JPS6356071B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wire head drive device for a dot printer, and more particularly to an improvement for shortening the printing operation time for one dot.

Figure 1 shows a schematic configuration of a wire head drive device in a conventional dot printer.
. . . is a wire head, and 2 . . . is a driving electromagnet. The wire head 1... is disposed within the guide 3 so as to be able to move forward and backward in the vertical direction in the figure, and is moved downward in the figure to perform the printing operation, and then returned to the upward direction in the figure by the return spring 4... I'm starting to do that. The driving electromagnets 2 are provided in the same number as the wire heads 1, and these are arranged in a circular shape around the guide 3 in a bottomed cylindrical case 5 connected to one end of the guide 3. There is. Each electromagnet 2 includes a U-shaped core 8 formed by a rod-shaped core 7 erected on the bottom plate of a common yoke 6 disposed in the case 5, a coil 9 wound around the core 7, and one end of the electromagnet 2. It is located at the end of the peripheral wall of the yoke 6, and the other end is connected to the case 5.
The armature 10 extends to the vicinity of the center. One end of the armature 10 is pressed and held against the peripheral wall end of the yoke 6 by a pressing spring 11, and when the other end is attracted to the core 7 and rotates using this one end as a rotational fulcrum, each wire head is connected at this other end. 1
is configured to drive the terminal end of the print head in the direction of the printing operation. The opening of the case 5 is closed by a bar 12, and a cushion material 13 is attached to the center of the inner surface of the cover 12, so that the other end of each armature 10 is received from the opposite drive direction side. ing.

Therefore, when a predetermined coil 9 is energized, the armature 10 rotates to form a closed magnetic path, the other end of the armature drives the wire head 1, and the tip of the wire head 1 is connected to the ink ribbon 14.
The printing paper 15 is then struck against the platen 16, and one dot is printed on the printing paper 15. Next, when the current supply to the coil 9 is stopped, the wire head 1 is returned by the return spring 4 while pushing back the armature 10. At this time, amateur 10
The other end collides with the cushion material 13 and vibrates together with the wire head 1, but eventually comes to rest and prepares for the next printing operation.

FIG. 2 shows the operation timing of the wire head described above, and the total time required to print one dot is: forward movement time T ₁ + return time T ₂ + vibration time T ₃ . Therefore, in order to speed up the printing operation, it is desirable to shorten these times, particularly the forward movement time _T1 and the return time _T2 .

Therefore, first of all, to shorten the forward movement time _T1 , it is necessary to increase the current value flowing through the coil 9, but in reality, the electromagnet is often used in a saturated state, so in order to increase the current value, A large electromagnet with a large cross-sectional area of the magnetic path must be used, leading to an increase in the size and cost of the entire device.

Next, in order to shorten the return time _T2 , it is possible to make the return spring 4 stronger, but since the elasticity of the return spring 4 becomes an obstacle when driving the wire head 1 in the printing operation direction, we decided to make it stronger. As a result, the forward movement time _T1 becomes longer, and an increasingly larger electromagnet must be used.

The present invention was developed based on the above circumstances, and its object is to increase the speed of printing operations while reducing the size and cost of a wire head drive device for a dot printer.

The configuration of the present invention will be explained below based on the embodiment shown in FIG.

In the figure, 22... is a driving electromagnet provided corresponding to each wire head 1..., and each electromagnet 22...
, a U-shaped core 28 consisting of a set of two rod-shaped cores 27A and 27B erected on a common flat yoke 26 disposed on the inner bottom surface of the case 5, and one core 27.
A coil 29 is wound around A, and one end is connected to the core 27.
The armature 30 is located at the top end of the case 5 and has its other end extended to the vicinity of the center of the case 5.
It is pressed and held at the top of A. The pair of cores 27A and 27B are arranged in parallel in the radial direction inside the case 5, and are arranged on the outside (the side far from the center of the case 5).
A coil 29 is wound around a core 27A. In addition, an auxiliary electromagnet 31 is located at the center of the inner surface of the cover 12 that closes the opening of the case 5.
A cushion material 13 similar to that shown in FIG. 1 is attached to the end face of this electromagnet 31. This electromagnet 31 is constructed by winding a coil 31A around a core 31B. and each amateur 30
The rotating end of the wire head 1 is arranged opposite to the terminal end of the wire head 1, and normally comes into contact with the cushion material 13 by the return spring 4 provided on the wire head 1, and when it is rotated by being attracted by the inner core 27B, it is used for return. Spring 4
The wire head 1 is pressed and driven against the pressure. The relationship between the direction of energization to each electromagnet coil 22 and the direction of energization to the electromagnet 31 is determined by the polarity of the side of the electromagnet 31 facing the armature 30,
The polarity on the armature fulcrum side is made to be the same polarity (for example, both are N poles).

With the above configuration, the electromagnet 22,3
By energizing the coils 29 and 31A of No. 1, the rotating end side of the armature 30 becomes the N pole, and the electromagnet 3
Since the polarity of the side facing the armature 30 of 1 is N pole, the repulsive force from the electromagnet 31 is applied to the armature 3
This will act to help the rotation of 0. Therefore, the amateur 30 has the above repulsive force and the inner core 27B.
It rotates easily at high speed due to the suction force of
The wire head 1 can be strongly driven. At this time, the repulsive force from the auxiliary electromagnet 31 acts on the tip of the armature 30, so the armature 30
can obtain sufficient turning force even with a relatively weak repulsive force,
As the electromagnet 31, a small one can be used. Further, when the power supply to the driving electromagnet 22 is cut off, the armature 30 is returned to the initial position by the return spring 4, but at this time, an attractive force by the auxiliary electromagnet 31 acts on the armature 30.

Therefore, according to this wire head drive device, the armature 30 can be rotated at high speed without increasing the size of the electromagnet 22, and the forward movement time of the wire head 1 (T ₁ in FIG. 2) can be increased. can be shortened. In addition, when the armature 30 returns, the return speed is increased by using the attraction force of the electromagnet 31, so the total time (T ₁ + T ₂ + T ₃ ) required for printing one dot is significantly shortened, resulting in a smaller size. At the same time, it is possible to increase the speed. Furthermore, when the electromagnet coil 29 is wound around the core 27A on the armature fulcrum side as in this embodiment, the magnetic path between the coil 29 and the electromagnet 31 is shortened, and the electromagnet 31
The repulsive force is strengthened and a more favorable effect can be obtained.

Furthermore, by changing the amount of electricity applied to the auxiliary electromagnet 31 during forward movement and return, the repulsive force and attraction force to the armature 30 can be changed, so that the impact force of the wire head 1 can be adjusted appropriately during forward movement.
Moreover, when returning, the amateur 30 can be returned at high speed.

As described in detail above, according to the present invention, with a simple configuration that only includes an auxiliary electromagnet, printing can be performed without making the driving electromagnet particularly large, that is, while achieving miniaturization and cost reduction. It is possible to provide a wire head drive device for a dot printer that can operate at high speed and can adjust the repulsive force and attractive force of the armature using an auxiliary electromagnet.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional example, FIG. 2 is an operation timing diagram of a wire head, and FIG. 3 is a sectional view showing an embodiment of the present invention. 1...Wire head, 2, 22...Driving electromagnet, 4...Return spring, 28...U-shaped core, 2
9...Coil, 30...Amateur, 31...Auxiliary electromagnet.

Claims (1)

[Claims] 1. A plurality of wire heads urged in the anti-printing direction by a return spring, a coil wound around one U-shaped core, and one end of an armature corresponding to one or the other core. a plurality of driving electromagnets positioned as fulcrums and rotating the other end of the corresponding armature in a direction to form a closed magnetic path to drive each wire head in the printing operation direction; One piece is commonly arranged so as to face the tip of the other end of each armature from the opposite drive direction side, and the polarity of the side facing each armature is the same as the polarity of the core on the armature fulcrum side of the driving electromagnet. A dot printer wire head drive device equipped with an auxiliary electromagnet. 2. A wire head drive device for a dot printer according to claim 1, wherein a coil of a drive electromagnet is wound around a core on the armature fulcrum side.