JPS587373A - Wire dot type printing head - Google Patents

Abstract

PURPOSE:To resttain a strsas from acting on a welded point and prevent a spring from being broken by a method wherein the welding point between an armature and the spring is set near the central point of the impact force of the armature. CONSTITUTION:The welding point a' between the armature 8, driven magnetically by a magnet, and the spring 6 supporting the armature is coincided with the central point C of the impact force of the printing wire 10 and both of them are fixed. According to this method, loads will not be concentrated on the welded point a' and the shock thereof is absorbed near the lowest end of the armature 8, thus, the spring 6 may keep a long life. If a distance from the fixed end e of the spring 6 to the welded point a', that means the length of the spring, is shorter than a distance 12 to the central point C of the impact, the life of the spring may be shortened remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wire dot type printing device widely used as an input/output device in an information processing device.

Conventionally, as shown in FIG. 1, this type of print head has been disposed inside a magnet (1), which has one surface entirely covered and bonded to a cylindrical magnet (1) which is magnetized by VCM in the height direction. A coil 4 is wound around each core 3. A ring 5 of a magnetic member having seven screw holes is attached to the other cylindrical end surface of the magnet 1 . The uncontacted end surface of the ring 5 and the tip of the core 3 [fi (the other surface of Mi) are substantially on opposite sides. Spring 6 on top of ring 5
There is a thin ring-shaped gap spacer for determining the fixed end of the spring 6 and setting the gap between the spring 6 and the core 3, and the spring 6 is placed on this gap spacer. The spring 6 has a spring 7 that protrudes radially toward the center.
It is made by integrating individual leaf springs. A rigid armature 8 made of a magnetic member is fixed to the free end side of each divided leaf spring of the spring 6 at welding points a and b. A yoke 9 made of magnetic material and shaped to cover the side surface of this armature is placed on top of the spring 6. A printing wire 10 is fixed to the armature 8 at its upper end. Furthermore, a wire guide frame 11 is arranged above the print wire 9, and the seven printing wires 10 are converged and arranged in a row with their free ends (recording medium striking ends). Wire guide frame 11. York 9,
The spring 6 and the gap spacer 7 are fastened to the ring 5 with seven screws 12.

The print head configured like a runner performs a printing operation as follows. Normally, the area armature 8 is attracted to the core 3 by the magnetic flux generated from the magnet 1, and the thin plate-shaped spring 6 is bent. When a current is applied to the coil 4 in a direction that cancels the magnetic flux of the magnet 1, the magnetic attraction force between the armature 8 and the core 3 is released, and the armature 8 moves in the direction of arrow A due to the restoring force of the spring 6, and the printing wire 10
to strike the recording medium. When the current supply to the coil 4 is stopped, the archiere 8 is attracted to the core 3 again by the magnetic absorption force of the magnet 1. By repeating such operations, predetermined characters and symbols are printed on the recording medium. In the process of this printing operation, the impact force when the printing wire 10 hits the recording medium is the armature 8.
Welding part a#bK is added. As a result, the armature 8 rotates in the direction of the arrow X around the center point C of the rigid body's constricting force. This impact force center point C is not affected by the impact force from the printing wire IO, but the area around the center point C is subjected to impact force. Therefore, as shown in FIG. 2, in the print head formed by resistance welding the armature 8 and spring 6 at points a and b, stress is concentrated at the weld point a, which is farther from the print wire 10. During the relatively short printing operation period, the spring 6 will break near the welding point a as shown in the figure d.

An object of the present invention is to set the welding point between the armature and the spring near the center of the impact force of the armature, which is a single cape, to suppress breakage of the spring due to stress acting on the welding point. The purpose is to provide the head.

The wire dot type print head according to the present invention includes a thin plate spring that is magnetically driven to contact and separate from the core, a rigid armature that is welded to the spring at multiple locations, and one end that is fixed to the armature. And note @
A printing wire whose other end that strikes the medium is convergently arranged, and a welding fixing point of the spring and the armature that is far from the printing wire is near the center point of the impact force of the armature. shall be.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 3 is a diagram showing the relationship between the distance to the armature welding point and the distance to the armature welding point. Spring 6 and armature 8 are at the center of impact C
When resistance welding is performed at points a and b on both sides of It changes completely.

The welding point farthest from the printing wire 10 is located at a distance of /1 from the spring fixed end e, and the load is concentrated near this point, causing the spring 6 to break. On the other hand, if the spring 6 and the cape cheer 8 are fixed with the welding point al aligned with the center point C of the impact force as shown in FIG. The load is not concentrated and is buffered near the lowermost end of the armature 8, so that the spring 6 maintains a long life. As shown in FIG. 3(c), if the distance from the fixed end C of the spring 6 to the welding point a1, that is, the length of the spring, is shorter than the distance 12 to the center point C of the impact, its life will be significantly shortened.

In such a print head where an impact force is applied to the button printing wire, a long life of the spring can be maintained by welding near the center point of the impact force of the rigid body.

As explained above, the present invention is based on the fact that the welding point between the armature to which the printing wire is attached and the thin plate spring is located at the center point of the shock of the rigid armature, which is farther away from the wire. This prevents excessive force from being applied to the welding point and ensures the long-term printing action of the spring.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a cross-sectional view showing an example of a printing head according to the present invention, Fig. 2 is a perspective view showing a conventional movable part configuration of the print head shown in Fig. 1, and Fig. 3 (a) to FIG. 3(c) are diagrams illustrating an embodiment of the present invention. 1: McNet 2: McNet Pace 3: Core
4: Coil 5: Ring 6: Suffling 7: Gear, lath spacer - 8 near gusset 9: Yoke 10: Printing wire 11: Wire guide frame 1
2: Screw a # a' a k): Welding point C:
center of force

Claims (1)

[Claims] A thin plate spring that is magnetically driven to contact and separate from the core, a rigid armature that is welded and fixed to this spring at multiple locations, and one end that is fixed to this armature and is used to strike a recording medium. A wire dot type print head comprising a printing wire whose ends are convergently arranged, and wherein a welding fixation point of the spring and the armature farthest from the printing wire is near a center point of impact force of the armature.