JPH04216957A - Impact dot head - Google Patents

Abstract

PURPOSE:To provide a small-sized high speed impact dot head reduced in power consumption and heat generation. CONSTITUTION:The armature 6 of an impact dot head is formed from a permanent magnet and the magnetic polarity of the surface opposed to the permanent magnet of the armature 6 is made opposite to that of the adjacent armature. Since the repulsive force of the permanent magnet in a magnetic field is utilized by constituting the armature corresponding to each core of the permanent magnet, even when the force of a spring is smaller than that of a conventional spring, equal or more printing force and high speed properties are obtained. Further, the permanent magnet becomes unnecessary and miniaturization and cost reduction are achieved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of an impact dot head.

0002

[Prior Art] In the conventional technology, as shown in FIG. 5, a core portion 1-a or a base plate 1 including the core is molded from a magnetic material, and a disk-shaped or ring-shaped permanent magnet 2 is bonded to the base plate 1. , countersunk ring-shaped magnetic material so-called yoke plate 3
are joined to form a base core unit so as to sandwich the permanent magnet 2, and the armature 6 facing each core part 1-a and kept at a certain position by the spring force of the spring 8 is connected to the permanent magnet 2.
The magnetic flux ΦC attracts the spring 8 to the core portion 1-a in an eccentric manner.

By passing the current i shown in FIG. 3(a) through the magnet coil 7, the magnetic flux ΦD shown in FIGS. 3(b) and 5 is generated, which reduces the magnetic flux ΦC of the permanent magnet 2, and the resulting core The suction force acting between the part 1-a and the armature 6 is the suction force fD shown in FIG. 3(c). The force acting on the armature 6 is the difference between the spring force of the spring 8 and the force F in the direction in which the armature 6 and the lever 5 print wire protrude.
b is shown in FIG. 3(d), and it was known that the tip of the printing wire 10 traces a trajectory shown in FIG. 3(e) and collides with the printing medium to form a dot.

0004

[Problem to be solved by the invention] However, when the impact dot head is configured as described above, printing power can be increased;
In order to increase the speed, it is necessary to increase the spring force, and it is also necessary to increase the suction force to attract the amateur to the core. If the base core is formed as described above, permanent magnets can only be ring-shaped or disc-shaped and oriented in the transverse magnetic field. The volume must be increased to a certain extent, and the impact dot head cannot be made smaller. Furthermore, since a common permanent magnet is used for each magnetic circuit corresponding to each core, the mutual influence of each magnetic circuit is large, and in order to obtain sufficient printing power, the input energy must be increased, and the input energy must be increased further. This causes problems such as the coil's heat generation increases and the resistance of the coil increases with the heat generation, making it impossible to input input, resulting in insufficient printing power and insufficient performance. An object of the present invention is to compensate for these drawbacks and provide an impact dot head that is small, high speed, consumes low power, and generates little heat.

[0005]

[Means for Solving the Problems] In order to solve the above problems, an impact dot head according to the present invention is characterized in that the armature is constructed of a permanent magnet.

[0006] Furthermore, the armature is characterized in that the magnetic polarity of the surface facing the electromagnet of the armature is opposite to that of the adjacent armature.

[0007]

[Operation] The impact dot head configured as described above uses the attractive force and repulsive force generated by the combination of the permanent magnet and the magnetic pole of the electromagnet in the magnetic circuit consisting of the armature, yoke, and electromagnet to increase the spring force of the spring. Even if it is small, it can obtain the force necessary for printing and high-speed drive. Spring force can be reduced. By not using a ring-shaped permanent magnet, the spring and base unit can be made smaller. In addition, by making the magnetic circuits independent, it is possible to suppress the mutual influence of each magnetic circuit, and sufficient printing power can be obtained even with small energy, resulting in a compact, high-speed, impact dot head with low power consumption and low heat generation. .

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of an impact dot head according to a first embodiment of the present invention. In the figure, the armature 6 is composed of a permanent magnet, has a lever 5 and a printing wire 10 fixed to its tip, and is connected to a leaf spring 8 at the other end, and the printing wire 10 is guided and held by a wire guide 12. The leaf spring 8 is sandwiched and fixed between the spring pressing plate 9 and the side yoke 4, and these, the yoke plate 3, and the base plate 1 are fixed in a laminated state.

[0009] The armature 6 is attracted to the opposing core 1-a while bending the plate spring 8 to which it is fixed by the attractive force of the magnetic flux of the permanent magnet. Core 1-a is base plate 1
A plurality of magnet coils 7 are disposed substantially circumferentially on the armature 6, facing the armature 6, and a magnet coil 7 is wound around the core 1-a. Both ends of the winding of the magnet coil 7 pass through holes or slits provided in the base plate 1 and are soldered to the substrate 17.

An inner ring 11 is disposed at a position where it contacts the inner circumference of the base plate 1, and the outer circumference of the inner ring 11 has a shape that follows the outer shape of the magnet coil 7. A heat transfer member 13 having a cylindrical convex portion is in contact with the outer circumferential surface of the cylindrical convex portion and a circumferential surface of the inner circumferential ring 11 at the inner circumferential portion of the inner circumferential ring 11 , and a heat sink 15 is disposed on the inner circumferential portion of the inner circumferential ring 11 . is in contact with. The heat transfer member 13 and the heat sink 15 are fixed to the base plate 1 with screws 16.

Next, the operation will be explained. As shown in Fig. 2, the magnetic flux ΦA of the permanent magnet of the armature 6 exerts an attractive force on the armature 6 and the core 1-a, causing the armature 6 to be attracted to the core 1-a while distorting the leaf spring 8 fixed to the armature 6. are doing. In this state, the magnetic flux Φ is applied to the magnet coil 7.
A current i is caused to flow in a direction in which magnetic flux ΦB is generated in the opposite direction to A.

FIG. 3(a) shows the current i flowing through the magnet coil 7.

FIG. 3(b) shows the magnetic flux ΦA due to the permanent magnet of the armature 6 and the magnetic flux Φ due to the current i of the magnet coil 7.
B, and the respective flow directions are the directions shown in FIG.

FIG. 3(c) shows the force acting between the armature 6 and the core 1-a due to the magnetic fluxes ΦA and ΦB. Until time t0 when the magnetic flux ΦB is not generated, an attractive force fA due to the magnetic flux ΦA is generated and the armature 6 and core 1-a is adsorbed. As time and current i pass, the attractive force fB between the armature 6 and the core 1-a decreases due to the magnetic flux ΦB, and the spring force of the spring 8 gradually overcomes the armature 6, the lever 5, and the printing wire 10.
starts working.

At the current ia in FIG. 3(a) where a magnetic flux ΦB of the same magnitude as the magnetic flux ΦA is generated, the armature 6 and the core 1-a
The armature 6, the lever 5 fixed to its end, and the printing wire 10 fixed to the lever 5 are guided to the wire guide 12 by the strain energy stored in the leaf spring 8 without any suction force acting between them. However, when a force acts in a direction in which the other end of the printing wire 10 protrudes onto the surface of the paper (not shown), and the current flowing through the magnet coil 7 increases, the printing wire 10 The force increases in the direction in which 10 protrudes, and the printing wire 10 is further accelerated.

FIG. 3(d) shows the force Fb which is the resultant force of the force due to the magnetic fluxes ΦA and ΦB acting on the armature 6, the lever 5, and the printing wire 10, and the spring force. Print wire 1 by Fb
The other end of the printing wire 10 traces a trajectory Xa shown in FIG. 3(e), and the other end of the printing wire 10 collides with a ribbon and paper (not shown) to form dots on the paper surface. Printing wire 1 after dot formation
The armature 6 is again attracted and held by the core 1-a by the repulsive force of the armature 6 during the collision and the attraction force of the permanent magnet of the armature 6.
One printing process is completed.

In FIG. 3(e), when comparing the trajectory Xa of the printing wire 10 according to the embodiment of the present invention with the trajectory Xb of the conventional example shown in FIG. 5, one printing process is completed in a short time with the same current i. The embodiment of the present invention is suitable for speeding up.

FIG. 4(a) is a view of the armature 6, leaf spring 8, and lever 5 of the second embodiment of the present invention as seen from the direction of the paper surface (not shown), and FIG. 4(b) is a diagram of the second embodiment of the present invention. It is a sectional view of an example. In this embodiment, as shown in FIGS. 4(a) and 4(b), the permanent magnets used in the armature 6 are arranged so that adjacent ones have opposite magnetic poles, and two or more When driving a magnet coil 7, as shown in Fig. 4(b), the magnetic flux ΦB of the adjacent magnet coil 7 matches the magnetic flux ΦB of its own magnet coil 7, which makes it easier for the magnetic flux to pass through, thereby reducing the influence of mutual interference. is decreasing.

[0019]

[Effects of the Invention] In the impact dot head, the armature corresponding to each core of the present invention is constructed with a permanent magnet, so that the repulsive force of the magnet in the magnetic field is utilized, so the spring force of the spring is lower than that of the conventional spring. Even if the spring force is small, the same or higher printing force and high speed can be obtained, the printing force no longer depends only on the spring force, the spring can be made smaller while maintaining high speed, and the core and base plate The base unit, which consists of a yoke, a magnetic coil, and a magnet coil does not use a permanent magnet, so it can be made smaller, and the impact dot head can be made smaller while maintaining high speed. Also,
By configuring the armature's permanent magnets to be independent and have opposite polarity to adjacent magnets, it is possible to reduce magnetic interference, which is mutual interference between each magnetic circuit, and improve input efficiency when driving multiple pins of an impact dot head simultaneously. This has the effect of reducing the power consumption and heat generation of the impact dot head.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an impact dot head according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing the flow of magnetic flux in the first embodiment of the present invention.

FIG. 3 is a diagram showing temporal changes in current, magnetic flux, attraction force, and displacement of the impact dot heads of the first embodiment of the present invention and the conventional example.

FIG. 4 is a cross-sectional view showing the magnetic poles of the permanent magnet of the armature as seen from the nose side of the impact dot head according to the second embodiment of the present invention, and a longitudinal cross-sectional view showing the magnetic poles of the permanent magnet of the armature.

FIG. 5 is a cross-sectional view showing the structure of a conventional impact dot head and the flow of magnetic flux.

[Explanation of symbols]

2. ．． ．． permanent magnet 3. ．． ．． yoke plate 4. ．． ．． side yoke 5. ．． ．． lever 6. ．． ．． amateur 7. ．． ．． magnet coil

Claims (2)

[Claims] 1. Driving a armature facing a plurality of electromagnets each including a plurality of cores and a coil wound around each core, a lever fixed to the armature, and a printing wire fixed to the lever, An impact dot head that forms dots on a printing medium by impact force, characterized in that the armature is formed of a permanent magnet. 2. The impact dot head according to claim 1, wherein the magnetic polarity of the surface of the armature facing the electromagnet is opposite to that of an adjacent armature.