JPH03288660A - impact dot head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to a printhead for an impact printer.

[Prior Art] As this type of impact dot head, there is one shown in FIG. 8, for example. In the figure, 601 is an armature, and a fulcrum shaft 602 is rotatably held. electromagnet 6
When the suction part 604 is sucked by 03, the amateur 60
1 rotates and causes the printing wire 605 to protrude. electromagnet 6
03, the armature 601 returns to the standby position by the spring force of the coil spring 606. A cap member 608 molded from a wear-resistant material is attached to the engagement portion 607 of the coil spring 606 with the armature 601 to prevent the coil spring 606 and the armature 601 from being worn out.

However, in such a conventional structure, the mass of the cap member increases the moment of inertia of the drive system, which becomes an obstacle to increasing the speed. Furthermore, when used for a long period of time, the cap member wears out and the spring force changes, which may impair print quality or destroy the drive unit.

[Problems to be Solved by the Invention] The present invention has been made to solve these conventional problems, and its purpose is to provide a high-performance impact dot head that can provide high-speed and good printing quality over a long period of time. shall be.

[Means for Solving the Problems] Therefore, the impact dot head of the present invention includes a plurality of printing wires, an armature for driving the printing wires, an electromagnet for energizing and attracting or demagnetizing and releasing the armatures, and a standby position for the armatures. In an impact dot head, the impact dot head has a coil spring biased in a direction or a printing wire protrusion direction, and a cap member attached to an engaging portion between the coil spring and the armature, and a cavity is formed in at least one of the upper surface and the lower surface of the cap member. It is characterized by having a part or a hole formed therein.

The cap member is also characterized in that a cavity is formed on the upper surface of the cap member, and the cavity is filled with lubricating oil. Further, the cap member is characterized in that a hole is formed passing through the cap member from the upper surface to the lower surface, and the inside of the coil spring is filled with lubricating oil.

[Example] Hereinafter, the present invention will be explained in detail based on an example.

FIG. 1 shows a coil spring unit 10 which is a characteristic part of the present invention.
1 is a schematic diagram showing the configuration of FIG. The cap member 102, which is molded from a wear-resistant material such as nylon, polyacecool, or ceramics, has a flange portion 103 on the outer periphery of the upper surface, and a cylindrical shape on the lower surface with an outer diameter that is approximately the same as the inner diameter of the coil spring 104. It is inserted into one end of the spring 104. The coil spring 104 is telescopically housed in a coil spring holding member 108 that has a required number of cylindrical holes 105 and a slit 107 that serves as a swing space for the armature 106 . On the top surface of the cap member 102,
An armature 106 having a printing wire 109 at one end and a fulcrum shaft 110 at the other end is mounted. As shown in the sectional view of FIG. 2, a cylindrical cavity 111 is formed in the lower surface of the cap member 102, thereby greatly reducing the mass.

FIG. 3 shows a case where a coil spring unit 101 is used.
FIG. 3 is a diagram showing an embodiment of a stacked impact dot head. The wire drive units 112 and 113 are stacked in two stages, front and rear. The latter coil spring unit 101 includes the coil spring holding member 108 and the coil spring 10 as described above.
4, and a cap member 102, the front stage is a cylindrical part 1 protruding from the rear surface of the wire guide holder 114.
15 serves as a coil spring holding member. The wire guide holder 114 is inserted into the nose 117 while holding a plurality of wire guides 116. A core block 120 is attached to the rear surface of the nose 117 and includes a plurality of electromagnetic coils 119 positioned on a cylindrical portion 115 formed on the wire guide holder 114 and a dowel 118, and further includes a bobbin 12 of the electromagnetic coil 119.
Two side yokes 123 are positioned in the armature guide portion 122 formed in 1 and formed into a dish shape and a disk shape.
, 124 are placed.

Radial sulin l-(
(not shown) is provided to form a swinging space for the armature 106. A fulcrum shaft 110 attached to one end of the armature 106 is held between a dish-shaped side yoke 123 and a fulcrum support member 125.

The wire drive unit 112 configured in this manner is disposed further downstream (113), and the entire structure is fixed by a fixing spring 126.

FIG. 4 is a diagram showing another embodiment, in which a dish-shaped cap member 20
1 is attached so as to cover one end of the coil spring 202, improving ease of assembly. In this case, in order to prevent buckling of the coil spring 202, it is better to make only the upper part of the cylindrical hole 204 of the coil spring holding member 2030 larger in diameter to match the outer shape of the cap member, and make the lower part smaller in diameter than the upper part to match the outer shape of the coil spring. desirable.

FIG. 5 is a diagram showing still another embodiment, in which the cap member 3
A cylindrical cavity 302 is formed on the upper surface of 01,
The cavity is filled with high viscosity lubricating oil 303 such as grease. Therefore, although the area of engagement with the armature becomes slightly smaller, the upper surface of the cap member 301 is effectively lubricated by the lubricating oil 303 over a long period of time, and wear can be reduced.

FIG. 6 is a diagram showing still another embodiment, in which the cap member 4
A cylindrical hole 402 is formed in the center of 01, penetrating from the upper surface to the lower surface. The inside of the coil spring 403 is filled with lubricating oil 404 similar to the example shown in FIG.
At the time of compression of 3, the lubricating oil 404 is exposed on the upper surface of the character 402 for more effective lubrication.

FIG. 7 is a diagram showing still another embodiment, in which a cylindrical cavity 502 is formed in the center of the lower surface of a cap member 501 as in the embodiment of FIG. 2, and a small diameter hole penetrating the upper surface. 503 are formed in large numbers.

In this case as well, if the inside of the coil spring 504 is filled with lubricating oil 505, a small amount of lubricating oil 505 will always ooze out onto the top surface of the cap member 501 as the coil spring 504 expands and contracts, resulting in a good lubrication effect for a very long time. can get.

The shape of the cap member in the embodiments described above can be formed of metal by metal injection, lost wax method, forging, etc., and the present invention does not limit the material of the cap member.

[Effects of the Invention] As described above, according to the present invention, since the cap member has a structure in which a hollow portion is provided on the upper or lower surface, it is possible to significantly reduce the moment of inertia of the drive unit by reducing the mass of the cap member. As a result, it became possible to improve response performance. Furthermore, by filling the cavity with lubricating oil, an appropriate amount of lubricating oil can be effectively supplied for a long period of time, resulting in a significant improvement in durability.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the characteristic parts of an embodiment of the present invention, Fig. 2 is a sectional view showing the main parts of the invention, Fig. 3 is a side sectional view showing the embodiment of the invention, and Fig. 4. 7 to 7 are sectional views showing main parts of other embodiments of the present invention, and FIG. 8 is a schematic view showing an example of the prior art. 01 02 04 06 08 09 10 14 16 17 19 23 24 25 26 Coil spring unit cap member Coil spring armature Coil spring holding member Print wire fulcrum shaft Wire guide holder Wire guide nose Electromagnetic coil Dish-shaped side yoke Disc-shaped side yoke fulcrum shaft Support member fixed spring or more

Claims (3)

[Claims] (1) A plurality of printing wires, an armature that drives the printing wire, an electromagnet that magnetizes or demagnetizes the armature, a coil spring that urges the armature toward a standby position or a direction in which the printing wire projects; An impact dot head comprising a coil spring and a cap member attached to an engaging portion of the armature, characterized in that a cavity or a hole is formed in at least one of an upper surface or a lower surface of the cap member. (2) The impact dot head according to claim 1, wherein a cavity is formed in the upper surface of the cap member, and the cavity is filled with lubricating oil. (3) The impact dot head according to claim 1, wherein a hole is formed passing through the cap member from the upper surface to the lower surface, and the inside of the coil spring is filled with lubricating oil.