JP6923358B2 - Manufacturing method of thermal print head and thermal print head - Google Patents

Description

The present invention relates to a thermal print head and a method for manufacturing a thermal print head.

Patent Document 1 discloses an example of a conventional thermal print head. The thermal printhead disclosed in the document includes a substrate, a glaze layer, an electrode layer, a resistor layer and a protective layer. The substrate is a plate-shaped member made of an insulating material. The glaze layer is formed on the surface of the substrate and is made of, for example, glass. The electrode layer is formed on the glaze layer, and constitutes a current path for selectively passing a current through the resistor layer. The electrode layer has a common electrode and a plurality of individual electrodes. The common electrode and the individual electrode are electrically opposite electrodes. The resistor layer covers the electrode layer so as to traverse the main scanning direction. The portion of the resistor layer sandwiched between the common electrode and the individual electrode in the main scanning direction becomes the heat generating portion. The protective layer is for protecting the electrode layer, and is made of, for example, glass.

The resistor layer formed by printing a thick film of the resistor paste and then firing it has a cross-sectional shape in which the center in the sub-scanning direction bulges upward and both ends in the sub-scanning direction are thin. When the resistor layer is energized, the current tends to concentrate in the center of the resistor layer in the sub-scanning direction. For this reason, partial heat generation in the center of the resistor layer in the sub-scanning direction becomes remarkable.

Japanese Unexamined Patent Publication No. 2017-13334

The present invention has been devised under the above circumstances, and an object of the present invention is to provide a thermal print head and a method for manufacturing a thermal print head capable of generating heat more uniformly in the resistor layer. And.

The thermal printhead provided by the first aspect of the present invention includes a support including a substrate, an electrode layer, and a plurality of heat generating portions arranged in the main scanning direction, and covers at least a part of the electrode layer. A thermal printhead including a resistor layer, wherein the resistor layer has a strip shape extending in the main scanning direction, and has a pair of side surfaces of the resistor standing upright on both sides in the sub-scanning direction with respect to the direction in which the substrate spreads. Have.

In a preferred embodiment of the present invention, the electrode layer has a plurality of common electrode strips each extending in the sub-scanning direction and spaced apart from each other in the main scanning direction, and each extending in the sub-scanning direction. It has a plurality of individual electrode strips separately arranged between the common electrode strips adjacent to each other, and the resistor layer comprises the plurality of common electrode strips and the plurality of individual electrode strips. Is covered so as to cross in the main scanning direction.

In a preferred embodiment of the invention, the resistor layer has a top surface located between the pair of resistor sides in the sub-scanning direction.

In a preferred embodiment of the present invention, the top surface has a curved surface shape that bulges toward a side away from the substrate.

In a preferred embodiment of the present invention, the top surface has a recess recessed on the substrate side.

In a preferred embodiment of the present invention, the top surface is a flat surface.

In a preferred embodiment of the present invention, the resistor layer is a pair of resistors having a shape that is connected to the substrate side with respect to the side surfaces of the pair of resistors and is located outward in the sub-scanning direction as it approaches the substrate. It has an inclined surface.

In a preferred embodiment of the present invention, the dimension of the inclined surface of the resistor in the thickness direction of the substrate is smaller than the dimension of the side surface of the resistor in the thickness direction.

In a preferred embodiment of the present invention, the common electrode strip-shaped portion and the individual electrode strip-shaped portion are adjacent to both sides of at least one of the main scanning directions and are made of the same material as the resistor layer, and the closer they are to the substrate, the more main they are. A covering body having a covering body inclined surface having a shape located outside the scanning direction is further provided.

In a preferred embodiment of the present invention, the covering is connected to the resistor layer in the thickness direction of the substrate.

In a preferred embodiment of the invention, the support further comprises a glaze layer interposed between the substrate, the electrode layer and the resistor layer.

In a preferred embodiment of the present invention, the glaze layer includes a bulging portion located between the resistor layer and the substrate and bulging to a side away from the substrate.

The method for manufacturing a thermal printhead provided by the second aspect of the present invention includes a conductive paste printing step of printing a conductive paste on a support including a substrate, and an electrode layer by firing the conductive paste. The electrode layer forming step of forming the above electrode layer, the resistor paste printing step of printing the resistor paste so as to cover at least a part of the electrode layer, the drying step of drying the resistor paste, and the dried resistor paste. It is characterized by including a removing step of removing both side portions in the sub-scanning direction of the above, and a resistor layer forming step of forming a resistor layer by firing the resistor paste.

In a preferred embodiment of the present invention, shot blasting is used in the removal step.

In a preferred embodiment of the present invention, in the removing step, a mask having a pair of penetrating portions separated in the sub-scanning direction is used to move the pair of penetrating portions in the main scanning direction with respect to the resistor paste. While moving, the projection material is sprayed from the pair of penetrating portions.

In a preferred embodiment of the present invention, a recess forming step of denting a part of the resistor paste by shot blasting is further provided after the drying step and before the resistor layer forming step.

The method for manufacturing a thermal printhead provided by the third aspect of the present invention includes a resistor paste printing step of printing a resistor paste on an intermediate support and a solvent for the resistor paste printed on the intermediate support. Is absorbed by the intermediate support, and the resistor paste printed on the intermediate support is transferred so as to cover at least a part of the electrode layer formed on the support. It is characterized by comprising a resistor layer forming step of forming a resistor layer by firing the obtained resistor paste.

In a preferred embodiment of the present invention, screen printing is used in the resistor paste printing step.

According to the present invention, the resistor layer can generate heat more uniformly.

Other features and advantages of the present invention will become more apparent with the detailed description given below with reference to the accompanying drawings.

It is a top view which shows the thermal print head based on 1st Embodiment of this invention. It is sectional drawing which follows the line II-II of FIG. It is a main part plan view which shows the thermal print head of FIG. It is an enlarged plan view of the main part which shows the thermal print head of FIG. It is an enlarged plan view of the main part which shows the thermal print head of FIG. It is sectional drawing of the main part along the VI-VI line of FIG. FIG. 5 is an enlarged cross-sectional view of a main part along the VI-VI line of FIG. It is sectional drawing of the main part along the line VIII-VIII of FIG. FIG. 5 is an enlarged cross-sectional view of a main part along the line VIII-VIII of FIG. It is sectional drawing of the main part along the X-ray line of FIG. It is sectional drawing of the main part along the line XI-XI of FIG. FIG. 5 is an enlarged cross-sectional view of a main part along the XI-XI line of FIG. It is a main part plan view which shows an example of the manufacturing method of the thermal printhead of FIG. It is sectional drawing of the main part along the XIV-XIV line of FIG. It is a main part plan view which shows an example of the manufacturing method of the thermal printhead of FIG. It is sectional drawing of the main part along the XVI-XVI line of FIG. It is an enlarged sectional view of the main part which shows the thermal print head based on 2nd Embodiment of this invention. It is sectional drawing of the main part which shows an example of the manufacturing method of the thermal printhead of FIG. It is an enlarged sectional view of the main part which shows the thermal print head based on 3rd Embodiment of this invention. It is sectional drawing of the main part which shows an example of the manufacturing method of the thermal printhead of FIG. It is sectional drawing of the main part which shows an example of the manufacturing method of the thermal printhead of FIG. It is sectional drawing of the main part which shows an example of the manufacturing method of the thermal printhead of FIG. It is sectional drawing of the main part which shows an example of the manufacturing method of the thermal printhead of FIG. It is sectional drawing of the main part which shows the thermal print head based on 4th Embodiment of this invention.

Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

1 to 12 show an example of a thermal print head according to the present invention. The thermal print head A1 of the present embodiment includes a support 1, an electrode layer 3, a resistor layer 4, a protective layer 5, a drive IC 71, a sealing resin 72, a connector 73, a wiring board 74, and a heat radiating member 75. The thermal print head A1 is incorporated in a printer that prints on the thermal paper 82 pressed by the platen roller 81 to produce, for example, a barcode sheet or a receipt. For convenience of understanding, the protective layer 5 is omitted in FIGS. 1 and 3 to 5. In these figures, the main scanning direction x, the sub-scanning direction y, and the thickness direction z of the substrate 11 are used as coordinate references.

FIG. 1 is a plan view showing the thermal print head A1. FIG. 2 is a cross-sectional view taken along the line II-II of FIG. FIG. 3 is a plan view of a main part showing the thermal print head A1. FIG. 4 is an enlarged plan view of a main part showing the thermal print head A1. FIG. 5 is an enlarged plan view of a main part showing the thermal print head A1. FIG. 6 is a cross-sectional view of a main part along the VI-VI line of FIG. FIG. 7 is an enlarged cross-sectional view of a main part along the VI-VI line of FIG. FIG. 8 is a cross-sectional view of a main part along the line VIII-VIII of FIG. FIG. 9 is an enlarged cross-sectional view of a main part along the line VIII-VIII of FIG. FIG. 10 is a cross-sectional view of a main part taken along the line XX of FIG. FIG. 11 is a cross-sectional view of a main part along the XI-XI line of FIG. FIG. 12 is an enlarged cross-sectional view of a main part along the XI-XI line of FIG.

The support 1 supports the electrode layer 3, the resistor layer 4, and the protective layer 5. The support 1 is composed of a substrate 11 and a glaze layer 12.

The substrate 11 is made of, for example, _{ceramics such as AlN and Al 2} O _3, and the thickness thereof is, for example, about 0.6 to 1.0 mm. As shown in FIG. 1, the substrate 11 has an elongated rectangular shape extending long in the main scanning direction x. As shown in FIG. 2, for example, the wiring board 74 in which the base material layer made of glass epoxy resin and the wiring layer made of Cu or the like are laminated may be provided adjacent to the support 1. A heat radiating member 75 made of a metal such as Al is provided on the lower surface of the substrate 11. In the configuration having the wiring board 74, for example, the board 11 and the wiring board 74 are arranged adjacent to each other on the heat radiating member 75, and the wiring of the electrode layer 3 on the board 11 and the wiring board 74 (or an IC connected to this wiring). ) Is connected by, for example, wire bonding. Further, the connector 73 shown in FIG. 1 may be provided on the wiring board 74.

The glaze layer 12 is formed on the substrate 11 and is made of a glass material such as amorphous glass. The softening point of this glass material is, for example, 800 to 850 ° C. The glaze layer 12 is formed by printing a thick film of glass paste and then firing the glass paste. In the present embodiment, the entire upper surface of the substrate 11 in the drawing is covered with the glaze layer 12. Further, in the present embodiment, the glaze layer 12 has a bulging portion 121 and an auxiliary portion 122.

The bulging portion 121 has a band shape extending in the main scanning direction x, and has a cross-sectional arc shape slightly bulging upward in the drawing. The resistor layer 4 is formed on the bulging portion 121. The bulging portion 121 is for suppressing the heat generated from the heat generating portion 40 of the resistor layer 4 from being excessively transferred to the substrate 11.

The auxiliary portion 122 is formed so as to cover the portion of the substrate 11 exposed from the bulging portion 121. The bulging portion 121 is for forming a smooth surface suitable for forming the electrode layer 3 by covering the surface of the substrate 11, which is a relatively rough surface.

The bulging portion 121 and the auxiliary portion 122 are made of, for example, glass. The specific selection of such glass is made in view of fully exerting the heat storage function of the bulging portion 121 and the smoothing function of the auxiliary portion 122. As the material of the auxiliary portion 122, it is preferable to use a glass paste having a lower viscosity than the glass paste used as the material of the bulging portion 121.

The electrode layer 3 is for forming a path for energizing the resistor layer 4, and is formed of a conductive material. The material of the electrode layer 3 is not particularly limited, and is composed of Au or Pt to which rhodium, vanadium, bismuth, silicon or the like is added as an additive element, for example. In the present embodiment, the main component of the electrode layer 3 is Au. The electrode layer 3 is formed by printing a thick film of a paste of registered Au containing an organic compound and then firing the paste. Such an electrode layer 3 contains glass particles by undergoing a firing process. The electrode layer 3 may be formed by laminating a plurality of Au layers. The thickness of the electrode layer 3 is, for example, about 0.4 μm to 1.0 μm.

As shown in FIG. 3, the electrode layer 3 has a common electrode 33 and a plurality of individual electrodes 36.

The common electrode 33 has a plurality of common electrode band-shaped portions 34 and a common electrode connecting portion 35. The common electrode connecting portion 35 is arranged near the end on the downstream side in the sub-scanning direction y of the substrate 11, and has a band shape extending in the main scanning direction x. Each of the plurality of common electrode band-shaped portions 34 extends from the common electrode connecting portion 35 in the sub-scanning direction y, and is arranged at equal pitches in the main scanning direction x. Further, in the present embodiment, as shown in FIG. 4, the Ag layer 351 is laminated on the common electrode connecting portion 35. The Ag layer 351 is for reducing the resistance value of the common electrode connecting portion 35.

The plurality of individual electrodes 36 are for partially energizing the resistor layer 4, and are portions having opposite polarities with respect to the common electrode 33. The individual electrode 36 extends from the resistor layer 4 toward the drive IC 71. The plurality of individual electrodes 36 are arranged in the main scanning direction x, and each has an individual electrode band-shaped portion 38, an individual electrode connecting portion 37, and a bonding portion 39.

Each individual electrode band-shaped portion 38 is a band-shaped portion extending in the sub-scanning direction y, and is located between two adjacent common electrode band-shaped portions 34 of the common electrode 33. The width of the individual electrode band-shaped portion 38 of the individual electrode 36 and the common electrode band-shaped portion 34 of the common electrode 33 is, for example, 25 μm or less, and the individual electrode band-shaped portion 38 of the adjacent individual electrodes 36 and the common electrode of the common electrode 33 are common electrodes. The distance from the strip 34 is, for example, 40 μm or less.

The individual electrode connecting portion 37 is a portion extending from the individual electrode strip-shaped portion 38 toward the drive IC 71, and most of them have a portion along the sub-scanning direction y and a portion inclined with respect to the sub-scanning direction y. .. The width of most of the individual electrode connecting portions 37 is, for example, 40 μm or less, and the distance between adjacent individual electrode connecting portions 37 is, for example, 40 μm or less. In the illustrated example, the width of the individual electrode connecting portion 37 is larger than the width of the individual electrode strip-shaped portion 38.

The plurality of common electrode band-shaped portions 34 of the common electrode 33 and the individual electrode strip-shaped portions 38 of the plurality of individual electrodes 36 are formed on the bulging portion 121.

As shown in FIG. 3, the bonding portion 39 is formed at the y-end portion in the sub-scanning direction of the individual electrode 36, and the wire 61 for connecting the individual electrode 36 and the drive IC 71 is bonded. The bonding portions 39 of the adjacent individual electrodes 36 are arranged alternately in the sub-scanning direction y. As a result, the bonding portion 39 is prevented from interfering with each other even though the width of the bonding portion 39 is larger than that of most of the individual electrode connecting portions 37.

The portion of the individual electrode connecting portion 37 sandwiched between the adjacent bonding portions 39 has the smallest width in the individual electrode 36, and the width is, for example, 10 μm or less. Further, the distance between the individual electrode connecting portion 37 and the adjacent bonding portion 39 is, for example, 10 μm or less. As described above, the common electrode 33 and the plurality of individual electrodes 36 have a fine pattern in which the line width and the wiring interval are small.

The resistor layer 4 is made of, for example, ruthenium oxide, which has a higher resistivity than the material constituting the electrode layer 3, and is formed in a band shape extending in the main scanning direction x. The resistor layer 4 intersects the plurality of common electrode strips 34 of the common electrode 33 and the individual electrode strips 38 of the plurality of individual electrodes 36. Further, the resistor layer 4 is laminated on the side opposite to the substrate 11 with respect to the plurality of common electrode band-shaped portions 34 of the common electrode 33 and the individual electrode strip-shaped portions 38 of the plurality of individual electrodes 36. A portion of the resistor layer 4 sandwiched between each common electrode band-shaped portion 34 and each individual electrode strip-shaped portion 38 is a heat-generating portion 40 that generates heat when partially energized by the electrode layer 3. Print dots are formed by the heat generated by the heat generating portion 40. The thickness of the resistor layer 4 is, for example, 4 μm to 10 μm.

As shown in FIGS. 5 to 9, in the present embodiment, the resistor layer 4 has a pair of resistor side surfaces 41, a top surface 42, and a pair of resistor inclined surfaces 44.

The pair of resistor side surfaces 41 are located on both sides of the resistor layer 4 in the sub-scanning direction y, and are surfaces that stand upright in the direction in which the substrate 11 spreads (xy plane). The upright plane in the present specification is a plane having an angle of 90 ° with respect to the reference plane, but is intended not to include at least a plane that is gently connected to the reference plane. For example, as an example of the side surface 41 of the resistor, a surface having an angle α of about 80 ° to 90 ° shown in FIGS. 7 and 9 is referred to.

The top surface 42 is located between the pair of resistor side surfaces 41 and faces the side opposite to the substrate 11. In the present embodiment, the top surface 42 has a curved surface shape that bulges toward the side away from the substrate 11.

The pair of resistor inclined surfaces 44 are connected to the substrate 11 side with respect to the pair of resistor side surfaces 41, and are surfaces having a shape located outward in the sub-scanning direction y as they approach the substrate 11 in the thickness direction z. .. In the illustrated example, the resistor inclined surface 44 is a concave curved surface. Further, the dimension of the resistor inclined surface 44 in the thickness direction z is smaller than the dimension of the resistor side surface 41 in the thickness direction z.

In the present embodiment, as shown in FIGS. 5 and 12, the thermal print head A1 is provided with a plurality of covering bodies 48. In FIG. 5, for convenience of understanding, the resistor layer 4 is provided with hatches consisting of relatively light tone discrete points, and the covering 48 is provided with hatches consisting of relatively dark tone discrete points. doing. The plurality of covering bodies 48 are adjacent to at least one of the common electrode band-shaped portion 34 and the individual electrode strip-shaped portion 38 on both sides of the main scanning direction x on the bulging portion 121 of the glaze layer 12. That is, the covering body 48 covers the boundary between the bulging portion 121 of the glaze layer 12 and at least one of the common electrode strip-shaped portion 34 and the individual electrode strip-shaped portion 38. FIG. 12 shows a resistor inclined surface 44 adjacent to the individual electrode band-shaped portion 38, and a resistor inclined surface 44 similar to the resistor inclined surface 44 shown in the figure can be understood from FIG. Is provided adjacent to the common electrode band-shaped portion 34.

The covering body 48 is made of the same material as the resistor layer 4. The covering body 48 has a covering body inclined surface 49. The cover inclined surface 49 has a shape that is located outward in the main scanning direction as it approaches the substrate 11 in the thickness direction z. In the illustrated example, the covering inclined surface 49 is a concave curved surface. Further, the size and curvature of the covering inclined surface 49 may be the same as the size and curvature of the resistor inclined surface 44. As shown in FIG. 5, the covering body 48 is connected to the resistor layer 4 in the z-view in the thickness direction. The region of the common electrode strip-shaped portion 34 and the individual electrode strip-shaped portion 38 adjacent to the covering body 48 is a region within a predetermined distance in the sub-scanning direction y from the portion covered by the resistor layer 4. This region depends on the manufacturing method of the thermal print head A1 described later.

The protective layer 5 is for protecting the electrode layer 3 and the resistor layer 4. The protective layer 5 is made of, for example, amorphous glass. However, the protective layer 5 exposes a region including the bonding portion 39 of the plurality of individual electrodes 36.

The drive IC 71 functions to partially generate heat in the resistor layer 4 by selectively energizing a plurality of individual electrodes 36. The drive IC 71 is provided with a plurality of pads. The pad of the drive IC 71 and the plurality of individual electrodes 36 are connected to each other via a plurality of wires 61 bonded to each other. The wire 61 is made of Au. As shown in FIGS. 1 and 2, the drive IC 71 and the wire 61 are covered with the sealing resin 72. The sealing resin 72 is made of, for example, a black soft resin. Further, the drive IC 71 and the connector 73 are connected by a signal line (not shown).

Next, an example of a method for manufacturing the thermal print head A1 will be described below with reference to FIGS. 13 to 16.

First, as shown in FIGS. 13 and 14, a substrate 11 made of, for example, AlN is prepared. Next, a glass paste is printed on the substrate 11 as a thick film, and then the glass paste is fired to form a glaze layer 12 having a bulging portion 121 and an auxiliary portion 122. Next, a conductive paste printing step of thick-film printing the resinate Au paste is performed. Next, an electrode forming step is performed. In this step, a metal film is formed by firing the conductive paste. The thick film printing and firing steps may be repeated a plurality of times. Next, the electrode layer 3 is formed by performing patterning on the metal film by, for example, etching. The electrode layer 3 has a common electrode 33, a plurality of individual electrodes 36, and a plurality of bonding portions 39.

Next, a resistor paste printing step is performed in which a resistor paste 4A containing a resistor such as ruthenium oxide is printed in a thick film. In this step, the resistor paste 4A is printed so as to cross the plurality of common electrode strips 34 and the plurality of individual electrode strips 38 in the main scanning direction x. Further, the sub-scanning direction y dimension of the printed resistor paste 4A is sufficiently larger than that of the resistor layer 4 described above. As shown in FIG. 14, the surface of the thick film-printed resistor paste 4A is a curved surface that gently bulges in the thickness direction z. Further, both ends of the resistor paste 4A in the y direction are gently connected to the glaze layer 12, and are not standing portions.

Then, a drying step is performed. In this step, the resistor paste 4A is dried in an environment where the electrode layer 3 and the resistor paste 4A do not cause unintended deterioration or the like. This drying reduces the solvent contained in the resistor paste 4A. Such a dried resistor paste 4A maintains the cross-sectional shape shown in FIG. 14, but has a significantly brittle property as compared with that before drying.

Next, as shown in FIGS. 15 and 16, a removal step of removing both side portions of the dried resistor paste 4A in the sub-scanning direction is performed. The removal method in the removal step is not particularly limited, and shot blasting is used in the present embodiment. The mask 91 is made to face the support 1. The mask 91 is provided with a pair of penetrating portions 92. The pair of penetrating portions 92 are through holes each penetrating the mask 91 in the thickness direction z, and are provided apart from each other in the sub-scanning direction y. The distance between the pair of penetrating portions 92 is the sub-scanning direction y dimension of the resistor layer 4 to be formed.

A projection material is sprayed onto the resistor paste 4A from the pair of penetrating portions 92 in a state where the pair of penetrating portions 92 are overlapped on both ends of the sub-scanning direction y of the dried resistor paste 4A in the thickness direction z. The projection material is an appropriately selected granular material, and in the present embodiment, a material having a hardness that does not damage the electrode layer 3 and the glaze layer 12 while appropriately removing the dried resistor paste 4A is selected. Is preferable. Then, the mask 91 is moved with respect to the support 1 in the main scanning direction x while spraying the projection material from the pair of penetrating portions 92. As a result, both side portions in the sub-scanning direction y of the resistor paste 4A are continuously removed. The side surface formed by removing the resistor paste 4A becomes the pair of resistor side surfaces 41 described above. Further, a part of the surface of the resistor paste 4A becomes the above-mentioned top surface 42. The remaining resistor paste 4A has substantially the same shape and dimensions as the resistor layer 4 to be formed in the z-view in the thickness direction.

The projection material, which is a granular material, has a predetermined average particle size. Therefore, concave curved surfaces having an average radius corresponding to the average particle size of the projecting material can be formed at both ends of the sub-scanning direction y of the resistor paste 4A remaining after the removal step. This concave curved surface becomes the above-mentioned resistor inclined surface 44. Further, in the resistor paste 4A, the portion adjacent to the common electrode strip-shaped portion 34 and the individual electrode strip-shaped portion 38 in the main scanning direction x is largely removed by shot blasting, but the average particle size of the projecting material is increased. A resistor paste 4A having a concave curved surface having a corresponding average radius may remain adjacent to the common electrode strip 34 and the individual electrode strip 38. The remaining resistor paste 4A becomes the covering body 48 having the covering body inclined surface 49 described above.

Next, a resistor layer forming step is performed. In this step, the dried resistor paste 4A is fired at a predetermined temperature. As a result, the resistor layer 4 having the above-described configuration is obtained. Further, when the resistor paste 4A remains adjacent to the common electrode band-shaped portion 34 and the individual electrode strip-shaped portion 38, the resistor paste 4A becomes the covering body 48 described above.

After that, for example, a glass paste is printed in a thick film and fired to form the protective layer 5. Then, the thermal print head A1 can be obtained by mounting the drive IC 71, bonding the wires 61, attaching the substrate 11 and the wiring board 74 to the heat radiating member 75, and the like.

Next, the operation of the thermal print head A1 and the method of manufacturing the thermal print head A1 will be described.

According to this embodiment, the resistor layer 4 has a pair of resistor side surfaces 41. The resistor layer 4 is a layer that generates heat when energized, and is desired to have a predetermined resistance value. In order to achieve this predetermined value, it is necessary to secure a cross-sectional area of the resistor layer 4 perpendicular to the main scanning direction x in a predetermined area or more. When the resistor layer 4 is formed by thick film printing, the printed resistor paste has a shape having a curved surface in which the surface is gently bulged. Therefore, the central portion of the resistor layer 4 in the sub-scanning direction y is significantly thicker than the portions at both ends in the sub-scanning direction y. In the case of the resistor layer 4 having such a shape, even if a predetermined area is secured and a predetermined resistance value is achieved, the current at the time of energization selectively flows in the relatively thick sub-scanning direction y central portion. Therefore, the central portion of the resistor layer 4 in the sub-scanning direction y generates heat intensively, and the portions on both sides of the sub-scanning direction y hardly contribute to heat generation. In this respect, since the resistor layer 4 of the present embodiment has a pair of resistor side surfaces 41, the thickness of the sub-scanning direction y central portion and the sub-scanning direction y both side portions is thick when the cross-sectional area is a predetermined area. It is possible to reduce the difference in the z dimension in the longitudinal direction. As a result, it is possible to generate heat more efficiently on both sides of the resistor layer 4 in the sub-scanning direction y. Therefore, the resistor layer 4 can be generated more uniformly.

Further, when the predetermined cross-sectional area is secured by reducing the difference in the thickness direction z dimension between the sub-scanning direction y central portion and the sub-scanning direction y both side portions of the resistor layer 4. It is possible to reduce the thickness of the central portion in the sub-scanning direction y.

Since the top surface 42 has a gentle convex curved surface, the surface of the protective layer 5 covering the top surface 42 can easily be a gentle convex curved surface. This is preferable for smoothly sliding the thermal print head A1 and the printing paper.

In the production of the thermal print head A1, as shown in FIGS. 13 and 14, the resistor paste 4A printed by the resistor paste printing step is dried in the drying step. Then, the resistor paste 4A, which has become brittle after the drying step, is partially removed by the removing step. Therefore, in the removing step, the desired portion to be removed of the resistor paste 4A can be easily removed. Further, in order to remove the resistor paste 4A, it is not necessary to adopt a removal method that exerts a particularly powerful removing function. Therefore, there is an advantage that the electrode layer 3 and the glaze layer 12 are less likely to be unduly damaged in the removing step.

If shot blasting is used in the removing step, the desired portion of the resistor paste 4A can be reliably removed. Further, as shown in FIGS. 15 and 16, the resistor after being removed by performing shot blasting while moving the pair of penetrating portions 92 relative to the resistor paste 4A in the main scanning direction x. The side surface y in the sub-scanning direction of the paste 4A has a flatness equivalent to the accuracy of moving the mask 91. This side surface is a portion of the resistor layer 4 that becomes the resistor side surface 41, and is suitable for further increasing the flatness of the resistor side surface 41 and forming the shape along the main scanning direction x.

Further, the resistor layer 4 has a resistor inclined surface 44. The resistor inclined surface 44 expands the joining area at the joining portion between the resistor layer 4 and the electrode layer 3 and the glaze layer 12. Therefore, it is preferable to improve the bonding strength of the resistor layer 4. Further, when stress is generated at the joint between the resistor layer 4 and the electrode layer 3 or the glaze layer 12 due to heat generation of the heat generating portion 40 of the resistor layer 4 in the use of the thermal print head A1, this It can be expected to relieve stress.

The covering body 48 is adjacent to the common electrode strip-shaped portion 34 and the individual electrode strip-shaped portion 38 in the main scanning direction x. Therefore, the covering body 48 is shaped to cover the joint portion between the common electrode band-shaped portion 34 and the individual electrode strip-shaped portion 38 and the glaze layer 12. With such a covering body 48, the joint strength between the common electrode strip-shaped portion 34 and the individual electrode strip-shaped portion 38 and the glaze layer 12 can be increased. Further, as shown in FIGS. 13 to 16, the covering body 48 is a portion of the resistor paste 4A in which a region that has been shot blasted or the like by the removing step remains partially. Therefore, the covering body 48 is connected to the resistor layer 4 in the z-view in the thickness direction. The common electrode band-shaped portion 34 and the individual electrode strip-shaped portion 38 connected to the resistor layer 4 in the sub-scanning direction y are subjected to a temperature cycle by the heat generated by the heat generating portion 40. By providing the covering body 48 adjacent to the common electrode band-shaped portion 34 and the individual electrode strip-shaped portion 38 at such positions, unintentional peeling or the like of the common electrode band-shaped portion 34 and the individual electrode strip-shaped portion 38 can be avoided. be able to. According to the removal step using shot blasting, the resistor inclined surface 44 and the covering body 48 of the resistor layer 4 can be rationally formed. The resistor inclined surface 44 and the covering body 48 can be formed, for example, in a removal step using shot blasting, and the resistor inclined surface 44 and the covering body 48 may be formed depending on conditions such as the properties of the projection material used for shot blasting. The configuration may not include either one or both of the coverings 48.

17 to 24 show other embodiments of the present invention. In these figures, the same or similar elements as those in the above embodiment are designated by the same reference numerals as those in the above embodiment.

FIG. 17 shows a thermal printhead based on the second embodiment of the present invention. In the thermal print head A2 of the present embodiment, the configuration of the top surface 42 of the resistor layer 4 is different from that of the above-described embodiment.

In the present embodiment, the top surface 42 has a recess 43. The recess 43 is located at the center of the top surface 42 in the sub-scanning direction y, and is a recessed portion on the substrate 11 side. The resistor layer 4 having such a recess 43 is, for example, shot blasted using a mask 91 having a penetrating portion 93 as shown in FIG. 18 after shot blasting in the removal step shown in FIGS. 15 and 16. It can be formed by doing. The penetrating portion 93 is located at the center of the resistor paste 4A that has undergone the removal step in the sub-scanning direction y. The mask 91 is moved in the main scanning direction x while spraying the projection material from the penetrating portion 93. The projecting material sprayed from the penetrating portion 93 has a strength that slightly reduces the z dimension in the thickness direction of the resistor paste 4A.

Even in such an embodiment, the resistor layer 4 can be heated more uniformly. Further, by having the recess 43, when the resistor layer 4 is energized, a larger current can be passed through the sub-scanning direction y both sides of the resistor layer 4. Since the central portion of the resistor layer 4 in the sub-scanning direction y is a portion sandwiched between the sub-scanning directions y and both side portions of the resistor layer 4, the degree of heat dissipation is relatively small. In other words, the degree of heat dissipation is relatively large in the sub-scanning direction y both side portions of the resistor layer 4. By passing a larger amount of current to both sides of the sub-scanning direction y, heat can be uniformly transferred to the printing paper, which is advantageous for clearer printing.

FIG. 19 shows a thermal printhead based on the third embodiment of the present invention. In the thermal print head A3 of the present embodiment, the configuration of the top surface 42 of the resistor layer 4 is different from that of the above-described embodiment.

In the present embodiment, the top surface 42 is a flat surface and is along the main scanning direction x and the sub scanning direction y. The angle α is in the same range as that of the above-described embodiment, but may be larger than the angle α in the thermal print head A1 and the thermal print head A2.

Further, in the present embodiment, the resistor layer 4 does not have the resistor inclined surface 44. Further, in the thermal print head A3, the covering body 48 is not formed.

FIG. 20 shows an example of a method for manufacturing the thermal print head A3. In the manufacturing method of the present embodiment, the resistor printing steps shown in FIGS. 20 and 21 are performed. In the illustrated example, the resistor paste 4A is printed on the intermediate support 97 by a screen printing technique using a screen 95 and a squeegee 96. The intermediate support 97 is a cylindrical member, and a material that absorbs the solvent of the resistor paste 4A is provided on the peripheral surface thereof. Examples of such a material include silicone. Each of the plurality of resistor pastes 4A printed on the intermediate support 97 in FIG. 21 serves as the resistor layer 4, and the paper surface depth direction is the main scanning direction x.

The solvent of the resistor paste 4A printed on the intermediate support 97 by the resistor printing step is absorbed by the intermediate support 97. This is the solvent absorption step. When the solvent is absorbed by the solvent absorption step, the shape change of the resistor paste 4A thereafter is suppressed.

Next, the transfer steps shown in FIGS. 22 and 23 are performed. As shown in FIG. 22, the support material 1A is prepared. The support material 1A is a material capable of forming a plurality of supports 1. The support material 1A has a substrate material 11A and a glaze layer 12. The substrate material 11A is a material capable of forming a plurality of substrates 11. The substrate material 11A is formed with bulging portions 121 (glaze layer 12) corresponding to bulging portions 121 of the plurality of supports 1. Further, a plurality of electrode layers 3 (not shown) are formed on the support material 1A.

The intermediate support 97 on which the plurality of resistor pastes 4A are printed is made to face the support material 1A, and is rotated while being relatively moved with respect to the support material 1A. At this time, the plurality of resistor pastes 4A are moved and rotated so as to be transferred to the plurality of bulging portions 121 separately. As a result, the resistor paste 4A in which the solvent has been absorbed is transferred to the bulging portion 121 of the support material 1A.

After that, the resistor paste 4A transferred to the support material 1A is fired to perform a resistor layer forming step to form the resistor layer 4. Then, the support material 1A is divided to obtain a plurality of supports 1. Then, the thermal print head A3 can be obtained by going through the same steps as the thermal print head A1 described above.

Also in this embodiment, the resistor layer 4 can be generated more uniformly. Since the top surface 42 of the resistor layer 4 is flat, it is possible to make the z dimension of the resistor layer 4 in the thickness direction more uniform. Further, it is preferable to make the surface of the protective layer 5 covering the resistor layer 4 close to flat.

The resistor paste 4A printed on the intermediate support 97 in the printing step absorbs the solvent in the solvent absorbing step. As a result, the shape of the resistor paste 4A formed in the printing process is maintained almost as it is. As a result, the resistor paste 4A transferred to the support material 1A is less likely to drip into a shape having a gentle curved surface or the like. Therefore, the resistor layer 4 having a flat top surface 42 can be appropriately formed.

FIG. 24 shows a thermal printhead based on the fourth embodiment of the present invention. The structure of the glaze layer 12 of the thermal print head A4 of the present embodiment is different from that of the above-described embodiment.

In the present embodiment, the glaze layer 12 does not have the above-mentioned bulging portion 121, and has a substantially uniform thickness covering the entire surface of the substrate 11. As described above, also in the thermal print heads A1 to A3 described above, the glaze layer 12 having no bulging portion 121 may be adopted.

The thermal print head and the method for manufacturing the thermal print head according to the present invention are not limited to the above-described embodiments. The specific configuration of the thermal print head and the method for manufacturing the thermal print head according to the present invention can be freely redesigned in various ways.

A1 to A4: Thermal print head 1: Support 1A: Support material 3: Electrode layer 4: Resistor layer 4A: Resistor paste 5: Protective layer 11: Substrate 11A: Substrate material 12: Glaze layer 33: Common electrode 34 : Common electrode strip-shaped portion 35: Common electrode connecting portion 36: Individual electrode 37: Individual electrode connecting portion 38: Individual electrode strip-shaped portion 39: Bonding portion 40: Heat generating portion 41: Resistor side surface 42: Top surface 43: Recessed portion 44: Resistance Body inclined surface 48: Cover 49: Cover inclined surface 61: Wire 71: Drive IC
72: Encapsulating resin 73: Connector 74: Wiring board 75: Heat dissipation member 81: Platen roller 82: Thermal paper 91: Mask 92: Penetration part 93: Penetration part 95: Screen 96: Squeegee 97: Intermediate support 121: Swelling Part 122: Auxiliary part 351: Ag layer x: Main scanning direction y: Sub-scanning direction z: Thickness direction α: Angle

Claims (12)

A support including a substrate and
With the electrode layer
A thermal printhead comprising a plurality of heat generating portions arranged in the main scanning direction and a resistor layer covering at least a part of the electrode layer.
The resistor layer is a strip extending in the main scanning direction, have a pair of resistors sides standing upright with respect to the spreading direction is the substrate in the sub-scanning direction on both sides,
The electrode layer includes a plurality of common electrode strips each extending in the sub-scanning direction and spaced apart from each other in the main scanning direction, and the common electrode strips each extending in the sub-scanning direction and adjacent to each other. It has a plurality of individual electrode strips arranged separately between them, and has a plurality of individual electrode strips.
The resistor layer covers the plurality of common electrode strips and the plurality of individual electrode strips so as to traverse the main scanning direction.
The resistor layer has a pair of resistor inclined surfaces that are connected to the substrate side with respect to the pair of resistor side surfaces and are positioned outward in the sub-scanning direction as they approach the substrate.
The shape is adjacent to at least one of the common electrode band-shaped portion and the individual electrode strip-shaped portion on both sides in the main scanning direction, is made of the same material as the resistor layer, and is located outside the main scanning direction as it approaches the substrate. further comprising wherein the Rukoto a coating having a coating body inclined surface, the thermal print head. The thermal print head according to claim 1 , wherein the resistor layer has a top surface located between the pair of resistor side surfaces in the sub-scanning direction. The thermal print head according to claim 2 , wherein the top surface has a curved surface shape that bulges toward a side away from the substrate. The thermal print head according to claim 2 , wherein the top surface has a recess recessed on the substrate side. The thermal print head according to claim 2 , wherein the top surface is a flat surface. The thermal print head according to any one of claims 1 to 5, wherein the dimension of the inclined surface of the resistor in the thickness direction of the substrate is smaller than the dimension of the side surface of the resistor in the thickness direction. The thermal print head according to any one of claims 1 to 6, wherein the covering body is connected to the resistor layer in the thickness direction of the substrate. The thermal printhead according to any one of claims 1 to 7 , wherein the support further includes a glaze layer interposed between the substrate, the electrode layer, and the resistor layer. The thermal print head according to claim 8 , wherein the glaze layer includes a bulging portion located between the resistor layer and the substrate and bulging toward a side away from the substrate. A conductive paste printing process that prints a conductive paste on a support including a substrate,
An electrode layer forming step of forming an electrode layer by firing the conductive paste, and
A resistor paste printing step of printing a resistor paste so as to cover at least a part of the electrode layer.
A drying step of drying the resistor paste and
A removal step of removing both side portions of the dried resistor paste in the sub-scanning direction, and
A resistor layer forming step of forming a resistor layer by firing the resistor paste is provided .
In the removal step, shot blasting is used.
After it said drying step, prior to the resistor layer formation step further comprises characterized Rukoto a recess forming step of recessing the portion of the resistor paste by shot blasting method for producing a thermal printing head. In the removal step, using a mask having a pair of penetrating portions separated in the sub-scanning direction, the pair of penetrating portions are moved from the pair of penetrating portions with respect to the resistor paste in the main scanning direction. The method for manufacturing a thermal print head according to claim 10 , wherein a projection material is sprayed. A conductive paste printing process that prints a conductive paste on a support including a substrate,
An electrode layer forming step of forming an electrode layer by firing the conductive paste, and
A resistor paste printing step of printing a resistor paste so as to cover at least a part of the electrode layer.
A drying step of drying the resistor paste and
A removal step of removing both side portions of the dried resistor paste in the sub-scanning direction, and
A resistor layer forming step of forming a resistor layer by firing the resistor paste is provided.
In the electrode layer forming step, a plurality of common electrode strips extending in the sub-scanning direction and spaced apart from each other in the main scanning direction, and each extending in the sub-scanning direction, are formed in the electrode layer. A plurality of individual electrode strips arranged separately between the adjacent common electrode strips are formed.
In the resistor paste printing step, the resistor paste is printed so as to cross the plurality of common electrode strips and the plurality of individual electrode strips in the main scanning direction.
In the removal step, shot blasting is used.
A pair of resistor side surfaces that stand up in the direction in which the substrate spreads on both sides of the resistor layer in the sub-scanning direction, and sub-scanning that is connected to the substrate side with respect to the pair of resistor side surfaces and approaches the substrate. A pair of resistor inclined surfaces having a shape located outside the direction are formed, and
The shape is adjacent to at least one of the common electrode band-shaped portion and the individual electrode strip-shaped portion on both sides in the main scanning direction, is made of the same material as the resistor layer, and is located outside the main scanning direction as it approaches the substrate. A method of manufacturing a thermal print head, which comprises forming a covering having an inclined surface of the covering.

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