JPH0357679A - Ribbon feed mechanism for printer - 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] [Summary] This invention relates to a ribbon feeding mechanism used in printers, which is equipped with a simple torque limiter mechanism, and which utilizes the power of the drive shaft of the printer head. In a printer's ribbon feeding mechanism that feeds the ribbon, if a torque exceeding a predetermined value is applied to the rotating shaft, the bevel gear will idle against the one-way bearing attached to the rotating shaft, preventing the ribbon from breaking. The purpose of the present invention is to provide a ribbon feeding mechanism for printers equipped with a torque ripple mechanism with a simple configuration. A one-way bearing attached to the shaft, two bevel gears attached to the one-way bearing that follow only one direction of the rotating shaft and idle when rotating in the opposite direction, and a bevel gear that meshes with the bevel gear. In the ribbon feeding mechanism for printers, the one-way bearing has a cutout on its outer periphery, and when a torque of more than a predetermined value is applied to the rotating shaft, the one-way bearing rotates. A feature is that the bevel gear is elastically fitted into a one-way bearing so that the shaft rotates idly.

[Industrial application field]

The present invention relates to a ribbon feeding mechanism used in a printer, and more particularly, to a ribbon feeding mechanism for a printer that is provided with a simple torque gripping mechanism.

[Conventional technology]

Conventionally, in the ribbon feeding mechanism of a printer, as shown in FIG. 5, a rotary shaft 1.2 that rotates in synchronization with a drive shaft of a printer head (not shown) is supported by a support member 3, and a lower rotary shaft 1.2 is supported by a support member 3. A bevel gear 4.5 with a built-in one-way bearing is attached to the rotating shaft 2.
It has the property of only following rotation in one direction and idling when rotating in the opposite direction, and the idling directions are set to be opposite to each other.

Further, the bevel gears 4 and 5 mesh with a bevel gear 6, and a ribbon drive shaft 7 to which the bevel gear 6 is attached rotates in one direction to feed the ribbon.

Therefore, the rotation of the drive shaft of the printer head is first transmitted to the rotary shaft 1 through the tie pulley 8, and the rotary shaft 2 rotates in forward and reverse directions through the drive gear 9 and the driven gear 10.

The forward and reverse rotation of this rotating shaft 2 is controlled by bevel gears 4, 5.6.
This is converted into rotation of the ribbon drive shaft 7 in only one direction by the differential gear mechanism, and the ribbon is fed in one direction.

[Problems to be solved by the invention] In the conventional printer ribbon feeding mechanism,
When an abnormal load is applied to the drive side, the ribbon is forcibly fed out, causing a problem such as breakage of the ribbon.

As a countermeasure against this, a friction plate 11 is inserted between the rotating shaft l and the tying pulley 8, and a clutch mechanism is used as the torque limiter mechanism.

However, as a recent trend, even printers are required to be small, lightweight, and inexpensive.
Conventional torque limiter mechanisms are complicated and expensive.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a ribbon feeding mechanism for a printer that uses the power of the drive shaft of the printer head to feed the ribbon. When a torque exceeding a predetermined value is applied, the bevel gear idles against the one-way bearing attached to the rotating shaft, preventing the ribbon from breaking.This is a simple torque limiter. An object of the present invention is to provide a ribbon feeding mechanism for a printer equipped with a mechanism.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a rotating shaft 21 that rotates forward and backward in synchronization with the drive shaft of a printer head, a one-way bearing 22 that is attached to this rotating shaft 21, and a rotating shaft that is attached to the one-way bearing 22 and rotates. axis 2
1, two bevel gears 23 and 24 follow only one direction and rotate idly against rotation in the opposite direction, and the bevel gear 23
．． 24, and a ribbon drive shaft 26 for feeding the ribbon. A feature is that the bevel gears 23 and 24 are elastically fitted into the one-way bearing 22 so that the rotating shaft 21 idles when a torque of a predetermined value or more is applied.

[Effect]

As is clear from the above structure, a notch is formed on the outer periphery of the one-way bearing, and the bevel gear is elastically fitted to this one-way bearing, so that a torque of more than a predetermined value is applied to the rotating shaft. At this time, the bevel gear idles relative to the rotating shaft, and the ribbon drive shaft also stops.

(Embodiments) Hereinafter, embodiments of the printer ribbon feeding mechanism according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of a ribbon feeding mechanism for a printer showing a first embodiment of the present invention, FIG. 2 is a cross-sectional view showing a bevel gear and one-way bearing used in the ribbon feeding mechanism for a printer, and FIG. ．． FIG. 4 shows a second embodiment of the present invention, and is a front view and a side view showing the configuration of a bevel gear.

In FIG. 1, the printer ribbon feeding mechanism according to the present invention includes a rotating shaft 21 rotatably supported by a support member 20 having a substantially U-shaped cross section, a one-way bearing 22 attached to the rotating shaft 21, and a one-way bearing. Two bevel gears 23 and 24 equipped with a torque limiter mechanism are attached to 22, and a bevel gear 25 that meshes with these bevel gears 23 and 24 is attached, and is supported by the support member 20 so as to be rotatable in only one direction. It consists of a ribbon drive shaft 26.

At the back, the rotating shaft 21 is connected to the drive shaft of the printer head via a gear 27, and a one-way bearing 2
The bevel gears 23 and 24 attached to the shaft 2 follow the rotation of the rotating shaft 21 in only one direction, and have the function of idling when the rotation is in the opposite direction. With this setting, forward and reverse rotation of the rotating shaft 21 is converted into unidirectional rotation of the ribbon drive shaft 26.

By the way, the feature of the present invention is to provide a simple and inexpensive torque grip mechanism, and in this example, the second
As shown in the figure, a notch 28 is formed on the outer periphery of the one-way bearing 22, and a bevel gear 23.
4 is a resin gear, which has a slit 29 inside, and when a torque of a predetermined value or more is applied to the rotating shaft 21, the bevel gear 23 is connected to the one-way bearing 22.
．． 24 will be idling. Therefore, the ribbon drive shaft 2 that feeds out the ribbon stored in the ribbon cassette 30
6 will stop and the ribbon will not break.

In this way, in this example, one-way bearing 2
There is an advantage that the torque limiter mechanism can be obtained by a simple and inexpensive construction of devising the shapes of the bevel gears 23 and 24.

Next, a second embodiment of the present invention will be described based on FIGS. 3 and 4.

In this example, as shown in the figure, the leaf spring 31 is attached to the bevel gear 23.
．． 24, one-way bearing 2
When a torque greater than the spring pressure of the temporary spring 31 that clamps the outer surface of the ribbon is applied to the rotating shaft 21, the bevel gears 23 and 24 are fixed, the rotating shaft 21 idles, and the ribbon drive shaft 26 stops. Therefore, the same effects as in the first embodiment can be obtained.

〔Effect of the invention〕

As is clear from the above description, in the ribbon feeding mechanism for printers according to the present invention, torque can be increased by adding innovation to the shapes of the one-way bearing and the bevel gear, or by adding a leaf spring to the simple and inexpensive structure. A limiter mechanism is obtained, which is smaller and lighter than conventional friction-slip clutch mechanisms, and has the effect of being expected to significantly reduce costs.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a ribbon feeding mechanism for a printer showing a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a bevel gear and one-way bearing used in the ribbon feeding mechanism for a printer. FIG. ．． FIG. 4 shows a second embodiment of the present invention, and FIG. 5 is a front view and a side view showing the structure of a bevel gear, and FIG. 5 is a sectional view showing the structure of a conventional printer ribbon feeding mechanism. In the figure, 20...Support member, 21...Rotating shaft, 22...One-way bearing, 23.24.25...Bevel gear, 26...Ribbon drive shaft, 28...Notch part , 29...slit, 31... plate spring.

Claims (1)

[Claims] A rotating shaft (21) that rotates forward and backward in synchronization with the drive shaft of the printer head, a one-way bearing (22) attached to this rotating shaft (21), and a one-way bearing (
22), two bevel gears (23, 24) that follow only one direction of the rotating shaft (21) and idle when rotating in the opposite direction, and the bevel gears (23, 24) In the ribbon feeding mechanism for printers, the one-way bearing (22) has a notch (2
8) is formed, and the bevel gears (23, 24) are fitted with one-way bearings (22) so that the rotating shaft (21) idles when a torque of a predetermined value or more is applied to the rotating shaft (21). A ribbon feeding mechanism for a printer, characterized in that it is elastically fitted into a ribbon feeding mechanism.