JPS5845954B2 - Printing element drive device using a diaphragm - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dot printer, and more particularly to a printing element drive device using a diaphragm.

Conventionally, there are various configurations of dot printers using a moving coil drive system.

A typical example is to selectively apply a voltage to a moving coil fixed to a vibrating element, use the resulting vibrational displacement of the vibrating element to drive a printing element, and use this printing element to form dots. There is something I tried to do.

However, according to a dot printer with such a configuration, it is necessary to instantaneously apply large displacement and large force to the vibrating element.
For this purpose, it was necessary to provide an arrangement that would either allow current to flow through the moving coil or increase the magnetic flux density across the moving coil.

Additionally, there are drawbacks such as an increase in heat generation and difficulty in miniaturizing the device due to the need to avoid magnetic interference between adjacent devices.

In addition, some conventional examples, such as the printer head disclosed in Japanese Patent Application Laid-Open No. 52-30519, have vibrating elements that are made to vibrate continuously with a substantially constant amplitude and period; The structure for selectively transmitting the amplitude to the printing elements is very complicated, and has the disadvantage that it is not suitable for mass production.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the prior art described above, and to provide a printing element drive device using a diaphragm that is simple in structure and can be manufactured at low cost.

1 and 2, the diaphragms 1 are arranged radially, and a mass adjustment plate 2 is provided at one end (free end) of the diaphragms 1.
is fixed thereto, and this mass adjustment plate faces a printing pin 4 at the rear end of the printing wire 3, which is shown as an example of a printing element, in a relationship as will be described later.

Although not shown in the drawings, the printing pins 4 are supported on the same circumference by a guide member, and the tips of the printing wires 3 are slidably supported in a vertical line, and the printing pins 4 (
The printing wire 3) is moved backward (second direction) by the spring force of the return spring.
(left side of the figure).

The diaphragm 1 is always continuously vibrated with a substantially constant amplitude and period (one being its natural frequency) via a vibration drive means.

According to this embodiment, the vibration driving means includes a moving coil 5 fixed to the back surface of the diaphragm 1, a cylindrical counter-magnetic pole 7 disposed on a non-magnetic support plate 6, and a central bottom portion of the counter-magnetic pole. It is composed of a permanent magnet 8 fixed to the permanent magnet 8 and an inner magnetic pole 9 fixed to the permanent magnet.

The counter magnetic pole 9 and the moving coil 5 are magnetized with different polarities by the permanent magnet 8, and the moving coil 5 is inserted into a magnetic gap 10 formed by both magnetic poles.

In addition, the diaphragm 1 is moved to the reset position (
The neutral resting position can be selectively switched between the solid line position in Figure 2) and the set position (the chain line position in Figure 2).1. The diaphragm 1 (mass adjustment plate 2) cannot hit the printing pin 4 when it is in the reset position, but can hit the printing pin 4 only when it is in the set position.

To explain one example of this electromagnetic switching device, a switching lever 11 to which the rear end of the diaphragm 1 is fixed is attached to a support plate 12.13 and a printed circuit board 14 with its arm 11a.
The support shafts 15 are rotatably supported by the bearing holes 12a of the support plate 12 and the front surface of the support plate 13, and are arranged circumferentially.

Each support shaft 15 is prevented from coming out by a bifurcated leaf spring 17 fixed to the front surface of the support plate 12 via a screw 16.

A coil bobbin 19 around which an excitation coil 18 is wound is fixed to the back surface of the printed circuit board 14, and an arm 11a projects through the hollow core of the coil bobbin 19.

Behind the coil bobbin 19, yoke plates 20, 210 and magnetic pole parts 20a and 21a are located, and an arm 11a is inserted into the gap between each magnetic pole part.

The yoke plates 20, 21 (magnetic pole parts 20a, 21a) are the only permanent magnet 2 in the form of a disk, which is sandwiched 1.
2, they are magnetized to have different polarities.

The yoke plates 20 and 21 are fixed to a support member 13 (not shown).

The switching lever 11 of the electromagnetic switching device of this embodiment configured as described above has two stable rest positions.

One is the solid line position in Figure 2 (reset position) where the arm 11a is attracted to the magnetic pole part 20a, and the other is the chain line position in Figure 2 (set position) where the arm 11a is absorbed by the magnetic pole part 21a. It is.

Note that the support plate 6 is fixed to the yoke plate 21 via pillars 23.

Next, the operation will be explained.

When a drive signal is supplied to the moving coil 5 at the solid line position in FIG. 2 (reset position), the diaphragm 1 is caused to vibrate with a constant amplitude at or near its natural frequency.

In this state, the mass adjusting plate 2 at the free end of the diaphragm 1 cannot strike the printing pin 4, so no dots are formed.

Therefore, when a short pulse current is applied to the excitation coil 18 and the arm 11a is magnetized to the north pole, the arm 11a is repelled from the magnetic pole part 20a and is attracted to the magnetic pole part 21a, and instantly rotates counterclockwise in FIG. , is attracted to the magnetic pole part 21a.

That is, the stable rest position of the switching lever 11 is switched from the reset position to the set position.

Then, the diaphragm 1 vibrates around the position shown by the chain line, and when the amplitude is approximately at the maximum on the right side of FIG. 2, the mass adjustment plate 2 hits the printing pin 4 and a dot is formed.

Next, when a short pulse current of opposite polarity to the above is applied to the excitation coil 18 and the arm 11a is magnetized to the S pole, the arm 11a is repelled from the magnetic pole part 21a and
a, it instantly rotates clockwise in FIG. 2, and is attracted to the magnetic pole portion 20a.

That is, the stable rest position of the switching lever 11 is switched from the set position to the reset position again, and no dots are formed.

Therefore, by switching the switching lever 11 between the reset position and the set position with appropriate timing during head scanning, it is possible to arbitrarily form, for example, characters in a 5x7 dot matrix pattern at a very high speed. It is.

Note that the vibration driving means is not limited to the above embodiment.

For example, as another example, a piezoelectric element such as barium titanate may be attached to the diaphragm 1.

Furthermore, the electromagnetic switching device is not limited to the above configuration.

The above embodiment is just an example of the magnetic type, and for example, as in the example shown in FIG. 3, the switching lever 11,
Stopper 2 that determines the reset position of this switching lever
4, a spring 25 that brings the switching lever 11 into elastic contact with the stopper 24, and a U-shaped iron core 27 that attracts the switching lever 11 to the set position by applying a voltage to the excitation coil 26.

According to the printing element driving device of the present invention described in detail above, the diaphragm is continuously vibrated with a substantially constant amplitude and pitch period, and the electromagnetic switching device is used to move the diaphragm to the rear end of the printing wire. Desired characters, etc. are formed by selectively displacing the part (printing pin) to a position where it can be hit and a position where it cannot be hit, so it can print at a very high speed with low current consumption. can be made to move.

Especially when forming dots continuously, this method is much more advantageous than conventional methods.

Furthermore, according to this configuration, it is technically easy to set the vibration amplitude and striking force of the diaphragm to be sufficiently large, so that the printing operation is stable and clear dots can be formed.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which FIG. 1 is a partially sectional front view, FIG. 2 is a sectional view taken along line n-II in FIG. 1, and FIG. 3 is an electromagnetic switching device. FIG. 3 is a sectional view showing another embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Vibration plate, 3... Printing element, 4... Printing pin, 57.8, 9, 10... Vibration drive means, 11, 11
a18.20, 20a, 21.21a, 22, 2425
．． 26.27...Electromagnetic switching device.

Claims (1)

[Claims] 1. A diaphragm that is continuously vibrated with a substantially constant amplitude and period via a vibration driving means and that faces the rear end of the printing element at a predetermined distance, and a base of the diaphragm that is attached to the diaphragm. A printing element driving device using a diaphragm, comprising an electromagnetic switching device that selectively displaces the diaphragm between a position where the diaphragm can collide with the rear end of the printing element and a position where it cannot collide.