JPH0464453A - Spring charge-type printing head - Google Patents

Abstract

PURPOSE:To raise a printing speed by using a ring spring in which the expansion of an elastic member is utilized as a spring means. CONSTITUTION:In a stop state, an armature 2 is attracted by a core 4 by a magnetic flux produced by a permanent magnet 3. At this time, a ring spring 12 is pulled in an axial direction and produces a small elongation within its elastic limit. After that, when an electric current flows to a demagnetizing coil 5 upon issuance of a printing instruction, the magnetic flux by the permanent magnet 3 is de-energized. Then, the armature 2 is separated from the core 4 by the restoring force of the elongated ring spring 12, and a printing wire l impacts paper on a platen through an ink ribbon to make printing thereon. In this manner, printing can be enhanced in speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a spring-charged print head, and particularly to a spring-charged printhead used in a serial impact dot matrix printer.

[Conventional technology]

Conventionally, this type of spring-charged print head consists of an armature for driving the print wire, a permanent magnet that attracts this armature, a degaussing coil that cancels the magnetic flux from this permanent magnet to the armature, and the attraction force of the permanent magnet. The armature is configured to have a spring means that constantly biases the armature in the opposite direction.

By the way, as this spring means, a leaf spring system, a cross spring system, and a torsion spring system, each of which is shown in perspective view in FIGS. 4, 5, and 6, are employed.

The leaf spring method shown in Fig. 4 is the most commonly used one, in which one end of a leaf spring 43 with a plate thickness of around 0.5 mm is fixed (fixed end 44), and an armature 42 is attached to the free end by brazing or laser beam. The structure is such that they are joined by welding or the like, and the deflection of the leaf spring 43 is used as the spring means.

The cross spring system shown in FIG. 5 has two systems of springs. One is a main spring 53 corresponding to the above-mentioned leaf spring, one end of which is fixed (fixed end 55), and the other end of which is joined to an armature 52 by brazing or the like.

The other spring is a vertical spring 54, which intersects the main spring 53 at almost a right angle and is also fixed at one end (fixed end 56).
, the other end is joined to the armature 52. (Although the vertical spring 54 shown in FIG. 5 is plate-shaped, rod-shaped ones have also been proposed.) In this system, the vertical spring 54 functions in the lateral direction of the main spring 53 (in the longitudinal direction of the plate). The main spring 53 is also used as a spring means to increase the rigidity of the main spring 53 (perpendicular direction).

The torsion spring system shown in Figure 6 uses armature 6
A torsion spring 63 having a circular cross section is connected to one end of the torsion spring 6 by brazing or the like.
The other end of the torsion spring 63 is joined to the support member 64 by brazing or the like, and the other end of the torsion spring 63 is joined to the support member 64 by brazing or the like. torsion spring 63
Both ends of the torsion spring 63 are joined to the armature 62 and the support member 64, respectively, so when the armature 62 receives a suction force from a yoke (not shown), the torsion spring 63 is twisted. In this way, this method uses the torsion of the member as a spring means.

[Problem to be solved by the invention]

In the above-mentioned conventional spring-charged print head, the most well-known type of spring means is the leaf spring type, which has low rigidity in the direction of movement of the print wire, resulting in a long contact time between the print wire and the ribbon. , has the disadvantage that it is not suitable for high speed. Further, although the cross spring system improves the drawbacks of the leaf spring system by the action of vertical springs, as shown in FIG. 5, it has the drawbacks of being complicated in structure and generally high in cost. Furthermore, in order to control the spring constant in the torsion spring method, the torsion spring is processed into a drum shape, and the stress is increased, which requires more advanced manufacturing technology and quality control than before.

In addition, there are many joints between members, and it is difficult to form an integral structure for bins with 24 dots or more due to the structure, resulting in a very high cost.

[Means to solve the problem]

The spring-charged print head of the present invention includes an armature for driving a print wire, a core equipped with a permanent magnet that attracts the armature, a degaussing coil that cancels the magnetic flux from the permanent magnet to the armature, and spring means for constantly biasing the armature in opposite directions;
A fulcrum member disposed on the end surface of the core and forming a fulcrum of the armature, a notch provided on the side opposite to the printing wire side with respect to the fulcrum of the armature, and an annular elastic spring that abuts the notch of the plurality of armatures. and a support member that supports the elastic spring member.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention.

The embodiment shown in FIG. 1 includes an armature 2 for driving a printing wire 1, a permanent magnet 3 for attracting and driving the armature 2, a core 4 connected to the permanent magnet 3 via a yoke, and a core 4 connected to the permanent magnet 3 through the armature 2. Degaussing coil 5 that cancels the magnetic flux to
and a ring spring 12 that constantly biases the armature 2 in a direction opposite to the attractive force of the permanent magnet 3.

To explain the above configuration in more detail, the yoke 7 having a U-shaped cross section has a ring yoke 8 connected to one end thereof via a permanent magnet 3. On the other hand, a fulcrum member 9 is joined to the other end of this U-shaped yoke 7, and a notch Bll is provided on the side opposite to the printing wire 1 with respect to the notch 10 provided in the armature 2. A ring spring 12 with a circular cross section is provided as a spring means in the cutout Bll. Further, the ring spring 12 is supported by the support member 13 so as to be always in contact with the notch Bll.

FIG. 2 is a partial detailed view of one printing mechanism shown in FIG. 1, and the print head is constructed by arranging a plurality of printing mechanisms, such as 24, in a radial pattern. FIG. 2(a) is a front view, in which the armature 2 having a notch AIO is placed on a fulcrum member 9 provided at the tip of the core 4 (not shown). Further, another notch B11 provided in the armature 2 has an annular ring spring 12 mounted thereon.

Further, the ring spring 12 is held down by a support member 13 shaped like a letter 0 and having a space on the opposite surface of the core 4 facing the armature 2. FIGS. 2(b) and 2(C) are a longitudinal sectional view and a bottom view of FIG. 2(a), respectively.

FIG. 3 is a diagram for explaining the operation of the ring spring 12 of the embodiment shown in FIG. FIG. In the stopped state, the armature 2 is attracted to the core 4 by the magnetic flux generated by the permanent magnet 3. At this time, the ring spring 12 is pulled in the axial direction and causes a slight elongation within the elastic limit. Microscopically, ring spring 1
2 acts like a rubber band. Next, when a print command is issued and current flows through the degaussing coil 5, the magnetic flux caused by the permanent magnet 3 is canceled out. So armature 2 is ring spring 1
The printing wire 1 separates from the core 4 due to the force of returning the elongation to its original state, and the printing wire 1 hits the paper on the platen via the ink ribbon to perform printing. Figure 3 (C) and (
d) shows a front view and a side view in a printed state, respectively. When printing is completed, the armature 2 is again attracted to the core 4 by the magnetic flux generated by the permanent magnet and comes to a stopped state.

〔Effect of the invention〕

As explained above, the present invention is simpler than the conventional cross spring method or torsion spring method by using a ring spring whose spring means is the expansion and contraction of an elastic member.
This has the effect of providing an inexpensive, high-speed spring-charged print head.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, FIG. 2 is a partial detailed view of FIG. 1, FIG. 3 is a diagram for explaining the operation of the ring spring in FIG. 1, FIG. 5 and 6 are perspective views of different conventional spring means, respectively. 1... Printing wire, 2, 42, 52.62... Armature, 3... Permanent magnet, 4... Core, 5...
Demagnetizing coil, 7... U-shaped yoke, 8... Ring yoke, 9... Support member, 10... Notch A, 11...
...Notch B, 12...Ring spring, 13.64...
- Support member, 43... Leaf spring, 53... Main spring, 5
4... Vertical spring, 63... Torsion spring.

Claims (1)

[Claims] An armature for driving the printing wire, a core with a permanent magnet that attracts the armature, a degaussing coil that cancels the magnetic flux from the permanent magnet to the armature, and the armature is always energized in the opposite direction to the direction of attraction of the permanent magnet. In a spring-charged print head used in a serial impact dot matrix printer, the print head includes a fulcrum member disposed on the end surface of the core and forming a fulcrum of the armature, and a side opposite to the printing wire side with respect to the fulcrum of the armature. 1. A spring-charged print head comprising: a notch provided in a plurality of armatures; an annular telescoping spring member abutting the notch of a plurality of armatures; and a support member supporting the telescoping spring member.