JP2004090254A - End face type thermal head and its manufacturing process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an end face type thermal head in which variation (distribution) in the thermal characteristics of a heat insulation layer can be suppressed and the number of thermal heads being produced per one substrate can be increased, and to provide its manufacturing process. <P>SOLUTION: At first, a plurality of thin film modules H each comprising a glaze heat insulation layer 3, a resistive film 4 including a plurality of heating resistors 4a, a common electrode 5a connected with all heating resistors 4a, a plurality of discrete electrodes 5b connected with the heating resistors 4a individually, and a protective layer 6 are formed in parallel on the surface 2a' of a head substrate. The head substrate 2 is then cut in the direction parallel with the layer direction of the thin film module H to produce individual thin film modules H and then the common electrode 5a and the plurality of discrete electrodes 5b are exposed by grinding the cutting face. Thereafter, a common conductor 7a conducting to the common electrode 5a and a plurality of discrete conductors 7b conducting to the plurality of discrete electrodes 5b, respectively, are formed by thin film forming technology on the cut faces exposing the common electrode 5a and the plurality of discrete electrodes 5b thus obtaining the end face type thermal head 1. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an end face type thermal head having a heating resistor on an end face of a substrate and a method of manufacturing the same.
[0002]
[Prior art and its problems]
Generally, a thermal head includes a plurality of heating resistors, an electrode layer for supplying current to the heating resistors, and a protective layer for protecting a part of the heating resistors and the electrode layers on a ceramic substrate having a heat insulating layer. The printing is performed by pressing the printing object through the ink ribbon while pressing the printing object around the platen roller. In such a thermal head, there is a type in which a driver IC for selectively energizing a heating resistor via an electrode layer is provided on the same substrate as the heating resistor and the electrode layer. In this type, it is necessary to ensure a sufficient distance from the heating resistor to the driver IC so that the driver IC and the protective layer covering the driver IC do not hit the platen roller during printing. The width cannot be reduced, and the number of heads that can be formed per substrate is limited.
[0003]
In recent years, it has been desired that a thermal head be capable of printing not only on paper but also on a non-bendable material such as a resin card. Therefore, recently, an end surface type thermal head capable of performing flat printing and having a plurality of heating resistors on an end surface of a substrate has been developed.
[0004]
The end-face type thermal head generally has a glaze insulating layer made of glass formed on a substrate end surface of about 7 mm or on a tapered portion provided on the substrate end surface. A plurality of heating resistors and electrode layers are formed on the glaze insulating layer. And a protective layer are sequentially laminated. The glaze insulation layer is generally formed by screen printing. For this reason, in a narrow range such as the end face of the substrate, the thickness of the glaze insulating layer tends to change depending on the alignment and tension during printing, and the reproducibility is not very good. Therefore, variation (distribution) is likely to occur in the thermal characteristics of the glaze insulating layer, and it becomes very difficult to control the heat of the plurality of heating resistors.
[0005]
[Object of the invention]
In view of the above problems, it is an object of the present invention to provide an end face type thermal head capable of suppressing variation (distribution) of thermal characteristics of a heat insulating layer and increasing the number of products per substrate, and a method of manufacturing the same. .
[0006]
Summary of the Invention
According to the present invention, if the end face head is used, the substrate width can be reduced, and if the thin film module including the heat insulating layer is formed on the substrate surface and then the substrate is cut, the heat insulating layer can be stably and easily provided on the substrate end surface. It is made by paying attention to this.
[0007]
That is, the end face type thermal head of the present invention comprises a heat insulating layer; a plurality of heating resistors; a common electrode connected to all the heating resistors; and a plurality of individually connected to each heating resistor on the end face of the head substrate. A thin film forming technique comprising a common conductor conducting to a common electrode and a plurality of individual conductors conducting to a plurality of individual electrodes, respectively, on both side surfaces substantially parallel to each other having an individual electrode; and a protective layer; Is formed as a thin film.
[0008]
It is preferable that a protective layer, an insulating protective layer covering the common conductor and the plurality of individual conductors be provided on both sides of the head substrate that are substantially parallel to each other. When the common conductor and the plurality of individual conductors are protected by the insulating protective layer, there is no possibility that the common conductor and the plurality of individual conductors may be damaged during the assembly process.
[0009]
In addition, the manufacturing method of the present invention includes a method of forming a heat insulating layer, a plurality of heating resistors, a common electrode connected to all the heating resistors, a plurality of individual electrodes individually connected to each heating resistor on the surface of the head substrate; Forming a plurality of thin film modules in parallel with each other, a step of cutting the head substrate in a direction parallel to the laminating direction of the thin film modules to cut out the individual thin film modules, and cutting when the head substrate is cut out A step of polishing the surface to expose the common electrode and the plurality of individual electrodes, and a step of exposing the common electrode and the plurality of individual electrodes to the cut surface exposing the common electrode and the plurality of individual electrodes, respectively. Forming a plurality of conductive individual conductors as a thin film by a thin film forming technique. The manufacturing method may further include a step of forming an insulating protective layer covering the common conductor, the plurality of individual conductors, and the protective layer on the cut surface of the head substrate.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a sectional view showing an end face type thermal head according to an embodiment of the present invention. An end face type thermal head (end face head) 1 of the present embodiment has a glaze heat insulating layer 3, a resistive film 4, an electrode layer 5, and a protection layer 3 having a convex curved surface 3a on an end face 2a of a head substrate 2 made of alumina or ceramic material. It has a layer 6. The resistance film 4 includes a plurality of heating resistors 4a that generate heat when energized. As is well known, the plurality of heating resistors 4a are arranged at minute intervals in a direction perpendicular to the plane of FIG. I have. The electrode layer 5 includes a common electrode 5a electrically connected to all the heating resistors 4a and a plurality of individual electrodes 5b individually electrically connected to each heating resistor 4a. The protective layer 6 functions as a wear-resistant layer and an oxidation preventing layer, and covers the common electrode 5a, the plurality of heating resistors 4a, and the plurality of individual electrodes 5b.
[0011]
On both side surfaces Ha and Hb of the end face head 1, a common conductor 7a and a plurality of individual conductors 7b respectively conducting to the common electrode 5a and the plurality of individual electrodes 5b, and from the protective layer 6 to the common conductor 7a or the plurality of individual conductors 7b. And an insulating protective layer 8 formed so as to cover. The common conductor 7a and the plurality of individual conductors 7b extend to near the rear end 2b of the head substrate 2 and are connected to the printed circuit board (PCB) 9 from the rear end 2b of the substrate. Although not shown in detail, the printed circuit board 9 is provided with a driver IC 10 for selectively energizing the plurality of heating resistors 4a and a connector portion 11 electrically connected to other circuit components. The printed board 9 and the end face head 1 are attached to a fixing plate (heat sink) 12 having a heat shielding function via an adhesive layer (not shown).
[0012]
Hereinafter, the manufacturing process of the end face head 1 will be described with reference to FIGS. 3 to 5 and FIG. 8 are cross-sectional views showing the manufacturing process of the end face head 1. 6 and 7 are side views showing the step of FIG. 5, and FIGS. 9 and 10 are side views showing the step of FIG.
[0013]
First, as shown in FIG. 3, a plurality of thin film modules H are formed in parallel on the surface 2a 'of the flat head substrate 2. In this thin-film module forming step, first, a plurality of glaze insulating layers 3 having a convex curved surface are formed at a specific position on the ceramic substrate surface 2a 'by screen printing, and then fired. Next, a resistance film 4 and an electrode layer 5 are continuously formed on each of the glaze insulating layers 3. Sputtering or vapor deposition can be used for film formation. Then, after defining the pattern shape of each electrode layer 5, the electrode layer 5 located on the heating resistor 4a of each resistance film 4 is removed by etching or the like. In the steps so far, a plurality of heating resistors 4a, a common electrode 5a electrically connected to all the heating resistors 4a, and a plurality of individual electrodes 5b electrically connected to each of the heating resistors 4a are formed. Finally, when the protective layer 6 is formed on the plurality of heating resistors 4a, the common electrode 5a, and the plurality of individual electrodes 5b, the thin film module H shown in FIG. 3 is obtained. Note that, at this time, the plurality of heating resistors 4a are arranged with a small interval in a direction perpendicular to the paper surface of FIG.
[0014]
The glaze insulating layer 3 is formed of glass having a high heat insulating property, and the resistance film 4 is made of a high melting point metal such as Ta-Si-O, TaSiONb, Ti-Si-O, Cr-Si-O, CrSiN, etc. It is formed of a cermet material. The electrode layer 5 is preferably formed as a single layer or a laminated layer using an electrode material such as Al, Au, Cu, Cr, and Mo. The protective layer 6 is formed of a material having oxidation resistance and abrasion resistance, and specifically, is formed of SiAlON, Ta ₂ O ₅ or the like. In the present embodiment, the thickness of the protective layer 6 is set to about 6 to 10 μm.
[0015]
Next, the head substrate 2 is cut along an IV-IV cutting line (a direction parallel to the laminating direction of the thin film modules H) shown in FIG. 3, and cut into individual thin film modules H as shown in FIG. Subsequently, as shown in FIG. 5, lapping (polishing) is performed on the cut surface of the cut head substrate 2 to form both side surfaces Ha and Hb substantially parallel to each other. At this time, the side end surface 5a 'of the common electrode 5a is exposed on one side surface Ha as shown in FIG. 6, and the side end surfaces 5b' of the plurality of individual electrodes 5b are exposed on the other side surface Hb as shown in FIG. Expose. In addition, on both side surfaces Ha and Hb, the respective end surfaces of the glaze heat insulating layer 3, the resistance film 4, and the protective layer 6 are also exposed.
[0016]
Then, as shown in FIG. 8, common conductors which are conductively connected to both side surfaces Ha and Hb respectively to the side end surfaces 5a 'of the common electrode 5a exposed to the side surfaces Ha and Hb and to the side end surfaces 5b' of the plurality of individual electrodes 5b. The thin film 7a and the plurality of individual conductors 7b are formed by using a photolithography technique. That is, the conductor film is entirely formed on both side surfaces Ha and Hb, and then unnecessary portions of the conductor film are removed. The common conductor 7a is formed so as to cover the entire side end face 5a 'of the common electrode 5a as shown in FIG. 9, and is further connected to the resistive film 4, the glaze insulation layer 3 and the rear end 2b of the head substrate 2 from the common electrode 5a. It is extended to the vicinity. On the other hand, the individual conductor 7b is formed for each individual electrode 5b as shown in FIG. 10, and extends from the individual electrode 5b to the vicinity of the rear end 2b of the resistive film 4, the glaze insulating layer 3, and the head substrate 2.
[0017]
Like the common electrode 5a and the plurality of individual electrodes 5b, the common conductor 7a and the plurality of individual conductors 7b can be formed as a single layer or a laminate using an electrode material such as Al, Au, Cu, Cr, or Mo. Either the common conductor 7a or the plurality of individual conductors 7b may be formed first.
[0018]
After the common conductor 7a and the plurality of individual conductors 7b are formed, the insulating protection layer 8 made of, for example, SiO ₂ , SiON, or SiN is formed on all side surfaces of the head substrate 2 including the common conductor 7a and the plurality of individual conductors 7b. The insulating protective layer 8 covers the protective layer 6, the common conductor 7a, and the individual conductor 7b. Note that a part of the common conductor 7a and the plurality of individual conductors 7b (a part on the side of the rear end portion 2b of the substrate) is connected to the printed circuit board 9 later, and thus is not covered with the insulating protective layer 8.
[0019]
Thus, the end face head 1 shown in FIG. 1 is obtained. In the end face head 1, an insulating protective layer 8 is bonded to a fixing plate 12 via an adhesive layer (not shown), and in this bonded state, a common conductor 7a and a plurality of individual conductors 7b are respectively attached to a printed circuit board 9 via a driver IC 10. As a result of conduction, it is attached to the printed circuit board 9 as shown in FIG.
[0020]
As described above, in the present embodiment, a plurality of thin film modules H having the glaze heat insulating layer 3 to the protective layer 6 are formed on the substrate surface 2a 'and then cut into individual thin film modules H, and the cut surfaces (side surfaces Ha, Hb ), A common conductor 7a and a plurality of individual conductors 7b which are electrode lead lines of the common electrode 5a and the plurality of individual electrodes 5b are formed by thin films. If the glaze insulating layer 3 is formed on the overall flat substrate surface 2a 'and the head substrate 2 is subsequently cut, the cut substrate surface 2a' becomes the substrate end surface 2a in FIG. In addition, the glaze insulating layer 3 can be provided on the substrate end face 2a by simple film thickness control, and variation (distribution) of the thermal characteristics of the glaze insulating layer 3 can be suppressed well.
[0021]
Further, in the present embodiment, the driver IC 10 is not on the substrate surface 2a '(substrate end surface 2a), and the common conductor 7a and the plurality of individual conductors 7b are formed on the side surfaces Ha and Hb, so that the space for the electrode lead wire is reduced. Since it is not necessary to provide on the substrate surface 2a '(substrate end surface 2a), the substrate width W of the end surface head 1 in the paper feeding direction can be significantly reduced. The substrate width W is generally about 7 mm according to a conventional thermal head having a heating resistor and a driver IC on the same substrate, but is about 1 to 2 mm according to the present embodiment. As a result, the number of heads produced per substrate can be greatly increased, which can contribute to cost reduction.
[0022]
Further, in the present embodiment, since the common conductor 7a and the plurality of individual conductors 7b are protected by the insulating protection layer 8, there is no possibility that the common conductor 7a and the plurality of individual conductors 7b are damaged in the heat sink assembling step. As a result, a thermal head with stable quality can be provided.
[0023]
Further, in the present embodiment, the common conductor 7a can be formed over substantially the entire side surface of the head substrate 2, so that a so-called common drop phenomenon can be suppressed.
[0024]
In this embodiment, the partial glaze type end face head 1 in which the glaze heat insulating layer 3 is partially formed on the head substrate 2 has been described. However, the present invention is applicable to other types such as full glaze, real edge, double glaze, and DOS. Is also applicable. Further, the present invention is applicable to a serial head and a line head.
[0025]
【The invention's effect】
According to the present invention, it is possible to obtain an end face type thermal head capable of suppressing variation (distribution) of the thermal characteristics of the heat insulating layer and increasing the number of products produced per substrate, and a method of manufacturing the same.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a structure of an end face type thermal head according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a state where the end face type thermal head of FIG. 1 is mounted on a printed circuit board.
FIG. 3 is a sectional view showing a manufacturing process of the end face type thermal head of FIG. 1;
FIG. 4 is a sectional view showing a step subsequent to the step shown in FIG. 3;
FIG. 5 is a sectional view showing a step subsequent to the step shown in FIG. 4;
FIG. 6 is a view taken in the direction of arrow VI in FIG. 5;
FIG. 7 is a view taken in the direction of the arrow VII in FIG. 5;
FIG. 8 is a sectional view showing a step subsequent to the step shown in FIG. 5;
FIG. 9 is a view on arrow IX of FIG. 8;
FIG. 10 is a view as viewed in the direction of the arrow X in FIG. 8;
[Explanation of symbols]
1 End-face type thermal head (end-face head)
2 Head substrate 2a End surface 2a 'Surface 2b Back end 3 Glaze heat insulating layer 4 Resistive film 4a Heating resistor 5 Electrode layer 5a Common electrode 5b Individual electrode 6 Protective layer 7a Common conductor 7b Individual conductor 8 Insulating protective layer 9 Printed circuit board 10 Driver IC
11 Connector 12 Fixing plate (heat sink)
Ha side (common conductor side)
Hb side surface (individual conductor side)

Claims (4)

A heat insulating layer; a plurality of heating resistors; a common electrode connected to all the heating resistors; a plurality of individual electrodes individually connected to each of the heating resistors; and a protective layer on the end surface of the head substrate. ,
A common conductor conducting to the common electrode and a plurality of individual conductors conducting to the plurality of individual electrodes are formed as thin films on both side surfaces substantially parallel to each other of the head substrate by a thin film forming technique. End-face type thermal head. 2. An end face type thermal head according to claim 1, further comprising an insulating protection layer covering the protection layer, the common conductor, and the plurality of individual conductors on both sides of the head substrate substantially parallel to each other. A heat insulating layer; a plurality of heating resistors; a common electrode connected to all the heating resistors; a plurality of individual electrodes individually connected to each of the heating resistors; and a protective layer on the surface of the head substrate. Forming a plurality of thin film modules in parallel, and cutting the head substrate in a direction parallel to the laminating direction of the thin film modules to cut out individual thin film modules,
A step of polishing the cut surface of the cut out of the head substrate to expose the common electrode and the plurality of individual electrodes,
A common conductor conducting to the common electrode and a plurality of individual conductors conducting to the plurality of individual electrodes, respectively, are formed as thin films on a cut surface exposing the common electrode and the plurality of individual electrodes by a thin film forming technique. The process of
A method for manufacturing an end face type thermal head, comprising: 4. The method according to claim 3, further comprising the step of forming an insulating protective layer covering the common conductor, the plurality of individual conductors, and the protective layer on a cut surface of the head substrate. Head manufacturing method.

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