JP7036692B2 - Thermal head and thermal printer - Google Patents

Description

The present disclosure relates to thermal heads and thermal printers.

Conventionally, various thermal heads have been proposed as printing devices such as facsimiles and video printers. For example, a substrate, a heat generating portion located on the substrate, an electrode located on the substrate and connected to the heat generating portion, and a first protective layer covering the heat generating portion and a part of the electrode. It is known that a second protective layer located on the first protective layer is provided (see Patent Document 1).

Jikkenhei 8-1155 Gazette

The thermal head of the present disclosure includes a substrate, a heat generating portion, electrodes, a first protective layer, and a second protective layer. The heat generating portion is located on the substrate. The electrodes are located on the substrate and are connected to the heat generating part. The first protective layer covers the heat generating portion and a part of the electrode. The second protective layer is located on the first protective layer. The first protective layer contains the first crystal particles. The average crystal grain size of the second crystal particles including the second crystal particles is larger than the average crystal grain size of the first crystal particles.

The thermal printer of the present disclosure includes the thermal head described above, a transport mechanism for transporting a recording medium onto the heat generating portion, and a platen roller for pressing the recording medium.

FIG. 1 is an exploded perspective view showing an outline of the thermal head according to the first embodiment. FIG. 2 is a plan view showing an outline of the thermal head shown in FIG. FIG. 3 is a cross-sectional view taken along the line III-III of FIG. FIG. 4 is an enlarged cross-sectional view showing the vicinity of the protective layer of the thermal head shown in FIG. FIG. 5 is a schematic view showing a thermal printer according to the first embodiment.

In the conventional thermal head, in order to improve the reliability of the protective layer, the thermal head includes a first protective layer that covers a part of the heat generating portion and the electrode, and a second protective layer located on the first protective layer. It has been known. Nowadays, it is required to further improve the reliability of the protective layer.

The thermal head of the present disclosure can improve the reliability of the protective layer. Hereinafter, the thermal head of the present disclosure and the thermal printer using the same will be described in detail.

<First Embodiment>
The thermal head X1 will be described with reference to FIGS. 1 to 4. FIG. 1 schematically shows the configuration of the thermal head X1. In FIG. 2, the protective layer 25, the covering layer 27, and the sealing member 12 are shown by a alternate long and short dash line, and the covering member 29 is shown by a broken line. FIG. 3 is a cross-sectional view taken along the line III-III of FIG. In FIG. 3, the layer structure of the protective layer 25 is omitted. FIG. 4 shows an enlarged view of the vicinity of the protective layer 25 of the thermal head X1.

The thermal head X1 includes a head substrate 3, a connector 31, a sealing member 12, a heat sink 1, and an adhesive member 14. The connector 31, the sealing member 12, the heat sink 1, and the adhesive member 14 do not necessarily have to be provided.

The heat radiating plate 1 dissipates excess heat from the head substrate 3. The head substrate 3 is placed on the heat radiating plate 1 via the adhesive member 14. The head substrate 3 prints on the recording medium P (see FIG. 5) by applying a voltage from the outside. The adhesive member 14 adheres the head substrate 3 and the heat sink 1. The connector 31 electrically connects the head substrate 3 to the outside. The connector 31 has a connector pin 8 and a housing 10. The sealing member 12 joins the connector 31 and the head substrate 3.

The heat sink 1 has a rectangular parallelepiped shape. The heat radiating plate 1 is made of a metal material such as copper, iron, or aluminum, and dissipates heat that does not contribute to printing among the heat generated in the heat generating portion 9 of the head substrate 3.

The head substrate 3 has a rectangular shape in a plan view, and each member constituting the thermal head X1 is arranged on the substrate 7. The head substrate 3 has a function of printing on the recording medium P according to an electric signal supplied from the outside.

Each member constituting the head substrate 3, the sealing member 12, the adhesive member 14, and the connector 31 will be described with reference to FIGS. 1 to 3.

The head substrate 3 includes a substrate 7, a heat storage layer 13, an electric resistance layer 15, a common electrode 17, an individual electrode 19, a first connection electrode 21, a connection terminal 2, a conductive member 23, and a drive IC ( It has an Integrated Circuit) 11, a covering member 29, a protective layer 25, and a covering layer 27. It should be noted that these members do not necessarily have to be all provided. Further, the head substrate 3 may include members other than these. The protective layer 25 is a general term for the first protective layer 25a and the second protective layer 25b, which will be described later.

The substrate 7 is arranged on the heat radiating plate 1 and has a rectangular shape in a plan view. The substrate 7 has a first surface 7f, a second surface 7g, and a side surface 7e. The first surface 7f has a first long side 7a, a second long side 7b, a first short side 7c, and a second short side 7d. Each member constituting the head substrate 3 is arranged on the first surface 7f. The second surface 7g is located on the opposite side of the first surface 7f. The second surface 7g is located on the heat sink 1 side and is joined to the heat sink 1 via the adhesive member 14. The side surface 7e connects the first surface 7f and the second surface 7g, and is located on the second long side 7b side.

The substrate 7 is formed of, for example, an electrically insulating material such as alumina ceramics or a semiconductor material such as single crystal silicon.

The heat storage layer 13 is located on the first surface 7f of the substrate 7. The heat storage layer 13 rises upward from the first surface 7f. In other words, the heat storage layer 13 projects in a direction away from the first surface 7f of the substrate 7.

The heat storage layer 13 is arranged so as to be adjacent to the first long side 7a of the substrate 7, and extends along the main scanning direction. Since the cross section of the heat storage layer 13 has a substantially semi-elliptical shape, the protective layer 25 formed on the heat generating portion 9 comes into good contact with the recording medium P to be printed. As the height of the heat storage layer 13 from the first surface 7f of the substrate 7, 30 to 60 μm can be exemplified.

The heat storage layer 13 is made of glass having low thermal conductivity, and temporarily stores a part of the heat generated in the heat generating portion 9. Therefore, the time required to raise the temperature of the heat generating portion 9 can be shortened, and the thermal response characteristics of the thermal head X1 can be improved.

The heat storage layer 13 is formed by, for example, applying a predetermined glass paste obtained by mixing a glass powder with an appropriate organic solvent onto the first surface 7f of the substrate 7 by screen printing or the like and firing the paste.

The electric resistance layer 15 is located on the upper surface of the heat storage layer 13, and a common electrode 17, an individual electrode 19, a first connection electrode 21, and a second connection electrode 26 are formed on the electric resistance layer 15. An exposed region where the electric resistance layer 15 is exposed is formed between the common electrode 17 and the individual electrode 19. As shown in FIG. 2, the exposed regions of the electric resistance layer 15 are arranged in a row on the heat storage layer 13, and each exposed region constitutes a heat generating portion 9.

The electric resistance layer 15 does not necessarily have to be located between the various electrodes and the heat storage layer 13, and the common electrode 17 and the individual electrode 19 are, for example, so as to electrically connect the common electrode 17 and the individual electrode 19. It may be located only between 19 and 19.

Although the plurality of heat generating portions 9 are simplified and described in FIG. 2 for convenience of explanation, they are arranged at a density of, for example, 100 dpi to 2400 dpi (dot per inch). The electric resistance layer 15 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 9, the heat generating portion 9 generates heat due to Joule heat generation.

The common electrode 17 includes a main wiring portion 17a and 17d, a sub wiring portion 17b, and a lead portion 17c. The common electrode 17 electrically connects the plurality of heat generating portions 9 and the connector 31. The main wiring portion 17a extends along the first long side 7a of the substrate 7. The sub-wiring portion 17b extends along each of the first short side 7c and the second short side 7d of the substrate 7. The lead portion 17c individually extends from the main wiring portion 17a toward each heat generating portion 9. The main wiring portion 17d extends along the second long side 7b of the substrate 7.

The plurality of individual electrodes 19 are electrically connected between the heat generating portion 9 and the drive IC 11. Further, the plurality of heat generating units 9 are divided into a plurality of groups, and the heat generating units 9 of each group and the drive IC 11 arranged corresponding to each group are electrically connected by individual electrodes 19.

The plurality of first connection electrodes 21 are electrically connected between the drive IC 11 and the connector 31. The plurality of first connection electrodes 21 connected to each drive IC 11 are composed of a plurality of wirings having different functions.

The plurality of second connection electrodes 26 electrically connect the adjacent drive ICs 11. The plurality of second connection electrodes 26 are composed of a plurality of wirings having different functions.

The common electrode 17, the individual electrode 19, the first connection electrode 21, and the second connection electrode 26 are made of a conductive material, and are, for example, any one of aluminum, gold, silver, and copper. Formed from metals or alloys of these.

The plurality of connection terminals 2 are arranged on the second long side 7b side of the first surface 7f in order to connect the common electrode 17 and the first connection electrode 21 to the FPC 5. The connection terminal 2 is arranged corresponding to the connector pin 8 of the connector 31, which will be described later.

A conductive member 23 is provided on each connection terminal 2. As the conductive member 23, for example, solder, ACP (Anisotropic Conducive Paste), or the like can be exemplified. A plating layer made of Ni, Au, or Pd may be arranged between the conductive member 23 and the connection terminal 2.

For the various electrodes constituting the head substrate 3, the metal material layers such as Al, Au, and Ni constituting each of them are sequentially laminated on the heat storage layer 13 by a thin film forming technique such as a sputtering method to form a laminated body. Form. Next, the laminate can be formed by processing it into a predetermined pattern using a technique such as photoetching. The various electrodes constituting the head substrate 3 can be simultaneously formed by the same process.

As shown in FIG. 2, the drive IC 11 is arranged corresponding to each group of the plurality of heat generating portions 9. Further, the drive IC 11 is connected to the individual electrode 19 and the first connection electrode 21. The drive IC 11 has a function of controlling the energized state of each heat generating portion 9. A switching IC can be used as the drive IC 11.

The protective layer 25 covers a part of the heat generating portion 9, the common electrode 17, and the individual electrode 19. The protective layer 25 is for protecting the covered area from corrosion due to adhesion of moisture and the like contained in the atmosphere, or wear due to contact with the recording medium P to be printed.

The coating layer 27 is arranged on the substrate 7 so as to partially cover the common electrode 17, the individual electrode 19, the first connection electrode 21, and the second connection electrode 26. The covering layer 27 is for protecting the covered region from oxidation due to contact with the atmosphere or corrosion due to adhesion of moisture or the like contained in the atmosphere. The coating layer 27 can be formed of a resin material such as an epoxy resin, a polyimide resin, or a silicone resin.

The drive IC 11 is sealed with a coating member 29 made of a resin such as an epoxy resin or a silicone resin in a state of being connected to the individual electrode 19, the first connection electrode 21, and the second connection electrode 26. The covering member 29 is arranged so as to extend in the main scanning direction, and integrally seals a plurality of drive ICs 11.

The connector 31 has a plurality of connector pins 8 and a housing 10 for accommodating the plurality of connector pins 8. The plurality of connector pins 8 have a first end and a second end. The first end is exposed to the outside of the housing 10, and the second end is housed inside the housing 10 and pulled out to the outside. The first end of the connector pin 8 is electrically connected to the connection terminal 2 of the head substrate 3. As a result, the connector 31 is electrically connected to various electrodes of the head substrate 3.

The sealing member 12 has a first sealing member 12a and a second sealing member 12b. The first sealing member 12a is located on the first surface 7f of the substrate 7. The first sealing member 12a seals the connector pin 8 and various electrodes. The second sealing member 12b is located on the second surface 7g of the substrate 7. The second sealing member 12b is arranged so as to seal the contact portion between the connector pin 8 and the substrate 7.

The sealing member 12 is arranged so that the connection terminal 2 and the first end of the connector pin 8 are not exposed to the outside. For example, an epoxy-based thermosetting resin, an ultraviolet curable resin, or visible light is provided. It can be formed of a curable resin. The first sealing member 12a and the second sealing member 12b may be made of the same material. Further, the first sealing member 12a and the second sealing member 12b may be formed of different materials.

The adhesive member 14 is arranged on the heat radiating plate 1 and joins the second surface 7g of the head substrate 3 and the heat radiating plate 1. As the adhesive member 14, a double-sided tape or a resinous adhesive can be exemplified.

The protective layer 25 will be described in detail with reference to FIG.

The protective layer 25 includes a first protective layer 25a and a second protective layer 25b. The first protective layer 25a is located on the substrate 7. More specifically, the first protective layer 25a covers the entire area of the heat generating portion 9. Further, the first protective layer 25a covers a part of the electrode as shown in FIG. More specifically, the first protective layer 25a covers the entire area of the main wiring portion 17a, a part of the sub wiring portion 17b on the first long side 7a side, and the entire area of the lead portion 17c. The layer 25a covers a part of the individual electrode 19 on the heat generating portion 9 side.

Examples of the first protective layer 25a include TiN, TiON, TiCrN, TiAlON and the like. When TiN is used as the first protective layer 25a, for example, it can be set to contain 40 to 60 atomic% of Ti and 40 to 60 atomic% of N. The first protective layer 25a may be, for example, SiN, SiON, SiO ² , SiAlON, SiC, or the like. Hereinafter, the description will be given based on an example in which the first protective layer 25a is formed of TiN.

The first protective layer 25a contains the first crystal particles. In this example, the first crystal particle is TiN. The average crystal grain size of the first crystal particles is, for example, 80 to 240 nm. The standard deviation of the average crystal grain size of the first crystal particles is, for example, 73 to 120 nm.

The thickness of the first protective layer 25a can be set to 2 to 6 μm. By setting the thickness of the first protective layer 25a to 2 μm or more, the adhesion between the heat generating portion 9 and the electrodes is improved. Further, by setting the thickness of the first protective layer 25a to 6 μm or less, the heat of the heat generating portion 9 can be easily transferred to the recording medium P, and the thermal efficiency of the thermal head X1 is improved.

The arithmetic surface roughness Ra of the first protective layer 25a is, for example, 30.0 nm or less. As a result, the adhesion to the second protective layer 25b provided on the first protective layer 25a is improved.

The second protective layer 25b may be formed of the same material as the first protective layer 25a. That is, when the first protective layer 25a is formed of TiN, the second protective layer 25b may also be formed of TiN. Further, the second protective layer 25b may be made of a material different from that of the first protective layer 25a. Hereinafter, the second protective layer 25b will be described with reference to an example when the second protective layer 25b is also formed of TiN.

The second protective layer 25b contains the second crystal particles. In this example, the second crystal particle is TiN. The average crystal grain size of the second crystal particles is, for example, 240 to 720 nm. The standard deviation of the average crystal grain size of the second crystal particles is, for example, 220 to 360 nm.

The thickness of the second protective layer 25b can be set to 2 to 6 μm. By setting the thickness of the second protective layer 25b to 2 μm or more, the wear resistance is improved. Further, by setting the thickness of the second protective layer 25b to 6 μm or less, the heat of the heat generating portion 9 can be easily transferred to the recording medium P, and the thermal efficiency of the thermal head X1 is improved. The second protective layer 25b is the outermost layer and is in contact with the recording medium P.

The arithmetic surface roughness Ra of the second protective layer 25b is, for example, 67.7 nm or less. Thereby, the contact area between the second protective layer 25b and the recording medium P can be reduced, and therefore the frictional force generated between the second protective layer 25b and the recording medium P can be reduced. As a result, the wear resistance of the second protective layer 25b can be improved.

In the thermal head X1, the average crystal grain size of the second crystal particles is larger than the average crystal grain size of the first crystal particles. Therefore, the reliability of the protective layer 25 is improved. The details will be described below.

With the above configuration, the second crystal particles having a relatively large particle size are located in the second protective layer 25b that comes into contact with the recording medium. As a result, the contact area between the grain boundaries and the recording medium P per unit area becomes small, and the frictional force generated in the second protective layer 25b becomes small. Therefore, the second protective layer 25b is less likely to be worn, and the wear resistance of the protective layer 25 can be improved.

Further, in the first protective layer 25a that covers the heat generating portion 9 and a part of the electrode, the first crystal particles having a relatively small particle size are located. As a result, the first crystal particles easily enter into the fine recesses formed on the surfaces of the heat generating portion 9 and the electrode, and the adhesion between the first protective layer 25a and the heat generating portion 9 and the electrode is improved. As a result, the adhesion of the protective layer 25 is improved. From the above, the reliability of the protective layer 25 can be improved.

Further, the average crystal grain size of the second crystal particles may be 240 to 720 nm. As a result, the contact area between the grain boundaries and the recording medium per unit area becomes smaller, and the wear resistance of the second protective layer 25b is improved. Therefore, the reliability of the protective layer 25 is improved.

Further, the average crystal grain size of the first crystal particles may be 80 to 240 nm. As a result, the first crystal particles are more likely to enter into the fine recesses formed on the surfaces of the heat generating portion 9 and the electrode, and the adhesion of the first protective layer 25a is improved. Therefore, the reliability of the protective layer 25 is improved.

Further, the standard deviation of the average crystal grain size of the second crystal particles may be larger than the standard deviation of the average crystal grain size of the first crystal particles. As a result, the reliability of the protective layer 25 is improved. This will be described in detail below.

With the above configuration, second crystal particles of various sizes are located in the second protective layer 25b that comes into contact with the recording medium P. As a result, the second crystal particles having a large particle size support the recording medium P, and the second crystal particles having a small particle size can make the second protective layer 25b dense. That is, the second protective layer 25b is mainly composed of the second crystal particles having a large particle size, and the second crystal particles having a small particle size are located between the particles of the second crystal particles having a large particle size. 2 The protective layer 25b can be made dense. Therefore, the wear resistance of the second protective layer 25b is improved.

When the standard deviation of the average crystal grain size of the first crystal particles is smaller than the standard deviation of the average crystal grain size of the second crystal particles, the first protective layer 25a covering the heat generating portion 9 and a part of the electrode , The first crystal particles having a relatively uniform particle size will be located. As a result, the first crystal particles easily enter into the fine recesses formed on the surfaces of the heat generating portion 9 and the electrode, and the adhesion of the first protective layer 25a is improved. From the above, the reliability of the protective layer 25 can be improved.

The average crystal grain size of the second crystal particles can be confirmed by, for example, the following method. First, the surface of the second protective layer 25b is exposed to a scanning electron microscope (SEM).
Take a picture using a microscope). Subsequently, the second crystal particles are marked from the photographed surface photograph, image analysis is performed, and the particle size data of the second crystal particles is measured. In the present specification, the average crystal grain size means the median diameter (d50). Further, the standard deviation of the average crystal grain size can be calculated based on the grain size data of the crystal particles.

Further, the average crystal grain size of the first crystal particles is obtained by removing the second protective layer 25b by polishing or cutting to expose the first protective layer 25a, and using an SEM to expose the exposed surface of the first protective layer 25a. Take a picture. Hereinafter, the description is omitted because it is the same as the second crystal particle.

Further, the value of the thickness of the second protective layer 25b may be larger than the value of the thickness of the first protective layer 25a. As a result, in the second protective layer 25b that comes into contact with the recording medium P, the large value of the thickness improves the wear resistance of the protective layer 25. Further, since the value of the thickness of the first protective layer 25a is small, the heat of the heat generating portion 9 can be efficiently transferred to the second protective layer 25b, and the thermal efficiency of the thermal head X1 can be improved.

Further, since the average crystal grain size of the second protective layer 25b is larger than that of the first protective layer 25a, the second protective layer 25b has a structure in which heat conduction is easier than that of the first protective layer 25a. That is, the second protective layer 25b has a large average crystal grain size, crystals grow in the thickness direction of the protective layer 25, and heat conduction is easy. Therefore, even if the thickness of the second protective layer 25b is increased, heat can be efficiently transferred to the recording medium P.

The thickness of the first protective layer 25a and the second protective layer 25b is measured from the cut surface by cutting the thermal head X1 in the thickness direction.

Further, the calculated surface roughness value of the second protective layer 25b may be larger than the arithmetic surface roughness value of the first protective layer 25a. As a result, in the second protective layer 25b that comes into contact with the recording medium P, the contact area between the second protective layer 25b and the recording medium P decreases due to the large value of the arithmetic surface roughness. As a result, the recording medium P sticks to the second protective layer 25b, so-called sticking is less likely to occur.

Further, in the first protective layer 25a covering the heat generating portion 9 and a part of the electrode, the contact area between the heat generating portion 9 and the electrode and the first protective layer 25a increases due to the small value of the arithmetic surface roughness. , The adhesion of the protective layer 25 is improved.

The arithmetic surface roughness Ra is measured using an atomic force microscope (AFM: Atomic Force Microscope). Further, a contact type or non-contact type surface roughness meter may be used.

The protective layer 25 can be formed by an arc plasma type ion plating or a hollow cathode type ion plating.

The control of the average crystal grain size of the first crystal particles and the second crystal particles can be controlled by, for example, the following method. For example, when the protective layer 25 is formed by the arc plasma ion plating method, the absolute value of the substrate bias voltage applied at the time of forming the second protective layer 25b should be smaller than that at the time of forming the first protective layer 25a. Just do it. Further, the film forming pressure at the time of forming the second protective layer 25b may be higher than that at the time of forming the first protective layer 25a. Further, the temperature at the time of film formation of the second protective layer 25b may be higher than that at the time of forming the first protective layer 25a.

Next, the thermal printer Z1 having the thermal head X1 will be described with reference to FIG.

The thermal printer Z1 of the present embodiment includes the above-mentioned thermal head X1, a transport mechanism 40, a platen roller 50, a power supply device 60, and a control device 70. The thermal head X1 is attached to the attachment surface 80a of the attachment member 80 arranged in the housing (not shown) of the thermal printer Z1. The thermal head X1 is attached to the attachment member 80 so as to be along the main scanning direction which is a direction orthogonal to the transport direction S.

The transport mechanism 40 has a drive unit (not shown) and transport rollers 43, 45, 47, 49. The transport mechanism 40 transports the recording medium P such as the thermal paper and the image receiving paper on which the ink is transferred in the direction of the arrow S in FIG. 5 on the protective layer 25 located on the plurality of heat generating portions 9 of the thermal head X1. It is for transporting. The drive unit has a function of driving the transfer rollers 43, 45, 47, 49, and for example, a motor can be used. In the transport rollers 43, 45, 47, 49, for example, a columnar shaft body 43a, 45a, 47a, 49a made of a metal such as stainless steel is covered with elastic members 43b, 45b, 47b, 49b made of butadiene rubber or the like. Can be configured. When the recording medium P is an image receiving paper or the like on which ink is transferred, an ink film (not shown) is conveyed between the recording medium P and the heat generating portion 9 of the thermal head X1 together with the recording medium P.

The platen roller 50 has a function of pressing the recording medium P onto the protective layer 25 located on the heat generating portion 9 of the thermal head X1. The platen roller 50 is arranged so as to extend along a direction orthogonal to the transport direction S, 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 9. The platen roller 50 can be configured by, for example, covering a columnar shaft body 50a made of a metal such as stainless steel with an elastic member 50b made of butadiene rubber or the like.

As described above, the power supply device 60 has a function of supplying a current for heating the heat generating portion 9 of the thermal head X1 and a current for operating the drive IC 11. The control device 70 has a function of supplying a control signal for controlling the operation of the drive IC 11 to the drive IC 11 in order to selectively generate heat of the heat generation unit 9 of the thermal head X1 as described above.

The thermal printer Z1 presses the recording medium P onto the heat generating portion 9 of the thermal head X1 by the platen roller 50, and conveys the recording medium P onto the heat generating portion 9 by the conveying mechanism 40, while the power supply device 60 and the control device 70. By selectively generating heat in the heat generating unit 9, 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.

Cut paper may be used as the recording medium P. In the cut paper, the rear end of the cut paper is struck against the second protective layer 25b each time the transport is completed, but in the thermal head X1, the average crystal grain size of the second crystal particles is the first crystal. Since it is larger than the average crystal grain size of the particles, the wear resistance of the second protective layer 25b is improved. Therefore, the reliability of the protective layer 25 is improved, and the thermal printer Z1 with improved reliability can be obtained.

As described above, the thermal head of the present disclosure is not limited to the above embodiment, and various changes can be made as long as the purpose is not deviated. For example, a thin thin film head having a heat generating portion 9 in which the electric resistance layer 15 is formed of a thin film is shown as an example, but the present invention is not limited thereto. After patterning the various electrodes, the thick film head of the heat generating portion 9 may be formed by forming the electric resistance layer 15 with a thick film.

Further, although the flat head in which the heat generating portion 9 is formed on the first surface 7f of the substrate 7 has been described as an example, an end face head in which the heat generating portion 9 is located on the end surface of the substrate 7 may be used.

Further, the heat generating portion 9 may be formed by forming the common electrode 17 and the individual electrode 19 on the heat storage layer 13 and forming the electric resistance layer 15 only in the region between the common electrode 17 and the individual electrode 19. ..

Further, the sealing member 12 may be formed of the same material as the covering member 29 that covers the drive IC 11. In that case, when printing the covering member 29, the covering member 29 and the sealing member 12 may be formed at the same time by printing on the region where the sealing member 12 is formed.

Further, although an example in which the connector 31 is directly connected to the board 7 is shown, a flexible printed circuits (FPC) may be connected to the board 7.

X1 Thermal head Z1 Thermal printer 1 Heat sink 3 Head base 7 Board 9 Heat generation part 11 Drive IC
12 Sealing member 13 Heat storage layer 14 Adhesive member 15 Electrical resistance layer 17 Common electrode 19 Individual electrode 21 First connection electrode 25 Protective layer
25a 1st protective layer 25b 2nd protective layer 26 2nd connection electrode 27 Coating layer 31 Connector

Claims (7)

With the board
The heat generating part located on the substrate and
An electrode located on the substrate and connected to the heat generating portion, and
A first protective layer that covers the heat generating portion and a part of the electrode,
A second protective layer located on the first protective layer is provided.
The first protective layer contains first crystal particles and contains.
The second protective layer contains second crystal particles and contains.
The average crystal grain size of the second crystal particles is larger than the average crystal grain size of the first crystal particles.
A thermal head in which the standard deviation of the average crystal grain size of the second crystal particles is larger than the standard deviation of the average crystal grain size of the first crystal particles . With the board
The heat generating part located on the substrate and
An electrode located on the substrate and connected to the heat generating portion, and
A first protective layer that covers the heat generating portion and a part of the electrode,
A second protective layer located on the first protective layer is provided.
The first protective layer contains first crystal particles and contains.
The second protective layer contains second crystal particles and contains.
The average crystal grain size of the second crystal particles is larger than the average crystal grain size of the first crystal particles.
A thermal head in which the value of the thickness of the second protective layer is larger than the value of the thickness of the first protective layer. The thermal head according to claim 1 or 2 , wherein the average crystal grain size of the second crystal particles is 240 nm to 720 nm. The thermal head according to claim 3 , wherein the average crystal grain size of the first crystal particles is 80 nm to 240 nm. The thermal head according to any one of claims 1 to 4 , wherein the value of the arithmetic surface roughness of the second protective layer is larger than the value of the arithmetic surface roughness of the first protective layer. The thermal head according to any one of claims 1 to 5 .
A transport mechanism that transports the recording medium onto the heat generating portion,
A thermal printer comprising a platen roller for pressing the recording medium. The thermal printer according to claim 6 , wherein the recording medium is cut paper.

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