating protective layer with a thermal conductivity of 57-169W / mk perpendicular to the heating resistor, the speed of heat transfer to the printing medium can be increased, the heat dissipation to the surrounding environment is reduced, the utilization rate of Joule heat is greatly improved, energy saving effect is achieved, and the service life of the product is prolonged. Description of the drawings:

[0011] Attachment Figure 1 It is a structural diagram of the present utility model.

[0012] Attachment Figure 2 yes Figure 1 Cross-section view in the AA direction.

[0013] Figure numerals: insulating substrate 1, base glaze layer 2, electrode wire 3, heating resistor 4, β-Si3N4 insulating protective layer 5, insulating protective layer 6, driver IC 7, epoxy resin encapsulation glue 8, electrode wire setting area 9, heating working area 10. Specific implementation method:

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0015] Example:

[0016] As attached Figure 1As shown, this example provides a heating substrate for a thermal print head that saves energy while increasing product life. The substrate comprises an insulating substrate 1, a base glaze layer 2 is formed on the insulating substrate 1 by screen printing and sintering, a metal layer is formed at a set position on the base glaze layer 2 by a thick film process or a thin film process, and then an electrode wire 3 is formed by processes such as glue coating, light leakage, and etching; a heating resistor 4 is formed in the central area of ​​the electrode wire 3 by a thick film process or a thin film process; a β-Si3N4 insulating protective layer 5 with a thickness of 3-5 μm and a thermal conductivity of 57-169 W / mk perpendicular to the heating resistor is formed on the surface of the heating resistor 4 on the insulating substrate by magnetron sputtering technology under the action of an external enhanced magnetic field; a portion of the electrode wire 3 where an insulating protective layer 6 is required is screen-printed with low-temperature ceramic slurry or ink and dried on the electrode wire portion to form a 5-20 μm insulating protective layer 6;

[0017] As attached Figure 2 As shown, in this example, the β-Si3N4 insulating protective layer 5 completely covers the upper surface of the heating resistor 4 (the area where the heating working area 10 is located), and further extends to cover the base glaze layer 2 on both sides of the heating resistor 4, and partially overlaps with the insulating protective layer 6 in the area where the electrode wire 3 is set, completing the packaging protection of the heating resistor 4 and the electrode wire 3;

[0018] The driver IC 7 and the thermal print head substrate are connected by a bonding or BUMP process, and the driver IC 7 is encapsulated and protected with an epoxy resin encapsulation glue 8 by a casting or printing process.

[0019] The beneficial effect of this solution of the utility model is that by replacing the ordinary insulating protective layer above the heating element with a β-Si3N4 insulating protective layer with a thermal conductivity of 57-169W / mk perpendicular to the direction of the heating resistor, heat loss is reduced, the utilization rate of Joule heat is greatly improved, energy saving is achieved, and the service life of the product is increased.

Claims

1. A heating substrate for a thermal print head, comprising an insulating substrate, an underglaze layer provided on the surface of the insulating substrate, an electrode lead and a heating resistor arranged on the upper surface of the underglaze layer, and an insulating protective layer covering a portion of the electrode lead and the upper surface of the heating resistor, characterized in that: The insulating protective layer on the upper surface of the heating resistor is a β-Si3N4 insulating protective layer, and the thickness of the β-Si3N4 insulating protective layer is in the range of 3-5 μm.

2. The heating substrate for a thermal print head according to claim 1, wherein: A low-temperature ceramic layer or ink layer with a thickness ranging from 5 to 20 μm is provided on the upper surface of a partial area of ​​the electrode wire as an insulating protective layer. The β-Si3N4 insulating protective layer completely covers the upper surface of the heating resistor, and extends to cover the base glaze layer on both sides of the heating resistor, forming a partial overlap with the insulating protective layer in the area where the electrode wire is set.

3. The heating substrate for a thermal print head according to claim 1, wherein: The insulating substrate is further provided with a soldering pad which is not covered with an insulating protective layer. The driving IC is connected to the soldering pad on the heating substrate. The top of the driving IC is protected by epoxy resin encapsulation glue.

4. The heating substrate for a thermal print head according to claim 1, wherein: The β-Si3N4 insulating protective layer is perpendicular to the direction of the heating resistor, and the thermal conductivity perpendicular to the direction of the heating resistor is 57-169 W / mk.

Images