JPH037162Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a dot line printer that achieves high printing speed by reducing the weight of the printing hammer drive device.

As shown in FIG. 1, the printing hammer drive device includes a printing hammer consisting of a plate spring 5 with a printing pin 6 attached to the printing surface, a permanent magnet 1, a rear yoke 3, and an upper leg portion of the rear yoke 3, that is, a pole portion 2. It consists of a wound release coil 4 and a magnetic circuit structure that attracts and holds the leaf spring 5. The lower end of the leaf spring 5 is attached to the lower end of the yoke spacer 7 with a fixing screw 8 and a fixing plate 9 interposed therebetween.

The leaf spring 5 is constantly attracted and held by the pole portion 2 of the rear yoke 3 by the magnetic attraction force of the permanent magnet 1. When the release coil 4 is energized, the magnetic attraction force is canceled out, and the leaf spring 5 flies due to its elastic force, causing the printing pin 6 to collide with a platen (not shown) via a sheet of paper (not shown) and an ink ribbon (not shown). As a result, dots are printed on the paper.

As shown in FIG. 2, a plurality of such printing hammer driving devices are arranged in the row direction to form a hammer bank, and the hammer bank is reciprocated in the row direction and the paper is intermittently fed one dot row at a time for printing. There is.

In order to achieve a high printing speed in such a printer, two methods have been proposed: increasing the reciprocating speed of the hammer bank, and installing the hammer banks in two stages, upper and lower.

In order to reciprocate the hammer bank at high speed, it is essential to reduce the weight of the hammer bank, that is, the printing hammer drive device. The printing hammer drive device shown in the first figure is
The leaf spring 5 is attracted by the magnetic flux generated by the permanent magnet 1 and passing through the rear yoke 3 and the pole 2, but since the magnetic path is long, the leakage of the magnetic flux is generally large. Permanent magnet 1 is used to obtain the necessary amount of magnetic flux at the attraction part of pole 2.
It is difficult to reduce the weight because it is larger than a printing hammer drive device with an efficient magnetic circuit structure and also requires large components such as the rear yoke 3.

Furthermore, if the printing hammer drive device is installed in two stages, upper and lower, the release coil 4 will be close together, resulting in poor cooling efficiency, and the release coil 4 will generate heat, making it difficult to achieve its full performance, making it difficult to achieve high speed. It was hot.

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, to enable high printing speeds, and to provide an inexpensive printer.

The present invention is designed to increase the printing speed by installing printing hammer drive devices in upper and lower stages with a shortened length of the magnetic circuit that serves as the path of magnetic flux, and to prevent the cooling efficiency from decreasing. The present invention will be described below with reference to the drawings.

FIGS. 3 and 4 show a printing hammer driving device constituting the dot line printer of the present invention. Note that the same reference numerals as in FIGS. 1 and 2 indicate the same parts. A rear yoke 3 extends parallel to the permanent magnet 1 and is provided on the rear surface thereof, and is provided at approximately the same height as the permanent magnet.
0, poles 20 that are branched from the rear yoke 30 into at least a number equal to the number of leaf springs 5 and extend at a predetermined angle such that their upper ends are close to the back surface below the printing pins 6 of the leaf springs 5; The difference from FIGS. 1 and 2 is the release coil 40 wound around the pole 20.

As is clear from the illustrated configuration, since the rear yoke 30 can be made smaller and the magnetic path can be significantly shortened, leakage magnetic flux is reduced and the permanent magnet 1 can be made smaller. As a result, the weight of the printing hammer drive device can be reduced, high-speed reciprocation is possible, and high printing speed can be achieved.

5 and 6 show the main parts of the dot line printer of the present invention, in which the upper and lower printing hammer drive devices are connected by a connecting plate 10 attached to the back side of the rear yoke 30. FIG. In this case, the upper and lower leaf springs 5 are arranged alternately.

In this configuration, since the upper and lower release coils 40 do not come close to each other, the resistance as a passage for cooling air is reduced, and there is an effect that sufficient cooling can be achieved with a small-capacity cooling device. There is also the effect that magnetic interference between the upper and lower release coils 40 is reduced.

As described above, according to the present invention, it is possible to improve the printing speed by installing the printing hammer drive devices, which are light in weight by shortening the length of the magnetic circuit, in the upper and lower stages. In addition, the distance between the upper and lower release coils can be increased, cooling efficiency can be improved, and magnetic interference can be reduced.

[Brief explanation of the drawing]

1 and 2 are a sectional view and a perspective view showing an example of a conventional printing hammer drive device, and FIGS. 3 and 4 are
The figure is a cross-sectional view and a perspective view showing a printing hammer driving device used in the present invention, and FIGS. 5 and 6 are a cross-sectional view and a perspective view showing an embodiment of the present invention. In the figure, 1 is a permanent magnet, 2 and 20 are poles, 3 and 30 are yokes, 4 and 40 are release coils,
5 is a leaf spring, 6 is a printing pin, 7 is a yoke spacer, 8 is a fixing screw, 9 is a fixing plate, and 10 is a connecting plate.

Claims (1)

[Scope of utility model registration request] a permanent magnet extending in the row direction along the printing position;
A yoke spacer extending parallel to the permanent magnet and provided on the front thereof, and a printing pin near the upper end,
A plurality of plate springs whose lower ends are attached to the yoke spacer and are arranged in the row direction; a rear yoke extending parallel to the permanent magnet and provided on the rear surface thereof; and at least the number of plate springs from the rear yoke is equal to the number of the plate springs. A printing hammer drive device comprising a pole which is branched into a number of branches and whose tip extends at a predetermined angle with an inclination close to the lower back surface of the printing pin of the leaf spring, and a release coil wound around the pole. A dot line printer characterized in that a pair of dots are arranged above and below a printing position so that the printing pins on the respective leaf springs are alternately positioned along the row direction.