JPS5928188B2 - type head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a type head whose frame portion and finger portion are integrally formed of thin metal plates, and which has low inertia and does not reduce printing speed.

FIG. 1 shows a top view of a conventional type head used in a motor-controlled impact printer.

Its structure consists of a disc-shaped frame part 1 having a circular hole P in the center for coupling to the shaft of a selection motor that selects type; a finger part 2 consisting of a plurality of fingers provided corresponding to each type; and a type section 3. During printing, the flexibility of the fingers and frame allows the displacement of the type part. The characteristics required of the type head are to reduce the moment of rotational inertia in order to increase the printing speed, and to quickly return the type part to the initial position after printing is completed.
In other words, it is possible to increase the natural frequency of the type head. For the purpose of lowering the inertia, an extremely effective means is to reduce the thickness of the frame portion and the finger portion.

However, in the case of a conventional flat plate configuration, the natural frequency also decreases at the same time as the wall thickness is reduced. Therefore, there was a drawback that lowering the inertia did not necessarily lead to an increase in printing speed. When using high-quality, long-life metal matrix type and integrally molding the fingers and frame with the same material as the type, the specific gravity will be higher than when integrally molded with plastic. Therefore, reducing the wall thickness is an extremely important issue, but it has been difficult to achieve this due to the drawbacks mentioned above. In order to eliminate the drawbacks of the conventional type head, the present invention consists of a single thin metal plate with a thickness of 0.1 mm, and ribs are integrally formed only on the frame portion of the type head. It can be made inertial and rigid, and the natural frequency can be increased.

The present invention will be explained based on the drawings. FIG. 2 shows a top view of the type head of the invention.

In the figure, the same symbols as in FIG. 1 indicate the same parts. Reference numeral 4 denotes a rib provided on the frame part 1 on the circumference of the base of the attachment part of the finger part 2 to the frame part 1.

FIG. 3a shows a sectional view taken along the line AA in FIG. 2. 4-1
is the apex line of the rib 4, and the rib 4 has a triangular cross section.

Reference numeral 5 denotes a rib provided radially with respect to the motor mounting hole PilC, and the cross-sectional shape is the same as that of the rib 4.

It can also be formed into a U-shape as indicated by the apex line 4'-1 of the rib 11 in FIG. 3b. The conventional example shown in Figure 1 has a thickness of 0.5wr.
m plastic type head, diameter 90Tf
r1f11 finger part 10wm, frame part 70m
It had a natural frequency of 90Hz.

The type part is also integrally formed, but the type part made of plastic is easily damaged (it has a short lifespan). 0.1 as corresponding to the conventional type head? A metal plate with spring properties made of the same dimensions as a conventional plastic plate has a moment of inertia of 30 fri and a fixed frequency of 20 to 30 Hz.

Under these conditions, it cannot be used as a type head. In the present invention, only the frame portion is provided with integrally formed protruding ribs.

Based on the above structure, the rigidity of the frame portion is increased compared to the conventional one, and it is possible to prevent a decrease in the natural frequency due to thinning of the wall, and thus a decrease in printing speed. Since the ribs are made of a metal material, the ribs can be easily formed by press molding. Third
The figure shows the cross-sectional shape of the rib perpendicular to the longitudinal direction.
In this case, it is V-shaped, but the effect of high rigidity,
Depending on the workability of the material, it can be made into several different shapes, such as a U-shape or a V-shape.

For the same reason, the number of ribs may be, for example, only the circular rib 4 shown in Fig. 2, radial ribs 5, 5, etc. They may be provided at circular intervals, or they may be provided circularly and radially at the same time as shown in FIG. FIG. 4 shows another embodiment of the invention.

In order to further reduce the inertia of the frame part, the frame part was punched out using a plastic V-strip, and the frame part was made up of a ring part 6, spoke parts 7, 7, etc., and a hub part 8. It has ribs on the ring and on the individual spokes. A part of the frame is punched out using a press or the like to form a ring shape, which lowers the inertia, but reduces the natural frequency.

Therefore, by providing ribs on the annular ring portion and spoke portions, the desired natural frequency of the type head can be obtained.
That is, when lowering the inertia by providing a punched portion using a press V or the like as shown in FIG. 4, the embodiment of the present invention can be expected to have even greater effects. The ribs can be provided separately on the ring part and the spoke part to form separate type heads. As can be understood from the above description, the present invention is to form ribs on the frame portion of the type head to increase its rigidity.

Therefore, the shape of the frame portion and the number of ribs can be appropriately selected. The type head of the present invention can reduce the wall thickness and have low inertia, and the frame can be provided with ribs to increase rigidity, so the natural frequency that conventionally occurs due to low inertia can be reduced. We use especially high-quality, long-life type that can prevent printing speed from slowing down.
For type heads where the finger and frame parts are integrally formed from the same material, thinning can be achieved without reducing printing speed, making it possible to achieve both high quality printing and low inertia of the type head. , etc.

[Brief explanation of drawings]

FIG. 1 is a plan view of a conventional type head, FIG. 2 is a plan view of the present invention, and FIG.
Figure b shows a sectional view of the U-shape, and Figure 4 shows another embodiment of the invention. H: Type head, 1: Frame part, 2: Finger part,
3: Type part, P: Mounting hole to motor shaft, K: Type head, 4: Circular rib, 4-1: Circular rib top line, 5: Radial rib, 5-1: Radial rib top line, L; type head,
6: ring part, 7 spoke part, 8: bu part, 9: hole.

Claims (1)

[Scope of Claims] 1. A disk-shaped frame portion having a hole directly connected to a selection motor at the center, a finger portion having a plurality of fingers extending radially from the frame portion, and motherboard type provided at the tips of the fingers. In the disc-shaped type head, the disc-shaped type head is constructed of a metal body other than the type part with a thickness of at most 0.1 mm, and a rib that provides rigidity is provided integrally and protruding only in the frame part. A type head characterized by: 2. The type head according to claim 1, wherein each of the ribs has at least one circular shape. 3. The type head according to claim 1, wherein the ribs are arranged radially. 4. The type head according to claim 1, wherein the ribs are circular and radial.