JPH0624879B2 - Printhead manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] In the present invention, a plurality of armatures respectively driving a plurality of printing wires are radially arranged at predetermined intervals on substantially the same circumference. Is held in a state of being displaced so that a predetermined elastic energy can be stored in the elastic member by being engaged with a predetermined stopper member against the elastic force of the elastic member when it is inactive, The present invention relates to a method of manufacturing a print head configured to release a sheet and perform a printing operation by the elastic energy, and more particularly to a method of processing an armature body.

[Prior Art] Conventionally, as described in Japanese Patent Application No. 59-256251, for example, a method of manufacturing a print head of this type is configured such that each armature is in the same state as when it is inoperative, that is, its elasticity. The engaging surface, which is held in a deformed state so as to store a predetermined elastic energy against a force, and which is engaged with a predetermined stopper of each armature, has been surface-machined by electric discharge machining. With this manufacturing method, the armatures engaged with the stoppers all have the same elastic energy when the armatures are engaged, so that the elastic energy is the same when the armatures are engaged. Became uniform.

[Problems to be Solved by the Invention] By the way, the engaging surface of each armature machined by electric discharge machining has a rough surface, and the stopper engaging with the engaging surface is worn away, resulting in the life of the print head. Lowered.

In addition, the particles that have been dissolved and removed during electric discharge machining, that is, fine particles called electric discharge splash adhere to the side surface of the armature and the like. Since the worker uses a tool or the like to remove the adhered discharge splash, it takes a long time for the work, which causes a long manufacturing time of the print head. Furthermore,
This discharge splash enters between the engaging surface of the armature and the stopper due to the action of vibration or magnetic force when the print head is driven. As a result, the wear amount of the stopper was increased, and the life of the print head was further reduced.

An object of the present invention is to solve the above-mentioned conventional problems, to shorten the manufacturing time of the print head and to improve the life of the print head, and the load acting on each armature during grinding. To further improve the life of the print head.

[Means for Solving the Problems] In order to achieve the above object, the present invention applies a pressing force to each armature against the elastic force of an elastic member to bring each armature into the same state as when it is inoperative. Thus, the manufacturing method is performed in which the engaging surface of the armature engaged with the predetermined stopper member is ground by the rotating grinding member while rotating each armature in this state.

[Operation] According to the above-described manufacturing method, the present invention grinds the engaging surface of the armature by the grinding member without generating discharge splash, so that the surface roughness of the engaging surface is improved. As a result,
Wear due to surface roughness and discharge splash can be reduced.

Further, since the plurality of radially arranged armatures come into contact with the grinding member while rotating, the grinding direction for each armature changes sequentially. As a result, the load during grinding acts on the armature from many directions, and overload does not act on only a specific one of the elastic members that support the armature to prevent deformation or shortening the life. . Moreover, this makes the reaction of the elastic member uniform during the grinding process, and the engaging surface of each armature can be ground substantially uniformly.

[Embodiment] An embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 2, for example, the print head 10 manufactured in this embodiment includes a frame-shaped rear yoke 12 in the shape of a flat circular container and a front yoke 13 in the shape of a disk. An annular permanent magnet 14 and a spacer member 15 are interposed between the rear yoke 12 and the front yoke 13. A guide body 16 having a large number of guide holes 16a arranged on the front surface of the front yoke 13 is provided.
Is installed.

Between the front yoke 13 and the spacer member 15, the armature bodies 18 are fixed by screws in a state of being aligned in the radial direction on the same circumference at a predetermined interval. Each armature body 18 has a holder 19 having a base end fixed between the front yoke 13 and the spacer member 15 with a screw 19a, and a wire arm 21 having a print wire 22 attached to the tip thereof. A torsion spring 23, which is connected to the armature 20 and the holder 19 and the armature 20 in a single manner, and rotates the armature 20 in a direction orthogonal to its axis (left-right direction in FIG. 2) by elastic force.
It consists of and.

A large number of electromagnets 25 respectively corresponding to the armatures 20 are provided on the rear yoke 12, and a tip of the core 26 constitutes a stopper member facing the engaging surface 20a of the corresponding armature 20, and is wound around the core 26. The excitation coil 27 is mounted.

In such a print head, the permanent magnet 1 is always used.
4, spacer member 15, holder 19, armature 2
0, the core 26 and the rear yoke 12 form a magnetic path, and the armature 20 is attracted to the tip of the core 26 by this magnetic path. As a result, the torsion spring 23 interposed between the holder 19 and the armature 20.
Is twisted to the left in FIG. 2 and elastic energy is stored. When a pulse voltage is applied to the exciting coil 27 of the electromagnet 25, the electromagnet 25 generates a magnetic force that cancels the magnetic force of the permanent magnet 14, and the armature 20 corresponding to the electromagnet 25 has elasticity stored in the torsion spring 23. The elastic force generated by the release of energy causes the elastic member to rotate rightward in FIG. The rotation of the armature 20 causes the wire arm 2 to move.
2, the print wire 22 moves to the right in FIG.
It is designed to print.

FIG. 1 shows the front frame 13 of the print head 10,
Workpiece 3 including guide body 16 and armature body 18
A sectional view of a jig of a grinding machine in which 0 is mounted is shown. The jig body 31 has a cylindrical shape, and a protrusion 32 is provided above the inner side surface of the jig body 31. This protrusion 3
By 2, the workpiece 30 is positioned so that the workpiece surface of the workpiece 30 inserted from below the jig body 31 projects upward from the upper surface of the jig body 31 in FIG.

Further, two grooves 33 are provided on the inner side surface of the jig body 31 at positions facing each other, and a wire pushing plate 34 is inserted into the grooves 33 from below the jig body 31. The wire pushing plate 34 has a rectangular plate shape, and through holes 35 are formed at both ends thereof. The wire push-up plate 34 is fixed to the jig main body 31 by the step screw 36 inserted through the through hole 35, and the print wire 22 of the work piece 30 is pushed upward in FIG. Keep the same condition as when operating.

Further, the jig body 31 has its lower end fitted to the grinding chuck 37. The grinding chuck 37 is connected to a driving device (not shown) and is rotated at a low speed during the grinding work.

A grinding wheel 40 is arranged so as to face the workpiece 30 mounted on the jig body 31. This grinding wheel 40
An elastic grindstone using a binding material having elasticity is used to bond the abrasive grains. As shown in FIG. 1, engagement of the armature 20 which is the machined surface on the flat side surface 40a substantially orthogonal to the rotation axis thereof. It is connected to a driving device (not shown) so as to grind the surface 20a. Then, the grinding wheel 40 is rotated at a high speed in the same direction as the grinding chuck 37 during the grinding work.

The grinding process using the flat side surface 40a of the grinding wheel 40 is called creep feed grinding. In the present embodiment, the workpiece 30 and the grinding wheel 40 are rotated in the same direction, so that the grinding resistance is small.

Next, a method of processing the armature body 18 will be described.

The front yoke 13 of the workpiece 30 from below the jig body 31
Insert until the circumferential portion of is in contact with the protrusion 32. Next, the wire push-up plate 34 is inserted along the groove 33, and is fixed to the jig body 31 by the step screw 36 inserted in the through hole 35. The printing wire 22 is made by the jig body 31 and the wire lifting plate 34.
Is pushed upward in FIG. 1 to hold the armature body in the same state as when it was inoperative. In this way, the jig body 31 on which the workpiece 30 and the wire push-up plate 34 are mounted is fitted into the grinding chuck 37, while the grinding wheel 40 is arranged at a position facing the grinding chuck 37.

When the switch of the grinding machine is turned on while keeping this state, the grinding chuck 37 starts rotating at the low speed and the grinding wheel 40 starts rotating at the same speed in the same direction. Then, the grinding wheel 40 moves downward in FIG. 1 to grind the surface of the engaging surface 20a of the armature 20. The grinding time is usually about 5 minutes. Further, during the grinding process, since the many armatures 20 are rotating in the array circle direction, the grinding direction by the grindstone 40 is sequentially changed. Therefore, the load applied to the armature at the time of grinding acts from almost any direction parallel to the grinding surface, and only a specific one of the torsion springs 23 supporting the armature is overloaded and deformed or the life is shortened. Never shrink. Moreover, as a result, the reaction of the torsion spring 23 during grinding becomes uniform for each armature, so that the ground surface of each armature can be made substantially uniform.

After the grinding process is completed, the shavings generated during this process are blown off using air, and then the jig body 31 is removed from the grinding chuck 37 and the work piece 30 is taken out.

Each of the armature bodies 18 thus ground is processed by the wire push-up plate 34 in the same state as when the core 2 is not in operation.
Since the engaging surface 20a with 6 is formed, the armature 2
When 0 is attracted to the core 26, each armature body 18 has the same elastic energy, and when the printing operation is performed, the printing pressure of the printing wire 22 becomes uniform.

Further, since the surface roughness of the engagement surface 20a formed by grinding is about 1/10 of that of the surface formed by electrical discharge machining, the amount of wear of the core engaging with the engagement surface 20a is reduced and the print head of the print head is reduced. Lifespan is extended.

Electric discharge splash does not occur during grinding, but shavings are generated by the grinding wheel. However, this shavings can be blown off by air, and the work of removing with a tool like the electric discharge splash is unnecessary. As a result, the processing time can be shortened to about 1/10.

[Advantages of the Invention] As described in detail above, according to the present invention, by grinding the engaging surface of each armature with a rotating grinding member, the surface roughness of the engaging surface is improved and a discharge splash is also generated. do not do. Therefore, the amount of wear of the stopper member is reduced, and the life of the print head is improved. Further, since it is not necessary to remove the discharge splash in the manufacturing process, the manufacturing time can be shortened. Further, since a plurality of radially arranged armatures come into contact with the grinding member while rotating, the load acting on the armature during grinding sequentially changes its direction and acts uniformly on each armature. As a result, overload does not act on only a specific elastic member that supports the armature, and the life of the elastic member is not shortened. Moreover, this makes the reaction of the elastic member uniform during the grinding process, and the engaging surface of each armature can be ground substantially uniformly.

[Brief description of drawings]

FIG. 1 is a sectional view of a grinding jig, and FIG. 2 is a sectional view showing an inoperative state of a print head. In the figure, 18 is an armature body, 20a is an engaging surface, 22 is a printing wire, 23 is a torsion spring (elastic member), 26
Is a core (stopper member).

Claims (2)

[Claims] 1. A plurality of armatures (20) for respectively driving a plurality of printing wires (22) are radially arranged at predetermined intervals on substantially the same circumference, and when the respective armatures (20) are inoperative. By being engaged with a predetermined stopper member (26) against the elastic force of the elastic member (23), the elastic member (23) is held in a displaced state so as to store a predetermined elastic energy, In a print head configured to release its holding during operation and perform a printing operation by the elastic energy, a pressing force is applied to each armature (20) against the elastic force of the elastic member (23). , Armatures (20)
Is held in a state similar to that in the inoperative state, and while rotating each armature (20) in that state, the armature (20) engaged with the stopper member (26).
A method for manufacturing a print head, wherein the engaging surface (20a) of (1) is ground by a rotating grinding member (40). 2. The grinding member (40) has a flat side surface (40a) which is substantially orthogonal to a rotation axis and an engagement surface (20a) of an armature (20) facing each other, and the engagement surface (20a) is ground. The method of manufacturing a print head according to claim 1, wherein the method is manufacturing.