JPH0431065A - Thermal head - Google Patents

Abstract

PURPOSE:To prevent slacking and wrinkling of an ink sheet from occurring and to prolong the life of the ink sheet by a method wherein a first individual electrode and a second individual electrode are placed facing each other with a main line of a common electrode placed in between. CONSTITUTION:With electric current supplied between a specified first individual electrode 22 and a common electrode 21, a first heat-generating resistance body 11 heats up. Then ink on an ink sheet is transferred by this heat to a recording sheet, forming dots, After the recording sheet is fed by a length equivalent to the distance (l) between the first heat-generating resistance body 11 and a second heat-generating resistance body 12, electric current is supplied between a second individual electrode 23 facing the first individual electrode 22 an the common electrode 21, and a section corresponding the electrification of the second heat-generating resistance body 12 heats up. Thereby the ink on the ink sheet is transferred to the recording sheet, forming the dots.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal head used in, for example, a sublimation type thermal printer.

[Prior Art] FIG. 6 is a plan view showing the main parts of a conventional thick-film thermal head disclosed in, for example, Japanese Patent Laid-Open No. 1-180362, and FIG. 7 is taken along the line ■-■ in FIG. It is a cross-sectional view in the direction of arrows, and the sixth
The figure excludes the wear-resistant layer.

In the figure, (1) is a ceramic substrate, (3
) is a heating resistor, (4) is a common electrode, and this common electrode (4) is connected perpendicularly to the heating resistor (3) at equal intervals in the length direction of the heating resistor #(3). It has a large number of electrode supports 1i (4a). (5) is the board (1)
The individual electrodes (5) are connected to the heating resistor (3) orthogonally in the middle of the adjacent electrode branch lines (4a), and each of the individual electrodes (5) is connected to the IC (Fig. (not shown). (6) is a wear-resistant layer covering the surface portion.

In the conventional thermal head configured as described above, during printing, an ink sheet (not shown) and paper (not shown) are sent between the wear-resistant layer (6) and the platen roller (7). . In this state, a large number of individual electrodes (5
) are made conductive to the power supply. Control of such individual electrodes (5) is performed by an IC. On the other hand, since the common electrode (4) is always connected to a power source (not shown), the predetermined individual electrode (5) and the common electrode (4)
) current flows only between As a result, the heating resistor (3) in the portion where the current flows generates heat, and this heat causes the ink on the ink sheet to be transferred onto the paper as dots.

Next, FIG. 8 is a plan view showing the main parts of another conventional thick film thermal head disclosed in the same publication as FIG. The first and second heating resistors (13) are arranged in parallel with an interval l, and the first and second heating resistors (11), (
12), and this common electrode (13) is connected to the first electrode support 1m (13a) orthogonally to the first heating resistor (11), and The second electrode branch line (13b) connected orthogonally to the second heating resistor (12) is connected to each heating resistor (11), (1
2) They are arranged alternately at equal intervals in the length direction.

(14) is a first electrode branch line (13a) connected perpendicularly to the first heating resistor (11) between adjacent first electrode branch lines (13a).
(15) is the adjacent second electrode branch line (13b
) is a second individual electrode connected orthogonally to the second heating resistor (12). Further, the first and second individual electrodes (14) and (15) are each connected to an IC (not shown) and are individually controlled.

In the conventional thermal head as described above, a current is passed between a predetermined first individual electrode (14) and a common electrode (13), and the first heating resistor (11) in that part generates heat. . This heat causes the ink on the ink sheet to be transferred onto the paper as dots. Thereafter, the paper is fed by the distance l between the first and second heating resistors (11) and (12), and the second individual electrode (14) corresponding to the first individual electrode (
15) and the common electrode (13), and the second heating resistor (12) in that portion generates heat. As a result, the ink on the ink sheet is transferred onto the paper as dots.

At this time, in the thermal head as described above, the first and second electrode branch lines (13a) and (13b) are connected to the common electrode
Since the dots are provided alternately on both sides of the first heating resistor (11) and the second heating resistor (12),
) will have an appropriate overlap with the dots. Therefore, it is possible to perform printing without gaps between dots as compared to those shown in FIGS. 4 and 5.

Next, FIG. 9 is a plan view showing essential parts of a conventional thin film thermal head, and FIG. 10 is a cross-sectional view taken along the line XX in FIG. 9. Further, FIG. 11 is a plan view of a main part showing another conventional example of the thin film type thermal head shown in FIG. 9, and the wear-resistant layer is excluded in FIGS. 9 and 11.

The thermal head shown in FIG. 9 performs printing in the same manner as in FIG. 6, and the thermal head in FIG. 11 performs printing in the same manner as in FIG. 8.

Note that (2) is a glaze layer as a heat insulating layer provided on the substrate (1).

[Problems to be Solved by the Invention] In the conventional thermal head configured as described above, especially when used in a sublimation type thermal printer, in order to sufficiently transfer the ink on the ink sheet onto the paper, It is necessary to apply quite high energy. However, when such high energy is applied to the thermal head, as shown in FIGS. 12 and 13, the ink sheet (20) becomes loose and wrinkled, white spots appear in the print, and the thermal There were problems such as a shortened lifespan of the head itself. Also, to avoid this,
There was a problem that if high energy was not applied, insufficient concentration would occur. Furthermore, in the cases shown in Figures 8 and 11, some of the dots overlap, so although the density is somewhat high, there is a problem that the print may become unclear, especially when printing characters. there were.

This invention was made with the aim of solving the above-mentioned problems, and it is possible to sufficiently increase the density of a print without applying high energy or impairing the clarity of the print. It is an object of the present invention to provide a thermal head which can thereby prevent the ink sheet from becoming loose or wrinkled and can extend its life.

[Means for Solving the Problems] A thermal head according to the present invention has a first individual electrode and a second individual electrode facing each other with a common electrode main line in between.

[Operation] In this invention, after the first heating resistor is made to generate heat and the dots are transferred, the paper is fed by the distance between the first and second heating resistors, and the second heating resistor is made to generate heat. As a result, the dots are transferred in an overlapping manner at the same position as on the first heating resistor.

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

FIG. 1 is a plan view showing the essential parts of a thick-film thermal head according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIGS. The same or equivalent parts as in FIG. 11 are given the same reference numerals, and their explanations will be omitted.

In addition, the wear-resistant layer is not shown in FIG.

In the figure, the symbol (21) is a common electrode, and this common electrode (21) is connected to the first and second heating resistors (11).
, (12), the common electrode main line (21a
), and a large number of first electrode branch lines (21b) branched from the common electrode main line (21a) at predetermined intervals in the length direction and connected orthogonally to the first heating resistor (11).
and the first electrode branch line (21b) of the common electrode main line (21a).
) are branched from the same location and connected orthogonally to the second heating resistor (12).
).

(22) is a first individual electrode connected between adjacent first electrode branch lines (21b) orthogonally to the first heating resistor (11). pole, (23) is the adjacent second electrode branch line < 21c)
The first individual electric wire [! The second individual facing (22)! and these first and second individual electrodes (22), (23)
) are each connected to an IC (not shown).

In the thermal head configured as described above, first, a current is passed between a predetermined first individual electrode (22) and a common electrode (21), and the first heating resistor (1
1) generates heat. Then, due to this heat, the ink on the ink sheet is transferred as dots onto the paper. Next, the distance l between the first and second heating resistors (11) and (12) is increased.
After the paper has been fed by the amount of paper, a current is passed between the second individual electrode (23) facing the first individual electrode (22) and the common electrode (21), and the second Heat generating resistor (1
2) generates heat. As a result, the ink on the ink sheet is transferred onto the paper as dots.

Next, FIG. 3 is a plan view showing the main parts of a thin film type thermal head according to another embodiment of the present invention, and FIG.
3 is a cross-sectional view taken along line 3, and the wear-resistant layer is excluded in FIG. 3.

In such a thin film thermal head, the first individual electrode (22) is connected to the first heating resistor (11), and its tip end is connected to the first electrode branch line (21).
b> is opposed to the tip. In addition, a second individual electrode (
23) is connected to the second heating resistor (12), and its tip faces the tip of the second electrode branch line (1lc). And the common electrode main line (21a)
The entire structure is arranged symmetrically around the center.

Further, as shown in FIG. 4, the thin film thermal head of this embodiment has first and second heating resistors (11), (
12) is directed toward the axis of the platen roller (7), and the wear-resistant layer (6) on the surface is directed toward the axis of the platen roller (7).
) is gently curved in a concave shape along the outer circumferential surface of the

Even in the thin-film type thermal head as described above, printing is performed by the same operation as in the thick-film type.

In both the thick film type and thin film type thermal heads shown in the above embodiments, the common electrode (21) and the first and second individual electrodes (22) and (23) are connected to the first and second individual electrodes (22) and (23). Since the heating resistors (11) and (12) are arranged in a line-symmetrical manner, the dots on the paper are transferred to the same position twice, resulting in a higher height. The density of the print can be made sufficiently high without applying energy and without compromising sharpness. Furthermore, since the applied energy is low, the ink sheet is prevented from becoming loose or wrinkled, and the life of the thermal head itself is extended.

Furthermore, Fig. 5 is a relationship diagram showing the relationship between applied energy and head life, and the relationship between applied energy and print density, respectively.As shown by the broken line curve in the figure, sufficient density can be achieved with - times of printing. To obtain this, it is necessary to apply an energy of E5, but as shown by the dashed-dotted curve in the figure, it is sufficient to apply an energy of E for two printings, and when the applied energy is Eb, Compared to E, the head life is considerably extended as shown by the solid curve in the figure.

Note that the thermal head of the present invention can be applied to both melt-type printers and sublimation-type printers.

[Effects of the Invention] As explained above, in the thermal head of the present invention, the first and second heating resistors are provided in parallel with each other at intervals, and the space between the first and second heating resistors is The common electrode and the first and second individual electrodes are arranged so as to be symmetrical about the center, and the dots are superimposed and transferred at the same position on the paper, so that high energy can be applied. It is possible to make the density of the print sufficiently high without compromising the clarity of the print, thus preventing the ink sheet from becoming loose or wrinkled, and prolonging its lifespan. play.

[Brief explanation of drawings]

FIG. 1 is a plan view showing one embodiment of the present invention, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is a plan view showing another embodiment of the invention. Figure 4 is a cross-sectional view taken along the line ■-■ in Figure 3, Figure 5 is a relationship diagram showing the relationship between the energy applied to the thermal head, head life, and print density, and Figure 6 is the first conventional example. A plan view showing an example, FIG. 7 is a sectional view taken along the line ■-■ in FIG. 6, FIG. 8 is a plan view showing the second conventional example, and FIG. 9 shows the third conventional example. 10 is a sectional view taken along line X-X in FIG. 9, FIG. 11 is a plan view showing the fourth conventional example, and FIG. 12 is a perspective view showing a conventional ink sheet. Figure 13 is the 12th
It is an arrow sectional view along the XI-XI line of a figure. In the figure, 1) is the substrate, 11) is the first heating resistor, (12) is the second heating resistor, (21) is the common electrode, and (21a) is the common! The seed main line, (21b) is a first electrode branch line, (21c) is a second electrode branch line, (22) is a first individual electrode, and (23) is a second individual electrode. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Scope of claims]
and a second heating resistor, a common electrode main line provided between the first and second heating resistors, and a common electrode main line branched from the common electrode main line at a predetermined interval in the length direction. a plurality of first electrode branch lines connected to one heating resistor; and a plurality of second electrode branch lines branched from the same point as the first electrode branch line of the common electrode main line;
a common electrode having a large number of second electrode branch lines connected to the heating resistor;
a first individual electrode connected to the heating resistor; and a first individual electrode facing the second electrode branch line and connected to the second electrode branch line.
A thermal head comprising: a second individual electrode connected to the heating resistor, and facing the first individual electrode with the common electrode main line in between.