JPS6014603Y2 - Dot printer ribbon switching mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ribbon switching mechanism for a dot printer having a print head in which dot pins are arranged in a horizontal row along a platen.

In a dot printer in which dot pins are arranged in a horizontal row, the ribbon is hung diagonally to increase the printing area relative to the ribbon in order to extend the life of the ribbon.

Further, due to the diversification of forms, it is necessary to print in two colors, black and red, so ribbons consisting of a black ribbon part and a red ribbon part are used.

In such two-color printing, red printing is used much less frequently than black printing, so the red ribbon portion is generally formed to have a smaller width than the black ribbon portion.

When performing black printing, the black ribbon section is positioned diagonally with respect to the dot pins, and when performing red printing, the red ribbon section is positioned horizontally along the dot pins.

Such switching between black and red ribbons is performed by rotating a ribbon holding plate that holds the ribbons.

However, in the past, since the ribbon holding plate was rotated around one end thereof, the center of rotation had to be located far away from the print head, which inevitably resulted in an increase in the size of the printer.

The present invention was devised in view of the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a ribbon switching mechanism for a dot printer that can be miniaturized.

Hereinafter, the present invention will be explained with reference to illustrated embodiments.

The figure shows an embodiment of the ribbon switching mechanism of the dot printer according to the present invention.

A ribbon 1° consisting of a wide black ribbon part 10a and a small red ribbon part 10b has two ribbon spools 1 at both ends.
1 and 124: They are each fixed and wound, and are guided by guide rollers 14 and 15 along the platen 13 surface.

The ribbon spools 11.12 are removably attached to two spool shafts 17.18 fixed to the ribbon holding plate 16, respectively.

Further, the guide rollers 14 and 15 are fixed to the ribbon holding plate 16, but are rotatably supported by idle roller shafts 19 and 20.

A print head 22 having head pins 21 arranged horizontally in a row is disposed above the platen 13 with the ribbon 10 therebetween as shown by a two-dot chain line.

Guide plates 30 and 31 are fixed to the left and right sides of the ribbon holding plate 16, respectively, so as to protrude from the side surfaces opposite to the ribbon side.

The one guide plate 30 has two guide grooves 30a, 3.
0b, but the other guide plate 31 has one guide groove 31a.
are formed respectively, and these guide grooves 30at
aob? 31a respectively have guide rollers 32, 33.
34 are arranged.

The guide rollers 32, 33, and 34 are each fixed to a base plate 35, and are rotatably supported by guide roller shafts 39, 40° 41, which are fixed to the rising portions of idle roller receivers 36, 37, and 38, respectively. .

Here, the three guide grooves 30 at 30 by
31 a has the following relationship.

Since the guide groove 31a is formed longer than the guide groove 30a, the guide plate 31 can slide more than the guide plate 30.

Then, the guide groove 30 on the side remote from the ribbon holding plate 16
When the side walls of the ay 31a are brought into contact with the guide rollers 32 and 34, the ribbon holding plate 16 is moved as shown in FIG.
is diagonal, that is, the ribbon 10 is hung diagonally on the platen 13.

In this case, it is important to determine the inclination angle of the ribbon 10 so that the helad pin 21 is located across the entire width of the black ribbon portion 10a in order to increase the print area relative to the ribbon.

Also, the guide grooves 30a, 31 on the side closer to the ribbon holding plate 16
When the side walls a are brought into contact with the guide rollers 32 and 34, the ribbon holding plate 16 is in a horizontal state as shown in FIG. 2, that is, the red ribbon portion 10b is located in front of the head pin 21.

The guide 130b is formed long enough so that the guide roller 33 does not come into contact with both sides of the guide groove 30b when the ribbon holding plate 16 is swung as described above.

That is, by engaging the guide roller 33 with the guide groove 30b, it serves to prevent the ribbon holding plate 16 from tilting up and down.

The ribbon holding plate 16 also has two guide plates 30.3.
A lever support plate 50 is fixed to the portion between 1 and 1.

A pin 51 is implanted in the lever support plate 50 so as to protrude vertically.A lock lever 52 is attached to the upper protrusion of this pin 51, and a pin 53 implanted in the base plate 35 is attached to the downward protrusion of the pin 51. One end of the shift lever 54 is rotatably supported, respectively.

Then, the guide groove 30 on the side remote from the ribbon holding plate 16
The shift lever 54 is biased clockwise by a spring 55 so that the side walls of the guide rollers 32 and 31a are pressed against the guide rollers 32 and 34, respectively.

Further, a lock plate 56 is fixed to the base plate 35 opposite to one end of the lock lever 52.
The lock lever 52 is biased counterclockwise by a spring 57 so that one end of the lock lever 52 engages with the lock portion 56a.

Further, one end of a connecting plate 60 is rotatably connected to the plunger 58a of the solenoid 58 by a pin 59, and the other end of a connecting plate 60 is rotatably connected to the lock lever 52 by a pin 61.

The plunger 58a normally protrudes as shown in FIG. 1, and in this state is engaged with the lock portion 56a by the biasing force of the spring 57 at one end of the lock lever 52.

Further, when one end of the lock lever 52 is engaged with the lock portion 56a, the lever support plate 50 is attached to the lock lever 5.
The engagement pin 6 is placed opposite the other end of 2 with a certain gap maintained.
2 have been planted.

Next, the operation of this mechanism having such a configuration will be explained.

When printing in black, use solenoid 5 as shown in Figure 1.
8 is not excited, and the plunger 58a is in a protruding state.

In this state, as described above, the lock lever 52 engages with the lock portion 56a of the lock plate 56, and the biasing force of the spring 55 causes the guide groove 30 on the side remote from the ribbon holding plate 16 to
Since the side walls of the ribbons a and 31a are in pressure contact with the guide rollers 32 and 34, the ribbon holding plate 16 is tilted and
That is, the ribbon 10 is hung diagonally so that the black ribbon portion 10a is located at a position corresponding to the head pin 21.

Next, when printing in red, the plunger 58a is retracted in the direction of arrow A when the thread maid 58 is energized as shown in FIG.

As a result, the lock lever 52 first rotates clockwise about the pin 51 and is unlocked from the lock portion 56a.

Thereafter, the lock lever 52 engages with the retaining pin 62, and the solenoid 58, together with the lever support plate 50, resists the spring 55.
pulled to the side.

As a result, the guide plate 3 fixed to the ribbon holding plate 46
The guide i30 at 31a of 0°31 slides along the guide rollers 32 and 34, respectively, and the ribbon holding plate 1
The side walls of the guide grooves 30a, 31a on the side closer to the groove 6 are pressed against the guide rollers 32, 34, respectively.

As mentioned above, since the guide groove 31a is formed longer than the guide *30a, the ribbon holding plate 16 moves toward the solenoid 58, and the distance between the guide rollers 32 and 34 and the length of the guide grooves 30a and 31a It rotates by a rotation angle corresponding to the ratio of the difference between.

That is, the ribbon holding plate 16, i.e., the ribbon 10, performs an action as if it were rotating around the fulcrum 0, which is far away from the print head 22, and as a result, the ribbon holding plate 16 is in a horizontal state, and the red ribbon portion 10b is flattened. It is located in front of the rad pin 21.

In the above embodiment, in the case of red printing, the ribbon 10
Although the dot pin 21 is used in a horizontal position, it may be used in an inclined position as long as the dot pin 21 fits within the width of the red ribbon portion 10b.

In addition, the present invention is not limited to ribbons of two colors, black and red, but can also be applied to a case where a black ribbon is used in half, that is, when one half reaches the end of its service life, it is switched and the remaining half is used.

As is clear from the above description, according to the ribbon switching mechanism of the dot printer according to the present invention, the ribbon holding plate is shifted at a position close to the print head, so that a compact dot printer can be obtained.

[Brief explanation of drawings]

The figures show an embodiment of the ribbon switching mechanism of the dot printer according to the present invention, in which Figure 1 is a plan view with black printing, Figure 2 is a plan view with red printing, and Figure 3 is the left side of Figure 2. It is a diagram. 10... Ribbon, 16... Ribbon holding plate, 21... Dot pin, 22... Print head, 30, 31... Guide plate ,30a,
31a...Guide groove, 32.34...
guide roller.

Claims (1)

[Scope of utility model registration request] A ribbon switching mechanism for a dot printer that includes a print head in which a plurality of dot pins are arranged horizontally, and switches a ribbon portion corresponding to a dot pin by moving a ribbon holding plate that holds a ribbon disposed along the front surface of the dot pin, Guide plates are provided on the left and right sides of the ribbon holding plate, protruding from the side opposite to the ribbon side, and a guide groove is formed in each of the protruding portions of the two guide plates in a plane parallel to the ribbon surface, and A driving means for disposing guide members provided on the base plate in each guide groove, and moving the ribbon holding plate so that the ribbon side and the side remote from the ribbon side of the two guide grooves alternately abut the guide members. are provided on the base plate, and the two guide grooves are formed so that when the ribbon holding plate is moved by the driving means, the one guide plate moves more than the other guide plate. Ribbon switching mechanism for dot printers.