JPH0784060B2 - Wire-type impact dot head - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a drive device for a wire type impact dot head.

<Prior Art> Normally, the wire type impact dot head defines the distance between the tip of the wire and the platen (hereinafter referred to as the platen gear A) and the thickness of the paper to be printed. In other words, a mechanism for adjusting the platen gear is provided in the carriage and its components so that the head is mounted so that the platen gear on the narrow side can be used for thin paper and the platen gear on the wide side can be used for thick paper such as copy paper. . The impact dot head is normally driven within the specified range to perform printing, but when actually used by the user, the printer is not always used after adjusting to the designated platen gear. It is possible to print thick paper with a narrow platen gear tape or thin paper with a wide platen gear tape. In the former case, the ink ribbon causes paper stains when the printing paper is loaded, and the user adjusts the platen gear, but in the latter case, it is highly likely that the user does not notice until printing. Even under such printing conditions outside the expected range of use, no troubles that may lead to destruction should occur.

The impact dot head generally has a core portion 3b.
It is composed of an armature having a frame 3 having the above, a yoke 4 and a wire 1 arranged at the tip. In the standby state, the armature 2 is applied to the rear damper rubber 10 by the reset spring 6. The distance (hereinafter referred to as wire stroke) from that state to the contact with the surface 3a of the coil core is adjusted to be uniform. When driving within the normal specification range, the platen gear cut is used at a distance smaller than the wire stroke, but in the latter specification state outside the above-mentioned specification range, the platen gear cut is likely to have a wire stroke or more.

Conventionally, there is no inclusion between the armature 2 and the core part 3b, and when the platen gear is longer than the wire stroke, the armature 2 and the core surface 3a come into contact with each other and the air gear gap between the armature 2 and the core surface 3a disappears and remains. The effect of the magnet slows the recovery of the armature. Fig. 2 shows the behavior of the wire. The behavior of A in the figure is that when it is used within the specification range, and it is the behavior when the waveform of c is the conventional head and the platen gear is over the wire stroke. . The waveform of c is greatly affected by the residual magnetic flux because the armature is in contact with the core and the air gear gap disappears, and the return of the wire after impact on the core is smooth and slow as shown in the figure. If this operation continues, the wire will continuously protrude from the head of the head as shown in Fig. 3A, and the wire will be caught by the ink ribbon that moves laterally along the head of the head, not only destroying the ink ribbon but also in the worst case. It develops into a phenomenon that the wire breaks.

In addition, there are some conventional frames with a metal plate, but the purpose is only to prevent rust and the thickness of the metal plate is 5μ.
It is given below. The thickness of this plating cannot prevent the influence of the residual magnetic flux as described above.

In other conventional technologies, a spacer for setting the air gear made of a non-magnetic material was inserted between the armature core, but the durability is poor and the life cannot be extended.

2. Accurate air gears cannot be secured due to burrs, sledges and burrs.

3. If the thickness is thick, the spacer is a very expensive part because a thin micron-scale material is used to reduce the magnetic properties.

There is a problem such as.

As described above, the conventional structure has a problem that when the platen gear is longer than the lever stroke, the ribbon is hooked and the ribbon material is damaged and the wire is broken.

<Problems to be Solved by the Invention> In the prior art, when the platen gear is longer than the wire stroke, there is no air gear between the armature and the core. The wire constantly protrudes from the tip of the head, catches the ink ribbon, breaks the ribbon material, or breaks the wire. It is also possible to insert a spacer in order to forcibly secure the air gear gap between the armature core and the core, but the durability is poor and it is not possible to secure an accurate air gear gap due to burrs, sleds and burrs. In addition, there is a problem that the cost is high because a material of micron unit is used.

Therefore, the present invention provides a head that secures an air gear gap between the armature and the core without deteriorating the magnetic characteristics and using an expensive spacer, and does not cause ribbon hooking or wire breakage even when the platen gear cup has a wire stroke or more. The purpose is to do.

<Means for Solving Problems> That is, according to the present invention, as a wire type impact dot head for solving the above problems, the suction surface of the core for sucking the armature does not exceed 200 ° C. The electrolytic nickel plating layer is formed by coating.

<Example> An example of the present invention will be described below.

FIG. 1 shows an embodiment of the present invention.

In the figure, reference numeral 3b is a core formed together with the frame 3 using a magnetic material such as 3% silicon steel or 1% silicon steel. By energizing the coil 5 wound around the core 3b, the frame 3 and the yoke 4 At the same time, the armature 2 constituting the magnetic circuit is attracted to the surface 3a of the core 3b, and the wire 1 fixed to the tip is projected to the tip of the head to print on the recording paper 8.

In the figure, reference numeral 6 is a reset spring for returning the armature 2, 10 is a rubber for a damper, and 7 is an ink ribbon.

By the way, reference numeral 3d in the drawing denotes an electroless nickel plating layer which coats and forms the surface 3a of the core 3b together with the entire surface of the frame 3, within a range that does not exhibit magnetism, that is, 200 ° C or less even when heat treatment When the armature is adsorbed by coating the surface 3a of the core 3b with the electroless nickel plating layer 3d with a thickness of 20 to 40 μm at the temperature of
This electroless nickel plating layer 3d which does not exhibit magnetism forms a gap equivalent to an air gap between the attraction surface 3a of the core 3b and the armature 2 so as to bring about the following effects. . That is, 1. Normally, nickel becomes a magnetic material in a crystalline state,
The plating layer formed by electroless nickel plating becomes amorphous and exhibits non-magnetic properties. In the present invention, since the electroless nickel plating layer is applied to the frame, the air gear layer is formed. 300-400 ℃ after Taseki-Mesh treatment
When the heat treatment is applied, it changes from amorphous to crystalline and exhibits magnetism.
Do the following:

2. Unlike electroless plating, electroless nickel plating provides a uniform thickness layer that does not depend on the shape of the object to be plated, and it is possible to keep the variation within 10% of the thickness of the plating.

Therefore, if the dimensional accuracy of the frame before the plating is taken out, the accuracy is maintained even after the plating, and the accurate dimensional control can be performed.

3. Electroless nickel plating is a very common plating technology and does not require special equipment, so it is inexpensive and can handle large amounts of plating.

4. The electroless nickel plating layer has high adhesion to the material and is Hv60.
It has a hardness of 0.

Therefore, even if the armature and the core surface collide, the core surface is not deformed and the initial state can be maintained for a long time.

5. Has rust prevention effect.

The electroless nickel mica has the same excellent anti-corrosion effect as other mica, so it is possible to prevent the oxidation of the frame at the same time.

Since the electroless nickel plating having such characteristics is applied to the entire frame with a thickness of 20 to 40 μ, leakage flux of the frame outer peripheral portion 3c is generated, or the cost is not significantly increased by using an expensive material, Even if the platen gear is longer than the wire stroke and the suction surface of the armature contacts the frame core surface, the non-magnetic electroless nickel plating layer acts as an air gear and the actual armature and the magnetic material of the frame do not contact and remain. The influence of magnetic flux can be prevented. The curve a in FIG. 2 shows the wire behavior of the head applied with the present invention, and the return speed of the wire after the collision becomes larger than that of the prior art shown by c. For this reason, even if they are continuously driven, as shown in FIG. 3A, they are surely returned with each drive, and the ribbon is not caught and the fabric is not broken or the wire is not broken.

In the present invention, the electroless nickel plating is applied with a thickness of 20 to 40μ, but if the plating layer is formed thicker than this range, an air gear cup is unnecessarily large and secured on the surface 3c in contact with the yoke on the outer periphery of the frame, so this portion In this case, the leakage magnetic flux increases, and the predetermined magnetic flux density on the core / armature surface cannot be obtained. As a result, the printing energy of the armature is reduced, and the print density and the behavior are poor. On the contrary, when the thickness is less than the range of the present invention, the amount of the air gear gap that can be secured between the armature core and the armature core is too small to reduce the influence of the residual magnetic flux.

Another embodiment will be described with reference to FIG. Frame 3 is core 12
The frame plate 11 is crimped and configured. This core shows the characteristic of the present invention, and an electroless nickel plating layer is formed on the core 12 without heat treatment after 20 to 30 μm plating. The frame plate 11 is provided with a thin metal plate having a thickness of 2 to 5 .mu. (In this embodiment, electrolytic nickel plating.) In this case, only the core 12 needs to be plated, and no air gear is secured in the outer peripheral portion 3c of the frame plate, so that leakage flux is not increased.

Also in this embodiment, the effects described in the above embodiments can be achieved.

Also in the frame integrally manufactured with the core portion described in the first embodiment, the same effect can be obtained even if the electroless nickel plating is applied only to the core surface by masking at the time of plating.

<Advantages of the Invention> As described above, according to the present invention, the suction surface of the core has 20
Since the electroless nickel plating layer is formed within the range not exceeding 0 ° C, when the armature is sucked, this electroless nickel plating layer does not show magnetism. A gap equivalent to an air gap is formed between the and to eliminate the delay in recovery due to residual magnetic flux and improve responsiveness, enabling not only high-speed printing but also the dimensional accuracy required for the assembly of both. It is possible to replace the electrolytic nickel plating in the form of a layer thickness, which makes it easy to assemble this type of head and significantly reduce the manufacturing cost thereof.

Moreover, the hardness and chemical properties of this material make it possible to eliminate wear on the core surface and prevent rust, and to maintain this type of head in good condition for a long period of time.

[Brief description of drawings]

FIG. 1 is a sectional view of an impact dot head showing an embodiment of the present invention. FIG. 2 is a comparative diagram showing the wire behavior of the present invention and the prior art. FIG. 3 is a comparative diagram showing the continuous wire behavior of the present invention and the prior art. FIG. 4 is a sectional view of an impact dot head showing another embodiment of the present invention. 1: Wire, 2: Armature, 2a: Armature suction surface, 3: Frame, 3a: Frame core surface, 3b: Frame core part, 3c: Frame outer peripheral part, 3d: Electroless nickel plating layer,
4: Yoke, 5: Coil, 6: Reset spring, 7: Ink ribbon, 8: Paper, 9: Platen, 10: Damper rubber, 11: Frame plate, 12: Core

Claims (1)

[Claims] 1. A wire-type impact dot head of a type in which an armature carrying a printing wire at its tip is attracted by an electromagnet to perform printing, and the suction surface of a core for attracting the armature does not exceed 200 ° C. A wire type impact dot head characterized by being coated with a layer of electroless nickel plating.