JPH0640133A - Friction gear of ribbon driver of printer - Google Patents

Abstract

PURPOSE:To make fitting operation easy and reduce the production cost, by a method wherein a friction rib which is formed integrally with two studs in contact with the inner circumference of a gear part, connects the two studs with each other and has a bent form is provided. CONSTITUTION:A friction gear of a driving device of a ribbon of a printer is constituted of a toruslike gear part 4 having a tooth profile on the outer circumference, two studs 1, 2 coming into contact with the inner circumference of the gear part 4 and a friction rib 3 which is formed integrally with those studs, connects them with each other and has bent form. Since the friction rib 3 is formed integrally with the studs 1, 2 separated into two from each other and in the bent form, the same can be bent easily. When the studs 1, 2 are fitted to the inner circumference of the gear part 4, since they are fitted under a state wherein the friction rib 3 is bent by a fixed quantity, fixed pressure is imparted to the gear part 4 by the studs 1, 2. The pressure becomes friction force at the time of turning of the gear part 4 and a fixed load is imparted at the time of running of the ink ribbon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction gear used in a ribbon drive device of a printer, which is used in the middle of a path for transmitting drive power to a ribbon and used for transmitting rotation under a constant load.

[0002]

2. Description of the Related Art In a ribbon drive device of a printer, a friction gear used in the middle of a path for transmitting drive power to the ribbon supplies power to a drive source in order to keep the running state of an ink ribbon constant. When transmitting,
It is necessary to transmit rotation with a constant load.

FIG. 5 is a plan view showing details of a stud as an example of a friction gear of a ribbon drive device of such a conventional printer.

As shown in FIG. 5, a conventional friction gear has an annular gear portion (not shown: having a tooth profile on its outer periphery).
1 and 3) and two studs 21 and 22 that come into contact with the inner circumference of the gear portion.
In order to apply a predetermined frictional force to the gear portions by pressing 1 and 22 against the gear portion, a spring 25 is mounted inside the studs 21 and 22, and the elastic force of the spring 25 causes the studs 21 and 22 to gear. It is configured to press against the part.

[0005]

As described above, since the friction gear of the ribbon drive device of the conventional printer is configured to press the stud against the gear portion by the spring, it takes time to install the spring. It has the drawback of being such.

[0006]

A friction gear of a ribbon driving device of a printer according to the present invention comprises an annular gear portion having a tooth profile on its outer circumference, two studs in contact with the inner circumference of the gear portion, and It is provided with two studs and a friction rib having a bent shape or a linear shape which is integrally formed and connects the two studs.

[0007]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a plan view showing a first embodiment of the present invention, and FIG. 2 is a view showing details of the stud of the embodiment shown in FIG.
(A) is a plan view and (b) is a perspective view.

In the embodiment shown in FIGS. 1 and 2, an annular gear portion 4 having a tooth profile on the outer periphery, two studs 1 and 2 in contact with the inner periphery of the gear portion 4, and two studs are provided. The friction ribs 3 are formed integrally with 1 and 2 and have a bent shape to connect them.

As shown in FIG. 2 (b), the studs 1 and 2 are separated from each other at the upper part that comes into contact with the inner circumference of the gear part 4, but are integrated at the lower part. The friction rib 3 is
Since it is formed integrally with the studs 1 and 2 which are separated into two pieces and has a bent shape, the studs 1 and 2 can be easily bent.

When the studs 1 and 2 thus constructed are mounted on the inner circumference of the gear portion 4, the friction ribs 3 are mounted in a state of being bent by a certain amount, so that the studs 1 and 2 are mounted on the gear portion 4. A constant pressure is applied to it. This pressure acts as a frictional force when the gear portion 4 rotates, so that a constant load is applied to the running of the ink ribbon, and the running state of the ink ribbon can be always maintained at a constant state.

The thickness of the friction rib 3 and the height and length of the friction ribs 3 are appropriately set according to the magnitude of the pressure applied to the gear portion 4 of the studs 1 and 2, that is, the magnitude of the frictional force when the gear portion 4 rotates. As a result, the desired value can be obtained. Therefore, this is set to an appropriate value according to the design standard of the ribbon drive device used.

With this structure, the friction rib 3 has the same function as a conventional spring.
Since a spring is unnecessary and the friction rib 3 and the studs 1 and 2 are integrally formed, the work of mounting the studs 1 and 2 on the gear portion 4 becomes extremely easy.

FIG. 3 is a plan view showing a second embodiment of the present invention, and FIG. 4 is a view showing the details of the stud of the embodiment of FIG.
(A) is a plan view and (b) is a perspective view.

In the embodiment shown in FIGS. 3 and 4, the friction rib 13 connecting the studs 11 and 12 has a linear shape. That is, the friction rib 13 linearly connects one end of the stud 11 and the end of the stud 12 facing it, but the action and effect thereof are the same as those of the embodiment of FIGS. 1 and 2. Exactly the same.

[0016]

As described above, in the friction gear of the ribbon driving device of the printer of the present invention, two studs that come into contact with the inner circumference of the gear portion are connected by friction ribs formed integrally with them. By constructing the stud to be attached to the gear part by bending the friction rib by a certain amount, it is possible to bring the stud into contact with the gear part at a constant pressure without using a spring. Therefore, the mounting work is facilitated, and the spring is not required, so that the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a plan view showing a first embodiment of the present invention.

2 is a diagram showing details of the stud of the embodiment of FIG.
(A) is a plan view and (b) is a perspective view.

FIG. 3 is a plan view showing a second embodiment of the present invention.

FIG. 4 is a diagram showing details of the stud of the embodiment of FIG.
(A) is a plan view and (b) is a perspective view.

FIG. 5 is a plan view showing details of a stud as an example of a friction gear of a ribbon drive device of a conventional printer.

[Explanation of symbols]

 1 ・ 21 ・ 21 Stud 2 ・ 12 ・ 22 Stud 3 ・ 13 Friction rib 4 ・ 14 Gear part 25 Spring

Claims (2)

[Claims] 1. An annular gear portion having a tooth profile on the outer periphery,
Two studs that come into contact with the inner circumference of the gear part;
A friction gear of a ribbon driving device for a printer, comprising: a plurality of studs; and a friction rib having a bent shape that is integrally formed and connects the two studs. 2. An annular gear portion having a tooth profile on the outer periphery,
Two studs that come into contact with the inner circumference of the gear part;
A friction gear for a ribbon driving device of a printer, comprising: a plurality of studs; and a linear friction rib that is integrally formed to connect the two studs.