JPH0446928Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a printing head used in a wire dot printer, and particularly to a stopper structure for preventing the armature from falling off during the assembly process.

[Conventional technology]

FIG. 5 is a partially sectional side view showing the internal structure of a conventional dot printer print head.

As shown in the figure, the print head consists of a casing consisting of a front case 1 and a rear case 2, and a magnetic drive device housed within the casing. This magnetic drive device includes a yoke 3 having a substantially U-shaped cross section, a core 4 installed upright on the yoke 3, a coil 5 wound around the core 4, end faces of the yoke 3 and the core 4, and a rear case 2. a wire 7 connected to one end of the armature 6, and a return spring 8 inserted between one end of the armature 6 and the upper end of the yoke 3.
, a support spring 9 inserted between the other end of the armature 6 and the rear case 2 , a damper 10 fixed to the lower surface of the rear case 2 , and an armature mounted and fixed on the yoke 3 . It is composed of a guide 11.

As partially shown in FIG. 6, the armature guide 11 has a plurality of holding parts 11a corresponding to each armature 6, and these holding parts 11a are held by an annular peripheral wall 11b. They are connected together. And armature 6 is adjacent to 2
Since it is formed to be slightly narrower than each holding portion 11a, it is restricted in the circumferential direction and faces each core 4. Further, the gap (magnetic gap) between the armature 6 and the upper end of the core 4 is set to a predetermined dimension by the upper surface of the armature 6 coming into contact with the damper 10.

The print head configured as described above attracts the armature 6 with magnetic attraction force by energizing the coil 5, and by turning off the current, the armature 6 is attracted with the return force of the return spring 8 compressed during attraction. Wire 7 pushed back and connected to armature 6
The printer drives the printer to perform printing.

[Problem that the invention attempts to solve]

By the way, when assembling the printing head configured in this way, the armature 6 is inserted between each holding part 11a of the armature guide 11 via the return spring 8, and then the armature 6 is inserted into the upper end of the front case 1. By covering the rear case 2, the support spring 9 and the damper 10 are brought into contact with the upper end of the armature, and the armature 6 is positioned. Therefore, as shown in FIG. 7, in the middle of the assembly process, the armature 6 inserted into the armature guide 11 may be pushed back by the elastic force of the return spring 8 and come off from the armature guide 11, or There was an inconvenience that the wire 7 connected to the armature 6 came off from the wire guide 1a at the tip of the front case 1.

In order to prevent such inconvenience during assembly, the thickness of the armature guide 11 is increased to prevent the armature 6 from falling off from the armature guide 11, and the length of the wire 7 is made longer than necessary. If measures are taken to prevent the wire 7 from coming off the wire guide 1a, the former will unnecessarily increase the thickness of the armature guide 11, which will hinder the miniaturization of the print head, and the latter will prevent the wire 7 from coming off the wire guide 1a after assembly is completed. Since unnecessary portions of the wire 7 must be cut, a new drawback arises in that workability is poor.

SUMMARY OF THE INVENTION An object of the present invention is to provide a print head for a wire dot printer that eliminates the drawbacks of the prior art described above and can simplify assembly work.

[Means for solving problems]

To achieve this objective, in this invention, in order to prevent the armature from falling off during the process before installing the rear case, the armature is supported against a return spring by a part of the armature guide that is fixed to the core. It is characterized by the provision of a stopper with elastic force to prevent

〔Example〕

Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 1 is a sectional side view of a print head of a wire dot printer according to an embodiment of the present invention, and FIG. 2 is a plan view showing details of an armature guide provided in the print head. In FIG. 1, the yoke 3, core 4, coil 5, armature 6, wire 7, return spring 8, support spring 9, damper 10, etc. are shown in FIG. 6 and are the same as those in the conventional example described above. Explanation will be omitted.

The feature of this embodiment is particularly the structure of the armature guide 11 shown in FIG. That is, in this embodiment, armature guide holding portions 11a each having a slit 11d are provided on a peripheral wall 11b of an armature guide 11 made of synthetic resin and having a substantially disk shape so as to project toward the center. At approximately the tip of the movable piece 11e adjacent to the slit 11d, each stopper 11c is provided to protrude in the circumferential direction, and the length between each stopper 11c and the holding portion 11a is opposite to the stopper 11c. The width of the armature 6 is set smaller than the width of the armature 6.

The assembly process of the print head having the armature guide 11 constructed in this manner and the function of the stopper 11c will be explained in detail with reference mainly to FIGS. 3 and 4.

After placing and fixing the armature guide 11 on the yoke 3 in the same manner as before, the armature is moved between the respective holding parts 11a of the armature guide 11 against the return spring 8, as shown in FIG. Insert 6. At this time, since the movable piece 11e has elastic force, when the armature 6 is inserted, this armature 6
However, after insertion, it returns to its original position due to the elastic force of the armature 6, and the stopper 11c is brought into contact with the upper surface of the armature 6, and the return spring 8
The armature 6 is supported against the elastic force of (temporarily fixed state). Therefore, the armature 6 is stably supported by the armature guide 11 by having its rear end and center abut against the yoke 3 and the stopper 11c, respectively.
The distal end of the armature 6 to which the wires are connected does not lift up, and the wire 7 does not come off from the wire guide portion 1a once inserted.

After temporarily fixing each armature 6 to the armature guide 11 as described above, the rear case 2 is attached to the upper end of the front case 1 to complete the assembly. As shown in FIG. The support spring 9 and the damper 10 are in contact with each other, and the third
Armature 6 in the middle of the assembly process as shown in the figure
The contact between the armature 6 and the stopper 11c is released, and the magnetic gap between the armature 6 and the core 4 is closed to the damper 10.
Therefore, it is set to a predetermined dimension. The assembly work of the rear case 2 can be performed very easily since it can be performed with the armature 6 stably supported by the armature guide 11 as described above. Further, since it is not necessary to provide the wire 7 with an extra dimension to prevent it from coming off, there is no need to cut the wire 7 after assembly is completed.

[Effect of idea]

As explained above, according to the present invention, the inserted armature can be stably supported by the yoke and stopper during the assembly process before the rear case is attached, which has the remarkable effect of simplifying the assembly process. play.

[Brief explanation of drawings]

Figures 1 to 4 relate to an embodiment of the present invention, in which Figure 1 is a cross-sectional side view of the printing head, Figure 2 is a plan view of the armature guide, and Figure 3 is a state in the middle of the assembly process. 4 is a partial plan view of the printing head, FIGS. 5 to 7 are related to the conventional example, FIG. 5 is a partial sectional side view of the printing head, and FIG.
The figure is a partial plan view showing the relationship between the armature and the armature guide, and FIG. 7 is a partial sectional side view of the printing head in a state in the middle of the assembly process. 1...Front case, 2...Rear case, 3
... Yoke, 4 ... Core, 5 ... Coil, 6 ...
Armature, 7... Wire, 8... Return spring, 9... Support spring, 10... Damper, 11...
... Armature guide, 11a ... Holding part, 11
b... Peripheral wall, 11c... Stopper, 11d...
Slit, 11e...Movable piece.

Claims (1)

[Scope of utility model registration request] A plurality of wires, a plurality of armatures made of a magnetic material connected to the wires, a yoke, a core erected on the yoke and disposed opposite to the armature, and a core wound around the core. an elastic member that biases the armature in a direction away from the core; a rear case that is attached to the upper part of the armature; and a rear case that is fixed to the lower surface of the rear case and that the upper surface of the armature abuts. a damper for setting a gap between the armature and the upper end of the core to a predetermined size; and an armature guide placed between the armature and the rear case; In a printing head of a wire dot printer that drives the wire by suction in a direction, the armature has an elastic force that supports the armature after being inserted into a holding part provided in the armature guide against the elastic force of the elastic member. A wire dot printer printing head characterized by having a stopper section.