JPH0312540Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Application of the Invention) The present invention relates to an ink ribbon feeding mechanism of a printer.

(Background of the invention) A printer is generally used with an ink ribbon disposed between a platen and a printing head. The ink ribbon is stored in a ribbon cassette 10 as shown in FIG.
It is stored in. That is, the endless ink ribbon 11 is stretched around guide rollers 13, 14, 15 and a drive roller 16, which are rotatably provided in a case 12.
Portions 4 and 15 are exposed from the case 12.
Further, the case 12 is provided with a pressure roller 17 that presses against the drive roller 16 via the ink ribbon 11, and a guide plate 18 having a slit through which the ink ribbon 11 passes. The ribbon cassette 10 may be mounted on the printer body, or
Alternatively, the ink ribbon 11 is used by being mounted on a printing carrier to which a printing head is attached, and driving the driving roller 16 to feed the ink ribbon 11.

Conventional ink ribbon feeding mechanisms use a dedicated motor for ink ribbon feeding, convert the power of the print carrier movement using a belt, rope, or rack specifically designed for ink ribbon feeding, or combine planetary gears. A method is generally known in which the meshing of gears is changed when the direction of movement of the print carrier changes. However, since such a mechanism has a large number of parts and a complicated structure, it is expensive and prone to failure.

(Objective of the invention) An object of the invention is to provide an ink ribbon feeding mechanism for a printer that has a simple structure and can reliably feed the ink ribbon in the same direction regardless of the running direction of the print carrier.

(Embodiment of the invention) An embodiment of the invention will be described below with reference to FIGS. 2 and 3. A print carrier 21 to which a print head 20 is attached is slidably inserted into guide rods 22 and 23 fixed to the printer body. Further, the print carrier 21 is provided with guide rollers 24 to 27 on the front surface of the print head 20 for guiding the ink ribbon 11 of the ribbon cassette 10.

The ribbon cassette 10 is mounted on a ribbon cassette mounting table 31 provided on the upper plate 30a of the printer main body.
It is positioned and placed on top. An idler pulley shaft 32 is rotatably supported by the upper plate 30a and lower plate 30b below the drive roller 16 of the ribbon cassette 10 in the state where the ribbon cassette 10 is placed. The idler pulley shaft 32 has a collar portion 32a formed approximately at the center, and clutch portions 3 formed above and below the collar portion 32a.
2b, 32c and the clutch portions 32b, 32c.
Pulley shaft portions 32d formed on the upper and lower sides of the
32e and the drive roller 16 of the ribbon cassette 10.
The drive roller engaging portion 32f is formed by cutting both sides of the distal end portion of the pulley shaft portion 32d so as to engage with a groove formed at the lower end of the pulley shaft portion 32d. A clutch spring 3 is provided in each of the clutch parts 32b and 32c.
Idler pulleys 35 and 36 are rotatably fitted into the pulley shaft portions 32d and 32e, respectively. The clutch springs 33 and 34 have one end engaged with the side surface of the idler pulley 35 and 36, respectively, and the other end in a free state. And clutch spring 3
3, in FIG. 2, the idler pulley 35 is A ₁
When the idler pulley 35 rotates in the direction A2, it is tightened by the clutch part 32b, and when the idler pulley 35 rotates in the direction _A2 , it is wound so that it becomes looser than the clutch part 32b. Similarly, the clutch spring 34 also releases the clutch portion 32c when the idler pulley 36 rotates in the _A1 direction.
The clutch portion 32c is wound so as to loosen when the idler pulley 36 rotates in the _A2 direction. That is, the clutch portion 32b and the clutch spring 33 and the clutch portion 32c and the clutch spring 34 constitute a one-way rotating clutch.

The printer body has a print carrier drive motor 4.
A wire rope 42 for driving the print carrier is wound around a pulley 41 for driving the print carrier fixed to the output shaft of the motor 40. One end 42a of the wire rope 42 is fixed to one side of the print carrier 21 via an idler pulley 35. The other end 4 of the wire rope 42
2b passes through an idler pulley 36, and further passes through a direction conversion pulley 43 which is rotatably supported by support parts 30c and 30d of the printer main body, and then connects to the print carrier 21.
is fixed to the other side of the

Next, the effect will be explained. Motor 40 is the arrow
B When rotated in _one direction, the wire rope 42
The print carrier 21 is pulled in the _C1 direction, and is guided by the guide shafts 22 and 23 to move in the _D1 direction. At this time, the idler pulley 35 rotates in the direction of arrow _A1 , which causes the clutch spring 33 to rotate.
is tightened by the clutch portion 32d, and the idler pulley shaft 32 rotates in the same direction as the idler pulley 35 via the clutch spring 33, that is, in the direction of arrow _A1 .
On the other hand, since the idler pulley 36 rotates in the _two directions of arrow A, the clutch spring 34
The idler pulley 36 is further loosened, and the idler pulley 36 rotates freely on the idler pulley shaft 32. When the idler pulley shaft 32 rotates in the direction of arrow _A1 as described above, the drive roller 16 of the ribbon cassette 10 moves in the direction of the arrow A1.
The ink ribbon 11 is rotated in the _A1 direction and sent in the arrow E direction.

When the motor 40 reverses in the direction of arrow _B2 , the wire rope 42 is pulled in the direction of arrow _C2 , and the print carrier 21 moves in the direction of arrow _D2 . At this time,
Since the idler pulley 35 rotates in the _two directions of arrow A, the clutch spring 33 becomes looser than the clutch portion 32d, and the idler pulley 35 rotates in the direction of the idler pulley shaft 32.
Rotate freely on top. On the other hand, since the idler pulley 36 rotates in the direction of arrow _A1 , the clutch spring 34 is tightened to the clutch portion 32e, and the idler pulley shaft 32 is rotated by the clutch spring 34.
in the same direction as the idler pulley 36, i.e. in the direction of the arrow
A Rotates in _one direction. When the idler pulley shaft 32 rotates in the direction of the arrow _A1 in this manner, the drive roller 16 of the ribbon cassette 10 is rotated in the direction of the arrow _A1 , and the ink ribbon 11 is rotated in the same manner as in the previous case.
is sent in the direction of arrow E.

In this way, the print carrier 21 follows the arrows D ₁ , D ₂ ,
No matter which direction the ink ribbon 11 travels, the ink ribbon 11 is sent in the direction of arrow E.

(Effects of the invention) As is clear from the above explanation, according to the invention, the idler pulley shaft rotates in one direction no matter which direction the two idler pulleys to which the print carrier driving Wyra ropes are hung rotate. In this way, the idler pulley shaft and the two idler pulleys are respectively connected via clutch springs, and the drive roller of the ribbon cassette is driven by the rotation of the idler pulley shaft. , the ink ribbon can be reliably fed in the same direction regardless of the running of the print carrier. Furthermore, since it has a simple structure, it is possible to significantly reduce costs.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a ribbon cassette, Fig. 2 is a schematic plan view showing one embodiment of the present invention, and Fig. 3 is a sectional view of a ribbon cassette.
FIG. 2 is a schematic cross-sectional view on the right side of the figure. 10... Ribbon cassette, 16... Drive roller, 20... Print head, 21... Print carrier, 32... Idler pulley shaft, 32b, 32c
...Clutch part, 33, 34...Clutch spring,
35, 36... Idler pulley, 40... Print carrier drive motor, 41... Print carrier drive pulley, 42... Print carrier drive wire rope.

Claims (1)

[Scope of utility model registration request] The ribbon cassette is mounted on the printer body, and the print carrier drive wire rope is wound around the print carrier drive pulley driven by the print carrier drive motor, and both ends of this wire rope are rotatable around the idler pulley shaft. In a printer that is fixed to both sides of a print carrier by being stretched over two supported idler pulleys, the idler pulley shaft rotates in one direction regardless of which direction the idler pulley rotates. , the idler pulley shaft and the two idler pulleys are each coupled via a clutch spring, and the drive roller of the ribbon cassette is driven by rotation of the idler pulley shaft. An ink ribbon feeding mechanism for a printer characterized by: