JPS6048336B2 - dot printer printer head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printer head for a dot printer.

First, a conventional example will be explained based on FIG. 1.

Reference numeral 1 denotes a platen, and a recording paper 2 and a printing ribbon 3 are provided on the front surface of the platen 1.

Reference numeral 4 denotes a head main body, which is not shown, but is held by a carrier that reciprocates along the platen 1.

The head body 4 has a flange portion 6 to which a support plate 5 is fixed at the center.
and a cylindrical portion 7 are integrally formed, and a yoke 8 is fixed to the flange portion 6. This yoke 8 includes a core 9 provided on the yoke 8 and a coil 1 inserted into the core 9.
0 and an armature 12 rotatably attached to the yoke 8 while being urged in the return direction by a spring 11. A plurality of electromagnets 13 are arranged and attached in a radial manner.
One end of the core 9 is a suction surface 14. The cards 15 and 16 provided on the support plate 5 and the cylindrical portion 7 have a return direction (
A needle 18 made of a wire biased by a spring 17 is inserted to the left. A metal fitting 19 that is struck by the armature 12 is fixed to the rear ends of these needles 18. Next, a cover 21 is fixed to the flange portion 6 of the head body 4 with a spacer 20 in between, and a stopper 22 made of an elastic member such as rubber is fixed to the inner surface of the cover 21.

Therefore, although a specific electromagnet 13 is energized during printing, high-speed printing cannot be performed unless the armature 12 and needle 18 bounce when they return.

In particular, when the needle 18 flies with a stroke greater than the stroke of the armature 12 due to the movement of the armature 12, the bounce of the needle 18 is large and there is a risk of double printing. Therefore, the shock when the armature 12 and needle 18 return is absorbed by the stopper 22 made of an elastic member. However, the mounting dimensions of the stopper 22 are inaccurate and the armature 1
2 The return position is incorrect and the stroke of the needle 18 is also incorrect. For this purpose, the position of the stopper 22 is adjusted by adjusting the thickness of the spacer 20. Furthermore, there is another conventional example shown in FIG.

That is, the head main body 23 consists of a flange portion 6 and a short cylindrical portion 24, and a yoke 8 in which a plurality of electromagnets 13 are arranged is attached to the flange portion 6 as shown in FIG. A long cylindrical needle guide 25 that holds the needle 18 that collides with the platen 1 by the operation of the armature 12 is fitted into the cylindrical portion 24 of the head body 23 so as to be slidable and fixed at any position with a screw 26. There is. A stopper 27 is connected to one end of the needle guide 25, and an elastic member such as rubber is fixed to the inner surface of the stopper 27. 29 is a leaf spring that biases the armature 12 in the return direction.

Therefore, the elastic member 28 prevents the armature 12 from bouncing, and the needle guide 25 and stopper 27 slide together to adjust the return position of the armature 12 and the stroke of the needle 18.

However, although the screw 26 can slide the needle guide 25 steplessly and lock it at any position, the area to be pressed is too small, and the shock during printing may cause the screw 26 to become misaligned, and the cylindrical portion 24 and the needle guide 25 may It is also difficult to assemble the shafts with their axes exactly aligned. This invention was made in view of the above-mentioned points, and an object of the present invention is to provide a printer head for a dot printer that can prevent the armature and needle from bouncing when they return, and can also make the stroke of the needle uniform and simplify assembly. It is something to do.

This invention provides an elastic member in the stopper body to absorb the shock when the armature and needle return to prevent bouncing, and the stopper body made of a hard member is attached to the head body to correct the position of the reference plane. By providing the elastic member with the abutting surface located in the same plane as the determined reference plane, the position of the abutting surface of the elastic member with the armature can be determined and the stroke of the needle can be made uniform, and the stopper The structure is such that the dimensions of the main body and the dimensions of the attachment position to the head main body can be easily managed, thereby eliminating the need for difficult adjustment work. An embodiment of the present invention will be described based on FIGS. 3 to 5.

Components that are the same as those described in FIG. 1 are designated by the same reference numerals, and description thereof will be omitted. A guide block 30 is fixed to a support plate 5 that is a part of the head body 4. This guide block 30 has a plurality of grooves 31 formed on the outer periphery of a cylindrical material made of metal, through which the tip of the armature 12 and the needle 18 are passed. Then, a leaf spring 33 having a plurality of legs 32 that contact the rear end of the armature 12 and urge the armature 12 in the return direction, and a stopper body 34 are fixed to the center of the guide block 30 by a screw 35. installed on.

This stopper main body 34 is formed of a hard member such as metal. An irregularly shaped reference surface 36 is formed on one surface of the stopper body 34 and serves as a mounting surface to the end surface of the portion of the return guide block 30 where the groove 31 is not formed, and at least the tip of the armature 12. An elastic member 37 made of rubber or the like is embedded in a portion facing the. The contact surface 38 of the elastic member 37 with respect to the armature 12 and the reference surface 36 are made to coincide with each other. In such a configuration, when a specific electromagnet 13 is energized for a very short time during printing, the armature 12 is attracted to the suction surface 14 against the force of the leaf spring 33 and hits the metal fitting 19 of the needle 18.

The needle 18 is moved against the armature 12 against the force of the spring 17.
It flies with a stroke greater than , and collides with the platen 1. The armature 12 is a leaf spring 33
The needle 18 first returns due to the force of the spring 17 and collides with the elastic member 37, and the needle 18 returns later due to the force of the spring 17 and collides with the armature 12, but the shock caused by these collision forces is absorbed by the elastic member 37. Therefore, it is possible to prevent the armature 12 and needle 18 from bouncing, and there is no fear of double printing or ghost printing. Since the stopper body 34 is made of a hard member such as metal, the reference plane 3 can be adjusted by determining the length of the guide block 30.
6 can be accurately positioned with respect to the suction surface 14 together with the position of the contact surface 38 of the elastic member 37. Thereby, the return position of the armature 12 (the gap between the armature 12 and the suction surface 14) and the stroke of the needle 18 can be made constant, and the troublesome stroke adjustment can be eliminated. Although the stopper body 34 was indirectly fixed to the support plate 5, which is a part of the head body 4, with the guide block 30 in between, the stopper body 3
A mounting portion fixed to the support plate 5 may be integrally formed on the reference surface 36 of 4. That is, depending on the shape of the stopper body, it may be attached directly to the head body 4. Since this invention is configured as described above, the elastic member provided on the stopper body absorbs the shock when the armature and needle return to prevent bouncing, thereby eliminating the possibility of double printing or ghost printing. You can also
By providing an elastic member on the stopper body made of a hard member and setting the contact surface of the elastic member to the armature and the reference plane of the stopper body in the same plane, it is possible to simply determine the mounting dimensions of the stopper body to the head body. This has the advantage that the position of the elastic member can be determined by simple means, the return position of the armature and the stroke of the needle can be made uniform, and troublesome stroke adjustment can be omitted.

[Brief explanation of the drawing]

Figures 1 and 2 are horizontal sectional views showing a conventional example, Figure 3 is a horizontal sectional view showing an embodiment of the present invention, Figure 4 is a perspective view of a guide block, and Figure 5 is a stopper body and elastic It is a perspective view of a member. 1...Platen, 4...Head body, 8...
・Yoke, 12... Armature, 13... Electromagnet, 14... Suction surface, 18... Needle, 34...
Stopper body, 36... Reference surface, 37... Elastic member, 38... Contact surface.

Claims (1)

[Claims] 1. A yoke provided with a plurality of electromagnets each having an armature biased in the return direction is attached to the head body that moves back and forth along the platen, and a plurality of needles are moved toward the platen by the operation of the armature. and directly or indirectly attaching a stopper body made of a hard member such as metal to the head body, the reference surface facing the return side surface of the armature being positioned with respect to the suction surface of the electromagnet; A printer head for a dot printer, characterized in that the stopper body is provided with an elastic member that comes into contact with the return side surface of the armature, with the surface that makes contact with the armature located in the same plane as the reference surface.