JPS61219102A - Thermal recording head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal recording head used in a recording method that performs recording using thermal energy.

[Conventional technology]

Traditionally, recording methods that use thermal energy to record have the advantage of being non-impact and therefore produce extremely little noise during recording, and in recent years have attracted increasing attention because they can also be used in color. It's coming.

In such a recording method, recorded information is transmitted in the form of an electrical signal to a thermal recording head, that is, an electrothermal conversion element. The electro-thermal conversion element used includes a heat generating resistance layer formed on a base and at least one pair of electrodes connected to the heat generating resistance layer.

Here, the term "substrate" refers to one that supports a heat generating resistive layer, and the substrate is simply a support with appropriate layers formed thereon, if necessary. Since thermal recording heads are generally relatively small, their heating resistance layers are of a thin film type, a thick film type, or a semiconductor type. especially,
Thin-film types consume less power than other types and have relatively good thermal responsiveness, so they are preferred as components of thermal recording heads, and their use is gradually increasing. .

Therefore, the performance required of the heat generating resistive layer of a thermal recording head is good responsiveness of heat generation to a predetermined electric signal, good thermal conductivity, and good heat resistance against its own heat generation. and that various types of durability (for example, durability against thermal history) are good. Furthermore, when the thermal recording head is used in pressure contact with thermal paper or thermal transfer ink ribbon, it is required that the coefficient of friction with these is small.

However, it cannot be said that the above performance is necessarily satisfactory in the heat generating resistive layer of the conventionally used thermal recording head, and further improvement of the characteristics is desired.

Furthermore, in conventional thermal recording heads, a wear-resistant layer is provided on the surface of the heat-generating resistor layer in order to improve wear resistance, but this comes at the expense of thermal responsiveness.

In addition, with conventional thermal recording heads, when recording on a recording medium with a rough surface, such as paper, it is necessary to press the recording medium more firmly in order to record in a perfect dot shape, resulting in faster wear. There is a desire for further improvement in performance.

[Object of the invention] In view of the above-mentioned prior art, one of the objects of the present invention
One object of the present invention is to provide a thermal recording head having a heat generating resistive layer with improved thermal responsiveness.

Another object of the present invention is to provide a thermal recording head having a heating resistance layer with improved thermal conductivity.

Still another object of the present invention is to provide a thermal recording head having a heating resistance layer with improved heat resistance.

Another object of the present invention is to provide a thermal recording head having a heat generating resistive layer with improved durability.

Another object of the present invention is to provide a thermal recording head having a heating resistance layer with improved wear resistance.

Still another object of the present invention is to provide a thermal recording head having a heat generating resistance layer with a small coefficient of friction.

SUMMARY OF THE INVENTION The above objects are achieved by a novel thermal recording head according to the present invention.

In the thermal recording head of the present invention, one heat generating resistive layer is made of an amorphous material containing carbon atoms as a matrix and hydrogen atoms, and the hydrogen atoms are unevenly distributed in the thickness direction of the heat generating resistive layer. It is characterized by

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 is a partial plan view showing the structure of an embodiment of the thermal recording head of the present invention, and FIG. 2 is a sectional view taken along the line 1--2.

In the figure, 2 is a support (substrate here), 4 is a heating resistance layer, and 6.7 is a pair of electrodes. 1st
As shown in the figure, a plurality of pairs of one heating resistor layer 4 and a pair of electrodes 6.7 connected to the heating resistor layer 4 are provided, thereby forming a dot-shaped effective heating portion 8.8'. ,8″,
- The groups Φ will be arranged on a straight line at predetermined intervals. When the thermal recording head is in use, the heat generating resistive layer 4 side is brought into pressure contact with thermal paper or thermal transfer ink ribbon, etc., and is moved relative to the thermal paper or thermal transfer ink ribbon in the -■ direction. When each fever occurs! 8.8', 8'', heat generating resistance layer 4 that constitutes the pot
Electric signals, which are recorded information, are timely applied to each electrode through the electrodes 6 and 7, and each heat generating part generates heat based on this.
Recording using a heat sensitive method or a thermal transfer method is performed using the ripe energy at this time.

In the present invention, there is no particular restriction on the material of the support 2, but in practice it has good adhesion to the heating resistor layer 4 and the electrodes 6 and 7 formed on its surface. It is preferable to use a material that has good durability against the heat generated during the formation of 6.7 and the heat generated by the heat generating resistor layer 4 during use.

The support 2 also has a heating resistance layer 4 formed on its surface.
It is preferable to have an electrical resistance larger than that of the support 2. Furthermore, a material is selected for the support 2 that has thermal conductivity that allows necessary and sufficient thermal energy to be applied to the recording medium side and that does not deteriorate responsiveness to electrical input. .

Examples of the support 2 used in the present invention include those made of inorganic materials such as glass, ceramics, and silicon, and those made of organic materials such as polyamide resin and polyimide resin.

In the present invention, the first heating resistance layer 4 is made of an amorphous material having carbon atoms as its base material and containing hydrogen atoms.

The content of hydrogen atoms in the heat generating resistance layer 4 is appropriately selected so as to obtain desired characteristics, and is preferably o, o.
oot~30 at%, more preferably 0.000
The content is 5 to 20 atom %, preferably 0.001 to 10 atom %.

In the present invention, the distribution of hydrogen atoms in one heating resistance layer 4 is non-uniform in the film thickness direction.

The content of hydrogen atoms in the heating resistor layer 4 in the thickness direction may be such that the content gradually increases from the base 2 side to the surface side, or may be such that the content decreases conversely. Furthermore, the hydrogen atom content change may have a maximum value or a minimum value in the resistance layer 4. These hydrogen atom content changes in the film thickness direction in the heat generating resistor R4 may have desired characteristics. It is selected as appropriate to obtain the desired results.

3 to 8 show specific examples of changes in the hydrogen atom content in the film thickness direction in the heat generating resistive layer 4 of the yet-to-be invented thermal recording head. In these figures, the vertical axis is the base 2 and represents the distance T from the interface in the film thickness direction, and t represents the film thickness of the heating resistor layer 4.

Further, the horizontal axis represents the hydrogen atom content C. In each figure, the scales of the vertical axis T and the horizontal axis C are not necessarily uniform, but are varied to bring out the characteristics of each figure.

Therefore, in actual application, various distributions are used for each diagram based on the differences in specific numerical values.

In the thermal recording head of the present invention, the heating resistor layer 4 made of an amorphous material (hereinafter sometimes abbreviated as ra-C:HJ) made of carbon as a matrix and containing hydrogen atoms can be formed by, for example, a glow discharge method. It is formed by a vacuum deposition method such as a plasma CVD method or a sputtering method.

For example, to form the resistance layer 4 made of a-C:H by the glow discharge method, the base 2 is basically placed in a deposition chamber under reduced pressure, and carbon atoms (C) are supplied into the deposition chamber. A raw material gas for supplying C to be obtained and a raw material gas for supplying H that can supply hydrogen atoms (H) are introduced, and at this time, high frequency or micro wave is applied in the deposition chamber while changing the amount of the raw material gas for H supply. A glow discharge may be generated using waves to form a layer consisting of a-C:H on the surface of the substrate 2.

In addition, in order to form the resistance layer 4 made of a-CsH by sputtering, the base 2 is basically placed in a deposition chamber under reduced pressure, and inert gas such as Ar, He, etc. When sputtering a target composed of C in an atmosphere of a mixed gas based on these gases, a raw material gas for H supply is introduced into the deposition chamber,
At this time, the amount introduced may be changed.

In the above method, as the raw material gas for supplying C and the raw material gas for supplying H, in addition to those in a gaseous state at room temperature and normal pressure, substances that can be gasified under reduced pressure can be used.

Examples of raw materials for C supply include saturated hydrocarbons having 1 to 5 carbon atoms, ethylene hydrocarbons having 2 to 5 carbon atoms, acetylenic hydrocarbons having 2 to 4 carbon atoms, aromatic hydrocarbons, etc. The saturated hydrocarbons include methane (CH4), ethane (C2Ha), propane (C3Ha), n-buta7 (n-C4H10), pentane (C5H12),
Ethylene hydrocarbons include ethylene (C2H4),
Propylene (C3Ha), butene-1 (C4H8)
, butene-2 (C4H8), inbutylene CC4
Examples of acetylene hydrocarbons include acetylene (C2H2), methylacetylene (03H4), and butyne (C4H6), and examples of aromatic hydrocarbons include benzene (C6Ha).

As a raw material for H supply, for example, hydrogen gas.

and hydrocarbons such as saturated hydrocarbons, ethylene hydrocarbons, acetylene hydrocarbons, and aromatic hydrocarbons, which are also the raw materials for supplying the above C.

These raw materials may be used alone or in combination.

In the heat generating resistance layer forming method as described above, in order to control the amount of hydrogen atoms contained in the formed resistance layer 4 and the characteristics of the resistance layer 4, it is necessary to control the substrate temperature, the supply amount of raw material gas, the discharge power, the deposition Set the indoor pressure etc. appropriately.

In particular, in order to obtain the heat generating resistor layer 4 in which hydrogen atoms are unevenly distributed in the film thickness direction of the present invention, it is preferable to change the amount of hydrogen atoms introduced into the deposition chamber over time, for example, by controlling a valve. .

The substrate temperature is preferably selected from 20 to 1500°C, more preferably 30 to 1200°C, and optimally 50 to 1100°C.

The supply amount of the raw material gas is determined as appropriate depending on the desired performance of the heating resistance layer and the desired film formation rate.

Discharge power is preferably 0.001 to 20W/crn'
, more preferably 0,01-15W/crn', optimally 0.05-LOW/crn'.

The pressure inside the deposition chamber is preferably 10''4 to 10 Torr.
r, more preferably 10''2 to 5 Torr.

The resistive layer of the thermal recording head of the present invention obtained using the heat generating resistive layer forming method as described above has properties close to those of diamond. That is, for example, Vickers hardness taoo to 5ooo
, thermal conductivity 0.3~2cal/cmesece"c, resistivity 105~1011Ω・cm, thermal expansion coefficient 2X10-5
~10''''67°C, coefficient of friction 0.15~0.25, density t, S~3.0. Furthermore, since the resistance layer of the thermal recording head of the present invention contains hydrogen atoms, it is easy to form an I& film.

In the thermal recording head of the present invention, the resistance layer 4 has particularly good abrasion resistance, so the resistance layer can be made extremely thin, and a special abrasion resistant layer is not required, resulting in extremely good thermal response. you can get something.

However, it goes without saying that a layer having appropriate protection and other functions may be provided on the heating resistance layer 4 of the thermal recording head of the present invention. For example, by providing a protective layer, even more durability can be achieved. You can make improvements.

In the embodiments described above, an example is shown in which the heating resistance layer and the electrode are provided on the substrate in this order, but in the thermal recording head of the present invention, the electrode and the heating resistance layer may be provided on the substrate in this order. FIG. 9 is a partial sectional view of such a thermal recording head. In FIG. 0, 2 is a support (substrate here).
4 is a heating resistance layer, and 6.7 is a pair of electrodes.

In this case, since the more durable heat-generating resistive layer is placed on the recording medium side, extremely excellent thermal recording can be achieved even without the provision of a wear-resistant layer.

Note that in one or more embodiments, the substrate is simply a support 2.
However, the substrate in the present invention may be a composite body.
As shown in the figure, the base 2 is made of a composite of a support 2a and a surface layer 2b, and the support 2a includes, for example, the first layer described above.
The support material explained in connection with the figure or even metal can be used, and as the surface layer 2b, a material with better adhesion to the resistance layer 4 formed thereon can be used. The layer 2b is made of, for example, an amorphous material having carbon atoms as a matrix, a conventionally known oxide, or the like. Such a surface layer 2b can be obtained by depositing appropriate raw materials on the support za by a method similar to the above-mentioned method for forming the heating resistor layer. Further, the first surface layer 2b may be a normal glassy glaze layer.

The electrodes 6 and 7 in the thermal recording head of the present invention may be made of materials having a predetermined conductivity, such as Au, Cu,
Made of metal such as AI, Ag, and Ni.

Next, the outline of the method for manufacturing the thermal recording head of the present invention will be explained.

FIG. 11 is a diagram showing an example of an apparatus used when forming a heating resistance layer on the surface of a substrate. 1101 is a deposition chamber, 1102 to 1106 are gas cylinders, and 110
7-11! l is a mass flow controller, 111
2-111B are inflow valves, 1117-1121
is an outflow valve, 1122-1126 is a gas cylinder valve, 1127-1131 is an outlet pressure gauge, 1132 is an auxiliary valve, 1133 is a lever, 1134 is a main valve, and 1135 is a leak valve. , 1136 is a vacuum gauge, and 1137
is the base material of the thermal head to be manufactured, and 113
8 is a heater, 1139 is a base support means, 1
140 is a high voltage power supply, 1141 is an electrode, 1
142 is a shutter. Note that 1142-1 is a target attached to the electrode 1141 when performing the sputtering method.

For example, 1102 contains CH4 gas (purity 99°996
above) is sealed, and 1103 has C2H6 gas (
Purity: 99.9% or higher) is sealed. Before the gas in these cylinders flows into the deposition chamber 1101, each gas cylinder 1102~! lO6 valves 1122-112
6 and leak valve 1135 are closed, and inlet valves 1112-1116. After confirming that the outflow valves 1117 to 1121 and the auxiliary valve 1132 are open, first open the main valve 1134 to evacuate the deposition chamber 1101 and gas piping. When the temperature reaches 10-”Torr, the auxiliary valve 1132 and the inflow valve 1112 are closed.
-1116 and outlet valves 1117-1121 are closed. Thereafter, a valve of a gas pipe connected to a cylinder of gas to be introduced into the deposition chamber 1101 is opened to introduce a desired gas into the deposition chamber 1101.

Next, an example of the procedure for forming the resistive layer of the thermal recording head of the present invention by the glow discharge method using the above-described apparatus will be described. Open the valve 1122 and open the gas cylinder 11.
CH, gas flows out from 02, outlet pressure gauge 1127
Adjust the pressure to tkg/Cgo, then open the inlet valve 111
2 is gradually opened to allow inflow into the mass flow controller 1107, and then the outflow valve 1117. The auxiliary pulp 1132 is gradually opened to supply CH and gas to the deposition chamber 110.
Introduced within 1. At this time, adjust the mass flow controller 1107 so that the flow rate of CH4 gas becomes the desired value,
Further, the opening degree of the main valve 1134 is adjusted while checking the reading of the vacuum gauge 1136 so that the pressure in the deposition chamber 1tot reaches a desired value.

Then, the substrate 1137 supported by the support means 1139 in the deposition chamber 1101 is heated by the heater 1138 so that the temperature reaches a desired temperature, and then the shutter 114 is heated.
2 is opened to generate glow discharge in the deposition chamber 1101. Then, the opening degree of the outflow valve 1117 is changed manually or by an external drive motor, etc., and the flow rate of CH4 gas is changed over time according to a pre-designed rate of change curve. The content rate of the film is changed in the film thickness direction.

Next, an example of the procedure for forming the resistive layer of the thermal recording head of the present invention by sputtering using the above-described apparatus will be described. On the electrode 1141 to which a high voltage is applied by the high voltage power supply 1140, there is a high purity graph eye)!
142-1 as a target, CH from gas cylinder 1102 in the same manner as in the glow discharge method.
4 gases are introduced into the deposition chamber ttot at a desired flow rate. The target 1142-1 is sputtered by opening the shutter 1142 and turning on the high voltage power supply 1140. At this time, the base 1137 is heated by the heater 1138.
As in the case of the glow discharge method, the deposition chamber 1101 is heated to a desired temperature and the pressure inside the deposition chamber 1101 is set to a desired value by adjusting the opening degree of the main valve 1134. Then, as in the case of the glow discharge method described above, the opening degree of the outflow valve 1117 is changed to change the flow rate of CH4 gas over time according to a pre-designed rate of change curve. The content of H atoms in the film is varied in the film thickness direction.

In the case of a thermal recording head as shown in FIGS. 1 and 2, the formation of the heat generating resistive layer on the substrate by the glow discharge method and sputtering method as described above is carried out over almost the entire surface of the substrate. Thereafter, by forming a conductive layer and etching the conductive layer and heat generating resistive layer using photolithography, a thermal recording head having a plurality of dot-shaped effective heat generating parts as shown in FIG. 1 can be obtained. .

Furthermore, in the case of a thermal recording head as shown in FIG.
After forming a conductive layer on a substrate in advance and etching the conductive layer using photolithography, a heat generating resistive layer is formed on the substrate by the glow discharge method and sputtering method as described above.

Specific examples of the thermal recording head of the present invention are shown below.

Example 1: A glaze layer was provided on a support made of an alumina ceramic plate as a base, and a heat generating resistor layer was formed on the surface of the base. The deposition of a heat generating resistor layer was shown in FIG. The method was carried out using a glow discharge method using a device similar to the one described above.

CH4 was used as a raw material gas. The conditions for deposition are the first
As per the table. During the deposition, the opening degree of the valve is continuously changed to change the flow rate of CB and gas.
A heating resistor layer having the thickness shown in the table was formed.

After forming an A1 layer on the formed resistance layer by electron beam evaporation, the A1 layer is formed by photolithography.
The layer was etched into the desired shape to form multiple pairs of electrodes.

Subsequently, predetermined portions of the resistive layer were removed by photolithography using an HF-based etching solution. still,
In this example, the size of the resistance layer between the electrode pair is 200 ILm x 300 km. In this example, the resistance layer formed between the electrode pair has a length of 7
A plurality of heating resistance elements were fabricated on the same substrate so that they were arranged in nine arrays.

The electrical resistance of each heating resistor element of the thus obtained thermal head was measured and found to be 90Ω.

Furthermore, an electrical pulse signal was input to each heating resistor element of the thermal head obtained in this example to measure the durability of the heating resistor element.

Note that the duty of the electrical pulse signal is 50%, and the applied voltage is 6.
■, Drive frequency 0.5kHz, 1. okHz, 2.0k
Hz.

As a result, in all cases of driving at different driving frequencies, the heating resistor element was not destroyed even when the electrical pulse signal input reached 1XloIO times, and its resistance value hardly changed.

Next, when printing characters with a composition of 5 dots horizontally x 7 dots vertically using thermal recording paper, the result was 2×109
Even after the characters were printed, no problems such as missing dots occurred in the recorded characters. Furthermore, it was found that when the thermal head of this example was used as a so-called thermal transfer type in which recording is performed on recording paper via a thermal transfer ink ribbon, it also had extremely excellent durability.

Furthermore, when recording was performed using so-called type paper with a rough surface as recording paper, the thermal head of this example had extremely superior durability performance compared to conventional thermal heads. That is, compared to printing using the conventional thermal head, in which printing defects occurred after 30 million characters, in printing using the thermal head of this embodiment, no printing defects occurred after printing 30 million characters. There wasn't.

Example 2: A heat generating/resistance layer having the same thickness was deposited in the same manner as in Example 1 except that the source gas was C2H8 and the discharge power was 1.5 W/crn'.

Next, when a thermal head was manufactured in the same manner as in Example 1 and an electrical pulse signal was input, the heating resistive element was not destroyed even when the electrical pulse signal input reached 1XloIO times. Further, no change in resistance value was observed.

Next, in the same manner as in Example 1, printing was performed on thermal recording paper, further printing was performed as a thermal transfer type, and further printing was performed on type paper, and as in Example 1, sufficient durability was obtained. It was confirmed that

Example 3: A glaze layer was provided on a support made of an alumina ceramic plate as a base, and a heat generating resistor layer was formed on the surface of the base. The deposition of the zero heat generating resistor layer was shown in FIG. The process was carried out by sputtering using a device manufactured by the company. 99.9% purity for sputtering target
The above graphite was used, and H2 was used as the raw material gas.

The conditions during the deposition were as shown in Table 1. Incidentally, during the deposition, the opening degree of the valve was continuously changed to change the flow rate of H2 gas to form a heat generating resistor layer having the thickness shown in Table 1.

Using the resistive layer thus formed, a thermal head was produced in the same manner as in Example 1-, and an electrical pulse signal was input to the heat generating resistor element of the thermal head in the same manner as in Example 1 to print. As a result, it was confirmed that the durability was excellent as in Example 1.

[Effects of the Invention] According to the present invention as described above, thermal responsiveness, thermal conductivity, A thermal recording head with extremely good heat resistance and/or durability is provided.

Further, the heating resistance layer of the present invention is easy to form. In particular, the present invention provides a thermal recording head having an excellent heat generating resistance layer with good wear resistance and/or a low coefficient of friction.

Furthermore, according to the present invention, the content of hydrogen atoms in the heat generating resistive layer is distributed non-uniformly in the film thickness direction, which improves various properties such as heat storage, heat dissipation, and adhesion between the substrate and the resistive layer. characteristics can be easily realized.

[Brief explanation of drawings]

FIG. 1 is a partial plan view of the thermal recording head of the present invention;
The figure is a sectional view taken along line II-II. 3 to 8 are graphs showing the distribution of hydrogen atom content in the heating resistance layer. 9 and 10 are partial cross-sectional views of the thermal recording head of the present invention. FIG. 11 shows 1. used for manufacturing the thermal recording head of the present invention. FIG. 2: Substrate 4: Heat generating resistive layer 6.7: Electrode 1101: Deposition chamber 1137: Substrate Agent Patent attorney Seki Yamashita Child 1 Figure 2 Figure 7 Figure 1 O Figure 3 Figure 4 Figure D Figure 6 Figure OC Figure 7 Figure 8 OC

Claims (3)

[Claims] (1) In a thermal recording head in which at least one set of a heating resistance layer and at least one pair of electrodes electrically connected to the heating resistance layer is formed on a substrate, the heating resistance layer has carbon atoms as a matrix. 1. A thermal recording head comprising an amorphous material containing hydrogen atoms, the heating resistor layer having hydrogen atoms distributed non-uniformly in the film thickness direction. (2) Hydrogen atom content in the heating resistance layer is 0.00
The thermal recording head of claim 1, wherein the thermal recording head has a content of 0.01 to 30 atom %. (3) The thermal recording head according to claim 1, wherein the substrate has a surface layer made of an amorphous material containing carbon atoms as a matrix on the side on which the heating resistance layer is formed.