JPH1199681A - Thermal head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce corrosion and wear of a protective film and prevent the protective film from cracking and peeling by providing a protective film containing carbon and nitrogen, and further hydrogen as main components on a heating resistor. SOLUTION: The thermal head 66 is comprised of a grazed layer 82, a heating resistor 84, electrodes 86 and a protective film on a substrate 80. The protective film is composed of a lower layer protective film 88 whose main components are a ceramic and a carbon-nitrogen (C-N) protective film 90 as an upper layer protective film. The C-N protective film 90 is formed of carbon and nitrogen as main components, and the state of existence and composition ratio of carbon atoms and nitrogen atoms in the C-N protective film 90 are not specified. However, by containing nitrogen atoms in the C-N protective film 80 so that they may form a triple bond with carbon atoms and C≡N may be formed, high hardness can be achieved and the durability of the thermal head 66 can be increased. The C-N protective film 90 may contain also hydrogen. In such case, stress in the film can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to various printers,
It belongs to the technical field of a thermal head for performing thermal recording used as a recording means in a plotter, a facsimile, a recorder, and the like.

[0002]

2. Description of the Related Art Thermal recording using a thermal material formed by forming a thermal recording layer using a film or the like as a support is used for recording an ultrasonic diagnostic image. In addition, thermal recording has advantages such as no need for wet development processing and easy handling, and in recent years, in recent years, not only small-sized image recording such as ultrasonic diagnosis but also CT diagnosis and MRI diagnosis have been performed. For applications requiring large and high-quality images, such as X-ray diagnosis and the like, the use for image recording for medical diagnosis is also being studied.

As is well known, in thermal recording, a glaze in which a heating element having a heating element and electrodes is arranged in one direction (main scanning direction) for recording an image by heating a thermosensitive recording layer of a thermosensitive material. While the glaze is slightly pressed against the heat-sensitive material (heat-sensitive recording layer) using the formed thermal head, while moving both relatively in the sub-scanning direction orthogonal to the main scanning direction, image data supply such as MRI is performed. In accordance with the image data of the recorded image supplied from the source, energy is applied to the heating element of each pixel of the glaze to generate heat, thereby heating the heat-sensitive recording layer of the heat-sensitive material to perform image recording.

In the glaze of this thermal head, a protective film is formed on the surface of the glaze of the thermal head in order to protect the heating element for heating the heat-sensitive material or the electrodes. Therefore,
It is this protective film that comes into contact with the thermosensitive material during thermal recording, and the heating element heats the thermosensitive material through the protective film,
Thus, thermal recording is performed. The material of the protective film is usually made of a ceramic having wear resistance, but the surface of the protective film slides on the heat-sensitive material in a heated state during the heat-sensitive recording. And deteriorate.

[0005] If the wear progresses, density unevenness occurs in the thermal image or the strength of the protective film cannot be maintained, so that the function of protecting the heating element and the like is impaired.
Image recording cannot be performed (head shortage). In particular, in applications where high-quality and high-quality multi-gradation images are required, such as in the medical applications described above, a high-rigidity support such as a polyester film is used in order to achieve high quality and high image quality. Using a heat-sensitive film that uses the body,
The recording temperature (applied energy) and the pressing force of the thermal head on the heat-sensitive material are set to be higher. for that reason,
Compared to normal thermal recording, the force and heat applied to the protective film of the thermal head are greater, and wear and corrosion (wear due to corrosion) are more likely to progress.

[0006]

As a method for preventing the abrasion of the protective film of the thermal head and improving the durability, many techniques for improving the performance of the protective film have been studied. As a protective film having excellent wear resistance and corrosion resistance, a protective film containing carbon as a main component (hereinafter referred to as a carbon protective film) is known.

For example, JP-B-61-53955 and JP-B-4-62866 (divisional applications of the aforementioned application) disclose a carbon protective film having a Vickers hardness of 4500 kg / mm ² or more as a protective film for a thermal head. By disposing a thermal head, a thermal head that realizes excellent responsiveness by sufficiently thinning a protective film together with excellent wear resistance, and a method of manufacturing the same are disclosed. Such a carbon protective film has characteristics very similar to diamond,
It is very hard and chemically stable. Therefore, it exhibits excellent characteristics in terms of abrasion resistance and corrosion resistance against sliding contact with a heat-sensitive material. However, while the carbon protective film has excellent wear resistance, it is brittle because of its hardness, that is, its toughness is low, and cracking and peeling occur relatively easily due to heat shock or thermal stress caused by heating of the heating element. There is a problem that it is.

To solve such a problem, Japanese Patent Application Laid-Open No.
No. 2628 has a two-layer structure of a lower silicon-based compound layer and an upper layer of a diamond-like carbon layer, thereby greatly reducing wear and breakage of the protective film due to heat shock or the like. A thermal head capable of performing high-quality recording for a long time is disclosed. In the same publication, the adhesion of the silicon-based compound layer to the diamond-like carbon layer is improved by subjecting the surface of the silicon-based compound layer to a surface treatment in a reducing atmosphere by plasma CVD or the like. However, the adhesion between the diamond-like carbon layer and the silicon-based compound layer is still insufficient, and stress due to the difference in the coefficient of thermal expansion of each of these layers, and the difference between the thermal material and the thermal head (glaze) during recording. Cracking and peeling also occur due to mechanical impact or the like caused by the foreign matter mixed therein.

On the other hand, Japanese Patent Publication No. Hei 6-23433 discloses that
C-F bond of fluorine and nitrogen or fluorine, nitrogen and hydrogen,
A thermal head has been disclosed in which a coating mainly containing carbon having a C—N bond is formed as a protective film to thereby improve the adhesion and heat resistance of the protective film. However, since this protective film contains fluorine, it has a problem that its wear resistance is poor. In addition, since this thermal head does not have a lower protective film and forms these protective films, the film stress balance cannot be obtained,
There is also a problem that the protective film is easily peeled. If the protective film is cracked or peeled in this way, wear, corrosion, and even wear due to corrosion will progress from this point, and the durability of the thermal head will be reduced. You can't get it.

An object of the present invention is to solve the above-mentioned problems of the prior art, and a thermal head having a protective film containing carbon as one of the main components, in which the protective film is extremely resistant to corrosion and wear. Prevents the protective film from cracking or peeling even with heat and mechanical shock, has sufficient durability, and can perform high-quality thermal recording stably for a long period of time. An object of the present invention is to provide a thermal head.

[0011]

According to the present invention, there is provided a thermal head having a heating resistor on a substrate, wherein the heating resistor comprises carbon and nitrogen as main components on the heating resistor. Or a thermal head having a protective film containing hydrogen.

Here, it is preferable that at least one lower protective film mainly composed of ceramics is provided between the heating resistor and the protective film.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a thermal head according to the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.

FIG. 1 is a schematic diagram showing an example of a thermal recording apparatus using a thermal head according to the present invention. A thermosensitive recording apparatus (hereinafter, referred to as a recording apparatus) 10 shown in FIG. 1 performs thermosensitive recording on a thermosensitive material (hereinafter, referred to as a thermosensitive material A) which is a cut sheet of a predetermined size such as a B4 size. A loading unit 14 in which a magazine 24 containing the thermal material A is loaded, a feeding and transporting unit 16, a recording unit 20 for performing thermal recording on the thermal material A by a thermal head 66,
And a discharge unit 22.

In such a recording apparatus 10, one heat-sensitive material A is pulled out of the magazine 24, the heat-sensitive material A is transported to the recording section 20, and the thermal head 66 is pressed against the heat-sensitive material A while the glaze is extended. The heat-sensitive material A is transported in the sub-scanning direction orthogonal to the existing direction, that is, the main scanning direction (perpendicular to the paper surface in FIGS. 1 and 2), and each heating element generates heat in accordance with a recorded image (image data). ,
Thermal recording is performed on the thermal material A.

The heat-sensitive material A is obtained by forming a heat-sensitive recording layer on one surface of a support such as a transparent resin film such as a polyethylene terephthalate (PET) film or paper. Such a heat-sensitive material A is formed into a laminate (bundle) of a predetermined unit of 100 sheets or the like and packaged in a bag, a band, or the like. Are stored in the magazine 24 of the recording apparatus 10, and are taken out one by one from the magazine 24 and provided for thermal recording.

The magazine 24 is a housing having a lid 26 that can be opened and closed. The magazine 24 stores the heat-sensitive material A and is loaded into the loading section 14 of the recording apparatus 10. The loading unit 14 includes the recording device 10
Insertion hole 30 formed in housing 28 of
And guide rolls 34, 34, and a stop member 36. The magazine 24 is inserted into the insertion port 30 with the lid 26 side first.
Then, while being guided by the guide plate 32 and the guide roll 34 and being pushed to a position where it comes into contact with the stop member 36, the recording device 10 is loaded into a predetermined position of the recording device 10. The loading section 14 is provided with an opening / closing mechanism (not shown) for opening and closing the lid 26 of the magazine.

The supply / transportation means 16 takes out one heat-sensitive material A from the magazine 24 loaded in the loading section 14 and transports it to the recording section 20, and uses a suction cup 40 which adsorbs the heat-sensitive material A by suction. Single wafer mechanism, conveyance means 4
2, a transport guide 44, and a pair of regulating rollers 52 located at the exit of the transport guide 44. The conveying means 42 includes a conveying roller 46 and a pulley 4 coaxial with the conveying roller 46.
7a, a pulley 47b and a tension pulley 47c connected to a rotary drive source, an endless belt 48 stretched over the three pulleys, and a nip roller 50 forming a roller pair with the transport roller 46. 40
The leading end of the heat-sensitive material A sheet-fed by the conveying roller 46
And the nip roller 50 to transport the heat-sensitive material A.

When a recording start instruction is issued in the recording device 10, the lid 26 is opened by the opening / closing mechanism,
The sheet-feeding mechanism using the suction cup 40 takes out one heat-sensitive material A from the magazine 24 and transports the front end of the heat-sensitive material A to the conveying means 42.
(A roller pair composed of the transport roller 46 and the nip roller 50). When the heat-sensitive material A is nipped by the conveyance roller 46 and the nip roller 50, the suction by the suction cup 40 is released, and the supplied heat-sensitive material A is guided by the conveyance guide 44 to the regulating roller pair 52 by the conveyance means 42. Conveyed. When the heat-sensitive material A to be used for recording is completely discharged from the magazine 24, the lid 26 is closed by the opening / closing means.

The distance from the conveying means 42 to the regulating roller pair 52 by the conveying guide 44 is set slightly shorter than the length of the heat-sensitive material A in the conveying direction. The leading end of the heat-sensitive material A reaches the regulating roller pair 52 by carrying by the carrying means 42,
The regulating roller pair 52 is initially stopped, and the leading end of the heat-sensitive material A is temporarily stopped and positioned here. When the tip of the heat-sensitive material A reaches the regulating roller pair 52, the temperature of the thermal head 66 (glaze) is confirmed. If the temperature of the thermal head 66 is a predetermined temperature, the regulating roller pair 5
2, the transfer of the heat-sensitive material A is started.
It is transported to the recording unit 20.

The recording section 20 includes a thermal head 66, a platen roller 60, a cleaning roller pair 56, and a guide 5.
8, a heat sink 67 for cooling the thermal head 66,
It has a cooling fan 76 and a guide 62. The thermal head 66 performs thermal recording at a recording (pixel) density of about 300 dpi, for example, capable of recording an image up to a maximum of B4 size. Except for having a characteristic of the protective film, thermal recording on the thermal material A is performed. Heating element is one direction (main scanning direction)
Has a known configuration in which glazes are arranged. A heat sink 67 for cooling is fixed to the thermal head 66. The thermal head 66 is supported by a support member 68 that is rotatable up and down around a fulcrum 68a. This thermal head 66
Will be described later in detail. The width (main scanning direction), resolution (recording density), recording gradation and the like of the thermal head 66 of the present invention are not particularly limited, but the width is 5 cm to 5 cm.
Preferably, the recording density is 50 cm, the resolution is 6 dot / mm (about 150 dpi) or more, and the recording gradation is 256 or more.

The platen roller 60 rotates in the direction of the arrow in the figure at a predetermined image recording speed while holding the heat-sensitive material A at a predetermined position, and rotates in the sub-scanning direction (the direction of the arrow x in FIG. 2) orthogonal to the main scanning direction. ) To transport the heat-sensitive material A. The cleaning roller pair 56 is a roller pair comprising an adhesive rubber roller (upper side in the figure) which is an elastic body and a normal roller. The adhesive rubber roller removes dust and the like adhered to the heat-sensitive recording layer of the heat-sensitive material A, It prevents dust from adhering to the glaze and adversely affecting image recording.

In the illustrated recording apparatus 10, before the heat-sensitive material A is conveyed, the support member 68 rotates upward,
This is a standby position immediately before the glaze of the thermal head 66 comes into contact with the platen roller 60. When the conveyance by the above-described regulating roller pair 52 is started, the heat-sensitive material A
Next, it is nipped by the cleaning roller pair 56,
It is transported while being guided by the guide 58. When the leading end of the heat-sensitive material A is conveyed to the recording start position (the position corresponding to the glaze), the support member 68 rotates downward, and the heat-sensitive material A is sandwiched between the glaze and the platen roller 60,
The glaze is pressed against the recording layer, and the heat-sensitive material A
While being held at a predetermined position by the platen roller 60, the sheet is conveyed in the sub-scanning direction by the platen roller 60 and the like.
With this conveyance, each of the glaze heating elements is heated according to the recorded image, so that thermal recording is performed on the thermal material A.

The heat-sensitive material A on which the heat-sensitive recording has been completed is conveyed to the platen roller 60 and the conveying roller pair 63 while being guided by the guide 62, and is discharged to the tray 72 of the discharge section 22. The tray 72 protrudes outside the recording apparatus 10 through a discharge port 74 formed in the housing 28, and the heat-sensitive material A on which an image is recorded is discharged to the outside through the discharge port 74 and is taken out.

FIG. 2 is a schematic cross-sectional view of the glaze (heating element) of the thermal head 66. In the illustrated example, the glaze is on the substrate 80 (the thermal head 66 in the illustrated example).
Is pressed by the heat-sensitive material A from above, so that it is formed on the lower side in FIG. 2), a heat generation (resistance) body 84 formed thereon, and a heat generation (resistance) body 84 formed thereon It has an electrode 86 to be formed, and a protective film for protecting the heating element 84 and further the electrode 86 and the like formed thereon. In the illustrated example, the protective film has a two-layer configuration, and includes a lower protective film 88 mainly composed of ceramic and formed to cover the heating element 84 and the electrode 86;
A protective film composed of a protective film mainly composed of carbon and nitrogen, that is, a carbon-nitrogen protective film (hereinafter, referred to as a CN protective film) 90 formed as an upper protective film on the lower protective film 88. .

The thermal head 66 of the present invention can have basically the same configuration as a known thermal head except for this protective film. Therefore, there is no particular limitation on the other layer configuration and the material of each layer, and various known materials can be used. Specifically, the substrate 80 is made of an electrically insulating material such as heat-resistant glass, ceramics such as alumina, silica, and magnesia, and the glaze layer 82 is made of a heat-resistant glass or a heat-resistant resin such as a polyimide resin. As the electrode 86, various kinds of conductive materials such as aluminum, gold, silver, and copper can be used as the heating resistor such as nichrome (Ni-Cr), tantalum, and tantalum nitride. The glaze (heating element) includes vacuum evaporation and CVD (Chemical Vapo).
r Deposition), a thin film type heating element formed by using a so-called thin film forming technique such as sputtering and a photo-etching method, and a thick film formed by using a so-called thick film forming technique by printing and firing such as screen printing and baking. Although a type heating element is known, the thermal head 66 used in the present invention may be formed by any method.

As described above, the thermal head 6 shown in FIG.
6 has a two-layered protective film of a CN protective film 90 and a lower protective film 88. By having such a lower protective film 88, more favorable results can be obtained in terms of wear resistance, corrosion resistance, corrosion wear resistance, etc., and higher durability,
A long-life thermal head can be realized. The lower protective film 88 formed on the thermal head 66 of the present invention is not particularly limited as long as it is mainly composed of ceramics, which is a material having heat resistance, corrosion resistance and abrasion resistance that can be a protective film of the thermal head. Instead, various ceramic materials can be used.

Specifically, silicon nitride (Si ₃ N ₄ ), silicon carbide
(SiC), tantalum oxide (Ta ₂ O ₅ ), aluminum oxide (Al ₂
O ₃ ), sialon (SiAlON), ration (LaSiON), silicon oxide (SiO ₂ ), aluminum nitride (AlN), boron nitride (BN),
Selenium oxide (SeO), titanium nitride (TiN), titanium carbide (Ti
C), titanium carbonitride (TiCN), chromium nitride (CrN), and mixtures thereof. Among them, silicon nitride, silicon carbide, sialon, and the like are preferably used in terms of ease of film formation, manufacturing adequacy such as manufacturing cost, and a balance between mechanical abrasion and chemical abrasion. Further, the lower protective film may contain a small amount of an additive such as a semi-metal or metal described later for adjusting the physical properties. There is no particular limitation on the method of forming the lower protective film 88, and the lower protective film 88 is formed by a known method of forming a ceramic film (layer) using the above-described thick film forming technology, thin film forming technology, or the like.

The thickness of the lower protective film 88 is not particularly limited, but is preferably about 0.2 μm to 20 μm, more preferably about 2 μm to 15 μm. By setting the thickness of the lower protective film 88 within the above range, a favorable result can be obtained in that a balance between abrasion resistance and thermal conductivity (that is, recording sensitivity) can be appropriately obtained. Further, the lower protective film 88 may have a multilayer structure. When the lower protective film 88 has a multi-layer structure, the lower protective film 88 may have a multi-layer structure using different materials, or may have a multi-layer structure having different layers of the same material with different densities or both. It may be something.

Here, as described above, a protective film containing carbon as a main component, for example, a DLC protective film (= Diamond Like Carbon protective film) is formed on the lower protective film 88 to form two layers. With the structure, the excellent wear resistance and corrosion resistance of the DLC protective film can be obtained, and the above-mentioned heat shock, thermal stress, cracking and peeling of the CN protective film 90 can be suppressed to some extent. . However, if a protective film containing only carbon as a main component is provided as the upper protective film, the protective film may be cracked or peeled off due to stress due to a difference in thermal expansion coefficient from the lower protective film 88.

In order to solve such a problem, the thermal head 66 of the present invention provides a C-N protection film 9 containing carbon and nitrogen as main components or further containing hydrogen on a heating resistor.
By forming 0, it is possible to effectively prevent cracking, peeling, and the like of the protective film with a protective film having a moderately high hardness. Moreover, in the illustrated example, by forming a CN protective film 90 as an upper protective film on the lower protective film 88 mainly composed of ceramic, the adhesion of the upper protective film to the lower protective film 88 and The present invention achieves moderately high hardness while improving the stress balance, and more suitably prevents cracking, peeling, and the like of the protective film.

Further, as described above, the CN protective film 90
Is very chemically stable, so that chemical corrosion of the lower protective film 88, which is a ceramic film, can be effectively prevented, and the life of the thermal head can be extended. Therefore, the thermal head 66 of the present invention has sufficient durability and exhibits high reliability over a long period of time, so that high-quality thermal recording can be stably performed over a long period of time. In particular, it has sufficient durability even in applications where recording under high energy and high pressure is performed on heat-sensitive materials that use highly rigid supports such as polyester films, as in the medical applications described above. High reliability can be demonstrated across the board.

The CN protective film 90 is basically formed mainly of carbon and nitrogen. The existence state and composition ratio of carbon atoms and nitrogen atoms in the C—N protective film 90 are not particularly limited, but the nitrogen atoms are formed by C—N so as to form a C—N triple bond with the carbon atoms. It is preferable to be contained in the protective film 90 because higher hardness can be exhibited and durability of the thermal head is improved. The composition ratio of carbon and nitrogen is preferably such that C: N (atomic ratio) is 3: 1 to 3: 4. More preferably, from 2: 1 to 3: 4,
Most preferably, it is 3: 4. With such a composition range, a favorable effect is obtained in terms of abrasion resistance.

The CN protective film 90 may contain hydrogen. In this case, the effect of relaxing the stress inside the film can be obtained. The hydrogen content in this case is 30
It is preferable that the content be atm% or less. If the content is more than 30 atm%, the hardness of the C—N protective film 90 becomes low, and it is easy to wear, which is not preferable. Note that the CN protective film 90
Need not contain hydrogen. Further, the CN protective film 90 may be formed so that the composition ratio of carbon, nitrogen and hydrogen is changed in the thickness direction.

In the present invention, a protective film containing carbon and nitrogen as main components or a protective film containing carbon and nitrogen as main components and further containing hydrogen means the total of the contents of carbon and nitrogen, respectively. Alternatively, a C—N (or C—N—H, but here represented by a C—N protection film) protective film having a total content of carbon, nitrogen and hydrogen of more than 50 atm% refers to such a protective film. CN
As the protective film, a C-N protective film comprising unavoidable impurities other than carbon and nitrogen, or carbon, nitrogen and hydrogen is preferable, and more preferably a high-purity high-purity film having very little or no unavoidable impurity content. A C-N protective film is good. Here, examples of the inevitable impurities include a gas used in the process such as argon (Ar) and a residual gas in a vacuum chamber such as oxygen.
It is preferable that the mixing of these gas components is as small as possible, preferably 2 atm% or less, and more preferably 0.5 atm% or less.

In the present invention, as an additional component other than carbon and nitrogen which forms a protective film containing carbon and nitrogen as main components or further containing hydrogen, and further, other than hydrogen, substances such as fluorine, Si, Ti, Zr, H
Preferable examples include semimetals and metals such as f, V, Nb, Ta, Cr, Mo, and W. When the additive component is a substance such as fluorine, the content thereof in the protective film containing carbon and nitrogen as main components or further containing hydrogen is 50%.
When the additive component is a semimetal or metal such as Si and Ti described above, the content thereof is contained in a protective film containing carbon and nitrogen as main components or further containing hydrogen. The amount is preferably at most 20 atm%. In the following description, as a protective film containing carbon and nitrogen as main components or further containing hydrogen,
The CN protective film 90 will be described as a representative example, but it goes without saying that the description is also applicable to other protective films containing carbon and nitrogen as main components or further containing hydrogen. .

The method of forming the CN protective film 90 is not particularly limited, and may be formed by a known thick film forming technique or thin film forming technique. For example, a solid containing carbon as a main component, such as a sintered carbon material or a glassy carbon material, is used as a target material. The solid material is made to fly to a substrate by plasma, and nitrogen gas or an alkylamine-based gas is ionized by this plasma to convert nitrogen Together with a sputtering method for forming a film on a thermal head, or a plasma CV for forming a film on a thermal head by decomposing a mixed gas of a hydrocarbon gas and an alkylamine-based gas by microwave ECR plasma.
The D method and the like are preferably exemplified. Whichever method is adopted, sufficient durability as a thermal head can be obtained.

The hardness of the CN protective film 90 is not particularly limited, as long as it has a sufficient hardness as a protective film of the thermal head. For example, 3000 in Vickers hardness
kg / mm ² or more is preferably exemplified. Within such a range, the abrasion resistance will be good. This hardness is C-
The hardness may be constant or changed with respect to the thickness direction of the N protective film 90. When the hardness is changed in the thickness direction of the CN protective film 90, the change in the hardness is continuous. Or stepwise.

FIG. 3 shows a conceptual diagram of a sputtering apparatus for forming the CN protective film 90. Sputtering equipment 1
Basically, reference numeral 00 denotes a vacuum chamber 102, a gas introduction unit 104, a sputtering unit 106, and a substrate holder 1.
08.

The vacuum chamber 102 is preferably formed of a non-magnetic material such as SUS 304 so that a magnetic field of a cathode 112 described later is not affected. In addition, the vacuum chamber 10 used for forming the CN protective film 90 of the present invention.
2 is the ultimate pressure of the initial exhaust, 2 × 10 ⁻⁵ Torr or less, preferably 5 × 10 ⁻⁶ Torr or less, and 1 × 10 ⁻⁴ Torr or less during film formation.
It is preferable to have a vacuum sealing property to achieve 1 × 10 ⁻² Torr. As the evacuation unit 110 attached to the vacuum chamber 102, an evacuation unit combining a rotary pump, a mechanical booster pump, and a turbo pump is preferably exemplified, and an evacuation unit using a diffusion pump or a cryopump instead of the turbo pump. Are also preferably exemplified. The evacuation capacity and number of the evacuation means 110 may be appropriately selected according to the volume of the vacuum chamber 102, the gas flow rate during film formation, and the like. In addition, in order to increase the exhaust speed, adjustment of exhaust resistance of piping using bypass piping,
By providing an orifice valve and adjusting its opening degree, etc.
The pumping speed may be adjustable.

The gas introducing section 104 is a section for introducing a gas for generating plasma. The introducing section introduces the gas into the vacuum chamber 102 using a stainless steel pipe or the like which is vacuum-sealed with an O-ring or the like. I do. Further, the amount of gas introduced is controlled by a known method such as a mass flow controller. The gas introduction unit 104 is configured to basically blow out a gas to the vicinity of the plasma generation region in the vacuum chamber 102. Further, it is preferable to optimize the blowing position so as not to affect the distribution of the generated plasma. As a gas for plasma generation for forming the C—N protective film 90, for example, an inert gas such as helium, neon, argon, krypton, or xenon is used. In this respect, argon gas is preferably used. On the other hand, the CN protective film 90
Suitable examples of the raw material gas for producing the gas include a nitrogen-containing gas and an alkylamine-based gas.

In the sputtering, a target material 114 to be sputtered is arranged on the cathode 112, the cathode 112 is set to a negative potential, and plasma is generated on the surface of the target material 114, thereby ejecting the target material 114 (atoms thereof). Is deposited on the surface of a substrate (that is, the glaze of the thermal head 66) disposed oppositely, and deposited to form a film. Here, when the nitrogen gas is ionized by the plasma, the nitrogen gas can be simultaneously deposited on the substrate together with the carbon atoms flying from the target material 114, and the C-N protective film 90 composed of at least two components is formed. be able to. The sputtering means 106 includes the cathode 11
2. It has an arrangement portion of the target material 114, a shutter 116, a DC power supply 118, and the like.

When generating plasma on the surface of the target material 114, the negative side of the DC power supply 118 is directly connected to the cathode 112, and a DC voltage of 300 V to 1000 V is applied. The output of the DC power supply 118 is 1 kW to
A range of about 10 kW, which is necessary for generating the C—N protective film 90 and has a sufficient output, may be appropriately selected. The shape of the cathode 112 is the same as that of the C—N protection film 90.
May be determined as appropriate according to the shape of the substrate on which is formed. In addition, in terms of arc prevention, etc., 2 kHz to 20 kHz
A DC power supply that has been pulse-modulated can also be suitably used. In addition, a high frequency power supply can be used to generate plasma. When a high-frequency power supply is used, plasma is generated by applying a high-frequency voltage to the cathode 112 via a matching box. At this time, impedance matching is performed by a matching box, and adjustment is performed so that the reflected wave of the high-frequency voltage is 25% or less of the incident wave. 13.56 MH for industrial use as high frequency power supply
z, in the range of about 1 kW to 10 kW, the C-N protection film 9
What has a sufficient output necessary for generating 0 may be appropriately selected.

The target material 114 may be directly fixed to the cathode 112 using In-based solder or mechanical fixing means, but usually, a backing plate 120 made of oxygen-free copper or stainless steel is fixed to the cathode 112. Then, the target material 114 is attached thereon as described above. In addition, the cathode 112 and the backing plate 1
20 is configured to be water-coolable, whereby the target material 114 is also indirectly water-cooled. Note that the CN protective film 90
Preferable examples of the target material 114 used for forming the layer include a sintered carbon material and a glassy carbon material. Further, the shape may be appropriately determined according to the shape of the substrate.

The formation of the C—N protection film 90 is performed by the cathode 11
Magnetron sputtering, in which a magnet 112a such as a permanent magnet or an electromagnet is disposed inside 2, and a magnetic field is formed on the surface of the target material 114 to confine plasma and perform sputtering, can also be suitably used. This magnetron sputtering is preferable in that the film forming speed is high. The shape, position and number of the permanent magnets and electromagnets, the strength of the generated magnetic field, and the like are appropriately determined according to the thickness and thickness distribution of the C-N protective film 90 to be formed, the shape of the target material 114, and the like. Further, it is preferable to use a magnet capable of generating a high magnetic field such as a Sm-Co magnet or a Nd-Fe-B magnet as the permanent magnet since plasma can be sufficiently confined.

The substrate holder 108 holds the thermal head 66
Is fixed, and the glaze serving as a substrate is fixed facing the cathode 112. If necessary, the glaze may be configured to be rotatable or movable with respect to the cathode 112, and may be appropriately selected according to the size of the substrate and the like. The distance between the substrate and the target material 114 is not particularly limited, and a distance at which the film thickness distribution is uniform may be selected and set within a range of about 20 mm to 200 mm.

In manufacturing the thermal head 66 of the present invention, in order to further improve the adhesion between the C—N protection film 90 and the lower protection film 88, a lower layer is formed before the formation of the C—N protection film 90. It is preferable to etch the surface of the protective film 88 with plasma. To this end, in the illustrated sputtering apparatus 100, a bias power supply 122 for applying a high-frequency voltage is connected to the substrate holder 108. The bias power supply 122 applies a high-frequency voltage to the substrate via the matching box, and is used for industrial use.
The frequency may be appropriately selected from those of about 1 kW to 5 kW at 56 MHz. The etching strength may be determined by using a bias voltage applied to the substrate as a guide.
Optimization may be appropriately performed in the range of 0 V to 500 V.

FIG. 4 is a conceptual diagram of another example of a film forming apparatus for forming the CN protective film 90. The illustrated film forming apparatus 130
Is basically a vacuum chamber 132 and a gas introduction unit 13
4, a first sputtering unit 136, a second sputtering unit 138, a plasma generating unit 140, a bias power source 142, and a substrate holder 144. Such a film forming apparatus 130 has two film forming means by sputtering and a film forming means by plasma CVD in a system, that is, in a vacuum chamber 132, and takes out a thermal head 66 as a film forming substrate from the system. Without, by sputtering using different targets or by sputtering and plasma CVD
Thus, films having different compositions can be continuously formed. Therefore, by using the film forming apparatus 130,
It is possible to continuously form a plurality of different layers without releasing the inside of the system to atmospheric pressure or the like, so that an efficient thermal head can be manufactured.

The vacuum chamber 132 is preferably made of a non-magnetic material such as SUS 304 so that a cathode 148 and the like and a magnetic field for generating plasma are not affected. Further, the vacuum chamber 132 used for forming the C—N protective film 90 of the thermal head 66 of the present invention has an initial exhaust pressure of 2 × 10 ⁻⁵ Torr or less, preferably 5 × 1 ⁻⁵ Torr.
0 ^-6 Torr or less, 1 × 10 ^-4 Torr to 1 × 10 ^-2 To during film formation
It preferably has a vacuum sealing property to achieve rr. As the evacuation unit 146 attached to the vacuum chamber 132, the same unit as the evacuation unit 110 of the sputtering apparatus 100 can be used.

A place where an arc is generated by plasma or an electromagnetic wave for plasma generation in the vacuum chamber 132 may be covered with an insulating member, if necessary. As the insulating member, MC nylon, Teflon (PTFE), PPS
(Polyphenylene sulfide), PEN (polyethylene naphthalate), PET (polyethylene terephthalate) and the like can be used. When using PEN, PET, or the like, care must be taken when using such a material because the degree of vacuum may be reduced by degassing from the insulating member.

The gas introduction section 134 has two gas introduction pipes 1.
34a and a gas introduction pipe 134b. The gas introduction pipe 134a is a pipe for introducing a gas for generating plasma, while the gas introduction pipe 134b is a pipe for introducing a reaction gas of plasma CVD, and both of the introduction sections are vacuum-sealed with an O-ring or the like. A gas is introduced into the vacuum chamber 132 using a stainless steel pipe or the like. Further, the amount of gas introduced is controlled by a known method such as a mass flow controller. Both gas introduction pipes 134a and 134b should both be optimized to wipe gas to the extent possible near the plasma generation area within the vacuum chamber 132 and not affect the distribution of generated plasma. preferable. In particular, the position at which the reactant gas is blown out of the gas introduction pipe 134b affects the film thickness distribution, and therefore it is preferable to optimize the position according to the shape of the substrate (glaze of the thermal head 66).

A plasma for forming the CN protective film 90
Examples of gas for generating gas include helium, neon,
Uses inert gas such as argon, krypton, xenon, etc.
Price and availability, among others
In this case, argon gas is preferably used. On the other hand, CN
As a reaction gas for forming the protective film 90, a C—N bond is used.
Mixed gas of a gas having an union and a gas having a CH bond
Using As a gas having a C—N bond, N (C
H_Three)_Three, N (C_TwoH_Five)_Three, HN (C_TwoH_Five)_Two, H
_TwoN (CH_Three), HN (C_TwoH_Five)_Two, H_TwoN (C_TwoH
_Five) And the like.
Gases having a C—H bond include methane and ethanol.
Carbon such as propane, propane, ethylene, acetylene, benzene, etc.
Hydrogen compounds are preferably exemplified. In addition, the C—H connection
Gas with N and N_TwoMixed gas with gas (nitrogen gas)
It is preferably used. The gas introduction pipe 134a and the gas
The gas introduction pipes 134b are both mass
It is necessary to adjust the sensor of the low controller.

The first sputtering means 136 and the second
The sputtering means 138 both form a film on the substrate surface by the above-described sputtering, and the first sputtering means 136 has a cathode 148, an arrangement portion of the target material 150, a shutter 152, a DC power supply 154, and the like. It is composed. In addition, the cathode 148
Inside, a magnet 148a is arranged, and further, a backing plate 162 for fixing the target material 150 is attached. On the other hand, the second sputtering means 138 includes a cathode 156, an arrangement portion of the target material 150, a shutter 158.
And a DC power supply 160 and the like. Similarly, a magnet 156a is arranged in the cathode 156,
Backing plate 16 for fixing target material 150
4 is stuck. Such first sputtering means 1
36 and the second sputtering means 138 are both provided by the sputtering means 10 of the sputtering apparatus 100.
It is the same as 6.

In the film formation by plasma CVD, a DC discharge, a high-frequency discharge, a DC arc discharge, a micro ECR wave discharge, or the like can be used as a plasma generating means.
Among them, the micro ECR wave discharge has a high plasma density,
This is advantageous for high-speed film formation, and is particularly suitable for forming the CN protective film 90 in that, for example, low-temperature film formation can be performed. In the illustrated example, the film forming apparatus 130 includes a CN protective film 9 formed by plasma CVD.
The plasma generating means 140 includes a microwave power supply 166, a magnet 168, a microwave introduction pipe 170, a coaxial converter 172, a dielectric plate 174, and a radial antenna 176. And so on.

The DC discharge generates a plasma by applying a negative DC voltage between the substrate and the electrode. The DC power supply used for the DC discharge is of the order of 1 to 10 kW.
A film having a sufficient output necessary and necessary for forming the N protective film 90 may be appropriately selected. In terms of arc prevention,
A DC power supply pulse-modulated to 2 kHz to 20 kHz can also be suitably used. The high-frequency discharge generates plasma by applying a high-frequency voltage to an electrode via a matching box. At this time, impedance matching is performed by a matching box, and adjustment is performed so that the reflected wave of the high-frequency voltage is 25% or less of the incident wave. As a high-frequency power supply for performing high-frequency discharge, 13.5 for industrial use is used.
At 6 MHz, a film having a necessary and sufficient output for a target film formation in a range of about 1 kW to 10 kW may be appropriately selected. Also, a pulse-modulated high-frequency power supply can be used. DC arc discharge uses a hot cathode to generate a plasma. As the hot cathode, tungsten, lanthanum boride (LaB ₆ ), or the like can be used. DC arc discharge using a hollow cathode can also be used. As a DC power supply used for DC arc discharge, 1 kW to 10 kW
In the range of about kW and about 10 to 150 A, what has necessary and sufficient output for the intended film formation may be appropriately selected.

The microwave ECR discharge is performed by the microwave and E
A plasma is generated by the CR magnetic field,
As described above, the plasma generating means 140 in the illustrated example generates plasma by the microwave discharge. As the microwave power supply 166, 2.45 GHz for industrial use
In the range of about 1 kW to 3 kW, a material having a necessary and sufficient output for forming the CN protective film 90 or the like may be appropriately selected. For generating the ECR magnetic field, a permanent magnet or an electromagnet capable of forming a desired magnetic field may be appropriately used. In the illustrated example, a Sm-Co magnet is used as the magnet 168. For example, when a microwave of 2.45 GHz is used, the ECR magnetic field is 875 G (Gauss), and therefore a magnet having a magnetic field of 500 G to 2000 G in the plasma generation region may be used. The microwave is introduced into the vacuum chamber 132 by the microwave introduction pipe 170 and the coaxial converter 17.
2, using a dielectric plate 174 or the like. Since the state of formation of the magnetic field and the introduction path of the microwave affect the distribution of the film thickness of the C-N protective film 90 and the like, it is preferable to optimize the film thickness to be uniform.

The substrate holder 144 holds the thermal head 66
Is fixed. Here, the film forming apparatus 130
The substrate holder 144 includes film forming means, that is, sputtering means 136 and 138, and plasma generating means 14 for performing plasma CVD.
The substrate holder 144 is held by a rotating substrate 180 which swings so that the glaze serving as a substrate can face the substrate.
What is necessary is just to select suitably according to the size of a board | substrate, etc. Further, a heater may be provided on the upper surface of the substrate holder 144 so that sputtering may be performed while heating. The distance between the substrate and the target material 150 or the radial antenna 176 is not particularly limited.
A distance at which the film thickness distribution becomes uniform may be selected and set within a range of about 0 mm.

Here, even in the case of using the apparatus of the illustrated example,
In order to improve the adhesion between the CN protective film 90 and the lower protective film 88, it is preferable to etch the surface of the lower protective film 88 with plasma before forming the CN protective film 90.
Further, in order to obtain a hard film by plasma CVD, it is necessary to form a film while applying a negative bias voltage to the substrate. For this purpose, the film forming apparatus 130 includes the substrate holder 14
4, a bias power supply 142 for applying a high-frequency voltage.
Is connected. The bias power supply 142 applies a high-frequency voltage to the substrate via the matching box.
13.56 MHz for industrial use may be appropriately selected from those of about 1 kW to 5 kW.

The etching strength may be determined by using a bias voltage applied to the substrate as a guide.
Optimization may be appropriately performed in the range of 500 V. Note that such etching may be performed prior to the formation of the CN protective film 90 on the intermediate layer 89. Plasma C
In the case of VD, it is preferable to use a self-bias voltage of a high frequency voltage. The self-bias voltage is negative 100V ~
500V.

As described above, the thermal head of the present invention has been described in detail. However, the present invention is not limited to the above-described example, and it is needless to say that various improvements and changes may be made.

[0061]

Hereinafter, the present invention will be described in more detail with reference to specific examples of the present invention.

Example 1 A sputtering apparatus 100 shown in FIG. 3 was prepared. Details are as follows.

A. Vacuum chamber 102 SUS3 having, as vacuum evacuation means 110, a rotary pump having a pumping speed of 1500 L (liter) / min, a mechanical booster pump having a pump speed of 12000 L / min, and a turbo pump having a pump speed of 3000 L / sec.
A vacuum chamber 102 having a capacity of 0.5 m ³ made of 04 was used. An orifice valve is arranged in the suction part of the turbo pump so that the opening degree can be adjusted from 10 to 100%.

B. The gas introduction unit 104 was configured using a mass flow controller having a maximum flow rate of 100 to 500 [sccm] and a stainless steel pipe having a diameter of 6 mm. The joint between the stainless steel pipe and the vacuum chamber 102 was vacuum-sealed with an O-ring. In addition, as the gas introduction part 104, two gas introduction pipes 104a and 104b for a plasma generation gas and a source gas are provided.
When the C—N protection film 90 described below is generated, argon gas is used as a plasma generation gas, and the C—N protection film 90 is formed.
Nitrogen gas was used as a raw material gas for producing methane.

C. A Sm-Co magnet was disposed inside as a sputtering means 106 permanent magnet 112a,
A rectangular cathode 112 having a width of 600 mm and a height of 200 mm was used. As the backing plate 120, oxygen-free copper processed into a rectangular shape was used, and the cathode 112 was attached to the cathode 112 using In-based solder. The magnet, the cathode 112 and the back surface of the backing plate 120 were cooled by water-cooling the inside of the cathode 112. Also, the DC power supply 11
As 8, a DC power supply having a maximum potential of 8 kW and a negative potential was used. The DC power supply 118 has a frequency of 2 kHz to 10 kHz.
It is configured so that it can be modulated in a pulse shape in the range of z.

D. Substrate holder 108 Substrate (that is, glaze 82 of thermal head 66)
The distance between the target material 114 and the target material 114 is adjustable between 50 mm and 150 mm. When the C—N protective film 90 described below was generated, the distance between the substrate and the target material 114 was 100 mm. Further, the holding portion of the thermal head by the substrate was set to a floating potential so that a high frequency voltage for etching could be applied. Further, the substrate holder 108
A heater was provided on the surface to form a film while heating.

E. Bias power supply 122 A high-frequency power supply was connected to the substrate holder 108 via a matching box. The high frequency power supply has a frequency of 13.56M
At Hz, the maximum power is 3 kW. The high-frequency power supply is configured to be capable of adjusting a high-frequency output in a negative range of 100 V to 500 V by monitoring a self-bias voltage.

<Preparation of Thermal Head> Using such a sputtering apparatus 100, the surface of the glaze (the surface of the silicon nitride film) of the thermal head (KGT-260-12MPH8 manufactured by Kyocera Corporation) was The -N protective film 90 was formed, and the thermal head of the present invention was manufactured. In addition, the thermal head which is the basis of this has a silicon nitride film (Si ₃ N ₄ ) having a thickness of 11 μm as a protective film on the glaze surface. Therefore, in this embodiment, this silicon nitride film is the lower protective film 88, and the CN protective film 90 serving as the upper protective film is formed on the lower protective film 88.

In the above sputtering apparatus 100,
As the glaze 82 faces the target material 114,
The thermal head 66 was fixed to the substrate holder 108 in the vacuum chamber 102. Note that masking was performed in advance on portions other than the portion where the upper protective film for the thermal head was formed (that is, other than glaze). After fixing the thermal head, the pressure in the vacuum chamber 102 is 5 × 10 ⁻⁶ Torr.
The chamber was evacuated until. While continuing the vacuum evacuation, an argon gas and a nitrogen gas are introduced by the gas introduction unit 104, and the pressure in the vacuum chamber 102 is increased to 5.0 × 10 ⁻³ To by an orifice valve installed in the turbo pump.
Adjusted to be rr. Next, a high-frequency voltage was applied to the substrate, and the lower protective film (silicon nitride film) was etched at a self-bias voltage of −300 V for 10 minutes.

After completion of the etching, a sintered graphite material as a target material 114 is fixed to the backing plate 120 (attached with an In-based solder), and
The gas flow rate and the orifice valve are adjusted so that the pressure in the gas supply 02 becomes 5 × 10 ⁻³ Torr, and a DC power of 0.5 kW is applied to the target material 114 with the shutter 116 closed.
Min. Then, while maintaining the pressure in the vacuum chamber 102, the DC power is set to 5 kW, the shutter 116 is opened, and sputtering is performed until the formed C—N protective film 90 becomes 1 μm, and a 1 μm thick C-N protective film is formed as an upper protective film. A thermal head on which the -N protective film 90 was formed was manufactured. Further, in exactly the same manner, a thermal head having a 2 μm and 3 μm-thick CN protective film 90 formed thereon as an upper protective film was also manufactured. The film thickness of the C—N protective film 90 was controlled in advance by calculating the film forming speed in advance, calculating the film forming time to achieve a predetermined film thickness, and controlling the film forming time.

<Evaluation of Performance> Using the three types of thermal heads of the present invention and a heat-sensitive material (film CR-AT for dry image recording manufactured by Fuji Photo Film Co., Ltd.), the heat-sensitive recording apparatus shown in FIG. A thermal recording test was performed on 5000 sheets in size. As a result, in any of the thermal heads in which the thickness of the CN protective film 90 is 1 μm, 2 μm, and 3 μm, the CN protective film 90 does not crack or peel off, and hardly any wear is recognized. High durability and good image quality without density unevenness were recorded stably. Further, the composition of the obtained C—N protective film 90 was changed to HFS (Hydrogen Forwardscattering Spectrometr).
As a result of analysis by y), the composition was N / C = 0.7.

Comparative Example 1 A thermal head was manufactured in the same manner as in Example 1 except that a carbon protective film containing no nitrogen was formed instead of the CN protective film 90. Specifically, a carbon protective film was produced basically in the same manner as in Example 1 except that the source gas (nitrogen gas) was not introduced. For this thermal head, the same performance evaluation as in Example 1 was performed. As a result, 500
Before the end of recording of zero sheets, the CN protective film 90 was cracked or peeled off.

Comparative Example 2 A thermal head was manufactured in the same manner as in Example 1 except that a protective film containing fluorine in addition to nitrogen and hydrogen was formed instead of the CN protective film 90. . Specifically, except for introducing a mixed gas of a gas containing nitrogen gas and fluorine as a source gas,
A protective film was produced basically in the same manner as in Example 1. For this thermal head, the same performance evaluation as in Example 1 was performed. As a result, the amount of wear was about five times that of Example 1. In addition, the obtained CN protective film 9
As a result of analyzing the composition of No. 0 by HFS, N / C = 0.2
The composition was as follows.

[Embodiment 2] The film forming apparatus 13 shown in FIG.
0 was prepared. Details are as follows.

A. Vacuum chamber 132 The same one as the vacuum chamber 102 of the sputtering apparatus 100 was used.

B. Gas introduction unit 134 The same configuration as the gas introduction unit 104 of the sputtering apparatus 100 was used. In forming the C—N protective film 90 described later, argon gas was used as a gas for plasma generation, and a mixed gas of methane and trimethylamine was used as a reaction gas.

C. First sputtering means 136 and second sputtering means 138 Sputtering means 106 of sputtering apparatus 100
The same configuration was used.

D. Plasma generating means 140 A microwave power supply 166 having an oscillation frequency of 2.45 GHz and a maximum output of 1.5 kW was used. The microwave was guided to the vicinity of the vacuum chamber 132 by the microwave introduction pipe 170, converted by the coaxial converter 172, and then introduced into the radial antenna 176 in the vacuum chamber 132. The plasma generator has a width of 60
A rectangular shape of 0 mm × 200 mm in height was used. Furthermore, E
For the CR magnetic field, a plurality of Sm-Co magnets were used as the magnets 168,
It was formed by arranging it according to the shape of the dielectric plate 174.

E. The substrate holder 144 used was the same as in the first embodiment. The substrate holder 144 is held on the rotating substrate 180. Also, C-N
When the protective film 90 is formed, the substrate and the radial antenna 176 are formed.
Was set to 150 mm.

F. Bias power supply 142 A high frequency power supply was connected to the substrate holder 144 via a matching box. The high frequency power supply has a frequency of 13.56M
At Hz, the maximum power is 3 kW. The high-frequency power supply is configured to be capable of adjusting a high-frequency output in a negative range of 100 V to 500 V by monitoring a self-bias voltage. In the film forming apparatus 130, the bias power source 142 also serves as a substrate etching unit.

<Preparation of Thermal Head> Using such a film forming apparatus 130, as shown below, a C-N as an upper protective film was formed on the glaze surface of a thermal head (the same as in the first embodiment). A protective film 90 was formed, and a thermal head was manufactured. Therefore, as in the first embodiment, the silicon nitride film is a lower protective film, and the C-layer on which the upper protective film is to be formed.
An N protective film 90 is formed.

The thermal head was fixed to the substrate holder 144 in the vacuum chamber 132 so that the glaze faced the radial antenna 176. Note that masking was performed in advance on portions other than the portion where the upper protective film for the thermal head was formed (that is, other than glaze). After fixing the thermal head, the pressure in the vacuum chamber 132 becomes 5 × 10
Evacuated to ^-6 Torr. While continuing the vacuum evacuation, an argon gas and a mixed gas of methane and trimethylamine (N (CH ₃ ) ₃ ) are introduced by the gas introduction unit 134, and the pressure in the vacuum chamber 132 is increased by the orifice valve installed in the turbo pump. 5.0x
Adjusted to 10 ^-3 Torr. Next, the microwave power supply 166 is driven to apply microwaves to the vacuum chamber 132.
To generate microwave ECR plasma, and further apply a high-frequency voltage to the substrate to reduce the self-bias voltage −
The lower protective film (silicon nitride film) was etched at 300 V for 10 minutes.

After completion of the etching, the self-bias voltage is
While continuously applying a high frequency voltage of 300 V, a mixed gas of methane and trimethylamine (N (CH ₃ ) ₃ ) is introduced so that the pressure in the vacuum chamber 132 becomes 5.0 × 10 ⁻³ Torr, and plasma CVD is performed. Was performed to produce a thermal head having a 1 μm-thick CN protective film 90 formed thereon as an upper protective film. Further, in exactly the same manner, a thermal head in which a CN protective film 90 having a thickness of 2 μm and 3 μm was formed as an upper protective film was also manufactured. The film thickness of the C—N protective film 90 was controlled in advance by calculating the film forming speed in advance, calculating the film forming time to achieve a predetermined film thickness, and controlling the film forming time.

<Evaluation of Performance> Using the three types of thermal heads and the heat-sensitive material, the same performance evaluation as in Example 1 was performed by the heat-sensitive recording apparatus shown in FIG. As a result, in each of the thermal heads, cracking and peeling of the CN protective film 90 did not occur, and almost no wear was observed. The composition of the obtained C—N protective film 90 was changed to H
As a result of analysis by FS, the composition was N / C = 0.7.

Comparative Example 3 A thermal head was manufactured in the same manner as in Example 2 except that a carbon protective film containing no nitrogen was formed instead of the CN protective film 90. Specifically, a carbon protective film was produced basically in the same manner as in Example 2 except that only methane gas was used as a reaction gas. For this thermal head, the same performance evaluation as in Example 2 was performed. As a result, the cracking or peeling of the CN protective film 90 occurred before the recording of 5000 sheets was completed.

Comparative Example 4 A thermal head was fabricated in the same manner as in Example 2 except that a protective film containing fluorine in addition to nitrogen and hydrogen was formed instead of the CN protective film 90. . Specifically, in addition to the plasma generation gas, methane and trimethylamine (N (C
A protective film was produced basically in the same manner as in Example 1 except that a mixed gas of H ₃ ) ₃ ) and C ₂ F ₆ was introduced. For this thermal head, the same performance evaluation as in Example 2 was performed. As a result, the wear amount was about 5
It has doubled. Further, the composition of the obtained protective film was changed to H
As a result of analysis by FS, the composition was N / C = 0.2. From the above results, the effect of the present invention is clear.

[0087]

As described in detail above, according to the present invention, corrosion and wear of the protective film are extremely small, and furthermore, cracking and peeling of the protective film can be suitably prevented by heat and mechanical shock. By preventing the thermal head, a thermal head having sufficient durability and capable of stably performing high-quality thermal recording over a long period of time can be realized. In particular, it has sufficient durability even in applications where recording under high energy and high pressure is used for heat-sensitive films that use highly rigid supports such as polyester films used in medical applications, etc. High reliability can be demonstrated over

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of an example of a thermal recording apparatus using a thermal head of the present invention.

FIG. 2 is a schematic diagram showing a configuration of a heating element of the thermal head of the present invention.

FIG. 3 is a conceptual diagram of an example of a sputtering apparatus for forming a CN protective film of a thermal head according to the present invention.

FIG. 4 is a conceptual diagram of an example of a film forming apparatus for forming a CN protective film of a thermal head according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 (Thermal) recording device 14 Loading part 16 Supplying and conveying means 20 Recording part 22 Discharge part 24 Magazine 66 Thermal head 80 Substrate 82 Glaze layer 84 Heat generation (resistance) body 86 Electrode 88 Lower protective film 90 CN protective film (Upper protective film) 100) Sputtering apparatus 102, 132 Vacuum chamber 104, 134 Gas introduction unit 106 Sputtering means 108, 144 Substrate holder 110, 146 Vacuum exhausting means 112, 148, 156 Cathode 114, 150 Target material 116, 152, 158 Shutter 118, 154 , 160 DC power supply 120, 162, 164 Backing plate 122, 142 Bias power supply 130 Film forming apparatus 136 First sputtering means 138 Second sputtering means 140 Plasma generation means 166 Microwave Source 170 microwave introducing pipe 172 coaxial converter 174 dielectric plate 176 radially antenna 180 rotates the substrate A heat-sensitive material

Claims (2)

[Claims] 1. A thermal head having a heating resistor on a substrate, the heating head comprising carbon and nitrogen as main components on the heating resistor.
Alternatively, a thermal head further comprising a protective film containing hydrogen. 2. The thermal head according to claim 1, wherein at least one lower protective film mainly composed of ceramics is provided between the heating resistor and the protective film.