JPH0466193B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention biases a plate spring using a permanent magnet, and conducts electricity to an electromagnet provided in the magnetic path of the permanent magnet to cancel the magnetic field of the permanent magnet, thereby producing a biased plate. This invention relates to a print head for a dot printer which releases a spring and drives a print wire by the leaf spring.

As a printing head for a wire dot printer, there is one shown in Japanese Utility Model Application No. 53-41116. In this head, one end of the magnet part consisting of a pole piece and a coil is supported by an arm, the middle part is opposed to the pole piece at the bent end of this arm, and the other end is a thin plate with a printing wire protruding from it. An armature is provided, a thick plate-shaped movable iron piece is provided on the armature at a position corresponding to the pole piece, and a thick plate-shaped fixed iron piece is provided on the arm via the armature. When the coil is energized, the movable iron piece is magnetically attracted to the pole piece. Therefore, the armature is also attracted, and the printing wire protrudes and collides with the platen, printing characters on the printing paper.

However, in such a magnetic attraction type print head, the print wire protrudes in the direction in which the movable iron piece is attracted, so when the movable iron piece collides with the pole piece or not, the print wire prints characters on the printing paper. Therefore, the armature in its free state will cause large vibrations due to the inertial force of the movable iron piece. Furthermore, if the movable iron piece collides with the pole piece, the vibration of the armature may be amplified by the repulsive force.

The present invention provides a print head that can suppress such vibrations, and will be described in detail below with reference to the drawings.

FIG. 1 is an exploded perspective view showing one embodiment of the present invention. In the figure, 1 is a first plate forming a common magnetic path, 2 is N cores (N=2, 3, 4...) fixed to the upper surface of the first plate 1, and 3 is a first plate that forms a common magnetic path.
4 is a ring-shaped permanent magnet fixed to the upper surface of the first plate 1; 4 is a magnet coil fitted to the N cores 2; 5 is fixed to the upper surface of the ring-shaped permanent magnet 3 having a screw hole 5a; 6 is a spacer having a hole 6a in a plate material having a thickness equal to the desired gap; 7 is a spacer having N divided pieces 7a divided centripetally so that the outer peripheral surfaces are connected in a ring shape; a leaf spring having a hole 7b provided in the peripheral edge and laminated on the spacer 6; 8 an armature fixed to the upper surface of the divided piece 7a; 9 a printed wire fixed to the tip of the armature 8; Reference numeral 10 denotes a yoke plate 11 having a hole 10a and a groove 10b and laminated on the plate spring 7 to form a magnetic path between the ring-shaped permanent magnet 3 and the armature 8.
is a guide hole 1 for guiding the printed wire 9.
1a, and holes 11b and 11c, the guide frame is stacked on the yoke plate 10; 12 is the spacer 6, the leaf spring 7, and the yoke plate 10;
A mounting screw 13 for mounting the guide frame 11 to the second plate 5 in a stacked state is an oil felt.

An assembly method for the above structure will be explained. First, N cores 2 are fixed to the first plate 1, and magnetic coils 4 are fitted to each of the N cores 2.Next, a ring-shaped permanent magnet 3 is fixed to the first plate 1, and this A second plate 5 is fixed to the ring-shaped permanent magnet 3, and an oil felt 13 is further inserted to form a first assembly. Also N
Each of the printed wires 9 is fixed to a different armature, and each armature 8 is fixed to the upper surface of the N divided pieces 7a of the leaf spring 7 to form a second assembly. Next, the upper surface of the second plate 5 or the core 2 of the first assembly is
The upper end surface is polished so that the upper surface of the second plate 5 and the upper end surface of the core 2 are flush with each other. Spacer 6, second assembly and yoke plate 1 are placed on top of this finished second assembly.
0 and the guide frame 11 are sequentially stacked, and while inserting a clamping tool such as tweezers into the hole 11c of the guide frame 11 and pinching the printed wire 9, the printed wire 9 is attached to the guide frame 1.
1 into the guide hole 11a. After that, tighten the mounting screws 12 into holes 11b, 10a, 7b and 6a.
The spacer 6, the second assembly, the yoke plate 10, and the guide frame 11 are mounted on the second assembly in a stacked state by screwing them into the screw holes 5a through the screw holes 5a.

Therefore, the split piece 7a of the leaf spring 7 has a flexible portion between the mounting portion of the armature 8 and the outer edge of the yoke plate 10.

FIG. 2 is a sectional view showing the embodiment assembled as described above, cut in half, and the same elements are given the same reference numerals.

Next, the operation of the embodiment will be explained with reference to FIG. 2. First, when the magnet coil 4 is not energized, the armature 8 is attracted to the upper end surface of the core 2 by the magnetic force of the ring-shaped permanent magnet 3, so that the flexible portion of the divided piece 7a is bent and biased, and the armature 8 is biased toward the core 2. It is adsorbed. At this time, the magnetic flux of the ring-shaped permanent magnet 3 is as follows: ring-shaped permanent magnet 3 - second plate 5 - spacer 6 - plate spring 7 - yoke plate 10 - armature 8 - plate spring 7 - core 2
It passes through a magnetic path: - first plate 1 - ring-shaped permanent magnet 3. Next, when the magnetic coil 4 is energized, the magnetic flux generated by the magnetic coil 4 cancels the magnetic flux generated by the ring-shaped permanent magnet 3, so that the divided piece 7a, which has been biased toward the core 2, is released from the core 2. Therefore, the print wire 9 fixed to the armature 8 protrudes from the guide frame 13 and strongly presses an ink ribbon (not shown) against the printing paper, thereby making it possible to print dots on the printing paper.

Then, as shown in Fig. 3, the yoke plate 1
Since the plate width WB of the divided piece 8a is larger than the groove width WA of 0, the bent portion of the divided piece 7a gradually comes into contact with the yoke plate 10. Therefore, the divided piece 7a
stops rapidly, with almost no extra vibration due to repulsion.

Further, it goes without saying that the first plate 1, second plate 5, spacer 6, leaf spring 7, armature 8, and yoke plate 10 are made of a ferromagnetic material such as iron.

As described above in detail, according to the embodiment of the present invention, one end of the printed wire is fixed to the armature, and the plurality of divided pieces obtained by dividing the printed wire in a centripetal manner so that the outer periphery is connected in a ring shape. Since the armature is fixed to the leaf spring, the armature can be made smaller and the number of parts can be reduced. Since the yoke plate is provided with a groove that is smaller than the width of the leaf spring and larger than the width of the armature fixed to the leaf spring, there is no need to separately provide a stopper for the armature, and there is no need to provide a separate stopper for the armature. This has the effect of reducing excess vibration.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing one embodiment of the present invention, FIG. 2 is a sectional view showing the embodiment shown in FIG. 1 cut in half, and FIG. FIG. 4 is an enlarged view of a part of the embodiment shown in FIG.
FIG. 3 is a perspective view of a portion of the embodiment shown in FIGS. DESCRIPTION OF SYMBOLS 1...First plate, 2...Core, 3...Ring-shaped permanent magnet, 4...Magnetic coil, 5...
Second plate, 5a...screw hole, 6...spacer, 6a...hole, 7...plate spring, 7a...divided piece, 7b...hole, 8...armature, 9...printed wire, 10... ...Yoke plate, 10
a, 10b...Groove, 11...Guide frame, 1
1a...guide hole, 11b and 11c...hole,
12...Mounting screw, 13...Oil felt.

Claims (1)

[Scope of Claims] 1. Biased by a ring-shaped permanent magnet, divided pieces of a leaf spring, which are divided centripetally so that the outer circumferential parts are connected in a ring shape, are biased by energizing the electromagnet to cancel the magnetic field of the permanent magnet, and biased. In a print head for a dot printer, which releases the leaf spring in the state and drives the print wire, the flexible part of the split piece contacts the yoke on the side from which the print wire protrudes, which is opposite to the core of the electromagnet with the leaf spring in between. A printing head for a dot printer, characterized in that a plate is provided, and the yoke plate has a groove smaller than the width of the divided piece into which an armature fixed to the divided piece is inserted.