JPH0661950B2 - Thermal head - Google Patents

Description

TECHNICAL FIELD The present invention relates to a thermal head suitable for use in a thermal printer.

[Prior Art] FIG. 3 is a sectional view showing a conventional thermal head. In this figure, 1 is a substrate made of aluminum oxide,
A glass glaze layer 2 is laminated on the upper surface of the substrate 1. A heating resistor 3 is formed on the upper surface of the glass grace layer 2, and electrodes 4a and 4b are formed on the upper surface of the resistor 3 with a predetermined distance. The heating resistor 3 exposed between the electrodes 4a and 4b serves as a heating portion 3a. The electrode
One of 4a and 4b is grounded, and the other is connected to the output end of a power supply controller (not shown) (having a function of supplying a current to the heat generator 3a). Reference numeral 5 denotes an oxidation resistant film, which is formed so as to cover the electrodes 4a and 4b. A friction resistant film 6 is formed on the upper surface of the oxidation resistant film 5. The oxidation resistant film 5 and the wear resistant film 6 form a protective film.

Here, FIG. 4 is a plan view showing details of the above-mentioned thermal head, and as shown in this figure, the heat generating portion 3a has a rectangular shape.

In the thermal head having such a configuration, when a current flows through the heat generating portion 3a, the entire surface of the heat generating portion 3a uniformly generates heat. As a result, the transfer paper not shown has a fourth
Dot printing of the shape shown by the broken line D in the figure is performed.

[Problems to be Solved by the Invention] In order to express the density gradation of an image in a thermal printer, it is desirable to control the size of dots to be printed. In that case, dot printing can be performed only in a shape based on the shape of the heat generating portion 3a.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a thermal head capable of controlling the size of dots to be printed.

[Means for Solving the Problems] In order to solve the above problems, according to the present invention, there is provided a thermal head in which an insulating layer, a heating portion, and a protective layer are sequentially laminated on one surface of a substrate. A rectangular heat transfer material provided at a position corresponding to the heat generating portion, and a rectangular heat transfer material provided at a position corresponding to the heat generating portion and around the rectangular heat transfer material so as to face each other and A heat transfer member composed of a plurality of planar U-shaped heat transfer materials each having a larger area is disposed, and the heat transfer member is close to the heat generating portion according to the amount of heat generated from the heat generating portion. It is characterized in that heating is performed in order from the heat transfer material.

[Operation] According to the above configuration, since the heat transfer material closer to the heat generating portion is sequentially heated according to the amount of heat generated from the heat generating portion, it is possible to control the energizing time of the current flowing through the heat generating portion or its amplitude. The heating range of the heat transfer member can be set. Therefore, the size of the printed dots can be controlled.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

1 is a plan view showing an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG. In these figures, the portions corresponding to those in FIG. 3 described above are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 1, reference numeral 7 is a heating resistor, and electrodes 4a and 4b are formed on the upper surface of the heating resistor 7 at a predetermined distance. The portion of the heating resistor 7 exposed between the electrodes 4a and 4b serves as the heating portion 7a. Further, the heat generating portion 7a is
The length in the width direction is formed shorter than the length in the width direction of the heating resistor 7. Reference symbols C ₁ , C _2a , C _3a ,
C _4a , C _2b , C _3b and C _4b are heat transfer materials made of aluminum. The heat transfer material C ₁ is formed in a square shape whose length in the width direction corresponds to the length in the width direction of the heat generating portion 7 a, and is arranged so as to be located in the central portion of the heat generating portion 7 a. The heat transfer material _{C 2a, C 2b} are formed in each plane "U" shape, a predetermined distance apart in the heat transfer material _{C 1} from the heat transfer material _{C 1}
Are arranged so as to be sandwiched from the left and right directions in the drawing. The heat transfer material _{C 3a, C 3b} is formed in each flat "U" shape, disposed heat transfer material _C 2 _a, these heat transfer material _C 2a by a predetermined distance from the _{C 2b,} a _{C 2b} so as to sandwich the horizontal direction in the drawing Has been done. The heat transfer material _{C 4a, C 4b} are formed in each plane "U" shape, is disposed so as to sandwich these heat transfer material _{C 3a,} a _{C 3b} from horizontal direction in the drawing the heat transfer material _{C 3a,} from _{C 3b} by a predetermined distance ing. These heat transfer materials C ₁ , C _{2a to} C _4a ,
C _{2b to} C _4b are all formed on the upper surface of the oxidation resistant film 5 with the same thickness as shown in the sectional view of FIG. 2. Further, these heat transfer materials C ₁ , C _{2a to} C _4a , C _{2b to} C
_4b constitutes a heat transfer member.

Subsequently, in FIG. 2, 6a is heat transfer material _{C 1, C 2a} ~
The wear resistant film is formed so as to cover C _4a and C _{2b to} C _4b , and the heat transfer material C ₁ , C ₁ is formed on the upper surface of the wear resistant film 6a.
V-shaped notches 8 having a valley bottom on the center line between each of C _{2a to} C _4a and C _{2b to} C _4b are formed. The oxidation resistant film 5 and the wear resistant film 6a form a protective film.

In the thermal head formed in this way, when a current flows through the heat generating portion 7a, the entire surface of the heat generating portion 7a uniformly generates heat. Then, in accordance with the amount of generated heat, the range transmitted to each of the heat transfer materials C ₁ , C _{2a to} C _4a , C _{2b to} C _4b is determined. In this case, Kakuden'netsuzai _{C 1, C 2a} ~
C _4a and C _{2b to} C _4b respectively have an area and a heat generating portion 7.
Depending on the distance from “a”, the inner one becomes hotter in a shorter time. Therefore, the heat transfer materials C ₁ → C _2a , C _2b → C _3a , C _3b → C _4a , C are increased as the duration of the current flowing through the heat generating portion 7a is increased or the amplitude of the current is increased.
_4b in this order, and when applied to a thermal transfer printer, for example, the ink applied to the transfer film is in the order in which the heat transfer materials C ₁ , C _{2a to} C _4a , and C _{2b to} C _{4b also} become high in temperature. The range of dissolution will expand. Since the melted ink is transferred to the transfer paper, the dots to be transferred are gradually increased.

In this way, the size of the dots to be printed can be controlled by changing the energization time or the amplitude of the current passed through the heat generating portion 7a. Therefore, it is possible to express the density gradation by changing the dot size.

Even when applied to a thermal-type thermal printer (a printer that uses thermal paper that develops color when heat is applied), dots that cause the thermal paper to develop color by changing the energization time or the amplitude of the current that flows in the heat-generating section in the same manner. The size of can be controlled.

In the above embodiment the heat transfer material _C 2a _{~C 4a, C 2b} ~
C _4b was formed in a planar "U" shape, but C _2a and C
_2b , C _3a and C _3b , C _4b may be integrally formed into an annular shape.

Further, although the heat transfer materials C ₁ , C _{2a to} C _4a , and C _{2b to} C _4b are each formed of aluminum, any other material having good thermal conductivity such as copper or silver may be used.

Further, heat transfer material _{C 1, C 2a ~C 4a,} was placed on top of the C 2b _{-C 4b} each oxidation film 5, these heat transfer materials _{C 1, C 2a ~C 4a,} C 2b ~C 4b Need not be in contact with the heat generating portion 7a, and may be disposed on the upper surface of the abrasion resistant film 6a, for example.

As described above, according to the present invention, in the thermal head in which the insulating layer, the heat generating portion, and the protective layer are sequentially stacked on one surface of the substrate, the thermal head corresponds to the heat generating portion. A rectangular heat transfer material provided at a position and a position corresponding to the heat generating portion and provided so as to sandwich the rectangular heat transfer material at and around the position. A heat transfer member including a plurality of planar U-shaped heat transfer members is disposed, and the heat transfer member is heated in order from the heat transfer member close to the heat generating unit according to the amount of heat generated from the heat generating unit. Therefore, the size of the dots to be printed can be controlled by controlling the current application time of the current flowing to the heat generating portion or its amplitude.

[Brief description of drawings]

1 is a plan view showing an embodiment of the present invention, FIG. 2 is a sectional view taken along the line AA of FIG. 1, FIG. 3 is a sectional view showing a conventional thermal head, and FIG. 4 is a detail of the thermal head. FIG. 1 ... Substrate, 2 ... Glass grace layer (insulating layer), 7a
...... heating _{unit, C 1, C 2a ~C 4a} , C 2b ~C 4b ...
… Heat transfer material (constituting heat transfer member), 5 ... Oxidation resistant film, 6
a ... Abrasion resistant film (5 and 6a form a protective film).

Claims (2)

[Claims] 1. An insulating layer, a heat generating part, and a heat generating part on one surface of a substrate.
In a thermal head in which a protective layer is sequentially laminated, a rectangular heat transfer material is provided at a position corresponding to the heat generating portion, and the rectangular heat transfer material is sandwiched at and around a position corresponding to the heat generating portion. A heat transfer member that is provided with a plurality of planar U-shaped heat transfer members facing each other and having a larger area toward the outer side, the heat transfer member being generated from the heat generating portion. A thermal head characterized in that heating is performed in order from a heat transfer material near the heat generating portion according to the amount of heat generated. 2. The thermal head according to claim 1, wherein the heat transfer member is formed of a metal having a good thermal conductivity.