JPS61295057A - Thermal head and its preparation - Google Patents

Abstract

PURPOSE:To attain miniaturization and the extension of life and to enable high grade recording, by forming a second heat generating resistor having a length corresponding to that of the heat generating resistor row on the other surface of a flexible insulating substrate at a position except said heat generating resistor row. CONSTITUTION:A heat resistant org. film, for example, a polyimide film 11 is used as a flexible insulating substrate and a membrane resistor film 12 is adhered to one surface of said film 11 and leads 13 are laminated and adhered to said resistor film 13 by vacuum vapor deposition. Patterns are formed by photoetching to form a heat generating resistor row 14 and an abrasion protective film 15 is adhered thereto. Next, a resistor film is adhered to the other surface of the polyimide film 11 and a strip like heat generating resistor 16 is formed by photoetching so as to make the length thereof almost equal to that of the resistor row and to be almost parallel to said resistor row in the inlet side of recording paper. Lead electrodes 17 are provided to both terminals of the resistor film and insulated by coating an insulating resin 18 except the take-out parts thereof. Next, the insulating substrate is adhered to a heat dissipating plate 20 comprising a metal having good heat conductivity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a thermal head 6i in which a row of heating resistors is formed on a RIF flexible substrate 1-, and a method for manufacturing the same.

[Technical background of the invention and its problems]

-Remal Print 1 The head is installed in a facsimile or other recording device, and supplies λ characters and image information to thermal paper or a thermal ink ribbon as heat No. 64, and records the information on the surface of the thermal paper. The head has a structure in which a large number of heating resistors with wires connected to both ends are arranged in parallel on the surface of the absolute M support plate, arranged in a line shape, and the head is perpendicular to the line. Thermal paper is fed from the JJ direction and brought into thermal contact with I7.

Conventionally, the insulating substrate of a thermal head is generally made of a hard ceramic plate such as alumina.
The contact of the thermal paper with the heating resistor formed at - is 1°.
-5), making it difficult to reproduce high-quality characters. For this reason,
Attempts have been made to make the heating resistor part protrude from the insulating substrate or to form the insulating substrate into a semicylindrical shape (circular shape), but due to the poor ilZ surface properties, the heating resistor formed by the method such as Body side spear-1 (It had the drawback that it was not practical because it was difficult to form a pattern of line groups, which caused problems in manufacturing.

The solution to this problem was the use of a flexible insulating substrate (see Japanese Patent Laid-Open No. 131576/1983). That is, for patterning the heating resistor array and the wire group, the flexible insulating substrate is made into a 111-plane shape, and when used as an actual head, the substrate is placed along a cylindrical or circular support. It has a structure in which a row of deflectable heating resistors is located on the top surface.

However, as a heat-resistant flexible insulating substrate, there is an organic film 12 such as polyimide, but since it is a synthetic resin, its heat resistance is different, and it cannot withstand the peak temperature of the heating resistor. Although it is made to have a high density, there is an inconvenience that it becomes difficult to take out the lead wire of the non-ql surface (I).

[Object 1 of the invention] The present invention has been made in consideration of -1-.
The present invention provides a thermal head that has a long life and can perform high quality recording, and a method for manufacturing the same.

[Summary of the invention]

The present invention provides a thermal head in which a heat-generating resistor array is formed on the surface of a flexible insulating substrate made of a heat-resistant organic film, and a heat-generating resistor is connected to the heat-generating resistors on the other surface of the flexible insulating substrate. The thermal head is provided with a second heat generating resistor having a length corresponding to the heat generating resistor row at a position other than directly below the row.

By positioning a second heating resistor in parallel with this resistor array on the inlet side of the heating resistor array for the thermal paper or thermal ink ribbon that is fed to the thermal head, it can function as a preheating source. arise.

Furthermore, in the present invention, a resistor film is formed on one surface of a flexible insulating substrate made of a heat-resistant organic film by vapor deposition or sputtering, and after a lead material is laminated on this film, a pattern of heat generating resistor arrays is formed. A step of attaching a resistor film to the other surface of the flexible insulating substrate and placing a second band-shaped heating resistor corresponding to the pattern of the heating resistor row immediately below the heating resistor row. A thermal head characterized in that it comprises the steps of: forming a substrate at an adjacent position; and bonding a surface of the obtained flexible insulating substrate on the side of the second heating resistor to a support. It's in the manufacturing method.

[Embodiments of the invention]

1 to 3 show a first embodiment of the present invention.

First, in FIG. 1, a heat-resistant organic film such as a polyimide film (11) is used as a flexible insulating substrate. A thin film resistor film (12) is attached to one surface thereof. The resistive film material is required to be resistant to high-speed thermal stress, and for example, a Ta-8in□ sputtered film is suitable.

The second lead material (13) is C.
r/Au/Ti etc. are laminated and deposited by vacuum evaporation or the like. Forming a pattern according to a desired resolution such as 8 lines/m, 16 lines/meter, etc. using microfabrication technology such as photoetching,
After completing the formation of the heating resistor array (14) as shown in Fig. 2, a wear-resistant protective film (
15) Attach.

Next, on the other surface of the polyimide film (11),
A resistive film is attached and etched to form a band-shaped heating resistor (1 (: )).

The length is the same length as the previous Ali heating resistor row (5), and the heating resistor row (14) is formed parallel to the d[i recorder 11 side. Reed electrodes (17) are provided at both ends of the resistive film, and the parts except for the lead-out portions are insulated by coating with insulating resin (18) or the like.

Next, as shown in Figure 3, a metal with good thermal conductivity such as A
An insulating substrate is glued to the heat dissipation plate (2 (4)) consisting of the polyimide substrate.
During etching, the lead wiring (13
a), and according to its wiring pattern, drive IC (1
:l) and the wire bonding (22) connection is made. A cover (23) is placed over them to protect them.

4 and 5 show a second embodiment of the invention. Here, parts with the same reference numerals as in FIG. 1 indicate similar parts.

FIG. 4 shows a sectional view of the thermal head in an intermediate step. First, a metal substrate (1o) is prepared. The material is selected from among those that have good thermal conductivity, are resistant to deformation even when thin, have opposite properties to polyimide with respect to etching solutions, and can be obtained at low cost. In the example, Fe was used. The thickness was selected so that it could be easily removed by etching later and the thickness would not cause deformation as a flat substrate.
5 to 1.0+n+a is good. In the example, 0, I m
m t;

C and r are deposited in a thin layer of about 500 to 1000 on the surface of an Fe substrate of 0.0,1 mut by vacuum evaporation or the like. This acts to strengthen the adhesion between the flexible insulating substrate (11) of the polyimide film attached to the -1- and the metal substrate (1 (4)).As the heat-resistant organic material, polyimide resin UPIIIEX-3 (trade name manufactured by Ube Industries) was used.This resin has a thermal decomposition onset temperature of 6.
00℃, which is excellent.

This varnish-like material was applied to the Fe substrate (1(4)l-
For example, by applying it to -1- of the Cr film using a spinner method,
By holding the step 4 temperature at 100° C. and 250° C. for several tens of minutes and finally heating it to 450° (:), complete imidization occurs and an organic film with excellent heat resistance is formed.

In the example, a uniform film of 20 μm was obtained.

By exposing the surface of this polyimide film to plasma discharge in an oxygen atmosphere and performing fine surface etching, the surface area becomes larger and the adhesion of the next film to be applied becomes stronger. A resistive film is attached to the surface of the polyimide flexible insulating substrate (11) that has been pretreated in this way. This is, for example, a Ta-3in□ sputtering film.

Hereinafter, the wear-resistant protective film (15
) to finish adhesion. Next, the Fe material at the position (25) is removed by photo-etching the Fe substrate on the back side. The combination of materials in this example is advantageous because while the Fe is etched with ferric chloride, the polyimide is hardly etched. After Fe is removed, a resistive material is formed in the form of a film on the exposed back surface of the polyimide. As described above, this can also be deposited by RF sputtering or the like. Polyimide substrate (11)
This means that a resistive film (16) is formed on the back surface of the polyimide insulating substrate, close to and parallel to the heating resistor array (14) formed on the surface of the polyimide insulating substrate and having the same length as the beam. The resistor (16) is completed by adhering the lead layer (17) by vacuum evaporation or the like and photoetching, and the resistor (16) is completed by covering the parts other than the lead-out electrode with an insulating protective film (18).

In Figure 5, a heat sink (
26) is prepared, and a heating resistor array (
14) and the strip resistor (16) on the back surface, and the lead wire (13) of the heating resistor row (14) is placed on the main plane adjacent to the end surface.
The completed substrate is bonded so that the wires extend through the substrate 1.

At this time, the part where the Fe material on the back side was etched away (25
) is supported only by a polyimide substrate and is flexible and elastic, and by bending smoothly, the leads (13) can be guided to the plate surface without lead breakage.

The following conflicts occur on the surface of the metal heat sink (26). Driver circuit board prepared in advance (2
8), and a driving IC (29) is adhesively fixed to that predetermined location. The driver circuit board (28) with the IC (29) attached is adhesively fixed to the surface of the heat sink (26).

The lead terminal (13a) of the board (11) and the drive! 11 I
C (29), drive TC (29) and driver circuit board (2
8) Wire bonding between the extraction terminals (3 and 4)
31) etc., and attach the protective cover (32) to complete the process.

According to the thermal head of this embodiment, the metal heat sink (26
) Since the heating resistor array (14) is provided on the end face (27), the thermal paper (33) is placed on the platen (
34) to make good thermal contact, and the thermal signal from the heating resistor array (14) can be efficiently transmitted to the thermal paper (33). Moreover, since the second heating resistor (16) is arranged on the end surface (27), on the 1-1 thermal paper feed/input I+ (35) side, this heat generation reaches the heating resistor row (14). The temperature of the previous thermal paper (33) is raised to a temperature higher than the heat-sensitive level, that is, the color development level. That is, it acts as a preheat source. Flexible insulation board made of organic film (12)
If there is a large temperature difference between the heat-generating resistor array when it is not generating heat and when it is generating heat, the heat resistance is likely to deteriorate and the resistors may peel off. However, by preheating the thermal paper from the back surface of the substrate by the second heating resistor (1G) in this embodiment, the thermal energy of the heating resistor array can be significantly alleviated, so that the heat resistance of the organic resin substrate is improved. It becomes possible to manufacture a thermal head that is not damaged and has a long life. It is also effective for recording when the ambient temperature is low.

A third embodiment of the present invention will be described with reference to FIG. The middle part up to -r is completely the same as the second embodiment, so the explanation will be omitted. Note that parts with the same reference numerals indicate similar parts.

The main difference between this embodiment and the second embodiment lies in the shape of the heat sink (36).

The end face of the heat dissipating plate (36) made of a metal with good thermal conductivity and the corner of the boundary between the board surfaces connected to the end face are cut to form a slope (37), and a row of heating resistors (14) and a slope (37) are formed on the slope. The second heat generating resistor (16) on the back surface is adhesively fixed so as to be placed thereon. Since the heat generating portion is attached to the slope l2, the thermal head can be incorporated into a narrow space of the recording apparatus, and the apparatus can be made smaller.

〔Effect of the invention〕

The effects of the present invention are as follows.

(2) The recording paper and its surroundings can be warmed in advance.

2) The peak temperature of the heating resistor array can be lowered.

:3) The life of the heating resistor array can be extended.

4) Good recording quality can be obtained without being affected by ambient temperature.

5) Since the peak temperature of the main heating resistor can be kept low, an organic resin can be used as a base for the heating element.

6) Therefore, it is easy to form a vertical or inclined thermal head, especially a non-planar thermal head.

7) Therefore, the recording device can be made smaller.

8) Manufacture by photoetching becomes easy, and 16 pieces/
Vertical high-definition thermal heads such as I are possible.

[Brief explanation of the drawing]

1 to 3 are schematic diagrams showing a first embodiment of the present invention, FIGS. 4 to 5 are schematic diagrams showing a second embodiment of the present invention, and FIG. 6 is a schematic diagram showing a second embodiment of the present invention. FIG. 5 is a simplified explanatory diagram for explaining the effects of the second embodiment of the present invention, and FIG. 7 is a schematic diagram showing the third embodiment of the present invention. (11)...Flexible insulating substrate, (13)...Lead, (+3a)...Lead wiring, (14)...Heating resistor array, (15)...Wear-resistant protective film , (16)
...heating resistor. (18)...Insulating protective film. Agent: Patent attorney Kensuke Chika (and 1 other person)

Claims (7)

[Claims] (1) A flexible insulating substrate made of a heat-resistant organic film, a heating resistor array formed on the surface of the flexible insulating substrate, and a lead extending from the heating resistor array onto the flexible insulating substrate. and a support for supporting the flexible insulating substrate, wherein the flexible insulating substrate has a heating resistor array on a surface opposite to the surface on which the heating resistor array is formed. A thermal head characterized in that a second heat generating resistor having a length corresponding to the heat generating low antibody array is formed at a position shifted from the corresponding position. (2) The thermal head according to claim 1, wherein the second heating resistor is integrally formed in a band shape. (3) The second heating resistor on the flexible insulating substrate is arranged on the inlet side of the fed thermosensitive recording medium to preheat the thermosensitive recording medium. thermal head (4) The thermal head according to claim 1, wherein the support is a good thermal conductor. (5) The thermal head according to claim 4, wherein the support is an end face of a metal plate, and the flexible insulating substrate and the second heating resistor are arranged in parallel on the end face. (6) The thermal head according to claim 5, wherein the end surface of the metal plate is sloped with respect to the plate surface, and a flexible insulating substrate is adhered to the sloped end surface. (7) A step of forming a resistor film on one surface of a flexible insulating substrate made of a heat-resistant organic film by vapor deposition or sputtering, laminating a lead material on this film, and then forming a pattern of heat-generating resistor arrays. and a resistor film is attached to the other surface of the flexible insulating substrate, and a band-shaped second heating resistor corresponding to the pattern of the heating resistor row is attached except for the part immediately below the heating resistor row.
A method for manufacturing a thermal head, comprising the steps of: forming the substrate at an adjacent position; and bonding the surface of the obtained flexible insulating substrate on the side of the second heating resistor to a support.