Patent Description:
Conventionally, various thermal heads have been proposed as printing devices such as facsimile machines and video printers. For example, there is known a thermal head in which a head substrate and a wiring board being in contact with each other are connected by wires and sealed with an insulating resin member. Further, in order to reduce the generation of air bubbles at the time of curing the resin member, there is disclosed a structure in which portions other than both end portions on a contact side of the wiring board in contact with the head substrate are cut off (see Patent Document <NUM>, for example).

Patent Document <NUM>: <CIT>
<CIT> discloses a thermal head including heat generating members, a drive IC, pads and interconnection lines which are all disposed on a substrate, wherein the pads are arranged in a first direction and constitute first pad groups and second pad groups constituted by the pads that constitute the first pad groups, and wherein the second pad groups are arranged in the first direction so as to be shifted from each other in a second direction that differs from the first direction. <CIT> discloses a thermal print head including a drive circuit, a circuit board, a sealing material, and an air gap, wherein the drive circuit is provided on a first ceramic plate, wherein the circuit board is provided on a second ceramic plate, and wherein the sealing material is provided to cover the drive circuit, a part of the circuit board and the first ceramic plate, the thermal print head further including an air gap provided right below a region where the circuit board projects.

The present invention provides a thermal head according to claim <NUM> and a thermal printer according to claim <NUM>. Preferred embodiments are described in the dependent claims.

Embodiments of a thermal head and a thermal printer disclosed in the present application will be described below with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments that will be described below.

<FIG> is a perspective view illustrating a configuration of a thermal head <NUM> according to a first embodiment.

The thermal head <NUM> according to the first embodiment includes a head base <NUM>, a wiring board <NUM>, a resin member <NUM>, and a heat dissipation plate <NUM>, as illustrated in <FIG>. The head base <NUM> includes a substrate <NUM>, a heat generating unit <NUM>, a heat storage layer <NUM>, a plurality of individual electrodes <NUM>, and a common electrode <NUM>.

The head base <NUM> has a substantially rectangular parallelepiped shape that is wide in the arrangement direction of the heat generating unit <NUM>. Each member constituting the thermal head <NUM> is provided on a first surface <NUM> that is a front surface of the substrate <NUM>. The head base <NUM> has a function of printing on a recording medium (not illustrated) in accordance with electrical signals supplied from the outside.

The substrate <NUM> has a substantially rectangular parallelepiped shape and is made of an electrically insulating material such as an alumina ceramic or a semiconductor material such as monocrystalline silicon.

The heat storage layer <NUM> is located on the first surface <NUM> of the substrate <NUM> along a longitudinal direction (hereinafter may be referred to as a "first direction") of the substrate <NUM>. The heat storage layer <NUM> is made of a material such as a glass having low thermal conductivity and has a function of temporarily storing part of heat generated by the heat generating unit <NUM>. Thus, the time required to raise the temperature of the heat generating unit <NUM> can be shortened, and the heat storage layer <NUM> functions to enhance the thermal response characteristics of the thermal head <NUM>. The heat storage layer <NUM> is formed by, for example, applying a predetermined glass paste, which is obtained by mixing a glass powder with an appropriate organic solvent, onto the first surface <NUM> of the substrate <NUM> by common well-known screen printing or the like, and firing the glass paste.

The heat generating unit <NUM> is located on the heat storage layer <NUM>. A plurality of elements constituting the heat generating unit <NUM> are arranged along the longitudinal direction of the substrate <NUM>. The heat generating unit <NUM> has a function of generating heat in accordance with electrical signals supplied from the outside to print on a recording medium (not illustrated). The plurality of elements constituting the heat generating unit <NUM> are disposed at a density of, for example, <NUM> dpi to <NUM> dpi (dots per inch).

The heat generating unit <NUM> includes an electric resistance layer having a relatively high electric resistance, such as a TaN-based layer, a TaSiO-based layer, a TaSiNO-based layer, a TiSiO-based layer, a TiSiCO-based layer, or a NbSiO-based layer. The electric resistance layer is located between the individual electrode <NUM> and the common electrode <NUM>. When a voltage is applied to the electric resistance layer, the electric resistance layer generates heat by Joule heating.

The plurality of individual electrodes <NUM> are located side by side on one side of the heat generating unit <NUM> on a first surface <NUM> side of the substrate <NUM>. The plurality of individual electrodes <NUM> are individually connected to the elements of the heat generating unit <NUM> one by one. The common electrode <NUM> is located on the first surface <NUM> of the substrate <NUM> so as to surround the remaining three sides of the heat generating unit <NUM>. The common electrode <NUM> is commonly connected to all of the elements of the heat generating unit <NUM>. The individual electrode <NUM> and the common electrode <NUM> are made of, for example, a metal such as Cu or Al. Details of the individual electrode <NUM> and the common electrode <NUM> will be described later.

The wiring board <NUM> has a plate shape that is wide in the arrangement direction of the heat generating unit <NUM>. The wiring board <NUM> is located adjacent to the head base <NUM> on a side where the individual electrode <NUM> of the head base <NUM> is disposed. The wiring board <NUM> is electrically connected to drive ICs (not illustrated) and is electrically connected to the outside via a connector (not illustrated). The wiring board <NUM> is, for example, a rigid printed wiring board having a high rigidity. Details of the drive IC will be described later.

The resin member <NUM> is located from the wiring board <NUM> to the head base <NUM>. The resin member <NUM> is located across the first surface <NUM> of the substrate <NUM> located on a first surface <NUM> which is a front surface of the heat dissipation plate <NUM> and a first surface <NUM> which is a front surface of the wiring board <NUM>, and seals the drive ICs (not illustrated) and the like located on the first surface <NUM>. Details of the resin member <NUM> will be described later.

The heat dissipation plate <NUM> is located on a back surface side of the substrate <NUM> and on a back surface side of the wiring board <NUM>. The heat dissipation plate <NUM> is, for example, a metal plate made of Cu, Al, or stainless steel. The heat dissipation plate <NUM> has a function of dissipating excess heat generated on the substrate <NUM> and on the wiring board <NUM> to the outside.

Next, details of the individual electrode <NUM> and the common electrode <NUM> will be described. <FIG> is a plan view of the head base <NUM> according to the first embodiment. The plurality of individual electrodes <NUM> are located on the first surface <NUM> side of the substrate <NUM>, and is arranged along the arrangement direction of the heat generating unit <NUM>. The individual electrode <NUM> includes one end 14a and the other end 14b. The one end 14a is electrically connected to the element of the heat generating unit <NUM>. The other end 14b is electrically connected to the drive IC (not illustrated) located on the first surface <NUM> (see <FIG>) of the wiring board <NUM> via a wire (not illustrated). Details of the individual electrode <NUM> will be described later.

The common electrode <NUM> electrically connects each element of the heat generating unit <NUM> and the connector (not illustrated). The common electrode <NUM> includes a main wiring portion 15a, sub wiring portions 15b, and lead portions 15c. The main wiring portion 15a extends along one long side 11a of the substrate <NUM>. The sub wiring portions 15b extend along each of one short side 11b and the other short side 11c of the substrate <NUM>. The lead portions 15c individually extend from the main wiring portion 15a toward elements of the heat generating unit <NUM>. The common electrode <NUM> is electrically connected to the connector (not illustrated) located on the wiring board <NUM> via wires (not illustrated) from end portions 15d. The common electrode <NUM> is located so as to surround the remaining three sides of the heat generating unit <NUM> excluding the other long side 11d side of the substrate <NUM> on which the individual electrodes <NUM> are disposed. The long side 11d is located adjacent to the wiring board <NUM>. Note that the individual electrodes <NUM> and the common electrode <NUM> in <FIG> are schematically illustrated as an example and do not necessarily correspond to actual shapes.

Next, a specific configuration of the thermal head <NUM> according to the first embodiment will be further described with reference to <FIG> and <FIG>. <FIG> is a plan view illustrating a main part of the thermal head <NUM> according to the first embodiment. <FIG> is a cross-sectional view illustrating the main part of the thermal head <NUM> according to the first embodiment. In <FIG>, illustration of the resin member <NUM> is omitted.

The thermal head <NUM> includes a plurality of individual electrode groups <NUM>, a plurality of drive ICs <NUM>, a plurality of first wires <NUM>, and a plurality of second wires <NUM>.

Each of the plurality of individual electrode groups <NUM> includes a plurality of individual electrodes <NUM>. Each of the individual electrodes <NUM> belonging to the individual electrode group <NUM> is electrically connected to the corresponding drive IC <NUM> via the first wire <NUM>. The first wire <NUM> is an example of the wire member. In <FIG>, ten individual electrodes <NUM> are belonging to the individual electrode group <NUM>, but the number of the individual electrodes <NUM> is not limited to ten and can be appropriately set.

The plurality of drive ICs <NUM> are located along the first direction that is the arrangement direction of the heat generating unit <NUM> (see <FIG> and <FIG>). Each of the plurality of drive ICs <NUM> is located facing a corresponding individual electrode group <NUM>. The drive IC <NUM> is electrically connected to the other end 14b of the individual electrode <NUM> on the substrate <NUM> via the first wire <NUM>. The drive IC <NUM> is also electrically connected to a terminal (not illustrated) located on the first surface <NUM> of the wiring board <NUM> via the second wire <NUM>.

The drive IC <NUM> receives electrical signals supplied from the outside via the wiring board <NUM> and the second wire <NUM> electrically connected to the wiring board <NUM>. The drive IC <NUM> supplies power to the heat generating unit <NUM> (see <FIG> and <FIG>) in accordance with received electrical signals to selectively cause each element of the heat generating unit <NUM> to generate heat.

The plurality of first wires <NUM> each electrically connect the drive IC <NUM> and the individual electrodes <NUM> belonging to the individual electrode group <NUM> corresponding to the drive IC <NUM>. The plurality of second wires <NUM> electrically connect the drive IC <NUM> and terminals (not illustrated) located on the first surface <NUM> of the wiring board <NUM>. The first wire <NUM> and the second wire <NUM> are bonding wires made of a metal such as Cu, Au, Al, and the like.

An interval P between the first wires <NUM> connected to the individual electrodes <NUM> belonging to the individual electrode group <NUM> may be, for example, <NUM> or less, or particularly <NUM> or more and <NUM> or less. By adjusting the interval P between the first wires <NUM> in this manner, it is possible to downsize the thermal head <NUM> while ensuring a desired insulating property.

The thermal head <NUM> further includes a plurality of recessed portions <NUM>, a contact portion <NUM>, and a connector <NUM>.

The plurality of recessed portions <NUM> are arranged side by side so as to face an end surface <NUM> of the substrate <NUM> on which the long side 11d of the substrate <NUM> is located. Each of the plurality of recessed portions <NUM> is located so as to be sandwiched between the individual electrode group <NUM> on the substrate <NUM> and the drive IC <NUM> on the wiring board <NUM>. The plurality of recessed portions <NUM> are grooves formed by cutting out one end 20a of the wiring board <NUM> located facing the end surface <NUM>. Further, the plurality of recessed portions <NUM> penetrate from the first surface <NUM> of the wiring board <NUM> to a second surface <NUM> that is a back surface of the wiring board <NUM>. In this manner, the plurality of first wires <NUM> connecting the individual electrodes <NUM> and the drive IC <NUM> are located across the recessed portion <NUM>.

The contact portion <NUM> is located between the recessed portions <NUM> adjacent to each other. The contact portion <NUM> is the one end 20a of the wiring board <NUM> that is in contact with the end surface <NUM>. In other words, the recessed portion <NUM> and the contact portion <NUM> are alternately located on the one end 20a of the wiring board <NUM>.

The connector <NUM> is located on the other end 20b side of the wiring board <NUM> located opposite to the one end 20a close to the substrate <NUM>. The connector <NUM> is electrically connected to the wiring board <NUM> and is electrically connected to the outside. A flexible flat cable (not illustrated) electrically connecting the connector <NUM> and the wiring board <NUM> may be located between the connector <NUM> and the wiring board <NUM>.

Here, sealing of the thermal head <NUM> using the resin member <NUM> will be described. The resin member <NUM> covers all the drive ICs <NUM> located on the wiring board <NUM>. The resin member <NUM> is, for example, a silicone resin or an epoxy resin. The resin member <NUM> seals the drive ICs <NUM>, the first wires <NUM>, the second wires <NUM>, and the like in a state in which the first wires <NUM> and the second wires <NUM> are connected to the drive ICs <NUM>. The resin member <NUM> seals all regions illustrated in <FIG>.

The resin member <NUM> is obtained by sealing a predetermined portion using a resin material having fluidity and then curing the resin material. When the first wires <NUM> having a smaller interval P than the second wires <NUM> and the vicinity of the first wires <NUM> are sealed using the resin material, air bubbles are likely to be trapped in the resin material. In addition, some of the trapped air bubbles cannot be completely removed even after curing and may cause a crater-like depression on the surface of the resin member <NUM> or remain inside the resin member <NUM> as voids. The depression or voids generated in the resin member <NUM> as described above may cause performance failure such as an insufficient resistance value, in addition to an appearance defect.

In the thermal head <NUM> according to the first embodiment, the plurality of first wires <NUM> are located across the plurality of recessed portions <NUM> located between the substrate <NUM> and the wiring board <NUM>. First, the resin material for sealing the plurality of first wires <NUM> and the vicinity thereof is accumulated in a space defined by the first surface <NUM> of the heat dissipation plate <NUM>, side surfaces <NUM> to <NUM> of the recessed portion <NUM>, and the end surface <NUM>. Then, the resin material is further accumulated to a predetermined height so as to cover the plurality of first wires <NUM> located on the wiring board <NUM> and on the substrate <NUM> and then cured. When the resin material is accumulated in order from the heat dissipation plate <NUM> side in this manner, air bubbles are less likely to be trapped even when the resin material reach the height of the first wires <NUM>. Thus, in the thermal head <NUM> according to the first embodiment, it is possible to reduce the occurrence of failures due to the sealing using the resin member <NUM> such as entrapment of air bubbles into the resin material in the process of sealing the first wires <NUM> using the resin material and subsequent depression and voids of the resin member <NUM>.

In addition, the thermal head <NUM> according to the first embodiment includes the contact portion <NUM> located between the recessed portions <NUM> adjacent to each other, and the substrate <NUM> and the wiring board <NUM> are in contact with each other at the contact portion <NUM>. Accordingly, the plurality of recessed portions <NUM> in which the resin material is accumulated are located only in areas overlapping in a plan view with the plurality of first wires <NUM> where the entrapment of air bubbles is likely to occur. Thus, according to the thermal head <NUM> according to the first embodiment an increase in the usage amount of the resin member <NUM> can be reduced.

In addition, in the thermal head <NUM> according to the first embodiment, the contact portion <NUM> is located between the drive ICs <NUM> adjacent to each other and all of the recessed portions <NUM> facing the corresponding drive ICs <NUM>. Thus, in the thermal head <NUM> according to the first embodiment, it is possible to uniformly seal all the drive ICs <NUM> and the plurality of first wires <NUM> connected thereto using the resin material, and reduce the occurrence of failures due to the sealing by the resin member <NUM>.

In addition, a length L1 of the recessed portion <NUM> along the first direction along which the plurality of recessed portions <NUM> are arranged can be larger than a width L2 along the first direction of a region R where the plurality of first wires <NUM> are located in a plan view. As a result, even when the recessed portion <NUM> and the plurality of first wires <NUM>, overlapping overlap the region R in a plan view, are sealed, the resin material can be entered from the side of the region R instead of from the plurality of first wires <NUM> where the entrapment of air bubbles is likely to occur. Thus, the thermal head <NUM> according to the first embodiment can reduce the occurrence of failures due to the sealing by the resin member <NUM>.

The length L1 of the recessed portion <NUM> can be smaller than a length L3 of the drive IC <NUM> along the first direction. This makes it possible to suppress an increase in the usage amount of the resin member <NUM>. Further, it is possible to reduce the occurrence of failures such as exposure of the first wire <NUM> from the resin member <NUM>.

Further, a length L4 of the recessed portion <NUM> in a second direction intersecting the first direction may be, for example, <NUM> or more and <NUM> or less, or further <NUM> or more and <NUM> or less. In one example, the length L4 may be <NUM>. When the length L4 is less than <NUM>, it may be difficult for the resin material to enter the recessed portion <NUM>, and appropriate sealing using the resin member <NUM> may not be achieved. On the other hand, when the length L4 exceeds <NUM>, the usage amount of the resin member <NUM> may be increased.

The surface roughness of the side surfaces <NUM> to <NUM> of the recessed portion <NUM> may be larger than the surface roughness of the contact portion <NUM>. As a result, in the contact portion <NUM>, for example, the substrate <NUM> and the wiring board <NUM> can be accurately aligned, the resin material that has entered the recessed portion <NUM> can be less likely to flow out of the recessed portion <NUM>, and appropriate sealing using the resin member <NUM> can be achieved.

Further, the surface roughness of the side surfaces <NUM> to <NUM> of the recessed portions <NUM> may be larger than the surface roughness of the first surface <NUM> of the wiring board <NUM>. As a result, the resin material having flowed to the first surface <NUM> of the wiring board <NUM> can easily enter the recessed portion <NUM>, and the resin material having entered into the recessed portion <NUM> can be less likely to flow out of the recessed portion <NUM>. Thus, appropriate sealing using the resin member <NUM> can be achieved.

Here, the magnitude of the surface roughness of the side surfaces <NUM> to <NUM>, the contact portion <NUM>, and the first surface <NUM> can be determined based on the arithmetic mean roughness Ra and the maximum height roughness Rz, defined in JIS B0633; <NUM>. The arithmetic mean roughness Ra and the maximum height roughness Rz can be measured, for example, by measuring in a sub scanning direction using a contact type or a non-contact type surface roughness meter. For example, when there is no significant difference in values of either of the arithmetic mean roughness Ra or the maximum height roughness Rz, the magnitude of the surface roughness can be determined in accordance with values of the other.

Moreover, the surface roughness of the side surfaces <NUM> to <NUM> is a value obtained by weighted averaging the measured values of the side surfaces <NUM> to <NUM> in accordance with the length L1 of the side surface <NUM> in the first direction and the length L4 of the side surfaces <NUM> and <NUM> in the second direction intersecting the first direction.

The relationship between the length L1 of the recessed portion <NUM> and the length L3 of the drive IC <NUM> along the first direction is not limited to that described above. That is, the length L1 of the recessed portion <NUM> may be larger than the length L3 of the drive IC <NUM>. This makes it possible to reduce the occurrence of failures due to the sealing using the resin member <NUM>.

Next, a thermal printer <NUM> according to the first embodiment will be described with reference to <FIG> is a schematic view of the thermal printer <NUM> according to the first embodiment.

The thermal printer <NUM> according to the first embodiment includes the thermal head <NUM>, a platen roller <NUM>, and a transport mechanism. Note that the thermal head <NUM> is attached to a housing (not illustrated) in a manner such that the arrangement direction of the heat generating unit <NUM> is along a main scanning direction that is a direction orthogonal to a transport direction of a recording paper <NUM> that is a recording medium.

The transport mechanism includes a drive unit (not illustrated) and transport rollers 3a to 3d. The transport mechanism transports the recording paper <NUM> in an arrow direction illustrated in <FIG> onto the heat generating unit <NUM> of the thermal head <NUM>. The drive unit has a function of driving the transport rollers 3a to 3d. The drive unit may include, for example, a motor. The transport rollers 3a to 3d may be made, for example, by covering a shaft body having a cylindrical shape and made of a metal such as stainless steel, using an elastic member made of butadiene rubber or the like.

The platen roller <NUM> presses the recording paper <NUM> onto the heat generating unit <NUM> of the thermal head <NUM>. The platen roller <NUM> is located so as to extend in a direction (the main scanning direction) orthogonal to the transport direction of the recording paper <NUM>, and both end portions are supported and fixed to be rotatable in a state in which the recording paper <NUM> is pressed onto the heat generating unit <NUM>. The platen roller <NUM> may be made, for example, by covering a cylindrical shaft body made of a metal such as stainless steel or the like, with an elastic member made of butadiene rubber or the like.

As illustrated in <FIG>, the thermal printer <NUM> selectively causes respective elements of the heat generating unit <NUM> to generate heat while pressing the recording paper <NUM> onto the heat generating unit <NUM> of the thermal head <NUM> using the platen roller <NUM> and transporting the recording paper <NUM> onto the heat generating unit <NUM> by the transport mechanism. By the series of operations described above, the thermal printer <NUM> performs predetermined printing on the recording paper <NUM>.

<FIG> is a perspective view illustrating a configuration of a thermal head 1A according to a second embodiment.

As illustrated in <FIG>, the thermal head 1A according to the second embodiment differs from the thermal head <NUM> according to the first embodiment in that, in the thermal head 1A, a plurality of recessed portions 21A include bottom surfaces <NUM> so as to be bottomed openings in which a first surface <NUM> side of a wiring board <NUM> is open, while the thermal head <NUM> includes the plurality of recessed portions <NUM> that penetrate through the wiring board <NUM> in a thickness direction.

First, a resin material for sealing a plurality of first wires <NUM> and the vicinity thereof is accumulated in a space defined by the bottom surface <NUM> of the recessed portion 21A, side surfaces <NUM> to <NUM> of the recessed portion <NUM>, and the end surface <NUM> (see <FIG>). Then, the resin material is further accumulated to a predetermined height so as to cover the plurality of first wires <NUM> located on the wiring board <NUM> and on a substrate <NUM> and then cured. Thus, in the thermal head 1A according to the second embodiment, an increase in the usage amount of the resin member <NUM> can be further reduced as compared to the thermal head <NUM> including the plurality of recessed portions <NUM> that penetrate through the wiring board <NUM> in the thickness direction.

<FIG> is a plan view illustrating a main part of a thermal head 1B according to a third embodiment. <FIG> is a cross-sectional view illustrating the main part of the thermal head 1B according to the third embodiment.

As illustrated in <FIG> and <FIG>, the thermal head 1B according to the third embodiment differs from the thermal heads <NUM> and 1A in that a plurality of recessed portions <NUM> and a contact portion <NUM> are located on an end surface <NUM> side of a substrate <NUM>.

The plurality of recessed portions <NUM> are located so as to face one end 20a of a wiring board <NUM>. The plurality of recessed portions <NUM> are grooves that penetrate from a first surface <NUM> to a second surface <NUM> of the substrate <NUM> so as to cut out the end surface <NUM> of the substrate <NUM> located facing the one end 20a.

In addition, the contact portion <NUM> is located between the recessed portions <NUM> adjacent to each other. The contact portion <NUM> is the end surface <NUM> of the substrate <NUM> that is in contact with the one end 20a of the wiring board <NUM>. That is, the recessed portion <NUM> and the contact portion <NUM> are alternately located on the end surface <NUM> of the substrate <NUM>.

First, a resin material for sealing a plurality of first wires <NUM> and the vicinity thereof is accumulated in a space defined by a first surface <NUM> of a heat dissipation plate <NUM>, the recessed portion <NUM>, and the one end 20a. Then, the resin material is further accumulated to a predetermined height so as to cover the plurality of first wires <NUM> located on the wiring board <NUM> and on the substrate <NUM> and then cured. Thus, in the thermal head 1B according to the third embodiment, it is possible to reduce the occurrence of entrapment of air bubbles into the resin material in the process of sealing the first wires <NUM> using the resin material and subsequent failures due to the sealing using the resin member <NUM>.

In addition, the thermal head 1B according to the third embodiment includes a contact portion <NUM> located between the recessed portions <NUM> adjacent to each other, and the substrate <NUM> and the wiring board <NUM> are in contact with each other at the contact portion <NUM>. Accordingly, the plurality of recessed portions <NUM> in which the resin material is accumulated are located only in areas overlapping in a plan view with the plurality of first wires <NUM> where the entrapment of air bubbles is likely to occur. Thus, according to the thermal head 1B according to the third embodiment, an increase in the usage amount of the resin member <NUM> can be suppressed.

A length L5 of the recessed portion <NUM> in a second direction intersecting a first direction may be, for example, <NUM> or more and <NUM> or less, or further <NUM> or more and <NUM> or less. In one example, the length L5 may be <NUM>. When the length L5 is less than <NUM>, it may be difficult for the resin material to enter the recessed portion <NUM>, and appropriate sealing using the resin member <NUM> may not be achieved. On the other hand, when the length L5 exceeds <NUM>, the usage amount of the resin member <NUM> may be increased.

Although the thermal printer <NUM> including the thermal head <NUM> according to the first embodiment has been described, the present invention is not limited thereto, and the thermal head 1A or 1B according to other embodiments may be included in the thermal printer <NUM>. In addition, the thermal heads <NUM> to 1B according to the plurality of embodiments may be combined.

In each of the embodiments described above, it has been described that either of the substrate <NUM> or the wiring board <NUM> includes the plurality of recessed portions and the contact portions, but the present invention is not limited thereto, and both of the substrate <NUM> and the wiring board <NUM> may include the plurality of recessed portions and the contact portions.

As described above, the thermal head <NUM> (1A, 1B) according to the embodiments includes the head base <NUM>, the wiring board <NUM>, the plurality of recessed portions <NUM> (21A, <NUM>), the contact portions <NUM>, the plurality of drive ICs <NUM>, and the plurality of wire members (first wires <NUM>), and the resin member <NUM>. The head base <NUM> includes the substrate <NUM>. The wiring board <NUM> is located adjacent to the head base <NUM>. The plurality of recessed portions <NUM> are located adjacent to the head base <NUM>. The contact portion <NUM> is located between the recessed portions <NUM> adjacent to each other, and the substrate <NUM> and the wiring board <NUM> are in contact with each other at the contact portion <NUM>. The plurality of drive ICs <NUM> are located on the first surface <NUM> of the wiring board <NUM> so as to face one by one the plurality of recessed portions <NUM>. The plurality of wire members (first wires <NUM>) are located across the recessed portions <NUM> and electrically connect the substrate <NUM> and the drive ICs <NUM>. The resin member <NUM> seals the plurality of wire members (first wires <NUM>) and the plurality of drive ICs <NUM>. Thus, the thermal head <NUM> (1A, 1B) according to the embodiments can reduce the occurrence of failures due to the sealing using the resin member <NUM> while suppressing the usage amount of the resin member <NUM>.

Claim 1:
A thermal head (<NUM>), comprising:
a head base (<NUM>) comprising
a substrate (<NUM>);
a heat storage layer (<NUM>) located on a first surface (<NUM>) of the substrate (<NUM>) along a longitudinal direction of the substrate (<NUM>);
a heat generating unit (<NUM>) located on the heat storage layer (<NUM>) being constituted by a plurality of elements arranged along the longitudinal direction of the substrate (<NUM>);
a plurality of individual electrodes (<NUM>) located side by side on one side of the heat generating unit (<NUM>) on the first surface (<NUM>) side of the substrate (<NUM>), being individually connected to the elements of the heat generating unit (<NUM>) one by one; and
a common electrode (<NUM>) located on the first surface (<NUM>) of the substrate (<NUM>) so as to surround the remaining three sides of the heat generating unit (<NUM>), being commonly connected to all of the elements of the heat generating unit (<NUM>);
a wiring board (<NUM>) located adjacent to the head base (<NUM>) ;
a heat dissipation plate (<NUM>) located on a second surface (<NUM>) side of the substrate (<NUM>), and on a second surface (<NUM>) side of the wiring board (<NUM>);
a plurality of recessed portions (<NUM>) located between the substrate (<NUM>) and the wiring board (<NUM>);
a contact portion (<NUM>) located between adjacent recessed portions (<NUM>) of the plurality of recessed portions (<NUM>), the contact portion (<NUM>) being configured to come into contact with the substrate (<NUM>) and the wiring board (<NUM>);
a plurality of drive ICs (<NUM>) located on a first surface of the wiring board (<NUM>) to face a corresponding each recessed portion (<NUM>) of the plurality of recessed portions (<NUM>);
a plurality of wire members located across the plurality of recessed portions (<NUM>), the plurality of wire members being configured to electrically connect the substrate (<NUM>) and the plurality of drive ICs (<NUM>); and
a resin member (<NUM>) configured to seal the plurality of wire members and the plurality of drive ICs (<NUM>).