JPH0624878B2 - Printhead manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention has a plurality of armatures respectively driving a plurality of printing wires arranged on substantially the same plane, and when each armature is inoperative, its own elastic force. By being engaged with a predetermined stopper against the force, it is held in a deformed state so as to store a predetermined elastic energy, and the holding is released at the time of operation so that the printing operation is performed by the elastic energy. The present invention relates to a method for manufacturing a printed print head, and particularly to a method for processing an armature.

[Prior Art] A print head of this type is generally constructed as shown in FIG. 6, and a frame 1 comprises a rear yoke 2 in the shape of a flat circular container and a front yoke 3 in the shape of a disk. Becomes
An annular permanent magnet 4 and a spacer member 5 are interposed between the rear yoke 2 and the front yoke 3. Further, a large number of guide holes 13a are formed on the front surface of the front yoke 3.
A guide body 13 in which are arranged is attached.

A large number of leaf springs 6 constituting the armature are formed so as to radially project inward from an annular base plate 7, and the base plate 7 serving as the base end of the armature includes the spacer member 5 and the front yoke 3. It is clamped between and fixed. An armature body 8 that constitutes an armature together with the leaf spring 6 is fixed to the free end of each leaf spring 6 by brazing, and a base end of the printing wire 9 is fixed by brazing. . The armature body 8 is slidably engaged with a notch (not shown) provided in the front yoke 3,
The movement is guided. A plurality of electromagnetic elements 10 respectively corresponding to the leaf springs 6 are provided on the rear yoke 2 so as to project from the rear yoke 2 and the tips thereof face the back surface of the free end portion of the corresponding leaf spring 6 to form a stopper. It is composed of an exciting coil 12 wound around 11.

The leaf springs 6 are always provided with a permanent magnet 4, a spacer member 5, a substrate 7, a front yoke 3, an armature body 8,
By forming a magnetic path consisting of the leaf spring 6, the core 11 and the rear yoke 2, the magnetic force of the permanent magnet 4 attracts the core 11, and the free end is displaced rearward to store the spring force. There is. Thus, the exciting coil 12 of the electromagnet 10
When a pulse voltage is applied to the electromagnet 10, the electromagnet 10 generates a magnetic force that cancels the magnetic force of the permanent magnet 4, and the free end of the leaf spring 6 corresponding to this electromagnet 10 is stored in the accumulator spring. Due to the force, it moves to the right side in FIG. 6 which is the front side and moves the printing wire 9 at its free end in the same direction as shown in FIG. Dot printing is performed.

Conventionally, as shown in FIG. 4, the processing of the armatures 6 and 8 in such a print head is performed by using an annular substrate 7
And a large number of, for example, 24 leaf springs 6 radially protruding inward from the substrate 7 are integrally formed by pressing or the like. At this time, the substrate 7 is provided with 24 tightening holes 7a and a pair of reference holes 7b at the same time. Next, as shown in FIG. 4, the brazing material and the armature body 8 are placed on the front side of the free end of the leaf spring 6, and the leaf spring 6 is attached to the leaf spring 6 at a high temperature of about 1100 ° C. in an atmosphere furnace. The armature body 8 is brazed. After that, the surfaces of the leaf springs 6 corresponding to the cores 11 of the electromagnets 10 are surface-machined by electric discharge machining so that the surfaces become the same plane, and the armatures 6 and 8 are machined. Therefore, each armature 6 and 8 incorporated in the print head
In the non-actuated state where the core spring 11 is sucked by the core 11, the leaf springs 6 are moved and held by substantially the same movement amount.

[Problems to be Solved by the Invention] As described above, each armature is composed of a leaf spring 6 integrally formed from a single substrate by pressing or the like and an armature body brazed to its free end. . However, each armature cannot be formed exactly the same in terms of material and shape in manufacturing, so that the elasticity of each armature is slightly different, and the elastic energy stored in each armature when inoperative is slightly different. Therefore, there is a drawback that the printing pressure at the time of printing operation by the printing wire is slightly different, in other words, the density of the printed dots is different, and it is difficult to distinguish the printed typeface.

An object of the present invention is to provide a method of manufacturing a print head capable of printing a typeface which is easy to distinguish by making elastic pressure energy stored in each armature constant during non-operation so that the printing pressure of the printing wire during operation becomes uniform. Is provided.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, each armature is counteracted against the elastic force so that the armatures have substantially the same elastic energy when inoperative. There is adopted a means for applying a pressing force to each of the armatures, which is maintained in a deformed state independently of each other, and which causes the engaging surface of the armature engaged with a predetermined stopper to be surface-machined by electric discharge machining.

[Operation] According to the present invention, all the engaging surfaces with the stoppers are formed in the same plane when the armature is deformed by applying a predetermined pressing force by the method shown in the above-mentioned means. The elastic energies of the armatures engaged with the stoppers are all the same, and the printing pressure of the printing wire during operation is uniform. Also, because the armature is machined by electrical discharge machining without applying a mechanical load, the grinding direction for each armature arranged radially is different, as when grinding all armatures at once with a grinding wheel. Moreover, the stress acting on each armature does not differ from each other and the machining amount does not become uneven, and the elastic energy of the armature can be more accurately aligned as described above.

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

A jig for electric discharge machining is shown in FIGS. 1 to 3, and a pair of reference pins that can be fitted into the reference holes 7b and 7b provided in the substrate 7 are provided on the upper surface of the jig body 14. Fifteen, fifteen
Is provided inside the armature body 8 of the leaf spring 6.
The hole portion 16 is provided so that it does not hit the jig body 14.

Further, a holding plate 19 is detachably attached above the jig body 14 along a guide pin 18 provided on the upper surface of the jig body 14, and the electric discharge machine is provided at the center of the holding plate 19. Through holes (not shown) are provided so that electrodes (not shown) can be inserted.

The jig body 14 is a machining tank (not shown) of the electric discharge machine.
Fixed inside.

Further, the pressure device shown in FIG. 1 is arranged inside the jig body 14 below the leaf spring 6 installed on the reference pins 15, 15. Inside the machine frame 20, there is provided a cavity 20c through which a polymer fluid is supplied and discharged through a supply port 20a and a discharge port 20b provided in the machine frame 20, and above the cavity 20c, which communicates with the cavity 20c. 24 cylinders 21 are installed so as to correspond to the respective leaf springs 6. A piston 22 is vertically movably inserted into the cylinder 21, and a pressure pin 22a is fixed to the upper portion thereof.

Further, the switching valve 2 is provided at the inlet 20a and the outlet 20b.
A relief valve 24 and a polymer fluid tank 25 are connected to each other via a valve 3. Also, the relief valve 24
A pump 27 which is driven by a motor 26 is connected to the tank, and the relief valve 24 and the pump 24 are connected to the tank 25.

Next, a method of processing the armature 6 will be described.

Reference pin 15 of jig body 14 fixed to the electric discharge machine
Then, set the leaf spring 6 brazed with the armature 8 so that the armature body 8 is on the lower side, and press the holding plate 1 on it.
9 is placed and fixed by the clamp 20.

Then, when the solenoid 23a of the switching valve 23 is operated to switch the switching valve 23 from the state shown in FIG. 1, the pump 27 driven by the motor 26 acts to cause the tank 25 to operate at a predetermined pressure (approx. 350 g /
The polymer fluid also supplied in mm ² ) is supplied into the cavity 20c of the machine casing 20 from the inlet 20a, and each piston 22 is moved upward. By the upward movement of the piston 22, the armatures 6 and 8 are pressed with a predetermined pressure via the pressure pin 22a, and are deformed so as to have the same elastic energy as shown by the chain line in FIG. To be done.

While maintaining this state, turn on the switch of the electric discharge machine
When this is set, the processing liquid is supplied into the processing tank and the jig body 14
After being dipped in the working liquid, the electrode 30 is lowered from above to work the surface of the leaf spring 6 on the side where the armature body 8 is not brazed. This electrical discharge machining time is usually 7 to
9 minutes is enough.

After the electric discharge machining is completed and the machining fluid in the machining tank is discharged,
After releasing the clamp 20, the pressing plate 19 is removed and the plate spring 6 is taken out, whereby the working operation is completed.

Each of the leaf springs 6 machined in this way has an engaging surface with the core 11 which is deformed by the pressure device so as to have substantially the same elastic energy when it is inoperative, and the leaf springs 6 are formed by electric discharge machining. When the leaf spring 6 is attracted to the core 11 as shown in FIG. 6, since it is machined substantially uniformly without applying a mechanical load, that is, without being affected by the reaction of the deformed leaf spring. , Each armature 6, 8 will have the same elastic energy.

Therefore, when the printing operation is performed, the printing pressure of the printing wire 9 becomes uniform.

[Effects of the Invention] As described in detail above, according to the present invention, each armature is held in a deformed state so as to have substantially the same elastic energy when not in operation, and the engaging surface engaged with the stopper is subjected to electric discharge machining. Therefore, the armature in its deformed state can be processed almost uniformly without being affected by the reaction, and as a result, the elastic energy stored in each armature when not in operation can be more accurately aligned, and the printing pressure of the printing wire during operation can be improved. Therefore, it is possible to provide a method for manufacturing a print head that can perform printing that is uniform and easy to determine.

[Brief description of drawings]

FIG. 1 is an enlarged vertical sectional view showing a pressure device, FIG. 2 is a vertical sectional view of a jig body, FIG. 3 is a side view showing a state in which a leaf spring is fixed to a jig, and FIG. A plan view, FIG. 5 is a sectional view showing a leaf spring brazed with an armature body taken along line AA in FIG. 4, and FIG. 6 is a longitudinal sectional view showing an inactive state of a print head. The drawing is a longitudinal sectional view showing a printing operation state of the print head. In the figure, 6 and 8 are a leaf spring and an armature body that constitute an armature, 7 is a substrate, 9 is a printing wire, and 11 is a core that constitutes a stopper.

Claims (1)

[Claims] 1. A plurality of armatures (6, 8) respectively driving a plurality of printing wires (9) are arranged on substantially the same plane,
When each of the armatures (6, 8) is inoperative, the armatures are engaged with a predetermined stopper (11) against an elastic force, so that the armatures are held in a deformed state so as to store a predetermined elastic energy,
In a print head configured to release its holding when activated and perform a printing operation by the elastic energy, the armatures (6, 8) are set to have substantially the same elastic energy when inoperative. , Each of the armatures that is independently deformed by applying a pressing force against the elastic force and is engaged with the stopper (11).
A method of manufacturing a print head, characterized in that the engagement surface of (6, 8) is surface-processed by electric discharge machining.