JPH06286165A - Printing head - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent the print quality from deteriorating during long-term use. [Structure] The fulcrum shaft 19 is formed of a material of a system different from that of the lever 18. [Effect] Since the fulcrum shaft 19 is made of ceramic, adhesive wear with the lever 18 made of pure iron does not occur. Therefore, the print quality does not deteriorate even after long-term use.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print head for an impact dot matrix printer.

[0002]

2. Description of the Related Art As a conventional print head, for example, one described in Japanese Patent Laid-Open No. 62-101458 is known. The technique disclosed there is shown in FIGS.
Will be explained. Fix the printing wire 110 at the tip,
A plurality of radially arranged levers 118 are rotatably supported by a fulcrum shaft 119 made of hardened steel. The fulcrum shaft 119 is positioned by a slit provided in a positioning plate 113, and is further typified by hardened steel. A wear resistant sheet 112 made of a material sandwiches a yoke 111 made of pure iron, which is a magnetic material having a low mechanical strength, and a holder 115 made of brass, to prevent wear. The lever 118 is made of pure iron, which is a magnetic material, and is carburized to prevent wear.

[0003]

However, in the conventional print head, since the lever 118 and the fulcrum shaft 119 are made of the same type of metal material containing iron as a main component, adhesion wear is likely to occur, and the printing operation is repeated. The lever 118 and the fulcrum shaft 119 were worn out. As a result, the lever 118
However, there is a problem in that the printing operation behavior becomes unstable, the printing quality deteriorates, and further printing becomes impossible.

Therefore, the present invention has been made in order to solve the above problems, and an object thereof is to obtain a print head which eliminates the adhesive wear of the lever and the fulcrum shaft and does not deteriorate the print quality even in long-term use. To do.

[0005]

In order to solve the above-mentioned problems, the print head of the present invention has a lever rotatably supported by a plurality of fulcrum shafts arranged on the same plane, driven by an electromagnet to move the lever to the tip of the lever. In a print head for forming dots by hitting a fixed print wire on a print medium, the fulcrum shaft is formed of a material of a system different from that of the lever.

The fulcrum shaft is formed of ceramic.

The fulcrum shaft is made of resin.

[0008]

[Function] Since the lever and the fulcrum shaft are made of different materials, adhesion wear does not occur and the lever and the fulcrum shaft are less likely to wear.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is a front view of an embodiment of the print head of the present invention, and FIG. 1B is a side view. FIG. 2 shows A in FIG.
It is a fragmentary sectional view showing the -A section.

A print head 1 of an embodiment based on FIGS. 1 and 2.
The configuration and operation of will be described. In this embodiment, 24 fulcrum shafts 19 are arranged on the same plane at equally divided positions on the circumference, and a lever 18 is rotatably supported by each fulcrum shaft 19, and the printing wire 10 is attached to the tip of the lever 18. Have. Since the configuration and operation for driving each print wire 10 are the same, only one unit will be described.

A solenoid coil 4 having a winding wound around a coil bobbin 3 is inserted into a core 2 integrally formed and arranged on the same plane of a core block 8 made of a magnetic material having high magnetic permeability, and an electromagnet 5 is inserted. Is formed. The terminal of the solenoid coil 4 is soldered to the substrate 6 and connected to a driver circuit (not shown) through the connector 7. A yoke 11, a wear resistant sheet 12, a positioning plate 13, and a holder 15 are laminated on the core block 8 and fixed by a leaf spring 16. Core block 8
The outer periphery of the heat radiation member 17 is covered. Solenoid coil 4 and core block 8, and core block 8 and heat dissipation member 1
A resin having a high thermal conductivity is filled between 7 and 7. The lever 18 made of pure iron is a fulcrum shaft 19 made of ceramic.
Rotatably supported by. The basic structure is the same as that of the conventional print head described with reference to FIGS. 3 and 4, except that the fulcrum shaft is made of ceramic.

In the standby state, the lever 18 is pushed by the return spring 21 held by the spring holding member 20 and is pressed against the damper 22. The printing wire 10 is the lever 1
It is fixed to the tip of 8 and is held by a plurality of wire guides 24 so as to be slidable in the axial direction.

When the solenoid coil 4 is energized by a driver circuit (not shown), the lever 1 is moved by the electromagnet 5.
8 is attracted to the core 2 and rotates about the fulcrum shaft 19. Therefore, the print wire 10 fixed to the tip of the lever 18 flies rightward in FIG.
The print medium 29 held by the platen 27 is struck via 8 to print. After printing, lever 18 returns spring 2
It is pressed by 1 and returns to the standby position.

During this printing operation, the lever 18 and the fulcrum shaft 19
Rub against each other, but because the material system of the lever 18 and the fulcrum shaft 19 are different, adhesion wear does not occur, and the lever 18 and the fulcrum shaft 19
Wear is unlikely to occur.

In this embodiment, the material of the fulcrum shaft 19 is ceramic, but it can be made of resin, for example, and by using resin having a small friction coefficient for the material of the lever, wear resistance and Slidability can also be improved.

[0016]

As described above, according to the present invention, since the fulcrum shaft is made of a material different from that of the lever, abrasion of the fulcrum shaft and the lever is unlikely to occur, and the behavior of the lever is stable even in long-term use. It is possible to eliminate deterioration of print quality.

[Brief description of drawings]

FIG. 1A is a front view and FIG. 1B is a side view of an embodiment of a print head of the present invention.

FIG. 2 is a partial cross-sectional view of the AA surface shown in FIG. 1A of the embodiment of the print head of the present invention.

FIG. 3 is a cross-sectional view showing a conventional technique.

FIG. 4 is an exploded perspective view of a conventional technique.

[Explanation of symbols]

 1 Printing Head 5 Electromagnet 10 Printing Wire 12 Wear-Resistant Sheet 13 Positioning Plate 18 Lever 19 Support Shaft

Claims (3)

[Claims] 1. A dot is formed by driving a lever, which is rotatably supported by a fulcrum shaft arranged on the same plane, by an electromagnet to drive a print wire fixed to the tip of the lever to a print medium. In the print head described above, the fulcrum shaft is formed of a material of a different system from the lever. 2. The print head according to claim 1, wherein the fulcrum shaft is made of ceramic. 3. The print head according to claim 1, wherein the fulcrum shaft is made of resin.