JPS5970588A - Manufacture of laminate ceramic thermal head - Google Patents

Abstract

PURPOSE:To produce a thermal head which is compact, low in cost, excellent in resolution and high in reliability, by a method wherein resistors and conductors are provided on green sheets of an insulator, wiring is so provided that the conductors are exposed to the exterior for each layer, the resistors are formed by green sheets, and the sheets are laminated in the direction of thickness to form a heating element layer. CONSTITUTION:By using slurries obtained by dispersing an insulator powder and a resistor powder into organic vehicles, the green sheets 1 of the insulator and green sheets of the resistor are produced by a casting method. The green sheets 1 are punched to a predetermined size, conductor patterns 2 are printed thereon by using a conductor paste, and resistors 3 punched into predetermined forms are adhered to predetermined positions. The green sheets 1 with the conductors 2 and the resistors 3 provided thereon and the green sheets 1 alone are laminated on each other, and are pressure-bonded to each other by a heat press to produce a green laminate body. The green laminate body is cut into a predetermined form, thereafter it is sintered through a binder-removing step, and external lead-out electrodes are provided by baking to obtain a laminate ceramic thermal head.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ceramic thermal head, and more particularly to a method for manufacturing a ceramic thermal head in which an insulating material, a heating element material, and a conductive material are integrated and sintered.

Conventionally, →)”-maru heads for thermal recording use a thick film method.

By thin film method or thin film, IjV film mixed method, etc.
It is formed on a ceramic substrate and has been put into practical use.

The conventionally used thermal head is a thick film type.

Each thin film type had advantages and disadvantages. In other words, in the case of a thick film type, large dimensions can be made relatively inexpensively, but since the 2-pole heating element is produced using the J'F film printing method,
There was a resolution limit of 1rlJ, and the limit was 8 tod/dragon. Furthermore, in order to reduce the resolution by reducing the thickness to 11, it is necessary to miniaturize the wiring pattern, so gold must be used as a conductor, and the cost 1 is non-"R".
+ It also had the disadvantage of being expensive. Furthermore, since multilayer wiring is performed at a high density, the yield is poor and the cost is increased.

Furthermore, with the thick film type, the resistance variation of the heating element becomes large because it is difficult to control the printing thickness, and even a very good resistance variation is about ±20, which causes problems with the recording quality when used as a head. there were.

In addition, thermal heads using the thin film method can form fine patterns, so resolution can be improved, but large dimensions are required to make them, and the manufacturing process is complicated, resulting in high costs. There was a problem with wear resistance because the layer was thin.

In addition, multilayer wiring is difficult for →normal heads using the thin film method, which reduces yield due to the occurrence of pinholes in the multilayer wiring, increases the wiring resistance of the multilayer wiring, and causes problems such as element heat generation and drive circuits. Ta.

The present invention solves all of these problems and provides a method for manufacturing a thermal head that is small, low cost, and has low resolution Ji and high reliability.

That is, the present invention includes a process of forming a raw insulator sheet and a raw resistor sheet, a process of forming a conductor layer on the raw insulator sheet, a process of cutting the raw resistor sheet into a predetermined shape, and an insulator with the conductor layer formed thereon. A step of adhering to the surface of the body sheet to form a resistor layer, a step of laminating and pressing the insulator raw sheet on which the resistor layer and the conductor layer have been formed and the insulator raw sheet to form a laminate, and a step of forming the laminate into a predetermined shape. 11 ♀
r; This is a method for manufacturing a multilayer ceramic thermal head.

A thermal head must have more than 1,000 resistors of uniform shape and resistance value arranged in a horizontal row at minute intervals, and must also have the same number of lead wires as resistors at the same density. Moreover, if any one of these resistors or lead wires becomes defective, the head cannot be used.

The present invention forms a resistor and a conductor on a raw insulator sheet, and furthermore, the conductor is wired to the outside in each layer.The density of the wiring is actually made finer than the conventional method in which the density of the wiring is made finer within the same plane. We were able to significantly improve the interconnect density and the reliability of the interconnect.

Furthermore, since the heating element layer is formed by forming the resistor from raw sheets 1 and laminating them in the thickness direction, the thickness of the resistor layer can be reduced to several tens of microns.

As a result, it became possible to make the resolution of the thermal head equivalent to that of the thin film type head.

In addition, in conventional thermal heads, the thickness of the resistor layer formed by either thick-film or thin-film methods ranges from several thousand on-guest fans to several tens of microns, resulting in poor wear resistance and poor usage conditions. In many cases, the resistor layer was worn out.

7 For this reason, conventional thermal heads are coated with wear-resistant glass, Ta, 0. Abrasion-resistant layers such as these were formed to a thickness of several tens of microns.

However, when these wear-resistant layers are formed, when heat from the resistor/heating element is conducted to the wear-resistant layer, heat diffusion in the lateral direction occurs simultaneously in the thickness direction, which causes resolution to deteriorate. Ta.

In this way, conventional thermal heads are thick-film type.

Both the thin film method and the mixed method have their own problems.

The present invention solves these problems and provides a high-performance, low-cost thermal rad that can be mass-produced by using a structure that is completely different from the conventional one.

The present invention will be described in detail below with reference to drawings and examples.

FIG. 1 is a perspective view showing an example of the structure of a thermal head 41 manufactured by the manufacturing method of the present invention, in which 1 is a resistor layer exposed on the surface, 2 is an insulator, and 3 is an external electrical signal. t! for external connection to input ! It shows the pole.

In this figure, the resistor 2 is made of completely integrated ceramic.

Figure 2 shows a cross section of the above-mentioned legal head, where (a) shows the cross section taken along the dotted line in Figure 1, and (1)) also shows the dotted line in Figure 1. It was cut at the part (Prayer 1f11 is shown 1y-C. Figure 2 (
1 in a) is a resistor, 2 is an insulator, and 4 in FIG. 2(b) is an internal conductor.

As is clear from FIGS. 1 and 2, in the normal head according to the structure of the present invention, the heating resistor is embedded in the insulator, so wear of the resistor is prevented by the insulation. It is protected by the body and has a sufficiently wear-resistant structure even without a wear-resistant layer on the surface. Furthermore, since most of the resistor is embedded within the insulator, the structure is such that the resistor never becomes disconnected. Therefore, since there is no diffusion of heat through the wear-resistant layer, a resolution approximately equal to the thickness of the resistor can be obtained. Furthermore, in conventional thermal heads, when current flows inside the resistor and generates heat, the resistor has a width, and the heat generation varies depending on the location due to the variation in the resistor's warp within that width. 5, unevenness often occurred in the recorded images.

According to the structure of the present invention, since the resistor has a structure in which the thickness direction is exposed at the surface, the heat within the same dot becomes uniform and density unevenness is reduced. Furthermore, as will be described in detail later in the manufacturing process of this embodiment, in the thermal head of the present invention, a uniform resistor is formed by a method of pasting a resistor raw sheet on a uniform insulator raw sheet, so that the thickness of the resistor The thickness of the resistor can be uniformly formed from tens of microns to hundreds of microns, and the raw insulator sheet can be uniformly formed from tens of microns to hundreds of microns, so the thickness of the resistor and the pitch of the resistor can be made very fine. It is possible to increase the recording resolution from the conventional 6 to 8 tod/mu to several tens of tod/mu,
5. I can improve my skills dramatically.

Next, the manufacturing method of the present invention will be explained with reference to the drawings.

FIG. 3 shows a process diagram of the manufacturing process of the present invention.

To explain this manufacturing method with reference to FIG. 3, first, an insulator powder and a resistor powder are each dispersed in an organic vehicle to form a slurry. A raw insulator sheet and a raw resistor sheet are made from these slurries by a casting method using a doctor blade.

This raw insulator sheet is punched out to a predetermined size, and a conductive pattern is printed using conductive paste.

After punching the resistor raw sheet into a predetermined shape on the insulating clean sheet on which the conductor has been formed, the raw insulating sheet is tightened at a predetermined position.

A conductor is formed in this manner, and a required number of insulator green sheets with resistors added thereto, as well as only the insulator green sheets, are laminated and pressed together using a hot press to form a green laminate.

After the raw laminate is cut into a predetermined shape, it is sintered after a binder removal process, and the external electrodes are burnt out to form a laminated ceramic thermal head.

Due to this manufacturing method, the film thickness of the insulating raw sheet and the resistor raw sheet can be formed in a wide range from 10 ttm to 1000 ktnl, so the thickness of the resistor after sintering, The distance between the resistor and the resistor is 8 μm to 8
00μInKichi You can freely choose from a wide range of options. In particular, by reducing the thickness of the resistor and the insulator, it is possible to achieve a resolution of several tens of tods/rum or more.

The wiring necessary for heating the resistor to 4i-heat can be formed three-dimensionally using the sophisticated wooden construction method.
Very advanced thick film like conventional wiring; 1. It is possible to manufacture a thermal head with high reliability, small size, and high yield without using γ film technology.

In addition, Figure 4 shows the green sheets ((A) to (A1) laminated in the lamination M step of the manufacturing process of the present invention in the lamination IIm, where 1 is an insulator green sheet, 2 is a conductor, and 3 is a lamination layer IIm). It shows a resistor layer formed by adhering raw resistor sheets. Also, raw sheets (A) (B) (/l → (71) are layers only of raw insulation sheets, and raw sheets 1-(C) 〜Mori) is an insulating raw sheet on which a resistor layer and a conductor layer are formed.The raw sheet 1-C→-・(The force is laminated by increasing or decreasing the number of laminated layers as necessary.

Note that Figure 4 shows the raw insulator sheet part per element to make the diagram easier to understand.
By printing a pattern in which the pattern shown in FIG. 4 is repeated many times on a plane, and laminating layers at once, it is possible to make a laminated ceramic thermal head of several tens to hundreds of pieces.

When a thermal head is made using lamination technology in this way, it is possible to make a large number of thermal heads by laminating layers several times, so the unit price per unit is significantly lower than that of conventional methods, and production costs are reduced. It is also possible to

Next, the present invention will be explained in detail by way of Examples &)1.

〔Example〕

An alumina-crystalline glass mixture was used as the insulator material. Powders of 50 wt% alumina and 5 Qwt% borosilicate lead crystallized glass were wet mixed in a ball mill, and then filtered and dried to obtain an insulating powder.

A ruthenium oxide insulator mixture was used as the resistor material. After weighing 3Qwt% of ruthenium oxide powder having a purity of 99.9% or more and 7owts of insulating powder, they were wet mixed, filtered and dried to obtain a resistor powder.

The insulator powder and the resistor powder were each dispersed in an organic vehicle to form a slurry, and the slurry was cast using a doctor blade to produce an insulator green sheet and a resistor green sheet having a film thickness of 20 μm to 500 μm. Note that polyvinyl butyral was used as the organic vehicle, and polyhydric alcohol ester was used as the solvent.

The outer shape of the raw insulator sheet was punched out using a mold, and a wiring pattern was printed thereon using a silver-palladium alloy paste by screen printing.

It was attached to a raw insulator sheet.

The resistor sheet made in this way is attached to a raw insulator sheet with conductors formed, a raw insulator sheet with only conductors formed, and, if necessary, a raw insulator sheet with only through holes formed. A predetermined number of them were placed in a mold, laminated, and thermocompression bonded.

The raw laminate that has been laminated is cut into a size of 5 x 10 pieces,
After removing the binder at 500°C, it was condensed at a temperature of 800°C to 1000°C.

Attaching an external IIv output electrode to the phosphorized laminate after firing,
After polishing the exposed surface of the resistor in contact with the thermal paper to a mirror finish, the lead wires were attached to the thermal head. ) Set the completed thermal head on the thermal printer.
-L,, When I conducted the i91 production test, [0 dot A□
~: 30 Totsudo / The N image of the battle is obtained and it is sufficiently practical,
Moreover, compared to conventional thermal heads, it was found that M: image quality was significantly improved.

As described above, the fR layer ceramic thermal head manufactured by the manufacturing method of the present invention has a resolution that cannot be achieved with conventional thermal heads, is compact and highly reliable, can be mass-produced, and can reduce costs. It turned out to be an excellent thermal head.

Although a ruthenium oxide based heating element was used as the resistance heating element in the present invention, similar results were obtained by using other resistive elements such as tantalum based, palladium based, nickel based, etc.

Furthermore, similar results were obtained using conductors such as gold, silver, platinum, copper, nickel, and alloys thereof.

[Brief explanation of the drawing]

Figure WS1 is a perspective view showing an example of a multilayer ceramic thermal head manufactured by the manufacturing method of the present invention.
The figure shows a cross-sectional view of the multilayer ceramic thermal head shown in FIG.
b) shows a cross section taken along the dashed-dotted line in FIG. FIG. 3 is a diagram showing the manufacturing process of the laminated ceramic thermal head of the present invention. FIG. 4 is a diagram showing the order of stacking raw sheets in the stacking step in the manufacturing method of the present invention. In each figure, 1 is a resistor, 2 is an insulator, 3 is an external electrode, and 4 is an internal conductor. Li 1 Figure 2 Figure 4

Claims (1)

[Claims] Steps of forming an insulator raw sheet and a resistor raw sheet; a step of forming a conductor layer on the insulator raw sheet; and a step of cutting the resistor raw sheet into a predetermined shape and forming the conductor layer on the insulator raw sheet surface. a step of gluing the insulator layer and a conductor layer to form a resistor layer; a step of laminating the insulator raw sheet with the resistor layer and conductor layer formed thereon, and a step of laminating the insulator green sheet to form a laminate; and a step of forming the laminate into a predetermined size. A multilayer ceramic thermal head characterized by comprising a step of cutting and sintering the sintered body, a step of polishing a predetermined part of the sintered body, and a step of polishing a predetermined part of the sintered body. Production method.