JPH02301453A - Thermal recording head and thermal recorder - Google Patents

Abstract

PURPOSE:To make a common electrode and discrete electrodes available in every recording system by a method wherein a heating area of a heating resistor layer between the common electrode and the discrete electrodes 1 is covered with a wear- resistant layer, and 1 the common electrode and the discrete electrodes are exposed in the vicinity of the heating area of the heating resistor layer. CONSTITUTION:A wear-resistant layer 25 is formed on a part (heating area) of a heating resistor layer 22 between a common electrode 23 and discrete electrodes 24. Furthermore, wear-resistant layers 26, 27 are formed on the common electrode 23 and the discrete electrodes 24 excepting the vicinities 28, 29 of the heating area. In this thermal recording head, the wear-resistant layer is absent on parts 28, 29 between the layers 25 and 26, 27. Thus, at the parts 28, 29 the common electrode 23 and the discrete electrodes 24 are exposed to directly come into contact with heat-sensitive paper or an ink ribbon. In a thermal recording system, the wear-resistant layer on the heating area is depressed on heat-sensitive paper. In a thermo-transfer recording system, the wear-resistant layer is depressed on a body to be recorded through a thermo-transfer ink ribbon. On the other hand, in an electro-transfer recording system, the exposed vicinities of the heating area are depressed on a body to be recorded through an electro-transfer ink ribbon.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a thermal recording head and a thermal recording apparatus using the same.

(Prior art) Thermal recording devices are non-impact recording devices, so they are characterized by low noise and easy maintenance, so they are widely used as output terminal devices for many office automation equipment, including portable word processors. has been done. There are three types of thermal recording devices: (1) thermal recording devices, (2) thermal transfer recording devices, and (2) electrical transfer recording devices. Hereinafter, these thermal recording devices will be briefly explained using FIGS. 9 and 10.

FIG. 9 shows a schematic diagram of the thermosensitive recording device. In thermal recording, a thermal head 2 in which a large number of heating resistive elements 1 are lined up as shown in FIG. 9(a) is used.
As shown in FIG. 2B, it is brought into pressure contact with the thermal recording paper 3, and electricity is selectively applied to the heating resistor elements 1 on the thermal head 2 according to the recording pattern. The thermal recording paper 3 is a special paper whose heated portion develops color. As Joule heat is generated in the energized heating resistor 1, the heat-sensitive recording paper 3 develops color and an image is formed. The thermal recording device is characterized by having the simplest structure of all thermal recording devices and low installation cost.
Further, although thermal recording paper is a special paper, it is not very expensive and the recording cost is low, and furthermore, since it is possible to perform back and forth recording, the recording speed is high. On the other hand, there are drawbacks such as the fact that it can only be recorded on thermal recording paper, that thermal recording paper reacts to friction and light, making it difficult to preserve recorded images for a long period of time, and that it is susceptible to falsification.

Thermal transfer recording apparatus solves the drawbacks of thermal recording apparatuses, and a schematic diagram thereof is shown in FIG.

The thermal transfer recording device uses the same thermal head 2 as the thermal recording device, and an ink ribbon 6 having an ink layer 5 formed by coating one side of a base film 4 with ink that softens, melts, or sublimates when heated. 1st
As shown in FIG. 0, the thermal head 2 is pressed against the base film 4 side of the ink ribbon 6, and the recording paper 7 is pressed against the ink layer 5 side, respectively, and the heating resistive elements 1 on the thermal head 2 are selectively energized. The Joule heat generated by the heating resistor element 1 softens, melts, or sublimates the ink in the ink layer 5, thereby transferring the ink onto the recording paper 7 to form an image. The advantages of the thermal transfer recording device are that it solves the disadvantages of the thermal recording device, and specifically, the recording paper 7 can be plain paper, the recording can be stored for a long time, and the recording is not falsifiable. It is. However, it also has disadvantages, such as the cost of the ink ribbon being several times higher than that of thermal recording paper, and the fact that recording can only be done in one direction.

Next, a schematic diagram of the current transfer recording apparatus is shown in FIG. Similar to thermal transfer recording devices, electric transfer recording devices soften, melt, or sublimate ink applied to an ink ribbon.
This is a recording device that forms an image by transferring ink onto recording paper, but it differs from a thermal transfer recording device in that the ink ribbon itself generates heat.

This current transfer recording apparatus uses a recording head 9 in which recording electrodes 8 are lined up as shown in FIG. 11(a). on the other hand,
The ink ribbon 10 is composed of a resistive base film 11, a conductive layer 12, and an ink layer 13, as shown in FIG. 11(b). When the recording head 9 and the return electrode 14 are pressed into contact with the ink ribbon 10 and a voltage is selectively applied to the recording electrode 8, as shown by the arrow, the recording electrode 8 - resistive base film 11 → conductive layer 12 - base film 11 - A current flows in the path of the return electrode 14, and when the current flows through the base film 11, Joule heat is generated. Note that the recording electrode 8
Since the area in which the return electrode 14 is in contact with the ink ribbon 10 is very large compared to the area in which the return path electrode 14 is in contact with the ink ribbon 10, the heat that melts the ink layer 13 is generated only directly under the recording electrode 8, and the image is not formed here. Ru.

Compared to a thermal transfer recording device, an electric transfer recording device generates heat in the immediate vicinity of the ink layer 13, so that the generated heat is efficiently transmitted to the ink. In addition, since thermal transfer recording devices use a thermal head, care must be taken to prevent heat accumulation in the thermal head and thermal damage to the thermal head, whereas with electrical transfer recording devices, the recording head does not generate heat, so The heat accumulation is also small, and there is no fear that the recording head will be destroyed even if the recording energy becomes large.Therefore, the recording speed can be increased in the current transfer recording device compared to the thermal transfer recording device.

Furthermore, thermal transfer recording devices can record on plain paper, but the image quality deteriorates on paper with a rough surface, but electric transfer recording devices can generate a large amount of recording energy, so they use rough paper recording inks with a high melting point. High-speed recording is also possible.

As mentioned above, each of the three types of thermal recording devices has its own unique characteristics.The thermal recording device is a facsimile machine, the thermal transfer recording device is a word processor, and the electric transfer recording device is a high-speed rough paper printer. It is applied to fields that take advantage of However, as will be explained below, in some cases a single recording device may be required that combines the contradictory features of these thermal recording devices.

First, let's compare the recording costs per A4 sheet for each recording method. Thermal recording paper currently on the market costs about 10 yen, and thermal transfer recording paper costs about 3 yen per character.
It costs about 7 to 8 sen per character in an electric transfer recording device.

Therefore, when recording more than about 300 characters per A4 sheet with a thermal transfer recording device, and approximately 150 characters or more with an electric transfer recording device, the recording cost per sheet becomes higher than the recording cost using thermal paper.

If you want to record beautiful characters with thermal transfer recording paper, you need to use special paper with a smooth surface (this costs around 5 yen), and considering this, even a thermal transfer recording device can record about 150 characters or more. In some cases, the cost is higher than that of thermal recording. However, thermal recording paper cannot be stored for long periods at room temperature, so it is not suitable for recording documents that will be kept for a long time. However, recently there are copying services that cost about 10 yen, so by copying text printed on thermal recording paper, it is possible to preserve it for a long time.

Considering all of these things, it costs about 500 per A4 sheet.
When recording more than 1 character, thermal recording is more advantageous, and when less than that, thermal transfer recording and electric transfer recording are more advantageous in terms of recording cost.

If we consider only the recording cost, we will get the above result,
Recently, the quality of characters has also been attracting attention.

Since thermal transfer recording devices and electrical transfer recording devices use ink, they can record beautiful characters with strong contrast compared to when thermal recording paper is used.

Furthermore, in order to record beautiful characters regardless of the type of recording paper, an electric transfer recording device is superior to a thermal transfer recording device, and moreover, it can record at high speed.

From the above, it can be said that the ideal situation is to be able to change the recording method depending on the purpose of use.

A portable word processor can be considered as an example where one recording device is used for various purposes.

It may be used for various personal purposes, and the way it is used varies depending on the person using it. As mentioned above, about 50
When recording sentences of 0 characters or less (for example, general notices, etc.), it is more advantageous in terms of recording cost to use a thermal transfer recording device or an electric transfer recording device. . On the other hand, technical and specialized texts such as various papers and reports are usually 500 characters or more per A4 sheet, and in this case thermal recording is more advantageous. Considering that approximately 1,600 characters can be recorded on one A4 sheet, it is approximately 1/3 faster to use thermal recording.
Recording costs will be lower.

Portable word processors currently on the market,
Most of the time, thermal transfer recording devices are used. Since a thermal transfer recording device uses a thermal head, it can also be used for thermal recording without using an ink ribbon. Therefore, for example, when considering recording costs, it is possible to switch between thermal recording and thermal transfer recording depending on the number of characters to be recorded. However, it is impossible to record beautiful characters on general plain paper (such as PPC paper) or rough paper (such as bond paper) that has a rough surface. Conversely, if an electric transfer recording device is used as a word processor recording device, it is possible to record on paper with a rough surface, but the structure of the recording head is different, so it cannot be used in combination with a thermal transfer recording device or a thermal recording device. This makes it impossible to record on thermal paper, which has low recording costs.

(Problem 8 to be solved by the invention) As mentioned above, the thermal recording method, the thermal transfer recording method, and the electrical transfer recording method each have their advantages and disadvantages, and one of them is optimal depending on the application, but the conventional technology It was not possible to select any one recording method using the same device.

The present invention provides a thermal recording head that can be applied to any recording method, such as a thermal recording method, a thermal transfer recording method, or an electric transfer recording method, depending on the usage conditions, in a recording device such as a word processor that has a wide variety of purposes and usage modes, and It is an object of the present invention to provide a thermal recording device that can arbitrarily select any of these three recording methods using a recording head.

[Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the thermal recording head of the present invention includes a heating resistor layer used in a thermal recording method and a thermal transfer recording method on a substrate, and a heating resistor layer used in a thermal recording method and a thermal transfer recording method, and A common electrode and a plurality of individual electrodes are formed in contact with the heat generating resistor layer, a heat generating area between the common electrode and the individual electrodes of the heat generating resistor layer is covered with a wear-resistant layer, and at least one of the common electrode and the individual electrodes is formed. A feature is that the common electrode and the individual electrodes can be used in all recording methods by exposing the portion of the heating resistor layer near the heating area.

Further, the thermal recording device of the present invention uses the above-mentioned thermal recording head, and the recording medium or ink carrier is coated with a wear-resistant layer and exposed portions of the common electrode and individual electrodes, that is, portions near the heat-generating region of the heat-generating resistor layer. , and recording is performed by any recording method selected from among a thermal recording method, a thermal transfer recording method, and an electric transfer recording method.

(Function) In the thermal recording head of the present invention, the portion of the heating resistor layer between the common electrode and the individual electrodes becomes the heating area, and in the case of a thermal recording method, the wear-resistant layer on the heating area In the case of a thermal transfer recording method, the abrasion resistant layer is pressed against a recording medium via a thermal transfer ink ribbon serving as an ink carrier.

On the other hand, in the case of the current transfer recording method, the wear-resistant layer, the common electrode, and the individual electrodes near the exposed heat-generating regions are pressed against the recording medium via the current transfer ink ribbon, which is an ink carrier. The individual electrodes are used as recording electrodes and the common electrode as return electrode.

In this way, a single thermal recording device using a common thermal recording head can selectively perform recording using each of the recording methods of thermal recording, thermal transfer recording, and electrical transfer recording. Therefore, for example, recording costs can be reduced by using a thermal recording method when recording a text with a large number of characters, and by using a thermal transfer recording device when recording a text with a small number of characters. Furthermore, if it is desired to record characters with high quality and high speed on rough vapor having a rough surface, an electric transfer recording method may be used. .

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of a thermal recording head used in three recording methods of the present invention, in which (a) is a perspective view of the main part, and (b) is a view taken along A-A in (a). It is an arrow sectional view. As shown in the figure, a heating resistor layer 22 is formed on an insulating substrate 20 with excellent heat resistance such as a ceramic substrate with a glaze layer 21 made of glass or the like serving as a heat storage layer interposed therebetween. A common electrode 23 and a plurality of individual electrodes 24 on the layer 22
is formed.

Then, the common electrode 23 and the individual electrodes 2 of the heating resistor layer 22
A wear-resistant layer 25 is formed on the portion between the common electrode 23 and the individual electrode 24 (heat-generating region), and a wear-resistant layer 26 is also formed on the portions of the common electrode 23 and the individual electrodes 24 other than the portions 28° 29 near the heat-generating region.
．． 27 is formed. For example, a 5in2 film is used for the wear-resistant layers 25, 26, and 27. The heating resistor layer 22 is made of the same material as that of a conventional thermal head.

In conventional thermal heads, a wear-resistant layer is formed on the entire surface of the part that contacts the ink ribbon, but in this thermal recording head, the wear-resistant layer is 25 and 2.
It is cut at the part between 6.27, and the common electrode 23 and individual electrode 24 are exposed at this part as shown in 28.29.
The major difference is that it comes into direct contact with thermal paper or ink ribbon. For this reason, the material of the electrodes 23 and 24 is different from that of conventional thermal heads, and is made of a metal with high wear resistance, such as tungsten.

FIG. 2 shows an embodiment of the thermal recording device of the present invention using the thermal recording head shown in FIG. 1, and is an example applied to a serial printer. Note that since the structure of the printer is similar to that of a normal serial printer, only the vicinity of the recording section is schematically shown in the figure.

In FIG. 2, a carriage 30 moving along an axis 31 carries the thermal recording head 32 shown in FIG.

Further, an ink ribbon 34 for thermal transfer or electrical transfer is housed in an ink ribbon cassette 33 on the carriage 3o. The ink ribbon 34 is taken up by a pair of take-up rollers (not shown), and the ink ribbon 34 is let out in the direction of arrow A from a payout reel 35a. The ink ribbon 34 fed out from the feeding reel 35a is wound up in the direction of arrow B on the take-up reel 35b.

When the carriage 30 moves in the direction of arrow C, the recording paper 36
When an image is recorded thereon and the carriage 30 moves in the opposite direction of arrow C, no image is recorded and the platen 37 transports the recording paper 36 by the required amount. The thermal recording head 32 prints the ink ribbon 34 and the recording paper 3 before starting recording.
6 and is pressed against the platen 27, and the pressure contact is released after recording is completed.

Next, the operation of this embodiment will be explained with reference to FIG. FIGS. 3(a) and 3(b) show current flows in thermal transfer recording and electrical transfer recording, respectively.

First, in the case of thermal transfer recording shown in FIG. 3(a),
An ink ribbon 34 having an ink layer 38 coated on a base film 37 is used, and the ink ribbon 34 is pressed against a recording paper 36 using a thermal recording pad 32. At this time, common electrode 2
When a voltage is applied between the common electrode 23 and the individual electrode 24, for example, as shown by the arrow in the figure, the common electrode 23 (or the individual electrode 24
), a current flows toward the individual electrodes (or the common electrode 23) via the heating resistor layer 22. Joule heat generated when current flows through the heating resistor layer 22 causes the ink ribbon 3 to
By heating the ink layer 38 coated on the recording paper 4, the ink in the ink layer 38 is transferred to the recording paper 36 to form an image.

On the other hand, in the case of electrical transfer recording shown in FIG. 3(b), an ink ribbon 34' having an ink layer 38' coated on a resistive base film 37' is used. An ink ribbon 34' is placed on the recording paper 36.

The thermal recording head 32 is pressed into contact with the common electrode 23 and the individual electrodes 2.
4, current flows through two types of paths: solid arrows and broken arrows.

That is, in the case of electrical transfer recording, the ink ribbon 34'
Because the base film 37' of the base film 37' is resistive, current flows into the base film 37', for example from the exposed portion 28 of the common electrode 23 that is in direct contact with the base film 37', and the current flows into the base film 37' of the individual electrodes 24 of the base film 37'. A current path is formed in which current flows into the individual electrode 24 from the portion that is in contact with the exposed portion 29 . In this way, the ink layer 38' is heated by Joule heat generated when current flows through the resistive base film 37', and the ink in the ink layer 38' is transferred to the recording paper 26 to form an image.

Note that the resistance value of the resistive base film 37' is designed to be smaller than the resistance value of the heating resistor layer 22 of the thermal recording head 32. Therefore, most of the current flowing between the electrodes 23 and 24 flows through the resistive base film 37' as indicated by the solid arrow in the figure, but some of the current flows through the heating resistor layer 22.
Current also flows along the path shown by the dashed arrow.

As described above, the thermal recording head of the present invention can be used in the same way as a conventional thermal head in the case of thermal recording or thermal transfer recording, as shown in FIG. 3(a), and can also be used in the case of current transfer recording. can be used in the same way as a conventional current transfer recording head, as shown in FIG. 3(b). For this reason,
With one recording device, it becomes possible to arbitrarily select each recording method of thermal recording, thermal transfer recording, and electrical transfer recording according to recording conditions and the like.

FIG. 4 shows a specific example of the drive circuit for the thermal recording device of the present invention. Generally, conventional thermal heads for thermal recording and thermal transfer recording are driven by a constant voltage drive circuit, and current transfer recording heads are driven by a constant current drive circuit. In current transfer recording, when high-speed recording is performed, the contact resistance between the ink ribbon and the electrode may change significantly, so constant voltage driving causes the amount of heat generated in the resistive base film to change. Therefore, FIG. 4 shows an example of constant current drive.

In FIG. 4, the part surrounded by a broken line is a constant current drive circuit corresponding to one individual electrode 24, and FIG. 4(a) is an equivalent circuit for thermal recording and thermal transfer recording. The constant current drive circuit includes a transistor 40 for driving the individual electrode 24, and a current monitor resistor 41 (resistance value r.)
41, an operational amplifier 42, a switching element 43, and a reference voltage source 44 (assumed to have a voltage value of V). Further, the common electrode 23 is connected to a drive voltage source 45 (voltage value VD), and the heating resistor layer 22
is connected to the individual electrode 24 via a resistor R8.

The switching element 43 is normally connected to the contact (2) side, and no current flows through the individual electrodes 24. The switching element 43 is connected to the contact ■ side for only the time period during which current is desired to flow through the individual electrode 24, and the reference voltage V is applied to the non-inverting input terminal of the operational amplifier 42.

When applied, a current flows through the individual electrodes 24.

The operational amplifier 42 has a reference voltage V in which the voltage at the inverting input terminal is applied to the non-inverting terminal. The current flowing through the current monitor resistor 41 is controlled so that it becomes equal to . That is, Vo
mr. The current I is -10. flows to the monitor resistor 41. Since the collector current of the transistor 40 is approximately equal to the emitter current, I is also applied to the individual electrode 23, that is, the heating resistor layer 22. A current will flow.

FIG. 4(b) shows an equivalent circuit when an ink ribbon 34' for electrical transfer is used. The function of the constant current drive circuit is exactly the same, but between the common electrode 23 and the individual electrodes 24, in addition to the resistance R8 of the heating resistor layer 22, a resistance R1 of the resistive base film 37' is connected in parallel with Ro. They are different in what they contain.

In this case, base/$ lightning voltage■. When , the monitor resistor 41 is I. A current of -Vo/rO flows, and this current I. also flows through the parallel resistances of Ro and R1, so R8, R
The current flowing through 1 has a value divided by these resistors. Therefore, the ink ribbon 34' for electrical transfer recording has
Even if a constant current drive circuit is used, constant current drive is not necessarily achieved, but it has the advantage that excessive current can be prevented.

Here, the resistance R1 of the resistive base film 37' is smaller than the resistance R8 of the heating resistor layer 22. Therefore, more current flows through the resistive base film 37' than through the heating resistor layer 22. A major feature of current transfer recording is that heat is generated in the immediate vicinity of the ink layer 38', so heat is efficiently transferred to the ink layer 38', and high-speed recording can be achieved.However, due to the relationship R,>R, Efficient current recording can be achieved by controlling the respective resistance values so as to achieve the following.

In addition, in FIG. 4, the voltage V of the reference voltage source 44.

is variable, because the optimum current value is different for thermal recording, thermal transfer recording, and electrical transfer recording. This is because the sensitivity and recording speed of thermal paper, thermal transfer ink ribbon, and current recording ink ribbon are different.

Further, in FIG. 4, the voltage VD of the drive voltage source 45 is also variable. This is because when a current with an optimum current value is passed for each recording method, the loss in the drive transistor 40 may increase if the load resistance of the circuit changes. For example, in Fig. 4(a), R8-1 is set to Ω, and the drive current is 30tpA.
is required, the drive voltage VD is approximately 3
0V is required. However, in the case of Figure 4(b),
Assuming that the load resistance R6/R is 500Ω and the current is required to be 30mA, the drive voltage VD is 1
5V is sufficient.

In this way, if the drive voltage VD is kept constant at 30V, which is required in the case of FIG. 4(a), in the case of FIG. 4(b), a voltage of 15V is consumed as collector loss in the transistor 40. It turns out. This loss is converted into heat, making it difficult to integrate it into an IC. Therefore, as mentioned above, by making the drive voltage VD variable, and lowering VD to about 15V in the case of FIG. 4(b), and using the drive transistor 40 in a nearly saturated region, this loss can be reduced. Prevent this from happening.

Note that as a method of making the reference voltage V0 and drive voltage VD variable, for example, a D/A converter is used as the reference voltage source 44 and the drive voltage source 45, and the manual value of the D/A converter is adjusted as appropriate by the CPU or the like. By changing the voltage, a method can be used to extract the necessary analog voltage.

Although a constant current drive circuit is shown in FIG. 4, it is of course possible to use a constant voltage drive circuit without departing from the spirit of the present invention.

In addition, in all the above embodiments, from the common electrode 23 to the individual electrodes 2
Although we have explained an example in which the current is passed in the direction 4, the same effect can be obtained even if the current is passed in the opposite direction.

Further, in FIG. 4, the common electrode 23 side is set to the 10 power supply and the individual electrode 24 side is set to the ground potential, but the same effect can be obtained even if the common electrode 23 side is set to the ground potential and the individual electrode 24 side is set to the -potential.

Note that the three recording methods of thermal recording, thermal transfer recording, and electrical transfer recording may be selectively switched by a mode changeover switch provided on the printer or a command from a host CPU connected to the outside. .

Furthermore, it is also possible to use a method in which the ink ribbon cassette or the like is devised so that when a cassette is installed, it can be determined which ribbon cassette it is by reading a sensor or the like.

In addition, in the thermal recording apparatus of the present invention, in order to appropriately select the recording method, it is necessary to check whether the ink ribbon 34 for thermal transfer or the ink ribbon 34' for electrical transfer is set as the ink ribbon. It is necessary to know exactly whether or not there is one immediately before recording.

By using the constant current drive circuit configured as shown in FIG. 4, it is also possible to know what kind of ink ribbon is set. Specifically, with the thermal recording head 32 pressed against the ink ribbon, a known minute current that does not result in recording is passed through each individual electrode 24, and the common electrode 23 is
By examining the potential difference generated between the ink ribbon and the individual electrodes 24, the type of ink ribbon, that is, the recording method can be identified.

For example, when a current is applied to a thermal recording device without pressing the head 32 against the ink ribbon, a certain potential difference V1 is generated between the common electrode 23 and the individual electrode 24, and when the thermal recording head 32 is pressed, a potential difference V2 is generated. Suppose that a potential difference occurs. At this time, if it is V12V2, either the thermal transfer ink ribbon 34 is set and the thermal transfer recording method is selected, or the ink ribbon is not set and only the recording paper (thermal paper is set and the thermal recording method is selected). It turns out that.

Moreover, if V,>V2, the ink ribbon 3 for electrical transfer
4' is set, which means that the energization recording method has been selected.

Next, other embodiments of the thermal recording head according to the present invention will be described with reference to FIGS. 5 to 8.

The thermal recording head shown in FIG. 2 corresponds to a so-called planar type thermal head.

The flat type has the advantage of having a simple structure and being easy to manufacture, but because the area in which the recording paper and ink ribbon come into close contact with the thermal recording head is large, if you try to increase the contact pressure, you will be pressed with a large force. There must be.

To solve this problem, conventional thermal heads
So-called partial glaze types may be used.

FIG. 5 shows another embodiment of the thermal recording head of the present invention, in which the thermal head portion has a structure corresponding to a partial glaze type. That is, this thermal recording head has a substrate 20
A glaze layer 21 is formed only on the upper part, and a heating resistor layer 22, a common electrode 23, and an individual electrode 24 are formed thereon. An insulating wear-resistant layer 25 is embedded between the individual electrodes 23 and the common electrode 24.

In a thermal recording head having such a structure, as well as the one shown in FIG. In addition to this, if a current flows and an ink ribbon 34' for current transfer is used, the common electrode 23
A current path is formed: - resistive base film 37' - individual electrodes 24. Also in this example, since the individual electrodes 23 and the common electrode 24 slide in direct contact with the ink ribbon, it is necessary to use tungsten or the like with high wear resistance.

With the partial glaze structure shown in Figure 5, the contact area between the recording paper and ink ribbon and the thermal recording head is smaller than that of a flat head, so even if a small force is applied, the contact pressure between the ink ribbon and the recording paper can be reduced. It can be made larger, and it is possible to record beautiful images even when using paper with a somewhat rough surface. In addition, partial glaze type recording heads are also better in terms of image quality and recording speed, especially in the case of thermal transfer recording or electrical transfer recording using sublimation type ink, which requires a large amount of pressure between the ink ribbon and the recording paper. It is advantageous in this respect.

In addition to the thermal recording head of the embodiment shown in FIG. 5, the thermal recording head shown in FIG. The wear-resistant layer 26 is placed so that the portion 28° 29 near the heat generating area is exposed.
．． 27 was formed.

The thermal recording head shown in FIG. 5 also basically has an electrode 23.2.
4 and the ink ribbon only in the vicinity of the convex part, but due to mechanical inconvenience, the ink ribbon may sag or flap, causing the ink ribbon to come into contact with unnecessary electrodes 23 and 24. be. This is fine in the case of the ink ribbon 34 for thermal transfer, but in the case of the ink ribbon 34' for electrical transfer, current flows from the contact area between the ink ribbon 34' and the electrodes 23 and 24.
When the size of the image point changes, or when it touches or separates, a discharge occurs, and this discharge causes the electrode 23.
24 may be destroyed by discharge. If a wear-resistant layer 26, 27 is newly formed as shown in FIG. 6, and the contact between the ink ribbon and the electrode 23, 24 is limited to only the convex portion where the glaze layer 21 is formed, such a situation can be avoided. No inconvenience will occur.

In the thermal recording head shown in FIGS. 1, 5, and 6,
Considering the case where it is used for electrical transfer recording, the electrode 23.2
4. Metals with high wear resistance have been used. However, metals with high wear resistance, such as tungsten and cobalt,
Nickel, other metals, and their alloys are difficult to process and are expensive, so if they are used in large quantities, the unit price of the recording head will increase. The thermal recording head shown in FIG. 7 is an improvement on this point.

In the thermal recording head shown in FIG. 7, a glaze layer 21 is formed on a substrate 20, and a heating resistor layer 22, a common electrode 3, and individual electrodes 24 are formed on the glaze layer 21. The formation process up to this point may be exactly the same as the thin film process for making a normal thermal head, and the common electrode 23 and the individual electrodes 24 may be thin film electrodes made of a highly conductive metal such as copper. As can be seen from FIG. 7, the electrodes 23 and 24 do not directly contact the ink ribbon, but the electrodes 2B' and 24' formed on the electrodes 23 and 24 contact the ink ribbon. This is because it is an exposed part.

To explain the specific manufacturing process, after the common electrode 23 and the individual electrodes 24 are formed, a mask is applied, a highly wear-resistant metal is applied only to the necessary parts by plating, etc., and then the ink ribbon is coated. Exposed portions 23' and 24' of the common electrode 23 and individual electrodes 24, which serve as contact portions, are formed.

Finally, a wear-resistant layer 26 such as a SiO□ film that also serves as insulation, .
By forming 27, the thermal recording head shown in FIG. 7 can be realized.

In this way, the thermal recording head shown in FIG.
3 and the individual electrodes 24, only the exposed parts 23' and 24' which are in contact with the ink ribbon are made of wear-resistant electrode materials such as metals and alloys, and the manufacturing process is simple. Moreover, the cost is greatly reduced.

Figure 7 shows an example of a flat type thermal recording head.
As shown in FIG. 8, a similar configuration can be applied to a partial glaze type thermal recording head.

[Effects of the Invention] As explained above, according to the present invention, in a recording device such as a word processor, which is used for a wide variety of purposes, a recording device selected from a thermal recording method, a thermal transfer recording method, and an electric transfer recording method according to the usage conditions can be used. Any recording method can be used.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are a perspective view and a sectional view taken along the line A-A of the thermal recording head of the present invention, and FIG. 2 is a perspective view of an embodiment of the thermal recording device of the present invention. Figure, Figure 3(a) (
b) is a cross-sectional view for explaining the operation of the thermal recording head in FIG. 1, and FIGS. 4(a) and 4(b) are diagrams showing the drive circuit for driving the recording head of the present invention and during thermal transfer recording and current transfer recording. Figures 5, 6, 7 and 8 show the equivalent circuits of
The figure is a sectional view showing another embodiment of the thermal recording head of the present invention.
FIG. 9 is an explanatory diagram of a conventional thermal transfer recording device, FIG. 10 is an explanatory diagram of a conventional thermal transfer recording device, and FIG. 11 is an explanatory diagram of a conventional electrical transfer recording device. 20...Substrate 21...Glaze layer 22...Heating resistor layer 23...Common electrode 24...Individual electrode 25.26.27...Wear-resistant layer 2B, 24.28.29. ...Exposed portion 30...Carriage 32...Thermal recording head 34...Ink ribbon for thermal transfer 34'...Ink ribbon for electrical transfer 36...Recording 37...Base film 37'...・Resistive base film 38...Ink layer 38'...Ink layer

Claims (3)

[Claims] (1) In a thermal recording head comprising a heating resistor layer on a substrate, and a common electrode and a plurality of individual electrodes in contact with the heating resistor layer, the common electrode and the individual electrodes of the heating resistor layer 1. A thermal recording head characterized in that a heat generating area between the common electrodes and the individual electrodes is covered with a wear-resistant layer, and at least a portion of the common electrode and the individual electrodes near the heat generating area is exposed. (2) Using the thermal recording head according to claim 1, a recording medium or an ink carrier is brought into contact with the wear-resistant layer and portions of the common electrode and the individual electrodes near the heat-generating regions, and a thermal recording method or a thermal transfer recording method is used. A thermal recording device characterized in that it performs recording by any recording method selected from among the current transfer recording methods. (3) By detecting the potential difference that occurs between the common electrode and the individual electrodes when a known current is passed through the thermal recording head through the common electrode and the individual electrodes, it is determined whether the selected recording method is a thermal recording method or 3. The thermal recording apparatus according to claim 2, further comprising identification means for identifying whether the recording method is a thermal transfer recording method or an electric transfer recording method.