JPH0140682Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the structure of a print head for a wire printer.

In this type of print head, stress is concentrated in the leaf spring fixed to the print wire near the end of the armature to which it is fixed each time the print wire is moved. For this reason, in the past, in order to alleviate this stress in the leaf spring and avoid concentrated strain, for example, holes were provided in the areas where the stress was concentrated to disperse the stress. However, the provision of holes had the disadvantage of lowering the rigidity of that part.

The purpose of this invention is to provide a printing head that prevents intensive fatigue from occurring in the leaf spring, increases the rigidity of the actuator consisting of the leaf spring and armature, and shortens the contact time of the printing wire with the printing surface. We are trying to provide the following.

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In FIGS. 1 and 2a and 2b, a plurality of degaussing coils 1 are wound around each of a plurality of cores 3 protruding from a back yoke 2. In FIG. A ring-shaped permanent magnet 5, a spacer 6, and a plurality of leaf springs 7 are arranged and fixed in this order from the back yoke 2 side between the back yoke 2 and the front yoke 4, which are tightened by screws (not shown). The leaf spring 7 is provided with a protrusion 8 by bending in the thickness direction. A wire 9 is brazed to the free end side of the leaf spring 7, and an armature 10 is brazed to the corresponding portion of the core 3 with a brazing material 11, respectively, and the leaf spring 7 and the armature 10 constitute an actuator. . The protrusion 8 is formed from the free end side of the leaf spring 7 to the fixed side by sandwiching the end 10a of the armature 10 facing the fixed side of the leaf spring 7, that is, the inner peripheral surface of the front yoke 4. ing. Also,
A guide frame 12 for guiding the wire 9 is screwed onto the front yoke 4.

The operation of the above configuration will now be described.

When the degaussing coil 1 is not energized, the leaf spring 7 is displaced to be attracted to the core 3. Degaussing coil 1 that cancels the magnetic field of permanent magnet 5
When energized, the wire 9 is pushed out by the energy stored in the leaf spring 7 and printing is performed.
When the demagnetizing coil 1 is no longer energized, the leaf spring 7 is attracted to the core 3 and returns to its original state. This operation is selectively performed only on the necessary wires 9 depending on the shape of the characters to be printed.

At this time, in order to relieve stress concentration in the welded portion between the leaf spring 7 and the armature 10 near the end 10a of the armature 10 that faces the front yoke 4, the leaf spring near the end 10a is The leaf spring 7 is held between both edges of the leaf spring 7 by sandwiching the end 10a.
Since the protrusion 8 is bent from the free end side to the fixed side of the armature 10, the plate spring 7 near the end 10a of the armature 10 has a protrusion formed by bending as shown in FIGS. 2a and 2b. 8 is provided. This protrusion prevents deformation from concentrating on this portion, thereby preventing damage to the leaf spring 7 due to fatigue.
Moreover, since no holes are provided as in the conventional example, high rigidity can be obtained as is, and the contact time of the wire 9 with the printing surface can be shortened, making it possible to increase the printing speed. Furthermore, since the bent shape is used, this part does not have to be widened to increase rigidity, which prevents the print head from becoming larger as a whole.

Next, another embodiment of the present invention will be described with reference to FIGS. 3a and 3b. The difference in FIG. 3 from the previous embodiment is that the projection 13 is formed by punching out rather than bending, and the armature 10 is laser welded to the leaf spring 7, and 14 is the welded part. It is. A detailed description of the structure and operation in FIG. 3 will be omitted.

In this embodiment as well, the protrusion 1 is
3, the concentration of stress can be alleviated as in the case of the previous embodiment, and furthermore, high rigidity can be obtained, making it possible to cope with an increase in printing speed.

As detailed above, the print head of the present invention can avoid local fatigue concentration of the leaf spring 7, and
By increasing the rigidity of the actuator, it is possible to shorten the time during which the printing wire 9 contacts the printing surface, thereby making it possible to speed up the printing operation, which has a great practical effect.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a print head showing an embodiment of the present invention, Fig. 2a is an enlarged view of the leaf spring seen from the direction in which the armature is welded, Fig. 2b is a side view thereof, and Fig. 2b is a side view of the leaf spring. Figure a is an enlarged view of a leaf spring in another embodiment of the present invention, and figure b is a side view thereof. In the figure, 1 is a degaussing coil, 3 is a core, 5 is a permanent magnet, 7 is a leaf spring, 8 is a protrusion by bending, 9 is a wire, 10 is an armature, 10a is an end, 13
is a protrusion formed by stamping.

Claims (1)

[Claims for Utility Model Registration] 1 A plurality of electromagnets and each electromagnet is provided with a printing wire fixed to one end, an armature fixed to the corresponding part of the core of the electromagnet, and the other end In a printing head that selectively excites the electromagnet and drives a printing wire to perform printing, the plate spring is located near the end of the armature opposite to the other end of the plate spring. 1. A printing head characterized in that projections are provided on both sides of the print head, sandwiching the end portions and projecting in the thickness direction from one end to the other end. 2. The protrusion provided on the leaf spring is formed by bending both edges of the leaf spring in the vicinity of the end of the armature from one end to the other with the end sandwiched between them. The printing head according to claim 1 of the utility model registration claim. 3. The protrusion provided on the leaf spring is formed by punching both sides of the leaf spring in the vicinity of the end of the armature from one end to the other end while sandwiching the end. A printing head according to claim 1 of the utility model registration claim.