JPS5947999B2 - thermal pen - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to thermal pens, and more particularly to thick film thermal pens.

As shown in cross-sectional views in FIGS. 1 and 2 of the accompanying drawings, this type of thermal pen includes electric conductors 2, 2' for power supply and a heat-generating resistor for thermal recording using a thick film technique on an insulating base material 1. It is common to have a structure in which the body 3 and the wear-resistant layer 4 are laminated,
The wear-resistant layer 4 is provided to cover the heat-generating resistor 3 for thermal recording, and protects the heat-generating resistor from abrasion due to sliding contact with the heat-sensitive recording paper.

FIG. 1 shows an example of a thermal pen in which the heating resistor 3 is formed in a dot shape, and FIG. 2 shows an example of a rod-shaped thermal pen in which the heating resistor 3 is formed in a segment shape. Conventionally, this wear-resistant layer has been formed by coating it to a predetermined thickness using a material such as glass or high-temperature glass.

The lifespan of this type of thick-film thermal pen is mostly determined by the lifespan of the heating resistor and the wear-resistant layer, but the rate of change in resistance, drawing performance, and power consumption are greatly affected by the wear-resistant layer. Lifespan is affected. The minimum lifespan of a thermal pen is that it has good drawing performance with a change in resistance of about 20% or less after running for about 500 km by continuously applying a certain amount of power and recording analog data. One of the major features required for thermal pens is that Continuous testing of high-speed analog recording with conventional thick-film thermal pens reveals several problems.

For example, use blue colored paper, frequency 60H2, amplitude 30T.
m, pressure 20V, recording paper speed 10m/min to 50
When rapid thermal recording is performed at 0 Tvn/sec, the resistance change rate is 5
Approximately 10% at approximately 00km (including manufacturing variations)
(In some cases, it exceeds 0% and reaches 20%), and when used at a constant voltage, the color becomes pale, especially,
From the viewpoint of drawing quality, the speed ranges from low speed to standard speed (or normal speed).
Specifically, if the speed of the thermal pen is less than about 1.5 m/sec), the drawing quality will deteriorate slightly, but for practical use it can reach up to 500 km.
There are no particular problems up to this point, but when recording at high speeds of about 1.5 m/sec or higher, the drawing performance of a thermal pen that has been used for around 100 km deteriorates, in other words, the visual contrast disappears and the image appears blurry. The line becomes thicker, magnifying glass (x10)
When looking at the traces of records, the lines are observed as a collection of dots, the color fades quickly, and the records disappear during transportation, resulting in poor preservation.
When similar checks were performed using black colored paper that is less likely to fade, the fading resistance was slightly improved, but the deterioration of the drawing quality was even faster, and the resistance change rate was 4 times higher at about 100K01, and the resistance change was 5 times higher at about 100K01.
At 00 km, it reaches 7 times. At the same time, the drawing performance deteriorates about four times faster than at high speeds, making it unsuitable for high-speed recording, requiring the pen to be replaced, and increasing the total operating cost. When we further investigated these causes, we found that the pen travel distance (
&l), drawing quality and resistance change rate of heating resistor (ΔR=
It was found that the relationship between (R-RO)/RO×100% (RO: initial resistance value, R: resistance value after running) is approximately as shown in FIG.

In FIG. 3, the solid line shows the relationship between the Benn travel distance and the rate of change in resistance, and the dotted line shows the relationship between the Benn travel distance and the drawing quality. In Figure 3, point A is the point where the wear-resistant layer has almost completely disappeared or has begun to disappear and a portion or all of the resistor surface that is in contact with the recording paper is exposed.
It's time to reach the end. From the vicinity of part A, the increasing rate of ΔR (
ΔR/Km) also tends to increase, and the aforementioned deterioration in drawing performance, especially at high speeds, begins to become noticeable. Similar results were also obtained by conducting a J test using a control circuit that can control power consumption to remain constant even when resistance changes (resistance increases). SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the prior art, it is an object of the present invention to provide a thermal vent with long life and good drawing properties.

Next, the present invention will be described in detail with reference to embodiments of the present invention based on the accompanying drawings.

A case in which the present invention is applied to a thermal pen having a cross-sectional structure as shown in FIG. 1 will be described in detail.

In FIG. 1, an insulating base material 1 is formed of an insulating material such as commonly used alumina porcelain, forsterite porcelain, steer 4-tight porcelain, etc., and its shape is not limited to that shown in the illustration and may be freely selected. Electrical conductor 2, 2' for power supply
There are no particular restrictions on the material or structure, but for example, it is made of gold or silver-palladium, and there are no particular restrictions on the material or structure of the heat-sensitive recording heating resistor 3, as long as it is a material that serves as a heating element. For example, the material used in thick film printing such as RuO2 may be used. Although not shown in the figure, a paste absorbing member and heat insulating layer may be formed on the insulating base material 1 in advance. Various studies were conducted on the wear-resistant layer 4 formed to cover the heating resistor 3. First, this wear-resistant layer 4 is placed inside the wear-resistant glass.
An example will be described in which a filler is used which has better heat conduction than glass which is more wear resistant.

First, we conducted research on the amount of filler components mixed in.
Taking alumina powder as a filler as an example, the weight ratio of the glass component and the filler component is 10:0)9:1, 8
:2, 7:3, 6:4, 5:5, 4:6 ratios, add a predetermined amount of vehicle and diluent to make a paste, and form a wear-resistant layer to a predetermined thickness by screen printing. , the characteristics were tested as a heat vent. The test items are as follows. Abrasion resistance and drawing test Contact pressure 20V/chip, frequency 60Hz, amplitude 30-,
Recording paper speed 100-/M, power consumption 1. IW, abrasion resistance (resistance change rate) was investigated for 45 hours continuously.

The recording paper speed was increased to 500-/sec only when high-speed drawing performance was confirmed. 03) Power resistance test using step stress Contact pressure 20t/chip, frequency 60Hz, amplitude 10
-, recording paper speed 10-/min, power consumption 1.3W~
Examine the change in resistance value at 2.0W (increase by 0.IW each, test for 5 minutes at each power) (resistance change rate at final 2.0W) Power consumption test Visually maintain the same recording density How much power do you need to get it? Adhesive strength test Confirm the adhesion state using tweezers under a microscope.The results of these tests are summarized in the table below.

As is clear from the table below, the filler weight ranges from 30 inches to 5 inches.
0% has a smaller resistance change rate ΔR and a longer recording distance to reach point A than others. When the filler weight exceeds 50 inches, the content of the glass component in the wear-resistant layer decreases, so the adhesive strength between the fillers decreases.
The adhesive strength with the heating resistor is weak, and the surface of the wear-resistant layer has almost no luster in appearance, making it easy to peel off. On the other hand, if the weight per filler is less than 30 (F6), the mileage to reach point A will be extremely short, the wear-resistant layer will be worn out, the resistor will be exposed quickly, and the rate of change in resistance will increase greatly.In comparing the power consumption, the weight per filler 30% or more, especially
40 to 5001), even when the power supply to the heating resistor for heat-sensitive recording was cut off and the thermal pen was shaken, the drawing was still blank. Also, power consumption is reduced to 0.
Comparison was made between recording paper on which recording was performed with increasing power of 2W, 0.4W, 0.6W, 0.8W, and 1.0W. Visual observation of the color recording state of the recording paper reveals that the filler content of the wear-resistant layer is 30%.
Is it more likely that the above content is better than the one with a lower content? 1-1 out of 11. In a record preservation test (stored for 66 hours in a 60°C environment) using blue-colored paper, records with a filler content of 30 (F6 or lower) faded to such a thin level that they could not be copied, especially when recording data at high speeds. However, when the filler content was within the range of 30% to 50%, the degree of discoloration was to the extent that copying was possible.The reasons for this may be as follows:Glass (thermal conductivity 0. 002c0!/Cm・Sec・℃, Mohs hardness 4
Compared to the before and after), the filler has (1) high hardness (around 9 on the Mohs scale) and high wear resistance, and (2) good thermal conductivity (0.07 (o(1/1)). (Cm-Sec・℃) Good heat dissipation to the recording paper. (3) A wear-resistant layer made of glass containing 30% or more filler varies slightly depending on the wear-resistant layer formation conditions, such as the amount of filler and firing temperature. However, the smoothness of the surface condition is worse than that of filler weights of 30 Cf6 or less, but this actually improves the contact with the color former of the thermal paper, etc. Regarding the point (3) above, further FIG. 4A, which will be explained in detail, shows a wear-resistant layer 4 containing 30% by weight of filler component 4B with respect to glass component 4A.
Figure 4B schematically shows the state of the cross section when formed at a firing temperature of 570°C. ing. As is clear from a comparison between FIG. 4A and FIG. 4B, at a firing temperature of 550°C, the filler component 4B is dispersed to some extent on the top of the glass component 4A, resulting in fine irregularities on the surface of the wear-resistant layer 4. However, when the firing temperature is set to 570° C., the filler component 4B penetrates into the lower layer of the glass component 4A, and the surface of the wear-resistant layer 4 remains relatively smooth. Therefore, when the filler weight is about 30%, depending on the firing temperature of the wear-resistant layer,
It can be seen that the influence of the filler component on the surface condition of the wear-resistant layer changes greatly. Similarly, FIG. 5A shows 40% by weight of filler component 4B relative to glass component 4A.
Fig. 5B schematically shows the state of the cross section when the wear-resistant layer 4 containing % is formed at a firing temperature of 550°C. The cross-sectional state is schematically shown. Furthermore, FIG. 6A shows that the filler component 4B is 509% by weight relative to the glass component 4A.
Fig. 6B schematically shows the state of the cross section when the wear-resistant layer 4 containing 6 is formed at a firing temperature of 550°C, and Fig. The cross-sectional state is schematically shown. As is clear from the comparison between FIGS. 5A and 5B and between FIGS. 6A and 6B, when the filler weight is 40% and 50%,
The filler component provides fine irregularities on the surface of the wear-resistant layer without being affected by the firing temperature. According to the heat vents shown in FIG. 4A, FIG. 5A and B, and FIG. , When the heating resistor 3 for thermal recording is brought into contact with thermal recording paper and moved at high speed (1.5 m/sec or more) without passing any current, traces of the movement of the thermal pen will be recorded in a faint manner. . This is thought to be due to the effects of frictional heat and fine irregularities on the surface of the wear-resistant layer, and this is thought to result in an increase in recording density during recording with normal power applied. The relationship between the fine irregularities on the surface of the wear-resistant layer and the surface condition of the heat-sensitive recording paper, which are thought to exert such effects, will be examined in more detail.

Figure TA shows an example of the unevenness of the surface of the wear-resistant layer when the filler weight is 40%, and Figure TB shows the unevenness of the surface of the wear-resistant layer when the filler weight is 20%. An example is shown. On the other hand, microscopic observation of the surface of thermal recording paper before recording using a scanning electron microscope reveals that the surface of the recording paper has irregularities due to color formers, fibers, components constituting the backing paper, etc. When the unevenness of the surface is measured, it is found that the difference from the lowest point to the highest point is about 2 to 8 microns, as illustrated in FIG. Therefore, in the case of a thermal pen, unlike a thermal head in which the tip of the tip that contacts the recording paper is desired to have an ideal surface condition such as a glass mirror surface, rather, the tip of the tip in contact with the recording paper is desired to have an ideal surface condition such as a glass mirror surface. If the surface of the abrasion-resistant layer of As illustrated in FIG. 7A, it is thought that if the surface of the wear-resistant layer of the thermal pen has fine irregularities, heat is more easily transmitted to the concave surface portion of the recording paper even during high-speed recording. In fact, when comparing the drawing density based on visual judgment of the recording, the thermal pen in the case of Figure 7A is 40% higher than the thermal pen in the case of Figure TB.
It has been found that the same recording density can be obtained with approximately % less power. Furthermore, in the thermal pen of this example, we investigated the influence of the contact pressure with the thermal paper, and found that even if the contact pressure was increased stepwise such as IOV) 20V, 30f7, 40f, and 50V/pen, the rate of resistance change was It was found that there was no significant difference in the drawing properties, sufficient density was obtained even with a small contact pressure (IOV/pen or less), and the responsiveness to the movement of the thermal pen in response to signals was also improved.

For the above-mentioned reasons, the surface roughness of the wear-resistant layer applied according to the present invention is preferably about 2 to 8 microns, depending on the type of recording paper used and the purpose. Moreover, it goes without saying that the abrasion resistance of the abrasion resistant layer is improved by mixing the filler into the glass in this example, regardless of the unevenness of the surface of the abrasion resistant layer. Next, the results of a study on the particle size of the filler mixed in this embodiment of the present invention will be explained. #600, #8001 #1000, #2000, #40 in JISR6OOl-1973
The same alumina component with a particle size corresponding to 00, #6000, and #8000 is selected as the filler, and as described above, each filler is added and the amount of filler is changed to form a wear-resistant layer to a predetermined thickness. 60Hz, 30m width, 1
A wear resistance test was conducted and observed at 0 to 100 Tm/min, 207/pen, and power of 1.1 W, and the following results were obtained. If the particle size is large (#800 or less), it may damage the recording paper.
For example, unsightly traces may appear when the pen is running even without applying electricity, or the speed of the recording paper may be reduced as much as possible (1
0 Tm/min), and if the frequency of the pen is set to 60 Hz or higher and the amplitude is reduced, the resin that serves as a coloring binder on the surface of the recording paper will melt in a short time and come out together with the paper components. Gas may be generated, and in extreme cases, the recording paper may tear. On the other hand, with fine particles of #8000 or more, if the amount of filler is increased too much, the adhesive strength with the heating resistor will be weakened, and even if an appropriate amount is added, the particle size is too fine and the above-mentioned effect may not be produced. I understand. In the end, it was found that the particle size is preferably between #1000 and #6000. Furthermore, next, the results of a study on the type of filler to be mixed in this embodiment of the present invention will be explained.

As a specific example of a particle having a particle size within the above-mentioned range, a Mohs hardness of 6 or more and a thermal conductivity of 0.004 d/Cln-Sec・℃ or more, the above-mentioned A! , 203, and A with different purity! 2
03 Main ingredients ceramic powder, SiC, ZrO2, Mg
O, diamond powder, BeO, forsterite, etc.
We selected natural or synthetic ceramic powder or crystallized glass with extremely low alkali content as the filler, and repeated the same research.We found that the content differs slightly depending on the powder, but if it is within the range mentioned above, it is within the range. All of them were found to be more effective than other methods.
Further, even when the amount of filler is 30 to 50%, the closer the thermal expansion of the powder is to the base material, heating resistor, or glass component, the smaller the resistance change rate is and the longer the life is. For reference, examples of the physical properties of the powder are summarized in the following table. Next, the results of studies regarding the types of glass used in this embodiment of the present invention will be explained. Experiments conducted on glass ranging from low-melting glass (firing temperature of approximately 450°C) to high-melting glass (firing temperature of approximately 1000°C) found that the higher the firing temperature and the different thermal expansion from other materials, the more difficult the wear-resistant layer becomes. It has been found that there are no particular restrictions, as long as the resistance value before and after firing tends to slightly fluctuate (there is no problem in terms of characteristics). Next, as for the structure of the wear-resistant layer, for example, as shown in FIG. 9, the wear-resistant layer covering the heating resistor 3 may be formed to include two layers 4' and 4''.

In this case, the layer 4' on the side closer to the heating resistor 3 may be mixed with a filler component 4'B with a coarse grain size, and the outer layer 4'' may be mixed with a filler component 4'B with a fine grain size. The reverse may also be used.Also, as shown in Figure 10, the type,
The wear-resistant layer 4'' may be formed by mixing, for example, two types of filler components 4''B and 4''C with different particle sizes.Furthermore, as described above, in addition to these filler components, properties may be improved. Therefore, it is possible to add a minute additive such as a metal, ceramic, or cermet material that does not affect the heating resistor.A wear-resistant layer that exhibits the above-mentioned effect is a thick film heating resistor. It only needs to have a predetermined shape and structure after being baked onto the body, and therefore does not require any special forming method.

For example, known means such as a thick film method using screen printing, spraying, etc., or a transfer method can be used. Additionally, fillers with more acute angles tend to have smaller particle sizes because the recording paper speed is extremely slow and gas is more likely to be generated under conditions of high contact pressure. That is, the more polygonal the cross section becomes and the closer it is to a sphere, the more difficult it is for gas to come out, and therefore the particles tend to be larger in size. FIG. 11 shows an example of the relationship between the running distance (Km) of a hot pen and the rate of change in resistance when lead borosilicate glass whose wear-resistant layer is baked at a temperature of 700°C or less is used.
The figure shows an example of the relationship between mileage and drawing quality.

11 and 12, curve A is for the case without the wear-resistant layer, curve B is for the filler weight of 20%, and region C is for the filler weight of 30-5% as in the above-described embodiment of the present invention.
In the case of 0%, the rate of change in resistance varies slightly depending on the type of glass, the thickness of the wear-resistant layer, the recording paper used and its manufacturer, and the color developed. Further, although higher melting point glasses have better abrasion resistance, they tend to have too small a coefficient of thermal expansion, and because the difference in coefficient of thermal expansion with other constituents tends to become large, the rate of change in resistance tends to increase. In the embodiment of the present invention described above, the wear-resistant layer was formed by inserting a filler into glass, but in another embodiment of the present invention, the wear-resistant layer was formed by using crystallized glass (partially crystallized and A similar effect can be obtained even if it is formed by crystallization (mostly crystallization).

This crystallized glass is formed to a predetermined thickness by precipitating crystalline matter from glass, and any glass ceramic may be used as long as the hardness after crystallization is greater than that of the glass state. In this case, a filler may be added as in the previous embodiment, or it may not be added at all. As is clear from the above, the thermal pen of the present invention has a long life, good drawing performance, and low power consumption, and its principle can be widely applied.

For example, the structure may have different shapes, dimensions, and positions of various members, and the overall structure may be selected by considering manufacturing, usage, reliability, etc., and heating resistors may be placed in dots on thermal recording paper. It can be applied not only to dot-type thermal pens that come into contact with the body as shown in Figure 1, but also to segment-shaped rod-shaped thermal pens as shown in Figure 2, and regardless of the type of recorder, long life is required. It is suitable for general single-color thermal recording machines, X-Y recorders, drawing machines, plotters, as well as multi-color recording machines.
It is also suitable for thermal pens used on materials other than paper that may cause discoloration.

[Brief explanation of the drawing]

Figures 1 and 2 of the accompanying drawings are cross-sectional views schematically showing a structural example of a thermal pen to which the present invention is applied, and Figure 3 is a graph showing the pen travel distance and drawing performance of the thermal pen, and the rate of change in resistance of the heating resistor. Figures 4 to 6 are diagrams showing contrasting differences in the cross-sectional structure of the wear-resistant layer when the amount of filler components is different and the firing temperature is changed. Figure T A is a diagram showing the relationship between filler A diagram showing an example of the uneven state of the surface of the wear-resistant layer when the filler weight is 40%, FIG. 8 is a diagram showing an example of the uneven state of the surface of the wear-resistant layer when the filler weight is 20%, FIG. 9 and FIG. 10 are cross-sectional views showing the structure of the wear-resistant layer as an example of the present invention, and FIG. 11 is a diagram showing the pen travel distance of various thermal pens. FIG. 12 is a diagram showing an example of the relationship between the rate of change in resistance, and FIG. 12 is a diagram showing an example of the relationship between the pen travel distance and the drawing quality of various types of thermal pens. 1... Insulating base material, 2... Electric conductor for power supply, 3... Heat generating resistor for thermal recording, 4
, 4', 4', 4''...wear-resistant layer, 4A...
...Glass component, 4B, 4'B, 4'B, 4''B, 4
``C...Weiler component.

Claims (1)

[Scope of Claims] 1. A thermal pen having a heating resistor for heat-sensitive recording coated with an abrasion-resistant layer at the end of an insulating base material, the abrasion-resistant layer comprising: 2
A thermal pen comprising a glass layer treated to have a rough surface with a surface roughness of .about.8μ. 2 The glass layer includes a glass component and a filler component, and the weight ratio of the glass component and the filler component is 7:3.
The thermal pen according to claim 1, wherein the thermal pen is within a range of 5:5. 3 The filler component has a Mohs hardness of 6 or more, a thermal conductivity of 0.004 cal/cm・sec・℃ or more, and a particle size of #1000 to #6 according to JISR6001-1973.
3. A thermal pen according to claim 2, comprising a ceramic insulating powder in the range of 0.000 to 0.000. 4. The thermal pen according to claim 1, wherein the glass layer is made of crystallized glass.