JP2019064134A - Thermal head and thermal printer - Google Patents

Abstract

To provide a thermal head having a protective layer of a suitable surface shape.SOLUTION: In a thermal head, plural heating parts 23a are arranged in a D1 direction on a principal surface of a substrate. Plural lead parts 27c are connected to a +D2 side with respect to the plural heating parts 23a in a plan view. Plural connection parts 29a are connected to a -D2 side with respect to the plural heating parts 23a in the plan view. A protective layer 35 covers the plural heating parts 23a, the plural lead parts 27c and the plural connection parts 29a. In the protective layer 35, plural first recesses 53 are positioned between the plural lead parts 27c in the plan view. Plural second recesses 55 are positioned between the plural connection parts 29a in the plan view. Plural third recesses 57 are positioned between the plural heating parts 23a in the plan view, and are shallower than the plural first recesses 53 and the plural second recesses 55.SELECTED DRAWING: Figure 4

Description

  The present disclosure relates to a thermal head and a thermal printer.

  There is known a thermal head which performs printing by applying heat to thermal paper or applying heat to an ink film (ink ribbon) to perform thermal transfer (for example, Patent Document 1). Such a thermal head has, for example, a heat generating portion, an electrode for applying a voltage to the heat generating portion, and a protective layer covering them. The protective layer contributes to, for example, protecting the heat generating portion from the friction with the recording medium or the ink film. Patent Document 1 discloses a technique for forming irregularities on the upper surface of a protective layer to thereby suppress sticking. Sticking refers to a phenomenon in which a recording medium or an ink film sticks to a thermal head.

JP, 2002-370397, A

  It is desirable to provide a thermal head and thermal printer having a protective layer of a suitable surface shape.

  A thermal head according to an aspect of the present disclosure includes a plurality of heat generating portions arranged in a first direction along the predetermined surface on the predetermined surface, and the plurality of heat generating portions in plan view of the predetermined surface. And a plurality of first electrode portions connected to one side of a second direction intersecting the first direction, and the other side of the second direction with respect to the plurality of heat generating portions in a plan view of the predetermined surface A plurality of second electrode portions connected to each other, and a plurality of heat generating portions, a plurality of first electrode portions, and a protective layer covering the plurality of second electrode portions; The layer is positioned between the plurality of first recesses located between the plurality of first electrode portions in plan view of the predetermined surface and the plurality of second electrode portions in plan view of the predetermined surface. Between the plurality of second concave portions and the plurality of heat generating portions in plan view of the predetermined surface And has, it has a plurality of third recess shallower than said plurality of first recesses and the plurality of second recesses.

  In one example, the second direction is orthogonal to the first direction, and the third recess extends in a direction inclined with respect to the second direction in a plan view of the predetermined surface.

  In one example, a part of the third recess is located on an edge of the heat generating portion in the first direction.

  In one example, the third recess has a portion on the other side in the second direction connected to the second recess in the second direction.

  In one example, in the third concave portion, the one side portion in the second direction is adjacent to the first concave portion in the first direction.

  In one example, the sum of the widths in the first direction of mutually adjacent portions of the first recess and the third recess is larger than the width in the first direction of the second recess.

  In one example, the third recess includes a portion whose width in the first direction is smaller than the width in the first direction of each of the first recess and the second recess.

  A thermal head according to an aspect of the present disclosure includes a plurality of heat generating portions arranged in a first direction along the predetermined surface on the predetermined surface, and the plurality of heat generating portions in plan view of the predetermined surface. And a plurality of first electrode portions connected to one side of a second direction intersecting the first direction, and the other side of the second direction with respect to the plurality of heat generating portions in a plan view of the predetermined surface A plurality of second electrode portions connected to each other, and a plurality of heat generating portions, a plurality of first electrode portions, and a protective layer covering the plurality of second electrode portions; The layer is positioned between the plurality of first recesses located between the plurality of first electrode portions in plan view of the predetermined surface and the plurality of second electrode portions in plan view of the predetermined surface. The plurality of second recesses and the plurality of first recesses and the plurality of first recesses in plan view of the predetermined surface Includes a portion, which are adjacent to each other in one direction, this portion has a shallow third recess than the plurality of first recesses and the plurality of second recesses.

  A thermal printer according to an aspect of the present disclosure includes the above-described thermal head, a transport mechanism that transports a recording medium onto the thermal head, and a platen roller that presses the recording medium onto the thermal head. There is.

  According to the above configuration, the surface shape of the protective layer of the thermal head can be made suitable.

It is an exploded perspective view showing a schematic structure of a thermal head concerning an embodiment. It is a top view which shows the structure of the head base | substrate of the thermal head of FIG. It is sectional drawing in the III-III line of FIG. 4 (a) and 4 (b) are enlarged perspective views of a part of the head base of FIG. It is a top view which expands and shows the protective layer of a head base | substrate. 6 (a), 6 (b) and 6 (c) are cross-sectional views taken along the lines VIa-VIa, VIb-VIb and VIc-VIc of FIG. It is a schematic diagram which shows the structure of a thermal printer which has a thermal head of FIG. It is a perspective view which expands and shows a part of thermal head concerning a modification.

  Hereinafter, the thermal head 1 according to the embodiment will be described with reference to the drawings. In the drawing, for convenience, an orthogonal coordinate system including D1 axis, D2 axis and D3 axis is added. The thermal head 1 may have any direction upward or downward, but for convenience, the term such as the upper surface may be used with the positive side of the D3 axis upward.

(Whole structure of the thermal head)
FIG. 1 is an exploded perspective view showing a schematic configuration of the thermal head 1.

  The thermal head 1 is configured to print on a recording medium conveyed in the D2 direction (for example, the + D2 side) on the positive side of the D3 axis. The recording medium is, for example, a thermal paper, and printing is performed by applying heat from the main surface 1 a facing the D3 axis positive side of the thermal head 1. Alternatively, for example, the recording medium is a paper other than the thermal paper, and printing is performed by performing heat transfer by applying heat from the main surface 1 a of the thermal head 1 to the ink film stacked on the paper. In the following, thermal paper may be taken as an example of the recording medium. Moreover, a main surface points out the largest surface (front or back) of a plate-shaped member.

  The thermal head 1 includes, for example, a head substrate 3 constituting the main surface 1 a, a heat dissipation plate 5 positioned on the back surface of the head substrate 3, and an adhesive member 7 interposed between the head substrate 3 and the heat dissipation plate 5. And a connector 9 connected to the head base 3.

  The head substrate 3 has a heating line 3 b for applying heat to the thermal paper (or ink film) on the main surface 1 a side. The heating line 3b is comprised by the several heating part 3c arranged in D1 direction. Although FIG. 1 illustrates the boundaries of the plurality of heating units 3 c, the boundaries do not necessarily appear in the appearance of the head substrate 3. When the thermal paper slides on the heating line 3b in the D2 direction (strictly, it may include the component in the D3 direction), the temperatures of the plurality of heating units 3c are individually controlled to make the thermal paper An arbitrary two-dimensional image is formed.

  The head substrate 3 is formed in, for example, a rectangular shape having a long side extending in the D1 direction and a short side extending in the D2 direction in plan view. The heating line 3b is located, for example, on one side (one long side in the illustrated example) side of the center of the head base 3 and extends along (for example, in parallel with) the one side. The side (the other long side in the illustrated example) opposite to one side along the heating line 3b of the head base 3 is the terminal side to which the connector 9 is connected.

  The heat sink 5 has a rectangular parallelepiped shape. The heat sink 5 is formed of, for example, a metal material such as copper, iron or aluminum, and has a function of radiating the heat which does not contribute to the printing among the heat generated in the heating line 3b of the head substrate 3 . The bonding member 7 bonds the head base 3 and the heat sink 5 to each other.

  The connector 9 electrically connects the head base 3 and an electronic circuit outside the thermal head 1. By inputting an electrical signal (voltage) from the external electronic circuit to the head substrate 3 via the connector 9, the temperatures of the plurality of heating units 3c are individually controlled. The connector 9 has, for example, a plurality of pins 9 a that abut on a plurality of terminals 3 d (see FIG. 2) of the head base 3. The plurality of pins 9a are, for example, resin-sealed. In addition, it may replace with the connector 9 of such a structure, and a flexible printed wiring board (FPC) may be used.

(Structure of head substrate)
FIG. 2 is a plan view showing the main configuration of the head base 3. FIG. 3 is a cross-sectional view taken along line III-III of FIG. In FIG. 2 and FIG. 3, some members (described later) are not shown or shown by lines other than solid lines. Further, in FIG. 2, the surface (surface which is not a cross section) is hatched in order to facilitate the illustration of some members (described later). Further, in FIG. 3, the part on the negative side of the D2 axis is omitted or schematically illustrated because it becomes difficult to illustrate if its details are accurately reflected.

  The head substrate 3 has a substrate 11 and various layers stacked on the surface thereof. Hereinafter, each member which comprises the head base 3 is demonstrated.

(substrate)
The substrate 11 is formed of an electrically insulating material such as alumina ceramics or a semiconductor material such as single crystal silicon. The shape of the substrate 11 is generally the same as the shape of the head base 3. That is, in the present embodiment, the shape of the substrate 11 is generally a plate shape having the thickness direction in the D3 direction, and the shape in plan view has a long side extending in the D1 direction and a short side extending in the D2 direction. It is rectangular.

(Reinforcing conductor layer)
The reinforcing conductor layer 13 (FIG. 3) is provided on the substrate 11. The reinforcing conductor layer 13 has, for example, an effect similar to that of thickening the common electrode 27 and the like, which will be described later, and contributes to reducing the wiring resistance. The position in the plan view may be set appropriately. The material of the reinforcing conductor layer 13 may be an appropriate metal, such as silver (Ag) or copper (Cu) or an alloy thereof. The reinforcing conductor layer 13 is formed, for example, by applying a predetermined conductive paste obtained by adding and mixing an organic solvent or the like to a metal powder such as Ag or Cu on the upper surface of the substrate 11 by screen printing or the like and baking it. It is formed.

(Glazed layer)
The glaze layer 15 (FIG. 3) is provided on the substrate 11 (from the top when the reinforcing conductor layer 13 is disposed). The glaze layer 15 has a first glaze 17 constituting an inner side of the heating line 3 b and a second glaze 19 which is separated from the first glaze 17 and extends in a relatively wide range. For example, the first glaze 17 contributes to heat storage and / or contributes to appropriately shaping the surface of the heating line 3b. The second glaze 19 is formed to be flatter than the surface of the substrate 11, for example, to reduce the risk of disconnection and / or short circuit of the conductive layer formed thereon.

  The first glaze 17 extends linearly (for example, in parallel) along the direction D1 with a constant width, for example. The shape of the cross section orthogonal to the D1 axis of the first glaze 17 is, for example, a dome shape (curved shape protruding outward). The height, width and curvature may be set as appropriate. Also, the curve may be a circular arc or may have a curvature that changes like an arc of an ellipse.

  The cross-sectional shape of the first glaze 17 may be, for example, a flat upper surface (for example, a rectangular or trapezoidal shape) other than a dome shape, or a shape (for example, an upper surface) The bottom may be a flat surface or a frustum shape having a curved surface, or it may be a shape (two-step shape) in which a protrusion protrudes from a dome-shaped upper surface.

  Since the surface of the first glaze 17 is a curved surface, the layer on the first glaze 17 also has a curved surface. In the following, when the layer on the first glaze 17 is referred to as a planar shape (also referred to simply as a shape), it refers to, for example, a shape viewed in the D3 direction (a shape projected onto the main surface of the substrate 11). . However, the planar shape may be regarded as a shape in which a curved surface is developed into a planar shape.

  The second glaze 19 is provided, for example, over substantially the entire main surface of the substrate 11 and is separated from the first glaze 17.

  The thickness of the first glaze 17 and the second glaze 19 may be set appropriately. For example, the thickness of the first glaze 17 and the second glaze 19 is 30 μm or more and 80 μm or less.

  The first glaze 17 and the second glaze 19 can be produced, for example, by respectively printing a predetermined glass paste obtained by mixing a glass powder with a suitable organic solvent, and then firing the glass paste.

(Underlayer)
An underlayer 21 (FIG. 3) is provided on the glaze layer 15. The underlayer 21 contributes to, for example, reducing the risk of etching the layer below the underlayer 21 when the layer above the underlayer 21 is etched in the process of manufacturing the head substrate 3. The foundation layer 21 is provided, for example, over substantially the entire surface of the main surface of the substrate 11, and directly overlaps the main surface of the substrate 11 in the non-arrangement region of the glaze layer 15.

  The underlayer 21 can be formed, for example, using a material such as SiC, SiN, or SiALON by a thin film forming technique such as sputtering. The thickness of the base layer 21 may be appropriately set, and is, for example, 0.01 μm or more and 1 μm or less. The underlayer 21 does not have to be necessarily provided.

(Heating body layer)
A heat generating layer 23 is provided on the underlayer 21. In FIG. 2, the surface of the heating element layer 23 is hatched. The heat generating body layer 23 includes a plurality of heat generating portions 23 a (in the heat generating body layer 23 exposed from a conductive layer 25 described later) in the heating line 3 b (on the first glaze 17). The heat generated in the heat generating portion 23a is applied to the recording medium or the ink film.

  The entire planar shape (pattern) of the heating element layer 23 is, for example, the same as the planar shape of the conductive layer 25 to be described later, except for the plurality of heat generating portions 23 a. The heating element layer 23 may be configured of only the plurality of heating portions 23a, or only the heating portion 23a and the surrounding portion. Although the thickness of the heat generating body layer 23 may be set suitably, it is 0.01 micrometer or more and 0.5 micrometer or less, for example.

  The plurality of heat generating portions 23a are, for example, arranged in a line in a straight line (for example, in parallel) along the direction D1. The pitch of the plurality of heat generating parts 23a (the pitch of the plurality of heating parts 3c) is, for example, constant. The number and density of the plurality of heat generating parts 23a may be set appropriately. For example, the density is 100 dpi (dot per inch) or more and 2400 dpi or less. In the drawings of this embodiment, the heat generating portion 23a is shown at the top of the first glaze 17. However, even if the heat generating portion 23a is deviated to the -D2 side or + D2 side with respect to the top of the first glaze 17. Good.

  The heat generating layer 23 is formed of, for example, a material having a relatively high electric resistance, such as a TaN system, a TaSiO system, a TaSiNO system, a TiSiO system, a TiSiO system, a TiSiCO system or an NbSiO system. Therefore, when a voltage is applied to the heat generating portion 23a, the heat generating portion 23a generates heat by Joule heat generation.

  The heating element layer 23 is formed, for example, by forming a thin film by a thin film forming technique such as a sputtering method and then processing the thin film into a predetermined pattern using photo etching or the like. The etching of the heating element layer 23 may be performed together with the etching of the conductive layer 25 (except for the etching on the heating portion 23a).

(Conductive layer)
A conductive layer 25 is provided on the heating element layer 23. The conductive layer 25 has, for example, a common electrode 27 and a plurality of individual electrodes 29 for applying a voltage to the plurality of heat generating portions 23a, a plurality of wirings 31 (FIG. 2) for performing various electrical connections, and a ground potential (reference potential) And the ground electrode 33 (FIG. 2) to be applied.

  The common electrode 27 is commonly connected to the plurality of heat generating portions 23a, and applies the same potential to the plurality of heat generating portions 23a. The plurality of individual electrodes 29 are separately (for example, one by one) separately connected to the plurality of heat generating portions 23a, and apply a potential to the plurality of heat generating portions 23a independently of each other. Thereby, voltages are applied to the plurality of heat generating portions 23a sandwiched between the plurality of common electrodes 27 and the plurality of individual electrodes 29 in plan view independently of each other, and printing of an arbitrary image becomes possible.

  For example, a predetermined potential is applied to the common electrode 27 from the connector 9. Drive signals (potentials) are applied to the plurality of individual electrodes 29 from a drive IC 45 (FIG. 2) described later. More specifically, for example, the plurality of individual electrodes 29 (the plurality of heat generating portions 23a) are divided into a plurality of groups, and the individual electrodes 29 of each group are provided in correspondence with the respective groups. The drive signal is input from

  The plurality of wirings 31 are responsible for connection between the drive IC 45 and the connector 9 or connection between the plurality of drive ICs 45, and contributes to inputting a signal according to the content of an image to the drive IC 45. The ground electrode 33 connects, for example, the drive IC 45 and the connector 9 and contributes to applying a reference potential to the drive IC 45.

  The conductive layer 25 is made of, for example, an appropriate metal such as aluminum (Al) or an aluminum alloy. Although the thickness may be set suitably, it is 0.5 micrometer or more and 2.0 micrometers or less, for example. The conductive layer 25 is formed, for example, by forming a thin film by a thin film forming technique such as a sputtering method and processing the thin film into a predetermined pattern using photo etching or the like. The etching may be performed in two steps: a process of etching the heating element layer 23 and the conductive layer 25 together and a process of etching the conductive layer 25 directly on the heating portion 23a.

(Common electrode)
The common electrode 27 is a main wiring portion located on the side (+ D2) opposite to the terminal side of the head base 3 with respect to the plurality of heat generating portions 23a (the first glaze 17), as shown in FIG. 27a, a sub wiring portion 27b extending from the main wiring portion 27a to the terminal side of the head substrate 3, and a plurality of lead portions 27c extending from the main wiring portion 27a and individually connected to the plurality of heat generating portions 23a ing.

  The main wiring portion 27a linearly extends along the first glaze 17 (for example, in parallel) with a constant width at a position not overlapping the first glaze 17, for example.

  The sub-wiring portion 27b extends from the end of the main wiring portion 27a, for example, and is adjacent to the edge on the -D2 side of the substrate 11 via the end outside (the outside in the D1 direction) of the first glaze 17 It extends to the position. A part of the end portion on the −D 2 side of the sub wiring portion 27 b constitutes a terminal 3 d to which the pin 9 a of the connector 9 is connected. The common electrode 27 may be configured such that a potential is applied from the drive IC 45 instead of the connector 9.

  For example, the plurality of lead portions 27c are provided in one-to-one correspondence with the plurality of heat generating portions 23a, and extend linearly from the main wiring portion 27a along the direction D2 (for example, parallel) with a constant width It is connected to the + D2 side of the heat generating portion 23a. The whole of the lead portion 27 c may be located on the first glaze 17 or a part on the tip end side may be located on the first glaze 17.

(Individual electrode)
The plurality of individual electrodes 29 are provided, for example, in one-to-one correspondence with the plurality of heat generating portions 23a. Also, the plurality of individual electrodes 29 extend, for example, gradually from the center side of the substrate 11 toward the first glaze 17 while gradually increasing the width and the pitch. After that, the plurality of individual electrodes 29 (connections 29a among them) linearly extend along the D2 direction (for example, in parallel) with a constant width and are connected to the -D2 side of the plurality of heating portions 23a There is. The whole of the connection portion 29 a may be located on the first glaze 17, or a part on the tip end side may be located on the first glaze 17. Note that, unlike the illustrated example, two or more heat generating portions 23 a adjacent to each other may be connected to one individual electrode 29. An end of the plurality of individual electrodes 29 opposite to the plurality of heat generating portions 23 a constitutes a pad 3 e (FIG. 2) for mounting the drive IC 45 on the surface.

(Wiring and ground electrode)
The plurality of wires 31 connecting the drive IC 45 and the connector 9 constitute a pad 3e on one surface of which the surface is mounted on the drive IC 45, and the other end constitutes a terminal 3d to which the connector 9 is connected. The plurality of wirings 31 connecting the drive ICs 45 form a pad 3e on one end of which the drive IC 45 is mounted on the surface, and the other end forms a pad 3e on which the other drive ICs 45 are mounted on the surface. The head base 3 may have a circuit configuration in which the wiring 31 connecting the drive ICs 45 is not provided.

  The ground electrode 33 is, for example, formed in a solid shape in a region surrounded by the individual electrode 29, the common electrode 27, and the plurality of wirings 31. A part of the ground electrode 33 constitutes a pad 3e on which the drive IC 45 is mounted on the surface, and another part constitutes a terminal 3d to which the connector 9 is connected.

(Protective layer)
A protective layer 35 (FIG. 3) is provided on the conductive layer 25. In FIG. 2, the protective layer 35 is omitted. The protective layer 35 contributes to, for example, suppressing the wear of the heating element layer 23 and the conductive layer 25 due to the contact with the recording medium, and suppressing the oxidation and corrosion of these layers.

  The protective layer 35 is formed to cover at least a plurality of heat generating portions 23 a. Specifically, for example, the protective layer 35 has a width covering the entire first glaze 17. Further, in the illustrated example, the protective layer 35 extends to the outside of the first glaze 17. The protective layer 35 extends, for example, linearly along the first glaze 17 (for example, in parallel) with a constant width.

  The protective layer 35 can be formed using SiN, SiO, SiON, SiC, SiCN, or diamond like carbon. The protective layer 35 may be configured as a single layer as in this embodiment, or may be configured by stacking a plurality of layers. The protective layer 35 can be manufactured using a thin film forming technique such as a sputtering method or a thick film forming technique such as screen printing. The thickness of the protective layer 35 may be set as appropriate, but, for example, is thicker than the total of the thicknesses of the heat generating layer 23 and the conductive layer 25 and is 3 μm or more and 20 μm or less.

(Cover layer)
A covering layer 37 (FIG. 3) is provided in the non-arrangement area of the protective layer 35. In FIG. 2, the covering layer 37 is not shown. Also, the covering layer 37 may overlap a part of the protective layer 35. The covering layer 37 contributes, for example, to the insulation between the conductive layer 25 and the outside of the head base 3 and to the suppression of oxidation and corrosion of the conductive layer 25.

  The covering layer 37 is provided on substantially the entire surface of the substrate 11 while exposing the heating line 3 b, the plurality of pads 3 e, and the plurality of terminals 3 d, for example. The thickness of the covering layer is 5 μm or more and 30 μm or less. The material of the covering layer 37 is a resin material such as an epoxy resin, a polyimide resin, or a silicone resin. The covering layer 37 is formed by, for example, screen printing or photolithography.

(Drive IC)
The drive IC 45 has a function of controlling the energization state of each heat generating portion 23a. As the drive IC 45, for example, a switching member having a plurality of switching elements inside may be used. The drive IC 45 is surface-mounted on the plurality of pads 3 e via bumps (not shown) and sealed by the hard coat 47 (see FIG. 7). The hard coat 47 is made of, for example, a resin such as an epoxy resin or a silicone resin.

(Surface shape of protective layer)
FIGS. 4A and 4B are perspective views showing a part of the head base 3 in an enlarged manner. In FIG. 4A, the protective layer 35 is omitted from FIG. 4B.

  As described above, the plurality of heat generating portions 23a are arranged in the D1 direction. A plurality of lead portions 27c of the common electrode 27 are connected to the + D2 side of each heat generating portion 23a. The connection part 29a of the individual electrode 29 is connected to the -D2 side of each heat generating part 23a.

  For example, the lead portion 27c, the heat generating portion 23a, and the connection portion 29a, as a whole, generally constitute a ridge (reference numeral omitted) linearly extending with a constant width (for example, in parallel) along the D2 direction. doing. In another viewpoint, a plurality of lower grooves 51 (FIG. 4A) extending in the D2 direction are formed.

  As described above, the planar shape (pattern) of the heat generating layer 23 is the same as the pattern of the conductive layer 25 (the common electrode 27 and the individual electrode 29) except for the heat generating portion 23a. Therefore, the lower groove 51 has a depth corresponding to the total of the thickness of the heat generating layer 23 and the thickness of the conductive layer 25 at positions between the plurality of lead portions 27c and between the plurality of connection portions 29a. ing.

  In the protective layer 35 overlapping the first concave portion 53, the second concave portion 55, and the third concave portion 57 are formed at positions generally overlapping the lower groove 51. The first concave portion 53 is a concave portion in which at least a part is positioned between the lead portions 27c adjacent to each other in a plan view. The second concave portion 55 is a concave portion in which at least a portion is located between the connection portions 29a adjacent to each other in a plan view. The third concave portion 57 is a concave portion at least a part of which is located between the heat generating portions 23a adjacent to each other in a plan view.

  Although not shown in particular, the protective layer 35 may have a recess that substantially overlaps the heating portion 23a. The recess may or may not be connected to the third recess 57 in the D1 direction. Further, the depth of the recess may be shallow, approximately the same as, or deep with respect to the depth of the third recess 57.

  FIG. 5 is a plan view showing the upper surface of the protective layer 35 in an enlarged manner. In this figure, the lead portion 27c, the heat generating portion 23a and the connecting portion 29a are also shown by dotted lines. In addition, the heating portion 23a is hatched. 6 (a) to 6 (c) are schematic cross-sectional views of the upper surface portion of the protective layer 35, and FIG. 6 (a) corresponds to the line VIa-VIa of FIG. b) corresponds to the VIb-VIb line of FIG. 5, and FIG. 6 (c) corresponds to the VIc-VIc line of FIG.

(First recess and second recess)
Each of the first recess 53 and the second recess 55 is, for example, a recess extending substantially in a straight line with a constant width in parallel to the D2 direction in plan view. In the concave groove, the end opposite to the heat generating portion 23a may be located on the first glaze 17 or may be located on the long side (edge) of the first glaze 17 And may be located outside the first glaze 17 (example shown). Further, the end on the heat generating portion 23a side may be located on the first glaze 17 on the premise that the heat generating portion 23a is located further to the heat generating portion 23a than the end on the opposite side to the heat generating portion 23a. (The illustrated example) may be located at the edge (long side) of the first glaze 17 in the D2 direction, or may be located outside the first glaze 17. The end on the heat generating portion 23a side may reach the position of the heat generating portion 23a in the direction D2, or may be located outside the heat generating portion 23a (example in the drawing).

  The cross-sectional shapes of the first recess 53 and the second recess 55 (the shape of the cross section orthogonal to the D2 axis; the same applies hereinafter) may be an appropriate shape, for example, a substantially rectangular shape. Alternatively, for example, the cross-sectional shape is a shape in which the width becomes narrower toward the bottom side in the entire depth direction or from an appropriate depth to the bottom side. Either of the width and the depth of the first recess 53 and the second recess 55 may be larger than the other.

  When the first recess 53 or the second recess 55 has a portion located outside the first glaze 17, the cross-sectional shape of the portion is constant, for example, regardless of the position in the D2 direction. When the first concave portion 53 or the second concave portion 55 has a portion located on the first glaze 17, the cross-sectional shape of the portion is, for example, shallower as if the upper portion of the groove is shaved closer to the heat generating portion 23a side. (For example, the protective layer 35 may be thin). In FIG. 4B and FIG. 5, although the edges on the vertex side of the first glaze 17 of the first recess 53 and the second recess 55 are clearly shown, these recesses are the vertices of the first glaze 17. As it approaches, it may become shallow gradually and the edge by the side of the top may become unclear.

  Although the width w1 (FIG. 6A) of the first concave portion 53 depends on the film formation state of the protective layer 35, for example, it is approximately equal to the distance between the lead portions 27c. Similarly, although the width w2 (FIG. 6C) of the second recess 55 depends on the film formation state of the protective layer 35, for example, it is approximately equal to the distance between the connection portions 29a. The widths w1 and w2 are, for example, equal in size to each other. The width of the recess (53, 55 or 57) may be specified, for example, at an intermediate position between the upper opening of the recess (upper surface of the protective layer 35) and the deepest position of the recess. The widths w1 and w2 are, for example, 1 μm or more and 150 μm or less.

  Although the depth d1 of the first concave portion 53 (FIG. 6A) and the depth d2 of the second concave portion 55 depend on the film formation state of the protective layer 35, for example, the total of the heating element layer 23 and the conductive layer 25. It is less than the thickness. The depths d1 and d2 are, for example, equal in size to each other. The depth of the recess (53, 55 or 57) may be specified, for example, at the deepest position of the recess or at the center of the width of the upper opening of the recess. Further, in the case where the protective layer 35 has a curved surface shape as in the present embodiment, the depth may be specified in the normal direction, or in the D3 direction when the curvature is relatively small, etc. It is also good. The depths d1 and d2 are, for example, 0.5 μm or more and 2 μm or less.

(Third recess)
The third concave portion 57 is, for example, a concave groove extending in a straight line with a constant width in a direction inclined in the direction D2 in a plan view. In the concave groove, the end on the second concave 55 side is connected to the end of the second concave 55 in the D2 direction, for example. Further, an end on the first concave 53 side is adjacent to, for example, the first concave 53 in the D1 direction.

  When the second concave portion 55 and the third concave portion 57 are connected in the D2 direction, for example, the overlapping amount of the two in the D1 direction at the connected position corresponds to the third concave portion 57 of the second concave portion 55 A state in which 70% or more of the length in the D1 direction in the portion immediately before connecting and / or 70% or more of the length in the D1 direction immediately before connecting to the second recess 55 of the third recess 57 may be included.

  When the first recess 53 and the third recess 57 are adjacent to each other in the D1 direction, for example, they are separated on the premise that a part of the arrangement range in the D2 direction of the two overlaps with each other. If the two are connected (in the example shown), the overlapping amount in the D1 direction at the connected position is immediately before the overlapping of the first recess 53 with the third recess 57. It may include less than 30% of the length in the D1 direction in the portion and less than 30% of the length in the D1 direction of the third recess 57 immediately before overlapping with the second recess 55.

  The end of the third recess 57 on the second recess 55 side (−D2 side) is connected to the end of the second recess 55 on the third recess 57 side. The description of the end position of the third concave portion 57 may be taken as the description of the end position of the third concave portion 57 on the second concave portion 55 side. That is, the end on the second recess 55 side of the third recess 57 may be located on the first glaze 17 (the example shown), or the edge on the -D2 side of the first glaze 17 (long side ), Or may be located outside the first glaze 17 (−D2 side). The end of the third recess 57 on the second recess 55 side may fall within the range of the heat generating portion 23a in the D2 direction, and is located outside (−D2 side) of the heat generating portion 23a. It may be (example shown).

  The end of the third recess 57 on the first recess 53 side (+ D2 side) may be located on the first glaze 17 (example shown), or the edge (length) of the first glaze 17 on the + D 2 side It may be located on the side), and may be located outside the first glaze 17 (on the + D 2 side). The end of the third recess 57 on the first recess 53 side may be within the range of the heat generating portion 23a in the D2 direction, and is located outside (+ D2 side) of the heat generating portion 23a. It is also good (example shown).

  For example, while the third concave portion 57 is partially located between the heat generating portions 23 a by being inclined in a plan view, the other portion overlaps the heat generating portions 23 a. More specifically, the third recess 57 is located on the edge (at least a part of) the heat generating portion 23a on the -D2 side. The ratio of the area ratio of the portion of the third concave portion 57 located between the heat generating portion 23a and the portion positioned on the heat generating portion 23a, or the ratio of the area where the third concave portion 57 overlaps the heat generating portion 23a to the area of the heat generating portion 23a is It may be set appropriately. For example, the ratio of the area in which the third recess 57 overlaps the heat generating portion 23a to the area of the heat generating portion 23a is 10% or less or 5% or less. Although not particularly illustrated, the third concave portion 57 may not overlap the heating portion 23a.

  The cross-sectional shape (the shape of the cross section orthogonal to the D2 axis; the same applies hereinafter) of the third concave portion 57 may be an appropriate shape, and is, for example, a substantially rectangular shape. Alternatively, for example, the cross-sectional shape is a shape in which the width becomes narrower toward the bottom side in the entire depth direction or from an appropriate depth to the bottom side. The third concave portion 57 may have either the width or the depth larger than the other, and in the example shown in FIG. 6B, the depth d3 is smaller than the width w3. At least a portion (all in the illustrated example) of the third recess 57 is located on the first glaze 17. The cross-sectional shape of the portion on the first glaze 17 may be, for example, shallower as if the upper portion of the groove is scraped as it approaches the heat generating portion 23a side (for example, the protective layer 35 may be thinner) ).

  The width w3 of the third recess 57 (FIG. 6B, here, the length in the D1 direction) is, for example, approximately equal to the width w1 of the first recess 53 and / or the width w2 of the second recess 55. is there. For example, the difference between the width w3 and the width w1 or w2 is less than 20% of the latter.

  The depth d3 (FIG. 6B) of the third recess 57 is, for example, smaller than the depth d1 of the first recess 53 and the depth d2 of the second recess 55, respectively. For example, the depth d3 is 1/5 or less, 1/10 or less, or 1/20 or less of the depth d1 and the depth d2, respectively. In the above, when the value changes depending on the position in the D2 direction with respect to each depth d1, d2 or d3, for example, comparison may be performed using the largest value, or positions where they are connected to or adjacent to each other The comparison may be made using the values in.

  In a region where the range in the direction D2 overlaps with each other in the first recess 53 and the third recess 57, a relatively deep portion (a portion with a depth d1) is a part of the first recess 53, and the relative The shallow portion (portion of depth d3) is a part of the third recess 57. Therefore, as shown to Fig.6 (a), when the part adjacent to the 1st recessed part 53 among the 3rd recessed parts 57 is connected with the 1st recessed part 53 and D1 direction, width w4 of the said part ( Here, the length in the direction D1) is narrower than the width w3 of the other portion of the third recess 57. Thus, for example, the width w4 is narrower than the width w1 and / or the width w2.

  The head substrate 3 may be manufactured by the same method as various known methods except for the formation of the third recess 57. Also, the method of forming the various layers on the substrate 11 is as already mentioned. For example, when the protective layer 35 is formed, the first concave portion 53 and the second concave portion 55 are partially formed in the lower groove 51 as if the protective groove 35 is partially sunk by the lower groove 51. It is formed by

  The third recess 57 may be formed by an appropriate method. For example, although not shown in the drawings, after the head substrate 3 is manufactured by the known method as described above, the second substrate 55 is moved from the second recess 55 to the + D2 side by the fixed abrasive while transporting the head substrate 3 to the -D1 side. Polish with a width of 55. As a result, a third recess 57 which is relatively shallow and has a width equal to that of the second recess 55 and which extends to the + D2 side while being inclined to the + D1 side is formed.

(Thermal printer)
FIG. 7 is a schematic view showing the configuration of a thermal printer 101 having the thermal head 1.

  The thermal printer 101 includes a thermal head 1, a conveyance mechanism 103 for conveying a recording medium P (for example, thermal paper), a platen roller 105 for pressing the recording medium P against the heating line 3b, and a power supply for supplying power thereto. A device 107 and a control device 109 for controlling these operations are provided.

  The thermal head 1 is mounted on a mounting surface 111 a of a mounting member 111 provided on a housing (not shown) of the thermal printer 101. The thermal head 1 is attached to the attachment member 111 along the main scanning direction (D1 axis direction) which is a direction orthogonal to the conveyance direction S of the recording medium P.

  The conveyance mechanism 103 includes a drive unit (not shown) and conveyance rollers 113, 115, 117, and 119. The transport mechanism 103 transports the recording medium P in the direction of the arrow S, and transports the recording medium P onto the protective layer 35 positioned on the plurality of heat generating portions 23 a of the thermal head 1. The drive unit has a function of driving the conveyance rollers 113, 115, 117, 119, and for example, a motor can be used. The conveying rollers 113, 115, 117, 119 cover cylindrical shaft bodies 113a, 115a, 117a, 119a made of metal such as stainless steel with elastic members 113b, 115b, 117b, 119b made of butadiene rubber etc. Can be configured.

  Although not shown, when the recording medium P is an image receiving paper or the like to which ink is transferred, the ink film is transported together with the recording medium P between the recording medium P and the heat generating portion 23 a of the thermal head 1.

  The platen roller 105 is disposed to extend along a direction orthogonal to the conveyance direction S of the recording medium P, and both ends are supported and fixed so that the recording medium P can be rotated in a state of pressing the heat generating portion 23a. ing. The platen roller 105 can be configured, for example, by covering a cylindrical shaft 105a made of metal such as stainless steel with an elastic member 105b made of butadiene rubber or the like.

  As described above, the power supply device 107 has a function of supplying a current for heating the heating portion 23 a of the thermal head 1 and a current for operating the drive IC 45. The control device 109 supplies a control signal for controlling the operation of the drive IC 45 to the drive IC 45 in order to cause the heat generating portion 23 a of the thermal head 1 to selectively generate heat.

  The thermal printer 101 causes the platen roller 105 to press the recording medium P onto the heat generating portion 23 a of the thermal head 1, and the conveyance mechanism 103 to convey the recording medium P onto the heat generating portion 23 a. Thus, predetermined heating is performed on the recording medium P by selectively heating the heat generating portion 23a. When the recording medium P is an image receiving paper or the like, printing on the recording medium P is performed by thermally transferring the ink of an ink film (not shown) conveyed together with the recording medium P onto the recording medium P.

  As described above, in the present embodiment, the thermal head 1 includes the plurality of heat generating portions 23a, the plurality of first electrode portions (lead portions 27c), the plurality of second electrode portions (connection portions 29a), and the protective layer 35. And. The plurality of heat generating portions 23a are arranged in a first direction (D1 direction) along the main surface of the substrate 11 on a predetermined surface (for example, the main surface of the substrate 11 or the base layer 21). The plurality of lead portions 27c are connected to one side (+ D2 side) in a second direction (direction D2) intersecting the direction D1 with the plurality of heat generating portions 23a in plan view. The plurality of connection portions 29a are connected to the other side (−D2 side) in the D2 direction with respect to the plurality of heat generating portions 23a in plan view. The protective layer 35 covers the plurality of heat generating portions 23 a, the plurality of lead portions 27 c, and the plurality of connection portions 29 a. The protective layer 35 also has a plurality of first recesses 53, a plurality of second recesses 55, and a plurality of third recesses 57. The plurality of first recesses 53 are located between the plurality of lead portions 27 c in plan view. The plurality of second recesses 55 are located between the plurality of connection portions 29 a in plan view. The plurality of third recesses 57 are located between the plurality of heat generating portions 23 a in plan view, and are shallower than the plurality of first recesses 53 and the plurality of second recesses 55.

  Therefore, for example, since the third concave portion 57 is located between the heat generating portions 23a, the possibility that the recording medium or the ink film will stick to the area on the heat generating portions 23a of the protective layer 35 (sticking occurs) is reduced. Ru. On the other hand, since the third recess 57 is relatively shallow, for example, dust such as paper waste (paper dust) generated by sliding is easily discharged from the third recess 57. As a result, for example, the possibility of the characteristics related to heating being changed by the dust deposited in the third concave portion 57 is reduced, and the image quality is maintained.

  Further, in the present embodiment, the third recess 57 extends in a direction inclined with respect to the D2 direction in plan view.

  Therefore, for example, when focusing on a linear region parallel to the D1 direction in the recording medium, when the region slides in the D2 direction with respect to the head substrate 3, the contact position with the protective layer 35 (reversely In other words, the position immediately above the third recess 57 changes in the D1 direction with the sliding. That is, the contact state changes. As a result, for example, the recording medium is easily peeled off from the protective layer 35. That is, the risk of sticking is reduced.

  Further, in the present embodiment, a part of the third concave portion 57 is located on the edge of the heat generating portion 23 a in the D1 direction (−D1 side).

  Therefore, for example, the effect of suppressing the sticking can be obtained at the edge of the heat generating portion 23a. As a result, for example, the sliding of the recording medium with respect to the heating line 3b is made particularly smooth on the heat generating portion 23a, and consequently, the spacing of dots in the direction D1 on the recording medium is stabilized. That is, the image quality is improved.

  Further, in the present embodiment, in the third concave portion 57, a portion on the −D2 side is connected to the second concave portion 55 in the D2 direction.

  Therefore, for example, dust such as paper waste that has entered the second recess 55 can be discharged to the third recess 57. As described above, since the third recess 57 is relatively shallow, it is easy to discharge dust. As a result, the discharge of dust is facilitated as compared to the case where the dust is discharged from the second recess 55 directly to the outside. The effect is further enhanced when the second recess 55 is located upstream of the third recess 57 relative to the head base 3 of the recording medium.

  Further, in the present embodiment, in the third recess 57, the portion on the + D2 side is adjacent to the first recess 53 in the D1 direction.

  Therefore, for example, the contact area between the recording medium and the protective layer 35 can be further reduced. As a result, for example, the effect of suppressing sticking is improved.

  Further, in the present embodiment, the sum (w1 + w4) of the widths of the first recess 53 and the third recess 57 adjacent to each other in the D1 direction is larger than the width w2 of the second recess 55 in the D1 direction.

  Therefore, both the action of reducing the contact area between the recording medium and the protective layer 35 and the action of changing the contact state along with the sliding of the recording medium are exhibited, and the effect of suppressing the sticking becomes higher.

  In the present embodiment, the width of the third recess 57 in the D1 direction includes a portion (for example, a portion with a width w4) smaller than the width w1 or w2 in the D1 direction of each of the first recess 53 and the second recess 55. There is.

  Therefore, while the contact area between the recording medium and the protective layer 35 is reduced by the third concave portion 57, the third concave portion 57 itself is made thinner. Thereby, for example, it is facilitated to arrange the third recess 57 in a proper position with a necessary and sufficient area.

  The present embodiment can be grasped from a viewpoint different from the viewpoint that the third concave portion 57 is located between the heating portion 23a in plan view and is shallower than the first concave portion 53 and the second concave portion 55. For example, the third recess 57 is adjacent to the first recess 53 in the direction D1 in plan view, and is shallower than the first recess 53 and the second recess 55.

  In this aspect, for example, the third recess 57 substantially expands the first recess 53 in the D1 direction to reduce the possibility of sticking. On the other hand, since the third concave portion 57 is relatively shallow, for example, dust such as paper waste is easily discharged.

(Modification)
FIG. 8 is an enlarged perspective view showing a part of a thermal head according to a modification, and corresponds to FIG. 4 (b).

  In this modification, the third recess 57 of the embodiment is divided into a first divided recess 57 a and a second divided recess 57 b. For example, the first divisional recess 57a and the second divisional recess 57b are shallower toward the heat generating portion 23a (for example, the protective layer 35 is thinner), and as a result, are disconnected at the heat generating portion 23a. The first divisional recess 57a and the second divisional recess 57b may or may not have a portion located between the adjacent heat generating portions 23a in a plan view.

  Also in this modification, for example, the first divisional recess 57a is adjacent to the first recess 53 in the direction D1 in plan view, similarly to the third recess 57 of the embodiment, and the first recess 53 and the second recess 55a. Since it is shallower, the same effect as that of the embodiment can be obtained. For example, the first recess 53 can be substantially expanded in the direction D1 by the third recess 57 to reduce the possibility of sticking. On the other hand, since the third concave portion 57 is relatively shallow, for example, dust such as paper waste is easily discharged.

  In the above embodiment and modification, the main surface or the base layer 21 of the substrate 11 is an example of the predetermined surface. The D1 direction is an example of a first direction. The D2 direction is an example of a second direction. The lead portion 27c is an example of a first electrode portion. The connection portion 29a is an example of a second electrode portion. The third recess 57 and the first divided recess 57a are examples of a third recess.

  The technology according to the present disclosure is not limited to the above-described embodiments and modifications, and may be implemented in various aspects.

  For example, although the heating line 3b is provided on the main surface of the substrate 11 in the present embodiment, the heating line is formed on the side surface (end surface) of the substrate 11, or the corner between the main surface and the side surface is chamfered A heating line may be formed on the chamfered surface. As understood from this, the predetermined surface on which the heat generating portion and the electrode portion are provided is not limited to the main surface of the substrate.

  In the embodiment, the first concave portion is positioned on the common electrode (lead portion) side with respect to the heat generating portion, and the second concave portion is positioned on the individual electrode (connection portion) side with respect to the heat generating portion. It may be. In another aspect, the first recess is located downstream of the heat generating portion in the recording medium conveyance direction (relative movement of the recording medium with respect to the heat generating portion), and the second recess is located upstream of the heat generating portion However, the arrangement may be reversed.

  DESCRIPTION OF SYMBOLS 1: Thermal head, 23a: heating portion, 27c: lead portion (first electrode portion), 29a: connection portion (second electrode portion), 35: protective layer, 53: first concave portion, 55: second concave portion, 57 ... third recess.

Claims (9)

A plurality of heat generating portions arranged in a first direction along the predetermined surface on the predetermined surface;
A plurality of first electrode portions connected to one side of a second direction intersecting the first direction with respect to the plurality of heat generating portions in a plan view of the predetermined surface;
A plurality of second electrode portions connected to the other side of the second direction with respect to the plurality of heat generating portions in a plan view of the predetermined surface;
A protective layer covering the plurality of heat generating portions, the plurality of first electrode portions, and the plurality of second electrode portions;
And have
The protective layer is
A plurality of first recesses positioned between the plurality of first electrode portions in a plan view of the predetermined surface;
A plurality of second recesses positioned between the plurality of second electrode portions in plan view of the predetermined surface;
The thermal head is located between the plurality of heat generating portions in a plan view of the predetermined surface, and has a plurality of third recesses which are shallower than the plurality of first recesses and the plurality of second recesses. . The second direction is orthogonal to the first direction,
The thermal head according to claim 1, wherein the third recess extends in a direction inclined with respect to the second direction in a plan view of the predetermined surface. The thermal head according to claim 1, wherein a part of the third recess is located on an edge of the heat generating portion in the first direction. The thermal head according to any one of claims 1 to 3, wherein a portion on the other side in the second direction of the third recess is connected to the second recess in the second direction. The thermal head according to any one of claims 1 to 4, wherein the portion on the one side in the second direction of the third recess is adjacent to the first recess in the first direction. The thermal head according to claim 5, wherein the sum of the widths in the first direction of the portions adjacent to each other of the first recess and the third recess is larger than the width in the first direction of the second recess. . The said 3rd recessed part contains the part whose width in a said 1st direction is smaller than the width | variety in the said 1st direction of each of a said 1st recessed part and a said 2nd recessed part. Thermal head. A plurality of heat generating portions arranged in a first direction along the predetermined surface on the predetermined surface;
A plurality of first electrode portions connected to one side of a second direction intersecting the first direction with respect to the plurality of heat generating portions in a plan view of the predetermined surface;
A plurality of second electrode portions connected to the other side of the second direction with respect to the plurality of heat generating portions in a plan view of the predetermined surface;
A protective layer covering the plurality of heat generating portions, the plurality of first electrode portions, and the plurality of second electrode portions;
And have
The protective layer is
A plurality of first recesses positioned between the plurality of first electrode portions in a plan view of the predetermined surface;
A plurality of second recesses positioned between the plurality of second electrode portions in plan view of the predetermined surface;
A third portion including a portion adjacent to the plurality of first concave portions and the first direction in a plan view of the predetermined surface, the portion being shallower than the plurality of first concave portions and the plurality of second concave portions; And a recess having a thermal head. The thermal head according to any one of claims 1 to 8.
A transport mechanism for transporting a recording medium onto the thermal head;
A platen roller for pressing the recording medium onto the thermal head;
Has a thermal printer.

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