Thermal print head

• US 10,639,906 B1
• Filed: 12/12/2019
• Issued: 05/05/2020
• Est. Priority Date: 06/08/2017
• Status: Active Grant

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: Aoki, Yoichi, Yamamoto, Tadashi, Nakanishi, Masatoshi
• Primary Examiner(s): Mruk, Geoffrey S
• Application Number:
  US16/712,133
• Publication Number:
  US 20200114657A1
• Time in Patent Office: 145 Days
• CPC Class Codes: B41J 2/3351 Electrode layers
• CPC Class Codes: B41J 2/33515 Heater layers
• CPC Class Codes: B41J 2/3352 Integrated circuits
• CPC Class Codes: B41J 2/33525 Passivation layers
• CPC Class Codes: B41J 2/3353 Protective layers
• CPC Class Codes: B41J 2/33535 Substrates
• CPC Class Codes: B41J 2/3354 characterised by geometry
• CPC Class Codes: B41J 2/3357 Surface type resistors

Abstract

A thermal print head includes: a substrate having an obverse surface; a plurality of heat generators arranged on the substrate in a main scanning direction; and a wiring layer provided on the substrate and constituting an energization path to the heat generators. The substrate has a protrusion protruding from the obverse surface and extending in the main scanning direction. The protrusion has a top portion having the largest distance from the obverse surface, and an inclined portion connected to the top portion in a sub-scanning direction. The inclined portion is inclined relative to the obverse surface at a predetermined angle. Each of the plurality of heat generators extends across a boundary between the top portion and the inclined portion. Each of the heat generators is formed on at least a part of the top portion and at least a part of the inclined portion in the sub-scanning direction.

Claims

1. A thermal print head comprising:

a main substrate having an obverse surface;

a resistor layer supported by the main substrate and having a plurality of heat generators arranged in a main scanning direction;

a first wiring layer supported by the main substrate and constituting an energization path to the plurality of heat generators;

at least one driver IC that performs energization control on the plurality of heat generators; and

a flexible wiring substrate having a second wiring layer jointed to the first wiring layer via an anisotropic conductive joint material,

wherein the driver IC is mounted on the flexible wiring substrate.

2. The thermal print head according to claim 1, wherein the first wiring layer includes a plurality of individual electrodes and a common electrode, and the plurality of individual electrodes are electrically connected to the common electrode via the plurality of heat generators.

3. The thermal print head according to claim 2, wherein the flexible wiring substrate has a plurality of individual wires electrically connected to the plurality of individual electrodes, and a common wire electrically connected to the common electrode.

4. The thermal print head according to claim 3, further comprising a pitch changing portion between the main substrate and the driver IC, in which pitches of the plurality of individual wires in the main scanning direction decreases from the main substrate toward the driver IC.

5. The thermal print head according to claim 3, wherein the plurality of individual electrodes comprise a plurality of individual pads facing in a thickness direction of the main substrate, and the plurality of individual wires of the flexible wiring substrate are joined to the plurality of individual pads via the anisotropic conductive joint material.

6. The thermal print head according to claim 5, wherein the common electrode includes a common pad facing in the thickness direction of the main substrate, and the common wire of the flexible wiring substrate is joined to the common pad via the anisotropic conductive joint material.

7. The thermal print head according to claim 3, wherein each of the plurality of individual electrodes comprise an individual end surface exposed in a sub-scanning direction, and the plurality of individual wires of the flexible wiring substrate are joined to the plurality of individual end surfaces via the anisotropic conductive joint material.

8. The thermal print head according to claim 7, wherein the plurality of individual electrodes comprise individual protrusions interposed between the individual end surfaces and the anisotropic conductive joint material, the individual protrusions protruding from the individual end surfaces in the sub-scanning direction.

9. The thermal print head according to claim 7, wherein the common electrode includes a common end surface exposed in the sub-scanning direction, and the common wire of the flexible wiring substrate is connected to the common end surface via the anisotropic conductive joint material.

10. The thermal print head according to claim 9, wherein the common electrode includes a common protrusion interposed between the common end surface and the anisotropic conductive joint material, the common protrusion protruding from the common end surface in the sub-scanning direction.

11. The thermal print head according to claim 3, wherein the flexible wiring substrate includes a fixed portion fixed to the obverse surface of the main substrate.

12. The thermal print head according to claim 3, wherein the flexible wiring substrate includes a mount portion to which the driver IC is joined, and the mount portion extends along a direction intersecting the obverse surface.

13. The thermal print head according to claim 3, wherein the plurality of individual wires are provided on a layer differing from a layer on which the common wire is provided in the thickness direction of the flexible wiring substrate.

14. The thermal print head according to claim 1, wherein the main substrate is made of Si.

15. The thermal print head according to claim 14, wherein the main substrate includes a substrate portion extending in the main scanning direction and protruding from the obverse surface.

16. The thermal print head according to claim 15, wherein the plurality of heat generators are provided on the substrate protrusion.

17. The thermal print head according to claim 1, further comprising an additional wiring substrate, wherein the additional flexible wiring substrate includes a third wiring layer electrically connected to the second wiring layer.

18. The thermal print head according to claim 1, wherein the resistor layer is made of a resistor material provided by thin-film forming, and the first wiring layer is made of a metal provided by thin-film forming.

19. The thermal print head according to claim 1, wherein the resistor layer is made of a baked paste containing a resistor material, and the first wiring layer is made of a baked conductive paste.