JP5820107B2 - Thermal print head and manufacturing method thereof - Google Patents

Description

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

  FIG. 37 shows an example of a conventional thermal print head (see, for example, Patent Document 1). The thermal print head 900 shown in the figure has a ceramic substrate 91 and a wiring substrate 92. A glaze layer 93 is formed on the ceramic substrate 91. The glaze layer 93 is made of glass, for example, and has a circular cross section that is perpendicular to the main scanning direction. An electrode layer 94 is formed on the ceramic substrate 91. The electrode layer 94 is mainly composed of Au, for example, and has a plurality of individual electrodes 941 and a common electrode 942. A resistor layer 95 and a protective layer 96 are stacked on the electrode layer 94. The resistor layer 95 is formed so as to straddle the individual electrode 941 and the common electrode 942. The protective layer 96 is for protecting the electrode layer 94 and the resistor layer 95, and is made of, for example, glass. A drive IC 97 is mounted on a portion of the ceramic substrate 91 near one end in the sub-scanning direction. The drive IC 97 functions to partially energize the resistor layer 95 through the plurality of individual electrodes 941. The drive IC 97 is connected to the plurality of individual electrodes 941 and the wiring substrate 92 by wires 98.

  Thermal paper that is a printing target is pressed against the resistor layer 95 through the protective layer 96. This pressing is performed by a platen roller (not shown) provided in a printer in which the thermal print head 900 is incorporated. When the pressing force by the platen roller reaches the region where the individual electrode 941 and the common electrode 942 are provided, the portion of the resistor layer 95 covering the individual electrode 941 and the common electrode 942 may be damaged. Patent Document 1 proposes a configuration in which the individual electrode 941 and the common electrode 942 are settled with respect to the glaze layer 93. However, as the thermal print head 900 becomes thinner, the thinner the glaze layer 93, the more difficult it is for the individual electrode 941 and the common electrode 942 to settle. In such a case, damage to the resistor layer 95 could not be sufficiently avoided.

No. 2005-120841

  The present invention has been conceived under the circumstances described above, and an object thereof is to provide a thermal print head capable of avoiding damage to the resistor layer and a manufacturing method thereof.

  A thermal print head provided by the first aspect of the present invention is formed on a substrate and the substrate, and extends in a main scanning direction in which a cross-sectional shape perpendicular to the main scanning direction is an arc shape. A glaze layer having a heating resistor support, and a plurality of pairs of strips arranged in the main scanning direction, each comprising a pair of strips spaced apart from each other in the sub-scanning direction on the heating resistor support. And a resistor layer having a heat generating portion that covers a gap between each pair of strip-shaped portions, wherein the strip-shaped portion has a normal thickness portion and is more than the normal thickness portion. And a thin-walled portion located on the gap side.

  In a preferred embodiment of the present invention, the thin portion is a thermal print head according to claim 1, wherein the thin portion is settled with respect to the heating resistor support portion.

  In a preferred embodiment of the present invention, the electrode layer includes a main body Au layer composed of a lower layer and an upper layer laminated on the lower layer, and the normal thickness portion is constituted by the lower layer and the upper layer. And the said thin part is comprised by the said lower layer.

  In a preferred embodiment of the present invention, the electrode layer includes a main body Au layer composed of a lower layer and an upper layer laminated on the lower layer, and the normal thickness portion is constituted by the lower layer and the upper layer. And the said thin part is comprised by the said upper layer.

  In a preferred embodiment of the present invention, the electrode layer includes two strips located on the same side in the sub-scanning direction among the two pairs of strips adjacent in the main scanning direction, and the strips. A plurality of relay electrodes having connecting portions to be connected; a plurality of individual electrodes each having one band-shaped portion of each of the relay electrodes; and the band-shaped portions constituting the pair of band-shaped portions; The other belt-shaped portion of the electrode and a common electrode having a plurality of the belt-shaped portions constituting the pair of belt-shaped portions.

  In a preferred embodiment of the present invention, the common electrode includes two strips adjacent to each other in the main scanning direction and a branch portion connected to the strips, and the common electrode includes the two strips. The two strips constitute the pair of strips separately from the strips of the two relay electrodes.

  In a preferred embodiment of the present invention, the electrode layer comprises a plurality of individual electrodes each having one of the pair of strips, and the strips and the pairs of strips of the individual electrodes. And a common electrode having a connecting portion that connects these belt-like portions.

  In preferable embodiment of this invention, the Ag layer which overlaps with the said connection part, and the Ag protective layer which covers the said Ag layer are further provided.

  In a preferred embodiment of the present invention, the Ag protective layer is made of glass.

  In a preferred embodiment of the present invention, the common electrode has a backbone portion that is located farther from the plurality of individual electrodes with respect to the heating resistor support portion in the sub-scanning direction. The unit supports a drive IC for selectively energizing the plurality of individual electrodes.

  In a preferred embodiment of the present invention, a resin layer is interposed between the drive IC and the backbone part.

  In a preferred embodiment of the present invention, the substrate is made of ceramic.

  In preferable embodiment of this invention, the said board | substrate is further provided with the heat sink made from a metal.

  The thermal printhead manufacturing method provided by the second aspect of the present invention includes a heating resistor support portion extending in the main scanning direction on a substrate, the cross-sectional shape of which is perpendicular to the main scanning direction being an arc. And a plurality of pairs of strips arranged in the main scanning direction, each of which is formed of a pair of strips spaced apart from each other in the sub-scanning direction on the heating resistor support portion. A method of manufacturing a thermal print head, comprising: forming an electrode layer; and forming a resistor layer having a heat generating portion that covers a gap between the pair of belt-like portions, and forming the electrode layer In the process, the band-shaped part is formed so as to have a normal thick part and a thin part that is thinner than the normal thick part and located on the gap side.

  In a preferred embodiment of the present invention, after the step of forming the electrode layer and before the step of forming the resistor layer, the band-shaped portion is formed by heating the heating resistor support portion to form the heating resistor. It further has the process of settling with respect to a body support part.

  In a preferred embodiment of the present invention, in the step of forming the electrode layer, a main body Au layer composed of a lower layer and an upper layer laminated on the lower layer is formed, and the normal thickness portion is formed on the lower layer and the upper layer. It is comprised by an upper layer, and the said thin part is comprised by the said lower layer.

  In a preferred embodiment of the present invention, in the step of forming the electrode layer, a main body Au layer composed of a lower layer and an upper layer laminated on the lower layer is formed, and the normal thickness portion is formed on the lower layer and the upper layer. The upper layer is configured, and the thin portion is configured by the upper layer.

  In a preferred embodiment of the present invention, the step of forming the electrode layer includes a step of baking a paste containing Au and then baking the paste.

  In a preferred embodiment of the present invention, the step of forming the resistor layer uses a sputtering method or a CVD method.

  In a preferred embodiment of the present invention, in the step of forming the electrode layer, a plurality of individual electrodes each having one of the pair of strips, the strips of the individual electrodes, and the pairs And forming a common electrode having a plurality of strip-shaped portions constituting the strip-shaped portion and a connecting portion connecting these strip-shaped portions, and before the step of forming the resistor layer after the step of forming the electrode layer In addition, after printing the Ag paste so as to overlap the connecting portion, baking the Ag paste to form an Ag layer, and after forming the Ag layer, forming the resistor layer Before, it has further the process of forming an Ag protective layer by baking this glass paste, after printing glass paste so that the said Ag layer may be covered.

  In a preferred embodiment of the present invention, at least one of the step of firing the Ag paste and the step of firing the glass paste also serves as a step of allowing the strip-shaped portion to settle with respect to the heating resistor support portion. .

  According to such a configuration, it is possible to suppress a significant step at the boundary between the tip of the belt-like portion and the heating resistor support portion of the glaze layer. This is to prevent the resistor layer from covering a significant step and is suitable for avoiding damage to the resistor layer.

  Other features and advantages of the present invention will become more apparent from 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 a principal part top view which shows the thermal print head of FIG. It is sectional drawing which follows the III-III line of FIG. It is principal part sectional drawing in alignment with the III-III line of FIG. It is principal part sectional drawing in alignment with the III-III line of FIG. It is principal part sectional drawing which shows the state which formed the glaze layer in the board | substrate in an example of the manufacturing method of the thermal print head of FIG. It is principal part sectional drawing which shows the state which formed the glaze layer in the board | substrate in an example of the manufacturing method of the thermal print head of FIG. It is principal part sectional drawing which shows the state in which the glass layer was formed in an example of the manufacturing method of the thermal print head of FIG. It is principal part sectional drawing which shows the state in which the lower layer of main body Au layer was formed in an example of the manufacturing method of the thermal print head of FIG. It is principal part sectional drawing which shows the state in which the lower layer of main body Au layer was formed in an example of the manufacturing method of the thermal print head of FIG. FIG. 2 is a cross-sectional view of a main part showing a state in which an upper layer of a main body Au layer is formed in an example of the method for manufacturing the thermal print head of FIG. 1. FIG. 2 is a cross-sectional view of a main part showing a state in which an upper layer of a main body Au layer is formed in an example of the method for manufacturing the thermal print head of FIG. 1. FIG. 2 is a cross-sectional view of a main part showing a state in which an auxiliary Au layer is formed in an example of the method for manufacturing the thermal print head of FIG. 1. FIG. 3 is a plan view of a principal part showing a state in which an auxiliary Au layer is formed in an example of the method for manufacturing the thermal print head of FIG. 1. FIG. 2 is a plan view of a principal part showing a state in which a main body Au layer and an auxiliary Au layer are etched in an example of the method for manufacturing the thermal print head of FIG. 1. It is sectional drawing which follows the XVI-XVI line | wire of FIG. It is sectional drawing which follows the XVI-XVI line | wire of FIG. It is principal part sectional drawing which shows the state which settled the strip | belt-shaped part in an example of the manufacturing method of the thermal print head of FIG. FIG. 2 is a plan view of a principal part showing a state in which a resistor layer is formed in an example of the method for manufacturing the thermal print head of FIG. 1. It is sectional drawing which follows the XX-XX line of FIG. FIG. 7 is a plan view of a principal part showing a state in which the resistor layer is etched in an example of the method for manufacturing the thermal print head of FIG. 1. It is sectional drawing which follows the XXII-XXII line | wire of FIG. It is principal part sectional drawing which shows the state in which the lower layer of the protective layer was formed in an example of the manufacturing method of the thermal print head of FIG. It is principal part sectional drawing which shows the state which formed the upper layer of the protective layer in an example of the manufacturing method of the thermal print head of FIG. It is principal part sectional drawing which shows the state in which the resin layer was formed in an example of the manufacturing method of the thermal print head of FIG. FIG. 2 is a cross-sectional view of a principal part showing a state where a drive IC is mounted in an example of the method for manufacturing the thermal print head of FIG. 1. It is principal part sectional drawing which shows the modification of the thermal print head based on 1st Embodiment of this invention. FIG. 28 is a fragmentary cross-sectional view showing a state in which a lower layer of a main body Au layer is formed in an example of the method for manufacturing the thermal print head of FIG. 27. FIG. 28 is a fragmentary cross-sectional view showing a state in which the upper layer of the main body Au layer is formed in an example of the method for manufacturing the thermal print head of FIG. 27. FIG. 28 is a cross-sectional view of an essential part showing a state in which the main body Au layer and the auxiliary Au layer are etched in the example of the manufacturing method of the thermal print head of FIG. 27. It is principal part sectional drawing which shows the state which settled the strip | belt-shaped part in an example of the manufacturing method of the thermal print head of FIG. It is a principal part top view which shows the thermal print head based on 2nd Embodiment of this invention. It is sectional drawing which follows the XXXIII-XXXIII line | wire of FIG. FIG. 32 is a cross-sectional view of a principal part showing a state in which the main body Au layer and the auxiliary Au layer are etched in the example of the manufacturing method of the thermal print head of FIG. 31. FIG. 32 is an essential part cross-sectional view showing a state in which an Ag layer is formed in an example of the method for manufacturing the thermal print head of FIG. 31. FIG. 32 is an essential part cross-sectional view showing a state in which an Ag protective layer is formed in an example of the method for producing the thermal print head of FIG. 31. It is principal part sectional drawing which shows an example of the conventional thermal print head.

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

  1 to 5 show a thermal print head according to a first embodiment of the present invention. The thermal print head 101 of this embodiment includes a support unit 1, a glaze layer 2, an electrode layer 3, a resistor layer 4, a protective layer 5, a resin layer 6, a drive IC 7, and a sealing resin 82. The thermal print head 101 is incorporated in a printer that performs printing on thermal paper in order to create, for example, a barcode sheet or a receipt. For convenience of understanding, the protective layer 5 and the resin layer 6 are omitted in FIG. 1, and a part of the resin layer 6 and the sealing resin 82 are omitted in FIG. This is indicated by the dotted line.

The support unit 1 is a part that is a base of the thermal print head 101, and includes a ceramic substrate 11, a wiring substrate 12, and a heat sink 13. The ceramic substrate 11 is made of ceramic such as Al ₂ O ₃ and has a thickness of about 0.6 to 1.0 mm, for example. As shown in FIG. 1, the ceramic substrate 11 has a long rectangular shape extending long in the main scanning direction x. The wiring board 12 has a structure in which, for example, a base material layer made of glass epoxy resin and a wiring layer made of Cu or the like are laminated. As shown in FIG. 3, a connector 83 for connecting the thermal print head 101 to the printer is attached to the wiring board 12. The heat radiating plate 13 is for radiating heat from the ceramic substrate 11 and is made of a metal such as Al.

  The glaze layer 2 is formed on the ceramic 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 2 has a heating resistor support 21 and an IC electrode support 22. The heating resistor support portion 21 extends long in the main scanning direction x as shown in FIG. 2, and as shown in FIGS. 3 and 4, the sectional shape of the yz plane including the sub-scanning direction y and the thickness direction z. Has an arc shape. The size of the heating resistor support 21 is, for example, about 700 μm in the sub-scanning direction y, and about 18-50 μm in the thickness direction z. The heating resistor support 21 is provided to press a portion of the resistor layer 4 that generates heat against thermal paper or the like to be printed. The IC electrode support portion 22 is provided at a position separated from the heating resistor support portion 21 in the sub-scanning direction y, and supports a part of the electrode layer 3 and the drive IC 7. The thickness of the IC electrode support portion 22 is, for example, about 1.7 to 1.8 μm.

  A region sandwiched between the heating resistor support 21 and the IC electrode support 22 in the ceramic substrate 11 is covered with a glass layer 25. The glass layer 25 is made of glass having a softening point of, for example, about 680 ° C. and a softening point lower than that of the glass forming the glaze layer 2. The thickness of the glass layer 25 is, for example, about 2.0 μm. As shown in FIGS. 3 and 4, a part of the left side of the ceramic substrate 11 in the drawing of the heating resistor support 21 is covered with a glass layer 26. The glass layer 26 has the same material and thickness as the glass layer 25.

  The electrode layer 3 is used to form a path for energizing the resistor layer 4. In the present embodiment, the electrode layer 3 includes a main body Au layer 301 and an auxiliary Au layer 304. For example, rhodium, vanadium, bismuth, silicon, or the like is added as an additive element. In the present embodiment, the main body Au layer 301 includes a lower layer 302 and an upper layer 303. Each of the lower layer 302 and the upper layer 303 has a thickness of about 0.3 μm, for example. The auxiliary Au layer 304 is laminated on the main body Au layer 301 and is made of resinate Au having an Au ratio of about 99.7%, for example. The auxiliary Au layer 304 has a thickness of about 0.3 μm. In addition to the materials described above, the auxiliary Au layer 304 may be made of a material having an Au ratio of about 60% and glass frit mixed therein, for example. In this case, the auxiliary Au layer 304 has a thickness of about 1.1 μm.

  The electrode layer 3 has a plurality of individual electrodes 33, a plurality of relay electrodes 37, and a common electrode 35.

  The plurality of individual electrodes 33 are for partially energizing the resistor layer 4. Each individual electrode 33 has a band-shaped portion 331, a bent portion 333, a straight portion 334, a skew portion 335, and a bonding portion 336. The belt-like portion 331 is a belt-like shape extending along the sub-scanning direction y and is located on the heating resistor support portion 21. The opposing edge 332 of the band-shaped portion 331 is along the main scanning direction x. The bent part 333 is a part connected to the belt-like part 331 and has a part inclined with respect to both the main scanning direction x and the sub-scanning direction y. In the present embodiment, the bent portion 333 is formed on the heating resistor support portion 21. The straight part 334 extends straight in parallel to the sub-scanning direction y. Most of the direct part 334 is formed on the glass layer 25, and one end side part overlaps the heating resistor support part 21 and the other end part overlaps the IC electrode support part 22. The oblique portion 335 extends in a direction inclined with respect to both the main scanning direction x and the sub-scanning direction y, and is formed on the IC electrode support portion 22. The bonding part 336 is a part to which the wire 81 is bonded, and is formed on the IC electrode support part 22. In the present embodiment, the width of the band-shaped portion 331, the bent portion 333, the straight portion 334, and the skew portion 335 is set to, for example, about 47.5 μm, and the width of the bonding portion 336 is set to, for example, about 80 μm. .

  The common electrode 35 is a portion that is electrically opposite in polarity to the plurality of individual electrodes 33, and includes a plurality of strip-shaped portions 351, a plurality of branch portions 353, a plurality of orthogonal portions 354, a plurality of skewed portions 355, and a plurality of The extended portion 356 and the backbone portion 357 are provided. Each of the plurality of belt-like portions 351 has a belt-like shape extending in the sub-scanning direction y, and is located on the heating resistor support portion 21. The opposing edge 352 of the strip 351 is along the main scanning direction x. In the present embodiment, two band-like portions 351 adjacent to each other are disposed between the two band-like portions 331. The branch part 353 is a part that connects the two belt-like parts 351 and one orthogonal part 354, and has a Y-shape. The branch part 353 is formed on the heating resistor support part 21. The direct part 354 extends straight in parallel to the sub-scanning direction y. Most of the direct portion 354 is formed on the glass layer 25, and one end side portion overlaps the heating resistor support portion 21 and the other end portion overlaps the IC electrode support portion 22. The oblique portion 355 extends in a direction inclined with respect to both the main scanning direction x and the sub-scanning direction y, and is formed on the IC electrode support portion 22. The extension part 356 is a part connected to the skew part 355 and extends along the sub-scanning direction y. The trunk portion 357 has a strip shape extending in the main scanning direction x, and a plurality of extending portions 356 are connected. In the present embodiment, the widths of the belt-like portion 351, the straight portion 354, the skew portion 355, and the extending portion 356 are, for example, about 47.5 μm.

  The plurality of relay electrodes 37 are electrically interposed between the plurality of individual electrodes 33 and the common electrode 35. Each relay electrode 37 has two strip portions 371 and a connecting portion 373. The belt-like portion 371 is a belt-like shape extending in the sub-scanning direction y, and is formed on the heating resistor support portion 21. The opposing edge 372 of the belt-like portion 371 is along the main scanning direction x. The connecting portion 373 is a portion that connects the two belt-like portions 371 and extends along the main scanning direction x.

  The plurality of strip portions 331 and 351 are arranged in the main scanning direction x. The plurality of strip portions 371 are disposed on the heating resistor support portion 21 on the side opposite to the plurality of strip portions 331 and 351 in the sub-scanning direction y. The facing edge 352 of the adjacent strip-shaped portion 351 and the facing edge 372 of the adjacent strip-shaped portion 371 of the adjacent relay electrode 37 are opposed to each other with a gap in the sub-scanning direction y. Further, the opposing edges 372 of the remaining two strips 371 of the adjacent relay electrodes 37 and the opposing edges 332 of the two strips 331 are opposed to each other with a gap in the sub-scanning direction y. The belt-like portion 331 and the belt-like portion 371 that face each other in the sub-scanning direction y constitute a pair of belt-like portions referred to in the present invention. In addition, the belt-like portion 351 and the belt-like portion 371 facing each other in the sub-scanning direction y constitute a pair of belt-like portions referred to in the present invention. And these strip | belt-shaped parts 331,351,371 arranged in the main scanning direction x comprise the several pairs strip | belt-shaped part said by this invention.

  As shown in FIGS. 4 and 5, the electrode layer 3 is divided into a normal thick part 321, a thin part 322, and a thick part 323. The normal thickness portion 321 is constituted by the main body Au layer 301 and occupies most of the electrode layer 3. The thin portion 322 is configured by the lower layer 302, and the opposing edge 332, 352, 372 side portion of the plurality of strip-like portions 331, 351, 371 corresponds to this. The thick portion 323 is a portion where the main body Au layer 301 and the auxiliary Au layer 304 overlap each other, and the bonding portion 336, the extension portion 356, and the backbone portion 357 correspond to this. In the present embodiment, the thickness of the thick part 321 is usually about 0.6 μm, the thickness of the thin part 322 is about 0.3 μm, and the thickness of the thick part 323 is about 0.9 μm. When the auxiliary Au layer 304 is made of the material mixed with the glass frit described above, the thickness of the thick part 323 is about 1.7 μm.

  As shown in FIG. 3, the belt-like portions 331 and 371 (the same applies to the belt-like portion 351) have a portion near the tip settling with respect to the heating resistor support portion 21. This sedimentation is such that the upper surfaces of the portions of the belt-like portions 331, 351, and 371 are flush with the heating resistor support portion 21 or slightly higher.

The resistor layer 4 is a portion that generates heat when being partially energized by the electrode layer 3, and a print dot is formed by this heat generation. The resistor layer 4 is made of, for example, TaSiO ₂ or TaN and has a thickness of about 300 to 2000 mm. The resistor layer 4 is divided into a plurality of heat generating portions 41 and a plurality of electrode covering portions 42. Each heat generating part 41 is a part covering a gap sandwiched between the opposing edges 331 and 351 and the opposing edge 371 on the heating resistor support part 21, and generates heat when energized. The electrode covering portion 42 is formed so as to be interposed between the electrode layer 3 and the protective layer 5. In the present embodiment, the electrode covering portion 42 includes all the relay electrodes 37, all the strip portions 331, 351, all the bent portions 333, all the branch portions 353, and all the orthogonal portions 334, 354. , Covering. The electrode covering portion 42 is shaped to protrude about 4 μm in the width direction from the band-shaped portions 331, 351, 371 and the like.

The protective layer 5 is for protecting the electrode layer 3 and the resistor layer 4. In the present embodiment, the protective layer 5 includes a lower layer 51 and an upper layer 52 that are stacked on each other. The lower layer 51 is made of, for example, SiO ₂ and has a thickness of about 2 μm. The upper layer 52 is made of, for example, a material containing SiC and has a thickness of about 6 μm. The protective layer 5 is formed in a region extending from the vicinity of one end of the ceramic substrate 11 in the sub-scanning direction y to a portion formed on the IC electrode support portion 22 in the orthogonal portions 334 and 354. Between the protective layer 5 and the electrode layer 3, an electrode covering portion 42 of the resistor layer 4 is interposed. Thereby, the protective layer 5 and the electrode layer 3 are not in contact.

  The resin layer 6 is made of an insulating resin and has an electrode part 61 and an IC part 62. The electrode part 61 covers the skewed parts 335 and 355 and the extending part 356. The IC part 62 is formed on the basic part 357 of the common electrode 35 and supports the driving IC 7. Examples of the material of the resin layer 6 include a transparent epoxy resin.

  The drive IC 7 selectively energizes the heat generating portion 41 of the resistor layer 4 through the plurality of individual electrodes 33. The drive IC 7 is mounted on the IC portion 62 of the resin layer 6. A plurality of pads 71 are formed in two rows on the upper surface of the drive IC 7. Among these pads 71, those included in a row closer to the individual electrode 33 in the sub-scanning direction y are connected to the bonding part 336 via the wire 81. Among the plurality of pads 71, those included in a row farther from the individual electrode 33 in the sub-scanning direction y are connected to a wiring pattern formed on the wiring substrate 12 via wires 81. This wiring pattern makes the connector 83 and the drive IC 7 conductive. Further, the trunk 357 of the common electrode 35 and the wiring pattern of the wiring board 12 are connected by a wire 81.

  The sealing resin 82 is made of, for example, a black resin, and protects the drive IC 7 and the wire 81. In the present embodiment, one end of the sealing resin 82 in the sub-scanning direction y overlaps the electrode portion 61 of the resin layer 6. Further, the other end of the sealing resin 82 in the sub-scanning direction y extends to the wiring board 12.

  Next, a method for manufacturing the thermal print head 101 will be described below with reference to FIGS.

First, as shown in FIGS. 6 and 7, a ceramic substrate material 10 is prepared. The ceramic substrate material 10 is a plate-like material from which a plurality of ceramic substrates 11 can be obtained. The ceramic substrate material 10 is made of ceramic such as Al ₂ O ₃ and has a thickness of about 0.6 to 1.0 mm, for example. The glaze layer 2 is formed on the ceramic substrate material 10. The glaze layer 2 is formed by, for example, printing a paste containing glass on a portion corresponding to the heating resistor support portion 21 and the IC electrode support portion 22 and then baking the paste. In the present embodiment, the heating resistor support 21 is finished so that the dimension in the sub-scanning direction y is, for example, about 700 μm and the dimension in the thickness direction z is, for example, about 18-50 μm.

  Next, as shown in FIG. 8, glass layers 25 and 26 are formed. The glass layers 25 and 26 are formed by, for example, printing a paste containing glass on the region between the heating resistor support 21 and the IC electrode support 22 and the left region of the heating resistor support 21 in the drawing. This is done by firing. The firing temperature at this time is, for example, 790 to 800 ° C. Moreover, printing and baking are performed so that the thickness of the glass layer 25 may be about 2.0 micrometers.

  Next, as shown in FIGS. 9 and 10, a lower layer 312 is formed. The lower layer 312 is formed by, for example, printing a resinate Au paste on the entire surface of the ceramic substrate material 10 and then firing the same. The firing temperature at this time is about 790 ° C., for example. The lower layer 312 has a thickness of, for example, about 0.3 μm and an Au ratio of about 97%.

  Next, as shown in FIGS. 11 and 12, an upper layer 313 is formed. The upper layer 313 is formed by, for example, printing a resinate Au paste on the lower layer 312 with a thick film and then firing the same. In this thick film printing, as shown in FIG. 11, most of the lower layer 312 that covers the heating resistor support 21 is exposed. The firing temperature at this time is, for example, 790 ° C. The upper layer 313 has a thickness of, for example, about 0.3 μm and an Au ratio of about 97%. The main body Au layer 311 is obtained by forming the lower layer 312 and the upper layer 313.

  Next, as shown in FIG. 13, an auxiliary Au layer 314 is formed. The auxiliary Au layer 314 is formed by, for example, printing a resinate Au paste thickly so as to cover a part of the main body Au layer 311 and then baking it. The auxiliary Au layer 314 has a thickness of, for example, about 0.3 μm and an Au ratio of about 99.7%. The Au layer 30 shown in FIG. 14 is obtained by forming the main body Au layer 311 and the auxiliary Au layer 314. The auxiliary Au layer 314 may be formed by baking a paste containing granular glass and Au, and then baking the paste. The auxiliary Au layer 314 obtained in this case has a thickness of about 1.1 μm and an Au ratio of about 60%. Note that the cutting region 15 shown in this drawing is a region that is deleted when the ceramic substrate material 10 is cut in a later step to obtain a plurality of ceramic substrates 11.

  Next, the Au layer 30 is patterned. This patterning is performed by forming a mask on the Au layer 30 by a photosensitive process using a photolithographic technique and performing etching using this mask. By this patterning, as shown in FIGS. 15 to 17, an electrode layer 3 including a main body Au layer 301 composed of a lower layer 302 and an upper layer 303 and an auxiliary Au layer 304 is obtained. The electrode layer 3 has the normal thick part 321, the thin part 322, and the thick part 323 described above. The electrode layer 3 is divided into the plurality of individual electrodes 33, the plurality of relay electrodes 37, and the common electrode 35 described above.

  Next, heat treatment is performed on the ceramic substrate material 10 on which the above-described elements are formed. In this heat treatment, for example, the process of raising the temperature of the entire ceramic substrate material 10 to 830 ° C. is repeated about twice, for example. By this heat treatment, the heating resistor support 21 of the glaze layer 2 is softened. Then, as shown in FIG. 18, the plurality of belt-like portions 331, 351, 371 slightly sink with respect to the heating resistor support portion 21. In the present embodiment, the thickness of the heating resistor support 21 is relatively thin, about 18 to 50 μm. For this reason, the portions close to the tips of the plurality of band-shaped portions 331, 351, 371 sink so that the upper surface thereof is substantially flush with the upper surface of the heating resistor support portion 21, but these portions closer to the roots generate heat resistance. It hardly sinks against the body support part 21.

Next, as shown in FIGS. 19 and 20, the resistor layer 40 is formed. The resistor layer 40 is formed by sputtering using, for example, TaSiO ₂ or TaN so as to cover the entire surface of the ceramic substrate material 10, for example. The resistor layer 40 has a thickness of about 300 to 2000 μm, for example.

  Next, the resistor layer 40 is patterned. This patterning is performed by forming a mask on the resistor layer 40 by a photosensitive process using a photolithographic technique and performing etching using the mask. By this patterning, as shown in FIGS. 21 and 22, the resistor layer 4 having a plurality of heat generating portions 41 and a plurality of electrode covering portions 42 is obtained.

Next, as shown in FIG. 23, the lower layer 51 is formed. The lower layer 51 is formed by forming a mask that exposes a desired region, and then performing sputtering or CVD using SiO ₂ , for example. The lower layer 51 has a thickness of about 2.0 μm, for example. Between the lower layer 51 and the electrode layer 3, the electrode covering portion 42 of the resistor layer 4 is interposed.

  Next, as shown in FIG. 24, the upper layer 52 is formed. The upper layer 52 is formed by, for example, performing a sputtering method or a CVD method using SiC so as to overlap the lower layer 51. The upper layer 52 has a thickness of about 6.0 μm, for example. By forming the lower layer 51 and the upper layer 52, the protective layer 5 having a thickness of, for example, about 8.0 μm can be obtained.

  Next, as shown in FIG. 25, the resin layer 6 is formed. The resin layer 6 is performed, for example, by applying a transparent resin material to regions corresponding to the electrode part 61 and the IC part 62.

  Next, as shown in FIG. 26, the driving IC 7 is mounted on the IC unit 62. Next, the ceramic substrate material 10 is cut into a plurality of ceramic substrates 10 by cutting in the manner shown in FIG. Further, the ceramic substrate 11 and the wiring substrate 12 to which the connector 83 is attached are attached to the heat sink 13. Then, a plurality of wires 81 are bonded. After that, the sealing resin 82 is formed. The thermal print head 101 is completed through the above steps.

  Next, the operation of the thermal print head 101 and its manufacturing method will be described.

  According to the present embodiment, the portions near the tip of the band-shaped portions 331, 351, 371 are configured by the thin-walled portion 322. Thereby, it can suppress that the front-end edge 332,352,372 of the strip | belt-shaped parts 331,351,371 is a remarkable level | step difference. This is to prevent the resistor layer 4 from covering a significant step and is suitable for avoiding damage to the resistor layer 4.

  The base side portions of the band-shaped portions 331, 351, and 371 and the portion connected to these in the electrode layer 3 are usually constituted by a thick portion 321. Thereby, it can prevent that the electrical resistance value of the electrode layer 3 becomes unreasonably large.

  Steps are formed at the boundaries between the heating resistor support 21 and the strips 331, 351, and 371 by causing the portions near the tip of the strips 331, 351, and 371 to settle against the heating resistor support 21 of the glaze layer 2. This can be further suppressed. If the portions near the leading ends of the belt-like portions 331, 351, and 371 and the heating resistor support portion 21 are flush with each other, it is suitable for eliminating the step.

  The normal thick part 321 is constituted by the main body Au layer 301 composed of the lower layer 302 and the upper layer 303, and the thin part 322 is constituted only by the lower layer 302, thereby providing a boundary between the normal thick part 321 and the thin part 322 at a desired location. It is convenient for. Since the position of this boundary can be defined by thick film printing, a corresponding accuracy can be ensured.

  Further, according to the present embodiment, the bonding part 336 is configured by the thick part 323. The thick portion 323 is as thick as about 0.9 μm (or about 1.7 μm) while the thickness of the thick portion 321 is usually about 0.6 μm. Thereby, even if the pressure at the time of bonding the wire 81 is loaded, the possibility of being damaged by this is low. In addition, when a tensile force acts on the bonding part 336 via the wire 81, the function of weakening the stress concentration generated at the joint part between the wire 81 and the bonding part 336 is achieved. Thereby, peeling of the wire 81 and the bonding part 336 can be suppressed.

  The thick part 323 includes a main body Au layer 301 and an auxiliary Au layer 304. Since the auxiliary Au layer 304 has a higher Au ratio than the main body Au layer 301, it is suitable for increasing the bonding force with the wire 81 made of Au. In addition, when the auxiliary Au layer 304 is made of a material in which Au and glass are mixed, the surface of the auxiliary Au layer 304 tends to have a shape with a relatively large number of irregularities. Thereby, the contact area between the bonding part 336 and the wire 81 can be increased. Also by this, the joining force between the wire 81 and the bonding part 336 can be increased.

  Rhodium, vanadium, bismuth, silicon, or the like is added to the main body Au layer 301 as additive elements. These additive elements exhibit an effect of increasing the bonding force between the glaze layer 2 made of glass and the IC electrode support 22 in particular. Thereby, peeling of the bonding part 336 can be suitably prevented.

  In the present embodiment, the core portion 357 of the common electrode 35 is also configured by the thick portion 323. A driving IC 7 is mounted on the thick portion 323 via the IC portion 62 of the resin layer 6. Such a configuration is suitable for avoiding unreasonable stress concentration in the region where the driving IC 7 is mounted in the backbone 357. In addition, a wire 81 connected to the wiring board 12 is bonded to the trunk 357. The fact that the trunk portion 357 is constituted by the thick portion 323 is suitable for increasing both the bonding force with the wire 81 and the bonding force with the IC electrode support portion 22 of the glaze layer 2. Further, it is advantageous for suppressing the peeling of the trunk portion 357.

Further, according to the present embodiment, the protective layer 5 does not have a portion in direct contact with the electrode layer 3. The electrode layer 3 containing Au as a main component and the protective layer 5 formed of glass using a sputtering method have a relatively weak bonding force. On the other hand, the resistor layer 4 made of TaSiO ₂ or TaN, for example, has a relatively strong bonding force with the protective layer 5. Therefore, peeling of the protective layer 5 can be suppressed.

  Further, according to the present embodiment, the portion of the electrode layer 3 between the heating resistor support portion 21 and the IC electrode support portion 22 is formed on the glass layer 25. Since these portions are in the form of fine bands, problems such as disconnection are likely to occur if the base is rough. Since the glass layer 25 is made of glass having a softening point lower than that of the glass forming the glaze layer 2, for example, the surface thereof can be easily finished smoothly. Thereby, disconnection of the electrode layer 3 can be avoided. Further, only the direct portions 334 and 354 are positioned on the glass layer 25 in the electrode layer 3. Since the straight portions 334 and 354 are linear, there is no possibility that a biased stress that tends to occur at the bent portion, for example, is applied. Therefore, it is possible to prevent the straight portions 334 and 354 from being unduly displaced or bent.

  The plurality of orthogonal portions 334 and 354 are parallel to each other and along the sub-scanning direction y. Thereby, when arrange | positioning the same number of orthogonal parts 334 and 354, it is possible to maximize a mutual pitch. This is suitable for preventing a problem that the direct portions 334 and 354 are in contact with each other.

  In the present embodiment, the straight portions 334 and 354 are covered with the electrode covering portion 42 of the resistor layer 4. The portion of the electrode covering portion 42 has a thin band shape. Since the direct portions 334 and 354 are not easily displaced or bent, it is possible to avoid contact of the portions of the electrode covering portion 42 with each other.

  27 to 36 show another embodiment of the present invention. In these drawings, the same or similar elements as those in the above embodiment are denoted by the same reference numerals as those in the above embodiment.

  FIG. 27 shows a modification of the thermal print head 101. The thermal print head 101 shown in the figure is different from the thermal print head 101 described above in the configuration of the electrode layer 3. In this modification, the thin portion 322 is constituted by the upper layer 303 of the main body Au layer 301. The lower layer 302 is formed at a position retracted from the center of the heating resistor support 21 in the sub-scanning direction y.

  28 to 31 show a manufacturing method of a modified example of the thermal print head 101. First, after forming the glaze layer 2 and the glass layer 25 on the ceramic substrate 11, the lower layer 312 is formed. At this time, the lower layer 312 is formed so that most of the heating resistor support portion 21 is exposed. Next, an upper layer 313 is formed so as to cover almost the entire surface of the ceramic substrate material 10. Further, an auxiliary Au layer 314 is formed. Then, by patterning the Au layer 30, as shown in FIG. 30, the electrode layer 3 having the main body Au layer 301 is formed. Then, by performing a process of heating the entire ceramic substrate material 10, portions near the leading ends of the band-shaped portions 331, 351, 371 are settled with respect to the heating resistor support portion 21 as shown in FIG. Thereafter, the modified example of the thermal print head 101 is completed through the steps described with reference to FIGS.

  Even with such a modification, it is possible to prevent the electrical resistance value of the electrode layer 3 from becoming unduly large while suppressing damage to the resistor layer 4.

  32 and 33 show a thermal print head according to the second embodiment of the present invention. The thermal print head 102 of this embodiment is different from the above-described embodiment in that the configuration of the electrode layer 3 and the Ag layer 361 and the Ag protective layer 53 are provided.

  As shown in FIG. 32, the electrode layer 3 has a plurality of individual electrodes 33 and a common electrode 35. Each individual electrode 33 has a configuration similar to that of the individual electrode 33 of the thermal print head 101. The common electrode 35 includes a plurality of strip portions 351, a connecting portion 358, a detour portion 359, and a backbone portion 357. Each of the plurality of strip portions 351 extends along the sub-scanning direction y, and is arranged in the main scanning direction x. The opposing edge 352 of each strip portion 351 is opposed to the opposing edge 332 of the strip portion 331 of the individual electrode 33. The connecting portion 358 is formed near one end of the substrate 11 in the sub-scanning direction y and extends long in the main scanning direction x. The connecting part 358 connects the plurality of strip-like parts 351. The detour portion 359 is formed near the one end of the ceramic substrate 11 in the main scanning direction x, and connects the connecting portion 358 and the backbone portion 357.

  In the present embodiment, the width of the band-shaped portions 331 and 351 is about 27.3 μm, and the gap in the main scanning direction x is about 15 μm. The dimension of the bonding part 336 in the main scanning direction x is about 55 μm.

  The Ag layer 361 has a strip shape that overlaps the connecting portion 358 and the detour portion 359 of the common electrode 35, and is formed of Ag. The thickness of the Ag layer 361 is, for example, about 16 μm.

  The Ag protective layer 53 is for protecting the Ag layer 361 and has a strip shape covering all of the Ag layer 361. The Ag protective layer 53 is made of, for example, glass and has a thickness of about 4 to 10 μm.

  Next, an example of a method for manufacturing the thermal print head 102 will be described below with reference to FIGS.

  First, the glaze layer 2, the glass layers 25 and 26, and the electrode layer 3 are formed on the ceramic substrate material 10 by performing a process similar to the process described with reference to FIGS. Form. In the state shown in the figure, the band-shaped portions 331 and 351 have not yet settled with respect to the heating resistor support portion 21.

  Next, an Ag layer 361 is formed as shown in FIG. The Ag layer 361 is formed by, for example, printing a paste containing Ag on a thick film and then firing the paste. In the firing step at this time, the heating resistor support 21 is heated. As a result, the belt-like portions 331 and 351 settle against the heating resistor support portion 21.

  Next, an Ag protective layer 53 is formed. The Ag protective layer 53 is formed, for example, by printing a glass paste and firing it. In this firing step, the heating resistor support 21 is heated again. Thereby, sedimentation of the belt-like portions 331 and 351 with respect to the heating element support portion 21 is promoted. Thereafter, the thermal print head 102 is completed through steps similar to those described with reference to FIGS.

According to such an embodiment, the current that should flow through the connecting portion 358 and the detour portion 359 of the common electrode 35 also flows through the Ag layer 361. For this reason, it is possible to reduce the electrical resistance value of the common electrode 35. The Ag layer 361 is entirely covered with an Ag protective layer 53 made of glass. In the manufacturing process of the thermal print head 102, when the resistor layer 40 is formed, the Ag layer 361 is already covered with the Ag protective layer 53. For this reason, it is possible to prevent the Ag layer 361 from being altered by CF ₄ gas or O ₂ generated when the resistor layer 40 is formed using, for example, sputtering or CVD.

  Moreover, it is possible to combine the manufacturing process of the Ag layer 361 and the Ag protective layer 53 and the process of settling the portions near the leading ends of the band-shaped portions 331 and 351. Thereby, the manufacturing efficiency of the thermal print head 102 can be improved.

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

101, 102 Thermal print head 1 Support section 10 Ceramic substrate material 11 Ceramic substrate (substrate)
DESCRIPTION OF SYMBOLS 12 Wiring board 13 Heat sink 2 Glaze layer 21 Heating resistor support part 22 IC electrode support parts 25 and 26 Glass layer 3 Electrode layer 301 Main body layer 302 Lower layer 303 Upper layer 304 Auxiliary layer 30 Au layer 311 Main body Au layer 312 Lower layer 313 Upper layer 314 Auxiliary Au layer 321 Normal thick part 322 Thin part 323 Thick part 33 Individual electrode 331 Strip part 332 Opposing edge 333 Bend part 334 Straight part 335 Skew part 336 Bonding part 35 Common electrode 351 Opposite edge 353 Branch part 354 Direct part Part 355 skew part 356 extension part 357 backbone part 358 connection part 359 detour part 361 Ag layer 37 relay electrode 371 strip part 372 opposing edge 373 connection part 4 resistor layer 40 resistor layer 41 heating part 42 electrode covering part 5 protection Layer 51 Lower layer 52 Upper layer 53 Ag protective layer 6 Resin layer 61 Electrode part 62 IC part 7 IC
71 Pad 81 Wire 82 Sealing resin 83 Connector x Main scanning direction y Sub scanning direction z Thickness direction

Claims (17)

A substrate,
A glaze layer formed on the substrate and having a heating resistor support portion extending in the main scanning direction in which a cross-sectional shape perpendicular to the main scanning direction is an arc shape;
An electrode layer having a plurality of pairs of strips arranged in the main scanning direction, each comprising a pair of strips spaced apart from each other in the sub-scanning direction on the heating resistor support portion;
A resistor layer having a heat generating portion covering a gap between the pair of strip-shaped portions;
A thermal print head comprising:
The band-shaped portion has a normal thickness portion and a thin-walled portion that is thinner than the normal thickness portion and located on the gap side,
The electrode layer includes a main body Au layer composed of a lower layer and an upper layer laminated on the lower layer,
The normal thickness part is constituted by the lower layer and the upper layer,
The thermal print head, wherein the thin portion is constituted by the upper layer and is in contact with the resistor layer.   The thermal print head according to claim 1, wherein the thin portion is settled with respect to the heating resistor support portion.   The electrode layer has a plurality of relay electrodes each having two strips positioned on the same side in the sub-scanning direction among the two pairs of strips adjacent in the main scanning direction, and a connecting portion that connects the strips A plurality of individual electrodes each having one band-shaped portion of each relay electrode and the band-shaped portions constituting the pair of band-shaped portions, and each of the other band-shaped portions of the plurality of relay electrodes and the pair. The thermal print head according to claim 1, further comprising: a common electrode having a plurality of the belt-shaped portions constituting the belt-shaped portion. The common electrode has two strips adjacent to each other in the main scanning direction, and a branch portion connected to these strips.
4. The thermal print head according to claim 3, wherein the two strips of the common electrode constitute the pair of strips separately from the strips of the two relay electrodes. 5.   The electrode layer includes a plurality of individual electrodes each having one of the pair of band-shaped portions, a plurality of band-shaped portions constituting the band-shaped portions of the individual electrodes and the plurality of pairs of band-shaped portions, and the band-shaped portions. The thermal print head according to claim 1, further comprising a common electrode having a connecting portion that connects the portions. An Ag layer overlapping the connecting portion;
The thermal print head according to claim 5, further comprising an Ag protective layer that covers the Ag layer. The thermal print head according to claim 6 , wherein the Ag protective layer is made of glass. The common electrode has a base portion located at a position spaced apart from the plurality of individual electrodes with respect to the heating resistor support portion in the sub-scanning direction,
8. The thermal print head according to claim 3, wherein the basic portion supports a drive IC that selectively energizes the plurality of individual electrodes. 9.   The thermal print head according to claim 8, wherein a resin layer is interposed between the drive IC and the backbone part.   The thermal print head according to claim 1, wherein the substrate is made of ceramic. The thermal print head according to claim 10 , further comprising a metal heat sink to which the substrate is attached. Forming a glaze layer having a heating resistor support portion extending in the main scanning direction in which a cross-sectional shape perpendicular to the main scanning direction is an arc shape on the substrate;
Forming an electrode layer having a plurality of pairs of strips arranged in the main scanning direction, each comprising a pair of strips spaced apart from each other in the sub-scanning direction on the heating resistor support;
Forming a resistor layer having a heat generating portion covering a gap between the pair of strip-shaped portions;
A method of manufacturing a thermal printhead having
In the step of forming the electrode layer, in forming the belt-like portion so as to have a normal thick portion and a thin portion that is thinner than the normal thick portion and located on the gap side, While forming the main body Au layer consisting of the upper layer laminated on the lower layer, the normal thickness portion is constituted by the lower layer and the upper layer, and the thin portion is constituted by the upper layer,
In the step of forming the resistor layer, the resistor layer is formed so as to be in contact with the thin portion.   After the step of forming the electrode layer and before the step of forming the resistor layer, a step of heating the heating resistor support portion to cause the strip portion to settle with respect to the heating resistor support portion. The method for manufacturing a thermal print head according to claim 12, further comprising:   The method of manufacturing a thermal print head according to claim 13, wherein the step of forming the electrode layer includes a step of printing a paste containing Au and then baking the paste.   15. The method for manufacturing a thermal print head according to claim 13, wherein the step of forming the resistor layer uses a sputtering method or a CVD method. Forming a glaze layer having a heating resistor support portion extending in the main scanning direction in which a cross-sectional shape perpendicular to the main scanning direction is an arc shape on the substrate;
Forming an electrode layer having a plurality of pairs of strips arranged in the main scanning direction, each comprising a pair of strips spaced apart from each other in the sub-scanning direction on the heating resistor support;
Forming a resistor layer having a heat generating portion that covers a gap between each pair of strip-shaped portions;
A method of manufacturing a thermal printhead having
In the step of forming the electrode layer, the strip portion is formed to have a normal thickness portion and a thin portion that is thinner than the normal thickness portion and located on the gap side, and the electrode layer Forming a plurality of individual electrodes each having one of the pair of strips, a plurality of strips constituting the strips and the plurality of pairs of strips of these individual electrodes, and these Forming a common electrode having a connecting portion connecting the belt-like portions of
After the step of forming the electrode layer and before the step of forming the resistor layer, a step of heating the heating resistor support portion to cause the strip portion to settle with respect to the heating resistor support portion. In addition,
After the step of forming the electrode layer and before the step of forming the resistor layer, a step of forming the Ag layer by printing the Ag paste so as to overlap the connecting portion and then baking the Ag paste. ,
After the step of forming the Ag layer, before the step of forming the resistor layer, the step of forming the Ag protective layer by printing the glass paste so as to cover the Ag layer and then baking the glass paste And a method for manufacturing a thermal print head.   17. The thermal print head according to claim 16, wherein at least one of the step of firing the Ag paste and the step of firing the glass paste also serves as a step of allowing the band-shaped portion to settle against the heating resistor support portion. Manufacturing method.

Images