JP3021910B2 - Print head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spring-charged magnetic shielding type print head mounted on a printer or the like for printing characters on a medium such as paper.

[0002]

2. Description of the Related Art A conventional print head generally has, for example, a structure shown in FIG. Hereinafter, the structure will be described with reference to FIG. The print head includes an electromagnetic drive unit including a yoke 2 in which coils 1 formed by winding a conductive wire such as copper are arranged in 24 circles and a magnet 3 having magnetic attraction, An armature 5 for holding a wire 4 is fixed in a cantilevered manner in the vicinity of the center in the form of a 24 cantilever beam in the form of a circular plate spring 6 fixed between a front plate 7 and an armature holder 8. Have been.

[0003] A predetermined space is provided between the yoke 2 and the armature 5, but the circular leaf spring 6 is normally bent by the magnetic attraction of the magnet 3, and the armature 5 is attracted to the yoke 2. It is in the state that was done. When the coil 1 is energized at the time of printing, the coil 1 is excited and the magnetic attraction of the magnet 3 is cut off via the yoke 2, so that the moment the bent circular plate spring 6 obtains the restoring force. Amateur 5 leaves York 2. At the same time, the printing wire 4 fixed to the circular leaf spring 6 protrudes in the direction opposite to the yoke 2 and hits the sheet via the ink ribbon to transfer the ink to the sheet, thereby performing printing.

FIG. 4 is a partial plan view of a print wire drive section of a print head, and FIG. 5 is a sectional view of a main part of the print wire drive section. The structure will be described below. Circular leaf spring 6
An outer peripheral fixing portion 6a screw-fixed between the front plate 7 and the amateur holder 8, a spring operating portion 6b acting as a spring when being attracted and opened by the electromagnetic force of the electromagnetic driving portion,
An armature 5 for holding the printing wire 4 is fixed by welding to an armature 5c. The plate spring 6 has a flat cross section as shown in FIG. The armature fixing portion 6c is generally fixed to the armature 5 by welding, and a nugget 9 formed at the time of welding protrudes from the upper surface of the leaf spring 6.

[0005]

In such a conventional leaf spring shape, since the nugget 9 of the armature fixing portion 6c protrudes from the upper surface of the leaf spring, it is necessary to allow a large escape of the leaf spring of the front plate 7. . When the thickness of the circular leaf spring 6 is increased in order to secure the spring force,
Since the mass of the leaf spring 6 increases, the response of the leaf spring 6 at the time of printing decreases and the weldability of the armature 5 decreases.

Accordingly, an object of the present invention is to provide a print head provided with a circular leaf spring which can solve the above-mentioned problems.

[0007]

According to the present invention, an upright portion is formed in a circular leaf spring, and an armature is fixed to a non-upright portion by welding.

[0008]

According to the above construction, the nugget does not protrude from the surface of the leaf spring, the thickness of the circular leaf spring is reduced, and the section modulus is increased by the upright portion, so that the spring force can be increased. .

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial plan view of a circular leaf spring showing an embodiment of the present invention, and FIG. 2 is a sectional view of a main part thereof. The overall configuration of this print head is the same as the conventional one shown in FIG. An outer peripheral fixing portion 6a screw-fixed between the front plate 7 and the amateur holder 8;
It comprises a spring operating portion 6b acting as a spring when attracted and opened by the electromagnetic force of the electromagnetic driving portion, and an armature fixing portion 6c which fixes the armature 5 holding the wire 4 in a cantilever manner by welding.

Before the circular leaf spring 6 is fixed to the armature 5 by welding, the armature fixing portion 6c and the spring operating portion 6b are convex (a), concave (b), and H-shaped as shown in FIG. (C) By forming a cross section having an upright portion a such as a + type (d), the section modulus is increased so as to obtain a large spring force. Pressing, etching, or the like can be applied as a forming method.

The leaf spring 6 thus formed is welded to the armature 5 to which the wire 4 is fixed. The welding between the leaf spring 6 and the armature 5 is performed by positioning the leaf spring 6 and the armature 5 and then spot welding a flat non-standing portion b with a laser welding machine or a spot welding machine. The relationship between the height tn of the nugget 9 generated at that time and the height te of the upright portion a is set such that tn <te. In printheads having different thicknesses of the leaf springs 6, the relationship of tn <te is satisfied, and the height ts obtained by subtracting te from the total height of the leaf springs 6 is set to be constant.

When the upright portions a are formed in the leaf spring 6, the thickness ts of the leaf spring 6 is made as thin as possible to reduce the weight, and at the same time, the sectional modulus is increased with a small cross-sectional area to provide a sufficient spring force. The nugget 9 generated by welding the armature 5 can be secured, and is lower than the upright portion a, so that the nugget 9 does not unnecessarily protrude.

[0013]

As described above, according to the present invention, since the upright portion is formed in the leaf spring, the section modulus for the same cross-sectional area increases, and the spring force can be increased, and the same spring force is obtained. For this purpose, the cross-sectional area of the circular leaf spring can be reduced, the weight can be reduced, and the printing frequency can be improved. Also, since the nugget generated during amateur welding is inside the upright part, the nugget does not protrude from the leaf spring,
The step of the front plate can be used only to escape the printing stroke.

[Brief description of the drawings]

FIG. 1 is a partial plan view of a circular leaf spring according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of the circular leaf spring.

FIG. 3 is a cross-sectional view of the circular leaf spring.

FIG. 4 is a partial plan view of a conventional circular leaf spring.

FIG. 5 is a sectional view of an essential part of the circular leaf spring.

FIG. 6 is a cross-sectional view of the circular leaf spring.

FIG. 7 is a cross-sectional view of the spring-charged magnetically shielded print head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coil 2 Yoke 3 Magnet 4 Printing wire 5 Amateur 6 Circular leaf spring 7 Front plate 8 Amateur holder 9 Nugget a Standing part b Non-standing part

Continuation of the front page (56) References JP-A-58-94475 (JP, A) JP-A-59-19174 (JP, A) JP-A-58-173808 (JP, A) Real opening 60-120846 (JP, A) , U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) B41J 2/275-2/28 B41J 2/235

Claims (1)

(57) [Claims] 1. A printing wire driving unit formed by welding a plurality of armatures holding a printing wire near a center of a circular leaf spring and fixing the printing wire driving unit to the circle. In a spring-charged magnetically shielded print head provided with an electromagnetic drive unit consisting of a magnet, a yoke, and a coil that deflects and adsorbs and releases a shaped leaf spring, the circular leaf spring is opposite to the side on which the amateur is fixed. By the side
And the vicinity of the portion to be welded and the circular plate
Continuously to the portion to flex rooted to form a standing part, said circular
When that Sessu dissolve the Oite the armature to the non-standing part of the leaf spring
In both cases, the height of the nugget generated by the welding
A print head characterized by being lower than an upright portion .