JPH0767811B2 - Moving coil type print head hammer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Overview] A hammer for a moving coil type print head used in a wire dot printer, etc., which prevents interference due to air expansion of the air core of the flat coil, and is robust and lightweight. For the purpose of providing a hammer that operates smoothly over a long period of time, a hammer with dot pins at its tip electromagnetically acts on permanent magnets arranged on both sides to perform printing. A hammer for a moving coil type print head, wherein the hammer is
A plate-shaped base supported by a leaf spring, a flat coil adhered to the base via a film-shaped adhesive sheet, and a protective sheet attached to the surface of the flat coil,
A dot pin provided at the tip of the base, a recess is formed in the center of the base, and a hole for reducing the weight is provided in the recess, and the adhesive sheet is An adhesive agent is applied to both surfaces of the flat coil, and a ventilation hole for opening the air core of the flat coil to the atmosphere is provided so as to communicate with the vent hole. The coil is configured to be bonded in a state of being fitted in the recess and in a state of sandwiching the adhesive sheet with the recess.

[Industrial application field]

The present invention relates to a moving coil type print head hammer used in a wire dot printer or the like.

The moving coil type print head may suffer from print blurring or pin breakage due to long-term use, which hinders the long life and high reliability of the print head.

Therefore, in order to improve the reliability of the print head, it is necessary to adopt a structure in which the hammer operating at high speed operates smoothly over a long period of time.

[Conventional technology]

FIG. 3 is a sectional front view of a general moving coil type print head 1.

The print head 1 includes a substrate 11, a large number (for example, two sets of 12) of hammers 52 arranged in a direction perpendicular to the paper surface, a pot 13 for fixing the hammers 52 to the substrate 11, and two pots. Each of the hammers 52 is composed of a permanent magnet 14 attached to the substrate 11 on both sides (for example, Japanese Patent Laid-Open No. 60-183167).
issue).

FIG. 4 is a cross-sectional view of the conventional hammer 52. The structure will be described with reference to FIG. 1 which is an exploded perspective view of the hammer 12 according to the present invention.

The hammer 52 is attached to the plate-shaped base 21, the flat coil 23 attached to the base 21 via the film-shaped adhesive sheet 22, the protective sheet 24 attached to the surface of the flat coil 23, and the base 21. It is composed of a leaf spring 25 and a dot pin 26.

The tip of the leaf spring 25 is fixed in the pot 13 with an adhesive, and the pot 13 is fixed to the substrate 11 by screws or welding, which allows the hammer 52 to swing with respect to the substrate 11. It is supported.

When the flat coil 23 is energized, the base 21 moves downward with respect to the leaf spring 25 as a fulcrum, and the dot pin 26 projects downward from the substrate 11 for printing. When the current stops, the elastic force of the leaf spring 25 causes the base 21 and the dot pin 26 to return to their original positions.

[Problems to be Solved by the Invention]

In the conventional hammer 52 described above, the air core portion 27 of the flat coil 23 is
However, since it is sealed by the adhesive sheet 22 and the protective sheet 24 that are adhered to both sides of the flat coil 23, the air in the air-core portion 27 cannot go in and out.

Therefore, by energizing the flat coil 23, the flat coil 23
The temperature of 23 rises, which also raises the temperature of the air in the air-core part 27, and as a result, the air expanded due to the temperature rise pushes the adhesive sheet 22 and the protective sheet 24 outward and expands them.

By the way, the gap between the adjacent hammers 52 and the hammer 52
The clearance between the permanent magnet 14 and the permanent magnet 14 is as narrow as several hundredths of a millimeter. Or it gets caught.

Therefore, the hammer 52 does not operate smoothly, and the hammer 52
Operation response speed and recovery speed are slowed down, the print quality is deteriorated, and the dot pin 26
Can lead to serious obstacles such as breakage.

In order to operate the print head hammer smoothly over a long period of time, it is necessary to have a structure that prevents the hammer from mechanically interfering with other members, and also to make the hammer itself a robust structure and make it as light as possible. Is.

In view of the above problems, the present invention provides a hammer that prevents interference due to air expansion of the air-core portion of the flat coil, and that is robust and lightweight, and that operates smoothly over a long period of use. The purpose is to do.

[Means for Solving the Problems]

The present invention is, in order to solve the above problems, a hammer of a moving coil type print head in which a hammer having a dot pin at its tip electromagnetically acts with permanent magnets arranged on both sides to perform printing, The hammer is a plate-shaped base supported by a leaf spring, a flat coil adhered to the base via a film-shaped adhesive sheet, a protective sheet attached to the surface of the flat coil, and the base. A dot pin provided at the tip, a recess is formed in the center of the base, and a hole for reducing the weight is provided in the recess, and the adhesive sheet is made of synthetic resin. An adhesive agent is applied to both surfaces of the flat coil, and a vent hole for opening the air core of the flat coil to the atmosphere is provided so as to communicate with the vent hole, and the flat coil is The above In fitting state forme Mari at, and configured by bonding in a state sandwiching the adhesive sheet by the said recess.

[Work]

As shown in FIG. 1, the flat coil 23 is adhered to the recess 21 a of the base 21 with the adhesive sheet 22 sandwiched therebetween, and the surface thereof is protected by the protective sheet 24.

Since the side surface of the flat coil 23 is in contact with the base 21 via the adhesive sheet 22, the heat generated by the flat coil 23 is easily transferred to the base 21, and the heat dissipation effect is good.

The air-core portion 27 of the flat coil 23 is open to the atmosphere through a vent hole 35 provided in the adhesive sheet 22 and a vent hole 33 provided in the base 21, and air can freely flow in and out.

When the flat coil 23 is energized and the temperature of the air in the air-core portion 27 rises and expands, the expanded air passes through the vent hole 35 and the vent hole 33 and escapes to the outside.

By forming the recess 21a in the base 21, even if the plate thickness is the same, the rigidity is higher than that of a flat plate, and the hammer 12 as a whole is robust. Further, since the punched hole 33 is provided and the adhesive sheet 22 is made of synthetic resin, the weight of the hammer 12 is reduced.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view of a hammer 12 according to the present invention, and FIG. 2 is a cross sectional view of the hammer 12.

The description of the matters described in the section of the related art will be omitted or simplified here.

The hammer 12 is a plate-shaped base 21 having a recess 21a formed in the center thereof, and a flat coil adhered to the recess 21a of the base 21 via a film-like adhesive sheet 22.
23, the protective sheet 24 attached to the surface of the flat coil 23, and the leaf spring 25 and the dot pin 26 attached to the base 21.
It consists of

The base 21 is obtained by press-molding a thin stainless steel plate, and has a recess 21a formed by press-molding and holes 31 to 34 for reducing the weight.

The adhesive sheet 22 has a three-layer structure in which an epoxy thermosetting resin adhesive is applied on both sides of a thin film made of polyimide, and is heated to about 160 ° C. Adhere in close contact with.

The adhesive sheet 22 is provided with a vent hole 35 for opening the air core portion 27 to the atmosphere at a position corresponding to the hole 33 of the base 21. The vent holes 35 are formed at the same time when the outer shape of the adhesive sheet 22 is press-molded, for example.

The protective sheet 24 is a thin resin film coated with an adhesive on one side.

In the hammer 12 configured as described above, since the air core portion 27 of the flat coil 23 is opened to the atmosphere by the vent hole 35 and the vent hole 33, the flat coil 23 is energized by energizing the flat coil 23.
Even if the temperature rises, the air expanded by the temperature rise escapes to the atmosphere through the ventilation hole 35 and the vent hole 33, so that the protective sheet 24 is prevented from expanding. Further, since the air in the air-core portion 27 circulates, the flat coil 23, the adhesive sheet 22 and the like are cooled, and the temperature fluctuation and the temperature gradient of the hammer 12 are alleviated.

Therefore, the use of the print head 1 does not cause interference due to the bulging of the protective sheet as in the conventional case, and suppresses the thermal deterioration of the hammer 12, so that the hammer 12 operates smoothly for a long period of time and the operation is stable. .

Further, since the recess 21a is formed in the base 21, the rigidity is higher than that of a flat plate-like one having the same plate thickness, and the hammer 12 as a whole is solid. Also, for ventilation, there is a hole in the base 21 to reduce the weight.
33 are being used successfully. Since the side surface of the flat coil 23 is in contact with the base 21 via the adhesive sheet 22, the heat generated by the flat coil 23 is easily transferred to the base 21, and the heat dissipation effect is good. Since the adhesive sheet 22 and the protective sheet 24 are made of synthetic resin, the weight of the hammer 12 can be reduced. These allow the hammer 12 to operate smoothly for a longer period of time.

In the above-described embodiment, the ventilation holes 35 are formed at the same time when the adhesive sheet 22 is molded, but the processing for opening the ventilation holes 35 may be performed after the assembly of the hammer 12 is completed. Although the ventilation holes 35 are provided in the adhesive sheet 22, they may also be provided in the protective sheet 24. Although the lightening hole 33 provided in the base 21 is also used as a ventilation hole, the other holes 31, 32, 34 may be used as well. The shapes and dimensions of the vent holes 31 to 34 and the vent holes 35 may be any other suitable than those described above.

In the above-described embodiment, the structure, shape, material, size, etc. of the hammer 12 or each part of the print head 1 can be various other than those described above.

〔The invention's effect〕

According to the present invention, it is possible to provide a hammer that prevents interference due to expansion of air in the air-core portion of the flat coil and that is robust and lightweight, and that operates smoothly over a long period of use.

Therefore, it is possible to extend the service life and increase the reliability of the print head.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a hammer according to the present invention, FIG. 2 is a transverse sectional view of the hammer, FIG. 3 is a sectional front view of a general moving coil type print head, and FIG. 4 is a conventional hammer. FIG. In the figure, 1 is a print head, 12 is a hammer, 14 is a permanent magnet, 21 is a base, 21a is a recess, 22 is an adhesive sheet, 23 is a flat coil, 24 is a protective sheet, 25 is a leaf spring, and 26 is a dot pin. , 27 is an air core, 33 is a hole, and 35 is a vent.

Claims (1)

[Claims] 1. A hammer for a moving coil type print head, in which a hammer having a dot pin at its tip works electromagnetically with permanent magnets arranged on both sides of the hammer to print, wherein the hammer is a leaf spring. A supported plate-shaped base, a flat coil adhered to the base via a film-shaped adhesive sheet, a protective sheet attached to the surface of the flat coil, and a dot pin provided at the tip of the base. A recess is formed in the center of the base, and a hole for reducing the weight is provided in the recess, and the adhesive sheet is made of synthetic resin and adheres to both sides thereof. An agent is applied, and a ventilation hole for opening the air core of the flat coil to the atmosphere is provided so as to communicate with the vent hole, and the flat coil is fitted in the recess. Is In state, and the recess and the hammer of the moving coil type print head is characterized by comprising adhered in a state sandwiching the adhesive sheet by.