JPH0222285Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an impact printer head that forms characters and the like using a dot matrix.

The movable yoke at the end of the cantilevered leaf spring is magnetically pulled backwards, and the magnetic force is canceled by energizing the coil, thereby releasing the movable yoke and applying the spring force of the leaf spring. Release type printers in which a printing hammer is driven by a printer are well known. Since the movable yoke moves in an arc around the support portion of the leaf spring, when the movable yoke is drawn toward the center yoke, its rear end surface locally contacts the front end surface of the center yoke. This has led to a decrease in abrasion resistance, printing power, or magnetic efficiency. When the movable yoke is drawn to the center yoke, in order to bring the rear end surface into surface contact with the front end surface of the center yoke, (i) the leaf spring should be installed diagonally;

(ii) Bending the leaf spring.

(iii) Machining the front end surface of the center yoke diagonally.

(iv) Attach the entire magnetic circuit section diagonally.

Possible methods include: However, in both cases, assembly becomes troublesome and costs increase.

The present invention is designed to bring the rear end face of the movable yoke and the front end face of the center yoke into face-to-face contact without impairing assemblability or high-speed response, and one embodiment thereof will be described below.

In Fig. 1 and Fig. 2, a front yoke 1, a permanent magnet 2, a rear yoke 3, a center yoke 4, a coil 5
A magnetic circuit device is constructed by the following. The front yoke 1 has a substantially disk shape, and has a center hole 1a in its center. The permanent magnet 2 has an annular shape, and a bottomed cylindrical rear yoke 3 is located on the back side of the permanent magnet 2. The front yoke 1, the permanent magnet 2, and the rear yoke 3 are stacked on top of each other via a set screw R in the form of a sandwich arch. . A center yoke 4 is connected at right angles to the center of the bottom of the rear yoke 3, forming a center notch 1a of the front yoke 1.
It is extending towards. A release coil 5 surrounding the center yoke 4 is inserted into a hollow portion of the rear yoke 3.

A spacer plate 6 , a leaf spring 7 , and a support plate 8 are fixed to the front surface of the front yoke 1 via attachment pins 9 . The support plate 8 is bent into an L-shaped cross section, and a portion of the magnetic circuit device protrudes from a notch 10 at that angle. As shown in FIG. 3, the leaf spring 7 is in the form of a flat tongue, and mounting portions 12, 12 are integrally formed from the base 11 of the leaf spring 7, and are located on both sides of the leaf spring 7. A hole 13 for the attachment pin 9 is formed in the substrate 11 and the attachment parts 12, 12, and a hole 14 is also formed in the tip of the leaf spring 7. The spacer plate 6 is provided to provide a gap between the plate spring 7 and the front yoke 1 corresponding to the thickness of the spacer plate.
5, with mounting parts 16, 16 on both sides of the base 1.
It is integrally formed to extend from 7. and base 1
7 and mounting portions 16, 16 have holes 18 for mounting pins 9.
is drilled. There is a fifth hole in the hole 14 of the leaf spring 7.
The illustrated movable yoke 19 is fixedly fixed therethrough. A split groove 19a is formed in the front portion of the movable yoke 19, into which a lower end portion of a plate-shaped printing hammer 20 is inserted and fixed. The rear part of the movable yoke 19 faces the center yoke 4 through the center hole 1a of the front yoke 1, and is magnetically attracted to the center yoke 4 against the spring force of the leaf spring 7 during normal times. . Then, by energizing the coil 5, the magnetic flux from the permanent magnet 2 is canceled out, so that the movable yoke 1
9 is released, and the movable yoke 19 and printing hammer 20 move forward by the spring force of the leaf spring 7.

In the present invention, the permanent magnet 2 is formed to have a substantially wedge-shaped cross-section as shown in FIG. That is, the rear surface 2a of the permanent magnet 2 is inclined at an angle θ, so that the thickness of the permanent magnet 2 is smaller on the support side (lower part) of the leaf spring 7 than on the opposite side (upper side). . Note that 2b is a hollow hole,
2c is a through hole for screw R. The inclination angle θ is the second
It is approximately equal to the receding angle of the leaf spring 7 (movable yoke 19) in the illustrated state. As a result, the rear yoke 3 that is joined to the rear surface of the permanent magnet 2 is mounted upward by an angle θ, and the center yoke 4 is also attached at an angle θ corresponding to the angle θ.
It will be positioned upwards. Therefore, when the movable yoke 19 is pulled rearward as shown in the second figure, its rear end surface makes surface contact with the front end surface of the center yoke 4.

According to the above-mentioned structure of the present invention, the permanent magnet has a wedge-shaped cross section in which the thickness of the fixed side of the leaf spring is smaller than the thickness of the opposite side, and the angle formed by the front and rear surfaces of the permanent magnet is Since the receding angle of the leaf spring is approximated when the movable yoke is attracted to the center yoke, the movable yoke and the center yoke can be brought into face contact when the movable yoke is attracted to the center yoke, improving magnetic efficiency and durability. It can enhance your sexuality. Furthermore, permanent magnets can be formed by simply changing the mold during sintering, and there is no need to change conventional assembly procedures or jigs, so this can be done at a very low cost. Furthermore, since the leaf spring can be left as a flat spring, the response speed of the printing hammer will not be reduced.

[Brief explanation of drawings]

The drawings relate to an embodiment of a printer head to which the present invention is applied, 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 spacer. FIG. 5 is an enlarged top view of the movable yoke, and FIG. 6 is a sectional view of the permanent magnet. 1...Front yoke, 2...Permanent magnet, 2a...Rear surface of permanent magnet, θ...Inclination angle, 3...Rear yoke,
4... Center yoke, 5... Coil, 7... Leaf spring, 19... Movable yoke, 20... Printing hammer.

Claims (1)

[Scope of utility model registration request] Front and rear yokes joined to both sides of a hollow annular permanent magnet, a center yoke fixed to the center of the rear yoke and extending toward the center hole of the front yoke, and an outer peripheral portion of the center yoke. a magnetic circuit device having a surrounding release coil; a leaf spring cantilevered in front of the magnetic circuit device; a leaf spring fixed to the end of the leaf spring through the center hole of the front yoke; a movable yoke that is magnetically attracted to the front end surface of the central yoke against the spring force of the leaf spring in normal times and is released from the magnetic attraction by energizing the coil; The permanent magnet has a wedge-shaped cross section in which the thickness of the fixed side of the leaf spring is smaller than the thickness of the opposite side, and the angle formed by the front and rear surfaces of the permanent magnet is the movable magnet. A printer head characterized in that the receding angle of the leaf spring is approximated when the yoke is attracted to the center yoke.