JPH1034990A - Thermal head - Google Patents

Thermal head

Info

Publication number
JPH1034990A
JPH1034990A JP19060896A JP19060896A JPH1034990A JP H1034990 A JPH1034990 A JP H1034990A JP 19060896 A JP19060896 A JP 19060896A JP 19060896 A JP19060896 A JP 19060896A JP H1034990 A JPH1034990 A JP H1034990A
Authority
JP
Japan
Prior art keywords
layer
conductive layer
heating resistor
thermal head
protective layer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
JP19060896A
Other languages
Japanese (ja)
Inventor
Riyuuichi Utsuka
竜一 兎束
Original Assignee
Toshiba Corp
株式会社東芝
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toshiba Corp, 株式会社東芝 filed Critical Toshiba Corp
Priority to JP19060896A priority Critical patent/JPH1034990A/en
Publication of JPH1034990A publication Critical patent/JPH1034990A/en
Abandoned legal-status Critical Current

Links

Abstract

(57) [Problem] To provide a thermal head that prevents dielectric breakdown of a protective layer. SOLUTION: A support base 1, a heating resistor layer 13 formed on the support base 11, an electrode layer 14 formed on the heating resistor layer 13, and at least a heating portion of the heating resistor layer 13 Electrically insulating protective layer 15 covering 13a
And the conductive layer 16 formed on the protective layer 15, the conductive layer 16 has a thickness of 3A to 7A.
It is made of at least one metal element selected from Group A and a cermet containing silicon and oxygen as main components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head having an antistatic conductive layer provided on a protective layer so that the protective layer does not undergo dielectric breakdown.

[0002]

2. Description of the Related Art Thermal heads have advantages such as low noise, easy maintenance, and low running cost, and are used in various types of recording apparatuses such as facsimile machines and word processors. Further, thermal heads for video printers have become widespread, and accordingly, thermal heads using a thermal transfer ribbon have been used. The thermal transfer ribbon is made of polyethylene terephthalate (hereinafter referred to as PET).
Etc. are coated with a paint that is thermally transferred onto a toner film.

Here, a conventional thermal head is described as follows.
A description will be given with reference to FIG. Reference numeral 21 denotes a ceramic support base made of alumina or the like, on which a glaze layer 22 is formed. A heating resistor layer 23 is formed on the support base 21 and the glaze layer 22. The heating resistor layer 23 is formed of TaSiO, NbSiO, or the like, and constitutes a large number of resistors arranged in an array. Further, an electrode layer 24 is formed on the heating resistor layer 23. The electrode layer 24 constitutes a common electrode or an individual electrode. When printing, a predetermined resistor is selected from a large number of resistors constituted by the heating resistor layer 23, and a current is supplied to the selected resistor. It is configured to supply and generate heat. When a current is supplied from the electrode, the resistor sandwiches the heat generating portion 2 in the region sandwiched by the electrode layers 24.
Heat is generated as 3a. Further, a protective layer 25 is formed on the heating resistor layer 23 and the electrode layer 24. Protective layer 25
Is formed of an electrically insulating material such as SiON having excellent wear resistance and oxidation resistance, and covers at least the heat generating portion 23a of the heat generating resistor layer 23.

Reference numeral 26 denotes an ink sheet obtained by applying ink to PET, and the ink sheet 26 is an image receiving paper 27.
Is in contact with The ink sheet 26 and the image receiving paper 27 are wound around a platen 28 and rotate in the direction of the arrow Y while being pressed against the heat generating portion 23a of the heat generating resistor layer 23 constituting the thermal head. At this time, printing is performed on the image receiving paper 27 by the heat of the heat generating portion 23a.

The ink sheet 26 and the protective layer 25
Are made of an electrically insulating material, and both are in contact with each other and are in a rubbed state. For this reason, static electricity is generated at the contact portion. The generated static electricity charges the protection layer 25 and induces charges of different signs in the electrode layer 24 and the heating resistor layer 23 or generates a high electric field inside the protection layer 25. At this time, if the electric field inside the protective layer 25 increases, the dielectric strength of the protective layer may be exceeded, and dielectric breakdown occurs in the protective layer 25. As a result, the function of the protective layer is lost, or the thermal head is destroyed.

[0006]

Various methods have been attempted to prevent dielectric breakdown of the protective layer. For example, there is a method in which a conductive layer such as Cr or TiN is deposited on the protective layer (see JP-A-7-266594). The conductive layer disperses electrostatic charges, thereby preventing dielectric breakdown of the protective layer. However, Cr and TiN are inferior in wear resistance and require a thickness of 10 μm or more in order to secure practical life characteristics. Therefore, it takes time to form the conductive layer, and the productivity is reduced.

Another method is to provide a conductive layer in a protective layer (see JP-A-3-81161). This is a method in which a silicon nitride layer is deposited to a thickness of 4 μm, a Cr layer is formed thereon, and a silicon nitride layer is deposited to a thickness of 1 μm on the Cr layer. in this case,
Since the Cr layer only needs to release charges, it functions even with a thickness of about 0.1 μm. However, formation of a Cr layer,
Then, the number of steps such as the deposition of a silicon nitride layer on the Cr layer increases, and the productivity decreases. Also, unless the position of the conductive layer is accurately controlled, a sufficient function of preventing dielectric breakdown cannot be obtained,
High precision is required for forming the conductive layer.

Further, there is a method in which the protective layer itself has conductivity without forming a conductive layer for preventing static electricity (Japanese Patent Laid-Open No. Hei 3-
272868). This is a method in which CuOx or Si is added to a composition composed of LaSiON to give conductivity to the protective layer. However, when the protective layer is made conductive,
The problem is the electrical insulation between the adjacent heating resistor layers.
In addition, a problem of ionic conductivity and electrolytic corrosion occurs.

An object of the present invention is to solve the above-mentioned drawbacks, and an object of the present invention is to provide a thermal head which prevents dielectric breakdown of a protective layer.

[0010]

SUMMARY OF THE INVENTION The present invention provides a support substrate,
A heating resistor layer formed on the supporting base, an electrode layer formed on the heating resistor layer, and an electrically insulating protective layer covering at least a heating portion of the heating resistor layer;
In a thermal head including a conductive layer formed on the protective layer, the conductive layer is made of at least one metal element selected from groups 3A to 7A and a cermet containing silicon and oxygen as main components. ing.

The metal element is Ta or Nb.

The conductive layer has a thickness of 0.2 to 0.6 μm.
m.

The specific resistance of the conductive layer is 1 to 50 mΩ.
cm.

The composition of the conductive layer is Ta or Nb.
Is in the range of 20 to 40 atm%, the balance is substantially silicon and oxygen, and the value of the atm% ratio of silicon to oxygen is 1/2 to 2
The range is 1/3.

According to the above-described structure, the cermet forming the conductive layer contains one or more refractory metals selected from the group 3A to 7A, silicon and oxygen as main components, and has a conductive property necessary for antistatic. Properties and excellent wear resistance. Therefore, even if the thickness of the conductive layer is not increased, it is not worn out within a period required for practical use,
Further, dielectric breakdown does not occur in the conductive layer. Also,
The thickness of the conductive layer can be reduced, and the material of the conductive layer can be shared with the heating resistor layer, which is advantageous in terms of productivity and cost.

The conductive layer has a thickness of 0.2 to 0.6 μm.
And If it is thinner than 0.2 μm, it will wear faster,
In addition, electrostatic breakdown or the like occurs, and the time during which operation can be reliably performed is shortened. When the thickness is more than 0.6 μm, the strength against abrasion increases. However, as the thickness increases, the time required for forming the conductive layer becomes longer, and the required raw materials also increase, which is disadvantageous in terms of productivity and cost. In addition, the more preferable thickness of the conductive layer is in the range of 0.3 to 0.5 μm.

The specific resistance range of the conductive layer is 1 to 50 mΩ.
・ Cm. If it is less than 1 mΩ · cm, the abrasion resistance is inferior and a sufficient life cannot be obtained. Also, 50mΩ · cm
If it is larger, the problem of abrasion resistance and antistatic property will be eliminated, but it will be difficult to make it common with the step of forming the heating resistor layer. For example, if it exceeds 50 mΩ · cm, the resistance value of the heating resistor layer will vary, and the temperature coefficient of resistance will increase sharply, making its control difficult. Therefore, when forming the conductive layer, the film formation conditions such as the composition of the sputtering target are set so that the specific resistance is 50 mΩ · cm or less. The more preferable range of the specific resistance is 2 to 4
0 mΩ · cm.

The composition of the conductive layer is Ta or Nb.
Is in the range of 20 to 40 atm%.
If it exceeds 40 atm%, the metal component becomes excessive and the abrasion resistance becomes insufficient. In addition, when it is less than 20 atm%,
Depending on the film forming conditions, a sufficient antistatic function may not be obtained. In addition, a more preferable composition range is 15 to 35a.
tm%. The balance other than the metal component is substantially composed of silicon and oxygen. In this case, the atm% ratio between silicon and oxygen is set to silicon / oxygen = 1/2 to 1/3. If the thickness is outside this range, the abrasion resistance of the conductive layer will deteriorate, and it will be difficult to use the same process as forming the heating resistor layer.

The conductive layer having the above-described specific resistance and composition ranges is made of, for example, 45 to 65 mo of Ta or Nb.
It can be formed by performing sputtering in an Ar gas atmosphere using a sintered body target whose balance is substantially made of SiO 2 at 1%. Further, this process can be used for forming the heating resistor layer as it is, and the steps can be shared.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. Reference numeral 11 denotes a ceramic support base such as alumina, on which a glaze layer 12 is formed. Support base 1
The heating resistor layer 13 is provided on the first and glaze layers 12. The heating resistor layer 13 is made of TaSiO, NbSiO, or the like, and constitutes a large number of resistors arranged in an array.

An electrode layer 14 is provided on the heating resistor layer 13. The electrode layer 14 constitutes a common electrode commonly connected to a large number of resistors constituted by the heating resistor layer 13 and individual electrodes individually connected to the large number of resistors. When printing is performed, a predetermined resistor is selected from a large number of resistors, and current is supplied to the selected resistor to generate heat. When a current is supplied from the electrode, the resistor generates heat in the electrode layer 14, that is, a region sandwiched between the common electrode and the individual electrode becomes a heat generating portion 13a.

A protective layer 15 is formed on the heating resistor layer 13 and the electrode layer 14. The protective layer 15 is made of SiON
An electrically insulating material such as is used to cover at least the heat generating portion 13a of the heat generating resistor layer 13.

A conductive layer 16 for preventing static electricity is provided on the protective layer 15. The conductive layer 16 is made of, for example, TaS
It is formed of the same material as the heat generating resistor layer 13 such as iO or NbSiO, and has a specific resistance of 50 mΩ · c so as to prevent charging.
m or less. Therefore, there is no need to connect the conductive layer 16 to an electrode or the like to release the charge. However, it is also possible to adopt a configuration in which the charge is released by connecting to the common electrode or the individual electrode formed by the electrode layer 14.

Here, a method of manufacturing a thermal head having the above-described structure will be described with reference to the reference numerals shown in FIG. First, a heating resistor layer 13 of TaSiO is formed by a sputtering method on the support base 11 on which the glaze layer 12 is partially provided. Then, the heating resistor layer 13
An Al electrode layer 14, that is, an individual electrode or a common electrode, is formed thereon by a predetermined patterning using a sputtering method or a vapor deposition method and a photoengraving process.

Further, the heating resistor layer 13 is formed so as to cover at least the heating portion 13a of the resistor constituted by the heating resistor layer 13.
The ON protective layer 15 is formed by a sputtering method. After forming the protective layer 15, an antistatic conductive layer 16 is formed on the protective layer 15 by a sputtering method so as to cover at least the heat generating portion 13a of the resistor. At this time, when the same TaSiO as the heat generating resistor layer 13 is used as the conductive layer 16, the step of forming the conductive layer 16 can use the sputtering apparatus and the process of forming the heat generating resistor layer 13 as they are. When the conductive layer 16 is patterned, for example, mask sputtering is used. However, depending on the shape of the patterning, there is a method in which the conductive layer 15 is formed by sputtering over the entire surface and then patterned by a photoengraving process. Thereafter, the resistance value of the resistor is made uniform by an electric trimming method, and a thermal head is completed through a mounting process.

Using the above method, the thickness of the antistatic conductive layer is 0 (none), 0.1, 0.2, 0.
4, 0.6, 0.8 μm and resolution of 150 dp
A sublimation type thermal transfer type thermal head was manufactured and incorporated into a video printer, and an actual machine test was performed.

At this time, those having no conductive layer are 3
At the time of printing of 00 sheets, the protective film caused electrostatic breakdown and could not withstand use. When the thickness of the conductive layer was 0.1 μm, electrostatic breakdown occurred in 3050 sheets. At this time, the conductive layer was worn out and disappeared. The thickness of 0.2 μm is 509.
It can print up to 0 sheets, and is a useful life index of 500
Crossed zero. Any of the sheets having a thickness of 0.4 μm or more did not cause any problem even after printing 6,000 sheets.
However, when the thickness of the conductive layer exceeds 0.6 μm, it takes a long time to form the conductive layer due to the increase in the thickness of the conductive layer, and
Since more materials are required, productivity is reduced and costs are increased. Therefore, the quality is considered to be excessive. Even if the thickness is 0.2 μm, if the specific resistance is less than 1 mΩ · cm or if the metal composition exceeds 40 atm%, 500
In many cases, zero printing cannot be performed.

In the above-described embodiment, an example is described in which the same material is used for the heating resistor layer and the antistatic conductive layer. However, these materials need not be the same, for example, the heating resistor layer is made of NbSiO and the conductive layer is made of Tb.
A combination of aSiO can also be used.

[0029]

According to the present invention, a thermal head in which dielectric breakdown of the protective layer is prevented can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating an embodiment of the present invention.

FIG. 2 is a schematic sectional view illustrating a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Support base 12 ... Glaze layer 13 ... Heating resistor layer 14 ... Electrode layer 15 ... Protective layer 16 ... Conductive layer

Claims (5)

[Claims]
1. A supporting base, a heating resistor layer formed on the supporting base, an electrode layer formed on the heating resistor layer, and an electric power covering at least a heating portion of the heating resistor layer. In a thermal head including an insulating protective layer and a conductive layer formed on the protective layer, the conductive layer includes one or more metal elements selected from Groups 3A to 7A, silicon, and oxygen. A thermal head comprising a cermet as a main component.
2. The thermal head according to claim 1, wherein the metal element is Ta or Nb.
3. The thermal head according to claim 1, wherein the thickness of the conductive layer is in the range of 0.2 to 0.6 μm.
4. The conductive layer has a specific resistance of 1 to 50 mΩ · cm.
3. The method according to claim 1, wherein
The described thermal head.
5. The conductive layer has a composition of Ta or Nb of 2
In the range of 0 to 40 atm%, the balance is substantially silicon and oxygen, and the value of the atm% ratio of silicon to oxygen is 1/2 to 1/1.
3. The range of claim 3, wherein
The thermal head according to any one of the above.
JP19060896A 1996-07-19 1996-07-19 Thermal head Abandoned JPH1034990A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP19060896A JPH1034990A (en) 1996-07-19 1996-07-19 Thermal head

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP19060896A JPH1034990A (en) 1996-07-19 1996-07-19 Thermal head

Publications (1)

Publication Number Publication Date
JPH1034990A true JPH1034990A (en) 1998-02-10

Family

ID=16260908

Family Applications (1)

Application Number Title Priority Date Filing Date
JP19060896A Abandoned JPH1034990A (en) 1996-07-19 1996-07-19 Thermal head

Country Status (1)

Country Link
JP (1) JPH1034990A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7791625B2 (en) 2007-11-30 2010-09-07 Tdk Corporation Thermalhead, method for manufacture of same, and printing device provided with same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7791625B2 (en) 2007-11-30 2010-09-07 Tdk Corporation Thermalhead, method for manufacture of same, and printing device provided with same

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