JPH068599A - Printer - Google Patents

Abstract

PURPOSE:To provide a printer capable of certainly performing the take-up operation of an erasing ribbon accompanied by erasing operation. CONSTITUTION:The ratchet wheel 78 connected to an erasing ribbon taking-up spool is pivotally mounted on a holder member 32 and a ratchet pawl member 79 is pivotally mounted on the auxiliary frame 33 of a carriage and a ratchet pawl 79a is elastically biared by a spiral spring 87 so as to be always engaged with the ratchet wheel 78. Therefore, regardless of the magnitude of the play quantity in the pivotal. support mechanism pivotally supporting the holder member 32 so as to revolve the same up and down, the ratchet pawl 79a and the ratchet wheel 78 are always engaged with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing wheel type printing apparatus, and more particularly, to step-feed an erasing ribbon when a holder member having a printing ribbon and an erasing ribbon is switched between a printing position and an erasing position. Regarding things.

[0002]

2. Description of the Related Art Conventionally, a type wheel type electronic typewriter capable of printing and erasing characters by providing a printing hammer, a type wheel, a printing ribbon, an erasing ribbon and a drive mechanism for these on a carriage is well known. In this type of electronic typewriter, a holder member equipped with a printing ribbon or an erasing ribbon is placed between the printing position where the printing ribbon faces the printing hammer during printing and the erasing position where the erasing ribbon faces the printing hammer during erasing. The position switching mechanism for switching positions, the print hammer drive mechanism, and the print ribbon winding mechanism are each driven by a dedicated motor.

By the way, the applicant of the present application filed Japanese Patent Application No. 3-12.
In the specification and drawings attached to the application of No. 949, the position switching mechanism of the holder member, the print hammer drive mechanism, the print ribbon winding mechanism and the erasing ribbon winding mechanism are driven by one motor provided in the carriage body. Therefore, an electronic typewriter which can reduce the manufacturing cost and can make the carriage compact has been proposed. Therefore, in this electronic typewriter, the drive shaft of the motor is integrally provided with a printing cam for driving the printing hammer and a raising cam for raising the holder member to the erasing position.
A reference cam that holds the holder member at the print position, an outer peripheral cam that holds the erase member at the erasing position, and inclined first and second inclined cams that connect the reference cam and the outer peripheral cam are formed on the ascending cam. Further, a driven pin that slides on the ascending cam is attached to the holder member, and the driven pin is slid on the reference cam by the forward rotation of the motor to hold the holder member at the printing position. While the printing hammer is used for printing, the driven pin is slid to the outer peripheral cam through the first and second inclined cams by the reverse rotation and the forward rotation of the motor at a predetermined angle to hold the holder member at the erasing position. In this state, the erase operation is performed.

Moreover, after the erasing operation, the driven pin is slid from the outer peripheral cam to the reference cam via the second inclined cam by the reverse rotation of the motor and the own weight of the holder member to lower the holder member to the original printing position. An erasing ribbon winding mechanism for winding the erasing ribbon by this downward rotation is provided. That is, a ratchet wheel for rotating the erasing ribbon take-up spool is provided on the holder member, while a ratchet pawl engageable with the ratchet wheel is attached on the carriage side, and when the holder member descends to the original printing position. The ratchet pawl rotates the ratchet wheel by one tooth to step the erase ribbon by a predetermined amount.

[0005]

As described above, in the electronic typewriter proposed by the applicant of the present application, the erase ribbon winding mechanism is configured to step-feed the erase ribbon after the erase operation. The chit wheel is attached to the holder member, the ratchet pawl is attached to the carriage side, and the ratchet ratchet pawl and the ratchet pawl are required to have a delicate positional relationship that enables engagement. Fine adjustment of the mounting position is required when mounting the pawls, and it takes time for the mounting work, and the amount of play in the pivotal support mechanism that pivots the holder member up and down supports the ratchet pawl and ratchet pawl. There is a problem in that the engagement relationship is not stable and a mistake in winding the erasing ribbon may occur.

It is an object of the present invention to provide a printing apparatus which can surely perform an erasing ribbon winding operation associated with an erasing operation.

[0007]

According to a first aspect of the present invention, there is provided a printing apparatus in which a type wheel and a printing hammer are provided in a carriage body which is driven to reciprocate in a horizontal direction along a platen, and a printing ribbon is provided in the carriage body. The holder member for mounting the erasing ribbon is mounted so that the rear end side can be switched between the erasing position where the rear end is lifted up by a predetermined height and the printing position where the rear end side is not lifted up, and the holder member and the carriage body. In a printing apparatus having an erasing ribbon winding mechanism that feeds the erasing ribbon in steps when the position of the holder member is switched, the erasing ribbon winding mechanism engages the ratchet wheel connected to the erasing ribbon spool and the ratchet wheel. The ratchet pawl member is provided, and the ratchet pawl member is always engaged with the ratchet wheel. It is provided with a spring member for biasing to.

[0008]

In the printing apparatus according to the first aspect, during the erasing operation, the holder member on which the printing ribbon and the erasing ribbon are mounted is switched to the erasing position where the rear end side is lifted up by a predetermined height, and then lifted. The position is switched to the print position that does not go up. Then, when the position of the holder member is switched, the erasing ribbon is step-fed by the erasing ribbon winding mechanism. That is, since the ratchet pawl of the ratchet pawl member is biased by the spring member so as to always engage with the ratchet wheel connected to the erasing ribbon spool, the ratchet pawl and the ratchet wheel are always in a predetermined engagement positional relationship. The ratchet wheel is reliably rotated by the ratchet pawl when the position of the holder member is switched, and the erase ribbon is wound.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, the present invention is applied to an electronic typewriter in which one DC motor performs a printing operation, a printing ribbon winding operation associated therewith, an erasing operation and an erasing ribbon winding operation associated therewith. It is a thing. Figure 1
As shown in FIGS. 2 and 10, side wall plates (machine frames) 2 are provided at both left and right inside the casing of the typewriter 1, and the platen 3 arranged between the pair of side wall plates 2 is ,
The platen shaft 4 is rotatably supported by both side wall plates 2 in the vicinity of both ends thereof, and is rotated by a line feed motor and a platen drive mechanism (not shown) via a driven gear (not shown) fixed to the left end of the platen shaft 4. Driven.

Between the pair of side wall plates 2, a guide shaft 5 and a guide member 6 having a substantially U-shape in side view are further arranged in parallel with the platen 3. Next, these guide shaft 5 and guide member The carriage 7, which is supported by the carriage 6 so as to be movable in the left-right direction, will be described with reference to FIGS. 1, 5, 7, and 10. Between the guide shaft 5 and the guide member 6, a pair of plate-like and substantially rectangular metal main frames 8a, 8b are arranged in the front-rear direction with a predetermined distance in the left-right direction. The frames 8a and 8b are the first of support members 9 supported by the guide shaft 5 so as to be movable in the left-right direction and rotatable.
Pins 12 are inserted from the outside to the upper ends of the support parts 10 and the second support parts 11 and the upper ends of the support parts 10 and 11 inserted as spacers between the main frames 8a and 8b.
・ They are fixed at 13, respectively. Therefore, the carriage main body 14 is constituted by the main frames 8a and 8b, the support member 9, and the like.

Next, the printing mechanism 15 will be described.
A DC motor 16 is supported on the right main frame 8a in a state in which the DC motor 16 is prevented from rotating, and a drive shaft 17 of the motor 16 extends leftward by inserting both main frames 8a and 8b. 17 from the motor 16 side,
A printing cam 18 which is located inside both main frames 8a and 8b and which has a generally side-viewed shape in a side view, an encoder disk 19 having a plurality of slits formed on the outer peripheral portion thereof, and a ribbon supply for feeding the printing ribbon PR stepwise. The cam 22 and the raising cam 21 for raising and driving the holder member 32 to the erasing position are fixed to each other. The ribbon supply cam 22 and the lifting cam 21 are integrally formed. Also, FIG.
The dotted line indicates the printing start position of the printing cam 18 and the dashed line indicates the origin setting position.

A pair of left and right rotating levers 23 having a substantially doglegged shape in a side view are provided at the upper ends of the rear ends of the main frames 8a and 8b.
And a lower end of the link 24 are rotatably supported by a pin 25 and a screw 26, respectively. On the other hand, as shown in FIGS. 1 to 3, the print hammer 27 is disposed in the front-rear direction so as to face the platen 3 and holds the metal hammer body 35 and a substantially first half of the hammer body 35. The holder 36 is made of synthetic resin.

The print hammer 27 is rotatably supported by a pin 38 at the front end portion of the holder 36, that is, at the front end portion of the holder 36, and at the center portion in the front-rear direction, that is, the holder 36. A pin 37 is pivotally supported on the upper end of the rotating lever 23 at the rear end thereof. That is, the link 24 and the upper half of the rotary lever 23 and the pins 25, 37,
38 and the screw 26 constitute a parallel link mechanism, and the print hammer 27 is attached to both main frames 8a and 8b via the parallel link mechanism.
Are capable of reciprocating back and forth in a substantially straight line.

The metal pin 37 and the hammer body 35 are also provided.
Since they do not come into direct contact with, it is possible to reliably prevent the generation of these collision sounds during the printing operation and the erasing operation described later. A cam follower 2 is provided at the front end of the rotating lever 23.
8 is rotatably pivoted, and the tension spring 2 is attached to the upper end of the rotary lever 23 and the lower end of the link 24 so that the cam follower 28 always contacts the cam surface of the printing cam 18.
Nine are stretched.

Here, a pivot structure for pivotally supporting the pivot lever 23 on both main frames 8a and 8b through the pin 25 will be described with reference to FIGS. The collar pin 25 has a collar portion 25 provided near the left end.
a, a screw portion 25b provided at the left end portion thereof, and a collar portion 2
5a to the right of the pin portion 25c, the screw portion 25b
Through the pin hole of the main frame 8b, and
In the state where c is inserted into the pin hole of the main frame 8a, the main frame 8b has a collar portion 25a and a screw portion 25.
It is screwed by a nut 39 screwed to b.

Therefore, since the main frame 8b and the axial direction of the flanged pin 25 are surely orthogonal to each other, the pin holes of both the main frames 8a and 8b are exactly opposed to each other through the flanged pin 25, The main frames 8a and 8b can be made to face each other with high precision and with high accuracy by the flanged pin 25. Further, the pair of turning levers 23 are provided with spacers 40 provided at the left and right ends of the pivoting support portions 40a, respectively.
It is rotatably supported by the flanged pin 25 via.
The left and right pivotal support portions 40a of the spacer 40 are fixed to the pair of turning levers 23 by caulking. Further, a plate washer 45 is provided on the flanged pin 25 between the main frame 8a and the right rotation lever 23,
Due to the elastic deformation of the dish washer 45, the play between the turning lever 23 and the main frames 8a and 8b in the left-right direction is absorbed by the dish washer 45. Therefore,
The reaction force of the striking force of the printing hammer 27 during the printing operation is applied to both the main frames 8a and 8a through the flanged pin 25.
Since it acts evenly on b and the reaction force is reliably received by the guide member 6 via the contact member 44 described later, the impact force (impact force) of the print hammer 27 can be reliably obtained.

On the other hand, the link 24 via the stepped screw 26
A pivot structure for rotatably pivoting the lower end of the main frame 8a and 8b to both main frames 8a and 8b will be described with reference to FIGS. 2 and 4. The main frame 8b has a stepped screw 26 through which the main frame 8a is inserted. Is screwed by a nut 46, and the lower end of the link 24 is rotatably supported by the stepped screw 26. On the other hand, a protective member 47 made of synthetic resin and having a substantially U-shape in plan view extending from the middle portion in the height direction to the lower end portion is disposed so as to cover substantially the periphery of the link 24. Bifurcated pivot support 47 formed at the lower end
a is externally fitted to the stepped screw 26 at the left and right sides of the lower end of the link 24. Further, the spring member 48 wound around the right end portion of the stepped screw 26 extends substantially upward and its upper end portion is engaged with the upper end portion of the link 24 from the left.

Therefore, since the link 24 and the print hammer 27 connected to the link 24 are constantly urged to the right by the spring force of the spring member 48, the print hammer 27 is rotated with respect to the parallel link mechanism. The play, that is, the play in the connecting portion with the moving lever 23, the connecting portion with the printing hammer 27 and the link 24, and the connecting portion with the link 24 and both the main frames 8a and 8b is always provided on the predetermined side. It is possible to reduce the hitting sound of the printing hammer 27 during the erasing operation, particularly the hitting sound of high frequency.

Reference numeral 30 is a wheel drive motor 49.
(See FIG. 13) and a daisy wheel rotatably driven by a wheel driving mechanism (not shown). Reference numeral 31 is a ribbon cassette storing the print ribbon PR, and reference numeral 32 is a ribbon cassette.
Is a holder member on which a ribbon cassette 31 is placed and which can be vertically swung via a support shaft 34 to a holder bracket 33 pivotally supported by a guide shaft 5 so as to be integrally movable with a carriage body 14. . The carriage 7 is reciprocated in the left-right direction along the platen 3 via a drive wire by a carriage drive motor and a drive mechanism (not shown).

As shown in FIG. 7, the curved cam surface on the outer side of the printing cam 18 has a large radius expansion rate in a substantially first half portion in a sliding range in which the cam follower 28 slides. The radius enlargement ratio is very small in the approximately latter half portion including the striking portion where the cam follower 28 slides when 27 strikes the platen 3. Moreover, the printing cam 18 is configured so that the printing hammer 27 can be pressed against the platen 3 even after the printing hammer 27 is hit.
The curved cam extends from the sliding range by a predetermined length.

Therefore, when the motor 16 is rotated at a high speed by a predetermined angle in the print direction P from the print start position in FIG.
Since the cam follower 28 rises along the cam surface of the printing cam 18, the rotation lever 23 rotates in the counterclockwise direction, and the print hammer 27 moves the platen 3 through the type of the daisy wheel 30 and the print ribbon PR. Hit and press.

Here, adjustment plates 41 extending in the front-rear direction are provided outside the upper ends of the main frames 8a and 8b, respectively, and the front ends of the adjustment plates 41 are respectively attached to the main frames 8a and 8b. The support shaft 42 inserted through the formed oval hole 8c is fixed. On the other hand, as shown in FIGS. 7 and 11, a contact portion 44b is provided at the front end of a contact member 44 whose rear end is rotatably supported by the support shaft 42. A bearing 54, which movably contacts the rear end surface of the guide member 6, is rotatably supported by a pivot shaft 55 on the portion 44b. Moreover, as shown in FIGS. 5 and 10, the contact member 44 is urged to rotate in the counterclockwise direction in FIG. 7 by the winding spring 56 mounted on the support shaft 42. The guide portion 44a formed in a forward projecting shape at the front end portion of 44b is always in contact with the lower side of the guide member 6, that is, the bearing 54 is always in contact with the rear end surface of the guide member 6, so that the carriage 7 smoothly moves to the left and right. It can be moved back and forth.

By the way, the reaction force of the striking and pressing of the printing hammer 27 during the printing operation is received by the guide member 6 via the printing mechanism 15 and the contact member 44, so that the strength of the guide member 6 is increased. 1, Figure 5, Figure 7, Figure 1
As shown in FIG. 0, a reinforcing member 57 made of a plate material is disposed inside the guide member 6 over substantially the entire length thereof, and the reinforcing member 57 is attached to the guide member 6 by spot welding at a plurality of locations. Further, as shown in FIG. 10, in the bifurcated mounting portions 6a at the left and right ends of the guide member 6,
It is fixed to the side wall plate 2 by hot crimping.

Next, a cam mechanism 50 for raising the holder member 32 from the printing position to the erasing position so that the erasing ribbon CR faces the printing hammer 27 at the time of erasing characters will be described with reference to FIGS. The rising cam 21 includes:
A reference cam 21a having an equal radius from the center of the cam 21
A first inclined cam surface 21b continuously extending in the radial expansion direction from the reference cam 21a, and the first inclined cam surface 21.
A second inclined cam surface 21c that is continuous with the outer peripheral cam surface 21d in the middle of b is formed, and an outer peripheral wall 21e extends from the right end portion of the outer peripheral cam surface 21d in the radial expansion direction. A rib 21f protruding leftward is formed on the portion.

A part of the outer peripheral wall 21e is provided on the outer peripheral wall 21e.
e and the leftward protruding portion 21p of the left end surface of the first inclined cam surface 21b
In the left-right direction, that is, about 1/3 of the total movement amount (about 5 mm) of the first driven pin 52 moving in the left-right direction.
A shallow bottom surface 21h is formed from 1e, and an inclined surface 21i is formed from the shallow bottom surface 21h to the left end surface 21g of the cam 21. In addition, the depth of the inner peripheral side of the inclined surface 21i is about 1 / of the total movement amount with respect to the depth of the outer peripheral side.
It is 3 shallower. Further, the advance side portion and the retard side portion of the shallow bottom surface 21h are respectively connected to the outer peripheral wall 21e by inclined surfaces.

Here, in the guide wall 21j between the second inclined cam surface 21c and the outer peripheral cam surface 21d, as shown in FIGS. 8 and 9, two arc-shaped recesses 21m are formed. At the same time, an arcuate recess 21n is similarly formed on the left end surface 21g corresponding to the left end of the first inclined cam surface 21b. Further, the rib 21f includes a second inclined cam surface 21c.
Pin guide cam 2 that protrudes leftward from the vicinity of the terminal end of the rib in the counterclockwise direction over about 1/4 of the outer peripheral distance of the rib 21f.
1k is formed, and a second driven pin 58 described later can be engaged with the pin guide cam 21k.

Next, the support member 51 for supporting the first driven pin 52 and the second driven pin 58 which come into contact with the ascending cam 21 from the left will be described with reference to FIGS. 6, 8 and 16. The support member 51 includes a mounting wall 51a mounted at one location (corresponding to a pin mounting portion) of the side wall 32a at the left end of the holder member 32, and a pivot wall provided in parallel to the right side of the mounting wall 51a. 51b and a support wall 51c connected to the mounting wall 51a and the pivotal support wall 51b, and a rotary member 71 made of synthetic resin disposed inside the attachment wall 51a and the pivotal support wall 51b. Is a pivot pin 7 in the left-right direction supported by these both walls 51a and 51b.
It is rotatably pivoted on 2.

The rotating member 71 has a first driven pin 52.
Is always elastically biased and held to the right by a compression spring (not shown), and a pin holding member 73 having a second driven pin 58 is formed. On the other hand, the tension spring 74 is stretched over the lower end portion of the rotating member 71 and the pivot wall 51b, and the rotating member 71 is rotated so that the first driven pin 52 always follows the ascending cam 21. It is elastically biased in the clockwise direction. Further, a receiving portion 73a that receives the support wall 51c from below is formed at the upper end portion of the pin holding member 73, and a rubber cushion member 59 is attached to the upper side of the receiving portion 73a, and the pin holding member 73 is formed. Is elastically abutted against the support wall 51c through the cushion member 59.

Therefore, the first driven pin 52 is usually
As shown in FIG. 7, the holder member 32 and the auxiliary frame 33
With the spring force of the tension spring 97 (see FIG. 16) stretched over and the own weight of the holder member 32, the pin tip end of the first driven pin 52 is rotated from above in contact with the reference cam 21a. The holder member 32 is supported at the printing position (reference swing position) shown in FIGS. 1, 16 and 17 via the moving member 71 and the supporting member 51, and the left end face 21g is elastically biased from the left side. There is. That is, the vertical rotation amount of the holder member 32 is determined by the vertical movement amount of the first driven pin 52. Here, the printing cam 1 at the start of printing
8 shows the positional relationship among the lifting cam 21, the lifting cam 21, the first driven pin 52, and the cam follower 28. However, the position of the first driven pin 52 at the start of printing is P0 (see FIG. 15).

Therefore, the ascending cam 21 is moved in the printing direction P by the motor 16 from the phase angle at the start of printing shown in FIGS.
When the first driven pin 52 is moved upward by the first inclined cam surface 21b when rotated by a predetermined angle in the opposite direction (referred to as the anti-printing direction), the holder member 32 is also moved upward depending on the upward moving distance. Since the first driven pin 52 reaches the outer peripheral cam surface 21d via the second inclined cam surface 21c when the cam 21 for rotation is rotated in the printing direction P after rotating.
The holder member 32 is rotated further upward, and
The erase position is switched to. At this time, the erasing ribbon CR is at a position facing the print hammer 27.

By the way, when the first driven pin 52 moves on the first inclined cam surface 21b, since the pin tip of the first driven pin 52 is in contact with the left end surface 21g, the elastic biasing force is large. In this state, when the first driven pin 52 moves to the second inclined cam surface 21c, the pin 52
The pin tip of will collide strongly with the guide wall 21j,
There is a clicking sound of "click". However, as described above, since the guide wall 21j is formed with the two recesses 21m, it is difficult for the vibration at the time of collision to propagate to the entire cam 21,
Particularly high vibration frequency can be cut, and collision noise can be reduced.

Next, a print ribbon winding mechanism 60 for winding a predetermined amount of the print ribbon PR on the take-up spool for each printing operation will be described with reference to FIGS. 6 and 10. At the lower left end of the holder member 32, a ratchet 61 having a plurality of teeth is rotatably supported by a pin 62.
The third swinging member 63, which is rotatably supported by the holder and is provided with the feed claw 63a, is connected to the second swinging member 64 pivotally attached to the holder member 32 via a connecting pin 65. The 2 rocking member 64 is elastically biased in the counterclockwise direction in FIG. 12 by the tension spring 66. The take-up spool 67 is fixed to the pin 62.

On the other hand, the ribbon-feeding cam 2 having the above-mentioned approximately tomo shape.
At the position 2, the lower end portion of the first swing member 69 is rotatably supported by the pivot pin 68 fixed to the main frame 8b, and the upper end portion of the first swing member 69 is the second swing member. 64
Is in contact with the vicinity of the base end from the front. Furthermore, this first
The ribbon supply cam 22 is located in a substantially circular hole 69a formed in the swinging member 69, and the first swinging member 69 is always contacted with a part of the ribbon supply cam 22. The 1 rocking member 69 is elastically biased upward with respect to the paper surface in FIG. 6 by a winding spring 70 mounted on the pivot pin 68.

Therefore, the ribbon supply cam 22 is set to the motor 1
When rotated in the printing direction P by 6, the first swinging member 6
9 swings downward with respect to the paper surface in FIG. 6 due to the cam shape of the ribbon supply cam 22, so that the second swinging member 64 is rotated clockwise in FIG. 12 and the third swinging member is rotated. 63
Rotates counterclockwise to rotate the ratchet 61 by one tooth by the feed claw 63a, and the print ribbon PR is stepwise fed by a predetermined amount by the take-up spool 67 immediately before printing.

Next, at the time of erasing, an erasing ribbon winding mechanism 75 for winding a predetermined amount of the erasing ribbon CR on the winding spool.
This will be described with reference to FIGS. 5, 10, 13, and 17. On the side wall 32a at the rear end of the holder member 32,
A supply spool 76 for the erasing ribbon CR is rotatably pivotally mounted, and a take-up spool 7 for the erasing ribbon CR is provided at the right end portion thereof.
7 is rotatably pivoted. This take-up spool 7
7 is provided with a ratchet wheel 78 having a plurality of teeth. Below the ratchet wheel 78, a ratchet pawl member 79 is rotatably supported by a pin 86 on a pivot support plate 85 provided upright from the auxiliary frame 33. Is pivotally supported, and a ratchet pawl 79a for rotating the ratchet wheel 78 by one tooth is extended upward so as to engage with the ratchet wheel 78 from the front side. Further, the ratchet pawl member 79 is elastically biased in the counterclockwise direction in FIG. 17 by a coil spring (corresponding to a spring member) 87 that is mounted on the pin 86, and the ratchet pawl 79a is rotated by the ratchet wheel 78.
Always engaged with the teeth of.

That is, as described for the cam mechanism 50, when the phase angle of the ascending cam 21 at the start of printing is 0 °,
As shown in FIGS. 15 to 19, first, when the ascending cam 21 is rotated from the phase angle of 0 ° (see FIG. 16) in the anti-printing direction by about 55 ° (hereinafter referred to as the phase angle of −55 °), The driven pin 52 has a phase angle of about −43 ° from a phase angle of about −5 °.
After moving upward along the first inclined cam surface 21b, it is located on the second inclined cam surface 21c. At this time, the first driven pin 52 is about 2 mm away from the position of the reference cam 21a.
It is a raised position. In addition, in FIG. 17 and FIG.
The ascending cam 21 is shown by a solid line, the ribbon supply cam 22 is shown by a one-dot chain line, and the first swinging member 69 is shown by a two-dot chain line.

Then, the raising cam 21 is about
When rotated in the printing direction P at a high speed from 55 ° to 90 °, the first driven pin 52 moves on the second inclined cam surface 21c and then reaches the outer peripheral cam surface 21d (see FIG. 19). That is, at this time, the holder member 32 is switched to the erasing position where the erasing ribbon CR faces the print hammer 27. At this time, as described above, the second driven pin 58 engages with the pin guide cam 21k from the outside, so that the first driven pin 52 is slightly separated from the outer peripheral cam surface 21d, and
The pin tip of the driven pin 52 surely contacts the outer peripheral wall 21e.

Here, at the position P1 during the movement of the first driven pin 52, the ratchet pawl member 79 and the ratchet wheel 78 start to engage with each other, and as the holder member 32 rises, the ratchet wheel at the subsequent position P2. 78 is surely rotated by one tooth. Therefore, the erasing ribbon CR is wound around the winding spool 77 by a predetermined amount and fed stepwise. At this time, the first driven pin 52 is
The position is about 5.7 mm higher than the reference cam 21a.

By the way, as described above, when the motor 16 rotates in the printing direction P at a high speed from about -55 ° to 90 ° in order to obtain a predetermined impact force by the printing hammer 27 at the time of erasing. , The first driven pin 52 is about 5.7.
Soar to mm. Therefore, when the holder member 32 also rapidly rises at the same time, the inertia of the holder member 32 tends to cause the holder member 32 to pivot largely upward beyond the erasing position about the support shaft 34. Therefore, as shown in FIGS. 16 and 18, on the side wall 32a of the holder member 32, a rocking restricting plate (corresponding to a locking arm member) 88 made of a curved plate material is provided, and its front end portion is guided by the guide member 6. It is fixed at its rear end so that it is located underneath. Therefore, the holder member 32 is
At the print position shown in FIG. 6, the rocking restricting plate 88 is located below the guide member 6, but at the erase position shown in FIG. 18, the rocking restricting plate 88 is below the guide member 32. Since they abut, the upward rotation of the holder member 32 beyond the erasing position can be reliably regulated. The rotation restricting mechanism is composed of the guide member 6 and the swing restricting plate 88.

Then, the ascending cam 21 is at 90 degrees.
After the erasing operation is performed by rotating in the printing direction P from 0 ° to about 270 °, when the raising cam 21 rotates to −90 ° in the anti-printing direction, the first driven pin 52 is moved by the own weight of the holder member 32. As the outer peripheral cam surface 21d moves to the reference cam 21a via the shallow bottom surface 21h and the inclined surface 21i, the holder member 32 descends to the print position as shown in FIG. At this time, the ratchet wheel 78
A ratchet pawl 79 is provided by a reverse rotation preventing pawl 89 that engages with the
a engages the next tooth on the ratchet wheel 78. After that, the motor 16 rotates to a phase angle of 0 °.

Here, as shown by the one-dot chain line in FIG.
When the holder member 32 rotates downward from the erasing position to the printing position and the ascending cam 21 rotates at a phase angle of 0 °, the first driven pin 52 moves from +3 mm to − from the position of the reference cam 21a. It moves to the left by up to 2mm, that is, about 5mm corresponding to the total movement. Therefore, the total amount of leftward movement of the first driven pin 52 is set to about −60 of the ascending cam 21.
Approximately 1/3 of the total movement amount due to the movement to the shallow bottom surface 21h in the rotation from 90 ° to −90 °, and the own weight of the holder member 32 at −90 ° and the holder member 32 are elastically biased downward. About 1/3 of the total movement amount due to the movement of the tension spring 97 (shown in FIG. 16) to the left end face 21g through the inclined surface 21i and about the total movement amount due to the rotation from -90 ° to 0 °. Since it is divided into 1/3, the first
The leftward movement of the driven pin 52 becomes stepwise and smooth, and the holder member 32 can surely descend to the printing position after the erasing operation.

Next, the release mechanism 80 for rotating the carriage body 14 to the release position in order to replace the daisy wheel 30 will be described with reference to FIGS.
The rear end of the release lever 82 pivotally supported on the main frame 8a is pivotally supported on the main frame 8a by a pin 83.
4, the rear end of the connecting member 84 is in contact with the front end of the rotating member 81 fixed to the support shaft 42 from below. Therefore, when the release lever 82 is operated to rotate from the print position shown by the solid line to the release position shown by the chain double-dashed line in FIG. 14, the connecting member 84 is rotated in the clockwise direction. 81 is rotated counterclockwise.

As a result, the contact member 44, which is integrally connected to the rotating member 81 via the support shaft 42, is rotated in the counterclockwise direction to release the engagement with the guide member 6 and the carriage main body. 14 is rotated around the guide shaft 5 to the release position shown in FIG. At this time, as shown in FIGS. 8 and 20, since the rotating member 71 is rotatable with respect to the support member 51, the first driven pin 52 moves the reference cam 21a as the ascending cam 21 descends. Since the carriage main body 14 is lowered while being in contact with the carriage body 14, the carriage body 14 is rotated to a release position where the daisy wheel 30 can be attached and detached, a sufficient attachment / detachment space is secured, and the daisy wheel 30 can be attached and detached.

By the way, after the daisy wheel 30 is replaced, the release lever 82 is operated to the platen 3 side to return and rotate the carriage body 14 to the set position, but when the operation of the release lever 82 is insufficient, FIG. As shown, one contact portion 44b and one bearing 54 contact the guide member 6 in a stable state, that is, the guide portion 44a does not contact the lower side of the guide member 6, and the bearing 54 guides There may be a so-called half-lock state in which the rear end surface of the member 6 is not normally contacted. 10 to 12 in a predetermined position outside the printing area of the carriage 7 at a position near the left end of the rear end of the guide member 6.
As shown in FIG. 6, a substantially V-shaped notch 6c is formed on the lower wall portion 6b from a position slightly higher than the middle portion of the rear end in the height direction.
Are formed.

That is, after the replacement of the daisy wheel 30, even if the contact member 44 is in the half-locked state, the carriage 7 is moved to the left until the initial setting position where the carriage 7 contacts the left side wall plate 2 for initial setting. The bearing 54 passes through the notch 6c when moving to. At this time, the bearing 54 does not contact the guide member 6, and the contact member 4
Since 4 is urged to rotate counterclockwise in FIG. 11 by a winding spring 56 mounted on the support shaft 42, the contact member 44 has a normal force indicated by a two-dot chain line by the spring force of the winding spring 56. The rotation is returned to the contact position of and the half lock state is automatically released.

Next, referring to FIG. 13, the printing hammer 27
The position adjustment for matching the center position of the print type with the center position of the type will be described. The wheel drive motor 49 including a stepping motor is held by a motor holder 90, and the motor holder 90 is provided with a pair of arcuate pivot holes 90a. It is attached to a wheel holding member (not shown) with a pair of screws 91. Then, the drive gear 92 fixed to the drive shaft of the wheel drive motor 49 meshes with the wheel drive gear 93 rotatably supported by the wheel holding member, and the wheel drive gear 93 rotates the daisy wheel 30. There is.

Therefore, with the wheel drive motor 49 excited in a predetermined excitation phase, both screws 91 are loosened, and the motor holder 90 is rotated clockwise or counterclockwise in FIG. 13 via the pivot hole 90a. When the wheel drive gear 93, that is, the daisy wheel 30 is rotated in the counterclockwise or clockwise direction via the drive gear 92, the center position of the type is easily located at the center position of the print hammer 27. Can be matched.

By the way, the typewriter 1 is tightly packed with a predetermined packing material and shipped from the factory by a truck or the like. However, the typewriter 1 is transported in various ways from the factory to the user's hand. The package may drop. In this case, the direction of the impact that acts on the packaged product depends on the state of drop. Therefore, among the plurality of impact directions that act on the typewriter 1, particularly the carriage 7, impacts in the left and right directions of the carriage 7 are considered.
Usually, since the movement in the left-right direction is fixed by a predetermined fixing metal fitting, there is no problem.

However, as shown in FIG.
With respect to the rotation about the guide shaft 5 in the counterclockwise direction, the carriage 7 moves the contact member 4
Since it is received by the guide member 6 via the shaft 4 and the support shaft 42, it is strong against impact. On the other hand, in the case of clockwise rotation, the carriage 7 presses a wheel drive mechanism (not shown), a paper meter, or the like, which is arranged immediately behind the carriage 7, and may deform them. . However, as shown in FIGS. 2 and 7, a large washer 94 is screwed to the front end of the main frame 8a, and the gap between the washer 94 and the guide member 6 is very small. Therefore, when the washer 94 and the guide member 6 are in contact with each other, the rotation of the carriage 7 in the clockwise direction at the time of impact is surely restricted.

As described above, the ratchet wheel 78 connected to the erasing ribbon take-up spool 77 is pivotally attached to the holder member 32, the ratchet pawl member 79 is pivotally attached to the auxiliary frame 33 of the carriage 7, and the ratchet pawl is also provided. Since 79a is elastically biased by the winding spring 87 so as to be constantly engaged with the ratchet wheel 78, regardless of the amount of play in the pivot mechanism that pivotally supports the holder member 32 in the vertical direction, these ratchets are not supported. The claws 79a and the ratchet wheel 78 are always kept in engagement with each other, and the ratchet wheel 78 is retained when the position of the holder member 32 is changed.
Is reliably rotated by the ratchet pawl 79a, and the erasing ribbon CR can be reliably wound. Further, since the ratchet pawl 79a is elastically biased so as to be constantly engaged with the ratchet wheel 78, the mounting position adjustment at the time of mounting the ratchet pawl member 79 can be eliminated and the mounting work can be simplified.

The ratchet wheel 78 and the ratchet pawl member 79 may be partially changed, and the ratchet wheel 78 may be rotated by one tooth when the holder member 32 is lowered. The shape of the ratchet pawl member 79 is not limited to that of this embodiment, and may be any shape. The erasing ribbon winding mechanism may have various structures including a ratchet wheel and a ratchet pawl member.

[0052]

According to the printing apparatus of the first aspect, as described in the section [Operation], the ratchet pawl of the ratchet pawl member provided in the erasing ribbon winding mechanism is connected to the erasing ribbon spool. Since it is biased by the spring member so as to always engage with the ratchet wheel, the ratchet pawl and the ratchet wheel are not affected by the amount of play in the pivotal support mechanism that pivotally supports the holder member in the vertical direction. The predetermined engagement relationship is maintained at all times, and the ratchet wheel is reliably rotated by the ratchet pawls when the position of the holder member is switched, so that the erase ribbon can be reliably wound. Further, since the ratchet pawl is elastically biased so as to always engage with the ratchet wheel, adjustment of the mounting position at the time of mounting the ratchet pawl member can be omitted, and the mounting work can be simplified.

[Brief description of drawings]

FIG. 1 is a side view of an internal mechanism of an electronic typewriter.

FIG. 2 is a side view of a carriage.

FIG. 3 is a sectional view taken along line CC of FIG.

FIG. 4 is a sectional view taken along the line DD of FIG.

5 is a view on arrow A in FIG. 1. FIG.

FIG. 6 is a partial front view of the internal mechanism of the electronic typewriter.

FIG. 7 is a side view of a main frame and a guide member.

FIG. 8 is a perspective view of a lifting cam and a supporting member.

9 is a sectional view taken along line EE of FIG.

10 is a view on arrow B in FIG. 1. FIG.

11 is a sectional view taken along line FF of FIG.

12 is a view on arrow G in FIG.

FIG. 13 is a rear view of the main part of the internal mechanism.

FIG. 14 is a side view of the internal mechanism for explaining the release mechanism.

FIG. 15 is a diagram showing a motion curve and a lateral movement amount of a first driven pin.

16 is a view corresponding to FIG. 1 showing a schematic internal mechanism in a printing state.

FIG. 17 is a side view of the main parts of the internal mechanism at the print start position.

18 is a view corresponding to FIG. 1 showing a schematic internal mechanism in an erased state.

19 is a view corresponding to FIG. 17 when the holder member is switched to the erasing position.

20 is a view corresponding to FIG. 1 in a released state of the carriage.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic typewriter 3 Platen 5 Guide shaft 6 Guide member 7 Carriage 14 Carriage body 21 Lifting cam 27 Printing hammer 30 Dizzy wheel 32 Holder member 52 First driven pin 75 Erasing ribbon winding mechanism 77 Winding spool 78 Ratchet wheel 79 Ratchet Claw member 79a Ratchet claw 87 Wound spring PR Print ribbon CR Erase ribbon

Claims (1)

[Claims] 1. A carriage body, which is reciprocally driven in the left-right direction along a platen, is provided with a type wheel and a print hammer, and a holder member for mounting a print ribbon and an erasing ribbon is provided on the carriage body. The end side is mounted so that the position can be switched by rotating it between the erasing position where it is lifted up by a predetermined height and the printing position where it is not lifted up, and the erasing ribbon is fed stepwise between the holder member and the carriage body when switching the position of the holder member. In the printing device provided with the erasing ribbon winding mechanism, the erasing ribbon winding mechanism includes a ratchet wheel connected to the erasing ribbon spool and a ratchet pawl member engaging with the ratchet wheel. A spring member that biases the ratchet pawl so that the ratchet pawl always engages the ratchet wheel. Printing apparatus, characterized in that the.