JPS60174660A - Printing head for dot printer - Google Patents

Abstract

PURPOSE:To achieve the lowering of release current, by a method wherein the shape of outer peripheral yoke constituting a magnetic circuit is made to be the unified type core which is jointly held as the movable part fitting part and the magnetic leakage part for lowering of demagnetizing current. CONSTITUTION:The outer peripheral part 12 constituting a magnetic circuit is made to be the unified type core which is jointly held as the magnetic leakage part 13 for lowering of demagnetizing current and the movable part fitting part 14, which is jointly held as the magnetic leakage part 13, and by making the magnetic leakage part 13, the movable part fitting part 14 and the yoke 11 be so constructed as to be opposed in the circumferential direction, magnetic leakage (a) is generated in the circumferential direction. By such a constitution, the surface area of yoke 11 through which magnetic flux can be leaked from the yoke 11 to the outer peripheral yoke 12 is kept down small and the leakage magnetic flux (b) from the yoke 11 to the outer peripheral yoke 12 having a different electrode is lowered. Then, the breaking current can be lowered without spoiling the inner magnetic type magnetic circuit for the purpose of achieving the rise of attracting force.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention uses a print head used in a dot-type wire printer, and in particular, prints characters such as kanji at high speed and with high precision using a large number of arranged printing wires. The present invention relates to a print head for a dot printer configured to print.

Structure of conventional examples and their problems In recent years, advances in computers and peripheral technology have led to advances in information processing using computers, and in the field of office automation, there has been an increase in kanji information processing that takes advantage of the characteristics of Japanese that are easy to read and understand. Needs are increasing. Along with this, various printers are being developed, and among these printers, wire dot printers that can print on various types of paper and are inexpensive are rapidly developing. Therefore, a wire dot type print head for Kanji printers in which a plurality of printing wires and drive elements are arranged has been developed as a print head for dot printers, and measures such as higher speed, smaller size, and lower noise are desired.

A conventional print head for a dot printer will be explained below.

FIG. 1 is a simplified cross-sectional view of a print head for a conventional dot printer.

First, using Figure 1, 3.
− Describe the structure of the print head. In Figure 1, 1
is a permanent magnet, and an upper yoke 2a and a lower yoke 2b are bonded to both end surfaces thereof. 2C is a yoke integrated with the upper yoke 2a, and 2d is a pole integrated with the lower yoke 2b. 3 is an armature installed in the magnetic circuit gap 4 formed by the yoke 2C and the pole 2d.

This armature 3 is fixed via a driving leaf spring 5, and a printing wire 6 is attached to the other end of the armature 3, forming a printing wire movable section. 7
8 is a leaf spring holder, and 8 is a degaussing coil wound around the outer circumference of the pole 2d.

The operating principle of the printing gutter configured as described above will be explained.

This print head employs a spring-charge type print wire drive system, and includes a print wire movable section consisting of an armature 3 and a driving plate spring 5, and a permanent magnet 1. It consists of a magnetic circuit section consisting of an upper yoke 2a, a lower yaw 2b, a yoke 2c, a pole 2d, and a degaussing coil 8, and the armature 3 installed in the magnetic gap 4 is normally attracted to the pole 2d by the magnetic field of the permanent magnet 1. being attracted. In this state, the driving leaf spring 5 is in a bent state and accumulates elastic energy. Then, in response to the print signal, a current is passed through the degaussing coil 8 wound around the outer circumference of the pole 2d in the direction of canceling the magnetic field, thereby canceling the attractive force of the permanent magnet 1 and releasing the elastic energy of the driving leaf spring 5. The printing wire 6 protrudes from the guide surface. At this time, the ink on the ink ribbon is transferred to the printing paper by the impact of the printing wire, and the color develops in dots. Next, when the current to the degaussing coil 8 is cut off, the armature 3 is attracted again by the attractive force of the permanent magnet 1, and the printing wire 6 is returned to its original position. With the above operations, one dot cycle is completed.

The structure and operating principles of the conventional print head for dot printers have been described above. Next, the advantages and disadvantages of the above-described print head will be described below.

As an advantage, since the elastic energy of the driving leaf spring 5 is used as printing energy, the mark 5 zoom character energy can be mechanically set and easily controlled.

Further, when the printing wire 6 starts to move, the spring 6 is at its maximum deflection, so that the maximum acceleration force can be obtained. Furthermore, since the permanent magnet 1 is used to attract the armature 3, the armature 3 is attracted by the permanent magnet 1 when the printing wire 6 returns, so there is an advantage that so-called chattering (double striking due to the armature bounce phenomenon) is reduced. There is. Because of this, high printing quality and high speed printing are possible, and the above-mentioned spring-charged printing wire drive system is currently frequently used as a printing head for dot printers.

In addition, when attempting to further increase the speed of the print head using the above method, it is necessary to increase the force of the magnetic circuit consisting of the permanent magnet, yoke, and degaussing coil to increase the printing speed by increasing the attractive force. There is.

However, in the case of the current magnetic circuit for a print head, the opposing area of two yokes with different magnetic poles is large, so magnetic leakage increases, and even if the force of the magnetic circuit section is increased by 6t, I can't hope to improve the suction power,
There was a problem in that it was difficult to increase the printing speed. In addition, when trying to downsize the print head, using the conventional magnetic circuit structure, the permanent magnet 1
Because it is attached to the outer yoke, it becomes large and difficult to downsize, and if the outer circumference is made smaller,
The permanent magnet 1 has also become smaller, and in the conventional structure, the attractive force has been significantly reduced.

Therefore, as a means to solve the above problem, a magnetic circuit has been proposed in which the attractive force is improved by using a magnetic circuit shape as shown in FIG.

The conventional magnetic circuit shape shown in FIG. 2 will be explained below. The difference between FIG. 2 and FIG. 1 is that the integral yoke 9 has the same magnetic pole on the outer circumferential yoke in order to reduce leakage magnetic flux, and the permanent magnet 1o attached to the inner circumferential surface of the integral yoke 9 has the same magnetic pole on the other side. The yoke 11 was attached.

With this configuration, it is possible to suppress the product of the surface 7 of the yoke 110 that may leak from the yoke 11 to the outer yoke 9, thereby reducing the leakage magnetic flux from the yoke 11 to the outer yoke 9 with different magnetic poles. However, in the case of a print head using the above-mentioned magnetic circuit, the current required to flow through the degaussing coil 8 (hereinafter referred to as the opening current) in order to open the driving leaf spring 5 is the same as that of the permanent magnet 1o.
Since the area of the two yokes (outer yoke 9 and yoke 11) facing each other via the yoke is small, the permanent magnet 1
When viewed from the perspective of an electromagnetic circuit designed to demagnetize zero energy, a large current is required. Therefore, the drive current flowing through the degaussing coil 8 becomes a large current, which causes problems such as heat generation due to Joule heat and the need for an electronic circuit with a large capacity capable of supplying a large current.

OBJECT OF THE INVENTION The present invention solves the above-mentioned conventional problems by changing the shape of the outer circumferential yoke constituting the magnetic circuit to an integrated core that serves as a movable part and a magnetic leakage part for reducing degaussing current. The object of the present invention is to provide a print head for a dot printer which can reduce open circuit current and print characters at high speed and with high precision.

Structure of the Invention In order to achieve the above object, the present invention provides a yoke which is provided with a permanent magnet at the end of the inner circumferential surface of the outer circumferential yoke, which has the same magnetic pole as the pole around which the degaussing coil is wound, and which faces the pole. , an armature that is drivably provided in a magnetic gap between the pole and the yoke, and a movable part mounting part to which a movable part having the armature is attached to the inner peripheral surface of the outer peripheral yoke. , the movable part is attached with a magnetic leak part that faces the yoke in the circumferential direction to form an integrated core, and thereby the two outer circumferential yokes and the yoke with different magnetic poles are connected to each other. Since the area where leakage can occur can be reduced, the open circuit current can be reduced, making it possible to increase the speed of the print head, and also to reduce the number of parts and production costs.

FIG. 3 is a simplified structural sectional view showing the shape of the magnetic circuit of a print head for a do//) printer in an embodiment of the present invention.

The difference between FIG. 3 and FIG. 2 is that the outer circumferential yoke 12 constituting the magnetic circuit is an integrated core that serves as a magnetic leak part 13 for reducing degaussing current and a movable part mounting part 14. The leak part 13 and the movable part are attached so that the part 14 and the yoke 11 face each other in the circumferential direction, so that magnetic leakage a occurs in the circumferential direction.

Magnetic leakage a caused by this configuration
is essentially different from the leakage magnetic flux, and the leakage magnetic flux can be suppressed as small as possible, thereby improving the attractive force. Further, the magnetic leakage a reduces the opening current required to cause a current to flow through the degaussing coil 8 to open the driving leaf spring 5 and cancel the energy of the permanent magnet 10. Here, if the amount of magnetic leakage a becomes too large, the attractive force characteristics of the magnetic circuit will deteriorate;
' The optimum amount of magnetic leakage is set by adjusting the distances 11 and 12 between the parts 14.

FIG. 4 is a diagram showing the relationship between the number of simultaneously printed dots and the open circuit current in this embodiment. In FIG. 4, the dotted line C shows the characteristics of this embodiment, and the solid line d shows the conventional characteristics.

In this way, according to this embodiment, the surface area of the yoke 11 that can leak from the yoke 11 to the outer yoke 12 is suppressed to a small level,
The leakage magnetic flux from the yoke 11 to the outer yoke 12 with different magnetic poles is reduced, and the open current is reduced without impairing the effect of the inner magnetic type magnetic circuit that improves the attractive force. By forming the part 14 into an integral structure that also serves as the outer circumferential yoke 12, it is possible to reduce the number of parts and, in turn, to reduce production costs.

The outer yoke of the magnetic circuit, which is designed to face the magnetic circuit, has an integral core with a movable part attachment section and a magnetic leakage section for reducing degaussing current, thereby reducing magnetic leakage 11,... The opening current required to flow through the degaussing coil to open the leaf spring is small, without impairing the effect of the internal magnet type magnetic circuit, which aims to reduce the magnetic field and improve the attractive force, thereby improving the demagnetizing characteristics. This makes it possible to increase the speed of the print head, and since the movable part is attached to a structure that also functions as an outer yoke, the number of parts can be reduced, which in turn reduces production costs. It is also possible to do this, and the effect is a dog.

[Brief explanation of drawings]

1 and 2 are simplified cross-sectional views of the print head for a conventional dot printer, FIG. 3 is a cross-sectional view of the simple structure of a print head for a dot printer according to an embodiment of the present invention, and FIG. 4 is a cross-sectional view of the simple structure of a print head for a dot printer according to an embodiment of the present invention. FIG. 3 is a diagram showing the relationship between the current characteristics and the open current characteristics. 2d... Paul, 3... Amateur,
5...Driving plate spring, 8...Demagnetizing coil, 10...Permanent magnet, 11...Yoke, 12...Outer yoke , 13... Magnetic leak part, 14... Number of moving parts is indicated.

Claims (1)

[Claims] A yoke is provided at the end of the inner peripheral surface of an outer yoke having the same magnetic pole as the ball around which the degaussing coil is wound, via a permanent magnet, and facing the ball, and can be driven into the magnetic gap between the ball and the yoke. a movable part mounting part for attaching a movable part having an armature to the inner circumferential surface of the outer peripheral yoke; 1. A print head for a dot printer, characterized in that an integrated core is formed by providing magnetic leak portions facing each other in directions.