JPS5987179A - Printing head - Google Patents

Abstract

PURPOSE:To stabilize the characteristic properties of a printing head by a method in which a supporting point is formed of a support rubber integrated with a support plate to be pressed on an armature in a wire dot printer and the stroke is regulated by a stopper rubber. CONSTITUTION:A stopper plate 7 integrated with a support rubber 5 and a stopper rubber 6 is pressed on an armature 2 and the outside end face of a core frame 4 at the support rubber 5 as a supporting point by a rear cover 11 and a cover spring 9, and the stroke of the armature 2 is regulated by the stopper rubber 6. To obtain a proper stroke, only the step difference dimensions between the support rubber 5 and the stopper rubber 6 is controlled. Since there is no specific fitting reference face, variations in the stroke due to thermal expansion do not occur. Even when abrasion takes place in the core frame 4, etc., the stroke is not varied and therefore, a printing head having stable characteristic property can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a print head for a dot matrix printer that prints by selectively impacting a recording medium with a print wire.

In a conventional print head, as illustrated in FIG. 1, an armature 2 holds a print wire 1 at one end;
The other end is supported by a support rubber 5 integrally molded with the stopper plate 7 on the end face of a cylindrical core frame 4 with one end closed. The armature 2, core frame 4, and core stud 3 form a magnetic circuit with a coil 10 wound around the core stud 3. When a current is applied to the coil 10 via a printed circuit board 16, the armature 2 is attracted to the end face of the coil 10
When the current to is cut off, the armature 2 is moved away from the end face of the core stud 3 by the return spring 8, hits the stopper rubber 6, and is stopped at that position. printed wire 1
is guided by an intermediate guide 15 held by the head frame 13 according to the movement of the armature 2, and is guided by the main guide 14 to the platen 1 via an ink ribbon and paper (not shown).
7 and prints.

In such a print head, the stopper plate door is fixed to the rear end surface 13a of the hand frame 13 with screws. In such a system, the rear end surface of the head frame 13 and the positions of the core frame 4 and core start 3 require high dimensional accuracy in order to obtain uniform and appropriate strokes for the plurality of armatures, and also require high dimensional accuracy due to thermal expansion, wear, etc. There were drawbacks such as large stroke changes due to dimensional changes resulting in unstable characteristics.

The purpose of the present invention is to achieve printing with stable characteristics and less variation in the strokes of multiple armatures.

The objective is to provide a

In the present invention, a stopper plate integrally formed with a support rubber and a stopper rubber forms a fulcrum of the armature by pressing the armature with the support rubber part by spring force, and a "C stroke" is defined in the stopper rubber part. Features.

Since the stopper plate is always pressed in the direction of the core surface by the spring force, an appropriate stroke can be obtained by controlling only the step size between the support rubber and the stopper rubber, and the stopper plate has a specific fixed reference surface. Therefore, it is possible to always maintain a constant stroke even when dimensional changes due to thermal expansion and friction of the core frame, core stud, etc. occur.

FIG. 2 shows an embodiment of the present invention. Note that the same parts as in FIG. 1 are indicated by the same reference numerals.

A stopper plate 7, in which a support rubber 5 and a stopper rubber 6 are integrally molded, is pressed by the support rubber 5 against the outer end surfaces of the armature 2 and the core frame 4 by the rear cover 11° cover spring 9, and forms a fulcrum of the armature 2. A stopper rubber 6 defines the stroke of the armature 2.

By adopting the above configuration, in order to obtain a proper armature stroke, it is only necessary to manage the step dimension between the support rubber 5 and the stopper rubber 6, and the stopper plate 7 also has a specific mounting reference surface. Therefore, there is no stroke change due to thermal expansion changes in the mounting reference surface position, which was seen in conventional methods. Furthermore, as mentioned above, since the armature 2 is always pressed against the outer end surface of the core frame 4,
Core frame 4. Core stud 3. and armature 2
Even with dimensional changes due to wear, there is no fraying of the armature fulcrum or changes in stroke, etc., which were observed in conventional systems.

Therefore, by adopting the configuration of the present invention, a print head with stable characteristics without stroke change can be provided.

[Brief explanation of drawings]

FIG. 1 is a drawing showing the structure of a conventional print head, and FIG. 2 is a drawing showing the structure of an embodiment of the present invention. ■...Printed wire, 2...Armature, 3...Core start, 4...
Core frame, 5...Support rubber, 6...
...stopper rubber, 7..1..stopper plate, 8.
...Return spring, 9...Cover spring, 10...Coil, 11...Pa°°
Rear cover, 12...Front cover, 13.
・Pa°° head frame, 14... Main guide,
15... Intermediate guide, 16... Printed circuit board.

Claims (1)

[Claims] An electromagnetic magnet is composed of a core stud with a coil wound thereon, a core frame, and an armature supported at the outer end of the core frame, and is used to support the armature in a print head that prints using a wire held at the tip of the armature. The rubber member and the rubber part acting as a stopper are integrally molded on the same plate-shaped member, and the plate-shaped member is held down by the rubber part to the armature and the outer end of the core frame by a spring force. print head.