JPS6282051A - Apparatus for driving printing element - Google Patents

Abstract

PURPOSE:To enhance the cooling effect of a coil generating heat, by a method wherein a permanent magnet is provided at a central part and front and rear yokes are provided so as to hold the permanent magnet therebetween while a plurality of iron cores are arranged on the outer peripheral part of the permanent magnet to be fixed to the rear yoke and a coil is wound around each iron core. CONSTITUTION:An adhesive is injected into the recessed part 16a provided at the central part of the front surface of a yoke 16 and a permanent magnet 15 is mounted in said recessed part 16a to be fixed thereto. A coil terminal plate 19 is arranged at the front surface of the rear yoke 16 while a coil 20 is engaged with the iron core 18 fixed to the rear yoke 16. A front yoke 14 is located and mounted by a locating pin 17 so that the permanent magnet 15 is positioned at the central part of the rear yoke 16 and an adhesive is injected from a through-hole 14b to fix the permanent magnet 15. Three locating pins 22 are inserted in the front yoke 14 under pressure so as to be directed forwardly and the locating hole 12c of a spacer 12, the locating hole 9a of a drive spring 9 and the locating hole 8c of a stopper 8 are engaged with the locating pins 22 to successively stack the spacer 12, the drive spring 9 and the stopper plate 8 and the locating holes 1g of a head frame are engaged with the locating pins 22. Because the outside of the coil is opened, cooling effect is high and adaptation to high speed printing is enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a driving device for a printing element in a dot-type printer such as a Tosoto Matrix printer that represents characters, symbols, etc. with a number of rows of dots. .

(Prior art) In the prior art, for example, as shown in Japanese Unexamined Patent Publication No. 55-154178, a yoke is fixed to the front and rear of a donut-shaped permanent magnet, and a plurality of iron cores are installed in the space inside the permanent magnet. Some coils are arranged with a coil and a plurality of coils wound around the coil.

(Problems to be Solved by the Invention) In the above conventional technology, since the coil is located in a confined space, when the coil generates heat due to current flowing through the coil during driving, the heat is trapped in the space. It stays indoors and has problems dissipating heat. This problem of heat dissipation becomes particularly serious when high-speed printing is intended.

Therefore, an object of the present invention is to enhance the cooling effect of the heat generated by the coil.

(Means for Solving Problems) A feature of the present invention is that a permanent magnet is provided in the center, a front yoke and a rear yoke are provided in front and behind the permanent magnet, and a 1M number of magnets are provided on the outer periphery of the permanent magnet. Placing an iron core?゛? A coil is wound around each core, and a plurality of drive hammers that drive a plurality of printing elements are driven by this number of stages of cores and fills.

(Function) The iron core and coil are placed on the outer periphery of the permanent magnet.
Since the coil is not confined and is located in an open space,
The heat generated by the coil during operation is dissipated into the container.

(Example) In FIGS. 1 and 2, a head frame 1 is integrally molded from synthetic resin such as carphone graphite, and constitutes a support portion for a printing element.

That is, the head frame 1 is provided with a hollow portion 1a, and a window 1b is opened in the front surface. A plurality of step portions 1c, ld, le, and if are formed at predetermined intervals in the depth direction on at least the opposing inner walls of the hollow portion 1a. Guide plates 2, 3, and 4°5 are arranged at predetermined intervals within the hollow portion 1a. As shown in Figures 3 to 6, each guide plate 2 to 5 has guide holes 2a, 3a, 4a, etc. for guiding a plurality of printing wires 6, which are examples of printing elements.・、
5a... is provided. The side edges of the guide plates 2, 3, 4, and 5 have stepped portions lc, ld, le, 1. Positioning surfaces 2b, 3b, 4b, and 5b that can come into contact with the surface f are provided. Further, spacer pieces 3c, 4c, 5c extending from the guide plates 3, 4.5 toward the adjacent guide plates are provided to protrude forward in this example. The spacer piece may be provided so as to protrude rearwardly, or may be protruded forwardly and rearwardly,
Each end face may be provided so as to be in contact with the end faces of adjacent spacer pieces. Of the guide plates 2.3 and 4.5, the guide plate 2 at the tip is provided with a protrusion 2d that protrudes forward and fits into the window 1b, and this protrusion 2d is provided with guide holes 2a... . A printing wire 6 is placed in the recess on the back side of the guide plate 5.
The rear end protrudes, and a spring 7 returns to each wire 6.
- is fitted and fixed to the rear end of each wire 6 printing bottle 6a
It is impossible to fall off due to...

When assembling, make sure that the hollow part 1. Insert the tip guide plate 2 through the lower opening of the window a, push it forward, and insert the protrusion 2d into the window 1.
b to bring the positioning member 2b into contact with the stepped portion IC. Next, the guide plate 3 is inserted through the lower opening and pushed forward to bring the positioning surface 3b into contact with the stepped portion 1d. The guide plate 4 is similarly inserted into the hollow portion 1a, and its positioning surface 4b is brought into contact with the stepped portion 1e. Note that the guide plates 2°3.4 may be inserted sequentially from the back of the head frame 1 to the front. The guide plate 5 is inserted from the back side of the head frame 1, and its positioning member 5b is brought into contact with the stepped portion 1f. After that, each printing wire 6 is returned to fit the spring 7, and each printing wire 6 is inserted into the guide hole 5a at a predetermined position from the back side of the guide plate 5.

Insert into 4a, 3a, 2a. The tip of each wire 6 is located in the guide hole a, and when the rear end surface of each printing pin 6a is pushed, the return spring 7 is compressed and projected to print.

A driving section for printing wires 6 is provided on the back side of the head frame 1. That is, as shown in Figure 1.2, a stopper plate 8. is attached to the back of the head frame 1. Drive spring 9
．． Spacers 12 are stacked one on top of the other. Drive spring 9
As shown in FIG. 7, the arm 9a is
. . . are provided in a number equal to the number of printing wires 6 . . . (12 in this example). A driving hammer 10 is attached to the intermediate portion of each arm 9a. Drive hammer 10
The tip of the arm 9a extends closer to the center than the tip of the arm 9a, and the rear end is located in the middle of the arm 9a.
They overlap from the middle part to the tip of a. The tip of the arm 9a is spot welded to the drive hammer 10 to increase its rigidity. A movable yoke 11 is attached to the middle part of the arm 9a, and in this example, the movable yoke 11 passes through the overlapping driving hammer 10 and the arm 9a.
1 is connected by caulking. The end surface of each marking pin 6a of the printing element 6 is brought into elastic contact with the front surface of the tip of the driving hammer 10 by the spring force of the return spring 7. The movable yoke 11 is driven by an electromagnet device 13, which will be described later.

The stopper plate 8 is provided with stopper pieces 8a extending toward the center within the gap between the drive hammers 10. Both sides of the stopper piece 8a are provided with an engagement surface 9 of the arm between the tip of the arm 9a and the rear end of the drive hammer 10, which is created by making the drive hammer 10 narrow and the arm 9a wide.
It overlaps with the front of b.... From the middle to the outer circumference of the arm 9a, the collar plate 8 overlaps the drive spring 9.

The movable yoke 11 is normally attracted by an electromagnetic device 13, which will be described later, and the spring section outward from the middle section of the arm 9a is flexibly bent and displaced rearward, and the tip of the drive hammer 10 is in the retreated position. For this reason, the printing wire 6 is retracted by the return spring 7, and its tip does not protrude from the head frame 1. During printing, the magnetic field that had been attracting the movable yoke 11 is canceled out, so that the movable yoke 11 becomes free and moves forward by the spring force of the drive spring 9. Since the arm 9a overlaps with the drive hammer 10 from the middle part to the tip, its rigidity is increased, so the forward force of the arm 9a is reliably transmitted to the drive hammer 10, and the tip of the drive hammer 10 moves forward, and the printing wire Advance 6. When the arm 9a moves forward, the arm 9a gradually comes into contact with the stopper plate 8 from its outer periphery toward the distal end, and its return is stopped when the engagement surface 9b finally comes into contact with the stopper piece 8a. When two members that are separated from each other momentarily collide and stop, a loud impact sound is emitted at the time of stopping, but this occurs because the contact area gradually increases continuously from the outer periphery of the arm 9a. The impact noise is extremely small.

The electromagnet device 13 that drives the 11J moving yoke 11 will be described. A front yoke 14 is superimposed behind the spacer 12. As shown in the first figure, the front yoke 14 is provided with a through hole 14a into which the movable yoke 11 is loosely fitted. A permanent magnet 15 is provided at the center of the back surface of the front yoke 14, and a rear yoke 16 is provided at the back surface of the permanent magnet 15. 1st.
8 As shown in the figure, there are three positioning pins 1 on the front yoke 14.
7 is press-fitted, and this pin positions the permanent magnet 15 at the center position. Also, adhesive is injected through the through hole 14b provided in the center of the front yoke 14, and the permanent magnet 15
is fixed at the center position. A number of stages of iron cores 18 are located on the outer periphery of the permanent magnet 15 and are fixed to the rear yoke 16. Each iron core 18 faces each movable yoke 11 at its front end surface.

The coil terminal plate 19 has a donut shape, and the iron core 18
A plurality of through holes 19a are provided through which the holes 19a can be penetrated. A coil 20 is fixed concentrically to the front surface of the through hole 19a. Terminal pins 21 are fixed to the outside of the coil 20 and pass through the coil terminal plate 19. Both ends of each coil 20 are connected to the end of each terminal pin 21 projecting forward from the coil terminal plate 19, thereby forming a coil assembly.

When assembling, remove the four parts 16 at the front center of the rear yoke 16.
Adhesive is injected into a, and the permanent magnet 15 is placed and fixed. Next, the coil terminal plate 19 is disposed on the front surface of the rear yoke 16 while the coils 20 are fitted to the iron cores 18 that are fixed to the rear yoke 16. Next, the front yoke 14 is positioned and placed so that the permanent magnet 15 is located in the center using the positioning pin 17, and the permanent magnet 15 is fixed by injecting an adhesive through the through hole 14b. Three positioning pins 22 (shown in Figure 1.10) are press-fitted into the front yoke 14 toward the front. Therefore, the positioning hole 12c of the spacer 12 and the positioning hole 9c of the drive spring 9 are attached to the positioning pin 22.
, the positioning holes 8c (shown in FIG. 7) of the stopper plate 8 are fitted, and the printing wires 6 are successively overlapped, and then the positioning holes 1g of the head frame 1, which supports the printing wires 6, are fitted as described above.

Finally, screw in the fixing screws 23 from the front side of the head frame 1 toward the front yoke 14 to complete the assembly.

Note that each terminal pin 21 is connected to a predetermined position of a flat cable (not shown) on the back side. Further, a heat dissipation fin (not shown) is provided on the outer periphery surrounding the 1M coils 20.

(Effects of the Invention) In the present invention, which improves this configuration, the coil is located in a confined space, and the outside of the coil is open, so that the heat generated by the coil during driving is easily transferred to the outside. is emitted,
It has a great cooling effect and can be applied to high-speed printing. The cooling effect can be further enhanced by arranging the radiation fins close to the outside of the coil.

[Brief explanation of drawings]

Figure 1 is a longitudinal cross-sectional view, Figure 2 is a cross-sectional view taken along the line ■-■ in Figure 1, Figures 3 to 6 are enlarged front views showing guide plates, and Figure 7 is a cross-sectional view taken along the line ■-■ in Figure 1. 8 is a sectional view taken along the line ■--■ in FIG. 1, FIG. 9 is a partially cutaway sectional view taken along the line IX--IX in FIG. 1, and FIG. 10 is a rear view. 6... Printing element (printing wire), 10... Drive hammer, 14... Front yoke, 15
...Permanent magnet, 16...Rear yoke, 18...Iron core, 20...
·coil. that's all

Claims (1)

[Claims] A permanent magnet located at the center, a front yoke and a rear yoke located front and rear with this permanent magnet in between, and a permanent magnet located at the outer periphery of the permanent magnet and fixed to the rear yoke. , a printing element driving device comprising a plurality of iron cores for driving a plurality of driving hammers that drive a plurality of printing elements, and a coil wound around each of the iron cores.