JPS62236754A - Wire dot head - Google Patents

Abstract

PURPOSE:To miniaturize the whole of the titled device and to reduce the abrasion of a wire, by setting the cross-sectional shape of a magnet element for protruding a wire to an almost equilateral triangle and providing a guide member guiding the wire so as to allow the same to pass on the bisector of the vertical angle thereof. CONSTITUTION:The bisectors of a coil bobbin 17 and the hole 20c of an auxiliary yoke 20 respectively coincide with the bisector 40 at the vertical angle of a coil core having an almost equilateral triangle shape and the wire guide hole 23b of a sub-body 24 is arranged on the extension line of said bisectors so as to become longitudinal and, further, the longitudinal guide hole 13a of an intermediate guide 13 is also set on the extension line of the bisectors so as to become a longitudinal shape and two circular arc rows. Further, the guide hole 12a of the intermediate guide 12 has an almost out-of-roundness shape and is guided in a state of two straight line rows almost the same to a leading end guide 11.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention comprises a plurality of magnet elements formed by winding a coil around a magnetic member, arranged in a ring shape, and a rocking device provided corresponding to each magnet element. This invention relates to a wire dot head in which a lever is swung by its magnetic force and a wire provided corresponding to each oscillating lever is projected.

(Prior Art) In recent years, wire dot heads have shown a trend toward higher printing quality by increasing the number of wires, and the heads themselves have also become larger accordingly. As the head becomes larger, the weight increases, and the load on the motor that moves the head to the left or right increases, thus requiring a motor with higher torque.

At the same time, the motor itself is thick, so a large power supply is required each time, which directly leads to an increase in cost.It is no exaggeration to say that the wire dot head is what influences the overall price of the printer.

Therefore, it is conceivable to make the solenoid for driving the wire into a trapezoidal shape or the like, increase the mounting density of the solenoid, and downsize the entire head.

(Problems to be Solved by the Invention) When the solenoid is made into a trapezoidal shape as described above, the packaging density certainly increases. However, the mounting position of the armature lever attracted by this solenoid is regulated by its magnetic efficiency, which makes it difficult to guide the wire at the tip of the armature, which tends to cause wear between the wire and the guide.

(Means for Solving the Problems) The cross-sectional shape of the magnet element for protruding the wire is approximately an isosceles triangle, and a guide portion for guiding the wire to pass is provided on the bisector of the apex angle.

(Example) The basic structure and operation of an example of the wire dot head of the present invention will be explained below with reference to the attached drawings.

Fig. 1 is a front view of the wire dot head, Fig. 2 is a side view thereof, Fig. 3 is a rear view thereof, Fig. 4 is a plan view thereof, and Fig. 5 is a sectional view taken along line A-A in Fig. 1. FIG. 6 and FIG. 7 are views of the rear surfaces in the order of assembly in the direction of FIG. 3, and FIG. 8 is an exploded perspective view. In FIG. 1, reference numeral 1 denotes a front cover, which is made of die-cast aluminum, has radiation fins 2, and has a U-groove 1a for fixing to the main body with screws. The front cover 1 is fixed to the yoke 4 with screws 3.

On the back side of this yoke 4, a rear cover 5 made of a material with high heat dissipation such as aluminum is attached with screws 6.
It is fixed at . After this, the cover 5 is provided with heat radiation fins 7 as shown in FIG.

As shown in FIG. 5, the front cover 1 includes a recess 1b, a groove 1c, and a groove 1c for installing guides that support the wire 10.
ld is provided, a distal guide 11° groove portion 1c is provided in the recess lb, and an intermediate guide 12. 13 is fitted and fixed. The tip guide 11 is an important member that affects printing quality, and must have excellent abrasion resistance.In this print head, glass ceramic is used, and 1 to 2
Coated with μ titanium nitride. Since this print head is an 18-pin print head, this tip guide 1
1 has two rows of 9 holes arranged in a staggered manner, and the wire diameter is 0.25 mm, so the guide hole diameter is 0.
．． It is 27mm.

The intermediate guides 12 and 13 are also important members for stabilizing the behavior of the wire 10, and are made of a mold in this print head. Reference numeral 4 denotes a cup-shaped yoke, which is an important member in the magnetic circuit, and is made of 3% silicon steel with excellent magnetic properties.It is precision-coated with 18 coil cores 14 arranged in a ring inside the cylindrical wall 4a. It is integrally formed by casting, and the outer cylindrical wall 4a of the yoke 4 and the end surface of the core 14 are on the same plane. Furthermore, the cylindrical wall 4a of the yoke 4 has a shape that also serves as a heat dissipation fin, and the surface of the yoke 4 is coated with black electrodeposition to improve the dielectric strength around the core 14 and heat dissipation. The surface in contact with the cover 1, the surface in contact with a spacer 15 to be described later, and the end surface of the core 14 are polished after electrodeposition coating.
It is then nickel plated to ensure electrical continuity throughout the print head. A bobbin 17 wound with a copper wire 16 is inserted into the core 14, and two terminals 18 are attached to the bobbin 17.
These two terminals are individually press-fitted and have a plate shape, and the copper wire 1
The beginning and end of winding No. 6 are soldered. Furthermore, bobbin 1
7 is made of PBT containing 10% glass fiber, which has excellent heat resistance. This terminal 18 is soldered to a flexible cable 19, and a copper wire 16 is connected to the flexible cable 19.
It has the role of supplying current to. A spacer 15 made of pure iron is placed on top of the yoke 4, and a disk-shaped auxiliary yoke 20 is placed on top of the spacer 15.

Eighteen posts 21 are press-fitted into the auxiliary yoke 20, and a molded subbody 24 is integrally formed by outsert molding. This subbody 24 holds the armature return spring 22 in the hole 24a,
It also guides the armature lever (swinging lever) 23, which will be described later, and further supports the base of the wire IO brazed to the armature lever 23 by the oval guide hole 24b, and the armature lever 23 and the inner edge 24
Abutting at point c defines the forward position of the wire.

The auxiliary yoke 20 is a member constituting a magnetic circuit,
It is made of pure iron, and the post 21 is made of nitride stainless steel with excellent wear resistance. A shield film 25, which is a ring-shaped film with holes that fit into the 18 posts 21, is installed on the auxiliary yoke into which the 18 posts 21 are press-fitted, and is made of polyimide with excellent wear resistance. Become. An armature lever 23 is installed on the shield film 25, a movable core 26 is integrated with the armature lever 23 by caulking, and a wire 10 is attached to one end.
is fixed by brazing, and there is a post 2 on the other end.
There is a hole that fits into 1. The armature lever 23 is made of a highly rigid SK material to ensure stable operation, and the movable core 26 is made of pure iron because it is an important member constituting the magnetic circuit. Here, the magnetic circuit is the coil core 14. York 4. Spacer 15° Auxiliary yoke 20
．． The movable core 26 forms a closed magnetic path.

That is, when the copper wire 16 is energized, a magnetomotive force is generated, and the movable core 26, which is the movable part of the closed magnetic circuit, is attracted in the direction of the coil core 14, so the armature lever 23 rotates about the fitting part with the post 21 as a fulcrum. Then, the wire IO fixed to the armature lever 23 moves in the direction of the page (not shown) to print a dot, and after printing, the armature return spring 2 returns to the standby state.
Return by 2.

The stop portion at the time of return is the stopper 27. This stopper is made of rubber and is integrated with the stopper fitting 28 by baking. Print head internal temperature from OoC to 120
℃, the stopper 27 is made of an elastic material that has excellent heat resistance and low rebound resilience, which affects the stability of the operation of the wire 10. In addition, the rubber thickness is made thin (0.2 mm) in order to minimize the temperature dependence of the stopper's rebound resilience.On the other hand, the stopper metal fitting 28 is a vibration damper to suppress the impact noise generated when the stopper 27 and the armature lever 23 collide. The stroke of the wire 10 in the backward direction is controlled by the stopper 27.
Since the stroke adjustment washer 29 is interposed between the sub-body 21 of the molded part of the auxiliary yoke 20, the stroke can be adjusted in units of 0.02 mm. This stroke adjustment washer is made of phosphor bronze. The stroke film 3 is placed on the amateur lever 23.
0 is installed, and the armature lever 23 is pressed by the armature presser spring 31 from above, and the armature lever 23 rotates about the post 21. amateur presser spring 3
1 is made of stainless steel, and if the armature lever 23 comes into direct contact with the armature lever 23, the armature lever 23 will wear out, so the stroke film 30 has a function to prevent this. On the other hand, the amateur lever 23 and the stopper 27 are
Since it is made of rubber, it tends to stick and may cause printing defects, so a stroke film 30 is interposed between the armature lever 23 and the stopper 27 to prevent this. In this way, the stroke film 30 includes protection against wear of the armature lever 23 by the armature presser spring 31;
It also has two functions to prevent printing defects due to adhesion between the armature lever 23 and the stopper 27.

The amateur presser spring 31 is connected to the stopper fitting 28 and the damper 3.
2, and is fixed to the subbody 24 with a screw 33 via a damper 32. This damper 32 is made of zinc, which has high vibration damping properties, in order to suppress the impact noise generated when the armature lever 23 collides with the stopper 27. Furthermore, a damper presser spring 34 made of stainless steel is installed on top of the damper 32, and presses the damper 32 with an appropriate pressing force, and the pressing force at the main print head is approximately 3.6 kg.
It is. Further, as shown in Fig. 3-4, this damper pressing spring 33 is held down by an aluminum rear cover 5, and the auxiliary yoke 20.
It is fixed to the yoke 4 with four screws 6 via a spacer 15. After this, the cover 5 is also painted black to improve heat dissipation. Furthermore, the yoke 4 has a parallel pin 35.
are press-fitted into the core 14 of the yoke 4 and the spacer 12. The positional relationship between the auxiliary yoke 20 and the rear cover 5 is accurately defined.

Since this print head has a large temperature rise, in order to protect the copper wire 16, a thermistor 36 is embedded in a portion of the yoke 4 with a silicone adhesive having high thermal conductivity.

Further, as shown in FIG. 1, the front cover 1 is positioned with parallel pins 37 and fixed to the yoke 4 with four screws 3 in order to properly position the wires 10 and guides. The flexible cable 19 that supplies current to the print head is bent in the middle, and in order to protect this flexible cable 19, a flexible cable presser 38 (No. 2.3
), and this cable presser 38 is
It is fixed to the yoke 4 with a book (Fig. 8).

Further, in this embodiment, as clearly shown in FIG. 6, the cross-sectional shape of the coil core 14, the cross-sectional shape of the bobbin 17,
The shape of the hole 20c provided in the portion of the auxiliary yoke 13 corresponding to the coil core 14 is approximately an isosceles triangle. Such a triangular shape is reasonable in terms of compactness by mounting the coil core centrally, but in this example, the magnetic field generated by the coil core 14 and the copper wire 16 can be used efficiently. In order to guide the wire effortlessly and smoothly and prevent wear, the orientation of the coil core, etc., and the orientation of the wire's kite hole, etc., are carefully considered. That is, as shown in the figure, the bisector 40 of the apex angle of the approximately isosceles triangular coil core 14 coincides with the bisector 40 of the hole 20c of the coil bobbin 17 and the auxiliary yoke 20. Subbody 2 so that it becomes longitudinal on the extension line of the branch line
Four guide holes 24b are arranged, and the longitudinal kite holes 13a of the intermediate kite 13 are also set to be longitudinal on an extension of the bisector, and to form two arcuate rows.

The guide holes 12a of the intermediate guide 12 have a substantially perfect circular shape, and are guided in substantially the same two straight lines as the tip guide 11.

With the wire 10 guiding structure as described above, each wire is guided approximately on the bisector of the apex angle of each coil core, and the sliding resistance of the wire is minimized. In addition, since the center line of the armature lever 23 coincides with this bisector, the magnetic flux emitted from the coil core 14 passes through the armature lever 23 most efficiently, and the magnetic field generated by the copper wire 17 is efficiently absorbed. Can be used.

Next, the principle of printing using the wire 10 will be described in detail.

A bobbin assembly in which copper wire 16 is wound around a bobbin 17 is inserted into the coil core 14 which is a part of the yoke 4, and the yoke 4
A spacer 15 is installed on the end face of the spacer 15, an auxiliary yoke 20 is installed on the spacer 15, and a movable core 26 is installed on the auxiliary yoke 20.
A hole 20c is provided for the purpose, and a post 21 is press-fitted into one part. On the other hand, a wire lO is fixed to the tip of the armature lever 23 by brazing, a movable core 26 is integrated with the armature lever 23 by caulking approximately in the center thereof, and a post 21 is attached to the other end of the armature lever 23.
A hole is provided for the amateur lever 23 to be attached to the post 21.
The post 21 is rotated by using the post 21 as a fulcrum. When the copper wire 16 is energized, a magnetomotive force is generated, and the resulting magnetic flux is directed to the core 14.
゜Yoke 4. Spacer 15. It passes through the auxiliary yoke 20 and the movable core 26 to form a closed magnetic path. At this time, coil core 1
4 and the movable core 26, the movable core 26 is attracted toward the core 14, and as a result, the wire IO operates to perform printing.

(Effects) As described above, in the present invention, the cross-sectional shape of the magnet element for protruding the wire is approximately an isosceles triangle, and a guide member is provided to guide the wire so that it passes on the bisector of the apex angle. Therefore, it is possible to provide a wire dot head that can be miniaturized as a whole, has a high magnetic effect rate, and has less wire wear.

[Brief explanation of drawings]

FIG. 1 is a front view of a wire dot head according to an embodiment of the present invention, FIG. 2 is a side view of the head, FIG. 3 is a rear view of the head, FIG. 4 is a plan view of the head, and FIG. 1, FIGS. 6 and 7 are explanatory views showing the back surface of the head in the order of assembly, and FIG. 8 is an exploded perspective view of the entire head. ■・・・・・・・・・・・・・・・・・・Front cover 4・・・・・・・・・・・・・・・・・・ Yoke 5...・・・・・・・・・・・・・・・・・・Rear cover 10・・・・・・・・・・・・・・・・・・・・・
・Wire 11・・・・・・・・・・・・・・・
・Tip guide 12, 13・・・・・・・・・・・・
Intermediate guide 14-・・・・・・・・・・・・・・・
・・・・・・ Coil core 15・・・・・・・・・・・・・・・
・・・・・・・・・ Spacer 16・・・・・・・・・
・・・・・・・・・・・・Copper wire 17・・・・・・・・・・
・・・・・・・・・・・・ Bobbin 20・・・・・・・・・
・・・・・・・・・・・・・ Auxiliary yoke 21・・・・
・・・・・・・・・・・・・・・・・・ Post 22...
・・・・・・・・・・・・・・・・・・ Return spring 2
3・・・・・・・・・・・・・・・・Amateur lever 26・・・・・・・・・・・・・・・・・・Movable core 27・・・・・・・・・・・・・・・・・・・ Stopper 31・・・・・・・・・・・・・・・・・・ Amateur presser spring 32・・・・・・・・・・・・・・・・
...Damper man 1 figure Shooting 2 figure Rei 30 Item LL figure μ

Claims (2)

[Claims] (1) A plurality of magnet elements made by winding a coil around a magnetic member are arranged in a ring shape, and a swing lever provided corresponding to each magnet element is swung by its magnetic force to correspond to each swing lever. In the wire dot head, the cross-sectional shape of the magnet element is approximately an isosceles triangle, and the apex angles thereof are arranged to face the center, and each half of the apex angle is A wire dot head characterized in that a guide portion is provided for guiding the corresponding wire to pass along the line. (2) The guide portion has a plurality of oval guide holes for guiding each wire, and these guide holes are arranged with their longitudinal directions aligned on the bisector of each of the magnet elements. A wire dot head according to claim 1, characterized in that: