JP2014000729A - Thermal head, printer and manufacturing method for thermal head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply and inexpensively manufacture a thermal head that has high reliability, accelerates printing speed and reduces electric power consumption.SOLUTION: A manufacturing method for a thermal head comprises; a second penetration hole form step SA1 for forming a first penetration hole penetrating a first support substrate in a thickness direction thereof and forming two or more second penetration holes penetrating a second support substrate in a thickness direction thereof and each having an area smaller than the area of the first penetration hole; a filling step SA2 for filling metallic material into the first penetration hole; a jointing step SA3 for laminating the first support substrate and the second support substrate such that the first penetration hole coincides with the second penetration holes, and jointing them; an electrical insulation coating formation step SA4 for forming an electrical insulation coat on one surface opposite to a joint surface of the first support substrate with the second support substrate; a removal step SA5 for removing the metallic material filled into the first penetration hole from the second penetration holes; and a resistive element formation step SA6 for forming a heat resistive element at a position facing the first penetration hole of the first support substrate on surface of the electrical insulation coat.

Description

  The present invention relates to a thermal head manufacturing method, a thermal head, and a printer.

  2. Description of the Related Art Conventionally, in a thermal head used in a thermal printer, a cavity is formed in a region of a substrate facing a heating resistor, and the cavity is made to function as a heat insulating layer having a low thermal conductivity. It is known to improve the heat generation efficiency by reducing the amount of heat flowing to the power source and to reduce power consumption (see, for example, Patent Document 1).

  In the thermal head described in Patent Document 1, a substrate on which glass is printed and baked in a straight line on one surface of a flat plate-like ceramic base is formed from the other surface of the ceramic base along the center of the straight glass. By processing the groove, the groove penetrates the ceramic substrate and leaves the surface of the glass several tens of μm so that the groove functions as a hollow portion.

JP 2009-18558 A

  However, since the thermal head described in Patent Document 1 has a groove formed by penetrating the ceramic substrate and leaving several tens of μm from the glass surface, the rigidity of the entire substrate is lowered, and the substrate is deformed based on the groove. Cheap. For this reason, there is a problem that reliability as a thermal head is low, such as a glass having a thickness of several tens of μm formed on one surface of a ceramic substrate is broken.

  In addition, the thermal head described in Patent Document 1 has a groove formed by grinding a brittle glass as compared with a ceramic such as alumina, which is a substrate material. There is an inconvenience that sometimes enters. Furthermore, since the groove processing is performed up to the glass layer, there is a problem that the controllability of the thickness of the glass layer that affects the heat generation efficiency is poor.

  The present invention has been made in view of the above-described circumstances, and has a high reliability, a manufacturing method capable of easily and inexpensively manufacturing a thermal head that increases printing speed and reduces power consumption. It is an object of the present invention to provide a thermal head manufactured by the method and a printer including the thermal head.

In order to achieve the above object, the present invention provides the following means.
The present invention provides a first through hole forming step of forming a first through hole penetrating the first support substrate in the plate thickness direction, and an area of the first through hole penetrating the second support substrate in the plate thickness direction. A second through hole forming step of forming one or more second through holes having a small area, a filling step of filling the first through hole with a metal material, and a first support filled with the metal material A bonding step of stacking and bonding the substrate and the second support substrate so that the first through hole and the second through hole coincide with each other; and bonding of the first support substrate to the second support substrate An insulating film forming step of forming an insulating film made of an insulating material on one surface opposite to the surface; a removing step of removing the metal material filled in the first through hole from the second through hole; Opposite the first through hole of the first support substrate on the surface of the insulating coating To provide a manufacturing method for a thermal head and a resistor forming step of forming a heating resistor at a position that.

  According to the present invention, the first support substrate and the second support substrate are joined in a stacked state by matching the first through hole and the second through hole by the joining step, and the first support substrate is formed by the insulating film forming step. By forming the insulating coating on one surface, a laminated substrate in which one opening of the exposed first through hole of the first support substrate is closed by the insulating coating is formed. Then, the first through hole of the first support substrate is filled with the metal material by the filling step, and the metal material is removed from the second through hole of the second support substrate by the removal step, so that the first inside the multilayer substrate is obtained. A cavity is formed in the region of the through hole.

  The hollow portion functions as a hollow heat insulating layer that blocks heat transferred from the insulating coating side to the first support substrate and the second support substrate side. Therefore, by forming the heating resistor on the surface of the insulating coating so as to oppose the first through hole of the first support substrate by the resistor forming step, the heat generated in the heating resistor is generated via the insulating coating. The thermal head capable of suppressing the escape to the side of the first support substrate and the second support substrate by the hollow portion and increasing the amount of available heat is completed.

  In this case, by making the area of the second through hole of the second support substrate smaller than the area of the first through hole of the first support substrate, while securing a passage for removing the metal material of the first through hole, The rigidity of the laminated substrate can be kept high. Thereby, in the communication cavity part structure in which a high heat insulation effect is obtained as compared with the individual cavity part structure formed for each heating resistor, both high heat generation efficiency and high substrate strength can be achieved. As a result, even when receiving a load from the platen roller during printing, highly efficient printing can be performed without damaging the insulating coating.

  Further, by filling the first through hole of the first support substrate with a metal material by the filling step, a flat insulating film is formed on one surface of the first support substrate in the insulating film forming step, and in the resistor forming step. A heating resistor can be accurately formed on the surface of the insulating coating. Furthermore, by filling only the first through hole of the first support substrate with the metal material, it is possible to shorten the time taken to remove the metal material in the removal process. Therefore, it is possible to easily and inexpensively manufacture a thermal head that is highly reliable and that can increase the printing speed and reduce the power consumption.

  In the above invention, the filling step fills the second through-hole with a metal material together with the first through-hole, and the removing step fills the first through-hole with the metal material filled in the second through-hole. It is good also as removing with the said metal material with which the hole was filled.

  By comprising in this way, the metal material with which the 2nd through-hole of the 2nd support substrate was filled supports the metal material with which the 1st through-hole of the 1st support substrate was filled, and an insulating film is formed. The flatness of one surface of the first support substrate can be maintained.

  In the above invention, the second through hole forming step forms the second through hole in the plurality of second support substrates, and the joining step includes the first support substrate and the plurality of second support members. The substrate may be laminated and bonded so that the first through holes and the second through holes coincide with each other.

  By comprising in this way, the 1st through-hole and 2nd through-hole which are filled or removed with a metal material are formed for every 1st support substrate and several 2nd support substrate, The aspect-ratio (( The relationship between the diameter and length of the through hole can be reduced according to the number of substrates. Usually, it is difficult to accurately produce a through-hole having a large aspect ratio, and therefore, a plurality of through-holes formed easily and accurately are provided below the heating resistor as compared with a case where the substrate is configured as a single unit. be able to.

  The present invention includes a through hole forming step for forming one or more through holes penetrating in a plate thickness direction in a plurality of support substrates, and a filling step for filling a metal material into the through holes of at least one of the support substrates; A metal layer forming step of forming a metal layer made of a metal material in a region including an opening of the through hole on one surface of the one support substrate filled with the metal material; and the metal layer is formed The one supporting substrate and the other supporting substrate are laminated and joined so that the through holes coincide with each other, and the one surface of the one supporting substrate joined by the joining step, An insulating film forming step of forming an insulating film made of an insulating material covering the metal layer, a removing step of removing the metal material filled in the metal layer and the through hole from the through hole, and a surface of the insulating film. The metal To provide a manufacturing method for a thermal head and a resistor forming step of forming a heating resistor at a position opposed to.

  According to the present invention, a plurality of support substrates are joined in a laminated state by matching the through holes by the joining step, and a metal layer is formed in a region including the openings of the through holes of the support substrate exposed by the metal layer forming step. At the same time, the metal layer is covered with the insulating film in the insulating film forming step, so that a laminated substrate of the support substrate and the insulating film is formed. Then, the through hole is filled with a metal material by the filling process, and the metal material and the metal layer are removed from the through hole by the removal process, thereby forming a cavity in the region where the metal layer is formed inside the laminated substrate. Is done.

  In this case, the support substrate on which the metal layer is formed by the metal layer forming step is filled with a metal material in the through hole by the filling step, so that one surface of the support substrate is flattened in the metal layer forming step. A flat metal film covering the metal layer can be formed on one surface of the support substrate in the insulating film forming step. Accordingly, the heating resistor can be accurately formed on the surface of the insulating coating in the resistor forming step, and a cavity having a desired shape can be accurately formed by the insulating coating and the support substrate.

In the said invention, it is good also as performing the said removal process after the said resistor formation process.
With this configuration, when the heating resistor is formed on the surface of the insulating film by the resistor forming step, it is possible to suppress a decrease in yield such as breakage of the insulating film.

The present invention provides a thermal head manufactured by any one of the thermal head manufacturing methods described above.
Moreover, this invention provides a printer provided with the said thermal head.

  According to the present invention, there is an effect that it is possible to easily and inexpensively manufacture a thermal head that is highly reliable and that achieves high printing speed and low power consumption.

(A) is the schematic block diagram which looked at the thermal head manufactured by the manufacturing method of the thermal head concerning 1st Embodiment of this invention from the protective film side in the lamination direction, (b) is A- of (a). It is A sectional drawing. It is BB sectional drawing of Fig.1 (a). It is a flowchart explaining the manufacturing method of the thermal head which concerns on 1st Embodiment of this invention. (A) is a longitudinal cross-sectional view of each ceramic substrate at the time of the through-hole formation process which concerns on 1st Embodiment of this invention, (b) is thickness of one surface of the 1st ceramic substrate at the time of a through-hole formation process similarly It is the figure seen from the direction, (c) is the figure which looked at one surface of the 3rd ceramic substrate at the time of a through-hole formation process similarly in the thickness direction. (A) is the longitudinal cross-sectional view of each ceramic substrate at the time of the filling process which concerns on 1st Embodiment of this invention, (b) looked at one surface of the 1st ceramic substrate at the time of the filling process similarly in the thickness direction. (C) is the figure which looked at the surface of the 3rd ceramic substrate at the time of a filling process similarly in the thickness direction. (A) is a longitudinal cross-sectional view of each ceramic substrate at the time of lamination | stacking in the joining process which concerns on 1st Embodiment of this invention, (b) is the thickness of one surface of the 1st ceramic substrate at the time of lamination | stacking in a joining process similarly. It is the figure seen in the direction. (A) is a longitudinal cross-sectional view of each ceramic substrate at the time of firing in the joining step according to the first embodiment of the present invention, and (b) is a thickness of one surface of the first ceramic substrate at the time of firing in the joining step. It is the figure seen in the direction. (A) is a longitudinal cross-sectional view of the multilayer substrate at the time of the insulating film formation process which concerns on 1st Embodiment of this invention, (b) similarly sees one surface of the multilayer substrate at the time of an insulating film formation process in thickness direction. It is a figure. (A) is the longitudinal cross-sectional view of the laminated substrate at the time of the removal process which concerns on 1st Embodiment of this invention, (b) is the figure which looked at the one surface of the laminated substrate at the time of the removal process similarly in the thickness direction. . It is the figure which looked at the laminated substrate at the time of the resistor formation process which concerns on 1st Embodiment of this invention in the lamination direction. It is the figure which looked at the lamination substrate at the time of the electrode formation process concerning a 1st embodiment of the present invention in the lamination direction. It is the figure which looked at the lamination substrate at the time of the protective film formation process concerning a 1st embodiment of the present invention in the lamination direction. (A) is a longitudinal cross-sectional view of each ceramic substrate at the time of the through-hole formation process which concerns on the modification of 1st Embodiment of this invention, (b) is one surface of the 1st ceramic substrate at the same time at the through-hole formation process (C) is the figure which looked at the surface of the 3rd ceramic board | substrate at the time of a through-hole formation process similarly in the thickness direction. (A) is a longitudinal cross-sectional view of each ceramic board | substrate at the time of the filling process which concerns on the modification of 1st Embodiment of this invention, (b) is one surface of the 1st ceramic board | substrate at the time of a filling process similarly to thickness direction (C) is the figure which looked at the surface of the 3rd ceramic substrate at the time of a filling process similarly in the thickness direction. (A) is a longitudinal cross-sectional view of each ceramic substrate at the time of lamination | stacking in the joining process which concerns on the modification of 1st Embodiment of this invention, (b) is one surface of the 1st ceramic substrate at the time of lamination | stacking in a joining process similarly It is the figure which looked at the thickness direction. (A) is a longitudinal cross-sectional view of each ceramic substrate at the time of firing in the joining step according to a modification of the first embodiment of the present invention, and (b) is one surface of the first ceramic substrate at the time of firing in the joining step. It is the figure which looked at the thickness direction. (A) is a longitudinal cross-sectional view of each ceramic substrate at the time of the insulating film formation process which concerns on the modification of 1st Embodiment of this invention, (b) is one surface of the 1st ceramic substrate at the time of an insulating film formation process similarly It is the figure which looked at the thickness direction. (A) is a longitudinal cross-sectional view of each ceramic board | substrate at the time of the removal process which concerns on the modification of 1st Embodiment of this invention, (b) is one surface of the 1st ceramic board | substrate at the time of a removal process similarly in thickness direction FIG. (A) is the schematic block diagram which looked at the thermal head manufactured by the manufacturing method of the thermal head which concerns on 2nd Embodiment of this invention from the protective film side in the lamination direction, (b) is C- of (a). It is C sectional drawing. It is DD sectional drawing of Fig.19 (a). It is a flowchart explaining the manufacturing method of the thermal head which concerns on 2nd Embodiment of this invention. (A) is a longitudinal cross-sectional view of each ceramic substrate at the time of the through-hole formation process which concerns on 2nd Embodiment of this invention, (b) is thickness of one surface of the 1st ceramic substrate at the time of a through-hole formation process similarly It is the figure seen in the direction. (A) is a longitudinal cross-sectional view of each ceramic substrate at the time of the filling step according to the second embodiment of the present invention, and (b) similarly shows one surface of the first ceramic substrate at the time of the filling step in the thickness direction. FIG. (A) is a longitudinal cross-sectional view of each ceramic substrate at the time of lamination | stacking in the metal layer formation process which concerns on 2nd Embodiment of this invention, (b) is one of the 1st ceramic substrates at the time of lamination | stacking in a metal layer formation process similarly. It is the figure which looked at the surface in the thickness direction, (c) is the figure which looked at one surface of the 3rd ceramic substrate at the time of a metal layer formation process similarly in the thickness direction. (A) is a longitudinal cross-sectional view of each ceramic substrate at the time of lamination | stacking in the joining process which concerns on 2nd Embodiment of this invention, (b) is thickness of one surface of the 1st ceramic substrate at the time of lamination | stacking in a joining process similarly. It is the figure seen in the direction. (A) is a longitudinal cross-sectional view of each ceramic substrate at the time of firing in the joining step according to the second embodiment of the present invention, and (b) is a thickness of one surface of the first ceramic substrate at the time of firing in the joining step. It is the figure seen in the direction. (A) is a longitudinal cross-sectional view of the multilayer substrate at the time of the insulating film formation process which concerns on 2nd Embodiment of this invention, (b) similarly sees one surface of the multilayer substrate at the time of an insulating film formation process in thickness direction. It is a figure. (A) is the longitudinal cross-sectional view of the laminated substrate at the time of the removal process which concerns on 2nd Embodiment of this invention, (b) is the figure which looked at the one surface of the laminated substrate at the time of the removal process similarly to the thickness direction. . (A) is a longitudinal cross-sectional view of each ceramic substrate at the time of the through-hole formation process which concerns on the modification of 2nd Embodiment of this invention, (b) is one surface of the 1st ceramic substrate at the same time at the through-hole formation process It is the figure which looked at the thickness direction. (A) is a longitudinal cross-sectional view of each ceramic board | substrate at the time of the filling process which concerns on the modification of 2nd Embodiment of this invention, (b) is the thickness direction of one surface of the 1st ceramic board | substrate at the time of a filling process similarly. FIG. (A) is a longitudinal cross-sectional view of each ceramic substrate at the time of lamination | stacking in the metal layer formation process which concerns on the modification of 2nd Embodiment of this invention, (b) is the 1st ceramic at the time of lamination | stacking in a metal layer formation process similarly. It is the figure which looked at the one surface of the board | substrate in the thickness direction, (c) is the figure which looked at the one surface of the 3rd ceramic substrate at the time of a metal layer formation process similarly. (A) is a longitudinal cross-sectional view of each ceramic substrate at the time of lamination | stacking in the joining process which concerns on the modification of 2nd Embodiment of this invention, (b) is one surface of the 1st ceramic substrate at the time of lamination | stacking in a joining process similarly It is the figure which looked at the thickness direction. (A) is a longitudinal cross-sectional view of each ceramic substrate at the time of firing in the joining step according to the modification of the second embodiment of the present invention, and (b) is one surface of the first ceramic substrate at the time of firing in the joining step. It is the figure which looked at the thickness direction. (A) is a longitudinal cross-sectional view of the laminated substrate at the time of the insulating film formation process which concerns on the modification of 2nd Embodiment of this invention, (b) is thickness of one surface of the laminated substrate at the time of an insulating film formation process similarly It is the figure seen in the direction. (A) is the longitudinal cross-sectional view of the laminated substrate at the time of the removal process which concerns on the modification of 2nd Embodiment of this invention, (b) looked at one surface of the laminated substrate at the time of the removal process similarly to the thickness direction. FIG.

[First Embodiment]
Hereinafter, a thermal head manufacturing method, a thermal head, and a printer according to a first embodiment of the present invention will be described with reference to the drawings.
The thermal head manufacturing method according to the present embodiment can manufacture, for example, a thermal head 10 used in a thermal printer (not shown) as shown in FIGS. 1 (a), 1 (b) and FIG. It is like that.

  In the present manufacturing method, as shown in the flowchart of FIG. 3, a through hole (first through hole) 11A is formed in a first ceramic substrate (first support substrate) 12A, and a second ceramic (second support substrate) 12B. A through hole forming step (first through hole forming step), forming a through hole (second through hole) 11B, and forming a through hole (second through hole) 11C in the third ceramic substrate (second support substrate) 12C. Second through-hole forming step) SA1, a filling step SA2 for filling the through-hole 11A of the first ceramic substrate 12A with the metal paste (metal material) 13, the first ceramic substrate 12A, the second ceramic substrate 12B, and the third ceramic A bonding step SA3 for laminating and bonding the substrates 12C, an insulating film forming step SA4 for forming an insulating film 14 made of an insulating material on one surface of the first ceramic substrate 12A, and a through hole A removal step SA5 for removing the metal paste 13 filled in 1A from the through hole 11B of the second ceramic substrate 12B and the through hole 11C of the third ceramic substrate 12C, and a resistance for forming the heating resistor 15 on the surface of the insulating coating 14 And body forming step SA6.

Further, in the present manufacturing method, an electrode forming process SA7 for connecting the electrode portions 17A and 17B to the heating resistor 15 formed on the surface of the insulating coating 14 and further a protective film formation for forming the protective film 19 on the insulating coating 14 are performed. Step SA8 is included.
Hereinafter, each step will be specifically described.

  In the through-hole forming step SA1, as shown in FIGS. 4A, 4B, and 4C, one through-hole 11A is formed in a rectangular parallelepiped green sheet (referred to as the first ceramic substrate 12A) before firing. It comes to form. In addition, a plurality of (in the present embodiment, two) green sheets (referred to as the second ceramic substrate 12B and the third ceramic substrate 12C) having a rectangular parallelepiped shape before firing each have an area smaller than the area of the through hole 11A. A plurality of (four in the present embodiment) through-holes 11B and 11C are formed.

  By using a green sheet in a soft state before sintering as the material of these ceramic substrates 12A, 12B, and 12C, the processing of the through holes 11A, 11B, and 11C can be facilitated. Further, the through holes 11A, 11B, and 11C can be formed by punching with a mold or cutting with a drill.

As the green sheet, for example, alumina ceramic or low temperature co-fired ceramic (LTCC) mainly composed of SiO ₂ is used. In the present embodiment, an alumina ceramic is exemplified as a green sheet. By using an alumina ceramic having a large Young's modulus, the strength of the entire ceramic substrate 12A, 12B, 12C is increased.

  As shown in FIG. 4B, the through-hole 11A of the first ceramic substrate 12A has a rectangular cross-sectional shape orthogonal to the depth direction, and extends along the longitudinal direction of the first ceramic substrate 12A. It is supposed to be formed. The four through holes 11B of the second ceramic substrate 12B and the four through holes 11C of the third ceramic substrate 12C have a circular cross-sectional shape orthogonal to the depth direction, as shown in FIG. The ceramic substrates 12B and 12C are formed at intervals along the longitudinal direction.

  In the filling step SA2, as shown in FIGS. 5A, 5B, and 5C, the metal paste 13 is filled into the through holes 11A of the first ceramic substrate 12A by screen printing. As the metal paste 13, for example, molybdenum (Mo), which is a refractory metal material that can withstand firing in a later step, can be used.

  In the joining step SA3, as shown in FIGS. 6A and 6B, the first ceramic substrate 12A, the second ceramic substrate 12B, and the third ceramic substrate 12C are arranged in the thickness direction in this order, and these are arranged in the through holes 11A, The through holes 11B and the through holes 11C are stacked so as to coincide with each other in the thickness direction. At this time, all the through holes 11B and 11C of the ceramic substrates 12B and 12C are placed in a region facing the through hole 11A of the first ceramic substrate 12A in the plate thickness direction.

  Further, in the bonding step SA3, as shown in FIGS. 7A and 7B, the laminated ceramic substrates 12A, 12B, and 12C are baked and hardened in a furnace capable of raising the temperature to about 1000 to 2000 ° C. ing. Ceramics after sintering the green sheet have a larger Young's modulus (high rigidity) than silicon, glass, quartz, etc., preventing substrate damage during the process, improving productivity, and also as a thermal head High strength can be obtained.

In the insulating film forming step SA4, as shown in FIGS. 8A and 8B, an insulating film (undercoat layer) 14 having a flat surface shape is formed on one surface of the first ceramic substrate 12A by screen printing. And fired. Thereby, the laminated substrate 20 in which the third ceramic substrate 12C, the second ceramic substrate 12B, the first ceramic substrate 12A, and the insulating coating 14 are sequentially joined in the thickness direction in the plate thickness direction is formed. As a material of the insulating coating 14, for example, a glass paste containing SiO ₂ as a main component can be used.

  In the removing step SA5, as shown in FIGS. 9A and 9B, the metal paste 13 filled in the through holes 11A of the first ceramic substrate 12A is applied to the back surface of the third ceramic substrate 12C by wet etching. It is removed from the side through the through holes 11B and 11C. Thereby, the cavity 23 as a heat insulation layer is formed in the laminated substrate 20 by the through holes 11A, 11B, and 11C.

As a dissolution liquid used for wet etching of the metal paste 13, in the case of using Mo as the material of the metal paste 13, nitric acid (HNO ₃₎ or a solution, and it is possible to use a mixed solution containing nitric acid (HNO ₃₎ . At that time, it is necessary to select an etching solution that dissolves the metal paste 13 without dissolving the insulating coating 14 containing SiO ₂ as a main component.

  In the resistor forming step SA6, as shown in FIG. 10, a plurality of heating resistors 15 are formed on the surface of the insulating coating 14 in a region facing the through hole 11A of the first ceramic substrate 12A in the plate thickness direction. It is like that. Specifically, in the resistor forming step SA6, a thin film of a heat generating resistor material is formed on the insulating coating 14 by using a thin film forming method such as sputtering, CVD (chemical vapor deposition), and vapor deposition, and then off. The heating resistor 15 having a desired shape is formed by forming a thin film of the heating resistor material using a method or an etching method. As the heating resistor material, for example, Ta-based or Ta silicide-based materials are used.

  As shown in FIG. 11, in the electrode forming step SA7, as in the resistor forming step SA6, a wiring material is formed on the insulating film 14 by sputtering, vapor deposition or the like, and this is performed using a lift-off method or an etching method. The electrode portions 17A and 17B having a desired shape are formed by forming a film or baking the wiring material after screen printing.

  The electrode portions 17A and 17B include a plurality of individual electrodes 17A individually connected to one end in the longitudinal direction of the heating resistor 15 and a common electrode 17B commonly connected to the other longitudinal end of all the heating resistors 15. It is configured by. As the wiring material, for example, Al, Al—Si, Au, Ag, Cu, Pt, or the like is used.

  These electrode portions 17A and 17B can supply electric power from an external power source (not shown) to the heating resistor 15 to cause the heating resistor 15 to generate heat. A region between the individual electrode 17A and the common electrode 17B in the heating resistor 15, that is, a region located almost directly above the through hole 11A of the first ceramic substrate 12A in the heating resistor 15 is an effective heating region.

In the protective film forming step SA8, as shown in FIG. 12, a protective film material is formed on the insulating film 14 by sputtering, ion plating, CVD, or the like to form the protective film 19. . As the protective film material, for example, SiO ₂ , Ta ₂ O ₅ , SiAlON, Si ₃ N ₄ , diamond-like carbon, or the like is used.

  Through the above steps, the heating substrate 15, the electrode portions 17 </ b> A, 17 </ b> B, and the protective film 19 are provided on one surface of the laminated substrate 20 in which the ceramic substrates 12 </ b> A, 12 </ b> B, 12 </ b> C and the insulating coating 14 are joined in a laminated state. The thermal head 10 in which the cavity 23 is formed in the region facing the heating resistor 15 by the ceramic substrates 12A, 12B, 12C and the insulating coating 14 is completed.

  In the thermal head 10 manufactured as described above, when a voltage is selectively applied to the individual electrode 17A, the heating resistor 15 to which the selected individual electrode 17A and the common electrode 17B opposed thereto are connected. A current flows through and generates heat. The heat generated in the heating resistor 15 is transmitted to the protective film 19 side and used for printing or the like, while part of the heat is transmitted from the insulating coating 14 to the ceramic substrates 12A, 12B, and 12C.

  Here, the insulating coating 14 functions as a heat storage layer that stores heat generated in the heating resistor 15. On the other hand, the cavity 23 functions as a hollow heat insulating layer that blocks heat transmitted from the insulating coating 14 side to the ceramic substrates 12A, 12B, and 12C side.

  By forming the heating resistor 15 so as to face the through hole 11A of the first ceramic substrate 12A on the surface of the insulating coating 14 by the resistor forming step SA6, the heat generated in the heating resistor 15 is generated by the insulating coating 14. The cavity 23 can effectively suppress the escape to the ceramic substrates 12A, 12B, and 12C through the heat sink, and the heat stored in the ceramic substrates 12A, 12B, and 12C. Therefore, the thermal head 10 that can increase the amount of heat that can be used and improve the utilization efficiency is formed.

  In this case, by making the areas of the through holes 11B and 11C of the second ceramic substrate 12B and the third ceramic substrate 12C smaller than the area of the through holes 11A of the first ceramic substrate 12A, the through holes 11B and 11C are used to form the through holes. The rigidity of the laminated substrate 20 can be kept high while securing a passage for removing the 11A metal paste 13.

  Thereby, in the communication cavity part structure in which a high heat insulating effect is obtained as compared with the individual cavity part structure formed for each heating resistor 15, both high heat generation efficiency and high substrate strength can be achieved. Furthermore, by making the insulating coating 14 have a flat structure, a platen roller (not shown) can be evenly loaded during printing. As a result, even when a load is applied to the platen roller, highly efficient printing is possible without damaging the insulating coating 14. Also, paper jams such as sticking can be prevented.

  Further, by filling the through hole 11A of the first ceramic substrate 12A with the metal paste 13 in the filling step SA2, a flat insulating coating 14 is formed on one surface of the first ceramic substrate 12A in the insulating coating forming step SA4. In the resistor forming step SA6, the heating resistor 15 can be accurately formed on the surface of the insulating coating. Furthermore, by filling only the through-hole 11A of the first ceramic substrate 12A with the metal paste 13, the time taken to remove the metal paste 13 by the removal step SA5 can be shortened.

  Therefore, according to the method for manufacturing a thermal head according to the present embodiment, the thermal head 10 that is highly reliable and that can increase the printing speed and reduce the power consumption can be manufactured easily and inexpensively. Further, by forming the laminated substrate 20 in which the metal paste 13 as a sacrificial layer is embedded using a green sheet, the thermal head 10 of a hollow heat insulating substrate with high mechanical strength can be manufactured accurately and easily.

  In addition, for example, when an etching window for injecting a solution for dissolving the metal paste 13 is formed on the substrate surface, a load of the platen roller is received during printing, or a foreign object hits the etching window. While the thin glass layer of the insulating coating 14 is easily damaged, according to the method for manufacturing the thermal head according to the present embodiment, the etching window (that is, the through holes 11B and 11C) is formed on the back surface of the laminated substrate 20. Thus, the thermal head 10 capable of printing with high efficiency can be manufactured without damaging the thin glass layer of the insulating coating 14.

Further, the formation of the cavity using the metal paste 13 as the sacrificial layer is excellent in thickness controllability of the insulating coating 14 because it is not necessary to etch the insulating coating 14. A structure using a green sheet as the insulating coating 14 is also conceivable. In this case, considering both heat generation efficiency and strength, the thickness of the insulating coating 14 is required to be several μm to several tens of μm. However, as a practical problem, it is difficult to obtain a thin green sheet having a thickness of several μm to several tens of μm. On the other hand, in this embodiment, the thickness can be freely controlled by using a glass pace mainly composed of SiO ₂ as the material of the insulating coating 14.

Further, in forming the hollow portion 23, it is not necessary to apply a large load to the insulating coating 14, and it is possible to prevent the glass layer from cracking and the glass layer from cracking.
Furthermore, the laminated substrate 20 in which the metal paste 13 as the sacrificial layer is embedded is divided into ceramic substrates 12A, 12B, and 12C, so that each of the laminated substrates 20 having the same strength can be realized as a single layer substrate. The aspect ratio of the through holes 11A, 11B, and 11C formed in the ceramic substrates 12A, 12B, and 12C can be reduced. Thereby, the removal path | route of the metal paste 13 and the cavity part 23 can be formed easily.

This embodiment can be modified as follows.
For example, in this embodiment, in the filling step SA2, only the through hole 11A of the first ceramic substrate 12A is filled with the metal paste 13, but the second through hole 11B and the third ceramic of the second ceramic substrate 12B are used. The metal paste 13 may be filled into the third through hole 11C of the substrate 12C.

  In this case, as shown in FIGS. 13A, 13B, and 13C, after the through holes 11A, 11B, and 11C are formed in the ceramic substrates 12A, 12B, and 12C, respectively, through the through hole forming step SA1, FIG. As shown in (a), (b), and (c), the metal paste 13 may be filled into the through holes 11A, 11B, and 11C of the ceramic substrates 12A, 12B, and 12C by the filling step SA2.

  Next, as shown in FIGS. 15A and 15B, the ceramic substrates 12A, 12B, and 12C are laminated in the thickness direction so that the through holes 11A, 11B, and 11C coincide with each other in the joining step SA3. As shown in FIGS. 16A and 16B, these may be fired and bonded.

  Next, as shown in FIGS. 17A and 17B, an insulating coating 14 is formed on one surface of the first ceramic substrate 12A by the insulating coating forming process SA4, and then shown in FIGS. 18A and 18B. As shown, the removal process SA5 removes the metal paste 13 filled in the through holes 11B and 11C of the ceramic substrates 12B and 12C from the through holes 11B and 11C together with the metal paste 13 filled in the through holes 11A. do it.

  By doing so, the metal paste 13 filled in the through holes 11A of the first ceramic substrate 12A is supported by the metal paste 13 filled in the through holes 11B, 11C of the ceramic substrates 12B, 12C, and the insulating coating 14 It is possible to maintain the flatness of one surface of the first ceramic substrate 12A on which is formed.

  For example, when only the through hole 11A of the first ceramic substrate 12A is filled with the metal paste 13 as in the present embodiment, the metal paste 13 may loosen depending on the heating temperature for firing in the joining step SA3. In that case, since the metal paste 13 as the sacrificial layer filled in the through hole 11A moves to the through hole 11B of the second ceramic substrate 12B, the metal paste 13 in the through hole 11A is deformed and the surface of the insulating coating 14 is deformed. Flatness may be reduced. Therefore, it is necessary to control the heating temperature to prevent deformation of the metal paste 13 in the through hole 11A.

  By filling the metal paste 13 in the through holes 11B and 11C of the ceramic substrates 12B and 12C as in this modification, the metal paste 13 in the through hole 11A of the first ceramic substrate 12A is deformed during firing in the joining step SA3. In the insulating film forming step SA4, a flatter insulating film 14 can be formed.

  In the present embodiment, the removal step SA5 is performed before the resistor formation step SA6. However, the removal step SA5 may be performed after the resistor formation step SA6. By doing in this way, in the resistor formation process SA6, since the thin glass layer of the insulating coating 14 is supported by the metal paste 13 of the through hole 11A, the insulating coating 14 is prevented from being damaged and the yield reduction is suppressed. be able to.

  In this case, when removing the metal paste 13 by etching in the removal step SA5, it is necessary to protect the surface of the multilayer substrate 20 or select a solution that does not damage the material constituting the multilayer substrate 20. For example, when the electrode portions 17A and 17B are made of Al, the material of the metal paste 13 as the sacrificial layer is Cu, Mo, or Ni, and fuming nitric acid is selected as the etching solution, the fuming nitric acid is used to form Mo (Cu, Ni During the etching of the metal paste 13 made of), damage to the electrode portions 17A and 17B can be reduced, and the protection of the heating resistor 15 is not required, so that the manufacturing process can be simplified.

[Second Embodiment]
Next, a method for manufacturing a thermal head according to the second embodiment of the present invention will be described.
The thermal head manufacturing method according to the present embodiment includes a metal layer forming step of forming a metal layer made of a metal material on one surface of the first ceramic substrate 12A, and the removing step together with the metal paste 13 is a metal layer forming step. This is different from the first embodiment in that the metal layer formed by the step is also removed.
In the following, portions that share the same configuration as the thermal head manufacturing method according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIGS. 19A, 19B, and 20, the thermal head manufacturing method according to the present embodiment can manufacture a thermal head 110 having a cavity 123 inside the insulating coating. It has become.

  In the thermal head manufacturing method according to the present embodiment, as shown in the flowchart of FIG. 21, a plurality of (three in the present embodiment) ceramic substrates 12A, 12B, and 12C each penetrates in the plate thickness direction. Through-hole forming step SB1 for forming 111A, 11B, 11C, filling step SB2 for filling through-hole 111A of first ceramic substrate 12A with metal paste 13, and opening of through-hole 111A on one surface of first ceramic substrate 12A A metal layer forming step SB3 for forming a metal layer 121 made of a metal material in a region including the portion, a bonding step SB4 for stacking and bonding the ceramic substrates 12A, 12B, and 12C, and one surface of the first ceramic substrate 12A Insulating film forming step SB5 for forming insulating film 14 covering metal layer 121, metal layer 121 and through hole A removal step SB6 for removing the metal paste 13 filled in 11A from the through holes 111A, 11B, and 11C, a resistor formation step SB7 for forming the heating resistor 15 on the surface of the insulating film 14, and an electrode formation step SA7. And a protective film forming step SA8.

  In the through hole forming step SB1, as shown in FIGS. 22A and 22B, a green sheet (first ceramic substrate 12A) having a rectangular parallelepiped shape before firing is used instead of the through hole 11A of the first embodiment. ), Four through holes 111A are formed. In addition, four through holes 11B are formed in a rectangular parallelepiped green sheet (referred to as a second ceramic substrate 12B) before firing, and similarly, four through holes are formed in a green sheet (referred to as a third ceramic substrate 12C). 11C is formed.

  The through-holes 111A of the first ceramic substrate 12A, the through-holes 11B of the second ceramic substrate 12B, and the through-holes 11C of the third ceramic substrate 12C have circular shapes whose cross-sectional shapes orthogonal to the depth direction are the same. The ceramic substrates 12A, 12B, and 12C are formed at the same interval along the longitudinal direction.

  In the filling step SB2, as shown in FIGS. 23A and 23B, the metal paste 13 is filled into the through holes 111A of the first ceramic substrate 12A by screen printing.

  In the metal layer forming step SB3, as shown in FIGS. 24 (a), (b), and (c), screen printing is performed on a region including the openings of all the through holes 111A on one surface of the first ceramic substrate 12A. Thus, the metal layer 121 made of a metal material is patterned. Since the metal layer 121 forms a region that will later become the cavity 123, it is desirable that the metal layer 121 be formed to have a thickness that can secure a space as a heat insulating layer. As the metal material of the metal layer 121, the same material as the metal paste 13 filling the through hole 111A can be used.

  In the bonding step SB4, as shown in FIGS. 25A and 25B, the ceramic substrates 12A, 12B, and 12C are sequentially arranged in the thickness direction, and the through holes 111A, 11B, and 11C are aligned in the thickness direction. As shown in FIGS. 26A and 26B, the laminated ceramic substrates 12A, 12B, and 12C are baked and hardened in a furnace capable of raising the temperature to about 1000 to 2000 ° C. .

  In the insulating film forming step SB5, as shown in FIGS. 27A and 27B, an insulating film having a flat surface shape covering the metal layer 121 is formed on one surface of the first ceramic substrate 12A by screen printing. A coating layer 14 is formed and fired. Thereby, the laminated substrate 20 in which the ceramic substrates 12C, 12B, 12A and the insulating coating 14 are joined in the laminated state in order in the plate thickness direction is formed.

  In the removal step SB6, as shown in FIGS. 28A and 28B, the metal layer 121 and the metal paste 13 filled in the through hole 111A are removed from the back surface side of the third ceramic substrate 12C by wet etching. Removal is performed through the through holes 111A, 11B, and 11C. Thus, a cavity 123 as a heat insulating layer is formed in the laminated substrate 20 by the region where the metal layer 121 covered with the insulating coating 14 is formed and the through holes 111A, 11B, and 11C.

In the resistor forming step SB7, the heating resistor 15 is formed on the surface of the insulating coating 14 at a position facing the metal layer 121 in the plate thickness direction.
Since the electrode forming step SA7 and the protective film forming step SA8 are the same as those in the first embodiment, description thereof is omitted.

  Through the above steps, the heating substrate 15, the electrode portions 17 </ b> A, 17 </ b> B, and the protective film 19 are provided on one surface of the laminated substrate 20 in which the ceramic substrates 12 </ b> A, 12 </ b> B, 12 </ b> C and the insulating coating 14 are joined in a laminated state. The thermal head 110 in which the cavity 123 is formed in a region facing the heating resistor 15 by the ceramic substrates 12A, 12B, 12C and the insulating coating 14 is completed.

  In this case, by filling the through-hole 111A with the metal paste 13 in the filling step SB2 with respect to the first ceramic substrate 12A on which the metal layer 121 is formed in the metal layer forming step SB3, the metal layer forming step SB3. The flat metal layer 121 is formed on one surface of the first ceramic substrate 12A, and the flat insulating film 14 covering the metal layer 121 is formed on the one surface of the first ceramic substrate 12A in the insulating film forming step SB5. it can.

  Thereby, in the resistor forming step SB7, the heating resistor 15 is accurately formed on the surface of the insulating coating 14, and the cavity 123 having a desired shape is accurately formed by the insulating coating 14 and the ceramic substrates 12A, 12B, 12C. be able to.

  Therefore, according to the method for manufacturing a thermal head according to the present embodiment, the thermal head 110 that is highly reliable and that can increase the printing speed and reduce the power consumption can be manufactured easily and inexpensively. Further, by forming the metal layer 121 as a sacrificial layer for forming the cavity 123 on the one surface of the first ceramic substrate 12A, the bonding region between the ceramic substrates 12A, 12B, and 12C is increased, and these are accurately obtained. It can be reliably joined.

This embodiment can be modified as follows.
For example, in this embodiment, in the filling step SB2, only the through hole 111A of the first ceramic substrate 12A is filled with the metal paste 13, but instead, the second through hole of the second ceramic substrate 12B is used. 11B and the third through hole 11C of the third ceramic substrate 12C may be filled with the metal paste 13.

  In this case, as shown in FIGS. 29A and 29B, after the through holes 111A, 11B, and 11C are formed in the ceramic substrates 12A, 12B, and 12C by the through hole forming step SB1, respectively, As shown in (b), the metal paste 13 may be filled into the through holes 111A, 11B, and 11C of the ceramic substrates 12A, 12B, and 12C by the filling step SB2.

  Next, as shown in FIGS. 31A, 31B, and 31C, in the metal layer forming step SB3, on one surface of the first ceramic substrate 12A, the region including the openings of all the through holes 111A is formed. The metal layer 121 is patterned by screen printing, and as shown in FIGS. 32A and 32B, the ceramic substrates 12A, 12B, and 12C are aligned with the through holes 111A, 11B, and 11C by the bonding step SB4. After laminating in the thickness direction, these may be baked and joined as shown in FIGS.

  Next, as shown in FIGS. 34 (a) and 34 (b), after the insulating coating 14 is formed on the one surface of the first ceramic substrate 12A so as to cover the metal layer 121 by the insulating coating forming step SB5, FIG. As shown in a) and (b), the metal paste 13 filled in the through holes 11B and 11C of the ceramic substrates 12B and 12C is replaced with the metal paste 13 filled in the metal layer 121 and the through holes 111A by the removing step SB6. At the same time, it may be removed from the through holes 11B and 11C.

  Thus, the metal paste 13 filled in the through hole 111A of the first ceramic substrate 12A is supported by the metal paste 13 filled in the through holes 11B and 11C of the ceramic substrates 12B and 12C, and the joining step SB4. In this case, the metal paste 13 as the sacrificial layer of the through-hole 11A is not prevented from being deformed during firing. Thereby, the flatness of one surface of the first ceramic substrate 12A on which the insulating coating 14 is formed can be maintained, and a flatter insulating coating 14 can be formed.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included. For example, the present invention is not limited to those applied to the above-described embodiments and modifications, and may be applied to embodiments that appropriately combine the embodiments and modifications, and is not particularly limited.

  In each of the above embodiments, the multilayer substrate 20 in which the metal paste 13 is embedded is formed by the three ceramic substrates 12A, 12B, and 12C. However, the multilayer substrate 20 in which the metal paste 13 is embedded is three or more ceramic substrates. It is good also as comprising by. By doing in this way, the aspect-ratio of the through-hole formed in each ceramic substrate can be made further smaller, and the improvement of the further processing precision and simplification of a manufacturing process can be anticipated.

  In each of the above-described embodiments and modifications thereof, alumina ceramic has been described as an example of the green sheets of the ceramic substrates 12A, 12B, and 12C. However, LTCC may be used instead. . A substrate made of LTCC is smaller than the Young's modulus of alumina ceramic, but has a low thermal conductivity, and high heat generation efficiency can be obtained due to the heat storage effect of the substrate.

Further, when LTCC is used as the green sheet, Cu can be used as the metal paste 13 or the firing temperature of the joining steps SA3 and SB4 can be lowered to about 900 ° C. Furthermore, Cu, Fe, and Ni, which are materials of the low melting point metal paste 13, can be used. In that case, in the removal steps SA5 and SB6, ferric chloride (FeCl ₃ ) solution, sulfuric acid (H ₂ SO ₄ ) Etching can be performed using a solution, or a mixed solution including a ferric chloride (FeCl ₃ ) solution and a sulfuric acid (H ₂ SO ₄ ) solution.

  In the first embodiment, four through holes 11B and 11C are illustrated and described as the second through holes, and there may be one or more second through holes. In the second embodiment, four through holes 111A, 11B, and 11C are exemplified as the through holes. However, the number of through holes may be one or two or more.

Further, the thermal heads 10 and 110 manufactured by the thermal head manufacturing method according to each of the embodiments described above and the modifications thereof are used in a printer, thereby improving heat generation efficiency and saving electric power. Printing can be done over time. Examples of printers include thermal transfer printers that use sublimation transfer ribbons or melt transfer ribbons, rewritable thermal printers that allow color development and evidence of print media, and heat-sensitive active adhesive label printers that exhibit adhesiveness when heated. Applicable.
The thermal heads 10 and 110 can also be applied to uses such as thermal or valve-type ink jet heads that eject ink by heat.

10,110 Thermal head 11A, 111A Through hole (first through hole, through hole)
11B Through hole (second through hole, through hole)
11C Through hole (second through hole, through hole)
12A First ceramic substrate (first support substrate, support substrate)
12B Second ceramic substrate (second support substrate, support substrate)
12C Third ceramic substrate (second support substrate, support substrate)
13 Metal paste (metal material)
14 Insulating coating 15 Heating resistor 121 Metal layer SA1 Through-hole forming step (first through-hole forming step, second through-hole forming step)
SA2, SB2 filling process SA3, SB4 joining process SA4, SB5 insulating film forming process SA5, SB6 removing process SA6, SB7 resistor forming process SB1 through-hole forming process SB3 metal layer forming process

Claims (7)

A first through hole forming step of forming a first through hole penetrating in the thickness direction in the first support substrate;
A second through hole forming step of forming one or two or more second through holes penetrating in the thickness direction of the second support substrate and having an area smaller than the area of the first through holes;
A filling step of filling the first through hole with a metal material;
A bonding step of laminating and bonding the first support substrate filled with the metal material and the second support substrate so that the first through hole and the second through hole coincide;
An insulating film forming step of forming an insulating film made of an insulating material on one surface of the first support substrate opposite to the bonding surface with the second support substrate;
Removing the metal material filled in the first through hole from the second through hole;
And a resistor forming step of forming a heating resistor at a position facing the first through hole of the first support substrate on the surface of the insulating coating. The filling step fills the second through hole with a metal material together with the first through hole,
The method of manufacturing a thermal head according to claim 1, wherein the removing step removes the metal material filled in the second through hole together with the metal material filled in the first through hole. The second through hole forming step forms the second through hole in a plurality of the second support substrates,
The said joining process laminates | stacks and joins the said 1st support substrate and these 2nd support substrate so that the said 1st through-hole and each said 2nd through-hole may correspond. 2. A method for producing a thermal head according to 2. A through hole forming step of forming one or two or more through holes penetrating the plurality of support substrates in the thickness direction;
A filling step of filling the through hole of at least one of the support substrates with a metal material;
A metal layer forming step of forming a metal layer made of a metal material in a region including an opening of the through hole on one surface of the one support substrate filled with the metal material;
A joining step of laminating and joining the one support substrate on which the metal layer is formed and the other support substrate so that the through holes coincide with each other;
An insulating film forming step of forming an insulating film made of an insulating material covering the metal layer on the one surface of the one supporting substrate bonded by the bonding step;
Removing the metal material filled in the metal layer and the through hole from the through hole;
And a resistor forming step of forming a heating resistor at a position facing the metal layer on the surface of the insulating coating.   The method for manufacturing a thermal head according to claim 1, wherein the removing step is performed after the resistor forming step.   A thermal head manufactured by the method for manufacturing a thermal head according to claim 1.   A printer comprising the thermal head according to claim 6.

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