Heating substrate for thermal printing head and 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 and the thermal printing head, which can prevent the printing head from being damaged due to static accumulation, and is characterized in that an anti-static protective film is covered above an insulating protective film; the anti-static protective film extends to the edge or corner part of the insulating protective film, the edge of the anti-static protective film is connected with a conductor outside the insulating substrate through a conductive part on the insulating substrate, and the conductive part adopts a conductive film layer or a conductive adhesive layer formed by sputtering or spraying or printing sintering.

Description

Technical Field

[0001] This utility model relates to the field of thermal printhead manufacturing technology, specifically a heating substrate for a thermal printhead and a thermal printhead that can prevent static electricity accumulation from damaging the printhead. Background Technology

[0002] As is well known, thermal printheads control printing data via printer control chips, enabling the heating element to selectively heat printing consumables such as thermal paper or ribbon to print images and text. The heating element in a thermal printhead is mounted on a ceramic substrate and electrically connected to the control IC and a common electrode via individual electrode lines. To protect the heating element and electrical components on the heating substrate, a protective layer is typically placed on the surface of an insulating substrate above the heating element and electrodes. This protective layer covers the heating element and some electrical components. The protective film on the heating element is insulating; continuous printing in a dry environment can easily generate static electricity. Because the insulating protective film cannot release static electricity, if a defect appears in the insulating film, static electricity will quickly penetrate the heating element or electrode through the defect, resulting in poor printing conditions such as white lines or white patches.

[0003] Traditional methods for eliminating static electricity in thermal printheads typically involve using through-holes on the PCB or FPC to discharge static electricity. However, since the ceramic substrate is connected to the PCB via an IC chip, static electricity may damage the heating element and IC chip during the discharge process, making it impossible to completely avoid electrostatic damage. Summary of the Invention

[0004] This invention addresses the shortcomings and deficiencies of existing technologies by proposing a thermal printhead heating substrate and thermal printhead that can significantly improve anti-static properties, thereby ensuring print quality.

[0005] This utility model achieves its purpose through the following measures:

[0006] A heating substrate for a thermal printhead includes an insulating substrate. A heat-storing glaze coating is printed and sintered on the upper surface of the insulating substrate. A heating resistor and electrode wires are disposed on the heat-storing glaze coating. An insulating protective film is disposed on the upper surface of the heating resistor. The feature is that an anti-static protective film is covered on top of the insulating protective film. The anti-static protective film extends to the edge or corner of the insulating protective film. The edge of the anti-static protective film is connected to a conductor outside the insulating substrate via a conductive part on the insulating substrate. The conductive part is a conductive film layer or a conductive adhesive layer formed by sputtering, spraying, or printing and sintering.

[0007] The insulating substrate of this invention has a conductive adhesive layer on its upper surface corresponding to the outer edge of the antistatic protective film. One side of the conductive adhesive layer is connected to the outer edge of the antistatic protective film, and the other side extends to the side of the insulating substrate to connect with an external conductor.

[0008] One end of the electrode wire of this utility model is connected to the heating resistor, and the other end is connected to the control IC. Furthermore, the heating resistor is at least 0.5 mm away from the long and short edges of the substrate. The edge of the insulating protective film covering the heating resistor extends at least 0.4 mm beyond the edge and side edge of the heating resistor. The edge of the protective film completely covers the electrode and the side of the heating resistor away from the pad. Furthermore, a non-antistatic hard protective film may be provided above the insulating protective film.

[0009] In this invention, the insulating protective film is made of silicon oxide, silicon nitride, silicon oxynitride, silicon ionomer, etc. During long-term printing, static electricity is easily generated between the insulating protective film and the printing medium. Because the protective film in contact with the rubber roller is insulating, the static electricity cannot be discharged. In addition, defects such as pinholes will be generated during the production of the insulating protective film. Static electricity will penetrate through the defects and reach the heating element layer or electrode layer, thereby damaging the heating element or control chip and causing poor printing.

[0010] To solve the static electricity problem, this invention forms an antistatic protective film on the insulating protective film, especially above the heating resistor, by means of printing or sputtering. The static electricity generated by the friction of the rubber roller or external static electricity is conducted to the external conductor through the antistatic film layer. The antistatic protective film is composed of compounds of at least two elements selected from Ta, Ti, N, C, Si, and O, preferably silicon carbide, tantalum silicon dioxide, tantalum silicon carbide, or tantalum nitride film layers.

[0011] The distance between the heating resistor and the electrode pattern of this invention and the edge of the substrate is not less than 0.5 mm, specifically 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or 1.0 mm; an insulating protective layer is provided on the heating resistor and the wire electrode to provide weather protection for the heating resistor and the electrode, and to avoid electrostatic damage, electro-corrosion or chemical corrosion. The distance between the insulating protective layer and the edge of the substrate is less than the distance between the heating resistor and the wire electrode and the edge of the substrate.

[0012] The insulating protective layer of this invention is at least 0.4 mm away from the edge of the substrate, specifically 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm or 0.9 mm; furthermore, the antistatic protective layer is at least 0.1 mm away from the edge of the insulating substrate, specifically 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm or 0.5 mm.

[0013] This utility model also proposes a thermal printhead, characterized in that it is provided with a heating substrate for a thermal printhead as described above, and an external conductor located outside the heating substrate for a thermal printhead, the external conductor being connected via a conductive portion on the side of the insulating substrate in the heating substrate for a thermal printhead.

[0014] The external conductor described in this invention is a metal heat sink or ground located below the heating substrate of the thermal printhead. The antistatic protective film is connected to the metal heat sink or ground by conductive adhesive or conductive brush to discharge static electricity from the surface of the heating substrate.

[0015] In use, this invention utilizes an anti-static protective layer covering the insulating protective film layer above the heating resistor and electrode wires in the thermal printhead. This anti-static protective layer extends upwards and downwards from the heating element, not exceeding the pad position downwards and not exceeding the insulating layer upwards. It is connected to an external conductor at the tip of the edge of the insulating substrate (the printing ineffective area). Specifically, it is connected to an external conductor such as a metal heat sink, conductive brush, or ground by conductive adhesive or other conductive materials laid along the side of the insulating substrate, thereby quickly releasing the generated static electricity.

[0016] Compared with the prior art, this utility model has the advantages of reasonable structure, reliable process, avoiding damage to heating resistors or related components on PCB board, and ensuring electrostatic discharge effect. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the planar structure of the heating substrate for thermal printheads in the prior art.

[0018] Figure 2 yes Figure 1 A schematic diagram of the cross-sectional structure.

[0019] Figure 3 This is a planar schematic diagram of the heating substrate with an insulating protective film in this utility model.

[0020] Figure 4 yes Figure 3 A schematic diagram of the cross-sectional structure.

[0021] Figure 5 This is a schematic diagram of the heating substrate corresponding to the hard protective film layer above the insulating protective film layer in this utility model.

[0022] Figure 6 yes Figure 5 A schematic diagram of the cross-sectional structure.

[0023] Figure 7 This is a schematic diagram of one embodiment of the present invention in which static electricity on the heating substrate of the thermal printhead is discharged through a metal heat sink.

[0024] Figure 8 This is a schematic diagram of the second embodiment of the present invention, in which static electricity on the heating substrate of the thermal printhead is discharged through a metal heat sink.

[0025] Reference numerals in the figures: 1. Insulating substrate; 2. Heat storage glaze coating; 3. Electrode conductor layer; 4. Heating resistor; 5. Insulating protective film; 6. Rigid protective film; 7. Antistatic protective film; 8. Conductive adhesive; 9. Individual electrode; 10. Common electrode; 11. Bonding electrode; 12. Metal heat sink; 13. Conductive brush. Detailed Implementation

[0026] The technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this patent. Obviously, the described embodiments are only a part of the embodiments of this patent, and not all of the embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent. Example

[0027] As attached Figure 3 As shown, this example provides a heating substrate for a thermal printhead. The surface of the heating substrate for the thermal printhead is provided with a heat-storing glaze coating 2, a heating resistor 4, and electrode wires 9. The heating resistor 4 is disposed on the heat-storing glaze coating 2, and the electrode wires 9 are partially disposed on the heat-storing glaze coating 2 and connected to the heating resistor 4. Electrode wires are formed on the patterned electrode wire layer 3. The electrode wires include at least lead-out electrodes, bonding electrode patterns, and common electrode patterns. The heating resistor layer 4 is patterned by light leakage etching and other processes. Electrode wires are formed on the patterned electrode wire layer 3. The electrode wires include at least individual lead-out electrodes 9, common lead-out electrodes 10, and bonding electrodes 11. The heating resistor 4 and the electrode wires 9 cover the effective printing width. After printing or sputtering, the effective size of the paper output side electrode and the heating resistor 4 is not less than 0.5 mm from the long and short edges of the substrate. They are all covered with a partial insulating protective film 5. The insulating protective film 5 extends beyond the upper edge (away from the pad side) and side edge of the heating resistor 4 by not less than 0.4 mm.

[0028] As attached Figure 4 As shown, an antistatic protective film 7 is provided above the insulating protective film 5. The upper edge of the antistatic protective film 7 is connected to the upper surface of the insulating substrate 1 by spraying, sputtering, printing a conductive layer or applying conductive adhesive 8 to conduct the static electricity on the insulating protective film 5 to the metal heat sink 12.

[0029] In this example, the insulating protective film 5 is made of silicon oxide insulating film. During long-term printing, the insulating protective film 5 and the printing medium are prone to static electricity. Because the protective film in contact with the rubber roller is insulating, the static electricity cannot be discharged. During the production of the protective film, defects such as pinholes will be generated. Static electricity will penetrate the defects and reach the heating element layer or electrode layer, thereby damaging the heating element or control chip and causing poor printing. In order to solve the static electricity problem, an anti-static protective film 7 is set on the insulating protective film 5, especially above the heating element, by printing or sputtering. The static electricity generated by the friction of the rubber roller or external static electricity is connected to the heat sink or other conductors through the anti-static film.

[0030] As attached Figure 4 As shown, in this example, the antistatic protective film 7 is at least 0.1 mm away from the edge of the substrate, specifically it can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm or 0.5 mm. The antistatic protective film 7 is made of silicon carbide, tantalum silicon dioxide, tantalum silicon carbide, tantalum nitride or other film layers. In this example, the heating resistor 4 and the electrode pattern are at least 0.5 mm away from the edge of the substrate, specifically it can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or 1.0 mm.

[0031] As attached Figure 7 Or attached Figure 8 As shown, this example also proposes a thermal printhead, which uses the thermal printhead heating substrate described in this example and is provided with a metal heat sink 12. The antistatic protective film 7 is connected to the metal heat sink 12 through conductive adhesive 8 or by setting a conductive brush 13 or other conductive materials to release the generated static electricity as quickly as possible. Example

[0032] As attached Figure 5 As shown, this example provides a heating substrate for a thermal printhead. The surface of the heating substrate for the thermal printhead is provided with a heat storage glaze coating 2, a heating resistor 4, and an electrode wire layer 3. The heating resistor 4 is disposed on the heat storage glaze coating 2, and the electrode wire layer 3 is partially disposed on the heat storage glaze coating 2 and connected to the heating resistor 4. The heating element and the wire electrode cover the effective printing width. After printing or sputtering, the effective size of the paper output side electrode and the heating element is not less than 0.5 mm from the long and short edges of the substrate. The insulating protective film covering the entire part is not less than 0.4 mm from the upper edge and side edge of the heating element.

[0033] Unlike Example 1, this example covers the insulating protective film 5 with a rigid protective film 6, and then an antistatic protective film 7 is provided on top of the rigid protective film 6, as shown in the attached figure. Figure 6 As shown, at the junction of the upper edge of the antistatic protective film 7 and the upper surface of the insulating substrate 1, the electrostatic connection to the metal heat sink 12 is conducted out by spraying, sputtering, printing a conductive layer or applying conductive adhesive 8, or by setting a conductive brush 13.

[0034] Compared with the prior art, this utility model has the advantages of reasonable structure, reliable process, avoiding damage to heating resistors or related components on PCB board, and ensuring electrostatic discharge effect.

Claims

1. A heat-generating substrate for a thermal printhead, comprising an insulating substrate, a heat-accumulating enamel coating layer formed by printing and sintering on the upper surface of the insulating substrate, a heat-generating resistor and an electrode lead wire disposed on the heat-accumulating enamel coating layer, and an insulating protective film disposed on the upper surface of the heat-generating resistor, characterized in that, The upper side of the insulation protective film is covered by an anti-static protective film, which extends to the edge or corner of the insulation protective film, and the edge of the anti-static protective film is connected to the conductor outside the insulation substrate through the conductive part on the insulation substrate, which is formed by sputtering, spraying or printing sintering.

2. The heat generating substrate for a thermal printhead according to claim 1, wherein The upper side of the insulation protective film is covered by an anti-static protective film, which extends to the edge or corner of the insulation protective film, and the edge of the anti-static protective film is connected to the conductor outside the insulation substrate through the conductive part on the insulation substrate, which is formed by sputtering, spraying or printing sintering.

3. The heat generating substrate for a thermal printhead according to claim 1, wherein The electrode wire is connected to the heat-generating resistor at one end and to the control IC at the other end, the heat-generating resistor is at a distance of not less than 0.5mm from the long and short edges of the insulation substrate, the edge of the insulation protective film covering the heat-generating resistor exceeds the edge of the heat-generating resistor by not less than 0.4mm, and the edge of the insulation protective film completely covers the electrode and the side of the heat-generating resistor away from the pad.

4. The heat generating substrate for a thermal printhead according to claim 3, wherein The upper side of the insulation protective film is covered by an anti-static protective film, which extends to the edge or corner of the insulation protective film, and the edge of the anti-static protective film is connected to the conductor outside the insulation substrate through the conductive part on the insulation substrate, which is formed by sputtering, spraying or printing sintering.

5. The heat generating substrate for a thermal printhead according to claim 1, wherein The insulation protective film is made of silicon oxide, silicon nitride, silicon oxynitride or sialon film material.

6. The heat generating substrate for a thermal printhead according to claim 1, wherein The anti-static protective film is made of silicon carbide, tantalum silicon dioxide, tantalum silicon carbide or tantalum nitride film.

7. A thermal printhead, characterized by, The heat-generating substrate for thermal print head as claimed in any one of claims 1-6 is provided with an external conductor outside the heat-generating substrate for thermal print head, which is connected through the conductive part on the side of the insulation substrate in the heat-generating substrate for thermal print head, and the external conductor is a metal heat sink or ground below the heat-generating substrate for thermal print head, and the anti-static protective film is connected to the metal heat sink or ground through conductive glue or conductive brush.

Images