JPH0631964A - Thermal head - Google Patents

Abstract

PURPOSE:To make it possible to record uniformly on the whole face in a record medium by providing a plurality of heat generating resistors arranged together with a glass-glazed layer and a feeder on a substrate, increasing/decreasing sheet resistance value of the heat generating resistors, and properly varying individual resistance values of the heat generating resistors. CONSTITUTION:A base having a glass-glazed layer 2 formed on a substrate 1 of ceramic, a plurality of heat generating resistors 3 arranged on the glass- glazed layer 2, and a feeder for supplying electric power to the heat generating resistors 3 are provided. Structure of film is changed such that the resistance values of the heat generating resistors 3 vary properly in a thermal head. The heat generating resistors 3 which are serial and adjacent to each other are treated as blocks. Besides, the heat generating resistors 3 which contribute to printing are divided into two or more blocks from connecting, structural, and handling points of view. However, since resistance value of each dot varies at random properly, the boundary between blocks will be hidden in the variation at distribution of resistance value, so that the boundary between the blocks will not appear clearly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head used in a thermal type or thermal transfer type printer.

[0002]

2. Description of the Related Art FIG. 1 is a sectional view of a main part of a conventional thermal head, and FIG. 6 is a sectional view taken along the line AA 'in FIG. In the figure, 1 is a substrate such as a ceramic material, 2 is a glass glaze layer, 3 is a heating resistor, and 4 is a heating resistor.
Is a power supply for supplying electric power to the heating resistor.

Conventionally, generally in a thermal head,
The heat generating resistor 3 has a cross-sectional structure as shown in FIG. 6, and all the heat generated in the thermal head is generated whether the thin film process such as sputtering is used or the thick film process such as printing is used. The resistor 3 was formed uniformly in terms of material and shape. Then, electric power is supplied from the power supply body 4 to the heating resistor 3 to generate heat, and the heat energy is used to perform recording.

[0004]

In the conventional thermal head having such components, a plurality of adjoining and continuous heating resistors 3 are handled as one unit, that is, a block, and Of the resistance value distribution in the thermal head when at least all the heating resistors 3 that contribute to printing are divided into at least two or more blocks from the viewpoints of wiring of the electric circuit, structure, handling, etc. A rough appearance is shown in FIG.

Further, in the state of the resistance value distribution of the conventional thermal head of FIG. 7, the portion corresponding to the boundary between the blocks shown in FIG. 6 is the portion indicated by B in FIG. As shown in FIG. 7, in the conventional thermal head, the resistance value increases from the center of the thermal head toward the outside, and the thermal head is divided into at least two blocks. However, it is inevitable that the state of the change of the resistance value changes in a staircase and rises, and a large step is generated in the state of the distribution of the resistance value on both sides of the boundary between the blocks.

As a result, in the case of the conventional thermal head, at the time of actual printing, the difference in the printing of the boundary between the blocks occurs enough to be perceived by human eyes,
As the presence of blocks is confirmed, the state of printing is clearly different between blocks, and thus there is a drawback that uniform printing cannot be realized on the entire surface of the recording medium.

An object of the present invention is to provide a thermal head which solves the above problems in the conventional thermal head and can realize uniform printing over the entire surface of the recording medium during actual printing. is there.

[0008]

In order to solve the above problems, in the thermal head of the present invention, conventionally, all the heating resistors 3 in the thermal head are formed uniformly in material and shape, and the sheet resistance distribution is also In contrast to being uniform in the thermal head, each of the plurality of heating resistors 3 belonging to the thermal head is formed of various multilayer films made up of one or more layers, and By changing the film configuration and increasing or decreasing the sheet resistance value of each heating resistor 3, the respective resistance values of the heating resistors 3 in the thermal head are randomly varied as appropriate and are adjacent to each other during printing. The thermal head does not have a clear boundary between blocks.

[0009]

In the thermal head configured as described above, each of the plurality of heat generating resistors 3 belonging to the thermal head is formed of various multilayer films of one or more layers,
By changing the film structure of each heating resistor 3 itself and increasing or decreasing the sheet resistance value of each heating resistor 3, the resistance value of each heating resistor 3 in the thermal head is randomly changed. Dispersion, the resistance value distribution of the thermal head does not generate a clear boundary between adjacent blocks, and is divided into at least two blocks from the viewpoint of electrical circuit connection, structure, handling, etc. Also in the case of actual printing, it is possible to perform printing evenly enough so that the difference in printing state between blocks printed on the printing medium is not perceptible to human vision. Realized thermal head.

[0010]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a main portion of a general thermal head, and FIG. 2 is a sectional view of a portion corresponding to AA ′ in FIG. 1, showing an embodiment of the present invention.

In FIG. 2, reference numeral 1 is a substrate made of a ceramic material or the like, 2 is a glass glaze layer, 3 is a heating resistor, and 4 is a feeder for supplying electric power to the heating resistor 3. In the present embodiment, as shown in FIG. 2, the film configuration is changed so that the resistance values of the heating resistors 3 in the thermal head vary randomly at appropriate times. FIG. 3 shows the distribution of resistance values of the thermal head according to this embodiment.

Conventionally, the resistance value distribution in the thermal head is
A plurality of adjacent and continuous heat generating resistors 3 are treated as one unit, that is, a block, and at least all the heat generating resistors 3 that contribute to printing are connected on an electric circuit, structurally, It is divided into at least two blocks from the viewpoint of handling. In the thermal head in this case, as shown in FIG. 7, when the resistance value increases from the center to the outside of the thermal head and the thermal head is divided into at least two or more blocks. , The state of the change in the resistance value changes stepwise and rises.

On the other hand, in FIG. 3 in the case of the resistance value distribution of the thermal head of the present invention, since the resistance values of the respective dots are randomly varied as appropriate, the boundaries between the blocks in the resistance value distribution may vary. Since they are hidden, the boundaries between blocks do not appear clearly.

As a result, due to the connection of the electric circuit, the structure,
Even when divided into at least two blocks from the viewpoint of handling, the difference in the printing state between the blocks recorded on the recording medium during actual printing is A thermal head has been realized which is capable of recording evenly enough to be imperceptible.

The thickness distribution of the heating resistor 3 used in this embodiment can be easily formed by the following method. As shown in FIG. 8, first, after film formation as shown in (a) and (a), pattern formation is performed, and then film formation and patterning are performed again as shown in (c) and (d), and further (e). ,
It is possible to form a desired thickness distribution by performing film formation and patterning again as in (f).

Furthermore, the above (a) and (a) film forming-patterning films and the following (c), (d), (e),
In order to eliminate the interface between the film formation and patterning of (f), appropriate heat treatment (annealing) may be applied at the stage of (e) or (f) for durability after completion of the thermal head. It is useful for improving the reliability and reliability.

(Embodiment 2) FIG. 4 shows AA 'in FIG.
It is sectional drawing of an equivalent part. In FIG. 4, 1 is a substrate such as a ceramic material, 2 is a glass glaze layer, 3 is a heating resistor, and 4 is a power feeding body that supplies power to the heating resistor 3.

In the present embodiment, as shown in the figure, each heating resistor 3 in the thermal head is provided with one or more layers so that the resistance value of each heating resistor 3 in the thermal head varies randomly. A pattern of at least one layer of each layer formed in a multi-layer structure, except for a film formed in the multi-layer structure and formed at the end of the multi-layer film and closest to the recording medium during actual recording. The sheet resistance of the heating resistor is adjusted by changing the shape. FIG. 5 shows the distribution of resistance values of the thermal head according to this embodiment.

As a result, in the resistance value distribution of the thermal head of the present invention, the resistance value of each dot varies randomly with a finer step size, so that the boundary between blocks in the resistance value distribution varies. Since they are hidden, the boundaries between blocks do not appear clearly.

As a result, the connection of the electric circuit, the structure,
Even when divided into at least two blocks from the viewpoint of handling, the difference in the printing state between the blocks recorded on the recording medium during actual printing is A thermal head has been realized which is capable of recording evenly enough to be imperceptible.

[0021]

As described above, in the case of the conventional thermal head, at the time of actual printing, a difference in the printing of the boundaries between the blocks occurs at the boundary of the blocks, which is sufficiently perceptible by human eyes. However, since the state of printing is clearly different between blocks so that the existence of blocks is confirmed, uniform printing cannot be realized on the entire surface of the recording medium. Since the resistance value of each dot of the thermal head is randomly varied as appropriate, the boundary between blocks is hidden in the variation in the resistance value distribution, so that the boundary between blocks does not appear clearly.

As a result, the wiring of the electric circuit, the structure,
Even when divided into at least two blocks from the viewpoint of handling, the difference in the printing state between the blocks recorded on the recording medium during actual printing is There is an effect that it is possible to realize a thermal head capable of recording uniformly enough to be unrecognizable.

[Brief description of drawings]

FIG. 1 is a partial plan view of a main part of a general thermal head.

FIG. 2 is a sectional view of an embodiment of the present invention corresponding to AA ′ in FIG.

FIG. 3 is an explanatory diagram showing a state of resistance value distribution of the thermal head of the present invention.

FIG. 4 is a sectional view showing a thermal head of another embodiment of the present invention, which corresponds to AA ′ in FIG.

FIG. 5 is an explanatory diagram showing a state of resistance value distribution of the thermal head of the present invention.

FIG. 6 is a sectional view showing a conventional thermal head.

FIG. 7 is an explanatory diagram showing a state of resistance value distribution of a conventional thermal head.

FIG. 8 is an explanatory diagram showing steps of the method for manufacturing a thermal head of the present invention.

[Explanation of symbols]

 1 base material such as ceramic material 2 glass glaze layer 3 heating resistor 4 power supply body for supplying power to heating resistor

Claims (3)

[Claims] 1. A base having a glass glaze layer formed on a substrate such as ceramics, a plurality of heating resistors arranged in parallel on the glass glaze layer, and a power feeding body for supplying electric power to the heating resistors. In the thermal head, by increasing or decreasing the sheet resistance value of each of the heating resistors,
A thermal head characterized in that individual resistance values of the heating resistors arranged in parallel are appropriately varied. 2. The heating resistor is formed in a multilayer film structure including one or more layers, and the sheet resistance of the heating resistor is adjusted by changing the film structure of the multilayer film. The thermal head according to claim 1. 3. The heating resistor is formed in a multilayer film structure of one or more layers, and except for a film formed at the end of the multilayer film and located at a position closest to the recording medium during actual recording. 2. The thermal head according to claim 1, wherein the sheet resistance of the heating resistor is adjusted by changing the pattern shape of the film of each layer.