JP2529320Y2 - Thermal head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a thermal head, and more particularly, to a structure of a head cover provided on the thermal head.

[Prior Art] FIG. 5 is a cross-sectional view showing a configuration example of a typical thermal head 1. The thermal head 1 has a heat radiating plate 2 on which a head substrate 3 is fixed. On the head substrate 3,
A large number of heating elements 4 are formed in a straight line in a direction perpendicular to the paper surface of FIG. 5, and a plurality of driving circuit elements 5 electrically connected to the heating elements 4 to perform heating driving are arranged in parallel with the heating elements 4. Provided. The drive circuit element 5 is connected to the flexible connection substrate 6 by a connection electrode (not shown) extending on the side opposite to the heating element 4. The flexible connection board 6 is provided with the heat sink 2
It is mounted on a reinforcing member 7 above.

The drive circuit element 5 is covered with a protective layer 8 made of a synthetic resin material. Further, a head cover 9 made of a synthetic resin material is attached from the protective layer 8 to the flexible connection substrate 6. A connection leg 10 is provided on the head cover 9, and a cracked lock piece 11 is formed at the tip of the connection leg 10. The connection leg 10 passes through the flexible connection board 6, the reinforcing member 7, and a through hole (not shown) formed in the heat sink 2, and penetrates to the opposite side of the heat sink 2. The head cover 9 is fixed to the heat radiating plate 2 by a lock piece 11.

By using the thermal head 1, for example, the thermal paper 13 wound around the platen roller 12 is rotated in the direction of arrow A1 in FIG. 5, and the heating element 4 is driven to generate heat to perform thermal printing. At this time, the head cover 9 prevents the thermal paper 13 from colliding or excessively abutting against the protective layer 8 to prevent abrasion, guides the thermal paper 13, and allows the flexible connection substrate 6
It has the function of covering and protecting.

[Problem to be Solved by the Invention] In the above-described conventional example, the layer thickness d1 of the flexible connection substrate 6, the height h1 of the protective layer 8, the layer thickness d2 of the head substrate 3, and the connection leg 10 of the head cover 9 are used. The gap 14 between the head cover 9 and the protective layer 8 due to variations in processing accuracy such as length.
The thermal paper 13 or the like easily enters the gap 14 to easily cause a paper jam. In addition, since the head cover 9 is large because the flexible connection substrate 6 is entirely covered, there is a problem that the miniaturization of the thermal head 1 is hindered and the cost is increased.

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermal head which can solve the above-mentioned technical problems, improve the operational reliability, and reduce the size of the configuration.

Means for Solving the Problems The present invention has a plurality of heating elements arranged linearly on an upper surface of a substrate, a plurality of driving circuit elements arranged in parallel with an arrangement direction of the heating elements, A thermal head comprising a drive circuit element and a resin layer covering the drive circuit element, wherein a metal foil is adhered to an upper surface of a substrate from at least a region of the resin layer facing the heating element, and the metal foil is grounded. It is.

[Operation] In the thermal head of the present invention, a plurality of heating elements are arranged linearly on a substrate, and a plurality of drive circuit elements are arranged in parallel with the arrangement direction of the heating elements. This drive circuit element row is covered with a resin layer. A metal foil is adhered onto the substrate from at least a region of the resin layer facing the heating element, and the metal foil is grounded. This prevents a gap from being formed between the metal foil and the substrate, and prevents a situation in which thermal paper or the like enters such a gap to cause a paper jam. Generation of static electricity can be prevented. Further, the metal foil only needs to be large enough to cover at least a region of the resin layer facing the heating element, and can contribute to miniaturization of the thermal head.

FIG. 1 is a cross-sectional view illustrating a basic configuration of a thermal head 21 according to an embodiment of the present invention. The thermal head 21
Radiator plate 22 made of a metal material such as aluminum
The head substrate 23 is fixed thereon with an adhesive layer 33 (see FIG. 2). A large number of heating elements 24 are linearly formed on the head substrate 23 in a direction perpendicular to the paper surface of FIG. 1, and are arranged in parallel with the arrangement direction of the heating elements 24. And a plurality of drive circuit elements 25 connected to each other. These drive circuit elements 25 are covered with a protective layer 26 made of a synthetic resin material.

Head substrate 23 on the opposite side of heating element 24 of drive circuit element 25
On the upper side, a reinforcing member 27 made of a synthetic resin is provided. A metal foil tape (hereinafter, abbreviated to tape) 28 as a belt-like body is attached to a region including a range from the surface of the protective layer 26 facing the heating element 24 to the reinforcing member 27. The tape 28 is composed of an adhesive layer 29 and a metal foil 30 of, for example, aluminum or stainless steel, and is adhered by the adhesive layer 29. The metal foil 30 is connected to a ground circuit of the substrate 23. Such a thermal head 21 includes a platen roller 31
The heat-sensitive paper 32 wound around the heater slides on the heat-generating element 24, and heat-sensitive printing is performed.

FIG. 2 is a sectional view for explaining the configuration of the thermal head 21 in detail, and FIG. 3 is a plan view of the thermal head 21. The configuration of the thermal head 21 will be described in detail with reference to these drawings. On the head substrate 23, a heat storage layer 35 is formed by a thick film technique such as screen printing, and a thick film common electrode layer 45 is formed along the outer periphery of the head substrate 23.

On the heat storage layer 35, a heating resistor layer 34, a common electrode layer 36, and a plurality of individual electrodes 37 are formed.
24 are configured. The heating element 24 performs thermal printing on the thermal paper 32 with the platen roller 31 via a wear-resistant layer 39 made of, for example, ceramic or the like. The heating element 24 is controlled by a drive circuit element 25 realized as an integrated circuit element. The drive circuit element 25 is connected to the individual electrodes 37 covered with the insulating layer 44, and inputs a signal for driving the heating element 24 to the drive circuit element 25, and external connection terminals covered with the insulating layer 44. 43 is connected, and a protective layer 26 made of a synthetic resin material or the like is formed to cover the drive circuit element 25 and its periphery.

The procedure for forming the thermal head 21 is as follows. That is, after the heat storage layer 35 is formed on the head substrate 23, the thick film common electrode layer 45 and the common electrode connection lead wires (hereinafter abbreviated as connection lead wires) are formed along the outer periphery of the head substrate 23 by the thick film technology. 46 is formed integrally with the head substrate 23 over the entire length in the left-right direction in FIG. A common ground electrode connecting lead wire (hereinafter abbreviated as connecting lead wire) 47 is formed at a distance from the connecting lead wire 46 over the entire length of the head substrate 23 in the left-right direction. The insulating layers 49, 50, and 51 are integrally formed at the positions corresponding to the connection lead wires 46 and 47, the common ground electrode 52, and the external connection terminal 43 at the same step as the insulating layer 48 using the same material as the heating resistor layer 34. Formed.

On the head substrate 23, the common electrode layer 36 made of a metal plating layer that covers the entire surface of the thick film common electrode layer 45 is formed. Insulation layer in parallel with this common electrode layer 36
On the lower layer side of each drive circuit element 25 on 50, the head substrate
23, extending over the entire length in the left-right direction of FIG.
The common ground electrode 52 serving as 25 common ground electrodes is formed.

The common ground electrode 52 and the connection lead wire 47 are connected by connecting pieces 53 between adjacent drive circuit elements 25, respectively. The right end in FIG. 3 of the connection lead wire 47 extends to the vicinity of the left end in FIG. 3 along the lower end in FIG. On the other hand, the common ground electrode 52
The left end of FIG. 3 is drawn out to the lower end of FIG. 3 of the head substrate 23 to serve as a common electrode external connection terminal (hereinafter abbreviated as an external connection terminal) 54. The left end of the common electrode layer 36 in FIG. 3 is drawn out to the lower end of FIG. 3 of the head substrate 23 to serve as a common electrode external connection terminal (hereinafter abbreviated as an external connection terminal) 55.

The protective layer 26 is formed over a range including the drive circuit element 25 shown in FIG. Further, on the insulating layer 44 corresponding to the lower area of the drive circuit element 25 in FIG. 2, that is, the insulating layer 44 corresponding to the installation area of the connection lead wire 47 and the external connection terminal 43, for example, a rectangular column-shaped reinforcing member 27 made of synthetic resin material is provided. Fixed. The tape 28 is adhered by covering the protective layer from the insulating layer 44 in the region of the protective layer 26 facing the thermoelectric element 24 to the reinforcing member 27.

Such a tape 28 covers the protective layer 26 in close contact, so that no gap is formed between the tape 28 and the protective layer 26, so that the thermal paper 32 or the like enters the gap and causes paper jam. The situation can be prevented. The tape 28 has a protective layer 26
In addition, since only the vicinity of the external connection terminal 43 involved in the connection between the head substrate 23 and the external connection substrate 65 is covered, the configuration can be significantly reduced as compared with the conventional head cover 9 shown in FIG. For this reason, it can greatly contribute to downsizing of the thermal head 1. Also, since the metal layer 30 is arranged facing the thermal paper 32, the tape 28 is
A situation where static electricity is generated even when contact is made can be prevented.
In addition, since the metal layer 30 of the tape 28 is connected to the ground circuit of the head substrate 23, even if static electricity flows into the tape 28, the static electricity does not accumulate in the tape, and it is possible to prevent a failure due to static electricity. .

FIG. 4 is a sectional view of a thermal head 21a according to another embodiment of the present invention. This embodiment is similar to the previous embodiment, and corresponding parts are denoted by the same reference numerals. The thermal head 21a of the present embodiment is a conventional thermal head 1 shown in FIG.
In this configuration, the head cover 9 and the configuration accompanying the head cover 9 are omitted, and the reinforcing member 27 is disposed on a connection portion between the head substrate 23 and the external connection substrate 65 mounted on the heat sink 22 via the reinforcing member 27. It is. The above-mentioned tape 28 is adhered by covering the protective layer 26 from the reinforcing member 27. Also in such an embodiment, the head cover 9 described in the conventional example of FIG. 5 can be omitted, and the same effect as that described in the above-described embodiment can be achieved.

In the above-described embodiment, the metal layer 30 of the tape 28 is described as aluminum or stainless steel. Do not ask. Further, the tape 28 may be formed of a synthetic resin material instead of the metal layer 30. Even such a tape can greatly contribute to miniaturization of the configuration of the thermal head 21.

[Effects of the Invention] As described above, according to the present invention, the drive circuit element row is covered with the resin layer, and a metal foil is adhered onto the substrate from at least a region of the resin layer facing the heating element. Grounded. This prevents a gap from being formed between the metal foil and the substrate, prevents a situation in which thermal paper or the like enters such a gap and causes a paper jam, and prevents the thermal paper from contacting the metal foil. This can also prevent the occurrence of static electricity. Further, the band-shaped body may have a size that covers at least a range including the surface of the resin layer on the side facing the heating element, and can contribute to miniaturization of the thermal head.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a thermal head 21 according to an embodiment of the present invention, FIG. 2 is a sectional view of the thermal head 21, and FIG.
FIG. 4 is a plan view of the thermal head 21, FIG. 4 is a sectional view of a thermal head 21a according to another embodiment of the present invention, and FIG. 5 is a sectional view of a typical conventional thermal head 1. 21,21a …… Thermal head, 23 …… Head substrate, 24 ……
Heating element, 25 ... Drive circuit element, 26 ... Protective layer, 27 ...
Reinforcing member, 28 Tape, 32 Thermal paper

Claims (1)

(57) [Scope of request for utility model registration] 1. A plurality of heating elements arranged linearly on a top surface of a substrate, a plurality of driving circuit elements arranged in parallel with an arrangement direction of the heating elements, and a resin layer covering the driving circuit elements. A thermal head, comprising: bonding a metal foil to an upper surface of a substrate from at least a region of the resin layer facing a heating element, and grounding the metal foil.