JPH02206559A - Printing head - Google Patents

Abstract

PURPOSE:To increase the number of recording electrodes and thereby provide clear print by applying insulating coat around the recording electrode of extremely fine wire obtained by drawing a metal material and arranging these electrodes as the cord is allowed to come in contact with such other. CONSTITUTION:A recording electrode 15 consists of a tip section of extremely fine wire 12A obtained by drawing a metal material, e.g. tungsten. The electrode 15 has an insulating coat 16 applied around it. About 40 to 100 pieces of the recording electrode 15 are aligned in an array as in contact with each other. Then an insulating resin used for forming a substrate 17 for a printing head is poured to fix these recording electrodes 15, and these are integrated with the substrate 17 as a one-piece body. Thus a clear print can be provided by increasing the number of the recording electrodes. In addition, the recording electrode is physically strengthened due to its increased plasticity. Subsequently, it becomes more abrasion-resistant.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a print head, and more particularly to an electric thermal print head used in word processors and the like.

(Prior Art) A current-carrying thermal printhead is used as a writing multi-electrode head for a recording device such as a word processor that records an electrical signal as a visible image.

This thermal print head is superior in that it can print beautifully and at high speed regardless of the material of the recording paper. FIG. 4 shows the middle column principle of this current-carrying thermal printhead.

A transfer ink ribbon 3 is interposed between an electric thermal print head 1 and a recording paper 2. This transfer ink ribbon 3
is a conductive layer 3 between a resistive base 3A and an ink layer 3B.
It is composed of C. When electricity is applied between the print head 1 and the transfer ink ribbon 3, the ink layer 3B of the transfer ink ribbon 3 is transferred onto the recording paper 2 due to the concentrated heat (Joule heat 7). and printed. In FIG. 3, reference numeral 4 indicates a switching circuit, reference numeral 5 indicates transferred ink, and reference numeral 6 indicates a return electrode.

The print head 1 is constructed by arranging a large number of recording electrodes (not shown) in one row. For example, if the width of the print head 1 is approximately 4jIII, 40 recording electrodes are arranged in the width direction of the print head 1.

Therefore, since the interval between the recording electrodes is small, the print head 1 is manufactured by forming a vapor deposited film on the printed circuit board by vapor deposition, and then forming the recording electrodes by etching.

(Problem to be Solved by the Invention) However, when the recording electrode is formed by the vapor deposition method as described above, the vapor deposited film is relatively porous and has low strength, so it may be damaged by friction with the transfer ink ribbon 3. There is a risk that the recording electrode will wear out. Due to this wear,
If a gap is created between the recording electrodes of the print head 1 and the transfer ink ribbon 3, arcs are likely to occur between these recording electrodes and the ribbon 3. Then, due to this arc, the recording electrode of the print head 1 is oxidized and oxides are generated, which may deteriorate the conductivity of the recording electrode and make printing unclear.

Additionally, there is a demand for increasing the number of recording electrodes arranged in the print head 1 in order to improve the clarity of printing. For example, there is a demand for arranging 56 or 80 recording electrodes in the width direction of a print head 1 having a width of 4 sub-widths. However, in order to meet these demands, when manufacturing the print head 1 using conventional vapor deposition and etching methods, the interval between recording electrodes becomes extremely small, resulting in non-uniform cross-sectional areas of each recording electrode, and The film thickness between the electrodes also becomes non-uniform. For this reason, the number of recording electrodes cannot be increased, and as a result, the clarity of printing cannot be improved.

Furthermore, when manufacturing a print head by the above-mentioned vapor deposition and etching method, the cross-sectional area of each recording electrode is made uniform, and the thickness of the vapor-deposited film is also appropriately adjusted to 1IlIJ.
Since it is necessary to carry out tll, manufacturing becomes complicated and manufacturing cost increases.

This invention was made in consideration of the above-mentioned circumstances, and it is possible to increase the number of recording electrodes to improve printing quality, and to provide a print that has high strength, high wear resistance, and is easy to manufacture. The purpose is to provide the head.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a print head in which a large number of recording electrodes are arranged in the width direction of the head and each recording electrode is insulated from each other, in which the recording 144 is formed by drawing a metal material. It is characterized in that it is constructed as a wire rod with an extremely thin diameter, and an insulating coat is applied around each of the recording electrodes, and a large number of the recording electrodes are arranged with the insulating coats in contact with each other. It is.

(Function) Therefore, according to the print head according to the present invention,
Since the recording electrode was formed from a wire drawn, it has a high density, and since the crystal grains extend in the length direction of the wire, it has high strength. Therefore, the recording electrode has high wear resistance, and wear caused by contact with the transfer ink ribbon can be reduced.

Furthermore, since the recording electrode is formed from a wire rod by drawing, it is possible to form a recording electrode with an extremely small diameter while making the wire diameter uniform. Therefore, the number of recording electrodes arranged in the print head can be increased, and as a result, the clarity of printing can be improved.

Furthermore, by arranging the recording electrodes with insulating coats in contact with each other, the pitch between each recording electrode becomes constant, making it easier to manufacture the print head compared to vapor deposition and etching methods.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a plan view showing a print head unit 1- to which an embodiment of the print head according to the present invention is applied.

The print head unit 11 includes a print head 12, a flexible coupling part 13, and a connector 14. Further, the print head 12 is provided with a recording electrode 15, an insulating coat 16, and a head substrate 17, as shown in FIG.

The recording electrode 15 is constructed as a tip portion of a wire rod 12A having an extremely small diameter by plastically working a scrap metal material, such as tungsten (hereinafter abbreviated as W) material after electric discharge machining, by wire drawing. The thread diameter of each recording electrode 15 is about 5 to about 50 microns. Further, an insulating coat 16 is applied around the recording electrode 15 .

The procedure is to first apply A to the surface of the recording electrode 15 if necessary.
A low melting point metal such as LJ (gold) or Ni (nickel) is plated, and then a resin coating is applied around the plated recording electrode 15 to form an insulating coat 16.

A suitable material for the insulating coat 16 is polyimide or polyurethane varnish. The thickness of the insulation core 1 to 16 is about 5 to about 20 μm.

The plating process is performed before resin coating of the insulating coat 16 because W, which is the material of the recording electrode 15, is difficult to adhere to resin, and also to improve the conductivity of the W recording electrode 15. . The thickness of this plating is suitably about 0.1 to about 1.0 μm.

About 40 to about 100 recording electrodes 15 are arranged in a row with their insulating coats 16 in contact with each other. In this state, an insulating resin constituting the head substrate 17 is poured to harden these recording electrodes 15 and integrate them with the head substrate 17. As shown in FIG. 1, the width of the head end portion 18 of the head substrate 17 is typically 4JIII,
About 40 to about 100 recording electrodes 15 with insulating coats 16 are arranged in a row in the width direction of the head end of the fin. Here, the insulating resin that is the material of the head substrate 17 needs to have insulating properties and a certain degree of strength, so glass epoxy resin, ceramic, or the like is suitable, for example.

On the other hand, the flexible connecting part 13 has a tip end connected to the recording electrode 1.
Similarly to the recording electrodes of the print head 12, W wire rods 12A having an ultra-thin diameter and functioning as 5 are arranged in a row and hardened with flexible resin or the like.

This flexible connecting portion 13 is joined to the head substrate 17 of the print head 12 via an adhesive portion 19 . Further, the end portion of each wire 12A is connected to the connector 14.

As shown in FIG. 3, this connector 14 is formed by attaching a conductor 21 onto a printed circuit board 20 by chemical means such as etching.
was formed. The number of conductors 21 is equal to the number of recording electrodes 1
The number is the same as 5. The ends of each wire 12A of the flexible connecting portion 13 are fixed to the conductor 21 by soldering or the like.

The conductor 21 is also configured to be connectable to the switching circuit 4 shown in FIG. 4, and allows current to flow through the flexible connection 13 to each recording electrode 15 of the print head 72.

According to the above embodiment, the recording electrode 1 of the print head 12
Since the wire rod 12A is formed by drawing a W material, the wire rod 5 has a high density, and the W crystal grains roughly extend in the length direction of the wire rod 12A, so that the strength is increased. Therefore, the abrasion resistance of the recording electrode 15 is improved, and the abrasion of the recording electrode 15 can be reduced even by contact with the transfer ink ribbon 3 (see FIG. 4).

Further, since the recording electrode 15 of the print head 12 is constituted by the wire 12A formed by drawing a W material, the recording electrode 15 can have an extremely small diameter of about 5 to about 50 μm. Therefore, the number of recording electrodes 15 arranged at the head end 18 can be increased to about 40 to about 100. Moreover, according to the wire drawing process, the wire diameter of each wire rod 12A can also be made uniform. Furthermore, since the wire rod 12A is formed by plastic working by wire drawing, arc characteristics are improved. An increase in the number of these recording electrodes 15,
By making the diameter 1a of the wire rod 12A uniform and having good arc characteristics, the clarity of printing can be improved.

In particular, since the wire 12A is made of W, the abrasion resistance of the recording electrode 15 is good, and the corrosion resistance of the ink 13B (see FIG. 4) in the transfer ink ribbon 3 is also good. Furthermore, since the wire rod 12A is made of W, it is possible to draw the wire to a uniform diameter down to an extremely fine diameter, and since oxides are less likely to be generated on the recording electrode 15, arc characteristics are also improved.

As a result of uniform wire diameter and good arc characteristics, the clarity of printing is better than with other materials.

Further, since the surface of each recording electrode 15 is coated with an insulating coat 16, insulation between each recording electrode 15 is ensured. At the same time, when manufacturing the print head 12, the recording electrodes 15 coated with the insulating coats 16 may be arranged with the insulating coats 16 in contact with each other, and then solidified by the head substrate 17. Therefore, simply by bringing the insulating coats 16 into contact with each other, the pitch P (see FIG. 2) between the recording electrodes 15 can be made uniform, contributing to improving the clarity of printing.

As a result, the print head 12 can be manufactured more easily than by conventional vapor deposition and etching methods.

Furthermore, since the connector 14 connected to the switching circuit 4 (see FIG. 4) and the print head 12 are connected by the flexible connection part 13, the connector 14 can be used as a fixed side and the print head 12 can be used as a movable side. can. Therefore, the moving side can be downsized, and the recording apparatus as a whole can be downsized.

In the above embodiment, the wire rod 12A was made of W, but the wire rod 12A was made of Fe (iron).
, Ni), Cu (copper), or Mo (molybdenum).

〔Effect of the invention〕

As described above, according to the print head according to the present invention,
The recording electrode is formed by drawing a metal material into a wire with an extremely small diameter, an insulating coat is applied around each of the recording electrodes, and a large number of the recording electrodes are arranged with the insulating coats in contact with each other. Because of this structure, the number of recording electrodes can be increased, so printing quality can be improved.

At the same time, since the recording electrode is formed by wire drawing as plastic working, the strength of the recording electrode can be increased and the wear resistance can also be improved. Furthermore, since the print head is constructed by arranging the recording electrodes with their insulating coats in contact with each other, manufacturing is facilitated.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a print head unit to which an embodiment of the print head according to the present invention is applied, FIG. 2 is a view taken along line 11 in FIG. 1, and FIG. FIG. 4, an enlarged plan view of the connector, is a conceptual diagram showing the principle of printing by a conductive thermal print head to which the present invention is applied. 12...Print head, 12A...Wire rod, 15.
... Recording electrode, 16... Insulating coat, 17... Head substrate, 18... Head end. Figure 3: Applicant's agent Hisashi Hatano Figure 4

Claims (1)

[Claims] In a print head in which a large number of recording electrodes are arranged in the width direction of the head, and each recording electrode is insulated from each other,
The recording electrodes are formed by drawing a metal material into a wire rod with an extremely small diameter, and an insulating coat is applied around each of the recording electrodes, and a large number of the recording electrodes are arranged with the insulating coats in contact with each other. A print head comprising: