JPH0899418A - Armature of wire dot printing head, intermediate article thereof and manufacture of armature - Google Patents

Abstract

PURPOSE: To contrive to enhance the yield of an armature and to stabilize its soldering strength by a method wherein stable dimensional accuracy of a groove of the armature, into which a lever is inserted, is realized. CONSTITUTION: In this armature 31 of a wire dot printing head having a groove 35, into which a lever fixed by a wire is inserted, beams 37a and 37b are arranged at both the longitudinal ends or either one end of them. In order to manufacture the intermediate article of the armature, after the intermediate article being formed under the state that the beams 37a and 37b are arranged, the beams 37a and 37b are removed by grinding the top bottom surfaces 33b and 33a, which are normal to the longitudinal direction of the groove 35, of the armature 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an armature of a wire dot print head in a serial printer, an intermediate product thereof, and a method of manufacturing the armature.

[0002]

2. Description of the Related Art In recent years, wire dot print heads have achieved higher speeds due to advances in drive control methods, and recently, printers with a response frequency exceeding 4 KHz have also appeared.
As one of the means for realizing these high speeds, a thin plate of structural metal is used for the member connecting the wire and the armature, and the weight of the movable part is reduced. A spring charge type wire dot print head using this type of armature will be described with reference to FIG. A core 7 having a coil 5 wound around one end of a base yoke 3 arranged above the head substrate 1.
And the core 7 forms an electromagnet by the coil 5. A permanent magnet 11 sandwiched between the yokes 9a and 9b is provided on the other end of the base yoke 3, and a base end of a bias leaf spring 13 is held on the upper surface side of the yoke 9b. The base end of the armature 15 is fixed to the free end of the leaf spring 13, and the armature 15 is connected to the wire 19 via a lever 17 which is a thin plate of structural metal.

In the wire dot print head thus constructed, the coil 5 is excited for a short period of time by the operation of the circuit connected to the head substrate 1 at the time of printing, and the magnetic flux of the permanent magnet 11 is canceled to thereby cause the leaf spring. 13 is core 7
That is, the wire 19 moves in the direction of arrow A by being released from the suction force. FIG. 4 is a perspective view showing the structure of a conventional armature. Armature 1 that works this way
5, the lever 17, and the wire 19 are fixed to each other by brazing to form a single assembly, which constitutes a movable body.
Then, a groove 21 suitable for brazing is formed on the lever fixing side of the armature 15, and the lever 17 is fitted into the groove 21.
After brazing it with a wire and performing predetermined positioning, brazing was performed.

[0004]

The armature 15 having the groove 21 described above requires a lot of time and labor for machining.
In addition, since an expensive magnetic material is used in many cases, it is manufactured by the lost wax method or sintering which is relatively inexpensive in terms of cost. Then, in the armature 15 molded by these manufacturing methods, burrs generated during molding were removed by barrel polishing. In this barrel polishing, a workpiece (armature as an intermediate product), a grindstone of several millimeters, and an abrasive are put in a container (barrel), and the container is rotated or vibrated so that the workpiece and the grindstone are relatively slid to each other. It was possible to polish the processed products at the same time. However, in barrel polishing, if the container is moved slowly with a small grindstone, the effect on the workpiece is small, but in the armature as an intermediate product, the strength of the tip portion where the groove 21 is formed is particularly low, and a general barrel polishing machine is used. Under the above polishing conditions, the groove 21 is deformed, and the lever 17 cannot be inserted. Further, in the cast molding such as the lost wax method, the cooling rate is different due to the difference in the wall thickness of each part of the casting, and the internal stress is generated due to the difference in the shrinkage amount due to the temperature difference. In the product, as shown in FIGS. 5A and 5B, the processed armature 15 has a defect that the groove 21 is deformed such that the groove 21 is narrowed or expanded, and stable dimensional accuracy cannot be obtained. The present invention has been made in view of the above circumstances, and provides an armature capable of obtaining a stable dimensional accuracy of a groove portion, an intermediate product thereof, and a method of manufacturing an armature using the intermediate product, thereby improving yield and brazing strength. The purpose is to stabilize the.

[0005]

To achieve the above object, an armature of a wire dot print head according to the present invention has a groove for inserting a lever to which a wire is fixed. The beam is arranged at either one of the ends, and the intermediate product is characterized in that the beam is arranged at both ends in the longitudinal direction of the groove or at either one of the ends. The method for manufacturing an armature according to the present invention is a method of molding an intermediate product of an armature in a state where a beam is arranged on at least one end of both longitudinal ends of a groove,
The armature is manufactured by grinding the ends of the grooves in which the beams are arranged to remove the beams.

[0006]

In the armature, the both side surfaces of the groove are connected by the beams so that the groove is integrated, and strength is generated against the stress that deforms the groove. In the manufacturing method using such an armature intermediate product, since the groove is formed in a state in which the beam is temporarily installed, this beam plays a role of protecting against a factor that deforms the groove, and the beam is finished after the grinding process is completed. As a result of the removal, the groove is formed as a finished armature without being affected by the deformation factor.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of an armature of a wire dot print head, an intermediate product thereof and a method of manufacturing the armature according to the present invention will be described below with reference to the drawings. FIG. 1 is an armature (intermediate product) of the wire dot print head of the present invention.
FIG. The prismatic armature 31 has a tapered tip and a rectangular tip surface. Grooves 35 parallel to both side surfaces 33a, 33a are formed on the tip end surface, and the grooves 35 are formed with a groove width having a slight gap with respect to the thickness of the lever. Thin-film beams 37a and 37b having a thickness of about 0.02 mm are provisionally provided at both ends of the groove 35 in the longitudinal direction, and the beams 37a and 37b close both ends of the groove 35.
That is, the groove 35 is formed into a rectangular hole by the side surfaces 33a and 33a and the beams 37a and 37b on the tip end surface of the armature 31, and the tip end is open. The armature 31 is formed by sintering, forging, or casting such as die casting or lost wax method.

In the armature 31 as an intermediate product having the above-mentioned structure, both side surfaces 33a, 33a of the groove 35 are formed by the beam 3.
The opposing walls that are connected by 7a and 37b and form the groove 35 are integrated, and have strength against the stress that deforms the groove 35. Therefore, the provision of the beams 37a and 37b improves the strength of the armature 31 as an intermediate product against internal stress generated during molding and external force acting during barrel polishing, and prevents deformation of the groove 35 such as crushing and spreading. Therefore, the armature 31 as a finished product
The dimensional accuracy of the groove width is always stable.

FIG. 2 is an explanatory view of inserting the lever by additionally machining both side surfaces of the armature at both ends of the groove. The armature 31 is provided with a beam 37 before the thin plate lever 39 is inserted.
Remove a and 37b. The removal of the beams 37a and 37b is performed by performing additional work such as grinding the upper and lower surfaces 33b and 33b of the armature 31 with a grindstone grinder (at least the beams 37a and 37b).
a, 37b or more). By this grinding, the beams 37a and 37b are removed from the groove 35, and the both ends are opened to become the groove 35 which is free in the longitudinal direction, and the lever 39 longer than the length of the groove 35 can be inserted.

As described above, the armature 31 as an intermediate product has a very large strength against the factor of deforming the groove that acts at the time of molding or barrel polishing due to the existence of the beams 37a and 37b. Since the shape of the groove 35 is formed only in the finishing step after the processing steps having these deformation factors are completed, the grooves 35 are not affected by the deformation factors. Armature 31 as a finished product
Will have a high groove dimensional accuracy. As a result, defective fitting between the armature 31 and the lever 39 and defective joining due to the expansion of the groove 35 can be eliminated in the process of assembling the movable body, and the yield and the reliability of the brazing state can be significantly improved.

In the above-mentioned embodiment, the beams 37a, 37 are provided.
Although b is provided at both ends of the groove 35, the beam may be provided at either end of the groove 35, and in this case, additional work for removing the beam can be reduced. Also, beam 3
When 7a and 37b are provided in the groove 35, the beam to be removed by the additional machining is only on either side of the upper surface or the lower surface, and one of the beams remains so that the lever 3 longer than the groove length can be obtained.
The insertion position of 9 can be secured, and additional work can be reduced. Further, the beam is erected only in the groove opening of the armature tip surface, that is, the elongated beam is attached to both side surfaces 33a, 33.
The groove 35 can be bridged between a and, in this case, not only the strength of the groove 35 can be improved, but also the groove 35 having an open end is formed by grinding only the armature tip surface. An armature can be formed.

[0012]

As described in detail above, according to the armature and the intermediate product of the wire dot printing head according to the present invention, the strength against the factor of deforming the groove that acts at the time of molding or barrel polishing is extremely high. Can be generated. Further, according to the armature manufacturing method using the intermediate product, since the shape as the groove is formed for the first time after the processing step having the deformation factor is completed, the groove is not affected by the deformation factor and is completed. It is possible to remarkably improve the accuracy of the subsequent groove dimension. As a result, the yield can be improved and the brazing strength can be stabilized.

[Brief description of drawings]

FIG. 1 is a perspective view showing an armature (intermediate product) of a wire dot print head according to the present invention.

FIG. 2 is a view showing a state in which a lever is inserted into an armature completed by additionally machining both ends.

FIG. 3 is a cross-sectional view of a spring charge type wire dot print head.

FIG. 4 is a perspective view of an armature to which a conventional lever is attached.

FIG. 5 is an explanatory diagram when a groove is deformed.

[Explanation of symbols]

19 wire 31 armature 33a groove end 33b upper and lower surfaces of armature 35 groove 37a, 37b beam 39 lever

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location B41J 3/10 115 (72) Inventor Masahiro Hatano 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industrial Co., Ltd. (72) Inventor Hiroshi Kihara 1 Kanda Mitoshiro-cho, Chiyoda-ku, Tokyo Sumitomo Cement Co., Ltd. (72) Inventor Hideki Arai 1 Kanda-Midoshiro-cho, Chiyoda-ku, Tokyo Sumitomo Cement Co., Ltd.

Claims (3)

[Claims] 1. An intermediate product of a wire dot print head armature having a groove into which a lever to which a wire is fixed is inserted, the beam being provided at both ends in the longitudinal direction of the groove or at one end thereof. The intermediate product of the armature for the wire dot print head, characterized in that 2. An armature for a wire dot print head having a groove for inserting a lever to which a wire is fixed, wherein a beam is arranged at both ends in the longitudinal direction of the groove, or at either one end. An armature for a wire dot printing head, wherein the beam is formed by grinding an intermediate product, and a beam is left on either one of both ends of the groove. 3. A method for manufacturing an armature of a wire dot print head having a groove for inserting a lever to which a wire is fixed, wherein a beam is provided at both ends in the longitudinal direction of the groove or one end thereof. In the intermediate product in which the intermediate product of the armature is formed in the installed state and then the beams are arranged at both ends, at least one beam is removed by grinding the upper and lower surfaces of the intermediate product, or A method for manufacturing an armature, characterized in that, in an intermediate product having a beam arranged at one end, the upper and lower surfaces of the intermediate product are ground and the beam is left or removed.