JPH05309846A - Printing head of wire dot type - Google Patents

Abstract

PURPOSE:To ease the effect of magnetic interference on a drive wire that is caused when a wire in which magnetic fluxes in different directions flow is driven at half-timing, in a clapper type printing head where the direction of a magnetmotive force generated by a coil is reversed alternately between pairs of armatures. CONSTITUTION:In a clapper type printing head in which the direction of a magnetmotive force generated by a coil is reversed alternately between pairs of armatures, a side magnetic arm 13, made of a magnetic material, is provided between adjacent armatures 5 whose magnetic flux directions are the same, but is not provided between adjacent armatures 5 whose magnetic flux directions are opposite to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clapper type wire dot type print head for forming characters by dot matrix for printing.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, a clapper type wire dot type print head of this type has a side magnetic arm 13 made of a magnetic material between all adjacent armatures 5.

[0003]

In the above-mentioned conventional clapper type wire dot type print head, the directions of the magnetic fluxes passing through the armatures are alternately reversed by two, and the magnetic fluxes between all adjacent armatures are reversed. It had a side magnetic arm. FIG. 4 shows a magnetic flux waveform at the time of half-timing drive. The dotted line in the figure shows the operation state when the conventional print head is driven at a half timing with a wire through which a magnetic flux in the opposite direction to the drive wire flows. .. In this way, when the armature in which the magnetic flux flows in the opposite direction to the driving armature is driven at half timing, the magnetic flux that had decreased decreases sharply under the influence of magnetic interference, and the return of the armature deteriorates. Was causing the problem.

[0004]

SUMMARY OF THE INVENTION The present invention is an armature,
A magnetic path is formed by a yoke and a ring yoke, and in a clapper-type wire dot print head in which the directions of the magnetomotive forces generated by the coils wound around the inner yoke are alternately reversed, the directions of the magnetic flux are the same. A side magnetic arm made of a magnetic material is provided between adjacent armatures, and the side magnetic arm is not provided between adjacent armatures whose magnetic flux directions are reversed.

[0005]

The present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing a relationship between a side magnetic arm and an armature according to an embodiment of the present invention, and FIG. 2 is a sectional view showing a configuration of the embodiment of the present invention.

In this embodiment, the coil 2 is incorporated around the inner yoke 1 and the outer yoke 3
A ring yoke 4 is provided on the upper side, and an armature 5 and an armature support 6 for holding the armature 5 are provided on the ring yoke 4. Armature 5
The direction of the magnetic flux passing through is alternately reversed by two. A side magnetic arm 13 made of a magnetic material is provided between the adjacent armatures 5 having the same magnetic flux direction,
Armature 5 adjacent but reversing the direction of magnetic flux
The side magnetic arm 13 is not provided between them. The armature support 6 incorporates a return spring 7 that assists the armature 5 in returning. The print wire 8 is fixed to the tip of the armature 5,
Above the fulcrum of the armature 5, there is a support rubber 9 that returns the armature 5 centered from the normal position to the normal position. Further, there is a rear cover 10 thereon, and the support rubber 9 is pressed toward the armature 5 side to hold the armature 5 in a regular position. A guide 12 for arranging the print wires 8 in a predetermined matrix is housed in the nose of the head frame 11.

FIG. 4A is an explanatory diagram of half timing, and FIG. 4B is a diagram showing a magnetic flux waveform. The solid line indicates the case where there is no other timing half-driving for the drive wire, and the dotted line indicates the case where the conventional print head is driven at half timing for the wire in which the magnetic flux in the opposite direction to the drive wire flows.

Next, the operation of the entire print head of this embodiment will be described. The armature 5 is stationary while being pressed against the rear cover 10 by the return force of the return spring 7. When the coil 2 is energized, the armature 5 is attracted to the suction surface side of the inner yoke 1,
Printing is performed with the tips of the print wires 8 arranged in a matrix. The print head of this embodiment is an armature 5
The side magnetic arm 13 is provided only between the armatures 5 in which the direction of the magnetic flux passing through is the same, and the side magnetic arm 13 is not provided between the armatures 5 in which the direction of the magnetic flux is reversed. Even if the other wires are driven at half timing, it is possible to mitigate the phenomenon that the magnetic flux that is decreasing, which is generated in the conventional print head, rapidly increases due to the wraparound of the magnetic flux from the other wires. As shown in (b), the reduction of magnetic flux is smoothed, and the printed wire 8
The operation of can be stabilized.

[0009]

As described above, according to the present invention, in the clapper type wire dot type print head, the magnetic flux passing through the armature has a side magnetic arm between adjacent armatures in the same direction, and the magnetic flux direction is Does not have a side magnetic arm between adjacent armatures in opposite directions,
Even if the armature in which magnetic fluxes in different directions flow is driven at half timing with respect to the driving armature, the wraparound of the magnetic flux can be alleviated, the magnetic flux can be smoothly reduced, and the operation of the armature can be stabilized.

[Brief description of drawings]

FIG. 1 is a plan view showing a relationship between a side magnetic arm and an armature according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the configuration of an example of the present invention.

FIG. 3 is a plan view showing an armature portion of a conventional print head.

FIG. 4A is an explanatory diagram of half timing, and FIG. 4B is a diagram comparing magnetic flux waveforms of the present invention and a conventional example.

[Explanation of symbols]

 1 Inner yoke 2 Coil 3 Outer yoke 4 Ring yoke 5 Armature 6 Armature support 7 Return spring 8 Print wire 8 Support rubber 10 Rear cover 11 Head frame 12 Guide 13 Side magnetic arm

Claims (1)

[Claims] 1. A clapper type wire dot type print head in which a magnetic path is formed by an armature, a yoke and a ring yoke, and the directions of magnetomotive forces generated by a coil wound on an inner yoke are alternately reversed by two. The magnetic flux has the same direction and a side magnetic arm made of a magnetic material is provided between adjacent armatures, and the side magnetic arm is not provided between the armatures which are adjacent but have opposite magnetic flux directions. Wire dot type print head.