JP6971751B2 - Thermal head and thermal printer - Google Patents

Description

The present disclosure relates to thermal heads and thermal printers.

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

Japanese Unexamined Patent Publication No. 2002-370397

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

The thermal head according to one aspect of the present disclosure has a plurality of heat generating portions arranged in a first direction along the predetermined surface on a predetermined surface, and the plurality of heat generating portions in a plan view of the predetermined surface. The plurality of first electrode portions connected to one side of the 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. It has a plurality of second electrode portions connected to the above, and a protective layer covering the plurality of heat generating portions, the plurality of first electrode portions, and the plurality of second electrode portions. The layer is located between the plurality of first recesses located between the plurality of first electrode portions in the plan view of the predetermined surface and between the plurality of second electrode portions in the plan view of the predetermined surface. A plurality of third recesses located between the plurality of second recesses and the plurality of heat generating portions in a plan view of the predetermined surface, and shallower than the plurality of first recesses and the plurality of second recesses. And have.

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, the third recess is partially located on the edge of the heat generating portion in the first direction.

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

In one example, the third recess has a portion on one side of the second direction adjacent to the first recess in the first direction.

In one example, the total width of the portions of the first recess and the third recess adjacent to each other in the first direction is larger than the width of the second recess in the first direction.

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

The thermal head according to one aspect of the present disclosure has a plurality of heat generating portions arranged in a first direction along the predetermined surface on a predetermined surface, and the plurality of heat generating portions in a plan view of the predetermined surface. The plurality of first electrode portions connected to one side of the 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. It has a plurality of second electrode portions connected to the above, and a protective layer covering the plurality of heat generating portions, the plurality of first electrode portions, and the plurality of second electrode portions. The layer is located between the plurality of first recesses located between the plurality of first electrode portions in the plan view of the predetermined surface and between the plurality of second electrode portions in the plan view of the predetermined surface. The plurality of second recesses and a portion adjacent to the plurality of first recesses in the plan view of the predetermined surface are included, and the portions include the plurality of first recesses and the plurality of portions. It has a third recess, which is shallower than the second recess of the above.

The thermal printer according to one aspect of the present disclosure includes the thermal head, a transport mechanism for transporting the recording medium on the thermal head, and a platen roller for pressing the recording medium on 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 which shows the schematic structure of the thermal head which concerns on embodiment. It is a top view which shows the structure of the head substrate of the thermal head of FIG. FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 4 (a) and 4 (b) are enlarged perspective views of a part of the head substrate of FIG. It is a top view which shows the protection layer of a head substrate in an enlarged manner. 6 (a), 6 (b) and 6 (c) are cross-sectional views taken along the line VIa-VIa, VIb-VIb and VIc-VIc of FIG. It is a schematic diagram which shows the structure of the thermal printer which has the thermal head of FIG. It is an enlarged perspective view which shows a part of the thermal head which concerns on a modification.

Hereinafter, the thermal head 1 according to the embodiment will be described with reference to the drawings. For convenience, the drawings are provided with an orthogonal coordinate system consisting of the D1 axis, the D2 axis, and the D3 axis. The thermal head 1 may be upward or downward in any direction, but for convenience, a term such as an upper surface may be used with the positive side of the D3 axis as the upper side.

(Overall configuration of 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, thermal paper, and printing is performed by applying heat from the main surface 1a of the thermal head 1 facing the positive side of the D3 axis. Alternatively, for example, the recording medium is a paper other than thermal paper, and printing is performed by applying heat from the main surface 1a of the thermal head 1 to the ink film laminated on the paper to perform thermal transfer. In the following, thermal paper may be taken as an example as a recording medium. Further, the main surface refers to the widest surface (front surface or back surface) of the plate-shaped member.

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

The head substrate 3 has a heating line 3b on the main surface 1a side that applies heat to the thermal paper (or ink film). The heating line 3b is composed of a plurality of heating portions 3c arranged in the D1 direction. Although the boundary of the plurality of heating portions 3c is shown in FIG. 1, the boundary does not always appear in the appearance of the head substrate 3. When the thermal paper slides on the heating line 3b in the D2 direction (strictly speaking, the component in the D3 direction may be contained), the temperature of the plurality of heating portions 3c is individually controlled to form the thermal paper. Any two-dimensional image is formed.

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

The heat sink 5 has a rectangular parallelepiped shape. The heat radiating plate 5 is made of a metal material such as copper, iron, or aluminum, and has a function of radiating heat generated in the heating line 3b of the head substrate 3 that does not contribute to printing. .. The adhesive member 7 adheres the head substrate 3 and the heat sink 5.

The connector 9 electrically connects the head substrate 3 and the external electronic circuit of the thermal head 1. By inputting an electric signal (voltage) from an 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 9a that abut on the plurality of terminals 3d (see FIG. 2) of the head substrate 3. The plurality of pins 9a are, for example, resin-sealed. A flexible printed wiring board (FPC) may be used instead of the connector 9 having such a configuration.

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

The head substrate 3 has a substrate 11 and various layers laminated on the surface thereof. Hereinafter, each member constituting the head substrate 3 will be described.

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

(Reinforcing conductor layer)
A reinforcing conductor layer 13 (FIG. 3) is provided on the substrate 11. The reinforcing conductor layer 13 has the same effect as, for example, overlapping with a common electrode 27 or the like, which will be described later, to make the electrode thicker, and thus contributes to reducing the wiring resistance. The position in the plan view may be appropriately set. The material of the reinforcing conductor layer 13 may be an appropriate metal, for example, silver (Ag) or copper (Cu) or an alloy thereof. The reinforcing conductor layer 13 is formed by, for example, 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 to the upper surface of the substrate 11 by screen printing or the like and firing the paste. It is formed.

(Glaze layer)
A glaze layer 15 (FIG. 3) is provided on the substrate 11 (from above the reinforcing conductor layer 13 at the arrangement position). The glaze layer 15 has a first glaze 17 that constitutes the inner side of the heating line 3b, and a second glaze 19 that is separated from the first glaze 17 and extends over a relatively wide range. The first glaze 17 contributes to, for example, heat storage and / or to appropriately shape the surface of the heating line 3b. By forming the second glaze 19 flatter than the surface of the substrate 11, for example, the risk of disconnection and / or short circuit of the conductive layer formed on the second glaze 19 is reduced.

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

The cross-sectional shape of the first glaze 17 may be, for example, a flat upper surface (for example, a rectangle or a trapezoid) in addition to the dome shape, or a shape protruding from a shape that can be conceived as a dome shape (for example, above). The bottom may be a flat or curved frustum shape), or the dome-shaped upper surface may have a protrusion protruding from the upper surface (two-stage shape).

Since the surface of the first glaze 17 is a curved surface, the layer on the first glaze 17 is also curved. In the following, when the layer on the first glaze 17 has a planar shape (sometimes simply referred to as a shape), it means, for example, a shape seen 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 thicknesses of the first glaze 17 and the second glaze 19 may be appropriately set. 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 printing a predetermined glass paste obtained by mixing a glass powder with an appropriate organic solvent and then firing the glass paste.

(Underground layer)
An underlayer 21 (FIG. 3) is provided on the glaze layer 15. The base layer 21 contributes to reducing the possibility that the layer below the base layer 21 is etched when the layer above the base layer 21 is etched, for example, in the manufacturing process of the head base 3. The base 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-arranged region of the glaze layer 15.

The base layer 21 can be formed by a thin film forming technique such as sputtering using a material such as SiC, SiC, or SiALON. 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 base layer 21 does not necessarily have to be provided.

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

The overall planar shape (pattern) of the heating element layer 23 is the same as the planar shape of the conductive layer 25 described later, except for, for example, a plurality of heat generating portions 23a. The heating element layer 23 may be composed of only a plurality of heat generating portions 23a, or only the heat generating portion 23a and its surrounding portions. The thickness of the heating element layer 23 may be appropriately set, and is, for example, 0.01 μm or more and 0.5 μm or less.

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

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

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

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

The common electrode 27 is commonly connected to the plurality of heat generating portions 23a, and imparts the same potential to each other to the plurality of heat generating portions 23a. The plurality of individual electrodes 29 are separately (for example, separately) connected to the plurality of heat generating portions 23a, and independently apply potential to the plurality of heat generating portions 23a. As a result, voltages are independently 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 a plan view, and any image can be printed.

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

The plurality of wirings 31 are responsible for the connection between the drive IC 45 and the connector 9, or the connection between the plurality of drive ICs 45, and contribute to inputting a signal corresponding to the content of the 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 an appropriate metal such as aluminum (Al) or an aluminum alloy. The thickness may be appropriately set, and is, for example, 0.5 μm or more and 2.0 μm or less. The conductive layer 25 is formed by forming a thin film by, for example, a thin film forming technique such as a sputtering method, and then processing the thin film into a predetermined pattern by using photoetching or the like. The etching may be performed in two steps, that is, a step of etching both the heating element layer 23 and the conductive layer 25, and then a step of etching the conductive layer 25 directly above the heat generating portion 23a.

(Common electrode)
As indicated by reference numerals in FIG. 2, the common electrode 27 is a main wiring portion located on the side opposite to the terminal side (+ D2) of the head substrate 3 with respect to the plurality of heat generating portions 23a (first glaze 17). It has a 27a, an auxiliary 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 extends linearly with a constant width along the first glaze 17, for example, at a position not overlapping the first glaze 17.

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

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

(Individual electrode)
The plurality of individual electrodes 29 are provided, for example, on a one-to-one basis with respect to the plurality of heat generating portions 23a. Further, for example, the plurality of individual electrodes 29 extend from the center side of the substrate 11 to the first glaze 17 side while gradually increasing the width and pitch. After that, the plurality of individual electrodes 29 (of which the connecting portion 29a) extend linearly with a constant width along the D2 direction (for example, in parallel) and are connected to the −D2 side of the plurality of heat generating portions 23a. There is. The entire connection portion 29a may be located on the first glaze 17, or a part of the tip end side may be located on the first glaze 17. In addition, unlike the illustrated example, two or more heat generating portions 23a adjacent to each other may be connected to one individual electrode 29. The ends of the plurality of individual electrodes 29 on the opposite side of the plurality of heat generating portions 23a constitute a pad 3e (FIG. 2) for surface mounting the drive IC 45.

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

The ground electrode 33 is formed in a solid shape in a region surrounded by, for example, an individual electrode 29, a common electrode 27, and a plurality of wirings 31. A part of the ground electrode 33 constitutes a pad 3e on which the drive IC 45 is surface-mounted, and a part of the other portion 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. Note that FIG. 2 omits the illustration of the protective layer 35. The protective layer 35 contributes to, for example, suppressing wear of the heating element layer 23 and the conductive layer 25 due to contact with the recording medium, and oxidation / corrosion of these layers.

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

The protective layer 35 can be formed by using SiN, SiO, SiON, SiC, SiCN, diamond-like carbon, or the like. The protective layer 35 may be configured as a single layer as in the present embodiment, or may be configured by laminating a plurality of layers. The protective layer 35 can be produced by 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 appropriately set, but is, for example, thicker than the total thickness of the heating element layer 23 and the conductive layer 25, and 3 μm or more and 20 μm or less.

(Coating layer)
A covering layer 37 (FIG. 3) is provided in the non-arranged region of the protective layer 35. In FIG. 2, the covering layer 37 is not shown. Further, the covering layer 37 may overlap a part of the protective layer 35. The coating layer 37 contributes to, for example, insulating the conductive layer 25 from the outside of the head substrate 3 and suppressing oxidation / corrosion of the conductive layer 25.

The coating layer 37 is provided on substantially the entire surface of the substrate 11, for example, while exposing the heating lines 3b, the plurality of pads 3e, and the plurality of terminals 3d. The thickness of the coating layer is 5 μm or more and 30 μm or less. The material of the coating layer 37 is a resin material such as an epoxy resin, a polyimide resin, or a silicone resin. The coating layer 37 is formed, for example, by 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 a plurality of pads 3e via bumps (not shown) and sealed by a 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)
4 (a) and 4 (b) are enlarged perspective views showing a part of the head substrate 3. In FIG. 4A, the illustration of the protective layer 35 is omitted with respect to 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. A connecting portion 29a of the individual electrode 29 is connected to the −D2 side of each heat generating portion 23a.

The lead portion 27c, the heat generating portion 23a, and the connecting portion 29a form, for example, a ridge (reference numeral omitted) extending linearly with a constant width along the D2 direction as a whole as a whole. doing. From 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 heating element layer 23 is the same as the pattern of the conductive layer 25 (common electrode 27 and individual electrode 29) except for the heat generating portion 23a. Therefore, the lower groove 51 has a depth corresponding to the total thickness of the heating element layer 23 and the conductive layer 25 at the positions between the plurality of lead portions 27c and between the plurality of connecting portions 29a. ing.

In the protective layer 35 that overlaps the protective layer 35, the first recess 53, the second recess 55, and the third recess 57 are formed at positions that substantially overlap the lower groove 51. The first recess 53 is a recess in which at least a part is located between the lead portions 27c adjacent to each other in a plan view. The second recess 55 is a recess in which at least a part of the second recess 55 is located between the connecting portions 29a adjacent to each other in a plan view. The third recess 57 is a recess in which at least a part is located between the heat generating portions 23a adjacent to each other in a plan view.

Although not particularly shown, the protective layer 35 may have a recess that substantially overlaps with the heat generating 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 shallower, about the same, or deeper than the depth of the third recess 57.

FIG. 5 is an enlarged plan view showing the upper surface of the protective layer 35. In this figure, the lead portion 27c, the heat generating portion 23a, and the connecting portion 29a are also shown by dotted lines. Further, the heat generating portion 23a is provided with hatching. 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.

(1st recess and 2nd recess)
Each of the first recess 53 and the second recess 55 is, for example, a concave groove extending linearly with a constant width parallel to the D2 direction in a plan view. In the concave groove, the end portion opposite to the heat generating portion 23a may be located on the first glaze 17, or may be located on the long side (edge portion) of the first glaze 17. However, it may be located outside the first glaze 17 (example in the figure). Further, the end portion on the heat generation portion 23a side may be located on the first glaze 17 on the premise that the end portion on the heat generation portion 23a side is located closer to the heat generation portion 23a than the end portion on the opposite side to the heat generation portion 23a. (Example in the figure), it 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. Further, the end portion on the heat generating portion 23a side may reach the position of the heat generating portion 23a in the D2 direction, or may be located outside the heat generating portion 23a (illustration example).

The cross-sectional shape of each 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, and is, for example, a substantially rectangular shape. Or, for example, the cross-sectional shape is a shape in which the width becomes narrower toward the bottom side over the entire depth direction or from an appropriate depth on the bottom side. The width and 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 regardless of the position in the D2 direction, for example. When the first recess 53 or the second recess 55 has a portion located on the first glaze 17, the cross-sectional shape of the portion becomes shallower, for example, as the upper portion of the groove is shaved as it approaches the heat generating portion 23a side. (For example, the protective layer 35 may be thin). In addition, in FIG. 4 (b) and FIG. 5, the edge portion of the first recess 53 and the second recess 55 on the apex side of the first glaze 17 is clearly shown, but these recesses are the apex of the first glaze 17. The closer to, the shallower it becomes, and the edge on the apex side may be unclear.

The width w1 (FIG. 6A) of the first recess 53 depends on the film forming state of the protective layer 35, but is, for example, substantially the same as the distance between the lead portions 27c. Similarly, the width w2 (FIG. 6 (c)) of the second recess 55 is substantially the same as the distance between the connecting portions 29a, although it depends on the film forming state of the protective layer 35. The widths w1 and w2 are, for example, the same size as each other. The width of the recess (53, 55, 57, etc.) 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.

The depth d1 of the first recess 53 (FIG. 6A) and the depth d2 of the second recess 55 depend on the film forming state of the protective layer 35, but for example, the total of the heating element layer 23 and the conductive layer 25. It is less than or equal to the thickness. The depths d1 and d2 are, for example, of equal magnitude to each other. The depth of the recess (53, 55, 57, etc.) 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, when the protective layer 35 has a curved surface as in the present embodiment, the depth may be specified in the normal direction, or when the curvature is relatively small, it is specified in the D3 direction. May be 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 linearly with a constant width in a direction generally inclined in the D2 direction in a plan view. In the concave groove, the end portion on the second concave portion 55 side is connected to, for example, the end portion of the second concave portion 55 in the D2 direction. Further, the end portion on the first concave portion 53 side is adjacent to the first concave portion 53 in the D1 direction, for example.

When the second recess 55 and the third recess 57 are connected in the D2 direction, for example, the amount of overlap between the second recess 55 and the third recess 57 in the D1 direction at the connected positions is the same as that of the third recess 57 of the second recess 55. It may include a state of 70% or more of the length in the D1 direction in the portion immediately before the connection and / or 70% or more of the length of the third recess 57 in the D1 direction immediately before the connection with the second recess 55.

Further, when the first recess 53 and the third recess 57 are adjacent to each other in the D1 direction, for example, they are separated from each other on the premise that a part of the arrangement range in the D2 direction of both overlaps with each other. In the case where both are connected (example in the figure), the amount of overlap in the D1 direction at the connected position is immediately before overlapping with the third recess 57 of the first recess 53. It may include a state in which the length of the portion is less than 30% in the D1 direction and the length of the third recess 57 is less than 30% of the length in the D1 direction immediately before overlapping with the second recess 55.

Since 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 heat generating portion 23a side of the second recess 55 described above is connected. The description of the end position of the third recess 57 may be taken as an explanation of the end position of the third recess 57 on the second recess 55 side. That is, the end portion of the third recess 57 on the second recess 55 side may be located on the first glaze 17 (example in the figure), or the edge portion (long side) of the first glaze 17 on the −D2 side. ), Or it may be located outside (-D2 side) of the first glaze 17. Further, the end portion of the third recess 57 on the second recess 55 side may be contained within the range of the heat generating portion 23a in the D2 direction, or is located outside (−D2 side) of the heat generating portion 23a. It may be (example shown in the figure).

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

Since the third recess 57 is inclined in a plan view, for example, a part of the third recess 57 is located between the heat generating portions 23a, but the other part overlaps with the heat generating portion 23a. More specifically, the third recess 57 is located on the edge portion (at least a part thereof) on the −D2 side of the heat generating portion 23a. The area ratio of the portion of the third recess 57 located between the heat generating portion 23a and the portion located on the heat generating portion 23a, or the ratio of the area where the third recess 57 overlaps the heat generating portion 23a to the area of the heat generating portion 23a is determined. It may be set as appropriate. For example, the ratio of the area where 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 shown, the third recess 57 does not have to overlap the heat generating portion 23a.

The cross-sectional shape of the third recess 57 (the shape of the cross section orthogonal to the D2 axis; the same applies hereinafter) may be an appropriate shape, and is, for example, a substantially rectangular shape. Or, for example, the cross-sectional shape is a shape in which the width becomes narrower toward the bottom side over the entire depth direction or from an appropriate depth on the bottom side. The width and depth of the third recess 57 may be larger than the other, and in the example shown in FIG. 6B, the depth d3 is smaller than the width w3. At least a part (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 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. 6 (b); here, the length in the D1 direction) is substantially the same as, for example, the width w1 of the first recess 53 and / or the width w2 of the second recess 55. be. For example, the difference between the width w3 and the width w1 or w2 is less than 20% of the latter.

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

In the region where the range in the D2 direction overlaps with each other in the first recess 53 and the third recess 57, the relatively deep portion (the portion having the depth d1) is a part of the first recess 53 and is relative. The shallow portion (the portion having a depth d3) is a part of the third recess 57. Therefore, as shown in FIG. 6A, when the portion of the third recess 57 adjacent to the first recess 53 is connected to the first recess 53 in the D1 direction, the width w4 of the portion (a). Here, the length in the D1 direction is used.) Is narrower than the width w3 of the other portion of the third recess 57. As a result, for example, the width w4 becomes 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. Further, the methods for forming various layers on the substrate 11 have already been mentioned. For example, when the protective layer 35 is formed, the first recess 53 and the second recess 55 are partially formed in the lower groove 51 as if a part of the protective layer 35 was depressed by the lower groove 51. It is formed by

The third recess 57 may be formed by an appropriate method. For example, although not particularly shown, after the head substrate 3 is produced by a known method as described above, the head substrate 3 is conveyed to the −D1 side, and the second recess 55 is moved to the + D2 side by the fixed abrasive grains. Polish with a width of 55. As a result, a third recess 57 that is relatively shallow and has a width equivalent to that of the second recess 55 and extends toward the + D2 side while being inclined toward the + D1 side is formed.

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

The thermal printer 101 includes a thermal head 1, a transfer mechanism 103 that conveys a recording medium P (using thermal paper as an example), a platen roller 105 that presses the recording medium P against a heating line 3b, and a power supply that supplies electric power to these. It includes a device 107 and a control device 109 that controls these operations.

The thermal head 1 is attached to the attachment surface 111a of the attachment member 111 provided in the housing (not shown) of the thermal printer 101. The thermal head 1 is attached to the mounting member 111 so as to be along the main scanning direction (D1 axial direction) which is a direction orthogonal to the transport direction S of the recording medium P.

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

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

The platen roller 105 is arranged so as to extend along a direction orthogonal to the transport direction S of the recording medium P, and both ends thereof are supported and fixed so as to be rotatable while the recording medium P is pressed onto the heat generating portion 23a. ing. The platen roller 105 can be configured by, for example, covering a columnar shaft body 105a made of a 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 heat generating portion 23a 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 selectively generate heat of the heat generation unit 23a of the thermal head 1.

The thermal printer 101 presses the recording medium P onto the heat generating portion 23a of the thermal head 1 by the platen roller 105, and conveys the recording medium P onto the heat generating portion 23a by the conveying mechanism 103, while the power supply device 107 and the control device 109. By selectively generating heat from the heat generating portion 23a, a predetermined printing is performed on the recording medium P. When the recording medium P is an image receiving paper or the like, the ink of the ink film (not shown) conveyed together with the recording medium P is thermally transferred to the recording medium P to print on the recording medium P.

As described above, in the present embodiment, the thermal head 1 includes a plurality of heat generating portions 23a, a plurality of first electrode portions (lead portions 27c), a plurality of second electrode portions (connection portions 29a), and a protective layer 35. And have. The plurality of heat generating portions 23a are arranged on a predetermined surface (for example, the main surface of the substrate 11 or the base layer 21) in the first direction (D1 direction) along the main surface of the substrate 11. The plurality of lead portions 27c are connected to one side (+ D2 side) of the second direction (D2 direction) intersecting the plurality of heat generating portions 23a in the D1 direction in a plan view. The plurality of connecting 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 a plan view. The protective layer 35 covers a plurality of heat generating portions 23a, a plurality of lead portions 27c, and a plurality of connecting portions 29a. Further, the protective layer 35 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 27c in a plan view. The plurality of second recesses 55 are located between the plurality of connecting portions 29a in a plan view. The plurality of third recesses 57 are located between the plurality of heat generating portions 23a in a 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 recess 57 is located between the heat generating portions 23a, the possibility that the recording medium or the ink film sticks to the region on the heat generating portion 23a of the protective layer 35 (sticking occurs) is reduced. NS. On the other hand, since the third recess 57 is relatively shallow, for example, dust such as paper dust (paper dust) generated by sliding is easily discharged from the third recess 57. As a result, for example, the possibility that the characteristics related to heating are changed by the dust accumulated in the third recess 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 a plan view.

Therefore, for example, focusing on a linear region parallel to the D1 direction in the recording medium, when the region is sliding in the D2 direction with respect to the head substrate 3, the contact position with respect to the protective layer 35 (conversely). Speaking of which, the position directly above the third recess 57) changes in the D1 direction as it slides. 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 recess 57 is located on the edge portion of the heat generating portion 23a in the D1 direction (−D1 side).

Therefore, for example, the effect of suppressing sticking can be obtained at the edge portion 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 particularly smooth on the heat generating portion 23a, and by extension, the spacing between dots in the D1 direction on the recording medium is stable. That is, the image quality is improved.

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

Therefore, for example, dust such as paper scraps that have 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 with the case where the dust is directly discharged to the outside from the second recess 55. This effect is further enhanced when the second recess 55 is located on the upstream side of the relative movement of the recording medium with respect to the third recess 57 with respect to the third recess 57.

Further, in the present embodiment, the portion of the third recess 57 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 total width (w1 + w4) of the portions 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 further reducing the contact area between the recording medium and the protective layer 35 and the action of changing the contact state with the sliding of the recording medium are exhibited, and the effect of suppressing sticking is further enhanced.

Further, in the present embodiment, the width of the third recess 57 in the D1 direction includes a portion (for example, a portion having 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, the third recess 57 itself is made thinner while reducing the contact area between the recording medium and the protective layer 35 by the third recess 57. This facilitates, for example, arranging the third recess 57 at an appropriate position in a necessary and sufficient area.

This embodiment can be grasped from a viewpoint different from the viewpoint that the third recess 57 is located between the heat generating portions 23a in a plan view and is shallower than the first recess 53 and the second recess 55. For example, the third recess 57 is adjacent to the first recess 53 in the D1 direction in a plan view, and is shallower than the first recess 53 and the second recess 55.

From this point of view, for example, the third recess 57 can substantially expand the first recess 53 in the D1 direction to reduce the risk of sticking. On the other hand, since the third recess 57 is relatively shallow, dust such as paper scraps is likely to be discharged.

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

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

Also in this modification, for example, the first divided recess 57a is adjacent to the first recess 53 in the D1 direction in a plan view, like the third recess 57 of the embodiment, and the first recess 53 and the second recess 55 are adjacent to each other. Since it is shallower than that, the same effect as that of the embodiment is obtained. For example, the third recess 57 can substantially expand the first recess 53 in the D1 direction to reduce the risk of sticking. On the other hand, since the third recess 57 is relatively shallow, dust such as paper scraps is likely to be discharged.

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

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

For example, in the present embodiment, the embodiment in which the heating line 3b is provided on the main surface of the substrate 11 is exemplified, but the heating line is formed on the side surface (end surface) of the substrate 11 or the corner portion between the main surface and the side surface is chamfered. A heating line may be formed on the chamfered surface. As can be 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 recess is located on the common electrode (lead portion) side with respect to the heat generating portion, and the second recess is located on the individual electrode (connecting portion) side with respect to the heat generating portion, but the arrangement is reversed. There may be. From another viewpoint, the first recess was located downstream of the heat generating portion in the transport direction of the recording medium (relative movement of the recording medium with respect to the heat generating portion), and the second recess was located upstream of the heat generating portion. However, the arrangement may be reversed.

1 ... Thermal head, 23a ... Heat generation part, 27c ... Lead part (first electrode part), 29a ... Connection part (second electrode part), 35 ... Protective layer, 53 ... First recess, 55 ... Second recess, 57 … Third recess.

Claims (9)

A plurality of heat generating portions arranged in the first direction along the predetermined surface on the predetermined surface, and
In a plan view of the predetermined surface, a plurality of first electrode portions connected to one side of the second direction intersecting the plurality of heat generating portions in the first direction.
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, and a plurality of second electrode portions.
A protective layer covering the plurality of heat generating portions, the plurality of first electrode portions, and the plurality of second electrode portions.
Have and
The protective layer is
A plurality of first recesses located between the plurality of first electrode portions in a plan view of the predetermined surface,
A plurality of second recesses located between the plurality of second electrode portions in a plan view of the predetermined surface,
It is located between the plurality of heat generating portions in a plan view of the predetermined surface, and has a plurality of first recesses and a plurality of third recesses shallower than the plurality of second recesses .
The surface of the protective layer is a thermal head having a curved surface bulging outward over the first electrode portion, the heat generating portion, and the second electrode connected to each other. A plurality of heat generating portions arranged in the first direction along the predetermined surface on the predetermined surface, and
In a plan view of the predetermined surface, a plurality of first electrode portions connected to one side of the second direction intersecting the plurality of heat generating portions in the first direction.
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, and a plurality of second electrode portions.
A protective layer covering the plurality of heat generating portions, the plurality of first electrode portions, and the plurality of second electrode portions.
Have and
The protective layer is
A plurality of first recesses located between the plurality of first electrode portions in a plan view of the predetermined surface,
A plurality of second recesses located between the plurality of second electrode portions in a plan view of the predetermined surface,
It is located between the plurality of heat generating portions in a plan view of the predetermined surface, and has a plurality of first recesses and a plurality of third recesses shallower than the plurality of second recesses.
The second direction is orthogonal to the first direction and is orthogonal to the first direction.
The third recess extends in a direction inclined with respect to the second direction in a plan view of the predetermined surface.
Sa Maruheddo. A plurality of heat generating portions arranged in the first direction along the predetermined surface on the predetermined surface, and
In a plan view of the predetermined surface, a plurality of first electrode portions connected to one side of the second direction intersecting the plurality of heat generating portions in the first direction.
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, and a plurality of second electrode portions.
A protective layer covering the plurality of heat generating portions, the plurality of first electrode portions, and the plurality of second electrode portions.
Have and
The protective layer is
A plurality of first recesses located between the plurality of first electrode portions in a plan view of the predetermined surface,
A plurality of second recesses located between the plurality of second electrode portions in a plan view of the predetermined surface,
It is located between the plurality of heat generating portions in a plan view of the predetermined surface, and has a plurality of first recesses and a plurality of third recesses shallower than the plurality of second recesses.
The third recess is partially located on the edge of the heat generating portion in the first direction.
Sa Maruheddo. A plurality of heat generating portions arranged in the first direction along the predetermined surface on the predetermined surface, and
In a plan view of the predetermined surface, a plurality of first electrode portions connected to one side of the second direction intersecting the plurality of heat generating portions in the first direction.
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, and a plurality of second electrode portions.
A protective layer covering the plurality of heat generating portions, the plurality of first electrode portions, and the plurality of second electrode portions.
Have and
The protective layer is
A plurality of first recesses located between the plurality of first electrode portions in a plan view of the predetermined surface,
A plurality of second recesses located between the plurality of second electrode portions in a plan view of the predetermined surface,
It is located between the plurality of heat generating portions in a plan view of the predetermined surface, and has a plurality of first recesses and a plurality of third recesses shallower than the plurality of second recesses.
In the third recess, a portion on one side of the second direction is adjacent to the first recess in the first direction.
Sa Maruheddo. The thermal head according to claim 4 , wherein the total width of the portions of the first recess and the third recess adjacent to each other in the first direction is larger than the width of the second recess in the first direction. .. A plurality of heat generating portions arranged in the first direction along the predetermined surface on the predetermined surface, and
In a plan view of the predetermined surface, a plurality of first electrode portions connected to one side of the second direction intersecting the plurality of heat generating portions in the first direction.
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, and a plurality of second electrode portions.
A protective layer covering the plurality of heat generating portions, the plurality of first electrode portions, and the plurality of second electrode portions.
Have and
The protective layer is
A plurality of first recesses located between the plurality of first electrode portions in a plan view of the predetermined surface,
A plurality of second recesses located between the plurality of second electrode portions in a plan view of the predetermined surface,
It is located between the plurality of heat generating portions in a plan view of the predetermined surface, and has a plurality of first recesses and a plurality of third recesses shallower than the plurality of second recesses.
The third recess includes a portion whose width in the first direction is smaller than the width of each of the first recess and the second recess in the first direction.
Sa Maruheddo. The thermal head according to any one of claims 1 to 6 , wherein the third recess is a portion of the other side in the second direction connected to the second recess in the second direction. A plurality of heat generating portions arranged in the first direction along the predetermined surface on the predetermined surface, and
In a plan view of the predetermined surface, a plurality of first electrode portions connected to one side of the second direction intersecting the plurality of heat generating portions in the first direction.
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, and a plurality of second electrode portions.
A protective layer covering the plurality of heat generating portions, the plurality of first electrode portions, and the plurality of second electrode portions.
Have and
The protective layer is
A plurality of first recesses located between the plurality of first electrode portions in a plan view of the predetermined surface,
A plurality of second recesses located between the plurality of second electrode portions in a plan view of the predetermined surface,
A third recess that includes a portion adjacent to the plurality of first recesses in the first direction in a plan view of the predetermined surface, and the portion is shallower than the plurality of first recesses and the plurality of second recesses. With a recess, the thermal head has. The thermal head according to any one of claims 1 to 8,
A transport mechanism that transports the recording medium onto the thermal head,
A platen roller that presses the recording medium onto the thermal head,
Have a thermal printer.

Images