JPS6161864A - Printing head - Google Patents

Abstract

PURPOSE:To prevent as securely as possible a bending stress or a shearing stress from being exerted on a printing wire, by constructing a wire guide for the printing wire in such a form that a base end part of the wire can be maintained to be substantially straight. CONSTITUTION:In a wire dot printing head of the type in which an armature supported in a magnetic gap of a magnetic circuit by a spring is driven by switching ON and OFF the magnetic flux in the magnetic gap whereby a printing wire fixed to the armature is driven through an arm, guide holes provided in two guide plates 131, 132 on the base end side of the wire are matched rectilinearly to the base end part of the wire 10, while guide holes provided in three other guide plates 134-136 are so designed as to bend the wire 10 by a predetermined amount. Accordingly, the bending stress and shearing stress exerted on a connection part of the wire and the arm which part is most associated with strength problem can be minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a wire dot printer head, and particularly to a printer head having a suitable wire guide structure.

<Prior Art> Generally, a wire dot printer head uses a plurality of printing wires, and the printing ends of the printing wires are guided by a wire guide so that they are closely arranged in one row or two rows in a staggered manner. It has become so. Since the proximal end of the printing wire must be mechanically connected to the armature that is driven by the magnetic circuit, the proximal end of the printing wire must be as close as possible to the proximal end of the adjacent printing wire. This type of wire guide is necessary because the printing ends of the printing wire must be arranged closely as described above, but the printing wire must not move at high speed along the wire guide. Bending stress or shearing stress may occur in each part of the printing wire as it moves in the axial direction, causing breakage of the wire V, or such bending stress or shearing stress may cause damage between the base end of the printing wire V and the arm. The printing wire was easily peeled off from the arm, concentrating on the connection area. Further, the reaction force of the force applied to the printing wire acts on the wire guide, which causes wear of the hole in the wire guide that directly guides the printing wire, resulting in deterioration of printing quality.

<Problems to be Solved by the Invention> In view of the above-mentioned drawbacks of the conventional wire dot printer head, the main object of the present invention is to provide a suitable method to avoid applying bending stress and shear stress to the printing wire as much as possible. An object of the present invention is to provide a wire dot printer head having a wire guide structure capable of guiding a printing wire.

<Means for Solving the Problems> According to the present invention, an armature supported by a spring in a magnetic gap of a magnetic circuit is driven by intermittent magnetic flux in the magnetic gap. With this, in a wire dot printer head of a type that drives a printing wire fixed to the armature via an arm, a wire guide for guiding the printing wire substantially extends from the base end of the printing wire. This is achieved by providing a wire dot printer head that is characterized in that it is configured to be held straight.

By preventing the proximal end of the printing wire from being bent in any direction, bending stress and shearing stress applied to the connection between the printing wire and the arm, where strength is the most important issue, can be reduced. Since the printing wire can be miniaturized, breakage of the printing wire or separation from the arm can be effectively prevented.

<Embodiments> Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 shows a partially cut away printer head according to the present invention. A yoke 1 made of a magnetic material and a core member 2 made of a magnetic material having a required number of cores 2a spaced apart in the circumferential direction are screwed together by screws 6 so as to sandwich an annular permanent magnet 3 between them. has been done. Further, a leaf spring 5 is sandwiched between the yoke 1 and the annular permanent magnet 3, and an armature 4 is supported at the free end of the leaf spring 5. An arm 9 is fixed to the other end of the armature 4, and one end of a printing wire 10 is fixed to the free end of the arm 9. The printing wire 10 is attached to the yoke 1 by a screw 7.
It passes through a wire guide provided inside the head nose 11, and its tip reaches the free end surface 11a of the head nose. A solenoid 8 is wound around each of the cores 2a, and a Mla for receiving the armature 4 is cut in a portion of the yoke 1 facing the free end of the core 2a.

Therefore, as clearly shown in FIG. 2, the □ armature 4 is placed within a magnetic hub defined by the Vi end surface of the core 2a and the circular inner surface of the groove 1a. A groove 14 is formed in the armature 4 to reduce its inertial mass so as not to increase its magnetic flux density as much as possible.

When solenoid 8 is not energized, armature 4
is urged toward the free end side of the core 2a by the attractive force of the permanent magnet 3. At this time, when the solenoid 8 is activated in a direction that cancels out the effect of the permanent magnet 3, the armature 4 is elastically separated from the free end surface of the core 2a by the restoring force of the leaf spring 5. At this time, the printing wire 10 fixed to the armature 4 via the arm 9 protrudes from the TI end face 11a of the helad nose 11 and hits the ink ribbon (not shown) and the paper surface to perform the desired printing.

A ring 12 fixed to the outer periphery of the core member 2 is a permanent magnet 3
The magnetic internal resistance of the permanent magnet 3 is reduced by somewhat magnetically bridging the magnets, and when the solenoid 8 is energized in order to separate the armature 4 from the free end surface of the core 2a, the permanent magnet 3 is By adjusting the gap between the ring 12 and the outer periphery of the disc 1 as appropriate, the magnetic force of the permanent L1 is supplied to the solenoid 8 in order to cancel out the gravitational force of the permanent L1. It is possible to reduce the power consumption.

FIG. 3 conceptually shows a wire guide structure within a conventional helad nose 11. As shown in FIG. This wire guide structure is
It has five guides &141-145 provided at intervals along the axial direction of the printing wire 0, and has, for example, 16 holes 14-145 according to the number of magnetic circuits in the main body.
145 is bored in each guide plate. Print to Y71
In the guide plate 131 corresponding to the most proximal end of the guide plate 131, guide holes 141 are provided at equal intervals along one circumference in order to adapt to the configuration of the magnetic circuit. Guide holes 14 □ are arranged in the two-stage guide plate 13 □ in a substantially elliptical shape, and the printing wire 0 inserted through these guide holes passes through two more guide plates 13 , which are not shown.
The direction of the head nose 1 is changed by the guide holes 143 and 144 provided in the outermost guide plate 135 through the guide holes 145 provided in two rows in a staggered manner in the outermost guide plate 135.
It has reached the outer edge of 1.

4 and 5 show the configuration of a conventional type wire guide a, which is configured to gradually bend the printing wire 0 in order to reduce the stress applied to the printing wire 0 as a whole. Therefore, the bending moment MMa or the bending stress x'y or shear stress due to the shear force Px tends to concentrate at the connection between the arm and the printing wire 0.

6 and 7 show the structure of the wire guide based on the present invention, in which two guide plates 13 and 13 on the proximal end side are shown.
The guide holes provided in 2 are linearly aligned with the base end of the printing wire 0, and the guide holes provided in the other three guide plates 13 to 1 are aligned linearly with the base end of the printing wire 0.
The guide hole provided at 36 allows the printing wire 0 to be bent by the required m. If necessary, the number of guide plates can be increased to obtain the required bending suspension. In any case, since the guide holes provided in at least two guide plates on the proximal end side are linearly aligned with the proximal end of the printing wire 0, the printing wire 0 and arm 9 are the most problematic in terms of strength. Substantially no bending moment or shearing force is applied to the connection portion with the arm 9, and folding of the printing wire 10 or separation of the printing wire from the arm 9 can be effectively prevented.

The present invention is not limited to the above embodiments, and can be implemented with various modifications and changes.

For example, the wire guide 11 does not necessarily have to be composed of a plurality of stages of guide plates, but may have a guide member that is at least partially continuous.

Effect> As described above, according to the present invention, the portion of the printing wire on the proximal end side that is held straight is restrained from moving in a plane substantially perpendicular to the axial direction of the printing wire at at least two places. Therefore, substantially no bending moment or shearing force is applied to the proximal end of the printing wire. Therefore, the stress applied to the printing wire glue end, which is most problematic in terms of strength, can be reduced. Therefore, the peeling of the printing wire from the leaf 10 or the arm is effectively prevented, and the force acting between the guide hole of the proximal guide plate and the wire is reduced, so that wear of the guide hole is also effectively prevented. It can also have the effect of preventing

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side view of a wire dot printer head according to the present invention. FIG. 2 is a sectional view taken along the line ■--■ in FIG. 1. FIG. 3 is a perspective view that does not conceptually show the wire guide structure inside the herad nose. 4 and 5 are a side view and a front view, respectively, conceptually showing the structure of a conventional wire guide. FIGS. 6 and 7 are a side view and a front view, respectively, showing the conceptual structure of the wire guide according to the present invention. 1...Yoke 1a...Groove 1b...Periphery 2...Core member 2a...Core
3... Permanent magnet 4... Armature 5...
Leaf spring 6.7...Screw, 8...Solenoid 9
...Arm 10...Print Y V11...
・Head nose 12...Ring 13-135...
Guide plates 14 to 145...Guide holes 15...Groove Patent Applicant: NHK Spring Co., Ltd. Agent: Patent attorney Dai
Shima Yo - Figure 2 Figure 3

Claims (2)

[Claims] (1) A method in which an armature supported within a magnetic gap of a magnetic circuit by a spring is driven by intermittent magnetic flux within the magnetic gap, thereby driving a printing wire fixed to the armature via the arm. A wire dot printer head characterized in that a wire guide for guiding the printing wire is configured to keep a base end of the printing wire substantially straight. head. (2) The wire guide has a plurality of guide plates provided at intervals along the axial direction of the printing wire and each having a guide hole for guiding the printing wire, and The printer according to claim 1, wherein guide holes provided in at least two end-side guide plates are substantially linearly aligned with the base end of the printing wire. head.