JP2001105641A - Thermal print head and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal print head capable of maintaining printing in good condition and effectively preventing a thin film of a protection layer from being peeled. SOLUTION: There is disclosed a thermal print head wherein heat accumulating glaze layers 20A, 20B are formed on a printing portion P on a surface of a substrate 10 and a predetermined plane region S isolated therewith, respectively, a heating resistor 30 and an electrode layer 40 are formed on the heat accumulating glaze layers 20A, 20B as conductors, and a protection layer 50 is formed on the surface of the substrate 10 so as to cover the heat accumulating glaze layers 20A, 20B and the conductors 30, 40. The heat accumulating glaze layers 20A, 20B on the printing portion P and plane region S are formed to be continuously integrated with a glaze lower position layer 20C which is lower than the highest sections 20Aa, 20Ba of the heat accumulating glaze layers 20A, 20B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal print head for printing on, for example, a card or cardboard,
And its manufacturing method.

[0002]

2. Description of the Related Art Thermal print heads for thermal printers are roughly classified into a thick film type and a thin film type.
FIG. 7 shows an example of a thin film type thermal print head. The thermal print head of the thin film type shown in FIG. 7 is divided into a printing area P on the surface of the substrate 100 and a plane area S which is separated from the area P and on which a driving IC (not shown) is mounted. 200A, 20
OB is formed by bulging by a printing film forming method or the like.
On these thermal storage glaze layers 200A, 200B,
The heating resistor 300 as a conductor and the electrode layer 400 are formed by the sputtering method, and the protective layer 500 is formed by the sputtering method so as to cover the heat storage glaze layers 200A and 200B and the electrode layer 400 from the surface of the substrate 100. Have been.

[0003] In particular, the thermal storage glaze layer 200A in the printing area P has a thermal storage glaze layer 200 in the other flat area S in order to improve the contact surface pressure with respect to the printing object.
Apart from OB, it is formed as a partial glaze layer bulging in a ridge shape. On the other hand, the outermost protective layer 500
Is formed as a thin film by a sputtering method, and the vicinity of the printing portion P of the protective layer 500 is partially bulged in accordance with the shape of the heat storage glaze layer 200A. Note that the thickness of the heat storage glaze layers 200A and 200B is at most about several tens of μm.

[0004]

Here, the heat storage glaze layers 200A and 200B are partially formed on the surface of the flat substrate 100 by a printing film forming method or the like, and then integrated with the substrate 100 through firing and cooling. ing. However, when firing the heat storage glaze layers 200A and 200B, 100
When exposed to a high temperature of 0 ° C. or more, and cooled from such a high temperature state, the cooling effect depending on the thickness causes a difference between the thickest portions 200Aa and 200Ba as shown in FIG.
In this case, fine crystals were deposited on the skirt portion gradually becoming thinner as indicated by the symbol X. Hem part X with such crystals
When the protective layer 500 and the like are formed thereon, the surface of the protective layer 500 in the vicinity thereof becomes uneven and rough,
There is a problem that, for example, the printing state of a card, cardboard, or the like that slides while closely contacting the protective layer 500 at the printing portion P is adversely affected.

On the other hand, for example, the protective layer 500 at the printing portion P is formed in a ridge shape by sputtering according to the shape of the heat storage glaze layer 200A below it as described above. That is, the thermal storage glaze layers 200A, 2
From the skirt portion X of 00B to the surface of the substrate 100 serving as a base, as shown in FIG. 7, the state is rapidly changed from an inclined state to a horizontal plane, and when the protective layer 500 is formed into a thin film by a sputtering method, A so-called step coverage growth in which the growth is performed in a direction perpendicular to each base, that is, a tear portion 500A is formed near the foot X of the base.
Was generated separately from the crystal. Such a rupture portion 500A causes the protective layer 500 to peel off the film. In particular, in the printing portion P where the print target slides, the close contact force from the print target acts on the protective layer 500. Therefore, there was a problem that the protective layer 500 was easily peeled from the rupture part 500A as a starting point.

Accordingly, the present invention has been conceived in view of the above-mentioned circumstances, and it is possible to maintain a good printing state on an object to be printed, and to obtain a film from a rupture portion due to so-called step coverage growth. It is an object of the present invention to provide a thermal print head capable of preventing peeling and a method for manufacturing the same.

[0007]

DISCLOSURE OF THE INVENTION In order to solve the above problems, the present invention employs the following technical means.

That is, in the thermal print head provided by the first aspect of the present invention, a thermal storage glaze layer is bulged and formed in a printing area on a surface of a substrate and a predetermined plane area separated from the area. A thermal printhead obtained by forming a conductor on the glaze layer, and further forming a protective layer on the surface of the substrate so as to cover the heat storage glaze layer and the conductor, wherein The thermal storage glaze layer,
It is characterized in that it is integrally connected to the lower glaze layer lower than the uppermost portion thereof.

It is to be noted that a driving chip electrically connected to the conductor may be mounted on the plane area. According to such a configuration, it is possible to selectively heat the conductors in the printing area by the drive chips and to drive the heat generation, thereby providing a thermal print head integrally provided with such drive chips.

A method for manufacturing a thermal print head according to a second aspect of the present invention includes forming a thermal storage glaze layer in a printed area on a surface of a substrate and a predetermined plane area separated from the printed area by bulging the thermal storage glaze layer. A method for manufacturing a thermal print head obtained by forming a conductor on these thermal storage glaze layers and further forming a protective layer on the surface of the substrate to cover the thermal storage glaze layer and the conductor, When forming the thermal storage glaze layer in the printing region and the planar region, the glaze lower layer lower than the uppermost portion thereof is integrally formed so as to be continuous with each other.

In the method of manufacturing a thermal print head according to the first aspect or the thermal print head according to the second aspect, in which the above technical means have been taken, not only the printing portion and the predetermined plane area on the surface of the substrate, but also Is integrated by a lower glaze layer having a certain thickness so that the heat storage glaze layer in the printing region and the plane region is continuous. In short, the thermal storage glaze layer having a predetermined thickness is present in the print portion and the flat region, while the glaze lower layer having a small thickness is continuous between the print portion and the flat region. It is in a state of having done.

Therefore, according to the method for manufacturing a thermal print head according to the first aspect or the thermal print head according to the second aspect of the present invention, the heat storage glaze layer in the printing portion and the flat region is fired at a high temperature. Later, when forming a bulge by cooling, etc.,
Since the lower glaze layer with a certain thickness is formed integrally with the heat storage glaze layer, it is necessary to use at least the thickness of the lower glaze layer to prevent crystal precipitation occurring in the glaze layer due to differences in thickness. As a result, the protective layer formed on the heat storage glaze layer can be used as a smooth surface to maintain a good printing state on the printing target.
Further, since the thermal storage glaze layer extending from the printing portion to the plane area is in a state of being smoothly connected via the glaze lower layer, for example, when the protective layer is formed as a thin film by a sputtering method or the like, the thermal storage glaze layer and the glaze which are the bases are formed. Even for the lower layer, the protective layer can be uniformly deposited and grown without causing breakage due to so-called step coverage growth, and the peeling of the protective layer caused by such breakage due to the step coverage growth is prevented. can do.

In a preferred embodiment of the thermal print head according to the first aspect, the lower glaze layer is formed so as to be gently and continuously integrated from the uppermost portion of the thermal storage glaze layer in a skirt shape. It can be.

In a preferred embodiment of the method for manufacturing a thermal print head according to the second aspect, the lower glaze layer is gently and continuously integrated from the uppermost portion of the thermal storage glaze layer to form a skirt. A configuration may be formed.

According to such a configuration, the heat storage glaze layer extending from the printing portion to the plane region is in a state of being smoothly connected from the uppermost portion thereof through a flared lower glaze layer which is gradually and continuously integrated. Therefore, when depositing and growing the protective layer using the thermal storage glaze layer and the lower glaze layer as a base, the step coverage growth can be more effectively prevented, and the peeling of the protective layer can be reliably prevented. it can.

Further, as another preferred embodiment of the method for manufacturing a thermal print head according to the second aspect, the thermal storage glaze layer and the glaze lower layer include:
After the glaze layer is formed over the entire surface of the substrate, a predetermined thickness may be removed from portions other than the printing portion and the flat region by etching, and the structure may be further baked.

According to such a configuration, the heat storage glaze layer and the lower glaze layer can be formed continuously and integrally, and the entire surface of the substrate is formed by the glaze layer having a certain thickness and a smooth surface. Because it is covered, crystal precipitation and step coverage growth are completely eliminated over the entire surface of the substrate, and the printing state on the printing object can be kept good over the entire surface, and the film peeling of the protective layer can be effectively prevented. Can be prevented.

Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of a thermal print head according to the present invention, and FIG. 2 is a plan view showing a portion indicated by an arrow P in FIG. In FIG. 2, the protective layer denoted by reference numeral 50 in FIG. 1 is omitted. Further, in each of the drawings, the entire outer shape of the thermal print head is not shown. However, the thermal print head has a vertically long outer shape in accordance with a printing target such as a card or cardboard and has a longitudinal direction (FIG. 1). (The left and right directions in FIG. 2).

As shown in FIGS. 1 and 2, the thermal printhead according to the present invention has a portion indicated by an arrow P as a printing portion, and a driving IC (not shown) in a plane area S which is somewhat away from the printing portion P. Equipped with,
It belongs to the so-called thin film type. The thermal print head includes a substrate 10, a thermal storage glaze layer 20.
A, 20B, a lower glaze layer 20C, a heating resistor 30 as a conductor, an electrode layer 40 also as a conductor, a protective layer 50, and the like. When using such a thermal printhead for printing,
As is well shown in FIG.
Are pressed against each other, and printing is performed such that the printing target M is inserted between them.

The thermal print head according to this embodiment will be described in detail. For example, the entire surface of a substrate 10 made of alumina ceramic or the like is shown in FIG.
As shown in FIG. 2, thermal storage glaze layers 20A and 20B having uppermost portions 20Aa and 20Ba are respectively formed by being divided into a print region P and a plane region S, and a bulge is formed between the print region P and the plane region S. Also, the top 20
The lower glaze layer 20C lower than Aa and 20Ba is continuously formed integrally with the heat storage glaze layers 20A and 20B. The heat storage glaze layer 20A at the printing portion P
Is formed to be partially bulged separately from the plane region S in order to improve the contact surface pressure with respect to the printing object M. As shown in FIG. 1, the lower glaze layer 20 </ b> C is formed gradually and continuously from the uppermost portions 20 </ b> Aa, 20 </ b> Ba of the thermal storage glaze layers 20 </ b> A, 20 </ b> B from the printing portion P to the planar region S in a skirt shape. I have. The method of forming the heat storage glaze layers 20A and 20B and the lower glaze layer 20C will be described later in a manufacturing method.

On the surfaces of the heat storage glaze layers 20A and 20B and the lower glaze layer 20C, a large number of linear heating resistors 30 are formed at equal pitch intervals T. This pitch interval T determines the printing resolution. Further, a large number of linear electrode layers 40 are formed so as to overlap on the respective heating resistors 30, and these electrode layers 40 are electrically connected to the driving IC mounted on the plane area S. . On the other hand, a small hole 40a reaching the lower heating resistor 30 is formed in a predetermined portion of the electrode layer 40 in the printing portion P.
That is, when the electrode layer 40 is selectively energized by the drive IC, the heating resistor 30 in contact with the energized electrode layer 40 generates heat. The heat generated from the heating resistor 30 is insulated by the heat storage glaze layers 20A and 20B and the like, while the electrode layer 4 is insulated.
0 to the external print object M through the small hole 40a,
As a result, the print target M is printed.

Further, over the entire surface of the substrate 10, a protective layer 50 is formed so as to cover the heat storage glaze layers 20A and 20B and the lower glaze layer 20C, the heating resistor 30 as a conductor, and the electrode layer 40. . The protection layer 50 is provided so that the printing target M does not directly touch the electrode layer 40 at the printing portion P or the like. The printing target M is slidable while being in close contact with the protection layer 50. ing.

Next, a method of manufacturing the thermal print head having the above configuration will be described with reference to the drawings.

FIG. 3 to FIG. 6 are explanatory views showing the steps of the method for manufacturing a thermal print head according to the present invention.

First, as shown in FIG. 3, a film is formed on the entire surface of the substrate 10 by a printing film forming method or the like, and is baked at, for example, about 1300.degree.
An n1 glaze layer 20 is formed. The thickness Tn1 is
For example, it is about 80 μm.

Next, as shown in FIG.
Is divided into a portion corresponding to a print portion P and a plane region S. The glaze layer 20 having a sectional shape as shown in FIG.
It is formed by removing unnecessary portions by photo-etching using a mask or the like. At this time, the unnecessary portion is not completely removed, but may be 20 to 3 for example.
The thickness Tn2 of about 0 μm is left. In a state immediately after the etching, a relatively angular concave portion H is formed between the print portion P and the plane region S. This concave portion H corresponds to a glaze lower layer 20C described later.

Further, the glaze layer 20 after the etching is cooled again after baking, so that the thermal storage glaze layers 20A, 20B which are thickest and bulge at the print portion P and the plane region S as shown in FIG. Then, a relatively thin glaze lower layer 20C is formed integrally with the heat storage glaze layers 20A and 20B. At this time, firing is performed in a state where the substrate 10 and the glaze layer 20 having different thermal characteristics are in contact with each other.
Although the concave portion H having an angular shape shown in FIG. 4 has a gradually smoother surface shape, even the concave portion H closest to the surface of the substrate 10 has a thickness Tn2 of the lower glaze layer 20C, and therefore, the entire glaze layer 20 has a flat surface. Such a temperature change is caused. That is, the heat storage glaze layers 20A, 20B
From the uppermost portions 20Aa and 20Ba to the lower glaze layer 20C
Even in the skirt portion Y that gradually becomes thinner, a rapid temperature change does not occur partially, and no trouble such as crystal precipitation occurs in the skirt portion Y. In addition, since the heat storage glaze layer 20A of the printing part P and the heat storage glaze layer 20B of the plane area S are smoothly connected via the lower glaze layer 20C, the longitudinal direction along the surface of the heat storage glaze layer 20A at the printing part P The swell of the direction,
It can be suppressed to 0.5 μm / mm or less, whereby the printing on the hard printing target M such as a plastic card can be made good.

Subsequently, the heat storage glaze layers 20A, 20B,
After the lower glaze layer 30C is formed in a desired shape, a thin film of the heating resistor 30 and the electrode layer 40 is sequentially formed over the entire surface by sputtering, as shown in FIG. By performing an etching process by a lithography method or the like, a linear heating resistor 30 and an electrode layer 40 as shown in FIG. 2 are formed. At this time, a predetermined portion of the electrode layer 40 in the printing portion P is removed by an etching process, whereby a small hole 40a is formed in the electrode layer 40.

After forming the heating resistor 30 and the electrode layer 40 as conductors, finally, as shown in FIG. 1, the surfaces of the heat storage glaze layers 20A, 20B and the lower glaze layer 30C are covered while covering these conductors. The protective layer 50 is formed as a thin film by a sputtering method so as to cover the whole.
At this time, the protective layer 50 is formed as a heat storage glaze layer 20 serving as a base.
By depositing and growing vertically upward on the surfaces of A, 20B and the lower glaze layer 30C, a shape similar to the surfaces of these glaze layers is formed. That is, the protective layer 50 has such a form that it falls smoothly between the print portion P and the plane region S. Therefore, when the protective layer 50 is formed, the hem portion Y that gradually becomes thinner from the uppermost portion 20Aa, 20Ba of the heat storage glaze layers 20A, 20B to the lower glaze layer 20C has a gentle surface shape, and is formed by so-called step coverage growth. A continuous protective layer 5 having a smooth surface shape according to the shape of the base and having a substantially uniform thickness without tearing.
0 is formed.

Therefore, according to the method of manufacturing a thermal print head having the above-described structure, the thermal storage glaze layers 20A and 20B in the printing area P and the plane area S are fired at a high temperature and then cooled to form a bulge. Since the lower glaze layer 20C having a certain thickness Tn2 is formed integrally with the heat storage glaze layers 20A and 20B, it is possible to effectively prevent crystal precipitation that occurs in the glaze layer near the surface of the substrate 10. Protection layer 5 formed on heat storage glaze layers 20A and 20B.
It is possible to obtain a thermal print head in which the printing state on the printing object M is good with 0 being a smooth surface.

The heat storage glaze layers 20A and 20B extending from the printing portion P to the plane region S are formed by the low glaze layers 20A and 20B.
When the protective layer 50 is formed as a thin film by a sputtering method, the thermal storage glaze layers 20A and 20B and the lower glaze layer 20C, which are the underlying layers, are formed by the so-called step coverage growth. The protective layer 50 can be uniformly deposited and grown without causing a fracture, and the peeling of the protective layer 50 due to the fracture due to the step coverage growth can be prevented. That is, since there is no tear in the protective layer 50 at the print site P, the contact of the print object M causes the protective layer 50 from such a tear portion.
Does not occur, and good printing performance can be maintained over a long period of time.

The present invention is not limited to the above embodiment.

For example, the same configuration can be adopted for a thick film type different from the present embodiment.
The same effect as that of the present embodiment can be achieved.

The object to be printed is not limited to a card or cardboard, but can be applied to plain paper other than these.

Further, the design and the thickness of the glaze layer can be appropriately changed according to the specifications, and are not limited to the values and the print film forming method described in the above embodiment. The method for forming the conductor and the protective layer is not limited to the sputtering method, and other film forming methods may be employed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a thermal print head according to the present invention.

FIG. 2 is a plan view showing a portion pointed by an arrow P in FIG. 1 from a top surface side.

FIG. 3 is an explanatory view showing one step in a method of manufacturing a thermal print head according to the present invention.

FIG. 4 is an explanatory view showing one step in a method of manufacturing a thermal print head according to the present invention.

FIG. 5 is an explanatory diagram for explaining one process in the method of manufacturing a thermal print head according to the present invention.

FIG. 6 is an explanatory diagram for explaining one process in the method of manufacturing a thermal print head according to the present invention.

FIG. 7 is a cross-sectional view showing an example of a thin-film type thermal print head as a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Substrate 20A, 20B Thermal storage glaze layer 20Aa, 20Ba Uppermost 20C Glaze lower layer 30 Heating resistor (conductor) 40 Electrode layer (conductor) 50 Protective layer P Printing part S Flat area Y Foot part

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiyuki Fujita 21 Ryozaki-cho, Saiin, Ukyo-ku, Kyoto F-term in Rohm Co., Ltd. (reference) 2C065 JC09 JH05 JH10 JH12 JH14

Claims (6)

[Claims] 1. A thermal storage glaze layer is formed in a bulging manner on a printing portion on a surface of a substrate and a predetermined plane region separated from the printing portion, and a conductor is formed on the thermal storage glaze layer. A thermal print head obtained by forming a protective layer so as to cover the thermal storage glaze layer and the conductor from above, wherein the thermal storage glaze layer in the printing region and the planar region has a lower glaze lower layer than their top. A thermal printhead, wherein the thermal printhead is integrally connected to each other. 2. The thermal printhead according to claim 1, wherein the lower glaze layer is formed gradually and continuously from the uppermost portion of the thermal storage glaze layer into a skirt shape. 3. The thermal printhead according to claim 1, wherein a driving chip electrically connected to the conductor is mounted on the plane area. 4. A thermal storage glaze layer is bulged in a printing area on a surface of a substrate and a predetermined plane area separated from the printing area, and a conductor is formed on the thermal storage glaze layer. A method of manufacturing a thermal print head obtained by forming a protective layer so as to cover the thermal storage glaze layer and the conductor from above, wherein when forming the thermal storage glaze layer in the printing region and a planar region, A method for manufacturing a thermal printhead, wherein a lower glaze layer lower than the uppermost part is integrally formed so as to be continuous with each other. 5. The thermal printhead according to claim 4, wherein the lower glaze layer is formed gradually and continuously from the uppermost portion of the thermal storage glaze layer into a skirt shape. 6. The heat storage glaze layer and the lower glaze layer are formed by forming a glaze layer over the entire surface of the substrate, removing a predetermined thickness from portions other than the printing portion and the flat region by etching, and further firing. The method of manufacturing a thermal print head according to claim 4, wherein the thermal print head is formed by: