JPH0347757A - Method of forming metal organic material film on thermal head - Google Patents

Abstract

PURPOSE:To prevent an unnecessary metal organic material film from remaining on the surface of an insulating substrate by a method wherein a removable coating layer provided with a film forming groove is formed on the surface of the insulating substrate, and a film forming material made of a metal organic material is applied to the film forming groove and dried. CONSTITUTION:On the surface of an insulating substrate 2, a tape 20 (a removable coating layer) is attached. A film forming groove 21 is provided between the tapes so as to be positionally corresponding to a partial under glaze 2b. A metal organic material 22 for forming heating resistors is applied and dried, and it is burned after the tape is removed to form a belt-form resistor film 3'. Thereafter, a resist pattern for forming heating resistors is formed and etched to obtain a pattern of heating resistors 3. A metal organic gold paste is solid printed and burned to form an electrode film 4'. A common electrode 4 and discrete electrodes 5 are formed using a resist pattern RP2. A metal organic material for forming a wear resistant layer is solid printed by screen printing.

Description

Detailed Description of the Invention A0 Object of the Invention l) Industrial Field of Application The present invention is directed to the surface of an insulating substrate of a thermal head used in a thermal printer or facsimile machine as an output device of a word processor, personal computer beater, etc. The present invention relates to a method of forming a resistive film for forming the heat generating resistor or an electrode film for forming the electrode on the surface of the insulating substrate in the process of forming the heat generating resistor or electrode.

2) Prior art The thermal head has low noise during printing, and
It has the advantage of being easy to handle because it does not require a developing/fixing process, and has been widely used.

In the manufacturing process of the thermal head, a thick film paste along the main scanning direction is applied in a belt shape on the surface of an insulating substrate using a thick film technique such as screen printing, dried, and fired to form a belt-shaped heating resistor. Thick a! ! ! A thin film in which multiple individual heating resistors are formed along the main scanning direction using photolithography on a thermal head and a resistive layer formed on the entire surface of an insulating substrate using thin film techniques such as vapor deposition and sputtering. type thermal head is known.

3) Problems to be Solved by the Invention The thick-film thermal head using the band-shaped heating resistor has the following problems:
The equipment is inexpensive and productivity is high (4), but the film thickness of the electrode and heating resistor is thick, so the heat capacity of the heating element is large and the thermal response is poor, and the heating resistor is made of powder on the order of μm. Since it is a sintered body, there is a problem in that the resistance value varies widely. In addition, the electrode density is the density of the heating element (
That is, since it is necessary to form the heating elements at a density twice that of the printed dots, there is also the problem that it is difficult to increase the density of the heating elements.

In addition, the Fi1Mm thermal head can form electrodes, heating resistors, and wear-resistant layers with uniform compositions, and the arrangement density of the electrodes and heating resistors may be the same as the density of the heating elements, so that uniform high-temperature Although it is possible to obtain printed dots with high density, there is a problem in that the manufacturing equipment becomes large-sized and the cost increases.

Therefore, the present applicant first developed a method for manufacturing a thermal head having the advantages of a thin film type thermal head using an inexpensive thick film technology of manufacturing equipment, that is, MOD (M
etallo Organized Deposit
on) is proposing a law.

In this MOD method, the resistance layer for forming the heat generating resistor is made of a small amount of metal (M) selected from a group of elements such as ruthenium (Ru), iridium (Ir), or rhodium (Rh), silicon (Si), It is formed by applying a metal growth material containing elements such as barium (Ba), bismuth (Bi), lead (Pb), etc. to a substrate and drying it. For example, a method using a spin coater is employed.The resistive layer formed on the entire surface of the substrate is fired by such a method, and then the heating resistor is formed by photolithography.

By the way, when forming a partial underglaze on the surface of an insulating substrate, if a full underglaze layer is formed on the surface of the insulating substrate and then a partial underglaze is formed on that surface, the shape of the partial underglaze is likely to be distorted. Therefore, when forming a partial underglaze on the surface of an insulating substrate, the partial underglaze is often formed directly on the surface of a ceramic substrate that constitutes the main body of the insulating substrate.

When forming a heating resistor on the partially underglazed surface of such an insulating substrate, a method is adopted in which a resistive film for forming the heating resistor is formed on the entire surface of the insulating substrate, and then this is etched using an etching solution such as hydrofluoric nitric acid. Then, an unnecessary resistive film may remain on the surface of the insulating substrate other than the partial underglaze. This unnecessary residual resistance film forms irregularities on the surface of the insulating substrate, which may impede the formation of a uniform electrode film.

Incidentally, the width of the partial underglaze in the thermal head is approximately 11 mm, and the minimum width required for the resistive film for forming the heating resistor on the surface thereof is approximately 200 μm. Therefore, the convergence on the partial underglaze surface is approximately 1
By forming a resistive film of the seal and etching this resistive film to form a heating resistor, it is possible to prevent unnecessary resistive film from remaining on the surface of the insulating substrate.

As described above, when forming a resistive film for forming a heating resistor on the surface of an insulating substrate that has partial underglaze, it is necessary to It is better to form a resistive film, but even for ceramic ring insulating substrates with no partial underglaze or insulating substrates with full underglaze, it is better to form a resistive film only on the necessary parts of the surface to avoid unnecessary residue. This is often advantageous because there is no risk of forming a resistive film, and depending on the film forming means employed, the material for forming the resistive film can be saved.

The above has explained that with regard to the resistive film for forming the heat generating resistor of the thermal head, it is sometimes better to form the resistive film only on the necessary surface area instead of forming it on the entire surface of the insulating substrate. It may be better to form an electrode film for forming an electrode, a film for forming an abrasion resistant layer, etc. only on the necessary surface portion of the insulating substrate.

In view of the above-mentioned circumstances, the present invention aims to prevent unnecessary metal-organic material films from remaining on the surface of an insulating substrate when forming a resistive film, an electrode film, etc. made of a metal-organic material film on the surface of an insulating substrate by the MOD method. That is the issue.

B1 Structure of the Invention l) Means for Solving the Problems In order to solve the above problems, the method for forming a metal-organic material film according to the present invention is a method of forming a metal-organic material film on a predetermined surface portion of an insulating substrate surface of a thermal head. In this step, a removable coating layer having film forming grooves provided at positions corresponding to the predetermined surface portions is formed on the surface of the insulating substrate, a film forming material made of a metal-organic material is applied to the film forming grooves, and then dried. The method is characterized in that a metal-organic material film is formed on the predetermined surface portion.

2) Function The method for forming a metal-organic material film according to the present invention includes forming a removable coating layer on the surface of an insulating substrate, in which a film forming groove is provided at a position corresponding to a predetermined surface portion of the insulating substrate where a film needs to be formed. - applying a film-forming material made of a metal-organic material to the film-forming groove and drying it to form a metal-organic material film on the predetermined surface portion; Therefore, since the metal-organic material film is not formed on areas other than the predetermined surface area,
Unnecessary metal-organic material films are less likely to remain on the surface of the insulating substrate. Furthermore, as described above, since a removable coating layer having film forming grooves at positions corresponding to predetermined surface portions is formed on the surface of the insulating substrate, a film forming material made of a metal-organic material is applied to the film forming grooves. When coating, the film-forming material can be used regardless of whether it is in liquid or paste form.

3) Examples Hereinafter, examples of the method for forming a metal-organic material film of the present invention will be described with reference to the drawings.

1 to 4B are explanatory diagrams of a thermal head manufactured by applying the first embodiment of the method for forming a metal-organic material film of the present invention.

As shown in FIG. 1, a thermal head H for performing thermal recording on a thermal recording paper P conveyed along the outer periphery of a platen roll R is provided with a support plate 1. An insulating substrate 2 is attached to the surface of the support plate 1 on the right side in FIG. 1 with an adhesive. Approximately 1
11h, and a band-shaped partial underglaze 2b having a thickness of about 50 to 60 μm along the main scanning direction.

As shown in FIG. 3, a plurality of heating resistors 3 are provided in the form of islands along the main scanning direction X on the surface of the partial underglaze 2b.

Further, on the surface of the insulating substrate 2, a common electrode 4 is formed of a band-shaped common electrode main body part 4a and a large number of common electrode connection parts 4b protruding from the common electrode main body part 4a in a comb-like shape in the sub-scanning direction Y. A large number of individual electrodes 5 are formed facing the large number of common electrode connecting portions 4b at a predetermined distance. Each of the common electrode connecting portions 4b and the individual electrodes 5 are connected by the heating resistor 3 disposed on the surface of the insulating substrate 2. Further, the base end portion (the left end portion in FIG. 1) of the individual electrode 5 is formed as an IC connection terminal 5a for connection to a driving IC to be described later.

A printed wiring board 6 is attached to the surface of the support plate 1 on the left side in FIG. 1 with an adhesive, and external connection wiring 7 is formed on the printed wiring board 6. This external connection wiring? is connected to a socket 9 as a drive signal input terminal via a lead wire 8 passing through the printed wiring board 6 at its input end side (left side in FIG. 1).
It is connected to the. The insulating substrate 2 of the printed wiring board 6
A driving IC is disposed near a portion thereof, and this driving IC is connected to the IC connection terminal 5a of the individual electrode 5 and the external connection wiring 7 by bonding wires 10 and 11.

The IC and bonding wire 10.11 are covered with a protective resin 12, and the heating resistor 3,
The common electrode 4, individual electrodes 5, etc. are covered with a wear-resistant layer 13 (third
．． (see figures 4A, 4B, 4C).
Note that the wear-resistant layer 13 is omitted in FIGS. 1 and 2. )
. Further, the protective resin 12 is protected by an aluminum ring cover 14.

The thermal head H is composed of the components indicated by the numerals 1 to 14 and the driving IC.

Next, according to FIGS. 5A to 11C, the
A method of manufacturing a thermal head H having the configuration shown in FIG. 40 will be described.

(a) Resistive film forming step (see Figures 5A to 8B) 5A,
The insulating substrate 2 shown in FIG. 5B is composed of an insulating substrate main body 2a made of ceramic and a band-shaped partial underglaze 2b formed along the main scanning direction X on the upper surface of the insulating substrate main body 2a.

A tape 20.20 (removable coating layer) is applied to the surface of this insulating substrate 2, as shown in FIGS. 6A to 6C. Film forming groove 21 formed between this tape 20 and 20
is provided at a position corresponding to the partial underglaze 2b (predetermined surface portion).

A metal-organic material (resistance film forming material) 22 for forming a heating resistor is applied to the surface of the insulating substrate 2 to which the tape 20 is attached to a uniform thickness using a spin coater (
(See figures M7A and 7B).

As the resistive film forming material 22, for example, solutions of the following numbers of Metal Resinate (product name B) manufactured by Engelhard Co., Ltd. are mixed and used.

A-1123 (Ir organic material) #28-FC (Si organic material) #118-B (Sn organic material) That is, the atomic ratio after firing each of the above solutions is Ir
:S i : 5n=l :0.5 :0.3 and then adjusted to an appropriate viscosity using a solvent such as α-terpineol or butylcarpitol acetate. This mixture (resistance film forming material) 22 is applied to the surface of the insulating substrate 2 to a uniform thickness using a spin coater. After drying this insulating substrate 2, the tape 2
When 0.20 is removed, as shown in Figures 8A and 8B,
An unsintered strip-shaped metal-organic material film, that is, an unsintered strip-shaped resistance film 23, is formed on the surface (predetermined surface portion) of the partial underglaze 2b. This unsintered strip resistance wA2
The insulating substrate 2 on which 3 is formed is fired for 10 minutes at a peak temperature of 600 to 800°C in an infrared belt firing furnace to form a sintered metal-organic material film, that is, a strip resistor M3.
(See Figures 8A and 8B).

(11) Resist pattern forming process for forming heating resistor (see 9A, 9B, IOA, 108) Next, 9A
, 9B, the sintered strip resistor [3'
After forming a resist layer R1 thereon, an exposure mask M is placed thereon, and exposure and development are performed. Then, the 1st O
A, a resist pattern RPI for forming a heating resistor as shown in FIG. 108 is obtained.

(8) Heating resistor forming step (see FIGS. 11A and 118) Next, etching is performed using hydrofluoric nitric acid (etching solution) to obtain a pattern for the heating resistor 3.

(d) Gold film forming step (see Figures 12A to 12C) Next,
A metalloorganic gold paste such as 027 manufactured by Noritake Co., Ltd. is printed all over the surface of the insulating substrate 2 on which the heating resistor 3 is formed, and then baked to form a gold electrode film 4'.

(n) Resist pattern formation process for electrode formation (13th
(See figures A to 13C) Next, after forming a resist layer on the electrode film 4',
Resist pattern RP for electrode formation by exposure and development
Get 2.

(f) Electrode formation step (see Figures 14A to 14C) Next,
Etching is performed using an iodine-potassium iodide solution (etching solution) to form a common electrode 4 and individual electrodes 5 from the electrode M4'.

(g) Wear-resistant layer forming step Next, on the surface of the insulating substrate 2 on which the heating resistor 3, the common electrode 4, and the individual electrodes 5 are formed, a gold 11Ilr mechanical material (resistant to Abrasion layer forming material) is printed solidly by screen printing.

As the material for forming the wear-resistant layer, for example, the following solutions of Metal Resinate (trade name) manufactured by Engelhard Co., Ltd. are mixed and used.

#28-FC (Sl organic material) #9428 (TIW mechanical material) #8385 (Bi breeding material) That is, the atomic ratio after firing each of the above solutions is
:Tl :BI = 1 : 1 : 0.5, and further, the viscosity was reduced to 5 using a solvent such as α-terpineol or butylcarpitol acetate.
Adjust to 000 to 30000 cps.W mixture to 1
Print coating is applied onto the insulating substrate surface 2C using a stainless steel screen of 00 to 325 mesh. This printed insulating substrate 2 is dried at 120°C, and then heated to a peak temperature of 600 to 800°C in an infrared belt firing furnace for 10 minutes.
When baked for a minute, a wear-resistant metal-organic material film is formed, but since this film is required to have wear resistance, the steps of applying the wear-resistant layer forming material, drying, and sintering are repeated four times. Finally, a wear-resistant layer 13 (see FIGS. 3 and 4A to 40) having a thickness of 1.6 to 2.0 μm is formed. In this way,
A thermal head H having the configuration shown in FIGS. 4A to 40 is obtained.

According to the first embodiment described above, the removable covering layer 20.2
Since the liquid resistance film forming material 22 is applied by a spin coater to the surface of the insulating substrate 2 in which the film forming grooves 21 are formed in the predetermined surface portion 2b of the insulating substrate 2, the predetermined surface portion 2 of the insulating substrate 2
An extremely thin and uniform resistive film can be formed only on b.

Next, a second embodiment of the method for manufacturing a thermal head according to the present invention will be described with reference to FIG.

This second embodiment is a resist layer 20' in which a film forming groove 21' is formed instead of the tape 20. and the film forming material 2 for forming a resistive film (metal-organic material film) in the film forming groove 21'.
This embodiment differs from the first embodiment in that a dispenser 24 is used as shown in FIG. 15 when applying 2'.

According to the method for forming a metal-organic material film for forming a heat generating resistor according to the second embodiment described above with reference to FIG. You can save money.

Next, a third embodiment of the method for manufacturing a thermal head of the present invention will be described with reference to FIGS. 18A to 21B.

This third embodiment is the same as the first embodiment except for the step (a) of forming a resistive film in the first embodiment described with reference to FIGS. 5A to 11B.

The insulating substrate 2 shown in FIGS. 16A and 188 is composed of an insulating substrate body 2a made of ceramic and a band-shaped partial underglaze 2b formed along the main scanning direction X on the upper surface of the insulating substrate body 2a.

This is the same as the insulating substrate 2 of the first embodiment shown in FIG. 6B.

As shown in FIGS. 17A and 17B, a photoresist is applied to the entire surface of the insulating substrate 2 on which the partial underglaze 2b is formed, and a mask M is placed over the photoresist, followed by exposure and development. As shown in FIGS. 18A to 18C, a resist layer ( That is, a removable coating layer) 20# is formed.

Next, as shown in FIGS. 19A and 19B, a resistive film forming material 22# similar to that of the second embodiment is printed in a band shape along the rows of the openings 21# of the resist layer 20#. ``Fill the opening 21# so that it is higher than the surface and dry it.

Next, 20A, 20BI! As shown in A, the dried resistive film forming material 22# is lapped (ground) to remove the portion above the resist jm20'' surface, and an unsintered resistor ( That is, a metal-organic material film 23' is formed.Next, this unsintered resistor 23' is fired and the resist layer 20'' is removed by combustion. Then, the L/971 cellulose contained in the unsintered resistor 23' is removed by combustion, and as a result, as shown in FIGS. 21A and 21B, the thickness of the unsintered resistor 23' is The heating resistor 3 is formed with a thickness that is smaller than that of the heating resistor 3. It should be noted that FIGS. 21A and 21B are the 11th example of the first embodiment.
This is the same as Figures A and 11B.

Although the embodiments of the thermal head and the method for manufacturing the same according to the present invention have been described in detail above, the present invention is not limited to the above-mentioned embodiments, and there is no deviation from the scope of the present invention as set forth in the claims. , it is possible to make various minor design changes.

For example, as a method for applying the metal-organic material to the surface of the insulating substrate, it is also possible to employ a printing method using a mesh screen, a dip method, a roll coating method, or the like. In addition, all 1 items are available only on the specified surface area! ! The method of applying the film-forming material for forming the growth material film is applicable not only to the metal-organic material film for forming the heat-generating resistor, but also to the application of the film-forming material for forming the electrode and wear-resistant layer. It is also possible to apply it to I-culture material films.

The present invention also applies the metal-organic material to a predetermined surface portion of a ceramic insulating substrate on which an underglaze is formed on the entire surface or a ceramic insulating substrate on which neither an entire underglaze nor a partial underglaze is formed on the surface. It is possible to apply a method of forming a film. Also, gold jli! Since the temperature at which the nursery material is fired is relatively low, it is also possible to use heat-resistant glass, which has a lower temperature limit than ceramic, as the insulating substrate.

Instead of using Engelhard's metal resinate as the metal-organic material for forming the heating resistor, we used a metal-organic material in which the metal formed a complex with an organic substance such as a carboxylic acid, which is soluble in the growth solvent. It is possible to use various metal-organic materials, if any. Also,
Similarly, it is possible to use materials other than those shown in the above embodiments as the metal organic material for forming the electrodes and the metal *a material for forming the wear-resistant layer.

C6 Effects of the Invention The method for forming a metal-organic material film of the present invention described above is a method for forming a metal-organic material film on a predetermined surface portion of the surface of an insulating substrate of a thermal head. A removable coating layer provided with is formed on the surface of the insulating substrate, and a film-forming material made of a metal-organic material is applied to the film-forming groove and then dried to form a metal-organic material film on the predetermined surface portion. Therefore, the metal-organic material film is not formed on areas other than the predetermined surface portion. Therefore, when forming the metal-organic material film into a predetermined pattern by photolithography, unnecessary metal-organic material film is less likely to remain on the surface of the insulating substrate. Furthermore, as described above, since a removable coating layer having film forming grooves at positions corresponding to predetermined surface portions is formed on the surface of the insulating substrate, a film forming material made of a metal-organic material is applied to the film forming grooves. When coating, the film-forming material may be in liquid or paste form.

Metal-organic material films can be formed into thin films that are homogeneous at the atomic level using thick film technology, so the resistance value of the heating resistor can be reduced without using the large manufacturing equipment used in thin film technology. It becomes possible to obtain a thermal head with small variations.

[Brief explanation of drawings]

FIG. 1 is an overall explanatory diagram of a thermal head manufactured by applying the first embodiment of the metal-organic material film forming method of the present invention, FIG. 2 is a perspective view of the main part of the same embodiment, and FIG. 2, FIG. 4A is a plan view of the main part of the same embodiment as seen from arrow 4A in FIG. 3, and FIG.
4C is a sectional view taken along the line 4C-4C of FIG. 4A, FIGS. 5A to 14C are explanatory views of the method for manufacturing the thermal head, and FIG. 15 is a sectional view of the metal-organic material film formation of the present invention. 16A to 21B are explanatory diagrams of a second embodiment of the method, and FIGS. 16A to 21B are explanatory diagrams of a third embodiment of the method for forming a metal-organic material film of the present invention. 2...Insulating substrate, 2b...Partial underglaze (
Predetermined surface portion), 20.20'20#... Covering layer, 21.21', 21"... Film forming groove, 22.22
'22#... Film forming material (resistance film forming material), 3'2
3.23'...Metal-organic material film Fig. 4C 1? Figure 4A Figure 8A □Y N a Figure 8B Figure 10A □Y N Figure 10B Figure 7A □ Y Figure 7B Figure 9A Figure 9B Figure M 7℃ 1 Figure 13A Figure 15 Figure 17A Figure 178 Figure 21A Figure 1+-Y Figure 21B'' Figure 16A Figure 16B f2oA Figure □Y Figure 20B Figure 19A Figure 19B

Claims (1)

[Claims] A predetermined surface portion of the insulating substrate (2) surface of the thermal head (
2b), in which a film forming groove (21, 21', 21'') is provided at a position corresponding to the predetermined surface portion (2b). A removable coating layer (20, 20', 20'') is formed on the surface of the insulating substrate (2), and the film forming groove (21, 21') is formed on the surface of the insulating substrate (2).
, 21″) is coated with a film-forming material (22″) made of a metal-organic material.
, 22', 22'') is applied and dried to form a metal-organic material film (3', 23, 22'') on the predetermined surface portion (2b).
3') A method for forming a metal-organic material film for a thermal head.