JPS646288Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in impact printer heads.

In an impact type printer head, an arm-shaped leaf spring having a printing element such as a wire, a hammer, a printing body, etc. at its tip has its root portion tightly fixed to a support plate. When using such a printer head for a long period of time, dust gradually enters and accumulates between the base of the leaf spring and the support plate, eventually causing malfunction.

The present invention aims to eliminate the above-mentioned drawbacks of the conventional technology, and one embodiment thereof will be described below.

In FIGS. 1 and 2, a front yoke 1, a permanent magnet 2, a rear yoke 3, and a center yoke 4 constitute a magnetic circuit device. The front yoke 1 has a substantially disk shape, and has a hole formed in its center. The permanent magnet 2 is formed into an annular shape and is fixed to the back surface of the front yoke 1. The rear yoke 3 fixed to the back of this permanent magnet 2 is
It is formed into a cylindrical cap shape, and a cylindrical center yoke 4 is fixed to the bottom of the cap. This center yoke 4 extends toward the center hole of the front yoke 1,
A coil 5 surrounding the permanent magnet 2 and the rear yoke 3 is inserted into a hollow space inside the permanent magnet 2 and the rear yoke 3.

A spacer plate 6 and a plate material 7 are provided on the front surface of the front yoke 1.
And a support plate 8 is fixed via a mounting pin 9. The support plate 8 is formed to have an L-shaped cross section, and the upper part of the magnetic circuit device having the above structure appears above the notch 10 thereof. As shown in FIG. 3, the plate member 7 has a plate spring 12 extending from the base 11 in the center thereof, and support portions 13 are integrally formed extending from the base 11 on both sides thereof. A hole 14 for the mounting pin 9 is formed in the base 11 and both support parts 13, and a hole 15 is formed in the free end of the leaf spring 12.
is formed. The spacer plate 6 is for attaching the plate material 7 to the yoke 1 at intervals corresponding to its thickness, and has a notch 16 at a portion corresponding to the leaf spring 12, and supports 17 on both sides of the notch 16. is formed integrally extending from the base 18.
Mounting pins 9 are attached to the base 18 and both support parts 17.
A hole 19 is provided for this purpose. In the hole 15 of the leaf spring 12, as shown in FIGS. 1 and 2,
A movable yoke 20 made of magnetic material is fixed. The rear part of the movable yoke 20 is inserted into the center hole of the front yoke 1 and magnetically attracted to the front end surface of the center yoke 4, and at this time, the leaf spring 12 is biased rearward against its own spring force. be done. Further, the front portion of the movable yoke 20 projects forward from an opening 21 at the center of the front surface of the support plate 8. At the front part of the movable yoke 20, a fifth
As shown in the figure, a split groove 22 is formed, and this split groove 2
The lower end of a plate-shaped printing hammer 23 is clamped to 2. The upper end of the printing hammer 23 has a striking surface 2.
4 is formed, and this striking surface 24 is connected to a rotating drum 27 via an ink ribbon 25 and a recording medium 26.
is facing. The rotating drum 27 is the recording medium 2
6, and has a plurality of protrusions 28 extending in the axial direction on its outer peripheral surface, and these protrusions 28 and the striking surface 24 face each other so as to substantially intersect with each other. . The protrusion 28 can change its intersecting position in the vertical direction with respect to the striking surface 24 by rotation of the rotating drum 27, and the striking surface 24 can be changed by the spacing of a carriage (not shown) on which the support plate 8 is mounted. The cross position can be changed laterally with respect to the projection 28. Note that 8a is an opening window provided in the support plate 8, and is opposed to the root portion of the leaf spring 12.

In FIG. 2, the magnetic flux from the permanent magnet 2 passes through the front yoke 1, the rear yoke 3, the center yoke 4, and the movable yoke 20 as shown by the arrows. is magnetically attracted to the front surface of the center yoke 4 against the When a current is applied to the coil 5 so as to cancel the magnetic flux, the movable yoke 20 is released from attracting the center yoke 4, and is therefore moved forward by the spring force of the spring portion 12. For this purpose, the printing hammer 23 also moves forward, and its striking surface 24 impulsively presses the ink ribbon 25 and the recording medium 26 against the protrusion 28 of the rotating drum 27, thereby causing the recording medium to strike the recording medium at the intersection of the striking surface 24 and the protrusion 28. A dot is formed at 26. Dust that has entered between the leaf spring 12 and the support plate 8 is discharged from the opening window 8a by the air flow when the leaf spring 12 moves forward.

As described above, according to the present invention, even if dust, printing paper powder, ink scum, etc. enter between the leaf spring and the support plate, it is discharged through the opening window, and no dust or the like accumulates between the two. Therefore, stable printing operation can be continued for a long period of time.

The above embodiment is an example in which the present invention is applied to a cross hammer type printer head, but it goes without saying that the present invention can also be applied to other types of printers.

[Brief explanation of drawings]

The drawings show one embodiment of the present printer head, in which Fig. 1 is a front view thereof, Fig. 2 is a sectional view thereof, Fig. 3 is a front view of a leaf spring, and Fig. 4 is a view of a spacer plate. The front view and FIG. 5 are cross-sectional views of the movable yoke. 8... Support plate, 8a... Opening window, 23... Printing element (hereinafter referred to as hammer).

Claims (1)

[Scope of utility model registration request] An arm-shaped leaf spring having a printing element at its tip and driven electromagnetically is fixedly connected to a support plate at its base, and an opening window is formed in the support plate at a position slightly above the base. A printer head featuring: