JPH05318799A - Thermal head - Google Patents

Abstract

PURPOSE:To provide a thermal head sliding without damaging thermal paper or a thermal transfer ribbon and performing printing of high quality on recording paper. CONSTITUTION:A thermal head is constituted by forming a plurality of heating resistors on a square insulating substrate 2 along one side among two sides meeting each other at a right angle on the upper surface of the substrate 2 by membrane forming technique and providing a plurality of the connection terminals 6 connected to an external electric circuit on the substrate 2 along the other side and electrically connecting the heating resistors 3 and the connection terminals 6 by a conductive layer 4 formed by membrane forming technique. The connection terminals 6 are formed at a position lower than the surface provided with the heating resistors 3 by thick membrane forming technique.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a thermal head incorporated in a printer mechanism such as a word processor, and more particularly, an improvement of a serial type thermal head for printing and printing while slidingly contacting a recording paper at a predetermined speed. It is about.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, a serial type thermal head incorporated in a printer mechanism such as a word processor is made of an electrically insulating material such as alumina ceramics. A plurality of heat generating resistors 12 and the like, and the heat generating resistors
The heating resistor 12 has a structure in which a plurality of conductive layers 13 for supplying electric power to cause Joule heat generation are attached to each heating resistor 12, and each heating resistor 12 has a conductive layer 13 Power is applied to the heating resistor 12 to generate Joule heat, and the heating resistor 12 is slidably contacted with the thermal paper or the thermal transfer ribbon.
Predetermined printing and printing are performed on the recording paper by discoloring the thermal paper with the heat generated by 12 or transferring the ink of the thermal transfer ribbon to the recording paper.

In the thermal head, the heating resistors 12 are linearly arranged along one side of the insulating substrate 11 (the side on the rear side in the sliding contact direction with the thermal paper). When printing on recording paper by sliding the body 12 to thermal paper or thermal transfer ribbon, it makes the thermal head slide well on thermal paper or thermal transfer ribbon, and effectively prevents bleeding of printing or printing. ing.

Further, since the heating resistor 12 and the conductive layer 13 deposited on the insulating substrate 11 are fine patterns, it is usual to adopt a thin film forming technique such as a sputtering method or an ion plating method and a photolithography technique. Is formed by.

Further, a conductive layer connected to the heating resistor 12
The end of 13 is led out to one side of the insulating substrate 11 in the direction orthogonal to the arrangement direction of the heating resistors 12, the end constitutes a connection terminal 14 connected to an external electric circuit, and the external electric circuit board 15 The wiring 16 is attached and connected via solder or the like.

However, in this conventional thermal head, the heating resistor 12 and the conductive layer 13 for supplying electric power to the heating resistor 12 are formed on the same plane and are formed at the end of each conductive layer 13. Since the connection terminal 14 and the wiring 16 of the external electric circuit board 15 are connected via solder or the like, the wiring 16 of the external electric circuit board 15 and the connection terminal 14 are
The height of the connection portion with and becomes higher than the height of the heating resistor 12, as a result, when the thermal head is brought into sliding contact with thermal paper or thermal transfer ribbon, and when printing or printing on recording paper, the external electric circuit board is used. The connection portion between the wiring 16 of 15 and the connection terminal 14 contacts the thermal paper or the thermal transfer ribbon to scratch the thermal paper, or the contact between the thermal paper or the thermal transfer ribbon and the heating resistor becomes incomplete. It has a drawback that high quality printing and printing cannot be formed on the recording paper.

Therefore, in order to solve the above-mentioned drawbacks, an insulating substrate
The position of the connection terminal 14 provided on 11 is made lower than the surface on which the heating resistor 12 is adhered by providing a step on the insulating substrate 11, and thereby the wiring 16 of the external electric circuit board 15 and the connection terminal 14 are separated. It is possible to keep the height of the connection portion low.

However, when a step is formed on the insulating base 11, a conductive layer having a connection terminal 14 at the end is formed on the upper surface of the insulating base 11.
When depositing 13 by thin film formation technology such as sputtering and patterning by photolithography technology, it becomes impossible to form a uniform thickness at the stepped portion and patterning disturbance due to interference of exposure light occurs. As a result, the desired accurate pattern cannot be obtained, and as a result, the conductive layer 13 is broken, or the adjacent conductive layer 13 is short-circuited, which causes a defect that the function as a thermal head is lost. ..

[0009]

[Purpose] The present invention has been devised in view of the above-mentioned drawbacks, and an object thereof is to perform sliding and printing on a recording paper with high quality without damaging the thermal paper or thermal transfer ribbon. It is to provide a thermal head.

[0010]

The present invention provides a plurality of heating resistors formed by a thin film forming technique along one of two sides orthogonal to each other on the upper surface of a rectangular insulating substrate, and A thermal head in which a plurality of connection terminals connected to an external electric circuit are attached along the sides, and the heating resistor and the connection terminals are electrically connected by a conductive layer formed by a thin film forming technique. The connection terminal is formed by a thick film forming technique at a position lower than the surface on which the heating resistor is adhered.

[0011]

According to the thermal head of the present invention, since the connection terminal connected to the external electric circuit is formed at a position lower than the surface on which the heating resistor is formed, the wiring of the external electric circuit board is soldered to the connection terminal. The height of the connecting portion is lower than that of the heat-generating resistor even when connected via, and as a result, the connecting portion of the wiring of the external electric circuit board and the connecting terminal comes into contact with the thermal paper or the thermal transfer ribbon and becomes a thermal paper. It is possible to form high quality prints and prints on the recording paper without causing scratches and at the same time making good contact between the heat sensitive paper or the heat transfer ribbon and the heat generating resistor.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings. Figure 1 is a plan view of the thermal head according to the present invention.
2 is a sectional view of the thermal head shown in FIG.
Shows a side view of the thermal head shown in FIG. 1, and the thermal head 1 is basically composed of an insulating substrate 2, a heating resistor 3 and a conductive layer 4.

The insulating substrate 2 is made of an electrically insulating material such as alumina ceramics, and the heating resistor 3 and the conductive layer 4 are adhered on the upper surface of the insulating substrate 2. When the heating resistor 3 and the conductive layer 4 are supported, the insulating substrate 2 functions as a supporting member. To do.

The insulating substrate 2 made of an electrically insulating material such as alumina ceramics is, for example, alumina (Al ₂ O ₃ )
, Silica (SiO ₂ ), magnesia (MgO), calcia (CaO)
Ceramic green sheet (ceramic green sheet) is formed by adding a suitable organic solvent and solvent to raw material powder such as to form a slurry and forming it into a sheet by using the well-known doctor blade method or calender roll method. Sheet), and then the ceramic green sheet is punched into a predetermined shape by a punching process,
It is made into a square shape by firing at (about 1600 ° C).

Further, a band-shaped heat storage layer 5 is deposited on the upper surface of the quadrangular insulating substrate 2 along one side thereof (the side on the rear side in the sliding contact direction in the sliding contact with the thermal paper or the thermal transfer ribbon). The heat storage layer 5 appropriately accumulates the heat generated by the heating resistor 3 and acts so that the thermal head quickly reaches the high temperature required for printing.

The heat storage layer 5 is made of, for example, SiO ₂ --BaO--Ca.
O over Al ₂ O ₃ over B ₂ O ₃ type glass, SiO _2, over Al ₂ O ₃
-Made of glass such as BaO-based glass, a glass paste obtained by adding and mixing an appropriate organic solvent and solvent to glass powder of the specified components is applied by printing on the upper surface of the insulating substrate 2 in a strip shape by a conventionally known screen printing method. By baking this at a temperature of about 700 ° C., it is applied in a strip shape on the upper surface of the insulating substrate 2.

A band-shaped heat storage layer 5 adhered to the insulating substrate 2
A plurality of heating resistors 3 are linearly arranged and deposited on the upper side of the heating resistor 3. At both ends of the heating resistor 3, the individual conductive layers 4a individually connected to the heating resistors 3 and the heating resistors are attached. A conductive layer 4 consisting of a common conductive layer 4b commonly connected to the body 3 is applied.

The heating resistor 3 is made of tantalum nitride or the like, and since the heating resistor 3 itself has a predetermined electric resistivity, it is individually attached to both ends of the heating resistor 3. When electric power is supplied and applied through the conductive layer 4a and the common conductive layer 4b, Joule heat is generated, and heat is generated at a temperature required to form a printed image, for example, a temperature of 300 to 450 ° C.

The heating resistor 3 is applied in a fine pattern on the heat storage layer 5 applied to the upper surface of the insulating substrate 2 by using a thin film forming technique such as a sputtering method and a photolithography technique which are well known in the art. It is formed.

A conductive layer 4 composed of an individual conductive layer 4a and a common conductive layer 4b is adhered and connected to both ends of the heating resistor 3, and the conductive layer 4 causes Joule heating to the heating resistor 3. It has a function of supplying a predetermined electric power for causing the operation.

The conductive layer 4 is made of aluminum (Al), copper (Cu)
Made of a metal such as
A fine pattern is adhered to and formed on one side of the heating resistor 3 in a direction orthogonal to the arrangement direction.

Further, the conductive layer 4 is connected to a connecting terminal 6 provided on one side of the insulating substrate 2 at a portion led out to one side of the insulating substrate 2, and the connecting terminal 6 has an external electric circuit board 7 connected thereto.
The wiring 8 is attached and connected through a brazing material such as solder.

The connection terminal 6 to which the conductive layer 4 is connected functions to connect the wiring 8 of the external electric circuit board 7 and the conductive layer 4, and as shown in FIG. It is formed in the region A.

The connection terminal 6 is a stepped area A of the insulating substrate 2.
Since it is formed at a position lower than the heating resistor 3, the connection terminal 6 is connected to the wiring 8 of the external electric circuit board 7.
Even if they are attached and connected via a brazing material such as solder, the height of the connection portion is considerably lower than the position of the heating resistor 3, and as a result, at the time of printing, the wiring 8 of the external electric circuit board 7 and the connection terminal 6 are connected.
Since the connection part with does not contact the thermal paper or thermal transfer ribbon, it does not scratch the thermal paper, etc., and at the same time, the thermal paper and thermal transfer ribbon are in good contact with the heating resistor to ensure high quality recording paper. Can be printed and printed.

The connection terminal 6 is made of a metal such as gold or silver, and a metal paste obtained by adding and mixing an appropriate organic solvent or solvent to the metal powder is applied to the step area A of the insulating substrate 2 by a conventionally known screen. By applying a printing method or the like and printing it at a temperature of about 600 ° C., the stepped region A of the insulating substrate 2 is partially formed in contact with the conductive layer 4 to form a predetermined pattern. It In this case, since the connection terminal 6 is formed by a thick film forming technique such as screen printing, even if the insulating substrate 2 has a step, it can be accurately formed in a predetermined thickness and a predetermined pattern. The conductive layer 4 can be securely connected to the wiring 8 of the external electric circuit board 7 via the connection terminal 6, and the heating resistor 3 can be connected from the wiring 8 of the external electric circuit board 7 to the conductive layer 4.
It is possible to reliably supply the predetermined electric power required to generate Joule heat.

An insulating substrate on which the connection terminal 6 is formed
The stepped region A of 2 is formed on one side of the insulating base 2 by mechanically processing one side of the insulating base 2 using a grinding plate or by scraping off a part of the ceramic green sheet to be the insulating base 2 with a cutter knife or the like. To be done.

Thus, according to the thermal head of the present invention, electric power is applied to each heating resistor 3 via the wiring 8 of the external electric circuit board 7 and the conductive layer 4 to heat the heating resistor 3 by Joule heat and the thermal paper. And sliding contact with the thermal transfer ribbon,
Predetermined printing and printing are performed on the recording paper by discoloring the thermal paper with the heat generated by the heating resistor 3 or transferring the ink of the thermal transfer ribbon to the recording paper.

The present invention is not limited to the above-mentioned embodiments, but various modifications can be made without departing from the scope of the present invention. For example, the heating resistor 3 and the conductive layer.
If the surface of 4 is covered with a protective film 9 made of silicon nitride, sialon, etc., it is effective for the heating layer 3 and conductive layer 4 to be worn by sliding contact with the thermal paper or thermal transfer ribbon by the coating layer 9. Can be prevented and heat generating resistor
It is possible to prevent the moisture contained in the atmosphere and the sodium ions contained in the thermal paper from coming into contact with 3 and the conductive layer 4 and effectively prevent the heating resistor 3 and the conductive layer 4 from being oxidized and corroded. ..

[0029]

According to the thermal head of the present invention, since the connection terminal to which the wiring of the external electric circuit board is connected is formed at a position lower than the surface on which the heating resistor is formed, the external electric circuit board is connected to the connection terminal. Even if the wiring is connected via solder or the like, the height of the connecting portion is lower than that of the heating resistor, and as a result, the connecting portion between the wiring of the external electric circuit board and the connecting terminal contacts the thermal paper or thermal transfer ribbon. Thus, the thermal paper or the like is not damaged, and at the same time, the thermal paper or the thermal transfer ribbon can be brought into good contact with the heating resistor to form high-quality prints and prints on the recording paper.

Further, since the connection terminals are formed by a thick film forming technique such as screen printing, the connection terminals and the conductive layer can be surely connected to each other and a short circuit between adjacent connection terminals is completely eliminated. As a result, the electric power supplied from the wiring of the external electric circuit board can be surely applied to each heating resistor through the conductive layer, and each heating resistor can accurately generate the predetermined Joule heat required for printing. Can be done.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a thermal head of the present invention.

FIG. 2 is a sectional view taken along line XX of the thermal head shown in FIG.

FIG. 3 is a side view of the thermal head shown in FIG.

FIG. 4 is a plan view of a conventional thermal head.

[Explanation of symbols]

 1-Thermal head 2--Insulating substrate 3--Heating resistor 4--Conductive layer 5--Heat storage layer 6-Connecting terminal 7・ ・ ・ ・ ・ External electric circuit board 8 ・ ・ ・ ・ ・ Wiring

Claims (1)

[Claims] 1. A plurality of heating resistors formed by a thin film forming technique along one side of two sides orthogonal to each other on the upper surface of a rectangular insulating substrate, and an external electric circuit along the other side. A thermal head having a plurality of connection terminals attached to each other, and electrically connecting the heating resistor and the connection terminals by a conductive layer formed by a thin film forming technique. Is a thermal head characterized by being formed by a thick film forming technique at a position lower than the surface on which the heating resistor is applied.