JPS62146648A - Serial printer head - Google Patents

Abstract

PURPOSE:To raise the attractive force of an armature and to obtain the small size printer head of high speed at low cost, by using permendur for the part extending inward in the radial direction of a yoke. CONSTITUTION:A printer head forms plural magnetic circuits in the peripheral direction at an interval and each magnetic circuit consists of the U-shaped yoke 3 existing in a plane perpendicular to the arranging direction of the magnetic circuit, a permanent magnet piece 4, the auxiliary yoke 5 extending inward in the radial direction, an armature 6, etc. Permendur of 50% Co, 48% Fe, and 2% V is used for an auxiliary yoke 5. When a coil 11 is in a demagnetized state, the armature 6 is magnetically attracted to the crest part of an inside leg part 8 against the spring force of a plate spring 14 caused by the magnetic force of the permanent magnet piece 4. When the coil 11 is magnetically excited, the magnetic path demagnetizing the magnetic force caused by the permanent magnet piece 4 is formed and the armature 6 is energized in the direction becoming more distant from the inside leg part 8 of the yoke 3. Then, a printing wire 2 strikes the ribbon on a platen to perform the printing operation on a recording paper.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention provides a printing wire based on control of electromagnetic force. This invention relates to a serial printer head for printing.

BACKGROUND TECHNOLOGY The conventional magnetic circuit of a serial printer head is
As shown in FIG. 5 and FIG.
Hit the magnetic force? It is composed of a coil 11 that is excited at a rate of 1'ft, an armature 6 that is urged toward or away from the yoke 3 by demagnetizing and excitation of the coil 1, and a printing wire 2 that is fixed to one end of the armature 6. be done. By energizing the coil 11, the magnetic force of the permanent magnet piece 4 is canceled, and the armature 6 is separated from the yoke 3, thereby displacing and driving the tip of the printing wire 2 to perform the printing operation (
You can do it. As for the performance of such a dot printer head, the drive speed of the printing wire, which affects the printing speed of the printer, is important, and it has been desired to improve this speed.

Therefore, in order to increase the speed of the printer head, it is necessary to lower the overall magnetic resistance in terms of the magnetic circuit and increase the attractive force by 7 times. However, since the magnetic resistance is particularly large in the part of the pair of guide pieces 13 of the auxiliary yoke 32, which is indicated by the reference numeral 5a in FIG. Therefore, the suction power of the armature 34 did not increase. Therefore, as a means to lower the magnetic resistance, there is a method of increasing the cross-sectional area of that part or using a material with high magnetic permeability. The former method has a problem in that the size of the head becomes larger, although this is contrary to the miniaturization of the printer head. In addition, the latter method includes, for example,
There is a prior art technique disclosed in Japanese Patent No. 0-87062, which uses permenole throughout the yoke. However, since a magnetic material with high magnetic permeability such as permendur is expensive, there is a drawback that the overall cost is high.

Purpose An object of the present invention is to solve the above-mentioned technical problems and to provide a serial printer head that is small, high-speed, and low-cost while increasing the suction force of the armature.

Embodiment FIG. 1 is a partial cross-sectional view of a dot-type serial printer head 1 of the present invention, and FIG. 2 is a simplified cross-sectional view taken along the section line 1--2 in FIG.

The basic structure of FIGS. 1 and 2 is similar to that of FIGS. 1 and 5, and corresponding parts are given the same reference numerals. This printer head 1 is configured such that a plurality of magnetic circuits 1a are formed at intervals in the circumferential direction, and a printing wire 2 is provided in association with each magnetic circuit 1.
Each magnetic circuit 1a basically includes a U-shaped yoke 3 located in a plane perpendicular to the arrangement direction of the magnetic circuits 1a, a permanent magnet piece 4, an auxiliary yoke 5 extending radially inward, and a printed It is composed of an armature 6 equipped with a wire 2 and the like.

The yoke 3 includes a cylindrical outer leg 7, a plurality of inner legs 8 formed radially inward than the outer leg 21S7 and arranged at intervals in the circumferential direction, and the outer leg 7. and a connecting part 9 extending between the inner leg part 8 and the inner leg part 8. Coils 11 are wound around the outer peripheral surfaces of the inner leg portions 8, respectively.

A flat ring-shaped permanent magnet piece 4 is fixed to the upper end surface of the outer leg portion 7 of the yoke 3. This permanent magnet piece 4 is magnetized in the vertical direction in FIG.
Form a magnetic path shown by . A ring-shaped auxiliary yoke 5 is fixed to the surface of the permanent magnet piece 4 opposite to the surface fixed to the yoke 3. The auxiliary yoke 5 has an arm portion 12 that extends radially inward, and a pair of guide pieces 13 that individually correspond to the inner leg portions 8 of the yoke 3 are formed at the distal end of the arm portion 12. be done. This guide piece 13 is
They are formed facing directly above the inner leg portions 8, respectively. Inside the guide piece 13, an armature 6 having a printing wire 2 is located at f.
be present. The armature 6 is arranged directly above the inner leg portion 8 of the yoke 3.

A retaining groove 15 is formed at one end of the armature 6, and the retaining groove 15 engages with one end of the leaf spring 14, and the end portions of the leaf spring 14 are fixed 77 to the top of the auxiliary yoke 5, respectively.

The material of the auxiliary yoke 5 includes a magnetic material with high magnetic permeability,
For example, in this embodiment, permendur as a Co (cobalt)-Fe (iron)--vananium alloy is used, and vernon-dur with 0050%, Fe48%, and 2% is used. On the other hand, the outer leg 7 of the yoke 3, the inner leg 8, the connecting part 9, and the auxiliary yoke 5
For this purpose, a material such as so-called 3% silicon steel containing 3% Si (silicon) in Fe is used.

As described above, the pernondule used only for the auxiliary yoke 5 has a very high magnetic permeability and a high saturation point of magnetic flux density B compared to 3% silicon steel used for the other yokes 3 and the like. Therefore, the area or volume required to pass a certain amount of magnetic flux Φ (winter clothes in Figure 2) at a certain magnetomotive force U is 3
% silicon. Therefore, by using permenole as the material for the auxiliary yoke 5, even if there is a portion 5a with a small cross-sectional area, such as near the guide piece 13 of the auxiliary yoke 5, the suction force of the amatia 6 can be reduced by 1. In addition, the equivalent mass of the movable parts of the present serial printer head can be reduced, and therefore, the speed of the printing wire 2 can be increased. However, the guide piece 13 of the auxiliary yoke 5 has a smaller cross section perpendicular to its axis and a smaller overall volume, so the amount of permendur used is also smaller, making it possible to achieve higher speeds and lower costs.

To explain the operating state of the serial printer head according to the present invention, first, what is the fill 11? 11f When in the magnetic state, it acts in the direction shown by the arrow a generated between the gap between the armature 6 and the yoke 4 (the magnetic flux of the permanent magnet piece 4 resists the spring force of the leaf spring 14). The amathia G is magnetically attracted to the top of the inner leg 8. In this state, the printing wire 2 is separated from the ribbon (not shown) of the platen.

On the other hand, when the coil 11 is excited, a magnetic path is formed in the direction indicated by the arrow, which cancels out the magnetic force of the permanent magnet piece 4. When the magnetic force by the permanent magnet piece 4 is canceled out in this way, the armature 6 is spring-biased by the spring force of the leaf spring 14 in the direction away from the inner leg portion 8 of the yoke 3. At this time, the armature 6 is bent in the direction shown by arrow A using the leaf spring 14 as a fulcrum, and as a result, the printing wire 2
hits the ribbon on the platen to print on the recording paper on the platen.

The fjS3 diagram shows the magnetic circuit 1a of the serial printer head.
FIG. This magnetic circuit 1a includes a permanent magnet piece 4 having a magnetomotive force UO1 and a resistance RM, a yoke 3 having a magnetic resistance R1,
The auxiliary yoke 5 of magnetoresistive R4, the armature 6 of magnetoresistive R3, the gap G of magnetoresistive RG, and the fill 11 of magnetoresistive force in1 magnetoresistive R2 are connected in series. Therefore, by using permendur with high magnetic permeability only in the auxiliary yoke 5 that is most likely to reach the saturated state among the yokes 3, the overall magnetic resistance R1 to R4 is reduced, and as a result, the yokes other than the auxiliary yoke 5 The suction force of the armature 6 can be increased without using permendur in each part such as 3. This makes it possible to realize a small, high-speed serial printer head. Furthermore, the cost can be significantly lower than when permendur is used for the entire yoke.

Effects As described above, according to the present invention, by using permendur in the radially inwardly extending portion of the yoke, the suction force of 7 gussets can be increased, and the yoke can be compact and high-speed. Moreover, a low-cost printer head can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a plan view of the vicinity of the guide piece 13 in FIG. 1, FIG. 3 is an equivalent circuit diagram of the serial head, and FIGS. 4 and 5 are FIG. 2 is a diagram for explaining a prior art. DESCRIPTION OF SYMBOLS 1... Serial printer head, 1a... Magnetic circuit, 2... Printing wire, 3... Yoke, 4... Permanent magnet piece, 5... Auxiliary yoke, 6... Armature, 7・
...Outer leg, 8...Inner leg, 11...Coil agent Patent attorney Keiichi Saikyo Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claim] A serial printer head configured by forming a plurality of magnetic circuits at intervals in the circumferential direction, and each magnetic circuit is provided with a printing wire in association with the magnetic circuit, wherein each of the magnetic circuits is permanently attached. 1. A serial printer head comprising a magnet piece and a yoke disposed in a plane perpendicular to the direction in which the magnetic circuits are arranged, and a portion of the yoke extending radially inward is made of permendur.