JP3233694B2 - Thermal head - Google Patents

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 for a thermal transfer printer, a facsimile or the like.

[0002]

2. Description of the Related Art FIGS. 5 (a) and 5 (b) are a structural sectional view and a structural top view showing a schematic configuration example of a printing section of a fusion type thermal transfer printer using a conventional partial glaze thermal head, and FIG. FIG. 2 is an enlarged sectional view showing a schematic configuration example of a partial glaze thermal head. FIG. 5 (a)
Is a sectional view taken along the line AA ′ of FIG. In these figures, 1 is an alumina substrate made of Al ₂ O ₃ , 2 is a glaze glass portion, 3 is a high-resistance heating resistor portion made of, for example, Ta ₂ N or TaSiO ₂ , and 4 is a contact with the heating resistor portion 3 The common electrodes 5 and 5 are individual electrodes that are in contact with a part of the heating resistor 3, and 6 is a protective film that covers the heating resistor 3, the common electrode 4, and the individual electrode 5. Reference numerals 1 to 6 constitute a partial glaze thermal head 7.

Further, reference numeral 8 denotes a partial glaze thermal head 7
A base layer 9 made of a polyester film in contact with the base layer 8; an ink layer adhered to the base layer 8;
These components 8 and 9 constitute the ink film 10. Further, reference numeral 11 denotes a sheet in contact with the ink film 10, and reference numeral 12 denotes a platen which contacts the sheet 11 and conveys the sheet 11 by its rotation.

In FIG. 5 (b), reference numeral 13 denotes an insulator for separating the heating resistor 3 from the individual electrode 5, and 14 denotes a control I for controlling on / off of the voltage of the individual electrode 5.
C and 15 indicate electric signals corresponding to print data to be printed,
A signal line supplied from the control unit of the printer body to the control IC 14.

In general, a character printed by a thermal transfer printer is a set of dots (hereinafter, referred to as dots), and one character is divided into a plurality of rows and printed one by one. Further, one row is a set of a plurality of dots (hereinafter, a set of dots).
Dot), and each dot is printed simultaneously. Based on this printing method, in the thermal transfer printer having the structure shown in FIGS.
A process of printing (a set of one dot) on the paper 11 will be described.

First, the paper 11 is moved by the rotation of the platen 12 to a position where the dot array of the partial glaze thermal head 7 is printed. Next, an electric signal corresponding to the dot row to be printed is sent from the signal line 15 to the control IC 14.
Supplied to As a result, the control IC 14
On / off of the voltage of the plurality of individual electrodes 5 is controlled based on the supplied electric signal. Therefore, the heating resistor portion 3 between the plurality of turned-on individual electrodes 5 and the common electrode 4 conducts and generates heat. The heat of the heating resistor portion 3 generated by the heat generation is transmitted to the adjacent protective film 6 and is transmitted to the ink film 10 in contact with the protective film 6. Thereby, the ink layer 9 in the high temperature portion of the ink film 10 is formed.
Is melted, and the ink is transferred to the paper 11 that is in contact.

If there are no individual electrodes 5 turned on (all the individual electrodes 5 are off), the heating resistor 3 does not generate heat and the ink layer 9 does not melt. Is not transcribed. As described above, the dot row is printed on the paper 11.

In the above description, an example is shown in which a partial glaze thermal head 7 is used as a thermal head for a thermal transfer printer. The thermal head includes a full glaze thermal head having the structure shown in FIG. And the like. In these drawings, parts corresponding to the respective parts in FIGS. 5 and 6 are denoted by the same reference numerals, and description thereof will be omitted. However, the operation of these thermal heads is the same as that of the above-described partial glaze thermal head 7, and therefore the description thereof is omitted. The details of the thermal head having the structure shown in FIG. 8 are described in Japanese Utility Model Application Laid-Open No. 62-70026 previously proposed by the present applicant.
Please refer to the specification and drawings attached to the request for the issue.

[0009]

By the way, in the above-mentioned conventional thermal head, the heat generated by the heating resistor portion 3 is transmitted to a wide portion of the protective film 6 via the common electrode 4 or the individual electrode 5. Is done. Therefore, assuming that the advancing direction of the thermal head 10 with respect to the paper 11 is the “head advancing direction”, finally, as shown in FIG.
Melt length B) is the ideal value.
Further, there is a disadvantage that the length of the printed dot in the head traveling direction (hereinafter, referred to as a printing length) becomes larger than an ideal value.

Therefore, conventionally, in order to solve the above-mentioned drawback, the thermal head 10 is stopped at regular intervals for heat radiation so that the temperature of the entire thermal head 10 does not become higher than a predetermined value. However, this method has a disadvantage that the printing speed is reduced. The present invention has been made under such a background, and without reducing the printing speed, the range in which the ink in the ink layer is melted is brought close to the ideal range, so that the shape of the printed dot is ideal. It is an object of the present invention to provide a thermal head that can be formed into a general shape.

[0011]

In order to solve the above-mentioned problems, a thermal head according to the present invention employs an ink jet printer.
Used to heat the film to transfer dots to paper
A first thermal head having a predetermined depth on the upper surface.
Glaze glass in which second and concave portions are formed at predetermined intervals
And a position between the first and second recesses and the recesses.
Over the convex part of the glaze glass
And the heating resistor formed so as to face the convex portion.
The first and second recesses on the heating resistor;
Individual electrodes and common electrodes respectively formed in the
Formed on the heating resistor, the individual electrodes, and the common electrode
Wherein the first and second protective films are provided.
Protective film on the individual electrode and the common electrode in the concave portion
And a gap provided between the ink film and the ink film.
And

[0012]

According to the above-described thermal head, when a voltage is applied to an individual electrode, the individual electrode, the heating resistor, and the common electrode conduct, and the heating resistor generates heat. The heat generated in the heating resistor is conducted to the adjacent convex portion of the protective film having the unevenness, and also to the common electrode and the individual electrode adjacent to each other. The heat conducted to the projections of the protective film is conducted to the base layer of the ink film holding the ink, and the heated portion of the ink is transferred to the paper.

On the other hand, the heat conducted to the common electrode and the individual electrodes is conducted to the concave portions of the protective film laminated on the electrodes. However, since the concave portion of the protective film is not in contact with the base layer of the ink film, the heat conducted to the concave portion of the protective film is not conducted to the base layer of the ink film.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a structural sectional view showing a schematic configuration of a printing unit of a thermal transfer printer to which a thermal head 16 according to an embodiment of the present invention is applied, and FIG. 2 is a structure showing dimensions of respective parts of the thermal head 16 according to an embodiment of the present invention. FIG. 3 is a sectional view showing the shape of dots printed on paper by the thermal head of the present embodiment. In these figures, portions corresponding to the respective portions in FIG. 5 and portions common to these drawings are shown. Are denoted by the same reference numerals, and description thereof is omitted.

In the thermal head 16 shown in FIG. 1, convex portions 17a and concave portions 17b are formed at predetermined intervals and a predetermined depth on the upper surface of the glaze glass portion 17, and a heating resistor is formed on these convex portions 17a and concave portions 17b. A part 18 is formed. Further, a common electrode 19 and an individual electrode 20 are formed on the heating resistor portion 18 with a dot forming portion 18a formed on the convex portion 17a for forming dots on the paper 11 interposed therebetween. That is, the common electrode 19 and the individual electrode 20 are both formed on the heating resistor portion 18 formed on the concave portion 17b. Further, a protective film 21 for protecting the heating resistor portion 18, the common electrode 19, and the individual electrode 20 is formed thereon. As a result, the dot forming portion 18a of the heating resistor portion 18 comes into contact with the ink film 10 via the protective film 21, and the common electrode 19 and the individual electrodes 20 formed on both sides of the dot forming portion 18a and the ink film 10 , A void 22 is formed via a protective film 21.

In FIG. 2, the thickness ta of the alumina substrate 1 is, for example, 0.635 mm, the thickness tb of the glaze glass portion 17 is, for example, 50 μm,
The depth tc and the length td of 7b are, for example, 3 μm and 130 μm, and the length te of the projection 17a is 100 μm. In this case, the length te of the dot forming portion 18a is made to coincide with the ideal melting length A. The convex portion 17a and the concave portion 17b of the glaze glass portion 17 are formed on the glaze glass portion 17 by, for example, a method using an etching technique using buffered fluorine or a thick film manufacturing technique. Screen paste of glass paste
It can be formed by a known method such as a method of firing at about 0 ° C.

The resistance value of the heating resistor portion 18 is, for example, 1500Ω, and the common electrode 19 and the individual electrode 20 are connected.
Is formed of, for example, aluminum having a thickness tf of 1.5 μm. The protective film 21 is formed of, for example, an SiO ₂ layer having a thickness of ₂ μm and a Ta ₂ O ₅ layer having a thickness of 3 μm, and has a thickness tg of 5 μm. In FIG. 3, reference numeral 23 denotes a dot to be printed on the paper 11, L denotes the length of the dot forming unit 18a, W denotes the width of the dot forming unit 18a, L ′ denotes the printing length of the dot 23, and W ′ denotes This is the printing width of the dot 23.

In such a configuration, when an electric signal representing a dot row to be printed is supplied to the control IC 14, the control IC 14 is controlled based on the supplied data.
14 turns on a plurality of individual electrodes 20 from zero. Therefore, the heating resistor portion 18 between the turned-on individual electrode 20 and the common electrode 19 conducts and generates heat, so that the heat generated from the heating resistor portion 18 is transferred to the protrusion 21 a of the protective film 21 and the common electrode 19. 19 and the individual electrodes 20. As a result, the heat of the protrusions 21 a of the protective film 21 is conducted to the ink sheet 10 that is in contact, and the heat conducted to the common electrodes 19 and the individual electrodes 20 is conducted to the recesses 21 b of the protective film 21.

However, since there is a gap 22 between the concave portion 21b of the protective film 21 and the ink film 10, the heat of the concave portion 21b of the protective film 21 is not conducted to the ink film 10. Therefore, the melt length B of the ink film 10
Is substantially equal to the length of the dot forming portion 18a and is a value close to the ideal melting length A. Then, the melted portion of the ink layer 9 is transferred to the paper 11 in contact. At this time, FIG.
The printing length L 'of the dot 23 shown in FIG.
When there is no individual electrode 20 turned on, the ink is not transferred to the paper 11 as in the conventional technique.

As described above, according to the above-described embodiment, the melt length B can be made closer to the ideal melt length A, and the print length L 'can be made closer to the ideal value. In addition, since the heat of the extra portion of the thermal head 16 is not conducted to the ink film 10,
As shown in the graph of (a), even if the heating power of the heating resistor portion 18 increases, the aspect ratio (print width W ′ / print length L ′) of the printed dot size does not easily decrease. That is, there is an effect that the dots are not easily deformed even when the heat generation power increases.

Further, since the heat conduction between the thermal head 16 and the ink film 10 is minimized, it is applied to the heating resistor 18 as shown in the graph of FIG. Even if the power is small, it has an effect that dots can be printed with a high ink density. In this embodiment, an example in which the thermal head according to the present invention is applied to a fusion type thermal transfer printer has been described. However, it goes without saying that the present invention can be applied to a sublimation type thermal transfer printer.

[0022]

As described above, according to the present invention,
There is an effect that the range in which the ink in the ink layer melts can be made closer to the ideal range, and the dot shape can be made an ideal shape. Further, since it is not necessary to stop the operation of the thermal head for heat radiation, there is an effect that the printing speed does not decrease.

[Brief description of the drawings]

FIG. 1 is a structural sectional view showing a schematic configuration of a printing unit of a thermal transfer printer to which a thermal head according to an embodiment of the present invention is applied.

FIG. 2 is a structural sectional view showing dimensions of each part of a thermal head according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating an example of the shape of a dot printed on a sheet.

FIG. 4 is a characteristic diagram illustrating an example of characteristics of a printed dot.

FIG. 5 is a structural sectional view showing a schematic configuration example of a printing unit of a thermal transfer printer using a conventional partial glaze thermal head.

FIG. 6 is an enlarged sectional view showing a schematic configuration example of a conventional partial glaze thermal head.

FIG. 7 is an enlarged structural sectional view showing a schematic configuration example of a conventional full glaze thermal head.

FIG. 8 is an enlarged structural sectional view showing a schematic configuration example of a previously proposed thermal head.

FIG. 9 is a diagram illustrating an example of a melted portion of ink with respect to a partial glaze thermal head.

[Explanation of symbols]

 7: Partial glaze thermal head 8: Base layer 10: Ink film 14: Control IC 15: Signal line 16: Thermal head 17: Glaze glass (glaze glass) 18: Heating resistor (heat generation) 18a dot forming section 19 common electrode 20 individual electrode 21 protective film 22 void 23 dot

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takehisa Konishi 4-10-1, Funatari, Itabashi-ku, Tokyo Japan Metal Co., Ltd. (56) References JP-A-62-167057 (JP, A) 3-73364 (JP, A) JP-A-58-122885 (JP, A) JP-A-58-50945 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 2/335

Claims (1)

(57) [Claims] 1. An ink film is heated to form dots on paper.
A thermal head used for transfer to a substrate, wherein first and second concave portions having a predetermined depth are formed at predetermined intervals on an upper surface.
The formed glaze glass, and the first and second recesses are located between the recesses.
Formed on the upper surface of the glaze glass over the convex portion.
On the heating resistor so that the heating resistor is opposed to the heating resistor with the convex portion interposed therebetween.
And formed in the first and second recesses, respectively.
An individual electrode and a common electrode are formed on the heating resistor, the individual electrode, and the common electrode.
And a protective film formed, wherein the individual electrodes and the individual electrodes in the first and second recesses are provided.
A gap between the protective film on the common electrode and the ink film
A thermal head comprising: