JPH05177855A - Method for forming glaze layer on heating element forming substrate and thermal head substrate - Google Patents

Abstract

PURPOSE:To thickly form a glaze layer on a heating element forming substrate inclusive of the recessed part of the substrate so as to accurately obtain the thickness of the glaze layer immediately under a heating element row and to provide a thermal head substrate. CONSTITUTION:When a glaze layer is formed on a heating element forming substrate 3 having unevenness, a glaze layer 2a is formed on the protruding part of the substrate 3 by printing and a glaze layer 2b is formed on the recessed parts thereof by spraying. A thermal head substrate has the protruding part 3a formed on the heating element forming substrate 3, the glaze layer 2a formed on the top part of the protruding part 3a, the flat part 3b other than the top part of the protruding part 3a of the substrate 3 and the glaze layer 2b formed on the planar part 3b and wall surface parts 3c other than the protruding part 3a of the substrate 3 by spraying and a heating element row 1 is formed on the top part of the protruding part 3a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head used for heat-sensitive recording or thermal transfer recording, and particularly to formation of a glaze layer in a thermal head suitable for use in ticket vending machines, prepaid cards, bar code printers and the like. And a thermal head substrate obtained by the method.

[0002]

2. Description of the Related Art In a thermal head substrate, a glaze layer made of glass is formed under a row of heating elements for the purpose of storing heat or smoothing a conductor pattern forming surface. .. The thermal head includes a flat head (a head having a structure in which the substrate is fixed to the flat surface of the heat sink and a heating element array is formed on the surface of the substrate) and an end face head (a heating element array is formed on the end surface of the substrate). Head).

In the manufacture of a flat head, as shown in the side view of FIG. 3A, when the glaze layer 2 is formed on a flat alumina substrate 3, a glaze paste is applied by patterning by a printing method, or Alternatively, the entire surface is coated. In this case, when there is unevenness having a large step as shown in the figure, the glaze layer 2 is not printed on the concave portion a,
There is a problem that it is difficult to print the entire surface of the uneven substrate by glaze, and it is difficult to form a conductor pattern in a portion where the glaze layer 2 is not formed.

On the other hand, when the glaze layer 2 was formed on the substrate 3 used for the end face head or the serial printer head shown in the perspective view of FIG. 3B, the glaze paste was applied by the spray method. If
Since the paste is sprayed onto the substrate 3 in a sprayable state (that is, with a large amount of solvent), the paste easily flows, and as a result, the glaze layer 2 cannot be formed thick and the glaze layer is not formed. There is a problem that it is difficult to control the thickness of No. 2 and it is difficult to obtain the glaze layer 2 having a constant thickness that can obtain a desired heat storage effect.

The present inventor has also developed a thermal head shown in the side view of FIG. 3C as a thermal head for printing on a hard material such as a card of the ticket vending machine. This is done by fixing the heating element forming substrate 3 to the surface (which may be an end surface) of the heat sink 5 made of aluminum or the like, and at the same time, the heating element driving IC 8 (4
Is a printed wiring board for external connection on which an IC 8 is mounted). In a thermal head equipped with a cover 6, the heating element forming substrate 3 is provided with a convex portion 3a, and the heating element array is provided on the top of the convex portion 3a. And the height H ₁ of the convex portion 3a from the heat sink 5 is set to a height H ₂ or more of the cover 6 (the height of the convex portion 3a itself is set to 0.8 mm or more, for example). ), When printing on a hard material such as card 7,
The card 6 or the like is prevented from being stuck to the cover 6 and hindering printing or feeding.

Also in the substrate 3 having such a convex portion 3a, as described above, it is difficult to obtain a desired and accurate thickness in the glaze layer 2 directly below the heating element array by the spray method. Further, in the case of the printing method, printing can be performed only on the tops of the convex portions 3a, and the substrate material is exposed, so that there is a problem that fine lines such as electrodes cannot be satisfactorily formed by the film forming technique.

In view of the above problems, the present invention provides a heating element forming substrate in which the thickness of the glaze layer directly below the heating element row can be obtained with high precision and can be thickened, and further the glaze layer can be formed in the concave portion. An object of the present invention is to provide a method for forming an upper glaze layer and a thermal head substrate.

[0008]

In order to achieve this object, the method for forming a glaze layer on a heating element forming substrate according to the present invention is such that when a glaze layer is formed on an uneven heating element forming substrate, convex portions are formed. The glaze layer is formed on the substrate by a printing method, and the glaze layer is formed on the concave portion of the substrate by a spraying method.

Further, the thermal head substrate according to the present invention comprises a convex portion formed on the heating element forming substrate, a glaze layer formed on the top of the convex portion by a printing method, and the convex portion of the substrate. And a glaze layer formed by a spray method on the wall surface of the convex portion other than the top portion, and a heating element array is formed on the top portion of the convex portion.

[0010]

In the method of the present invention, since the glaze layer is formed on the convex portion by the printing method in which the paste having low fluidity is applied, the glaze layer can be formed thick and the thickness accuracy can be obtained. In addition, since the glaze layer is formed on the concave portion by spraying a fluid paste, the glaze layer is formed uniformly.

[0011]

EXAMPLE FIG. 1A is a perspective view showing an example of a heating element forming substrate 3 obtained by the method of the present invention.
This is an example in which the present invention is applied to the flat head shown in FIG. In addition, FIG. 1B is an example in which the substrate 3 of this embodiment is applied to an end face head. The substrate 3 is provided on the top of the convex portion 3a,
It has a glaze layer 2a formed by a printing method, a flat surface portion 3b other than the top of the convex portion 3a and a slanted wall surface portion 3c of the convex portion 3a, and a glaze layer 2b formed by a spray method. The heating element row 1 is formed on the top of the shaped portion 3a by vapor deposition or the like. Further, although conductors and protective layers to be electrodes are formed on the glaze layers 2b and 2a, they are not shown.

FIG. 2 is an example of a process of forming the glaze layers 2a and 2b. For example, after laminating green sheets to be an alumina substrate, mechanical grinding is performed and firing is performed, or the alumina substrate after firing is removed. By Fig. 2
As shown in (A), a material 3A having irregularities corresponding to a plurality of substrates 3 is prepared, and a glaze layer 2a is formed on top of the convex portions 3a by a printing method.

After that, as shown in FIG. 2B, a mask 11 covering a portion corresponding to the top of the convex portion 3a is applied, and a spray device 13 applies a glaze paste having a large fluidity to the material 3A. Then, as shown in FIG. 2C, the glaze layer 2b is formed on the wall surface portion 3c and the flat surface portion 3 on both sides of the convex portion 3a.
Form b and bake.

After that, the heating element row 1, the electrode wiring, and the protective film are formed by the film forming technique, and then, as shown in FIG.
A plurality of substrates 3 can be manufactured at a time by cutting each individual substrate 3 at the position indicated by the line 12 in (C).

As described above, the glaze layer 2a is formed by the printing method.
When formed, the layer thickness is 30 ± 3 μm to 120
It can be accurately formed in the range of ± 12 μm (30 to 120 μm ± 10%). On the other hand, when using the spray method, 30μ
It can be formed to a thickness of about m.

In the above-described embodiment, the formation of the glaze layer 2a by the printing method precedes the formation of the glaze layer 2b by the spraying method, but conversely, the formation of the glaze layer 2b by the spraying method may precede. ..

[0017]

According to the present invention, since the glaze layer of the convex portion is formed by the printing method of applying the paste having low fluidity, the glaze layer can be thickened and the thickness accuracy can be obtained.

Since the glaze layer is formed on the concave portion by spraying a fluid paste, the glaze layer can be formed even if the substrate has irregularities of 0.8 mm or more as described above. Are evenly formed. Therefore, the glaze layer can be formed regardless of the unevenness, and the recessed portion and the inclined surface can be formed on the smooth surface, so that the fine lines and the like to be the electrodes and the like can be favorably and easily formed. As a result, productivity can be improved, yield can be improved, and cost can be reduced.

[Brief description of drawings]

1A and 1B are a perspective view and a cross-sectional view showing an example in which an embodiment of a substrate according to the present invention is applied to a flat head and an end face head, respectively.

2A to 2C are process drawings for explaining an embodiment of the method according to the present invention.

3A is a side view of a substrate showing a glaze layer formed by a conventional printing method, FIG. 3B is a perspective view of a substrate showing a glaze layer formed by a conventional spraying method, and FIG. 3C is developed by the present inventors. It is a side view of the thermal head which is doing.

[Explanation of symbols]

 1 heating element row 2a glaze layer by printing method 2b glaze layer by spray method 3 heating element forming substrate 3A material 3a convex portion 3b flat surface portion 3c wall surface portion 5 heat sink 11 mask 12 cutting line 13 spray device

Claims (2)

[Claims] 1. When a glaze layer is formed on an uneven heating element forming substrate, the glaze layer is formed on the convex portion by a printing method, and the glaze layer is formed on the concave portion of the substrate by a spray method. A method for forming a glaze layer on a heating element forming substrate. 2. A convex portion formed on the heating element forming substrate, and a glaze layer formed on the top of the convex portion by a printing method.
A flat portion other than the top of the convex portion of the substrate and a glaze layer formed by a spray method on the wall portion of the convex portion, and a heating element row is formed on the top of the convex portion. A thermal head substrate characterized in that