JPH0480836B2 - - Google Patents

Description

TECHNICAL FIELD The present invention relates to printers, and more particularly to printers equipped with an eraser ribbon metering mechanism.

Prior Art In addition to the ink ribbon for printing, an erasing ribbon is provided, and the erasing ribbon is positioned above the printed characters, and the printing operation is performed using the same type of characters as the printed characters. Printers are known that are equipped with an erasing ribbon that covers the characters with ink of the same color as the printing paper or peels off the printed characters.

Conventional printers of this type have a configuration in which the used erasing ribbon is wound around a take-up reel, and the take-up reel is rotated at a constant angle to wind up one character's worth of erasing ribbon. .

However, if such a configuration is adopted, as more used erasing ribbon is wound around the take-up reel, the diameter of the take-up reel increases, and when the reel is rotated at a certain angle, erasing occurs between the beginning and the end of the winding. This results in a large change in the amount of ribbon feed.

In other words, if the amount of erasing ribbon required to erase one character is adjusted to the beginning of the take-up reel,
At the end of the roll, more ribbon is wound than necessary, resulting in unnecessary consumption of the erasing ribbon.

In order to solve this problem, a configuration has been proposed in which a cam or the like is used to change the rotation angle of the take-up reel.

Each of the printers having such a configuration has its own characteristics, but there is room for improvement in that the structure is complicated.

Purpose The present invention was made in order to eliminate the above-mentioned drawbacks of the conventional technology.
It is an object of the present invention to provide a printer configured to reliably feed an erasing ribbon in a fixed amount.

Embodiments Hereinafter, details of the present invention will be explained based on embodiments shown in the drawings.

FIG. 1 and subsequent drawings explain one embodiment of the present invention. In the drawings, reference numeral 1 indicates a carriage, which is disposed opposite to a platen 2. As shown in FIG. A recording paper 3 is wound around the platen 2.

A type wheel 4 and a print hammer 5 are arranged at the end of the carriage 1 on the platen 2 side.

The carriage 1 is slidably guided along guide rails 6, 6 arranged parallel to the platen 2.

Erasing arms 8, 8 are arranged on both sides of the carriage 1, and the rear ends of these erasing arms 8, 8 are connected to a shaft 8a rotatably supported on the carriage 1.
is fixed at both ends.

A supply reel 9 for the erasing ribbon 7 is rotatably supported at the tip of one of the erasing arms 8, which is located on the left side in FIG. 8b is fixed.

A rotary lever 10 is rotatably supported at one end via a shaft 11 at the front end of the support plate 8b.

A ratchet wheel 12 and a take-up reel 13 are coaxially supported on the support shaft 11 of the rotating lever 10.

Incidentally, a clutch means (not shown) is provided between the take-up reel 13 and the latchet wheel 12, and when a rotational force of a certain level or more is applied, the take-up reel 13 is moved over the latchet wheel 12.
It has a structure that allows it to slip against the ground.

A return spring 14 is stretched between the free end side of the rotating lever 10 and a pin 8c protruding in the middle of the erasing arm 8. As the center, it constantly provides rotational force in the counterclockwise direction.

A ratchet 15 is attached to the pin 1 on the rotating lever 10.
6, and is rotatably supported on a shaft via the ratchet wheel 12, and meshes with the ratchet wheel 12. A spring 17 is stretched between the ratchet 15 and a pin protruding in the middle of the rotary lever 10, and constantly applies a force in the direction of meshing with the ratchet wheel 12.

On the other hand, on the support plate 8b and the ratchet 1
A detent ratchet 18 is rotatably supported on the opposite side of the ratchet wheel 12 through a pin 19, and a spring 20 tensioned between the support plate 8b and the ratchet wheel 12 allows the ratchet 18 to be rotated in the direction in which it engages with the ratchet wheel 12. is given the power of

Furthermore, one end of a feed lever 21, which is another rotary lever, is rotatably supported on the support plate 8b via a pin 22, and an arm 8d extending from its free end to the tip of the support plate 8b. A spring 23 is stretched between the feed lever 21 and the first spring 23.
In the figure, a counterclockwise rotational habit is given.

A ribbon presser 24 is provided protrudingly on the feed lever 21, and a feed pawl 25 is rotatably supported by a pin 26 in line with the ribbon presser 24.

A spring 27 is stretched between the free end side of the feed claw 25 and the feed lever 21, and the feed claw 25 is given a force to press the erasing ribbon 7 toward the ribbon presser 24 side.

On the other hand, a protruding piece 8e is provided on one side of the erasing arm 8, and a solenoid 28 is fixed on a protruding piece 1a that is protruded from the side surface of the carriage 1 while facing the protruding piece 8e. , the rod 28a
The tip of the protrusion e is in constant contact with the lower surface of the protrusion e.

On the other hand, a pin 1b is provided protruding from the side surface of the carriage 1, and the base end of a push rod 29 is rotatably supported on this pin 1b.

The push rod 29 is bifurcated, and the tip of one arm 29a is located above the support plate 8b, facing the rotation lever position 0.

The tip of the other arm 29b passes under the support plate 8b, extends upwardly from the edge of the support plate 8b on the platen 2 side, and faces the feed lever 21.

Note that the erasing ribbon 7 is unwound from the supply reel 9, changes its direction when it comes into contact with a guide roller 30 attached to the tip of one erasing arm 8, and then changes its direction to the guide roller 3 that is rotatably supported on the tip of the arm 8d of the support plate 8b.
1 and guided to the take-up reel 13 side.

Next, the operation of this embodiment configured as above will be explained.

First, in the printing state, as shown in FIG. 2, the current to the solenoid 28 is cut off.
Since the rod 28a is lowered, the two eraser arms 8, 8 have their tips lowered due to their own weight, and the eraser ribbon 7 escapes downward from between the type wheel 4 and the recording paper 3, and normally does not interfere with printing.

By the way, in this state, the push rod 29 is lowered together with the support plate 8b that is integrated with the erasing arm 8, but the length of the push rod 29 is shorter than the length of the erasing arm 8, and the pin that is its pivot is shorter than the length of the erasing arm 8. 1b is located closer to the platen 2 than the support shafts 8a of the erasing arms 8, 8, so as the support plate 8b descends, the upper arm 29a of the push rod 29 moves forward on the support plate 8b. Rotating lever 10 and return spring 1
4, and push the rotating lever 10 against the shaft 2.
1 in the clockwise direction in the figure.

At this time, the ratchet 15 also moves together with the rotating lever 10, but its tip slips on the circumferential surface of the ratchet 12, and the ratchet 12 is prevented from rotating by the ratch 18 for preventing rotation, so that it can be moved to its position. do not change.

On the other hand, the tip of the lower arm 29b of the push rod 29 is moved away from the feed lever 21 as the support plate 8b is tilted.

Therefore, the feed lever 21 is rotated counterclockwise in the figure by the tension of the spring 23 around the shaft 22, and the feed claw 25 is rotated clockwise around the pin 26 in the figure by the force of the spring 27. However, the tensile force of the spring 27 is weakened, and the holding force against the erasing ribbon 7 is almost eliminated. In other words, no binding force is applied to the erasing ribbon 7.

Next, the erased state will be explained.

If you want to erase the printed characters, press the erase button (not shown) and the solenoid 28
is driven and the rod 28a protrudes.

As a result, the erasing arms 8, 8 are
is rotated counterclockwise about the support shaft 8a as shown in FIG. 1 and lifted.

Therefore, the erasing ribbon 7 is placed between the type wheel 4 and the recording paper 3, and is in an erasing standby state.

On the other hand, as the erasing arm 8 rotates, the support plate 8b rises. At this time, the arms 29a and 29b of the push rod 29
Since the tips of the push rods 29 are in contact with the support plate 8b, the push rods 29 are also rotated upward.

As a result, the arm 29a moves away from the support plate 8b toward the front, contrary to the movement of the support plate 8b described above when the support plate 8b is lowered, and the tip of the arm 29b reversely moves toward the support plate 8b.
It will move towards the center of.

As a result, the rotation lever 10 is moved by the return spring 1.
4, it is rotated counterclockwise about the shaft 11 in FIG.

At this time, the ratchet 15 as a whole is rotated counterclockwise, and the ratchet wheel 12 is moved one pitch counterclockwise in the figure.

When the ratchet wheel 12 rotates counterclockwise, the anti-return ratchet 18 slips against the circumferential surface of the ratchet wheel 12.

On the other hand, since the feed lever 21 is pushed by the tip of the arm 29b, it is rotated clockwise about the shaft 22 in FIG. As a result, the spring 27
extends, attracts the feeding claw 25 toward the ribbon presser 24, and strongly presses the erasing ribbon 7.

Therefore, the erasing ribbon held between the feed claw 25 and the ribbon presser 24 is pulled toward the take-up reel 13 by one character as the feed lever 21 rotates.

This retracting operation of the erasing ribbon 7 for one character, the rotation of the ratchet wheel 12 for one pitch, and the rotation of the take-up reel 13 occur simultaneously, and the retracted erase ribbon 7 is taken up on the take-up reel 13. .

In this way, if it is desired to perform continuous erasing in which the erasing ribbon 7 is always wound up by one character in conjunction with the upward movement of the erasing arm 8, the above-described operation can be repeated.

By the way, as the erasing ribbon 7 is taken up on the take-up reel 13, its diameter increases, but a force is applied to the supply reel 9 in the opposite direction to the ribbon feeding direction, and this force is applied to the take-up reel 13. This is greater than the holding force of the clutch provided on the reel 13 side.

Therefore, even if the winding diameter of the erasing ribbon becomes larger, the take-up reel 13 does not wind up the erasing ribbon excessively, and the ribbon can be unrolled by the feed pawl 25.
After winding up the erasing ribbon for the characters, the clutch on the take-up reel 13 side slips.

Since the present embodiment is configured as described above, the erasing ribbon can always be wound up for one character in conjunction with the rising movement of the erasing arm, and the erasing ribbon is not wasted.

Further, since the erasing ribbon winding mechanism has a simple configuration, it is easy to manufacture and does not cause any failures.

Effects As is clear from the above, according to the present invention, there is provided a solenoid for rotating a pair of erasing arms between an erasing position and a printing position in response to an erasing command, and a solenoid provided on one of the erasing arms. a take-up reel for winding up the erasing ribbon; a push rod that is linked to the rotation of the erasing arm on the side where the take-up reel is provided;
a feed lever having a feeding claw for the erasing ribbon and rotating a distance equivalent to the length of one character of the erasing ribbon in response to interlocking with the push rod; and a feed lever that rotates coaxially with a shaft to which the take-up reel is attached. A ratchet wheel is attached to the take-up reel and the clutch via the clutch, the ratchet wheel being rotatably supported on a shaft and rotated by the push rod, and the ratchet wheel is provided on the other side of the erasing arm, and the ratchet wheel is rotatably mounted on the take-up reel and rotated by the push rod. a supply reel that holds an erasing ribbon and supplies the erasing ribbon, and the push rod rotates the feed lever in response to a rotational movement of the erasing arm between an erasing position and a printing position. By doing this, the used part of the erase ribbon is wound onto the take-up reel one character at a time, regardless of the amount of ribbon taken up by the take-up reel, so that the erase arm moves to the erase position when erasing. Since the erasing ribbon can be reliably wound up for one character in conjunction with the rotating operation of rotating the erasing ribbon to the printing position, there is an excellent effect that wasteful consumption of the erasing ribbon is avoided.

[Brief explanation of drawings]

The figure explains one embodiment of the present invention.
Figure 2 is a perspective view during erasing operation, Figure 2 is a perspective view during printing, Figure 3 is a plan view illustrating the erasing ribbon being wound up, and Figure 4 is a plan view showing the erasing ribbon not being wound up. be. 1... Carriage, 2... Platen, 7... Erasing ribbon, 8... Erasing arm, 9... Supply reel, 10... Rotating lever, 12... Ratchet wheel, 15, 18... Ratchet, 21 ...Feed lever, 24...Ribbon presser foot, 25...Feed claw, 29...Push bar.

Claims (1)

[Claims] 1. A solenoid for rotating a pair of erasing arms between an erasing position and a printing position in response to an erasing command, and a take-up reel provided on one of the erasing arms for winding an erasing ribbon. and a push rod that is linked to the rotation of the erasing arm on the side where the take-up reel is provided, and a feeding claw for the erasing ribbon, and the length of the erasing ribbon is adjusted by one character in accordance with the interlocking movement of the push rod. a feed lever that rotates a distance equivalent to the length of the take-up reel; a ratchet wheel; a supply reel for supplying the eraser ribbon, the supply reel being disposed on the other side of the eraser arm and holding the eraser ribbon with a force greater than the holding force of the clutch;
The push rod rotates the feed lever in response to the rotational movement of the erasing arm between the erasing position and the printing position, regardless of the amount of ribbon taken up on the take-up reel. , a printer characterized in that the used portion of the erasing ribbon is wound up on the take-up reel one character at a time.