A method of manufacturing a thermal print head structure includes the following steps. A glaze layer, a heating resistor layer, an electrode layer and a photoresist layer are sequentially coated on a substrate, in which the photoresist layer has an arc ridge portion in accordance with the formation of the glaze layer. The arc ridge portion of the photoresist layer is partially removed such that a sunken portion is formed on the arc ridge portion. The photoresist layer is fully thinned to remove a bottom of the sunken portion, so that a local position of the electrode layer is revealed. The local position of the electrode layer is etched so that the heating resistor layer is partially revealed outwardly. The photoresist layer is removed from the electrode layer. A protective layer is formed on the electrode layer, the heating resistor layer, and the substrate.

A thermal head of the present disclosure includes a substrate 7, a heat generating unit 9, an electrode, a covering layer 27, and a covering member 29. The heat generating unit 9 is positioned above the substrate 7. The electrode is positioned above the substrate and connected to the heat generating unit 9. The covering layer 27 covers at least a part of the electrode when viewed in plan. The covering member 29 is positioned on the covering layer 27. The covering layer 27 has an upper surface 27a and a lateral surface 27b that is positioned on a side of the heat generating unit 9. An arithmetic-average surface roughness Ra of the lateral surface 27b is higher than an arithmetic-average surface roughness Ra of the upper surface 27a.

A thermal head includes a substrate, a glaze layer, and a reinforced conductor layer. The glaze includes a first glaze and a second glaze. The first glaze extends in a predetermined direction on the surface of the substrate. The second glaze is spaced part from the first glaze to one side in a direction perpendicular to the predetermined direction on the surface of the substrate. The reinforced conductor layer includes a lateral side part. The lateral side part extends on the surface of the substrate from the first glaze side to the second glaze side and is partially located on the second glaze. An edge part on the first glaze side in the second glaze includes a cutout portion cut out toward the one side in the direction perpendicular to the predetermined direction. The lateral side part passes through the cutout portion.

A recording element substrate includes a substrate, a plurality of energy generating elements arranged on the substrate to form an element row, a plurality of supply ports arranged along the element row to form a supply port row, and a plurality of supply paths extending from the plurality of supply ports along the thickness direction of the substrate, wherein a plurality of beam portions disposed between adjacent supply ports in the direction of the supply port row has a plurality of conductor layers in which a conductor layer including a power supply conductor connected to the energy generating elements and a conductor layer including a ground conductor connected to the energy generating elements, are stacked along the thickness direction of the substrate, and wherein at least one of the plurality of conductor layers is occupied by one power supply conductor or one ground conductor.

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.

A thermal printhead includes a substrate, a resistor layer with heat generation portions supported by the substrate and aligned in a primary scanning direction, a wiring layer supported by the substrate to form a conductive path to the heat generation portions, an insulating layer interposed between the substrate and the resistor layer, and a reflection layer located opposite to the heat generation portions with respect to the insulating layer. The reflection layer overlaps with the heat generation portions as viewed in a thickness direction of the heat generation portions and has a greater heat reflectivity than the insulating layer.

A liquid ejection head capable of reducing the thickness of the protective layer as compared to the traditional technique and efficiently transferring the heat energy generated by the heating resistance element to a droplet such as ink and a method of manufacturing the liquid ejection head provide. To achieve this, a power supply wiring are provided in the same layer below the heating resistance element.

A liquid discharge head includes a recording element substrate. The recording element substrate includes a discharge aperture forming member defining a discharge aperture from which a liquid is discharged and a substrate having a pressure generating element that pressurizes the liquid so as to discharge the liquid. The liquid discharge head also includes a cover member that defines an opening through which the discharge aperture is exposed. The cover member is disposed on a side of the recording element substrate on which the discharge aperture is formed. In the liquid discharge head, the recording element substrate further includes an electrode disposed on a side of the substrate on which the discharge aperture forming member is formed and an insulation member that covers the electrode. In addition, the insulation member is covered by the cover member.

A liquid ejection head includes a recording element substrate including an ejection port member including a liquid ejection port, an electrical wiring layer including a pressure generating element that pressurizes the liquid to eject the liquid and an electrically connecting part connected to the pressure generating element to supply power for driving the pressure generating element to the pressure generating element, and a silicon substrate having the ejection port member and the electrical wiring layer. The silicon substrate includes a through-hole passing through the silicon substrate to expose the electrically connecting part. An outer shape of an opening of the through-hole on the back side of the silicon substrate has no side parallel to direction [110] of the silicon substrate or has a side parallel to the direction [110]. The side has a length equal to or less than half an entire length of the through-hole in the direction [110].

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.