JPH0624210Y2 - Thermal head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a thermal head used in a thermal printer, and more particularly to a thin film type thermal head.

[Conventional technology]

The thermal head mounted on the thermal printer, for example, a plurality of heating resistor elements are linearly arranged on the same substrate, and the heating resistor elements are energized and heated according to the information, and color recording is performed on the thermosensitive recording paper. Alternatively, it is used for transfer recording on plain paper through an ink ribbon having an ink layer that melts by heat.

FIG. 2 shows an example of a general structure of a conventional thermal head of this type, in which a glaze made of glass that functions as a heat storage layer is formed on a heating resistor formation planned region of an insulating substrate 1 such as a ceramic substrate. The layer 2 is formed such that the cross section of the upper surface is arcuate. On this glaze layer 2 is T _a2
A plurality of heating resistor elements 3 made of N or the like are deposited in a layer shape by vapor deposition, sputtering or the like, and then etched, and a plurality of them are arranged linearly. On the heat generating resistor element 3, a power feeding body 4 for supplying power to the heat generating resistor element 3 is further formed. The power feeding body 4 is made of, for example, aluminum, copper, gold, or the like, and is deposited in a layer shape by vapor deposition, sputtering, or the like, and then formed into a pattern of a desired shape by etching, and is formed on both sides of each heating resistor element 3. One is led out as a common electrode 4A and the other is led out as an individual lead electrode 4B. Then, the common electrode 4A and the individual lead electrode 4
Each of the independent heating resistor elements 3 each having a heating area corresponding to one dot formed between the pair of power feeding elements 4 and 4 by applying a voltage between the pair of power feeding elements 4 and 4. It is designed to generate heat selectively. In FIG. 2, reference numeral 4a is a dividing portion of the power feeding body 4 formed by etching, and the heating resistor element 3 at the portion exposed by the dividing portion 4a constitutes the heating portion 3a. However, since the heat generating portion 3a is located at the apex of the glaze layer 2, the heat generating portion 3a has good contact with a thermal recording medium described later, and high quality can be obtained with relatively low power.

The protective layer 5 is formed on the heating resistor element 3 and the power feeder 4 described above. S _i O ₂ The protective layer 5 is to protect the heating resistor element 3 from oxidative degradation
And an oxidation resistant layer made of, for example, laminated on this oxidation resistant layer,
T _a2 O that protects the heating resistor element 3 and the power feeder 4 from abrasion due to contact with a thermal recording paper medium such as an ink ribbon
_{5 and the} like wear-resistant layer
Covers all of the head surface except the terminals. It should be noted that the protective layer 5 includes the dividing portion 4 of the power feeding body 4.
A band-shaped recess 5a corresponding to a is formed. The oxidation resistant layer and the wear resistant layer of the protective layer 5 are sequentially formed by means such as sputtering, and then, in the final step, the insulating substrate 1 is divided to obtain a desired thermal head chip.

According to the configuration described above, the thermal head is pressed against the recording paper 8 wound around the platen 7 of the printer via the ink ribbon 6, and the heating resistor of the thermal head is run while the thermal head is running in the arrow direction. By selectively and instantaneously generating heat in the element 3, the protective layer 5 in the portion facing the heat generating resistor element 3 that has generated heat is heated, and the heat of the protective layer 5 is applied to the ink ribbon 6 adjacent to this portion. The ink of the ink ribbon 6 is partially melted by being transferred to the recording medium 8 and the melted ink is cooled and solidified and transferred to the recording paper 8 to perform thermal recording.

[Problems to be solved by the invention]

By the way, in the above-mentioned printer, while the relative position between the thermal head and the ink ribbon 6 is changed, the ink of the ink ribbon 6 is repeatedly melted and cooled and solidified to transfer the ink to the recording paper 8. In addition, since the upper surface of the glaze layer 2 has an arcuate cross section, the pressure contact force of the thermal head with respect to a predetermined portion of the ink ribbon 6 disappears instantaneously. It will be peeled off momentarily.

In the case of such a printer, if the printing speed, that is, the running speed of the thermal head is increased, the ink ribbon 6 of the thermal head is melted by the heat generation of the heating resistor element 3 of the thermal head before the ink of the thermal head is cooled and solidified. There is a possibility that the pressure contact force against the ink disappears and the ink ribbon 6 is peeled off from the recording paper 8, the ink running out of the ink ribbon 6 deteriorates, and the print quality during high-speed printing cannot be maintained good.

An object of the present invention is to provide a thermal head that overcomes the problems of the conventional example and can maintain good print quality even when high-speed printing is performed by the printer.

[Means for solving problems]

According to the present invention, a Grace layer having an arcuate cross section is formed on an insulating substrate, a plurality of heating resistor elements are arranged on the Grace layer, and power is supplied to each heating resistor element. In a thermal head formed by connecting a power feeding element to a heating resistor element, a plurality of strip-shaped protrusions are provided on the Grace layer at intervals in the circumferential direction of the Grace layer, and among these strip-shaped protrusions. It is characterized in that the heat generating portion of the heat generating resistor element is arranged on the strip-shaped protrusion on the front end side in the printing direction.

[Action]

According to the present invention, another strip-shaped protrusion located on the rear end side in the printing direction of the strip-shaped protrusion on which the heat-generating portion of the heat-generating resistor element is disposed can be used for thermal recording on a thermal recording medium such as an ink ribbon for a long time. Since the pressure contact force of the head is maintained until the ink is cooled and solidified, the ink will not run out even when high-speed printing is performed, and good print quality can be maintained.

〔Example〕

Hereinafter, the present invention will be described with reference to the embodiments shown in the drawings. It should be noted that the same components as those of the conventional one described above are denoted by the same reference numerals in the drawings, and the description thereof will be omitted.

FIG. 1 shows an embodiment of a thermal head according to the present invention, in which a glaze layer 2 having an arcuate cross section on its upper surface formed on an insulating substrate 1 has a small gap on both sides of its top 2a. A plurality of (two in the present embodiment) strip-shaped projections 2b and 2c are integrally provided so as to extend in the direction in which the heating resistor elements 3 are continuously provided. Each band-shaped protrusion 2b, 2c
Is a pair of inclined side surfaces 2d, 2d and both side surfaces 2d, 2d.
an upper surface 2e having an arcuate cross section connected to both ends of d, and the insulating substrate 1 exposed to the surface of the glaze layer 2 including these strip-shaped projections 2b and 2c and to the outside.
A plurality of heat-generating resistor elements 3 are formed on the upper side in an array. The common electrode 4A of the power feeding body 4 is formed on the heating resistor element 3 between the two strip-shaped protrusions 2b and 2c in the vicinity of the top portion 2a of the glaze layer 2, and also in the printing direction indicated by the arrow. An individual lead electrode 4B of the power feeding body 4 is formed on the heating resistor element 3 on the side of the strip-shaped protrusion 2b located on the tip side. Therefore, each heating resistor element 3 on the strip-shaped protrusion 2b constitutes the heating portion 3a.
A protective layer 5 similar to that shown in FIG. 2 is formed on the heating resistor element 3 and the power feeding body 4, and the strip-shaped protrusion of the glaze layer 2 is formed on the protective layer 5. Band-shaped protrusions 5b and 5c corresponding to the portions 2b and 2c are formed. Further, the manufacturing method of the heating resistor element 3, the power feeding body 4 and the like is the same as the conventional method, and therefore the description thereof is omitted.

Next, the operation of the above-described embodiment will be described.

The platen 7 of the printer is a roll type or a square type coated with rubber. A thermal head is pressed against the recording paper 8 wound around the platen 7 via the ink ribbon 6, and the thermal head is pressed. Running in the direction of the arrow for high-speed printing, the thermal head travels and the thermal head changes its relative position to the ink ribbon 6. However, the thermal head is formed on the strip-shaped protrusion 2b of the glaze layer 2. The ink ribbon 6 in which the ink in the opposing portion is melted through the protective layer 5 due to the heat generation of the heat generating portion 3a of the heat generating resistor element 3 comes to a position where it is sandwiched between the strip-shaped protrusion 5c of the protective layer 5 and the recording paper 8. Since the pressure contact force from the thermal head is continuously received, the duration of the pressure contact force of the thermal head with respect to the ink ribbon 6 can be extended, and The penetration for the recording paper 8 of the melted ink in the down 6 with enhanced by this pressing force, it is possible to sustain the pressing force until the ink is cooled and solidified. As a result, the ink on the ink ribbon 6 becomes good, and the print quality on the recording paper 8 during high-speed printing can be kept good.

The duration of the pressure contact force of the thermal head with respect to the ink ribbon 6 described above depends on the number of strip-shaped protrusions of the glaze layer 2 and the width in the printing direction in consideration of the printing speed, the ink material of the ink ribbon 6, and the like. It can be adjusted and set variously.

According to the present embodiment, since the plurality of strip-shaped projections 2b and 2c provided on the glaze layer 2 can maintain the pressure contact force of the thermal head with respect to the portion of the ink ribbon 6 where the ink is melted, high-speed printing is performed. It is possible to maintain a good print quality.

The present invention is not limited to the above-described embodiments, but various modifications can be made.

[Effect of device]

According to the present invention, since the duration of pressure contact with a thermal recording medium such as an ink ribbon can be lengthened, it is possible to maintain good print quality by keeping ink out, and especially for high-speed printing. Has the excellent effect of being suitable.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of an essential part showing an embodiment of a thermal head according to the present invention, and FIG. 2 is a longitudinal sectional view of the essential part showing a conventional thermal head. 1 ... Insulating substrate, 2 ... Glaze layer, 2b, 2c ... Strip protrusions, 3 ... Heating resistor element, 4 ... Feeder, 5 ...
Protective layer, 6 ... Ink ribbon, 7 ... Platen, 8 ...
Recording paper.

Claims (3)

[Scope of utility model registration request] 1. A Grace layer having an arcuate cross section formed on an insulating substrate, and a plurality of heating resistor elements are disposed on the Grace layer to supply electric power to each heating resistor element. In a thermal head formed by connecting the power feeding body of 1 to a heating resistor element, a plurality of strip-shaped projections are provided on the grace layer at intervals in the circumferential direction of the grace layer. A thermal head characterized in that the heat generating portion of the heat generating resistor element is disposed on a strip-shaped protrusion on the front end side in the printing direction. 2. The thermal head according to claim 1, wherein the two band-shaped protrusions are formed, and one power feeding member is arranged between the band-shaped protrusions. 3. The thermal head according to claim 2, wherein the power supply member between the two strip-shaped protrusions is arranged at a central position in the circumferential direction of the grace layer.