JPH0345352A - impact dot head - Google Patents

Abstract

PURPOSE:To uniformize the restoring force of an armature to obtain a uniform printing quality by a method wherein a depth of a restoring spring loading hole of a restoring spring holder is varied in accordance with a bending amount of each printing wire. CONSTITUTION:With a pulse conduction to a coil 17, a magnetic attraction force is generated between an armature 19, and a core 12, and the armature 19 is accelerated to start a rotating motion about a fulcrum part 19a in a direction of an arrow A. With this motion, a printing wire 8 is projected to come into collision with a printing medium to form a dot thereon. After the impact, a restitution force at the impact and the spring force of a restoring spring 16 make the armature 19 start a restoring action. After coming into collision with a damper 20, the armature 19 is held, and one printing process is completed. At this time, a depth H of a hole part 15d of a restoring holder 15 for loading the restoring spring 16 therein is determined so that the restoring force of the armature 19 is made constant in accordance with a force of rotating the armature 19 caused by the bending of the printing wire 8. Therefore, printing forces by all the printing wires 8 are uniformized so as to obtain a uniform printing quality.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an impact dot head for an impact printer.

[Conventional technology]

Conventionally, this type of impact dot head has had a wire arrangement as shown in FIG. Printing wire 308
The engaging portions of the armature 319 were arranged equally divided around the circumference, and were arranged in such a way that they were arranged in a straight line at the tip of the wire. In addition, as shown in FIG. 4, the armature 31
9 is held in a standby state by the spring force of a return spring 316, and the printing wire 308 is bent and supported by a plurality of wire guides 307.

[Problem to be solved by the invention]

However, in such a horizontal direction, since the bending amount ΔY of the wire in FIGS. 3 and 4 is different, the bending moment M of the wire applied to the armature differs depending on the armature. This bending moment M gives a rotational force to the armature, so the holding force of the armature during standby (hereinafter referred to as return force) is the spring force of the return spring and the force that attempts to rotate the armature due to the bending moment M of the wire. It becomes peace. The spring force of the return spring is the same for each armature.
Since it is set to a certain value, the return force will differ depending on the armature. For this reason, the armature causes the printing force to be F4, which makes it impossible to obtain uniform printing quality.

As a countermeasure to this problem, there was a method of changing the angle of the wire attachment using the armature to achieve a uniform return force. or
There was also a method to obtain a uniform return force by changing the return spring specifications depending on the armature. However, these methods have the drawback of increasing the number of parts, significantly impairing assembly efficiency, and increasing assembly costs.

The present invention has been made to solve the above-mentioned problems, and provides an impact dot head that can provide uniform printing quality without increasing assembly costs.

[Means to solve the problem]

The present invention is characterized in that the return spring holding position of the holding member that holds the return spring is set for each armature.

[Operation] In the impact dot head configured as above,
The return spring force of the return spring can be set according to the force that attempts to rotate the armature due to the wire bending moment) for each wire.

Therefore, the restoring forces of all the armatures can be made equal, making it possible to obtain uniform printing quality.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a sectional view of an impact dot head showing an embodiment of the present invention. A plurality of cores 12 are erected on the frame 2, and a coil 17 is cut around the cores 12 to form an electromagnet. Each core 12 is on the bottom of frame 2.
Two through holes 13 are provided in each of the coils 17, and the terminal portions 17a of the coils 17 are conductively fixed to the substrate 10 via the insulating plate 9 by soldering. A yoke plate 3, a side yoke 4, and an armature holder 5 are laminated on the outer peripheral upper surface of the frame 2. An armature 19 is located opposite the core 12.
are arranged at equal intervals on the circumference, and the tip of the armature 19 and the engaging part of the printing wire 8 are fixed by brazing at positions equally divided on the circumference.

As shown in FIG. 3, the printing wire 8 is held by a tip guide 6 attached to the nose 1, a plurality of wire guides 7, and a back guide 14, and is arranged in a staggered arrangement in two vertical rows at the tip of the printing wire 8. be guided as such. Therefore, the amount of bending of the printing wire 8 is different for each armature 19. A return spring holder 15 is arranged at the center opening of the frame 2, and a perspective view of the return spring holder 15 is shown in FIG. A plurality of holes 15d are provided in the return spring boulder 15, and the depth H of the holes varies depending on the location. Hole 15 (1 has a return spring 16
is attached and presses the armature] 9 toward the damper 20. All the return springs 16 are made of the same parts. A plurality of grooves 15a provided in the return spring holder 15 position the armature 9 in the lateral direction, and the armature 19 is guided so as to be movable in the direction along the grooves 15a. Three convex portions 15b having a trapezoidal cross section provided on the return spring holder 15 function as guides when the armature holder 5 is pushed in. The two cylindrical convex portions 15c of the return spring holder 15 position the fulcrum presser spring 18 and the armature holder 5. The fulcrum portion 19a of the armature 19 is biased against two surfaces of the outer periphery of the frame 2 by a fulcrum presser spring 18 attached to the lever boulder 5, and is rotatably supported around the fulcrum portion 19a.

Next, the operation will be explained with reference to FIG. In the standby state, the armature 19 is held pressed against the damper 20 by the spring force of the return spring 16. When the coil 17 is energized in pulses, a magnetic attraction force is generated between the armature 19 and the core 12. The armature 19 is accelerated by this magnetic attraction force, and the fulcrum part 19 is accelerated in the direction of arrow A.
It starts rotating around a. Accordingly, the printing wire 8 protrudes and collides with a printing medium (not shown) to form a dot. After the collision, the repulsive force and return spring 16 at the time of collision
The armature 19 enters the return operation due to the spring force of
After colliding with the damper 20, it is held and one printing process is completed.

In the above-described printing process, the bending of the printing wire 8 is set differently for each armature 19, so the force exerted by the printing wire 8 to rotate the armature 19 is different for each armature. In this embodiment, the hole 1 for mounting the return spring 16 of the return spring holder 15 is
The hole depth H of 5d is set so that the return force of the armature 19 is constant in response to the force that attempts to rotate the armature 19 due to the bending of each printing wire 8. Therefore, the printing force by all printing wires 8 is uniform, and uniform printing quality can be obtained. In addition, uniform printing quality can be obtained by simply changing the hole depth H of the hole 15d into which the return spring 16 of the return spring holder 15 is attached, so the cost of parts and assembly will not increase. .

〔Effect of the invention〕

According to the present application, the depth of the hole in which the return spring of the return spring holder is attached is changed according to the amount of bending of each printing wire, so the return force of the armature is uniform and uniform. Print quality can be improved.

In addition, since the depth of the hole in the return spring holder for attaching the return spring is simply changed, it is possible to create a low-cost impact dot head.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an invac 1-dot head showing an embodiment of the present invention. FIG. 2 is a perspective view of a return spring holder showing an embodiment of the present invention. FIG. 3 is a schematic diagram showing a conventional wire arrangement. FIG. 4 is a plan view showing a conventional printing wire, armature, and return spring. 1... Nose 2... Frame 3... Yoke plate 4... Side yoke 5... Armature holder 6... Tip guide 7... Wire guide 8... Printing wire 9... Insulating plate 10... Board 12... Core 15... Return spring holder 16... Return spring 17... Coil 18... Fulcrum holding spring 19... Armature 20... Damper

Claims (1)

[Claims] A plurality of armatures to which printing wires are fixed, a plurality of coil springs that apply a restoring force to the armature, and a holding member that holds the coil springs are arranged, and a plurality of cores with coils wound around opposing parts of the armature are arranged. An impact dot head characterized in that a coil spring holding position of the holding member that holds the coil spring is set for each armature in the impact dot head arranged.