JP5052415B2 - Recording head and recording apparatus having the same - Google Patents

Description

  The present invention relates to a recording head and a recording apparatus including the recording head.

  As a printer such as a facsimile or a register, a thermal printer including a thermal head and a platen roller is used. As a thermal head mounted on such a thermal printer, a head substrate, a plurality of heating elements arranged on the head substrate, and a heat radiating body on which the head substrate is placed and which dissipates heat generated by the heating elements. There is something to have. The platen roller has a function of pressing the recording medium against the heating element. In the thermal printer having such a configuration, the heat generating element generates heat according to a desired image, and the heat generated by the heat generating element is applied to the recording medium by pressing the recording medium evenly on the heating element with a platen roller. To communicate well. Desired image formation on the recording medium is performed by repeating this process.

Some thermal heads mounted on such a thermal printer are fixed to the thermal printer by inserting a short pin into a shaft provided on a support. Such a thermal head is disclosed in Patent Document 1, for example.
JP 7-329396 A

  However, since the thermal head disclosed in Patent Document 1 is provided with a circular groove into which the shaft is inserted into the support body, the circular groove is provided on the side where the circular groove is provided. The rate of thermal expansion of the support was different between the non-exposed side and the support was sometimes warped by the heat generated by the heating element. This warping of the support tends to occur at the start of driving of the thermal head in which the temperature difference between the side where the circular groove is provided and the side where the circular groove is not provided becomes large. When the support is warped, the substrate or the heating element placed on the support may be warped. When the heat generating element is warped in this way, the pressing force of the platen roller varies, and the heat generated by the heat generating element may not be transmitted well.

  The present invention has been conceived under such circumstances, and an object thereof is to provide a recording head capable of forming a good image and a recording apparatus including the recording head.

  The recording head of the present invention includes a substantially rectangular substrate in plan view, a plurality of heating elements arranged on one main surface along one long side of the substrate, and the other main surface of the substrate A first reference surface extending along the other long side of the substrate, the heat sink being depressed toward the heating element side from the first reference surface, and A first recess that extends along the other long side, a second reference surface that extends along one long side of the substrate, a recess that is recessed toward the heating element from the second reference surface, and A second indentation extending along the long side, the first indentation having fitting portions at both ends thereof, and the volume of the second indentation compared to the volume of the first indentation. It is small.

  In the recording head of the present invention, it is preferable that the depth of the second recess portion from the second reference surface is shallower than the depth of the first recess portion from the first reference surface.

  In the recording head according to the aspect of the invention, it is preferable that the heating element is located between the first dent portion and the second dent portion in a plan view.

  In the recording head according to the aspect of the invention, it is preferable that the heating element has a shorter distance from the second reference surface than the distance from the first reference surface in a plan view.

  The recording head of the present invention further includes a screw that is screwed into the fitting portion, and the screw is preferably a self-tapping screw. The heat radiating body of the recording head having this configuration is further recessed from at least the inner peripheral surface of the fitting portion of the first recess portion, and has a third recess portion facing the opening portion of the first recess portion. More preferably.

  In the recording head of the present invention, it is preferable that the first recess has an inner circumferential surface having a substantially arc shape. In the recording head of this configuration, it is preferable that the inner peripheral surface of the second depression is substantially arc-shaped, and the curvature of the second depression is larger than the curvature of the first depression.

  The heat radiating body of the recording head of the present invention has a substantially rectangular parallelepiped main body, and the minimum thickness between the upper surface of the main body contacting the substrate and the inner peripheral surface of the first recess is small. It is preferable that it is thicker than the minimum thickness between the lower surface of the main body and the inner peripheral surface of the first recess.

  The recording apparatus of the present invention includes the recording head and a transport unit that transports a recording medium.

  The recording head of the present invention includes a substantially rectangular substrate in plan view, a plurality of heating elements arranged on one main surface along one long side of the substrate, and the other main surface of the substrate. A first reference surface that extends along the other long side of the substrate, and the other long side that is recessed toward the heating element from the first reference surface. A first recess extending along the first reference line, a second reference surface extending along one long side, and a second reference surface extending from the second reference surface toward the heating element side and extending along one long side. 2 dents, the first dents are fitted at both ends, the first dents are fitted at both ends, and the volume of the second dent is larger than the volume of the first dent. Small. Therefore, in the recording head of the present invention, the rate of thermal expansion of the heat radiating body can be made closer to the first reference surface side and the second reference surface side, for example, even in a transient state where the temperature of the heat radiating member rises. It is possible to reduce the degree of warping that occurs in the case. Therefore, in the recording head of the present invention, the degree of warping generated between the substrate and the heating element placed on the heat radiating body can be reduced, and as a result, a good image can be formed.

  In the recording head of the present invention, when the depth from the second reference surface of the second depression is shallower than the depth from the first reference plane of the first depression, the first depression and the second depression It is possible to reduce the decrease in the heat capacity between the two. For this reason, in the recording head of this configuration, the heat generated by the heating element can be satisfactorily transmitted to the radiator.

  In the recording head of the present invention, when the heating element is located between the first depression and the second depression in a plan view, the heat capacity of the radiator located under the heating element is not reduced. That's it. For this reason, in the recording head of this configuration, the heat generated by the heating element can be satisfactorily transmitted to the radiator. Further, in the recording head of this configuration, for example, even when the recording medium is pressed against the heat generating element, it can be favorably supported by the heat radiating body.

  In the recording head of the present invention, when the heating element has a shorter distance from the second reference surface than the first reference surface in a plan view, the heat capacity of the radiator located below the heating element is reduced. For example, even when a short one is inserted in the insertion portion, it is possible to reduce the occurrence of variation in the transmission of heat generated by the heating element between the center portion and the end portion. For this reason, in the recording head of this configuration, the heat generated by the heating element can be satisfactorily transmitted to the radiator.

  In the recording head of the present invention, the recording head further includes a screw that is screwed into the insertion portion, and when the screw is a self-tapping screw, chips are generated when a screw groove that fits into the screw thread is formed. Can be reduced. Therefore, in the recording head of this configuration, it is possible to reduce the occurrence of scratches on the protective film formed on the heat generating element or the short circuit of the heat generating element due to the generated chips. Further, in the recording head of the present configuration, the heat radiating body is further recessed from at least the inner peripheral surface of the insertion portion of the first recess portion, and has a third recess portion facing the opening portion of the first recess portion. In this case, the symmetry of the force acting when the tapping screw is screwed can be increased, and for example, the bending of the screw insertion direction can be reduced.

  In the recording head of the present invention, when the inner peripheral surface of the first recess is substantially arcuate, the stress due to the thermal expansion of the radiator can be well dispersed and the bending strength can be increased. Therefore, in the recording head of this configuration, it is possible to further reduce the degree of warpage generated in the heat radiator. Further, the recording head of this configuration can be mounted satisfactorily even when, for example, a screw is screwed into the insertion portion. In the recording head of this configuration, when the inner peripheral surface of the second depression is substantially arc-shaped and the curvature of the second depression is larger than the curvature of the first depression, the stress due to the thermal expansion of the radiator is improved. Can be dispersed. Therefore, in the recording head of this configuration, it is possible to further reduce the degree of warpage generated in the heat radiator.

  In the recording head of the present invention, the heat radiating body has a substantially rectangular parallelepiped main body, and the lower surface where the minimum thickness between the upper surface contacting the substrate and the inner peripheral surface of the first recess is the upper surface. When the thickness of the heat sink is thicker than the minimum thickness of the first recess and the inner peripheral surface of the first recess, the heat generated by the heat generating element can be transferred to the heat sink even when the overall thickness of the heat sink is reduced. Can be supported.

  The recording apparatus according to the present invention includes a recording head. Therefore, this recording apparatus can enjoy the effects of the recording head. Therefore, this recording apparatus can form a good image.

<Recording head>
FIG. 1 is a diagram showing a schematic configuration of a thermal head X which is an example of an embodiment of a recording head of the present invention, where (a) is a plan view thereof and (b) is a side view thereof. Here, the “plan view” refers to a view viewed in the direction of the arrow D6, and the “side view” refers to a view viewed in the direction of the arrow D2.

  2 is an enlarged view of a main part of the thermal head X shown in FIG. 1, (a) is a plan view, and (b) is a cross-sectional view taken along the line IIb-IIb shown in (a). .

  The thermal head X includes a substrate 10, a heat storage layer 20, a resistor layer 30, a conductive layer 40, a protective layer 50, a drive IC 60, and a heat radiator 70.

  The substrate 10 has a function of supporting the heat storage layer 20, the resistor layer 30, the conductive layer 40, the protective layer 50, and the drive IC 60. The substrate 10 is configured in a substantially rectangular shape extending in the arrow directions D1 and D2 in plan view. In the present embodiment, the directions in which the first long side 10a of the substrate 10 extends in plan view are indicated by arrow directions D1 and D2.

  The heat storage layer 20 has a function of temporarily storing a part of heat generated in a heating element H described later of the resistor layer 30. That is, the heat storage layer 20 plays a role of improving the thermal response characteristics of the thermal head X by shortening the time required to raise the temperature of the heating element H. The heat storage layer 20 is located on one main surface 10c of the substrate 10 and is configured in a strip shape extending in the arrow directions D1 and D2. The heat storage layer 20 has a substantially semi-elliptical cross section in the arrow directions D3 and D4 orthogonal to the arrow directions D1 and D2.

  The resistor layer 30 is connected to the conductive layer 40. A part of the resistor layer 30 is located on the heat storage layer 20. In the present embodiment, a portion of the resistor layer 30 to which a voltage is applied from the conductive layer 40 where the conductor layer 40 is not formed functions as the heating element H.

  The heating element H generates heat when a voltage is applied from the conductive layer 40. The heat generating element H is configured such that the heat generation temperature due to voltage application from the conductive layer 40 is in the range of 200 ° C. or higher and 450 ° C. or lower, for example. The heat generating elements H are located above the heat storage layer 20 and are arranged along the first long side 10a, and consequently the arrow directions D1 and D2. In the present embodiment, the arrangement direction of the heating elements H is the main scanning direction of the thermal head X.

  The conductive layer 40 includes a first conductive layer 41 and a second conductive layer 42. The conductive layer 40 is located on the resistor layer 30.

  The first conductive layer 41 has one end connected to one end of each of the plurality of heating elements H. The first conductive layer 41 has each other end connected to the drive IC 60. The first conductive layer 41 is located on the side of the heating element H in the direction of arrow D4.

  The end of the second conductive layer 42 is electrically connected to the other ends of the plurality of heating elements H and a power source (not shown). The second conductive layer 42 is located on the arrow D3 direction side of the heating element H.

  The protective layer 50 has a function of protecting the heat generating element H and the conductive layer 40. The protective layer 50 is formed so as to cover the heating element H and the conductive layer 40.

  The drive IC 60 has a function of controlling the power supply state of the plurality of heating elements H. The drive IC 60 is electrically connected to the other end portion of the first conductive layer 41. With such a configuration, the heating element H can be selectively heated. An external connection member 61 is electrically connected to the drive IC 60.

  The external connection member 61 has a function of supplying an electrical signal for driving the heating element H. Examples of the external connection member 61 include a combination of a flexible cable 61a and a connector 62b.

  3 is an enlarged view of the heat radiating body 70 shown in FIG. 1, (a) is a cross-sectional view along arrow directions D3 and D4, and (b) is IIIb-IIIb shown in FIG. It is sectional drawing along a line.

  The radiator 70 has a function of radiating the heat generated by the heat generating element H to the outside. The heat radiator 70 also has a function as a support base material for the substrate 10, and the main surface 70 a faces the other main surface of the substrate 10. Further, in the heat radiating body 70, the first side surface 70b on the arrow D4 direction side extends along the second long side 10b of the substrate 10, and thus along the arrow directions D1 and D2. In addition, in the heat dissipating body 70, the second side surface 70c on the arrow D3 direction side extends along the first long side 10a, and thus the arrow directions D1 and D2. Examples of the material for forming such a heat radiating body 70 include a metal material such as copper and aluminum, and a material obtained by mixing a thermosetting or ultraviolet curable resin material with a material having high thermal conductivity. Here, the material having a high thermal conductivity includes a material having a higher thermal conductivity than the material constituting the substrate 10, and examples thereof include a metal material and a carbon nanotube.

  The heat radiating body 70 of the present embodiment further includes a first dent portion 701 that extends along the arrow directions D1 and D2 and is recessed in the arrow D3 direction on the first side face 70b. Moreover, the heat radiating body 70 of the present embodiment further has a second dent portion 702 that extends along the arrow directions D1 and D2 and is recessed in the arrow D4 direction on the second side surface 70c. Furthermore, the heat radiating body 70 of the present embodiment has a protruding portion 703 that protrudes in the direction of arrow D5 from the main surface 70a.

The first depression 701 includes a first arcuate surface 701a, a second arcuate surface 701b, and a third depression 7011. The first recess 701 is substantially constant a depth _{h 1} is over in the direction of the arrow D1, D2. The first arc-shaped surface 701a and the second arc-shaped surface 701b are located facing each other and are formed in a substantially arc shape. The third depression 7011 faces the opening 701e of the first depression 701. The third recess 7011 is recessed from the first arcuate surface 701a and the second arcuate surface 701b, and the first arcuate surface 701a and the second arcuate surface 701b are separated from each other.

The second recess 702 includes a third arcuate surface 702a. The first recess 702 is substantially constant a depth _{h 2} is over in the direction of the arrow D1, D2. Further, the depth h ₂ of the second depression 702 is configured to be smaller than the depth h ₁ of the first depression 701. Further, the second depression 702 is configured such that its volume is smaller than the volume of the first depression 701. Here, the “volume of the depression” means the volume of the space defined by the depression. The “volume of the recess” in the present embodiment is a volume of a space that is recessed from the first side surface 70 b and surrounded by the first recess 701, or is recessed from the first side surface 70 c and is surrounded by the second recess 702. It corresponds to the volume of the space. In the present embodiment, the first dent portion 701 and the second dent portion 702 are formed along the arrow directions D1 and D2, and the depths h ₁ and h ₂ are substantially constant. The “volume” corresponds to the cross-sectional area in the planes indicated by arrows D3, D4-arrows D5, D6. The third arcuate surface 702a of the second recess 702 is configured such that the curvature is smaller than the curvatures of the first arcuate surface 701a and the second arcuate surface 701b.

In the present embodiment, the heating element H is located on the region 70d between the first dent 70b and the second dent 70d in plan view. Furthermore, the heating element H of this embodiment, whereas in a plan view of the major surface 10c, the distance d ₁ from the first long side 70b is longer than the distance d ₂ from the second long side 70c.

  Furthermore, the heat radiating body 70 of this embodiment further has a screw 71. Each of the first arc-shaped surface 701a and the second arc-shaped surface 701b is provided with a thread groove that fits the thread of the screw 71 at both ends in the arrow directions D1 and D2, and the first threaded portion 701c and the second arc-shaped surface 701b. Two screwing portions 701d are configured.

  The projecting portion 703 has a function of using the external connection members 61a and 61b as a support portion.

  The screw 71 has a function of fixing the thermal head X. One of the screws 71 is inserted from the direction of the arrow D1 and is screwed to the first screwing portion 701c. The other of the screws is inserted from the direction of the arrow D2 and is screwed to the second screwing portion 701d. In the present embodiment, the radiator 70 is fixed to the flange 72 by screws 71, and the thermal head X is mounted on the thermal printer via the flange 72. Various types of screws 71 may be used, and the screws 71 of the present embodiment are constituted by self-tapping screws. Note that the screws 71 and the flanges 72 are omitted except for those shown in FIG.

  The thermal head X includes a substantially rectangular substrate 10 in plan view, a plurality of heating elements H arranged on one main surface 10c along the first long side 10a of the substrate 10, and the other main surface of the substrate 10. And the heat sink 70 is recessed in the direction of the arrow D3 from the first side face 70b extending along the second long side 10b of the substrate 10 and the first side face 70b, and A first recess 701 extending along the second long side 10b, a second side surface 70c extending along the first long side 10a, and a recess on the arrow D4 direction side from the second side surface 70c and the first long side 10a And the second dent portion 702 extends along the first dent portion 701. The first dent portion 701 includes a first screwed portion 701c and a second screwed portion 701d at both ends in the arrow directions D1 and D2, and a second dent portion. The volume of 702 is that of the first recess 701 Smaller than that of the product. Therefore, in the thermal head X, the rate of thermal expansion of the radiator 70 can be made closer to the first side surface 70b side and the second side surface 70c side, and for example, even in a transient state where the temperature of the radiator body rises. It is possible to reduce the degree of warping that occurs in the case. Therefore, in the thermal head X, it is possible to reduce the degree of warping that occurs between the substrate 10 placed on the heat radiating body 70 and the heating element H, and it is possible to form a good image.

In the thermal head X, since the depth _{h 2} with respect to the second side of the second recess 702 is shallow than the depth _{h 1} to the first side surface 70b of the first recess portion 701, a first recessed portion 701 second recess It can reduce that the heat capacity between the part 702 becomes small. Therefore, in the thermal head X, the heat generated by the heating element H can be transmitted to the heat radiating body 70 satisfactorily.

  In the thermal head X, the heat generating element H is located on the region 70d between the first hollow portion 701 and the second hollow portion 702 in plan view. It is not necessary to reduce the heat capacity. Therefore, in the thermal head X, the heat generated by the heating element H can be transmitted to the heat radiating body 70 satisfactorily. Further, in the thermal head X, for example, even when the recording medium is pressed against the heating element H, it can be favorably supported by the radiator 70.

In the thermal head X, the heating elements H are, in a plan view, the distance d ₂ is short from the second side surface 70c than the distance d ₁ from the first side surface 70b, located beneath the heating element H radiator The heat capacity of the body 70 is further increased, and even when, for example, the screw 71 is screwed into the first screwing portion 70c and the second screwing portion 701d, the transmission of heat generated by the heating element H varies between the center portion and the end portion. Can be reduced. Therefore, in the thermal head X, the heat generated by the heating element H can be transmitted to the heat radiating body 70 satisfactorily.

  The thermal head X further includes a screw 71 to be screwed into the first screwing portion 70c and the second screwing portion 701d. Since the screw 71 is a self-tapping screw, it fits into the thread of the screw 70. It is possible to reduce the occurrence of chips when forming the screw grooves to be joined. Therefore, in the thermal head X, it is possible to reduce, for example, damage to the protective film 50 or a short circuit of the electric circuit due to the generated chips. Further, in the thermal head X, the radiator 70 is recessed from the first recess 701 and has a third recess 7011 facing the opening of the first recess 701, so that a tapping screw is screwed. For example, it is possible to increase the symmetry of the force acting upon the bending, and to reduce the bending of the insertion direction of the screw 71, for example.

  In the thermal head X, since the first arc-shaped surface 701a and the second arc-shaped surface 701b of the first recess 701 are substantially arc-shaped, the stress due to the thermal expansion of the heat radiating body 70 can be well dispersed and the bending strength can be increased. it can. Therefore, in the thermal head X, the degree of warpage generated in the heat radiating body 70 can be further reduced. Further, the thermal head X can be favorably attached when screws are screwed onto the first screwing portion 70c and the second screwing portion 701d, for example.

  In the thermal head X, the third arcuate surface 702a of the second depression 702 is substantially arc-shaped, and the curvature thereof is larger than the curvature of the first depression 701, so that the stress due to the thermal expansion of the radiator 70 can be dispersed well. The bending strength can be increased. Therefore, in the thermal head X, the degree of warpage generated in the heat radiating body 70 can be further reduced.

<Recording device>
FIG. 4 is a diagram showing a schematic configuration of a thermal printer Y which is an example of an embodiment of the recording apparatus of the present invention.

  The thermal printer Y includes a thermal head X, a transport mechanism 80, and a drive mechanism 90. The thermal printer Y has a function of performing printing on the recording medium P conveyed in the direction of arrow D3. Here, as the recording medium P, a thermal paper or a thermal film whose surface density varies by heating, and an ink film and a transfer paper on which an image is formed by transferring an ink component melted by heat conduction are used.

  The transport mechanism 80 includes a platen roller 81 and transport rollers 82, 83, 84, and 85.

  The platen roller 81 has a function of pressing the recording medium P against the protective layer 50 positioned on the heating element H of the thermal head X. The platen roller 81 is rotatably supported in contact with the protective layer 50 located on the heating element H.

  The conveyance roller 82 has a function of conveying the recording medium P. That is, the transport rollers 82, 83, 84, and 85 serve to supply the recording medium P between the heating element H and the platen roller 81 and to pull out the recording medium P from between the heating element H and the platen roller 81. It is what you bear.

  The drive mechanism 90 has a function of supplying image information to the drive IC 60. That is, the drive mechanism 90 plays a role of supplying image information for selectively driving the heat generating element H to the drive IC 60 via the external connection member 61.

  The thermal printer Y includes a thermal printer X1. Therefore, the thermal printer Y can enjoy the effects of the thermal head X. Therefore, the thermal printer Y can form a good image.

  While specific embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  In the present embodiment, the thermal head X is described as an example of the recording head, but the present invention is not limited to the thermal head. For example, even when the configuration of the present invention is adopted in an ink jet head, the degree of warpage generated in the heat dissipation element due to the heat generated by the heat generation element is reduced, and as a result, the warpage generated in the substrate and the heat generation element placed on the heat dissipation element is also reduced. The degree can be reduced.

In the heat dissipation body 70 of the present embodiment, the thickness between the first recess 701 and the main surface 70a is equal to the thickness between the first recess 701 and the other main surface 70e, but is not limited to such a configuration. For example, if thicker than _{t 2} between the thickness _{t 1} between the first recessed portion 701A and the main surface 70Aa as shown in FIG. 5 of the first recess 701A and the other main surface 70ae, heat radiator 70A total thickness with satisfactorily transmitted to the heat radiating body 70A of the heat generated by the heating element H even when the small t _3, it is possible to satisfactorily support the substrate 10. Furthermore, in this case, it causes the deformation of the heat radiating body 70A due to thermal stress by reducing the thickness _{t 2} between the first recessed portion 701A and the other main surface 70ae, between the first recessed portion 701A and the main surface 70Aa The deformation of the main surface 70Aa can be reduced as a result of the deformation of the main surface 70Aa. Further, as shown in FIG. 5, in the radiator 70A, even if the minimum thickness between the second recess 702A and the main surface 70Aa is larger than the minimum thickness between the second recess 702A and the other main surface 70Ae. Good.

  In the present embodiment, the first screw portion 701c and the second screw portion 701d are provided in the first recess portion 701 of the heat radiating body 70, but the present invention is not limited to such a structure. For example, a fitting portion into which a rod-like material such as a shaft is fitted may be provided.

  You may provide piping for cooling in the 1st hollow part 701 and the 2nd hollow part 702 of this embodiment.

2A and 2B are diagrams illustrating a schematic configuration of a thermal head that is an example of an embodiment of a recording head of the present invention, in which FIG. 1A is a plan view thereof, and FIG. It is a principal part enlarged view of the thermal head shown in FIG. 1, (a) is a top view, (b) is sectional drawing along the IIb-IIb line | wire shown to (a). It is an enlarged view of the heat radiator shown in FIG. 1, (a) is sectional drawing along arrow direction D3, D4, (b) is a cross section along the IIIb-IIIb line | wire shown in FIG. 3 (a). FIG. 1 is an overall view showing a schematic configuration of a thermal printer which is an example of an embodiment of a recording apparatus of the present invention. It is a figure which shows the modification of the heat radiator shown in FIG.

Explanation of symbols

X thermal head Y thermal printer 10 substrate 10a first long side 10b second long side 10c one main surface 20 heat storage layer 30 resistor layer 40 conductive layer 41 first conductive layer 42 second conductive layer 50 protective layer 60 driving IC
61a, 61b External connection member 70 Radiator 70a Main surface (upper surface)
70b First side surface (first reference surface)
70c Second side (second reference plane)
70e The other main surface (lower surface)
701 First depression 701a First arcuate surface 701b Second arcuate surface 701c First screwing portion 701d Second screwing portion 701e Opening 7011 Third depression 702 Second depression 702a Third arcuate surface 703 Protrusion 80 Transport Means 81 Platen rollers 82, 83, 84, 85 Conveying roller 90 Driving means H Heating element P Recording medium

Claims (10)

A substantially rectangular substrate in plan view, a plurality of heating elements arranged on one main surface along one long side of the substrate, and a radiator provided on the other main surface of the substrate And comprising
The heat radiator has a first reference surface extending along the other long side of the substrate, and a first recess portion that is recessed toward the heat generating element from the first reference surface and extends along the other long side. And a second reference surface extending along one long side of the substrate, and a second recess portion that is recessed toward the heat generating element from the second reference surface and extends along the one long side. And
The recording head according to claim 1, wherein the first dent portion has fitting portions at both ends thereof, and a volume of the second dent portion is smaller than a volume of the first dent portion.   2. The recording head according to claim 1, wherein a depth of the second recess portion from the second reference surface is shallower than a depth of the first recess portion from the first reference surface.   3. The recording head according to claim 1, wherein the heating element is located between the first dent and the second dent in a plan view.   4. The recording head according to claim 1, wherein the heating element has a shorter distance from the second reference surface than a distance from the first reference surface in a plan view. 5. A screw that is screwed into the fitting portion;
The recording head according to claim 1, wherein the screw is a self-tapping screw.   The heat radiator is further recessed at least from the inner peripheral surface of the fitting portion of the first recess portion, and has a third recess portion facing the opening portion of the first recess portion. The recording head according to claim 5.   The recording head according to claim 1, wherein an inner peripheral surface of the first recess is substantially arc-shaped.   8. The recording head according to claim 7, wherein an inner peripheral surface of the second depression is substantially arc-shaped, and a curvature of the second depression is larger than a curvature of the first depression. The radiator has a substantially rectangular parallelepiped main body,
The minimum thickness between the upper surface of the main body portion that contacts the substrate and the inner peripheral surface of the first recess portion is the minimum thickness between the lower surface of the main body portion and the inner peripheral surface of the first recess portion. The recording head according to claim 1, wherein the recording head is thicker than the recording head.   A recording apparatus comprising: the recording head according to claim 1; and a transport unit that transports a recording medium.

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