JPS5837655Y2 - Ink ribbon reversal mechanism - Google Patents

Description

[Detailed description of the invention] The present invention uses an ink ribbon reversing mechanism of a printer, etc., in particular, a driving force is alternately linked to an ink ribbon spool gear by the revolution of a planetary gear, and the feeding direction of the ink ribbon is reversed. related to what was done.

For example, a structure as shown in Fig. 1 is known as a structure in which the ink ribbon feeding direction is reversed by switching the engagement with the ink ribbon spool gear by the revolution of the planetary gear as described above. , a conventional example thereof will be explained below.

In FIG. 1, 1 is an ink ribbon, 2 and 3 are spool shaft gears, 4 is a reversible motor, and 5 is a drive gear.

The drive gear 5 is fixed to the shaft 4a of the motor 4.

Reference numeral 6 denotes a planetary gear, which is rotatably supported by the swing lever 7 and always meshes with the drive gear 5.

The swing lever 7 is fitted onto the motor shaft 4a, and is pressed against the back surface of the drive gear 5 by a spring (not shown).

8 and 9 are detection levers, and 10 is a changeover switch. In the above-described configuration, when the motor 4 rotates to the left, the drive gear 5 also rotates to the left, and the planetary gear 6 rotates to the right.

At the same time, the swing lever 7 rotates to the left along with the rotation of the drive gear 5 due to the action of spring friction, causing the planetary gear 6 to revolve to the left.

Therefore, the planetary gear 6 meshes with the spool shaft gear 3, rotates the spool shaft gear 3 to the left, and sends the ink ribbon 1 in the direction of the arrow.

However, after that, when the remaining amount of the ink ribbon on the right side decreases, the switch 10 is actuated by counterclockwise rotation of the detection lever 8, and the motor 4 is rotated in the reverse direction.

The drive gear 5 rotates clockwise due to the reverse rotation of the motor 4.

Then, the swing lever 7 rotates to the right, and the planetary gear 6 rotates to the left while revolving to the right and meshes with the spool shaft gear 2.

The spool shaft gear 2 rotates clockwise to wind up the ink ribbon 1 in the opposite direction.

The conventional example in which the motor is reversed by the action of the detection lever and the planetary gear revolves has been described above, but with such a configuration, a means for reversing the motor in conjunction with the detection of the ink ribbon is particularly required. To be, the configuration,
In particular, the circuit becomes complicated, which is not desirable.

In view of the above-mentioned drawbacks, the present invention uses the unidirectional rotation of a drive source that constantly rotates back and forth regardless of the state of the ink ribbon to feed the ink ribbon, and only when the restriction by the detection lever is released. To provide an ink ribbon reversing mechanism in which the feeding direction of an ink ribbon is reversed by switching the meshing of a planetary gear with a spool shaft gear.

Hereinafter, the present invention will be explained based on the illustrated embodiments.

In FIG. 2, numeral 11 is an ink ribbon, which has a detection eyelet 11a near the end of the ink ribbon.

12.13 is a spool shaft gear. A drive gear 15 is constantly rotated back and forth by a drive source.

For example, the driving source may be a head transport mechanism of a serious printer.

Reference numeral 16 denotes a planetary gear, which is pivotally supported by a swing lever 17 and meshes with the drive gear 15.

The swing lever 17 forms a tip 17a, and is supported by a shaft 15a of the drive gear 15.

Reference numeral 18 and 19 designate a detection lever, which forms passage grooves 18 a and 19 a for the ink ribbon 11 and arm portions 18 b and 19 b, and is biased by a driving force for left rotation and right rotation, respectively, by a spring 20. However, the detection lever 18 is stopped by the stopper pin 21, and the detection lever 19 is stopped by the arm portion 19b coming into contact with the tip end 17a of the swinging lever 17.

A friction brake plate 23 forms a friction arc portion 23a, and is fixed such that the outer periphery of the planetary gear 16 is always in contact with the arc portion 23a.

Next, the operation of the above configuration will be explained.

In FIG. 2, the drive gear 15 is rotating to the left;
The planetary gear 16 rotates clockwise, and the spool shaft gear 13 rotates counterclockwise to wind up the ink ribbon 11 in the direction of the arrow.

In this state, the planetary gear 16 is rotating clockwise while its outer periphery is in contact with the arc portion 23a of the friction brake plate 23, so that it is about to revolve to the left due to the reaction.

Therefore, while the drive gear 15 is rotating counterclockwise, the planetary gear 16 and the spool shaft gear 13 mesh with each other.

However, since the drive gear 15 reverses itself regardless of the amount of winding of the ink ribbon 11, the drive gear 15 may reverse itself during winding.

When the drive gear 15 reverses and rotates to the right, the planetary gear 16 rotates to the left and immediately attempts to revolve to the right due to the reaction with the arc portion 23a of the friction brake plate 23.

However, at this time, the arm portion 18b of the detection lever 18 prevents the rotation, and the swing lever 17 maintains the state shown by the two-dot chain line in the figure.

Therefore, the planetary gear 16 disengages from the spool shaft gear 13, and ribbon feeding is stopped.

Thereafter, when the drive gear 15 reverses again and starts rotating to the left, the planetary gear 16 meshes with the spool shaft gear 13 again and sends the ink ribbon 11 in the direction of the arrow.

When the ink ribbon 11 is wound in one direction and the eyelet 11a pushes the detection lever 18 as shown in FIG. Evacuate from within the turning trajectory.

However, if the drive gear 15 is still rotating to the left at this time, the planetary gear 16 is in the state shown in FIG.
Furthermore, the ink ribbon 11 is wound onto the left spool.

Therefore, the detection lever 18 is further rotated to the right by the eyelet 11a.

Thereafter, when the drive gear 15 reverses and rotates clockwise, the planetary gear 16 switches to the state shown in FIG. 3, and the ink ribbon 11
is reversed and wound onto the spool on the right.

In the above embodiment of the present invention, the ink ribbon reversal timing is detected by the rotation of the detection lever 18 or 19 using the eyelet 11a of the ink ribbon.
The method is not limited to this, and it is also possible to directly detect the winding diameter of the ink ribbon as shown in FIG. 4, for example.

FIG. 4 will be explained below.

In the figure, reference numerals 28 and 29 indicate detection levers, each of which is pressed against the winding outer diameter portion of the ink ribbon by springs 30 and 31.

Reference numerals 32 and 33 designate restraint levers that are pivotally supported by the detection levers 28 and 29, respectively, and are biased by springs 34 and 35 with driving force for clockwise and counterclockwise rotation. The lever 33 is restrained by the swinging lever 17.

Incidentally, in this figure, parts with the same numbers as in FIGS. 2 and 3 are the same members.

However, other identical members are omitted to simplify the drawing.

Therefore, as the winding diameter of the ink ribbon 11 on the right side decreases, the detection lever 28 and the suppression lever 32 rotate to the right together, and the arm portion 32 a of the lever 32 moves toward the tip portion 17 of the swing lever 17 .
It will now retreat from within the turning trajectory of a.

The other operations are performed in the same manner as those already described, so the explanation will be omitted below.

In the embodiments of the present invention, the case of a serial printer has been briefly described, but it is clear that the present invention is not limited to this, needless to mention other examples.

Since the present invention has the above-described configuration, it is possible to utilize the driving force for reciprocating rotation provided for other purposes, and there is no need to provide a special driving source for feeding the ribbon. be.

Therefore, for example, there is no need for a changeover switch or the like for synchronizing the rotation of the motor with the feeding of the ink ribbon, thereby simplifying the configuration.

[Brief explanation of drawings]

Fig. 1 is a simplified plan view of a conventional example, Fig. 2 is a plan view of an embodiment of the present invention, Fig. 3 is an explanatory diagram of the operation of Fig. 2, and Fig. 4 is an abbreviated plan view of another embodiment. . 11... Ink ribbon, 12.13...
・Spool shaft gear, 15... Drive gear, 1
6... Planetary gear, 18, 19° 28.29...
...Detection lever, 23...Friction brake plate.

Claims (1)

[Scope of Claim for Utility Model Registration] A pair of left and right spool shaft gears, a drive gear whose rotation direction is reversed, and a planet that meshes with the drive gear, rotates, and revolves in the left and right direction as the drive gear is reversed. gears and
The winding direction of the ink ribbon is reversed by reversing the drive gear and causing the planetary gear to revolve so that the planetary gear meshes with the pair of spool shaft gears alternately. The gears are constantly reversed regardless of the winding state of the ink ribbon, and when the vicinity of the end of the ink ribbon is detected, one of the gears retreats from a position where it can prevent the revolution of the planetary gear to a position where it cannot. A pair of detection members are provided such that the drive gear enters from an unblockable position to a blockable position, and even if the drive gear is constantly reversed and the planetary gear always revolves left and right, the planetary gear is The spool shaft gear can be meshed with only one of the spool shaft gears, and when the vicinity of the end of either side of the ink ribbon is detected, the positions of the pair of detection members are switched, thereby detecting the revolution range of the planetary gear. An ink ribbon reversing mechanism characterized by switching to reverse the winding direction of an ink ribbon.