JPH01226385A - Ribbon lift mechanism of typewriter - Google Patents

Abstract

PURPOSE:To reduce manufacturing cost by reducing the number of parts and to reduce the load of a worker by simplifying control work, by a method wherein a stopper member is engaged with and detached from the intermediate part of a cam follower. CONSTITUTION:With the forward rotation of a ribbon lift cam 7, a cam follower 21 is moved so as to follow the first cam part to be introduced into an escape part 13 and, at this time, a stopper member 22 is engaged with the intermediate part of the cam follower 21 and the cam follower 21 is prevented from being introduced into the second cam part 12 from the escape part 13. Therefore, the printing ribbon R on a holder 3 is held at a printing position. When the cam follower 21 is moved so as to follow the second cam part 12 with the forward rotation of the ribbon lift cam 7, the stopper member 22 is separated from the intermediate part of the cam follower 21 prior to the movement of said cam follower 21 and a correction ribbon C is arranged at the printing position on the basis of the action of the second cam part 12. As mentioned above, the stopper member is engaged with and detached from the intermediate part of the cam follower.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention is a type in which one of the printing ribbons and the correction ribbon is selectively placed at the printing position by swinging a holder that supports both ribbons. This invention relates to a lighter ribbon lift mechanism.

(Prior Art) Conventionally, as a ribbon lift mechanism for a typewriter, there is one described in, for example, Japanese Patent Laid-Open No. 158491/1983. In this conventional mechanism, during a single printing operation, as the cam body rotates, the printing ribbon on the holder swings from the rest position to the printing position through the engagement of the ribbon lift cam provided on one side of the cam body and the cam follower of the holder. and during continuous printing operation, the stopper is engaged with the locking piece of the holder by the action of a stopper operating cam provided on the other side of the cam body, and the printing ribbon on the holder is held at the printing position; During the correction printing operation, the stopper is released from the locking piece by the action of the stopper operating cam,
Further swinging of the holder is allowed, so that the correction ribbon disposed below the printing ribbon is placed at the printing position.

(Problem to be Solved by the Invention) However, in the above conventional mechanism, the cam follower that engages with the ribbon lift cam and the locking piece that engages with the stopper are arranged at a predetermined interval. When assembling them, it is necessary to individually position the cam follower and the locking piece to ensure placement accuracy at the printing position of each ribbon, and there is a problem that the adjustment becomes extremely complicated. .

This invention was made to solve the above problems, and its first purpose is to reduce the number of parts by using the cam follower as a locking piece, thereby reducing manufacturing costs and reducing adjustment work. To provide a ribbon lift mechanism that can be simplified and reduce the burden on a worker. or,
The second purpose is to provide a ribbon lift mechanism that does not require a dedicated drive mechanism to operate a stopper member that holds the printing ribbon at the printing position, and can further reduce manufacturing costs. be.

(Means and operations for solving the problem) In order to achieve the above object, the present invention supports both ribbons so that the correction ribbon is positioned below the printing ribbon, and moves both ribbons from a lower rest position. a holder that is swung and biased toward the printing position in order to be selectively placed in the upper printing position;
A first cam part for moving the printing ribbon from the rest position to the printing position, a second cam part for moving the correction ribbon from the rest position to the printing position, and a relief part continuous to both cam parts on one side. a ribbon lift cam which is formed in a shape and is rotatable in forward and reverse directions, and is connected to the holder at one end thereof, and is engaged with the ribbon lift cam at the other end to follow the rotation of the ribbon lift cam. The cam follower is detachably disposed between the cam follower to be moved and the middle part of the cam follower, and when the cam follower is moved following the first cam part and introduced into the relief part by the forward rotation of the ribbon lift cam, the cam follower is moved from the relief part. engaging a cam follower to hold the print ribbon in the print position by prohibiting the print ribbon from being introduced into the second cam portion;
A stopper member is provided that separates from the cam follower prior to movement when the cam follower moves following the second cam part due to forward rotation of the ribbon lift cam.

Therefore, when the cam follower is moved following the first cam part and introduced into the relief part with the forward rotation of the ribbon lift cam, the stopper member is engaged with the intermediate part of the cam follower, and the cam follower is moved from the relief part. It is prohibited from being introduced into the second cam part. Therefore, the printing ribbon on the holder is held at the printing position. Further, when the cam follower is moved following the second cam part with the forward rotation of the ribbon lift cam, the stopper member separates from the intermediate part of the cam follower prior to the movement, and the stopper member is separated from the middle part of the cam follower based on the action of the second cam part. the correction ribbon is placed at the printing position. In this way, since the stopper member is engaged with and detached from the intermediate portion of the cam follower, there is no need to provide a separate member from the cam follower that is engaged by the stopper member in order to hold the printing ribbon in the printing position.

Further, if the stopper member is moved by a stopper moving cam formed on the other side of the ribbon lift cam, there is no need to provide a special device such as an electromagnetic solenoid exclusively for driving the stopper member.

(Example) Hereinafter, an example embodying the present invention will be described in detail with reference to the drawings. As shown in Fig. 1(a) and Fig. 3,
A holder 3 is swingably supported by a support shaft 4 on a carriage 2 that is moved along a platen l, and is urged to swing clockwise in the figure by a spring 3a. A ribbon cassette 5 containing a printing ribbon R and a spool 6 wound with a correction ribbon C are attached to the holder 3, and as the holder 3 swings, the exposed portions of each ribbon R and C face the platen 1. placed in position.

A ribbon lift cam 7 is rotatably supported on the carriage 2 by a support shaft 8, and a step motor 10 and a transmission gear 40, which can rotate in forward and reverse directions, are attached to the carriage 2.
The rotation of the ribbon lift cam 7 is transmitted via the drive gear 10a on the output shaft and the transmission gear 40 to the driven gear 9 integrally formed with the ribbon lift cam 7, and the ribbon lift cam 7 moves in the direction of the arrow in FIG. Rotated in the direction of the arrow. On the inner surface of the ribbon lift cam 7, as shown in FIG.
a cam portion 11 and a second cam portion 12 for correction ribbon lift whose diameter increases continuously from the inner wall on the outer peripheral side of the first cam portion 11;
, and an equiradial relief part 13 parallel to the second cam part 12 and continuous with the inner wall on the center side of the first cam part 11 is formed in the shape of a deep groove. Furthermore, ribbon lift cam 7
is formed with an equal radius part 14 continuous to the relief part 13, and an equal radius inclined part 15 continuous with the equal radius part 14 and whose cam groove depth gradually decreases, and furthermore, an inclined part 15 is formed. 1
A shallow groove portion 16 is formed between the first cam portion 5 and the first cam portion 11 .

On the other hand, as shown in FIGS. 2 and 3, a connecting piece 17 made of synthetic resin is screwed onto the holder 3, and a cylindrical support part 18 is integrally formed on the connecting piece 17. As shown in FIG. 4, a retaining pin 19 is slidably attached to the support portion 18 and is biased by a spring 20 in the projecting direction. Then, the cam follower 2 is moved by the support portion 18 and the engagement pin 19
1 is constructed, and based on the engagement between the engagement pin I9 and each cam part '11, 12, etc., as the ribbon lift cam 7 rotates, the printing ribbon R and the correction ribbon C move to the position shown in FIG. The same figure (b) is shown from the lower rest position.

It is selectively moved to the upper printing position shown in (C).

A two-armed stopper member 22 is provided at the base end of the support shaft 8.
is swingably supported at its intermediate portion, and at its upper end, a regulating piece 23 that can be engaged and detached from above is integrally provided on the outer periphery of the support portion 18, and a long hole 24 is formed at its lower end. has been done. On the lower side of the ribbon lift cam 7, there are a pair of operating parts 25a and 25b located on both the inner and outer sides of the ribbon lift cam 7.
The lever 25 equipped with a support shaft 26 at its intermediate shaft portion 25c
A connecting pin 27 that is swingably supported by and protrudes from the inner actuating portion 25a is connected to the long hole 2 of the stopper member 22.
A support portion 25d and a follower pin 28 having the same structure as the cam follower 21 are disposed at the tip of the outer actuator 6B25b. As the lever 25 swings, the stopper member 22 moves to an operating position where it can engage with the support portion 18 of the cam follower 21 as shown by the dotted line in FIG. support part 18
and an inactive position away from the

A stopper moving cam portion 29 is formed on the outer surface of the ribbon lift cam 7, and the following pin 28 is attached to the cam portion 29.
is engaged. Further, as shown in FIG. 6, the stopper moving cam portion 29 includes a third cam portion 30 formed in an equal radius shape and a deep groove shape except for a part to hold the stopper member 22 in the operating position, and a third cam portion 30 formed in a deep groove shape except for a part of the stopper member. A fourth cam part 31 is provided, which is concentric with the third cam part 30 and formed into a deep groove shape except for a part, in order to hold the second part in the non-operating position. Also, in order to introduce the follower pin 28 from the third cam part 30 to the fourth cam part 31 when the ribbon lift cam 7 rotates in the opposite direction, the depth of the groove gradually decreases toward the fourth cam part 31. The second introduction part 33 has a groove whose depth gradually decreases toward the third cam part 30 in order to introduce from the fourth cam part 31 to the third cam part 30.

Further, the third cam portion 30 is formed with an oblique portion 30 a whose groove depth gradually decreases toward the first introduction portion 32 , and the fourth cam portion 31 is formed with an inclined portion 30 a that gradually decreases in depth toward the first introduction portion 32 . A diagonal portion 31a is formed in which the depth of the groove gradually decreases toward the groove. Then, both ends of the first introduction part 32 and the fourth cam part 31
A step 34.35 is formed at the boundary between the second introduction section 33 and the third cam section 30 and the oblique section 30a, and a step 36.37 is formed between both ends of the second introduction section 33 and the third cam section 30 and the oblique section 31a. .

Next, the operation of the h-type writer constructed as described above will be explained. FIG. 1 (a) shows that the follower pin 2B is located at the home position in the third cam section 30 of the stopper moving cam section 29 (Pi (see FIG. 6)), and the stopper member 22 is actuated via the lever 25. At this time, the retaining button 19 of the cam follower 21 is located at the home position HP2 (see FIG. 5) in the first cam portion 11 of the ribbon lift cam 7. ,
The correction ribbon C and the printing ribbon R on the holder 3 are placed in the rest position.

In this state, when a print signal is input by pressing a predetermined character key, the motor 10 moves the ribbon lift cam 7 at a predetermined angle in the direction of the arrow in FIGS. 1(a), 5, and 6. It is rotated forward by θ1. At this time, the stopper member 22 is held at the operating position by the action of the third cam portion 30. Further, the retaining pin 19 is operated according to the shape of the first cam portion 11, and the holder 3 is swung clockwise in FIG. 1(a) based on the biasing force of the spring 3a. As shown in b), the outer periphery of the middle part of the cam follower 21 (support part 18)
is engaged with the stopper member 22. Thereby,
The printing ribbon R is arranged at the upper printing position. In this state, a printing hammer (path shown) is operated and the printing hammer strikes the printing type Wa on the printing wheel W, thereby printing characters on the printing paper on the platen 1.

If the next character key is not pressed down by the time a predetermined period of time has elapsed, the motor reversely rotates the ribbon lift cam 7 by θ1 in the opposite direction of the arrow in FIG. 1(b). By the action of the first cam portion 11, the engagement pin 19 is returned to the home position HP2, the printing ribbon R is returned to the lower rest position, and the single printing operation is completed.

On the other hand, when the next character key is pressed down continuously following the previous character key before the predetermined time has elapsed, the ribbon lift cam 7 continues to rotate by the angle 01, and then rotates by the predetermined angle θ3. It is continuously rotated in the forward direction. At this time, the stopper member 22 is held at the operating position by engagement between the follower pin 28 and the third cam portion 30 having the same radius. Therefore,
The engagement pin 19 of the cam follower 21, which has been moved following the first cam part 11, is prohibited from being introduced into the second cam part 12, and the cam follower 21 has a relief part 13, an equal radius part 14. Diagonal portion 15. It is sequentially introduced into the shallow groove portion 16 and the first cam portion 11 and relatively moved along an equiradial trajectory. As a result, the printing ribbon R is held at the printing position,
A continuous printing operation is performed.

At the end of the continuous printing operation, if the next character key is not operated within a predetermined time, the current locking pin 19
Position on ribbon lift cam 7 and home position HP
2 is calculated, the motor 10 rotates backward by that amount, the ribbon lift cam 7 starts to rotate backward, and the printing ribbon R is returned to the rest position.

On the other hand, if the correction key is operated after printing an error, the ribbon lift cam 7 moves in the opposite direction by a predetermined angle θ2.
is rotated only. Then, the follower pin 28 is introduced from the third cam section 30 to the fourth cam section 31 by the action of the step 35 and the first introduction section 32, and based on the introduction operation, the lever 25
The stopper member 22 is swung from the working position shown in FIG. 1(b) to the non-working position shown in FIG. 1(C) through the
The cam follower 21 is separated from the support portion 18 . At this time,
The engagement pin 19 of the cam follower 21 is moved from the home position HP2 in the first cam part 11 to the starting end side of the first cam part 11.

Subsequently, when the ribbon lift cam 7 is rotated by a predetermined angle θ4 in the direction of the arrow, the follower pin 28 is moved along the fourth cam portion 31, and the stopper member 22 is held in the non-operating position. Further, after the cam follower 21 is moved along the first cam part 11 without engaging with the stopper member 22, it is reliably introduced into the second cam part 12, and the holder 3 is moved by the action of the second cam part 12. The upper correction ribbon C is placed at the printing position. Thereafter, the printing hammer is activated to erase the erroneously printed characters.

After this erasing operation, the ribbon lift cam 7 moves in the opposite direction to the angle θ4. The correction ribbon C is reversely rotated by the difference of θ2, and the correction ribbon C is returned to the rest position by the action of the second and first cam portions 12.11, and the follower pin 28 moves to the step 3.
7 and the second introduction part 33, the stopper member 22 is introduced from the fourth cam part 31 to the third cam part 30, and accordingly, the stopper member 22 is swung back to the operating position.

As described above, in this embodiment, the movement of the cam follower 21 to the relief part 13 is directly prohibited by the stopper member 22 during continuous printing operation, and the member to be locked by the stopper member 22 is separated from the cam follower 21. Since there is no need to provide the holder 3 with the holder 3, the number of parts can be reduced and manufacturing can be done at low cost. Further, in order to press the engagement pin 19 and the follower pin 28 against the first cam portion 11 etc. and the groove bottom of the stopper moving cam portion 29, a coil spring 20 is used.
Since it uses a leaf spring, it can be manufactured at a lower cost than when using a leaf spring.

Furthermore, in order to accurately position the printing ribbon R and the correction ribbon C at preset printing positions, a cam follower 21 is required.
When installing the correction ribbon C, the printing position of the printing ribbon R is adjusted by adjusting the position, and the printing position of the correction ribbon C is also determined depending on the positional relationship between the cam follower 21 and the ribbon lift cam 7. There is no need to adjust the printing position for each of the ribbons R and C, which simplifies the adjustment work and reduces the burden on the operator.

Note that this invention is not limited to the above embodiments,
In order to switch the arrangement position of the stopper member 22, it is also possible to connect an electromagnetic solenoid or the like to the stopper member 22.

(Effects of the Invention) As detailed above, in this invention, the stopper member is engaged with and detached from the middle part of the cam follower, so the cam follower also serves as a locking piece, reducing the number of parts and reducing manufacturing costs. In addition, it is possible to simplify the adjustment work and reduce the burden on the operator. Furthermore, if a stopper moving cam portion is formed on the other side of the ribbon lift cam in order to move the stopper member, there is no need to provide a dedicated drive mechanism for the stopper member, and manufacturing costs can be further reduced.

[Brief explanation of the drawing]

FIG. 1(a) is a partial side view showing the main parts of a typewriter embodying the present invention, FIG. 1(b) is a partial side view during printing operation, and FIG. 1(c) is during correction printing operation. A partial side view of FIG. 2, a partial plan view of the beam bong lift mechanism,
Fig. 3 is a partial front sectional view, Fig. 4 is a partially enlarged sectional view showing the cam follower, Fig. 5 is an enlarged view of the ribbon lift cam seen from the front, and Fig. 6 is an enlarged front view of the stopper moving cam section. be. 3...Holder, 7...Ribbon lift cam, 11.
...First cam part, 12... Second cam part, 13... Relief part, 21... Cam follower, 22... Stopper member, 29... Stopper moving cam part, R... Printing Ribbon, C... Correction ribbon. Patent applicant Brother Industries, Ltd. Agent
Patent Attorney On 1) Hironobu Figure 2 Figure 4 U

Claims (1)

[Claims] 1. Both ribbons (R, C) are supported so that the correction ribbon (C) is located below the printing ribbon (R), and both ribbons (R
, C) from the lower rest position to the upper printing position, and the holder (3) is biased toward the printing position, and the printing ribbon (R) is moved from the rest position to the printing position. A first cam part (11) for moving the correction ribbon (C) to the printing position, and a second cam part (11) for moving the correction ribbon (C) from the rest position to the printing position.
12) and a relief part (11, 12) continuous to both cam parts (11, 12)
13) is formed on one side and is rotatable in forward and reverse directions; and one end thereof is connected to the holder (3), and the other end is connected to the ribbon lift cam (7). (7) and a cam follower (21) that is moved in accordance with the rotation of the ribbon lift cam (7); and the cam follower (21).
The cam follower (2
1) is moved following the first cam part (11) by the forward rotation of the ribbon lift cam (7) and introduced into the relief part (13). ) engages the cam follower (21) to hold the printing ribbon (R) in the printing position by prohibiting the printing ribbon (R) from being introduced into the printing position;
The cam follower (
21) is provided with a stopper member (22) that separates from the cam follower (21) when the cam follower (21) is moved following the second cam part (12). mechanism. 2 The stopper member (22) is a stopper moving cam portion (2) formed on the other side of the ribbon lift cam (7).
9). The typewriter ribbon lift mechanism according to claim 1, wherein the ribbon lift mechanism is moved by: 9).