JPH0335555Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a printing hammer drive device in a daisy wheel printer.

BACKGROUND TECHNOLOGY As shown in FIGS. 4 and 5, a coil 52 is wound around a core 51 erected on a yoke 50.
A shaft 54 that rotatably holds the armature 53 at zero.
A printing hammer 56 made of synthetic resin with a metal material 55 inserted therein is urged in the return direction (counterclockwise) by a spring 57 and rotatably fitted to the shaft 54, and the armature hammer 56 is absorbed into the core 51. 53 to hit the back side of the printing hammer 56 to remove the printing hammer 56.
There is one in which the type part of the daisy wheel is struck.

Although not shown, the yoke 50 of the electromagnet is held by a wheel holder, and in the center of this wheel holder, there is a wheel holder that elastically presses the center of the daisy wheel against the wheel drive unit and is rotatable and moves back and forth in the axial direction. freely held, printing hammer 5
6 is located on a vertical plane passing through the center of the wheel holder.

Problems to be Solved by the Invention However, since the impact is made at three locations: between the core 51 and the armature 53, between the armature 53 and the back of the printing hammer 56, and between the printing hammer 56 and the daisy wheel, Printing noise is too loud.

For this reason, there are some devices in which the printing hammer 56 is driven by a plunger type electromagnet.
As mentioned above, since the printing hammer and the wheel holder are located on the same vertical plane, the plunger type electromagnet is attached to the wheel holder so as to face the back side of the printing hammer. Therefore, there is a problem that the thickness dimension of the wheel holder in the front-rear direction increases.

This invention was made in view of the above points, and aims to provide a printing hammer drive device that can reduce the thickness of the wheel holder and reduce printing noise.

Means for Solving the Problems This invention provides a wheel holder 1 to which a wheel holder 7 that presses the center of the daisy wheel 4 is attached rotatably and can move back and forth in the axial direction. A printing hammer 13 having a striking part 10 for striking the back side of the type part 3 of the daisy wheel 4 on a surface is rotatably attached to the wheel holder 1, and the printing hammer 13 is attached to the side from a vertical plane passing through the center of the daisy wheel 4. A blow receiving portion 12 is formed which is displaced toward the blow receiving portion 1 , and the upper end thereof is
An electromagnet 17 having a plunger 24 colliding with the lower part of the electromagnet 17 is positioned on the side of the wheel holder 7 and attached to the wheel holder 1.

Operation: The plunger 24 of the electromagnet 17 is made to collide with the striking part 12 to rotate the printing hammer 13, and the striking part 10 of the printing hammer 13 is made to collide with the back surface of the type part 3 of the daisy wheel 4 to print. plunger 2
4 and the striking part 12 can be in constant contact with each other, so that the collision point is at one place between the type part 3 and the striking part 10, and printing noise is reduced. Further, the printing hammer 13 is formed with a striking portion 12 that is displaced laterally from the vertical plane passing through the center of the daisy wheel 4, and the electromagnet 17 is displaced laterally from the vertical plane passing through the center of the daisy wheel 4. By arranging it below the wheel holder 1, the thickness of the wheel holder 1 can be reduced.

Embodiment An embodiment of this invention will be explained based on FIGS. 1 to 3. 1 is a wheel holder. This wheel holder 1 is rotatably held by a carrier (not shown) that moves parallel to the platen 2 and can be fixed at any position. The rotating direction is a direction in which the platen 2 approaches and leaves the platen 2.
This wheel holder 1 has many type parts 3 on the outer periphery.
A housing part 5 is formed to accommodate the daisy wheels 4 in which the daisy wheels 4 are arranged, and a wheel holder 7 that presses the center of the daisy wheels 4 is rotatably and slidably fitted into a shaft hole 6 formed in the center. . The wheel holder 7 is urged toward the platen 2 by the spring 8, but is prevented from coming off by fixing a retaining ring 9 that abuts the back surface of the wheel holder 1 to the shaft of the wheel holder 7.

Next, a striking portion 10 is positioned on a vertical plane passing through the centers of the daisy wheel 4 and the wheel presser 7.
and an extending piece 1 extending laterally from this striking part 10.
A printing hammer 13 made of sheet metal is provided, which is integrally formed with a hammer 1 and a shock receiving part 12 continuous with the end of the extending piece 11. It is urged in the direction of separation and is rotatably held in the wheel holder 1 by a shaft 15. Weights 16 are crimped on both sides of the striking portion 10.

Furthermore, the wheel holder 1 has a wheel presser 7.
An electromagnet 17 is fixed at a position shifted laterally from the center. This electromagnet 17 has a rectangular container-shaped yoke 1 fixed to the wheel holder 1 with a screw 18.
9, a yoke 20 that closes the opening of the yoke 19, a bobbin 22 that holds a coil 21, and a plunger 24 that has a small diameter shaft portion 23 that projects from the yoke 19. The bobbin 22 is made of synthetic resin with good electrical insulation and wear resistance, and has a cylindrical guide portion 25 that slidably holds the large diameter portion of the plunger 24 and a small diameter shaft portion 23 of the plunger 24. It is integrally provided with a cylindrical guide portion 26 that is slidably held. York 19, 20
a fitting portion 27 into which the guide portions 25 and 26 are fitted;
28 are arranged on the same axis.
A retaining ring 30 that comes into contact with an elastic member 29 fixed to the end face of the yoke 19 is fixed to the shaft portion 23 .

Although not shown in the drawings, the carrier is provided with a wheel driving section facing the front surface of the wheel holder 7, which is connected to a motor and is rotatable.

In such a configuration, the daisy wheel 4
is elastically pressed by the wheel presser 7 and chucked by the wheel drive unit, and by rotating the wheel drive unit by a predetermined angle, the desired type portion 3 faces the striking unit 10. When the coil 21 is energized, the plunger 24 slides upward and pushes up the impact receiving part 13, and the printing hammer 13 rotates about the shaft 15 and hits the back surface of the type part 3 with the hitting part 10. Printing is thereby performed. The coil 21 is energized instantaneously, and the printing hammer 13 returns while pressing down the plunger 24 by the force of the torsion spring 14. The impact of the plunger 24 returning is absorbed by the elastic material 29. Further, since the upper end of the shaft portion 23 of the plunger 24 and the impact receiving portion 12 can be kept in contact with each other at all times, the collision portion is located at one location between the type portion 3 and the striking portion 10, thus preventing printing. Noise can be reduced.

Furthermore, the daisy wheel 4 is attached to the printing hammer 13.
By forming the impact receiving part 12 that is displaced laterally from a vertical plane passing through the center of the wheel holder 1, and by moving the electromagnet 17 to the side of the wheel holder 7 and placing it in a dead space below the printing hammer 13, the front and rear of the wheel holder 1 The thickness in the direction can be made thinner.

Furthermore, since the printing hammer 13 is made of sheet metal, material costs and processing costs can be reduced.

Effects of the invention As mentioned above, this invention forms a striking part on the printing hammer that is displaced laterally from the vertical plane passing through the center of the daisy wheel, moves the electromagnet to the side of the wheel holder, and moves the electromagnet to the bottom of the printing hammer. By arranging the wheel holder, the longitudinal dimensions of the wheel holder can be made thinner, and the plunger and the impact receiver can be kept in constant contact, thereby reducing collision points and reducing printing noise. It has effects such as being able to reduce

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of this invention, in which Figure 1 is an exploded perspective view, Figure 2 is an enlarged front view, Figure 3 is a further enlarged vertical side view,
FIG. 4 is an exploded perspective view showing a conventional example, and FIG. 5 is a longitudinal sectional side view thereof. 1... Wheel holder, 3... Type part, 4...
Daisy wheel, 7...Wheel holder, 10...
...Hitting part, 12...Blow receiving part, 13...Printing hammer, 17...Electromagnet, 24...Plunger.

Claims (1)

[Scope of utility model registration request] A wheel holder is provided in which a wheel holder that presses the center of the daisy wheel against the wheel drive unit is rotatably attached and movable back and forth in the axial direction. A printing hammer having a striking part for striking the daisy wheel is rotatably attached to the wheel holder, a striking receiving part is formed on the printing hammer and is displaced laterally from a vertical plane passing through the center of the daisy wheel, and the upper end is connected to the striking part. 1. A printing hammer drive device, characterized in that an electromagnet having a plunger that collides with a lower part of a receiving portion is located on a side of the wheel holder and attached to the wheel holder.