JPH0234572Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a thermal pen.

Currently, thermal pens are increasingly being used instead of ink-type recording pens because there is no need to worry about ink scattering or ink shortages, and there is no need for troublesome recording management. A conventional thermal pen has a power supply conductor 2 disposed on the top surface of a ceramic substrate 1 forming the thermal pen tip, as shown in elevation and plan view in FIGS. 1A and B of the accompanying drawings. A heating resistor 3 formed as a thick film so as to span between
It is equipped with what was formed. The heating resistor 3 is
Usually covered by a wear-resistant layer (not shown). With this type of traditional thermal pen, manufacturing
When forming a thick film, the position of the conductor and the heat generating resistor tends to shift, and in mass production, the conductor and the heat generating resistor are easily overlapped on the pattern, so even if the heat generating resistor is slightly misaligned, the power resistance, resistance value, etc. The heating resistor was formed in an elliptical shape to obtain sufficient electrical characteristics.
That is, as shown well in Figure 1B,
Width dimension in the direction spanning between the conductors of the heating resistor 3
W ₁ is considerably larger than the width W ₂ in the direction orthogonal thereto. If the shape of the heating resistor is made into such an elliptical shape, as illustrated in FIG. 3'
Since it still completely spans between the conductors 2, no problem arises in terms of electrical characteristics. Therefore,
Conventional thermal pens with an elliptical heating resistor do not require very strict alignment and are suitable for mass production, and there are almost no problems with electrical characteristics. It has the disadvantage that directionality tends to appear. For example, as shown in FIG. 3, a conventional thermal pen 10 as described above is swung in the direction of the long width W 1 of the heating resistor ₃ while crossing the thermal recording paper 4 moving in the direction of the arrow A. When the recording curve 11 is set so that the line width is uneven, the resulting recording curve 11 will have uneven line width. That is, the peak portions 11A, the valley portions 11B, and the portions 11C parallel to the paper 4 of the recording curve 11 tend to be thicker than other portions, and the thickness of the recorded line obtained differs depending on the recording direction. Therefore, with conventional thermal pens, accurate records may not be obtained or the records may be difficult to see. A pen is requested.

In view of these demands, the purpose of the present invention is to provide a thermal pen whose drawing performance remains unrestricted until the end of its lifespan.

Next, the present invention will be described in detail regarding embodiments of the present invention.

Figures 4A and 4B of the accompanying drawings are elevational and plan views of a thick film thermal pen tip having a round heating resistor. This heat pen tip 20
is manufactured as follows. alumina,
A thermal insulating layer (not shown) or a porous insulating layer (not shown) to facilitate printing is provided on the top surface of an insulating base material 21 made of well-known ceramic such as steatite and formed into a predetermined shape. After printing and baking, the power supply conductor 22 is printed and baked to a predetermined thickness in a pattern as shown in FIG. 4B. Although these insulating layers are not necessarily required, it is preferable to provide them in order to improve the rise of thermal response or to print fine lines. Furthermore, after printing, a round heating resistor 23 is dried and fired so as to span between these conductors 22. Next, a wear-resistant layer (not shown) made of special glass, glass containing various fillers, crystallized glass, etc., which covers at least the round heating resistor 23, is printed and fired. The forming method in each step is not limited to printing, and any well-known thick film forming method such as a spray method or a transfer method may be used, and the steps in which simultaneous firing can be performed can be performed by simultaneous firing. In the thermal pencil tip 20 having such a structure, only the shaded part in FIG. ing. As shown in FIG. 3, when this thermal pen 20 is installed so as to be swung across the thermal recording material 4, that is, in the same manner as the thermal pen 10 described above, the obtained recording curve 12 is uniform everywhere. It becomes thick. Furthermore, such a thermal pen 2
0, power 0.9W (DC), contact pressure 15-20g,
When we repeated the life confirmation test at a vibration width of 40 mm and 5 Hz, the lifespan was more than 500 km in all cases, and no directionality was visually observed.

5A and 5B show an embodiment of the thermal pen tip of the thermal pen of the present invention, which further improves the characteristics of the thermal pen shown in FIG. 4, and FIG. 5A is a plan view thereof. 5B is a sectional view taken along the line BB in FIG. 5A. Heat pen tip 20A of this example
is manufactured as follows. Insulating base material 21A
A power supply conductor 22A is formed on the top surface. In this case, in the portion where the heating resistor is provided, the power supply conductor 22A is formed with a curved portion 22B such that the interval between the conductors is narrower at the center. Next, the curved portion 22B of the power supply conductor 22A
A round heating resistor 2 is placed between the
3A is formed. The rest may be the same as described for the thermal pen in FIG. 4. To explain this point in more detail, as shown in FIG. 5A, the heating resistor 23A is formed in a round shape when viewed from the side that contacts the recording paper;
Two power supply conductors 22 located at the bottom of 3A
Each part of A extends symmetrically to each other on both sides of the circular center point of the heating resistor 23A, and the distance between the opposing side edges of each part of the power supply conductor 22A is equal to the extension. In the direction of , the width becomes gradually narrower as it approaches the center point. In this way, each part of the power supply conductor located at the bottom of the heating resistor 23A protrudes from each other toward the center point of the round shape of the heating resistor 23A when viewed from the recording paper side. Since the conductor spacing is the shortest at the center point of the round shape, the heating resistor 2
The central part of 3A is considered to be a heat concentration source. Regarding the thermal pen tip with this structure, its lifespan and non-directionality,
When tests similar to those described above were repeatedly conducted on the thermal pencil tip having the structure shown in FIG. 4, substantially the same results were obtained. Compared to the structure shown in FIG. 4, the conductor 22A is deeply inserted into the center of the heat generating resistor 23A, which results in a relatively small heat generating resistor 23A shown with diagonal lines in FIG. 5A. Since heat generation can be concentrated in the area 23B,
It is suitable for relatively thin line recording, and even if there is a slight misalignment between the conductor and the heat generating resistor, the heat concentration source is at the center, so it has the advantage of reducing resistance value variations and heat generation variations.

FIG. 6 shows a longitudinal cross-section of a thermal pencil tip according to yet another embodiment of the present invention. The heat pen tip 30 of this embodiment is similar to the embodiment shown in FIG. The thickness of the abrasion-resistant layer 35 covering the inner surface of the wear-resistant layer 35 is formed so that it becomes slightly thicker toward the center.
The reason why it is preferable to have such a shape of the wear-resistant layer is as follows. First of all, when the heating resistor is made into a round shape according to the present invention, due to the nature of screen printing, the top of the heating resistor may be flat, or conversely, the center may be concave. There is a tendency for it to become distorted, and this needs to be corrected. Second, as shown in FIG. 7, when the thermal pencil tip 10 is set at an angle with respect to the recording paper 4, whether the shape of the heating resistor 3 is elliptical or circular, the true high-temperature heating section 3A is recorded. This is because the paper 4 may not come into contact with the paper 4 or the contact pressure may become weak, resulting in uneven recording. On the other hand, according to the structure of the thermal pencil tip 30 of the present invention as shown in FIG. Since the bulge at the center of the recording paper 35 can come into contact with the recording paper 4, uneven recording will not occur.
Therefore, the thermal pen tip with the structure shown in Fig. 6 can be easily set without paying much attention to the posture of the thermal pen, and even if the angle with the recording paper is slightly deviated from the right angle or there is some variation in pressure. Even when printing is performed, it is easy to obtain non-directional surface drawings without blurring or thinning of the central part of the recording line, and the effect is particularly pronounced as the recording speed increases.

The insulating base material of the thermal pen tip of the thermal pen according to the present invention may be any material, regardless of the material and shape described above, as long as it matches the properties of the heating resistor material and the conductor material. Furthermore, the shape of the conductor is not limited to the one shown in the above-mentioned embodiments, and can be modified in various ways.As for its material, it is preferable to use one whose main component is Au, but it is preferable to use one whose main component is AgPd, Pt, etc. Any conductive material may be used as long as it is heat resistant and has a low rate of change in resistance of the heating resistor.
As for the heating resistor, a heating resistor material mainly composed of RuO ₂ was used, but the material is not limited to this, and any material may be used as long as it can generate heat at a high temperature and has good heat generation characteristics. As for the wear-resistant layer, it is preferable that the material has as much wear resistance, heat resistance, and thermal conductivity as possible, and a material mainly composed of glass is usually used because it is easy to form.

[Brief explanation of the drawing]

Figures 1A and B of the accompanying drawings are an elevational view and a plan view schematically showing an example of a hot pen tip of a conventional hot pen, and Figure 2 is an example of the hot pen tip of Figure 1 in which the heating resistor is misaligned. FIG. 3 is a schematic diagram illustrating the recording curve of each thermal pen, and FIGS. 4 A and B schematically illustrate the thermal pen tip of a thick-film type thermal pen with a round heating resistor. FIGS. 5A and 5B are a plan view schematically showing an embodiment of the thermal pen tip of the thermal pen according to the present invention and a sectional view thereof taken along the line B-B, and FIG. FIGS. 7 and 8 are longitudinal sectional views schematically showing another embodiment of the thermal pen tip of the pen, and are schematic diagrams for comparatively explaining the operating states of each thermal pen. 20, 20A...heat pen tip, 21, 21A
... Insulating base material, 22, 22A ... Power supply conductor, 22B ... Curved portion, 23, 23A ... Round heating resistor, 30 ... Heat pen tip, 31 ... Insulating base material, 32 ... Electric power Supply conductor, 33... Round heating resistor, 35... Wear-resistant layer.

Claims (1)

[Scope of utility model registration request] In a thick-film thermal pen having a heating resistor formed in a round shape when viewed from the side that contacts the recording paper so as to straddle two power supply conductors formed on the surface of an insulating base material, the lower part of the heating resistor The two portions of the power supply conductor located in the heating resistor extend symmetrically on both sides of the circular center point of the heat generating resistor, and the portions of the power supply conductor are opposite to each other. The thermal pen is characterized in that the distance between the side edges becomes gradually narrower as it approaches the center point in the direction of extension.