JPH0226865B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a print head of an impact type printer, and in particular, a large number of print wires are connected to the print head in a portion facing the printing paper perpendicular to the running direction. The present invention relates to a printing head in which electromagnetic mechanisms for driving these printing wires are arranged in a staggered manner in the direction of printing and are arranged adjacently in a circumferential manner.

[Conventional technology]

Conventionally, the print heads of impact printers are generally of the so-called electromagnet-driven type, in which the strain energy of a spring member acts as printing force by releasing the attractive force of the electromagnet, and the so-called electromagnet-driven type, which uses reverse excitation of the electromagnet. There is a so-called cancel type type in which the strain energy of a spring member acts as a printing force by canceling the attractive force of a permanent magnet.

In recent years, cancel type print heads have been widely used. In this type of cancelled-type print head, adjacent electromagnets may be driven simultaneously. In this case, a problem arises in that the operation of the printing element becomes unstable due to magnetic interference between the electromagnets.

One way to improve this problem is to
The more electromagnets that are driven simultaneously, the more electrical energy must be input into the electromagnets.

For this reason, the printing wires are arranged in two rows, and the distance between these rows is set to 1/2 an integral multiple of the dot pitch that makes up the character.
In order to reduce magnetic interference, the number of printing wires that are driven at the same time is halved by arranging the printing wires at a value that is equal to the dot pitch.

[Problem to be solved by the invention]

By arranging the print wire as described above, magnetic interference when driving the print wire is reduced to some extent. Incidentally, the print head of this type of printer is required to print at increasingly high speed and high definition, and it is important to further reduce the influence of magnetic interference. Furthermore, as printing speeds increase, reducing noise during printing is also becoming an important issue.

It is an object of the present invention to provide a printhead that can reduce magnetic interference and noise.

[Means to solve the problem]

In the present invention, a large number of printing wires are arranged in a staggered manner in a direction perpendicular to the running direction of the printing head in a portion facing the printing paper, and these printing wires and a large number of electromagnetic mechanisms that drive them are arranged in a circumferential manner. In the printing head arranged adjacently above, the printing wire and the electromagnetic mechanism are divided into even-numbered groups of 4 or more, and the spacing between each adjacent group in the running direction of the printing head is such that the character at the tip of the printing wire is 1/2 to an integral multiple of the dot pitch that makes up
In addition, in the above groups, the distance in the printing head running direction between each group at opposing positions was set to a value that is an integral multiple of the dot pitch at the tip of the printing wire. It is characterized by

[Effect]

First, a large number of printing wires and electromagnetic mechanisms are divided into even-numbered groups of 4 or more, and the spacing between adjacent groups in the printing head running direction is set to 1/2 dot pitch, which is an integral multiple of the dot pitch constituting a character. Since adjacent groups are not driven simultaneously, the frequency of magnetic interference can be reduced.

Furthermore, since the printing wires between the groups at opposing positions are an integral multiple of the dot pitch, the printing wires of the groups at opposing positions are driven simultaneously, and the printing wires and electromagnets arranged in a circumferential manner are driven simultaneously. The force applied to the print head, which has a mechanism, is well balanced and does not generate unnecessary vibrations. For this reason,
It can greatly contribute to low noise. In this case, the opposing groups are driven simultaneously, but since these groups are spaced so that they face each other, the space is large and magnetic interference does not occur.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

First, the general structure and operation of the print head will be explained with reference to FIGS. 1 and 2. FIG. 1 shows a longitudinal sectional view of the printing head, and FIG. 2 shows its front view.

As shown in these figures, the print head has an outer frame structure including a guide frame 1, a head frame 2, and an outer plate 3. As shown in FIG.
The guide frame 1 includes a guide 5A for the printing wire 4 and a center guide 5B thereof. A protrusion 6 is formed on the outer periphery of the outer plate 3 to improve heat radiation.

In the space defined by the head frame 2 and the outer plate 3, there is a lever section 7 provided with the printing wire 4 and a drive mechanism 7A for the lever section 7.
is provided. As shown in FIG. 2, a plurality of lever portions 7 are provided in the head frame 2 in the radial direction and in the circumferential direction. This lever part 7
The lever body 8, the suction member 9 and the spring member 10
It consists of The printing wire 4 is fixed to the tip of the lever body 8. The suction member 9 is made of a magnetically permeable material, and has a lever body 8 fixed to one end thereof, and a plate-shaped spring member 10 fixed to the other end thereof. The end of the spring member 10 is provided with a hole for adjusting the spring force.

As shown in FIG.
3. A permanent magnet 14 is provided between the yokes 12 and 13, and a coil 15 is provided on the first yoke 12. The second yoke 13 has a magnetic pole surface 13A disposed close to the magnetic pole surface 12A of the first yoke 12. These magnetic pole faces 13
A and 12A face the suction material 9. The first yoke 12, the second yoke 13, the permanent magnet 14, and the attraction member 9 form a magnetic circuit of the permanent magnet 14 and the coil 15. The permanent magnet 14 generates a magnetic flux that attracts the attraction member 9 toward the yoke. The coil 15 is set to cancel the magnetic flux of the permanent magnet 14 by its excitation.

The first yoke 12, the second yoke 13, the permanent magnet 14, and the outer plate 3 are fastened and fixed to the head frame 2 by screws 16.
Normally, the lever part 7 attracts the magnetic pole faces 12A, 13A of the first yoke 12 and the second yoke 13 by the magnetic attraction force generated by the permanent magnetic flux, so that the attraction member 9 attracts the yokes 12, 13. It is located at the front. The pivot point of this lever part 7 is the second
The magnetic pole surface 13A of the yoke 13 and the edge portion 9A of the attraction member 9 that contacts the magnetic pole surface 13A of the yoke 13 constitute the magnetic pole surface 13A of the yoke 13.
A servo board 17 is provided on the surface of the second yoke 13 that faces the printing paper. When the lever part 7 rotates,
In order to prevent the head frame from swinging, the head frame 2 is provided with a lever guide 18 that guides the lever body 8 of the lever portion 7.
It is equipped with

The means for adjusting the spring force of the spring member 10 includes a push-in member 19 screwed into the head frame 2. This pushing member 19 has a tapered portion 2 at its tip.
It is equipped with 0. This tapered portion 20 is the spring member 1
It engages a hole provided at the end of 0. By pushing and pulling the pushing member 19, the spring member 1
0 can be tilted and its spring force can be adjusted.

Next, the operation of the print head described above will be explained.

Before printing starts, the attraction member 9 is attracted by the magnetic attraction force of the permanent magnet 14 as shown in FIG.
It is attracted to the magnetic pole faces 12A and 13A of the first yoke 12 and the second yoke 13. At this time,
The spring member 10 is tilted and stores strain energy. The spring force associated with this strain energy can be adjusted by pushing in and out of the pushing member 19.

Next, when current is applied to the coil 15, the permanent magnet 14
Since the magnetic flux is canceled out, the attraction member 9 rotates around the circular fulcrum formed by the magnetic pole surface 13A and the edge portion 9A of the attraction member 9 due to the spring force of the spring member 10. For this reason, the printing wire 4
is guided by the guide 5A and center guide 5B of the guide frame 1, and its tip is struck by the platen via the ink ribbon and printing paper. As a result, dots D forming the character "Kan" are printed on the printing paper as shown in FIG.

In the above-described printing operation, the A of the printing wire 4
The distance Q between the column and B column is an integral multiple of the dot pitch P +
When set to 1/2 pitch, for example, in order to print the printing wires 4 of columns A and B at the same position, their driving timings are shifted by half a period as shown in FIG. It turns out.

Next, one embodiment of the present invention will be described with reference to FIG. The basic configuration of the print head is as shown in FIGS. 1 and 2, and FIG. 5 shows the arrangement of the print wires as viewed from the recording surface side. In FIG. 5, a total of 24 printing wires are prepared. The 24 print wires are now divided into four groups. That is, 4A ₁ ~ 4
A ₃ and the group obtained from 4B ₁ to 4B ₃ (hereinafter, the first
(referred to as a group). , the group obtained from 4A ₄ to 4A ₉ (hereinafter referred to as the second group), 4A ₁₀ to 4A ₁₂ and 4
The group obtained from B ₁₀ to 4B ₁₂ (hereinafter referred to as the 3rd group) and the group obtained from 4B ₄ to 4B ₉ (hereinafter referred to as the 4th group)
It's called a group. ). Regarding the first group, the distance Q between the printing wires in the printing direction between the adjacent second group or the fourth group is set to a value obtained by adding P/2 to an integral multiple of the dot pitch P. Regarding the second group, the relationship between the adjacent first group and third group is similar. The other groups have similar relationships with the husband's neighboring groups. Note that the second group and the fourth group are expanding outward. Further, among the groups of printing wires arranged in a circumferential manner, the groups in opposing positions are set to be an integral multiple of the dot pitch P. In other words, the value of the distance Q between the first group and the third group, which are opposite to each other, is Q
=0, and the value of the distance Q between the second group and the fourth group is Q=9P. This results in
Since the first group and the third group are driven simultaneously, the print head is not driven unevenly, and unnecessary vibrations are less likely to occur. The same applies to the second group and the fourth group.

In this way, in the embodiment shown in FIG. 5, since the adjacent groups are not driven at the same time for a certain group, the magnetic interference is greatly reduced, and the distance between the opposing groups is increased by an integer multiple. Since they are closely spaced, they must be driven simultaneously.
Noise generation due to vibration can be significantly reduced. Moreover, since the arrangement of the tips of the printing wires 4 is configured to bulge outward as a whole, the amount of deflection of the printing wires 4 is uniform, and each frictional force between each printing wire 4 and a guide etc. becomes uniform. Therefore, the operating characteristics become uniform, and it is also expected that the printing characteristics will be improved.

Next, another embodiment of the present invention shown in FIG. 6 will be described. In this example, the printing wire is divided into 12 groups,
The number of printing wires driven simultaneously is reduced. This embodiment can be said to be preferable in terms of reducing magnetic interference, noise, and low power driving.

〔Effect of the invention〕

As explained in detail above, according to the present invention,
The number of adjacent electromagnetic mechanisms and printing wires to be driven simultaneously is small, and moreover, groups located at opposing positions are driven simultaneously. Therefore, magnetic interference and noise can be reduced.

[Brief explanation of drawings]

Fig. 1 shows the general configuration of a print head, and is a vertical cross-sectional side view of the print head, Fig. 2 is a front view of the print head shown in Fig. 1, and Fig. 3 is a diagram for explaining the prior art. , FIG. 4 is a diagram showing a print timing chart, and FIGS. 5 and 6 are diagrams each showing an embodiment of the present invention. 1... Guide frame, 2... Head frame, 4... Printing wire, 7... Lever part, 7A...
... Drive mechanism of lever portion 7, 8... Lever body, 9...
...Suction member, 10... Spring member, 11... Hole, 1
4... Permanent magnet, 15... Coil, 19... Pushing member.

Claims (1)

[Claims] 1. A large number of printing wires are arranged in a staggered manner in a direction perpendicular to the printing head running direction in a portion facing the printing paper, and these printing wires and a large number of electromagnetic mechanisms that drive the printing wires are provided. The printing wire and the electromagnetic mechanism are divided into even-numbered groups of 4 or more, and the distance between the printing wires in the printing head running direction between each of the adjacent groups is , at the tip of the printing wire, the value is set to an integral multiple of the dot pitch constituting the character plus 1/2 dot pitch; The printing head is characterized in that the spacing in the printing head running direction is set to a value that is an integral multiple of the dot pitch at the tip of the printing wire. 2. In the printing head according to claim 1, the printing head divided into a plurality of groups is arranged so as to gradually bulge outward from the center of the printing head in the portion facing the printing paper. A print head featuring: