JPH02305655A - Thermal head - Google Patents

Abstract

PURPOSE:To eliminate a gap between a heating resistor layer and an ink to ensure a thermal transfer by a method wherein, when an electrode is connected to a slant surface of a heating resistor layer formed by raising a glaze layer, a face end thereof which is not in contact with the heating resistor layer is provided with step parts. CONSTITUTION:A common electrode 14 and discrete electrodes 15 are formed by etching. At this time, conductors 14b, 15b formed on conductors 14a, 15a abutting on the slant faces of a heating resistor layer 4 formed by raising a glaze layer 3 are formed longitudinally shorter than the conductors 14a, 15a by the length of step parts 13 with respect to a paper surface. Moreover, conductors 14c, 15c as next layers are also formed shorter than the conductors 14b, 15b by the length of step parts 13. In this manner, in a printing state by a thermal head 10, a gap between a protective layer 7 just on the heating resistor layer 4 and a base film 16a is eliminated. Therefore, a thermal conduction from the heating resistor layer 4 to an ink sheet 16 is improved, and the pressing force of a platen 18 is directly applied to a melting position of an ink 16b. Thus, the thermal transfer of the ink 16b to printing paper 17 is ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a structure that improves the adhesion between a heating element and a heated body of a thermal head.

[Conventional technology]

Figure 3 is, for example, the first example of
FIG. 4 is a cross-sectional view of the conventional thermal head shown in the figure, and FIG. 4 is a cross-sectional view showing the state of printing by the thermal head.

In the figure, (l) is a thermal head, (2) is an insulating substrate made of ceramic or the like, (8) is a glaze layer formed on the insulating substrate (2), and (4) is on the glaze layer (8). The heating resistor layer (6) is formed in the heating resistor layer (4).
), the common electrode (6) is an independent electrode, and a heat generating resistor layer (4) is connected in series between the common electrode (5) and a pulse current is applied from a printing control circuit (not shown). A predetermined heating resistor layer (4) is made to generate heat at a predetermined timing. (A) shows the heating resistor layer (4), the common electrode (5)
), a protective layer produced over the independent electrode (6).

Generally, between the common electrode (5) and the independent electrode (6), a stain electrode is carved by etching to expose the heating resistor layer (4), and then a protective layer (such as glass) is sputtered on top of this.
γ), a recess (8) is generated.

The print made with this conventional thermal head (1)! ! will be explained with reference to FIG. In FIG. 4, utll is an ink sheet consisting of a base film (16a) and ink (16b). CI? ) is photographic paper, (181 is a platen. The thermal head (1) is platen fI8 with an ink sheet tm and photographic paper C1η interposed)
The heat-generating resistor layer (4) is heated by the pulse energization from the print control circuit, and the heat from the lever causes the ink sheet σ to
The ink (16b) of e is melted and thermally transferred to photographic paper (L7).

[Problem to be solved by the invention]

In the conventional thermal head as described above, during thermal transfer printing, the thermal head (1) is pressed against the platen (181) due to the recess (8), but a gap (2) is created. ) and prevent heat conduction from the ink (1
6b) is not sufficiently melted, resulting in insufficient thermal transfer of the ink (16b) to the photographic paper αη. Also, due to the protrusions on both sides of the recess (8), pressure is applied to the melting point of the ink (16k)). There was a problem that it was insufficient. As a measure to eliminate the above-mentioned void, a double partial glaze thermal head as shown in FIG.
There have also appeared products in which the protective layer (γ) is ground flat, as shown in Japanese Patent No. 173265, but these types are difficult to manufacture and expensive.

This invention was made in order to solve the above-mentioned problem, and the recess (8) is made smaller to reduce the gap caused by the recess (8).
There is no generation of ink (16) from the heating resistor layer (4).
An object of the present invention is to provide an inexpensive thermal head that can reliably perform thermal transfer without hindering heat conduction to (b).

[Means to solve the problem]

In the thermal head according to the present invention, a stepped portion is formed at the end of the surface of the electrode connected to the rising slope of the heat generating resistor layer formed by the glaze layer and not in contact with the heat generating resistor layer.

[Effect]

In this invention, the stepped portion formed at the end of the surface of the electrode that does not contact the heat generating resistor layer suppresses protrusion of the electrode edge due to the bulging of the glaze layer, reduces the concave portion, and allows the heat generating resistor layer to interact with the ink. Eliminate air gaps that impede heat conduction between

〔Example〕

FIG. 1 is a sectional view of a thermal head showing an embodiment of the present invention, and FIG. 2 is a sectional view showing the state of printing by the thermal head.

In the figure, (2) to (5), (γ), σθ to (1
& is the same as that explained in the above conventional example. σ is a thermal head, σ (a) is a common electrode connected to the heating resistor layer (4), and conductors (14a) to (14c)
) is formed by laminating layers. (It is an independent electrode, and a heat generating resistor layer (4) is connected in series between it and the common electrode a4, and a predetermined heat generating resistor layer (4) is connected by pulse energization from a printing control circuit (not shown). Generate heat at a predetermined timing.The independent electrode α9 connects the conductors (15a) to (
15c).

Generally, the common electrode (141) and the independent electrode (19) are formed by etching.At this time, the conductors (15a) and (14a) are in contact with the inclined surface of the heating resistor layer (4) due to the rise of the glaze layer (8). The next layer of conductor (
14b).

(15b) is formed to be shorter in the horizontal direction with respect to the plane of the paper by step H (131), and the next layer of conductors (14c), (1
5c) also has conductors (14b) and (15b) only at step 0.
It is formed very short.

This makes it possible to suppress the protrusion of the electrode edge near the top of the glaze layer (8) of the common electrode α4 and the independent electrode σ9, and even if the protective layer (γ) is formed on top of this, it will not be possible to The recess can be made extremely small compared to the head (1).

The state of the print made by the thermal head of this embodiment is shown in the second example.
1. As there is no gap between the protective layer (7) directly above the heating resistor layer (4) and the base film (16a), the heating resistor layer (4)
Heat conduction from the ink sheet (1119) to the ink sheet (1119) is good, and since the pressing pressure on the platen U is directly applied to the melting point of the ink (16b), the thermal transfer of the ink (16b) to the photographic paper αη is reliably performed.

〔Effect of the invention〕

As explained above, according to the present invention, the stepped portion formed at the edge of the surface of the electrode which is not in contact with the heating resistor layer of the electrode where the top of the heating resistor layer formed by the glaze layer is connected to the side surface is the glaze layer. This suppresses the protrusion of the electrode edge due to the swelling force of the recess, which reduces the size of the recess and eliminates the gap caused by the recess, resulting in good heat conduction from the heating resistor layer to the ink transfer, and a low-cost thermal head that can reliably transfer heat. can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a thermal head showing an embodiment of the present invention, FIG. 2 is a cross-sectional view showing the state of printing by the thermal head, FIG. 3 is a cross-sectional view of a conventional thermal head, and FIG. A cross-sectional view showing the state of printing by a conventional thermal head. FIG. 5 is a cross-sectional view of another conventional thermal head. In the figure, (2) is an insulating substrate, (8) is a glaze layer,
(4) is the heating resistor layer, (A) is the protective layer, α3 is the stepped portion,
σ4 is a common electrode, (14a) to (14C), (1
5a) to (15c) are conductors. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] A heating resistor layer formed on a glaze layer formed on an insulating substrate; an electrode connected to the raised slope of the heating resistor layer formed by the glaze layer to conduct electricity to the heating resistor layer; and an electrode on the slope. A thermal head comprising: a stepped portion formed at an end of the surface not in contact with the heating resistor layer to suppress protrusion of the electrode edge due to the swell of the glaze layer and the thickness of the electrode.