JPS6021263A - Base board for end surface type thermal head - Google Patents

Abstract

PURPOSE:To improve heat generating efficiency, by setting the length of the flat surface part of at least one end surface of a plate shaped base board having an almost rectangular cross-sectional area of 1-2.5mm., and providing an electric insulating glaze layer, of which the heat conductivity is lower than that of the aforementioned base board, to said end surface. CONSTITUTION:A ceramic base board 6a is formed into a plate shape and the all constitutional surfaces thereof are constituted of flat surfaces which are, in turn, processed with high accuracy. A glass glaze layer 6b is formed to the end surface 7 of the ceramic base board 6c so as to set the length A of the central part thereof to about 80mum. The aforementioned glass glaze layer 6b is formed by baking the glass 6b' applied to the end surface 7 of the ceramic base board 6a and has a shape of which the central part becomes high by the surface tension force of the glass 6b' in a molten state during baking. When the thickness (t) of the ceramic base board 6a is uniformly finished over the total width of said board 6a, the glaze layer 6b can be formed so as to have radius of curvature R after baking.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Use The thermosensitive recording method has excellent maintainability and is therefore used as printers for many terminals including facsimile machines. Furthermore, in recent years, thermal transfer methods have been developed a lot, making it possible to perform multi-color recording or full-color recording, and are being developed as new recording devices. The present invention relates to the structure of the heating element substrate of this thermal head for heat-sensitive recording.

A conventional thermal head and its heating element substrate will be described below.

FIG. 1 shows a thermal transfer recording device using a conventional thermal head, in which 1a is image receiving paper, 1b is transfer paper, and 2
is a paper feed roller, 3 is a thermal head, and the thermal head 3 has heating elements 3b formed in a row on one of the two main planes of the heating element substrate 3a, so this system is called a planar thermal head. I'll decide.

In FIG. 1, transfer paper 1b, image receiving paper 1! When the heating element array 3b is heated in accordance with the image signal while the heating element array 3b is brought into pressure contact with the heating element array 3b of the thermal head 3 and is fed in the direction of the arrow, recording can be performed on the image receiving paper 12L. If a direct coloring type thermal recording paper is used instead of the image receiving paper 1a+transfer paper 1b, a normal direct thermal recording can be obtained.

In this method, the thermal head 3 has a heating element driving semiconductor element connected to each heating element 3bK or a common electrode part of the heating element on the side on which the heating element is formed to facilitate heating of the heating element 3b. For the purpose of mechanically protecting the lead wires connected to the electrode protection cover 4a and heating element driving semiconductor element cover 4b, each is provided. Receiving paper 1
a. It is necessary to prevent the transfer paper 1b or the paper feed roller 2 from coming into contact with anything other than the heating element. For this purpose, the heating element substrate 3 must be made larger, which may lead to an increase in the size of the thermal head, an increase in price, etc. There was a problem.

In FIG. 2, the thermal head 5 has a heat generating body 5b formed on the top of a heat generating body substrate 5a having a hollow shape. The heating element substrate 6a was attached to the base 6C, and was provided in the vertical direction of the apparatus. Hereinafter, the head having the configuration as shown in FIG. 2 will be referred to as an end-face type thermal head. The movement of the recording device is similar to that shown in FIG. By the way, when performing color recording using thermal recording, the recording section can be configured to reduce color shift of multicolor transfer dots by a method as shown in FIG.

In FIG. 3, the image receiving paper 1a is wound around a rotating drum 2' and fixed, and in this state, the image receiving paper 1a is pressed against the heating element 6b of the thermal head 5 via the transfer paper 1b.
As the rotating drum 2' rotates, the image receiving paper 1b is sent in the direction of the arrow. For example, cyan, yellow,
Magenta and black transfer layers (not shown) are applied approximately to the outer periphery of the rotating drum 2 and to a unit length. Therefore, each rotation of the rotating drum 2' produces cyan and yellow.

Color recording can be obtained by transferring each color of magenta and black (heating the heating element according to the image signal). In this case, the overlapping position of each color is
Adjusted by the rotational position of.

Even if the planar head shown in FIG. 1 is used, it is possible to construct a recording section as shown in FIG. 3 of the whistle.

However, in this case, the outer circumference of the rotating drum 2' needs to be at least longer than the short side of the recording screen, and naturally the rotating drum 2' has a longer rotational length than the paper feed roller 2 shown in FIG. Drum 2' becomes larger.

Therefore, in order to prevent the rotating drum 2' from coming into contact with the electrode protection cover 4a of the thermal head 3 and the heating element drive semiconductor element cover 4b, it is necessary to increase the size of the heating element substrate 3a, and as the thermal head becomes larger, Prices will rise dramatically.

Further, as shown in FIG. 2, if an end-face type thermal head is used, the recording section can be configured so that the recording state can be checked quickly.

From such a simple comparison, the usefulness of the edge type thermal head in the thermal recording system is clear, but in the thermal recording system, the planar thermal head is generally used.

Conventional heating element substrates for edge-type thermal heads have a semicylindrical or rod-like shape, and in order for the heating element to be in uniform contact with the recording paper throughout the arrangement, it is necessary to form the heating element. High-precision machining of the curved surface of the heating element substrate is difficult, and in order to improve the thermal characteristics of the heating element, a glass glaze is generally formed on the heating element forming surface, but it is difficult to uniformly form this on the curved surface. difficult things,
Mounting the heating element substrate on a base to give it mechanical strength has had various problems, such as a difficult structure and further difficulty in processing the electrodes of the heating element.

OBJECTS OF THE INVENTION The present invention solves the problems of the prior art, and it is an object of the present invention to provide a heating element substrate that can form an end-type thermal head at low cost using a node ring 1.

Structure of the Invention The present invention has a heating element substrate in the form of a plate, the length t of the flat portion of the end face is I MM <-t (2.5 mm), and a glaze layer is provided on the flat end face. 11" By providing two common electrode signal electrodes on the one-degree heating element forming surface and the two main planes of the flat plate, read processing can be performed using the same electrode connection technology as conventional flat thermal heads. It is.

DESCRIPTION OF THE EMBODIMENTS FIG. 4 is a cross-sectional view of a heating element substrate for an edge type thermal head in an embodiment of the present invention. In FIG. 4, 6 is a heating element substrate, 6a is a ceramic substrate, and 6b is a glass glaze layer.

The substrate ea (hereinafter referred to as a ceramic substrate) made of a ceramic material is plate-shaped and has all flat surfaces, which are processed with high precision (flatness). Since all surfaces of the ceramic substrate 6a are flat,
When processing that surface, it can be processed more easily and with higher precision than conventional curved surfaces. The glass and sglaze layers 2L are configured so that the central portion has a length AK of approximately 80 μm on the end surface 7 of the ceramic substrate 61L. As shown in FIG. 5, the glass glaze layer 9b is formed by applying glass 6b to the end portion 7 of the ceramic substrate 6a,
When this is fired at a high temperature, the glass 6b' becomes molten during firing, and due to surface tension takes on a medium-height shape as shown in FIG. Of course, the amount (or coating thickness) of 6b was adjusted so that the coating would reach a thickness of 80 μm after firing. The fired glaze layer 6b has approximately the same shape as a circle passing through the edges 8 and 9 of the end face of the ceramic substrate 62L and the apex of the glaze layer. Therefore, if the thickness t of the ceramic substrate 6a is finished uniformly over the gold plate, the glaze layer 6b can be formed with a radius of curvature R when fired, and the straightness of the apex can be maintained with high precision. can do.

The radius of curvature R of the surface of the glass glaze layer 6b greatly influences the characteristics of the thermal head.

As shown in FIG. 6, a heating element 10 is formed on the glass glaze layer 6b of the heating element substrate 6, and a common electrode 11 is formed on the glass glaze layer 6b of the heating element substrate 6.
, the image signal electrodes 12 are extended and integrally formed on the main planes 13 and 14 of the heating element substrate 6, respectively, and a wear-resistant layer 15 is further formed as shown in FIG. When forming the heating element 10, the heating element 10 is formed in a concave shape with a step B in order to form an electrode on the upper layer of the heating element 10.

Therefore, when recording is performed by pressing recording paper or transfer paper (not shown) against the heating element 1o, the thermal efficiency is poor and a large amount of power (energy) is required to heat the heating element 10. Although the difference B was several micrometers (0.5 to 2 micrometers), this greatly deteriorated the thermal efficiency.

However, if a glaze layer is provided at the end as described above,
The glass glaze layer 6b can be configured to have a radius of curvature R, and the heating element 10 can be made convex as shown in FIG. 8, thereby improving thermal efficiency.

Now, the radius of curvature R is between the edges 8 and 9 at both ends of the ceramic substrate 62L and the apex of the glass glaze layer (the thickness of the glass glaze) V
Since the thickness A of the glass glaze layer is regulated from the viewpoint of thermal efficiency (heat trapping, etc.), it is determined by the length of the flat part of the end face 7, that is, the length t in Fig. 4. Become. In FIG. 4, when the thickness t is about 1.0 mm, the radius of curvature R is about 2 mm, and when the thickness t is 2.6 mm, it is about 1 mm.

The length L of the heating element 10 varies depending on the recording density, but is approximately 1
It is about 00 to 300 μm. At this time, the amount l of the protrusion of the apex of the heating element is as shown in the table below.

When the thickness t is smaller than 1 mm, the formation error of the glaze layer 6b (assuming it is about 20 μm) is about 1111 R from K.
There is a difference around i11, but in this case, l is 300 μm
In this case, the difference in level becomes sharp and the contact between the end of the heating element and the recording paper or the paper feed roller becomes poor, which is undesirable.

When the thickness t becomes 2.6 mm or more, the formation error (assuming it is about 2 0 μm) of the glaze layer 6b R varies by about 2 degrees, and conversely the protrusion amount 4 becomes too small and becomes ineffective.

Also, when the thickness t exceeds 2.5 mm, the edge 8 at the end
, 9, the glaze layer 6b becomes rough, which may be the cause of poor formation of the electrodes (particularly the image signal electrodes 12).

Next, in the exposure when photolithographically forming the heating element 101, picture frame outer electrode 12, and common electrode 11 on the heating element substrate 6, if at least a positive resist is used, the edges can be sufficiently patterned using a conventional plane mask. It was confirmed that it can be formed.

As described above, according to the heating element substrate of this embodiment, it is possible to easily obtain a curved end face with high precision and to improve the heat generation efficiency of the heating element.

FIG. 9 shows a second embodiment. 9, the difference from FIG. 4 is that the edges 8 and 9 of the end surface 7 of the ceramic substrate
This is the point where the chamfer was applied. At this time, edge 8 in Figure 4
, 9 are at the positions shown at 8' and 9' in Fig. 9, and the distance between them is t.
becomes. At this time, the curvature R is determined by t and the thickness of the glaze layer, as described above.

In this case, the thickness t' of the substrate 6 becomes thicker, but due to the chamfering, a glaze layer is also formed on the chamfered part, and the image signal electrode,
The format of the common electrode can be facilitated. It has been confirmed that even with this method, if the chamfering is only about 0.5 lines, it is possible to produce a pattern with about 8 lines/cut by using at least a plane mask and a positive resist.

In this embodiment, although the chamfer is straight in FIG. 9, it goes without saying that it may be in a rounded shape.

It goes without saying that a glaze layer may be provided on a portion other than the end face.

Further, in this embodiment, the substrate is made of a ceramic material, but it goes without saying that it may be made of other materials.

Effects of the Invention The heating element substrate of the present invention has a drawing surface formed of a plate-like plane, and a glaze layer formed thereon with a curvature, with the planar length of the end surface being 1 to 2.5 mm. This makes it possible to improve the precision of the heating element forming surface, to form the heating element and electrodes using conventional techniques, and to improve the thermal efficiency of printing, making it possible to easily manufacture high-performance thermal heads. This is something that contributes to the dog's hearing.

[Brief explanation of the drawing]

Figure 1 shows a conventional transfer-type thermal recording device, Figure 2 shows a transfer-type thermal recording device using a conventional edge-type thermal head, and Figure 3 shows a conventional transfer-type thermal recording device using an edge-type thermal head. FIG. 4 is a diagram showing a heat generating substrate according to the first embodiment of the present invention; FIG. 5 is a diagram showing a process of forming a glaze layer on the heat generating substrate according to the present invention. 6 is a diagram showing a state in which a heating element and electrodes are formed on a heating element substrate of the present invention, FIG. 7 is a cross-sectional view showing the configuration of a conventional planar thermal head, and FIG. FIG. 9 is a partial cross-sectional view showing a state in which a heating element and electrodes are formed on a heating element substrate, and FIG. 9 is a diagram showing a second embodiment of the heating element substrate of the present invention. 6... Heating element substrate, 6a... Ceramic substrate, 6b... Glass glaze layer, 7...
...End face, 1o... Heating element, t...
length. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 6 Figure 7 Figure 8 Figure 9

Claims (1)

[Claims] The length t of the planar portion of at least one end surface of a plate-shaped substrate having a substantially rectangular cross section is 1≦t≦2.6 mm, and at least the one end surface has lower thermal conductivity than the substrate. A substrate for an edge-type thermal head characterized by having a glaze layer made of an electrically insulating material.