JP2005238600A - Thermal head and thermal printer employing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal head T and a thermal printer capable of forming a clear print on a hard recording medium having a protrusion on the print surface. <P>SOLUTION: In a thermal head T comprising a substrate 2, a glaze layer 3 provided on the substrate 2, and a heating element array 4 provided on the glaze layer 3, the heating element array 4 is sectioned into a plurality of regions and a recess 2k is provided between the regions of sectioned heating element arrays t1, t2-tN contiguous to each other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a thermal head incorporated in a printer mechanism and a thermal printer using the same.

  2. Description of the Related Art Conventionally, a thermal head incorporated in a printer mechanism includes, for example, as shown in FIG. 5, a heat sink 11, a head substrate 12 mounted on the heat sink 11 and having a glaze layer made of glass or the like on its surface, and the head substrate 12. The heating element array 14 made of tantalum nitride or the like deposited on the end face of the head, the individual conductive layer 15a made of aluminum or the like deposited on the upper surface or the lower surface of the head substrate 12, the common conductive layer 15b, and the individual conductive layer There is known a thermal head including a driver IC 17 that selectively generates Joule heat from a heating element connected to 15a.

As the driver IC 17 is driven, a driving signal or the like is applied to the individual heating elements of the heating element array 14 via the conductive layers 15a and 15b to cause the individual heating elements to selectively generate Joule heat. Heat is conducted to the hard recording medium conveyed on the heating element of the head substrate 12, and functions as a thermal head by forming a predetermined print on the hard recording medium.
JP-A-5-208514

  By the way, in such a thermal head, the end surface of the head substrate 12 is formed substantially flat along the longitudinal direction. A heating element array 14 is continuously formed on the end face in the longitudinal direction.

  Using a thermal printer equipped with such a thermal head, for example, an IC chip is embedded, and the upper part of the IC chip protrudes from the upper surface of the card, so When a print is to be formed on a hard recording medium such as a card having a convex portion formed on the surface by embossing, the convex portion protruding from the printing screen comes into contact with the heating element array 14, and the convexity of the printing screen The periphery of the portion cannot sufficiently contact the heating element array due to the convex portion, and as a result, the print density is reduced only around the convex portion, and in some cases, the print is not formed.

  The present invention has been devised in view of the above-described drawbacks, and an object of the present invention is to provide a thermal head T and a thermal printer capable of forming a clear print on a hard recording medium having a convex portion on a print screen. There is.

  The thermal head of the present invention is a thermal head having a substrate, a glaze layer provided on the substrate, and a heating element row provided on the glaze layer, and the heating element row is divided into a plurality of regions. In addition, a recess is provided between the divided adjacent heating element array regions.

  The thermal head of the present invention is characterized in that the heating element array and the recess are located on an end surface of the substrate.

  Furthermore, the thermal head of the present invention is characterized in that a part of the glaze layer is extended to the inner wall surface of the recess to cover a corner between the inner wall surface of the recess and the upper surface of the substrate. Is.

  A thermal printer of the present invention includes the above-described thermal head and a transport unit that transports a hard recording medium having a convex portion on a printing screen, and when the hard recording medium is transported, the convex portion of the hard recording medium is The thermal head is arranged so as to be positioned in the recess of the thermal head.

  According to the present invention, in a thermal head having a substrate, a glaze layer provided on the substrate, and a heating element row provided on the glaze layer, the heating element row is divided into a plurality of regions. Since the concave portions are provided between the divided adjacent heating element array regions, when an image is formed on a hard recording medium such as a card having a convex portion formed on the surface by embossing or the like, for example, When the convex portion is located in the concave portion of the head substrate, it can be brought into sliding contact with the heating element array even around the convex portion. As a result, it is possible to prevent the print density from being reduced only around the convex portion and to prevent the print from being formed, and a desired print can be formed.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a perspective view of a thermal head T according to an embodiment of the present invention. The thermal head T is mainly mounted on a heat sink 1 and a glaze layer made of glass or the like on the heat sink 1. 3, a heating element array 4 made of tantalum nitride or the like deposited on the end surface of the head substrate 2, and an individual conductive layer made of aluminum or the like deposited on each of the upper and lower surfaces of the head substrate 2. 5a, a common conductive layer 5b, and a driver IC that selectively generates Joule heat from the heating elements connected to the individual conductive layer 5a.

  The heat sink 1 constituting the thermal head T of the present invention is formed in a rectangular shape with a metal material having good heat conductivity such as aluminum, and the head substrate 2 is placed on the upper surface of the heat sink 1 via a double-sided tape or the like. . The heat radiating plate 1 supports the head substrate 2 on its upper surface, absorbs a part of heat from a heat generating element to be described later when the thermal head T is driven, and dissipates this in the atmosphere to thereby dissipate the head substrate 2. This is to effectively prevent the temperature of the liquid from becoming excessively high. For example, in the case where the heat radiating plate 1 is made of aluminum, the heat radiating plate 1 is manufactured by processing an aluminum ingot (lumb) into a predetermined shape using a conventionally known metal processing method.

  Further, the head substrate 2 is placed on the upper surface of the heat radiating plate 1 so as to overlap the heat radiating plate 1.

  Such a head substrate 2 is formed in a rectangular shape by various materials such as an insulating material such as alumina ceramics, or single crystal silicon having an oxide film deposited on the surface thereof.

  Further, the head substrate 2 is arranged so as to provide an overhanging portion 2 h by projecting one end surface along the longitudinal direction of the head substrate 2 from one end surface along the longitudinal direction of the radiator plate 1.

  The head substrate 2 has a protruding base 2h at its end surface, and supports a belt-like glaze layer 3, a heating element array 4, and a protective film 6, and a support mother that supports the individual conductive layer 5a and the common conductive layer 5b on the upper and lower surfaces, respectively. Functions as a material.

  The projecting portion 2h is formed so that its cross-sectional shape forms an R surface, and the heating element array 4 is formed on the top.

  When such a head substrate 2 is made of alumina ceramics, for example, an appropriate organic solvent or solvent is added to and mixed with ceramic raw material powders such as alumina, silica, and magnesia to form a slurry, and this is formed into a conventionally known doctor. A ceramic green sheet is obtained by adopting a blade method, a calender roll method, or the like, and thereafter, the green sheet is punched into a predetermined shape and then fired at a high temperature (about 1600 ° C.).

  Further, a groove-like recess 2k is provided in the projecting portion 2h of the head substrate 2 along the transport direction of the hard recording medium K. The end surface of the protruding portion 2h of the head substrate 2 is divided into N regions k1, k2,... KN (N is a natural number of 2 or more) by the recess 2k.

  This is because, for example, an IC chip is embedded, and the upper part of the IC chip protrudes from the upper surface of the card, so that the hard recording medium K has a convex portion Kt on the printing screen, or the convex portion Kt by embossing on the surface. In some cases, a print is formed on a hard recording medium K such as a card on which is formed. In such a case, the concave portions 2k are provided corresponding to the number of the convex portions Kt so that the convex portions Kt protruding from the marking screen and the head substrate 2 do not collide. Therefore, when the hard recording medium K is conveyed, the convex portion Kt passes through the concave portion 2k.

  The size of the concave portion 2k is formed corresponding to the size of the convex portion Kt of the hard recording medium. For example, an embossed character or the like embossed on the surface of a card or the like has a width corresponding to the main scanning direction at the time of printing of about 3 mm to 5 mm and a height of about 0.1 mm to 1.0 mm. The width and depth of the concave portion 2k are slightly larger than that. Specifically, the width in the main scanning direction is about 1.0 mm larger than the width of the convex portion Kt, and the depth to the bottom surface of the concave portion 2k is the convex portion. What is necessary is just to make about 1.0 mm deeper than the height of Kt.

  The recess 2k may be formed simultaneously with the punching process of the ceramic green sheet, or may be formed by cutting with a laser, a water jet or the like after the high temperature firing and before the deposition of the glaze layer. The former can form the recess 2k without increasing a new process, while the latter can form the recess 2k with higher accuracy than the former.

  For example, when it is desired to form a print in the immediate vicinity of the convex portion Kt of the hard recording medium K, it is necessary to form the heating element array 4 to the immediate vicinity of the concave portion 2k of the head substrate 2, so the concave portion 2k of the thermal head is In addition, it is desirable to accurately form the concave portion 2k having the smallest possible size that can accommodate the convex portion Kt of the hard recording medium. In such a case, cutting with a laser, a water jet, or the like is desirable.

  Further, the protruding portion 2h of the head substrate 2 has a projecting width of about 1.5 mm to 2.0 mm. If the amount of protrusion is smaller than 1.5 mm, the bottom surface of the concave portion 2k is positioned on the inner side of the thermal head with respect to the end surface of the heat radiating plate 1, and the convex portion Kt of the hard recording medium is formed during printing. The end face of the heat radiating plate 1 may collide, and sufficient contact between the heating element array 4 and the hard recording medium may not be obtained. If it is larger than 2.0 mm, when a large frictional force accompanying sliding of the hard recording medium is applied to the overhanging portion 2h, cracks enter from the corner portion formed by the inner wall surface and the bottom surface of the recess 2k, The possibility that the head substrate 2 breaks cannot be denied.

  In order to reduce the size of the thermal head T in order to reduce the size of the thermal head T, the end face of the heat radiating plate 1 that is located on the outer side of the thermal head T with respect to the bottom surface of the recess 2k is cut away. In addition, a recess may be provided. Thereby, it is possible to prevent the bottom surface of the concave portion of the heat dissipation plate from being located on the outer side of the thermal head T, that is, the hard recording medium side than the bottom surface of the concave portion of the head substrate 2.

  Then, on the surface of the protruding portion 2h of the head substrate 2, strip-shaped glaze layers g1, g2,... GN are formed for the respective regions k1, k2,. .

  This glaze layer 3 (indicated as 3 when indicating a general glaze layer, and expressed as g1, g2,..., GN when referring to a glaze layer for each region) is the heat generated by the heating element array 4. It stores heat inside and maintains the thermal response of the thermal head.

As the material of the glaze layer 3, glass is mainly employed. For example, silicon oxide (SiO ₂ ) is 40% by mass to 60% by mass, aluminum oxide (Al ₂ O ₃ ) is 5% by mass to 10% by mass, and oxidation is performed. A glass containing 10% by mass to 15% by mass of calcium (CaO) and 20% by mass to 30% by mass of barium oxide (BaO) is preferably used.

  Further, as shown in FIG. 3, the glaze layer 3 covers each of the regions k1, k2,... KN of the overhang portion 2h, and the glaze layers g1, g2 of the regions k1, k2,. ,... GN in the longitudinal direction extends to the inner wall surface of the recess 2k of the projecting portion 2h of the head substrate 2, and covers the corner between the inner wall surface of the recess 2k and the upper surface of the projecting portion 2h. doing.

  The above glaze layer 3 is a glass paste obtained by adding / mixing an appropriate organic solvent, organic binder, etc. to the glass powder and printing / coating it in a predetermined area on the upper surface of the substrate by a conventionally known screen printing method, This is formed by adopting a conventionally known photolithography technique and etching technique to be processed into a predetermined shape, and then heated at a high temperature of 850 ° C. to 950 ° C. for a predetermined time.

  And it is known that the glaze layer 3 formed in this way generally rises higher in the longitudinal direction than in the center. This is thought to be due to the following mechanism.

  That is, when the glass paste is fired, solidification starts from the outer surface of the glass paste. Since the end portion in the longitudinal direction has a larger surface area than the central portion, there are more regions where solidification proceeds quickly. Then, the glass paste is solidified to become glass, and the glass paste before solidification existing around the glass paste is attracted to the solidified glass by the surface tension of the glass. More glass paste is attracted to the end portion where the solidification progresses more quickly than the central portion of the glaze layer 3, and this is raised.

  In the present invention, when the glaze layers 3 are fired, even if the end portions of the glaze layers g1, g2,... GN in the longitudinal direction on the concave portion 2k side rise higher than the center portion, the end portions Is located inside the recess 2k, so that the end of the glaze layer 3 does not protrude toward the hard recording medium K side from the center during printing, and the hard recording medium K and the heating element are printed during printing. The sliding contact with can be made well.

  In addition, on each of the above-described belt-like glaze layers g1, g2,... GN, each of the glaze layers g1, g2,. When shown, it is written as 4, and when referring to a heating element row for each region, it is written as t1, t2,.

  This heating element array 4 is linearly deposited and arranged at a density of 300 dpi (dot per inch) or 600 dpi, and each is an electric resistance material of TaSiO, TaSiNO, TiSiO, TiSiCO, or NbSiO. It consists of a resistor layer consisting of

  It should be noted that the formation density may be changed for each of the heating element rows t1, t2,... TN in the regions g1, g2,. For example, when it is desired to print a photograph on the printing screen of the hard recording medium corresponding to the heating element row t1 and fine character information on the printing screen of the hard recording medium corresponding to the heating element row t2, the formation density of the heating element row t1 is set. The formation density of the heater element row t2 may be set to 600 dpi.

  On the other hand, a conductive layer 5 made of a metal material such as aluminum or copper connected to both ends of the heating element rows 4 extends from one end side of the heating element rows 4 to the upper surface of the head substrate 2. An individual conductive layer 5 a that connects the driver IC 5, and a common conductive layer 5 b that extends from the other end of the heating element row 4 to the lower surface of the head substrate 2 and is connected to the plurality of heating element rows 4 in common. The individual conductive layer 5a and the common conductive layer 5b function as a power supply wiring for supplying power from the outside to the heating element array 4.

  The heating element array 4 and the conductive layers 5a and 5b are manufactured by employing a conventionally well-known thin film forming technique, for example, sputtering, photolithography technique, etching technique or the like. Specifically, first, a laminated body composed of a heating element and a metal layer is formed by sequentially laminating a resistance material such as TaSiO and a metal material such as aluminum on the substrate 1 by means of conventionally known sputtering, and this is formed as a conventionally known material. The heat generating element array 4 and the conductive layers 5a and 5b are formed by microfabrication using a photolithography technique and an etching technique.

  On the other hand, a protective film 6 is deposited on the heating element row 4 and the conductive layers 5a and 5b, and the heating element row 4 and the conductive layers 5a and 5b are covered with the protective film 6.

  The protective film 6 is for protecting the heating element array 4 and the conductive layers 5a and 5b from corrosion due to contact with moisture or the like contained in the atmosphere and wear due to sliding contact with the hard recording medium K. Or SiN-based, SiO-based, SiON-based inorganic materials, glass, or the like to form a thickness of 3 μm to 10 μm.

  Furthermore, the protective film 6 also covers the inner wall surface of the recess 2k described above. As described above, the inner wall surface is also covered with a part of the glaze layer 3, and a protective film is deposited on the glaze layer 3 in a portion where the glaze layer 3 exists. Accordingly, when an image is to be formed on the hard recording medium K having the convex portion Kt, the shape of the inner wall surface of the concave portion 2k after the protective film 6 is deposited is the convexity of the hard recording medium K. In order to prevent the portion Kt from colliding with the head substrate 2 or the like, it is necessary to have a shape through which the convex portion Kt can pass. That is, the surface of the protective layer 6 on the bottom surface of the recess 2k is located on the inner side of the thermal head T (the side away from the hard recording medium) than the surface of the protective layer 6 on the heating element array 4.

  The protective film 6 is formed by a conventionally known thin film forming technique (sputtering method, vapor deposition method, CVD method, etc.) or a thick film forming technique (screen printing method, dispenser method, etc.).

  For example, when the SiC-based protective film 6 is formed by the sputtering method of the thin film formation technique, a target material made of a sintered body in which carbon (C) and silicon (Si) are mixed in the chamber of the sputtering apparatus; The heating element array 4 and the head substrate 2 on which the conductive layers 5a and 5b are formed are respectively disposed. Next, while introducing argon gas into the chamber, a predetermined gap is provided between the target material and the head substrate 2. A part of the target material is deposited on the head substrate 2 by applying power and sputtering the constituent material of the target material with argon.

  When the protective film 6 made of glass is formed by the screen printing method of the thick film forming technology, the glass powder is mixed with an organic solvent / solvent to form a paste, and this is applied to the substrate by the screen printing method. It is formed by applying and baking the applied glass paste at a temperature of, for example, 400 ° C. to 500 ° C. for about 30 minutes.

  The driver IC 7 disposed on the upper surface of the head substrate 2 and controlling the energization of the heating element array 4 has a high density of shift registers, latches, switching elements, input terminals, output terminals, etc. on one main surface of the silicon substrate. The integrated circuit is integrated and is electrically connected to the heating element array 4 via the conductive layers 5a and 5b.

  The driver IC 7 inputs external image data to the shift register via the input terminal while synchronizing with the clock signal, stores the input image data in the latch at the timing of the latch signal, and the strobe signal is switched. While being input to the element, energization to the heating element array 4 is performed based on the image data in the latch.

  Such a driver IC 7 is manufactured by adopting a conventionally well-known semiconductor manufacturing technique, and the obtained driver IC 7 is input / output by a conventionally well-known wire bonding method, tape auto bonding method, or face down bonding method. It is mounted on the upper surface of the head substrate 2 by electrically connecting the terminal and the individual conductive layer 5a.

  In the present invention, the driver IC 7 is made independent for each of the regions t1, t2,. That is, a separate driver IC 7 is provided for each of the regions t1, t2,..., TN so that a print can be formed independently in each region. This makes it easy to control the image data even when the formation density of the heating element rows t1, t2,... TN is changed for each region t1, t2,.

  Further, such a driver IC 7 is sealed with a sealing resin 8 made of a resin material such as a thermosetting epoxy resin.

  The sealing resin 8 is formed such that its cross-sectional shape forms a mountain shape, and functions to protect the conductive layers 5a and 5b and the driver IC 7 from corrosion caused by moisture contained in the atmosphere.

  For the sealing resin 8, a predetermined liquid precursor made of, for example, an epoxy resin is applied so as to cover the driver IC 7 on the head substrate 2, and this is heated and polymerized at a high temperature (130 ° C. to 150 ° C.). It is formed by letting.

  Thus, the thermal head T of the present embodiment is accompanied by driving the driver IC 7 between the individual conductive layer 5a and the common conductive layer 5b while sliding the hard recording medium K on the heating element array 4 formed on the end surface of the head substrate 2. Power supply is applied to each heating element in response to a printing signal to individually generate Joule heat, and the generated heat is conducted to the hard recording medium K to form a print on the hard recording medium K. It functions as a thermal head T.

  At this time, even if the hard recording medium K is a card having a convex portion Kt formed on the surface by embossing or the like, since the convex portion Kt is located on the concave portion 2k of the head substrate 2, The seal screen can be brought into sliding contact with the heating element array 4 even around the convex portion Kt. As a result, it is possible to prevent the print density from being reduced only around the convex portion Kt and to prevent the print from being formed, and a desired print can be formed.

  Next, a thermal printer in which the above-described thermal head T is incorporated will be described.

  In the thermal printer of the present invention, as shown in FIG. 4, a platen roller R1 that presses the hard recording medium K and the ink ribbon I against the thermal head T is disposed on the above-described thermal head T, and the hard recording medium K and ink. A transport roller R2 for transporting the ribbon I is disposed, and these are controlled by a driving unit.

  A platen roller R1 that presses the hard recording medium K and the ink ribbon I against the heating element array 4 is preferably 8 mm to 50 mm in diameter, and butadiene rubber or the like is placed on the outer periphery of a shaft core made of metal such as SUS. It is a cylindrical member wound to a thickness of about 3 mm to 15 mm, and is rotatably supported on the heating element array 4 of the thermal head T.

  The platen roller R1 presses the hard recording medium K and the ink ribbon I against the thermal head T, conducts heat from the heating element array 4 to the ink ribbon I, and this heat causes the ink on the ink ribbon I to be hard-recorded. While transferring to the medium K, the hard recording medium is conveyed in a direction orthogonal to the arrangement of the heating element rows 4.

  For example, an IC chip is embedded and the upper part of the IC chip protrudes from the upper surface of the card, so that a print is made on a hard recording medium K such as a card having a projection Kt on the printing screen using this thermal printer. For the formation, when the card is conveyed onto the heating element array 4 by the platen roller R1, the convex portion Kt of the card may be disposed on the concave portion 2k of the head substrate 2 described above. .

  Thereby, the stamp screen can be slidably brought into contact with the heating element row 4 even around the convex portion Kt. As a result, it is possible to prevent the print density from being reduced only around the convex portion Kt and to prevent the print from being formed, and a desired print can be formed.

  The ink ribbon I is individually provided for each heating element row t1, t2,... TN of each region k1, k2,. If the ink ribbon I is not positioned on the portion Kt, the occurrence of wrinkles due to the pressing of the convex portion Kt against the ink ribbon I can be prevented.

  The present invention is not limited to the above-described embodiments, and various changes and improvements can be made without departing from the scope of the present invention.

  For example, in the above-described embodiment, in order to form the recess 2k in the projecting portion 2h of the head substrate 2, the recess 2k is formed after the head substrate 2 is baked and before the glaze layer 3 is deposited. After all of the glaze layer, the heating element array, the conductive layer, the protective film, and the like are formed on the substrate, the recesses may be provided by cutting them with a laser or the like. In this way, it is possible to form a recess having the desired size more accurately than when the recess is formed before the glaze layer is deposited after firing the head substrate.

  When it is desired to form a print on the top surface of the convex portion of the hard recording medium, a heating element array may be formed on the bottom surface of the concave portion.

  Further, in the present invention, the concave portion through which the convex portion of the hard recording medium passes is formed by cutting out the head substrate, but instead of this, for example, by making the glaze layer for each region thicker, the glaze is formed. A concave portion by a layer may be formed, and the convex portion of the hard recording medium may be passed through the concave portion.

It is a perspective view of the thermal head concerning one embodiment of the present invention. FIG. 2 is a cross-sectional view taken along a plane orthogonal to a main scanning direction of a heating element array of the thermal head of FIG. 1. FIG. 2 is an enlarged cross-sectional view of a main part taken along a plane parallel to the top surface of the head substrate of the thermal head of FIG. 1. 1 is a schematic cross-sectional view of a thermal printer according to an embodiment of the present invention. It is a perspective view of the conventional thermal head.

Explanation of symbols

T ... Thermal head 1 ... Heat sink 2 ... Head substrate 2h ... Overhang 2k ... Recess 3 ... Glaze layer 4 ... Heating element array t1-tN ... Overhang Each heating element array 5 provided on each region 2h ... conductive layer 5a ... individual conductive layer 5b ... common conductive layer 6 ... protective film 7 ... driver IC
8 ... Sealing resin R1 ... Platen roller R2 ... Conveying roller K ... Hard recording medium Kt ... Convex part I of hard recording medium ... Ink ribbon

Claims (4)

In a thermal head having a substrate, a glaze layer provided on the substrate, and a heating element array provided on the glaze layer,
A thermal head characterized in that the heating element rows are divided into a plurality of regions, and a concave portion is provided between the divided regions of adjacent heating element rows. The thermal head according to claim 1, wherein the heating element array and the recess are located on an end surface of the substrate. 3. A part of the glaze layer is extended to the inner wall surface of the recess to cover a corner between the inner wall surface of the recess and the upper surface of the substrate. The thermal head described. A thermal head according to any one of claims 1 to 3, and a transport unit that transports a hard recording medium having a convex portion on a printing screen, and when the hard recording medium is transported, A thermal printer, wherein a convex portion is disposed in a concave portion of the thermal head.

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