JPH05185706A - Printing device - Google Patents

Abstract

PURPOSE:To provide a printing device, with which a holding member at erasing position can surely be lowered to printing position. CONSTITUTION:At the outer peripheral part of a lifting cam 21, groove 21a, which is isosemidiametrical about its center and at some part of which a shallow bottom part 21b is provided. The inside of the groove 21a serves as a second cam 21d. Some part of a left edge face 21e adjacent to the shallow bottom part 21b is notched so as to form a slant surface 21f, which slants from the neighborhood of a first cam 21c to the shallow bottom part 21b. At about one third part of the slant surface 21b, which spreads counterclockwise over the second cam 21d, a second slant cam 21h is formed. The radius of the outside of the second slant cam 21h is equal to that of the second cam 21d so as to form a connecting part 21k, which connects the second cam 21d with the shallow bottom part 21b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a type wheel type printing apparatus, and more particularly, at the time of erasing characters, a holder member having a printing ribbon and an erasing ribbon mounted thereon is swung upward from a printing position to erase the characters, and at the end of the erasing operation. The present invention relates to a device that swings downward.

[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 at a printing position where the printing ribbon faces the printing hammer during printing and an 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 invention filed Japanese Patent Application No. 3-129.
In the specification and the drawings attached to the application No. 49, 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. In this way, an electronic typewriter that can reduce the manufacturing cost and can make the carriage compact is proposed.

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 for holding the holder member at the printing position, a peripheral cam for holding the erasing position, and inclined first and second inclined cams connecting the reference cam and the peripheral cam surface are formed on the ascending cam. Further, a driven pin that slides on the lifting cam is attached to the holder member.

Then, 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, and the printing hammer is operated to print through the printing cam, while the motor is driven. The driven pin is configured to perform the erasing operation in a state where the driven pin is slid on the outer peripheral cam via the first and second inclined cams by the reverse rotation and the forward rotation of a predetermined angle to hold the holder member at the erasing position. ..

[0007]

As described above, in the electronic typewriter proposed by the present applicant in the previous application, the driven pin is rotated in the second tilt by the reverse rotation of the motor after the erasing operation is completed. Move to the reference cam while sliding on the cam. With the movement of the driven pin, the holder member also gradually descends from the erasing position toward the printing position.

In the electronic typewriter, the print ribbon winding mechanism includes a first swinging member and a ribbon supply cam that is integrally formed with the lifting cam and swings the first swinging member and a holder. A second swing member provided on the member, and when the holder member is in the printing position, the first
The ink ribbon is wound by swinging the swing member to engage and swing the second swing member.

The first swinging member swings even during the erasing operation because the raising cam and the ribbon feeding cam are integrally formed. Therefore, as described above, after the erasing operation is completed, the second oscillating member may get on the first oscillating member that oscillates when the holder member gradually descends from the erasing position toward the printing position. The second on the first rocking member
If the swinging member gets on the holder member, the holder member does not descend to the printing position, and the next printing operation cannot be performed.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a printing apparatus capable of reliably lowering the holder member at the erasing position to the printing position.

[0011]

A printing apparatus according to the present invention is provided with a print wheel and a print hammer in a carriage body which is driven to reciprocate left and right along a platen, and a print ribbon and an eraser are provided in the carriage body. A holder member for mounting the ribbon is mounted so that the rear end side can be switched in position by rotating between an erasing position where the rear end is lifted up by a predetermined height and a printing position where the rear end side is not lifted up, and a cam driven by the holder member. And a first cam follower that slides on a peripheral surface of the first cam so that the holder member is held at the printing position.
The cam, the second cam that holds the holder member at the erasing position by sliding the cam follower on its peripheral surface, and the cam follower from the first cam to the first cam by rotating the motor at least in the forward direction. A cam body provided with a third cam for guiding to the two cams, the cam body being rotationally driven by a motor, is provided in the carriage body, and the cam follower is moved from the second cam by rotating the motor at least in the reverse direction. When moving to the first cam,
The cam body is provided with a fourth cam that guides the second follower from the second cam to the first cam without engaging the cam follower with the third cam.

[0012]

In the printing apparatus according to the present invention, during the printing operation, the cam follower slides on the peripheral surface of the first cam and the holder member is held at the printing position. Further, during the erasing operation, the cam follower is guided from the first cam to the second cam by the third cam by the rotation of the motor in at least the forward direction. After the erasing operation is completed, the cam follower moves from the second cam to the fourth cam without engaging with the third cam by the rotation of the motor in the reverse direction, and the fourth cam guides the cam to the first cam. To be done.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. In this 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.

As shown in FIGS. 1 and 2, the typewriter 1
Side wall plates (machine frame) on both left and right sides inside the casing of
2 is provided, and the platen 3 disposed between the pair of side wall plates 2 is rotatably instructed to both side wall plates 2 near both ends of the platen shaft 4, and the platen shaft 4
It is rotationally driven by a platen drive motor and a platen drive mechanism (not shown) via a driven gear (not shown) fixed to the left end of the.

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, the guide shaft 5 and the guides are arranged. The carriage 7 supported by the member 6 so as to be movable in the left-right direction will be described with reference to FIGS.

Between the guide shaft 5 and the guide member 6, a pair of plate-like and substantially rectangular main frames 8 are arranged in the front-rear direction with a predetermined distance in the left-right direction. Is an upper end portion of the first support portion 10 and the second support portion 11 of the support member 9 supported by the guide shaft 5 so as to be movable in the left-right direction and rotatably, and is inserted as a spacer between both main frames 8. Pins 12 and 13 are fixed from the outside to the upper ends of the two support parts 10 and 11, respectively. The pair of main frames 8 constitutes the carriage body 14.

Next, the printing mechanism 15 will be described.
A DC motor 16 is supported by the main frame 8 on the right side so as not to rotate itself, and a drive shaft 17 of this motor 16 is inserted through both main frames 8 and extends to the left,
The drive shaft 17 is located between the main frame 8 and the motor 16 side, and has a printing cam 18 having a generally side-viewed side view, and an encoder disk 1 having a plurality of slits formed on the outer peripheral portion thereof.
9, a ribbon supply cam 22 for stepwise feeding the print ribbon, and a raising cam 21 for raising and driving the holder member 32 to the erasing position are fixed to each other.

The print cam 18 and the ribbon supply cam 2
The cam body 20 is composed of 2 and the raising cam 21, and the ribbon supply cam 22 and the raising cam 21 are integrally formed as the cam body 20. In addition, in FIG.
The print start position is indicated by a dotted line, and the origin setting position is indicated by a two-dot chain line.

At the upper ends of the rear ends of both main frames 8, the central part of a turning lever 23 and the lower end of a link 24, which are generally V-shaped in side view, are pivoted by pins 25 and 26, respectively. The print hammer 27 which is supported and arranged in the front-rear direction so as to face the platen 3 is pivotally attached to the upper end of the link 24 at the rear end thereof, and is rotated at the center in the front-rear direction. It is pivotally attached to the upper end of the lever 23 so as to be rotatable.

Further, a cam follower 28 is rotatably attached to the front end of the rotating lever 23 so that the cam follower 2 can rotate.
A tension spring 29 is stretched between the upper end portion of the rotary lever 23 and the lower end portion of the link 24 so that 8 always contacts the cam surface of the printing cam 18.

Reference numeral 30 is a daisy wheel rotatably driven by a wheel drive motor and a wheel drive mechanism (not shown), reference numeral 31 is a ribbon cassette containing a print ribbon, and reference numeral 32 is a ribbon cassette 31 mounted thereon. In addition, it is a holder member that is vertically swingable via a support shaft 34 to an auxiliary frame 33 that is pivotally supported by the guide shaft 5 so as to be movable in the left-right direction. 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).

Therefore, the motor 16 causes the printing direction P in FIG.
When rotated by a predetermined angle, the cam follower 28 ascends along the cam surface of the printing cam 18, so that the rotating lever 23 rotates counterclockwise and the printing hammer 27 causes the daisy wheel 30 to print. The platen 3 is pressed through the print ribbon.

Adjustment plates 41 extending in the front-rear direction are provided outside the upper ends of both main frames 8, and oblong holes 8a formed in each main frame 8 at the front ends of both adjustment plates 41. The support shaft 42 inserted through is fixed,
Further, oval holes 41a are formed at the rear end portions of both adjusting plates 41, and both main frames 8 and both adjusting plates 41 have screws 4 inserted through these oval holes 41a.
It is screwed at 3. On the other hand, an engaging portion 44a that slidably engages with the rear end of the guide member 6 is provided at the front end of the contact member 44 whose rear end is rotatably supported by the support shaft 42. ing.

Next, an erasing mechanism 50 for raising the holder member 32 from the printing position to the erasing position so that the erasing ribbon faces the printing hammer 27 when erasing characters will be described with reference to FIG.
~ It demonstrates based on FIG.

The ascending cam 21 and the ribbon supplying cam 2
2 is formed as an integral cam body, and a raising cam 21 is formed on the left side of this cam body. A groove 2 having an equal radius from the center is formed on the outer peripheral portion of the cam 21.
1a is formed, and the shallow bottom portion 2 is formed in a part of the groove 21a.
1b is provided. The shallow bottom portion 21b is connected to the bottom surface of the groove 21a at a gentle slope. This groove 21
The inside of a is the second cam 21d. A first cam 21c having a smaller diameter and an equal radius than the second cam 21d is formed so as to project from the left end surface 21e of the second cam 21d.

The left end face 2 adjacent to the shallow bottom 21b
A part of 1e is cut out to form an inclined surface 21f that is inclined from the vicinity of the first cam 21c toward the shallow bottom portion 21b.

At a portion about 1/3 counterclockwise from the inclined surface 21f of the second cam 21d, the radius gradually increases from about 2/3 of the radius of the second cam 21d toward the outer circumference of the second cam 21d. A second inclined portion cam 21h that expands is formed. The second inclined cam 21h is provided with the groove 2 from the left end surface 21e.
It is gradually inclined toward the bottom surface of 1a to about 1/2. Therefore, the outer side of the second inclined cam 21h has the same radius as the second cam 21d, and the second cam 21d and the shallow bottom portion 2 are provided.
It becomes a connecting portion 21k that connects 1b. The shallow bottom portion 21b, the inclined surface 21f, and the connecting portion 21k constitute the fourth cam of the present invention.

The first cam 21c gradually projects from the vicinity of the inclined surface 21f in the counterclockwise direction to about ⅛ of the left end surface 21e to about ½ of the projection amount of the first cam 21d. A first inclined cam 21g is formed, and the first inclined cam 21g is formed from the outer periphery of the first cam 21c to the second inclined cam 21c.
The radius gradually increases toward the inclined surface 21f to about 1/3 of the radius of the cam 21d, and is connected to the second inclined portion cam 21h. The first inclined cam 21g and the second inclined portion cam 21h form a third cam of the present invention.

The outer peripheral wall 21i of the ascending cam 21 protrudes counterclockwise from a position facing the connecting portion of the second inclined cam 21h and the second cam 21d by an amount corresponding to about 1/4 of the entire outer peripheral wall 21i. The outer surface of this protruding portion serves as an outer peripheral cam 21j that engages with a second driven pin 54 described later.

Further, the first driven pin 52, which abuts on the ascending cam 21 from the left side, is movable in the left-right direction to the lower end portion of the support member 51 whose upper end portion is fixed to the side wall 32a at the left end portion of the holder member 32. And is always elastically biased to the right by the winding spring 53. Incidentally, this first driven pin 52
Thus, the cam follower of the present invention is formed.

At the start of printing of the first driven pin 52, as shown in FIG. 4, the tip end of the pin is brought into contact with the first cam 21C from above to move the holder member 32 to the printing position (reference swing) shown in FIG. Position) while supporting the end face 21f.
It is abutted from the left. That is, the swing amount of the holder member 32 is determined by the vertical movement of the first driven pin 52. Here, the printing cam 18 at the start of printing
The positional relationship between the ascending cam 21 and the first driven pin 52 is shown in FIG.

A second driven pin 54, which is parallel to the first driven pin 52, is formed on the support member 51 so as to project toward the ascending cam 21. The second driven pin 54 engages with the outer peripheral cam 21j as the ascending cam 21 rotates. During this engagement, the first driven pin 52 moves the second driven pin 52d.
The protruding position of the second driven pin 54 is determined so as to be slightly separated from the position. The second driven pin 54 forms a second cam follower.

Therefore, when the motor 16 rotates by a predetermined angle in the direction opposite to the printing direction P (hereinafter referred to as the anti-printing direction) from the phase angle at the start of printing shown in FIG. 4, the first driven pin 52 has the first inclination. Since the cam 21g moves upward, the holder member 32 also swings upward in accordance with the upward moving distance. After that, when the motor 16 is rotated in the printing direction P, the first driven pin 52 reaches the second cam 21d via the second inclined cam 21h, so that the holder member 32 swings further upward and switches to the erasing position. Be done.

By the way, when the first driven pin 52 reaches the connecting portion between the second inclined cam 21h and the second cam 21d,
The second driven pin 54 engages with the outer peripheral cam 21j. While the second driven pin 54 and the outer peripheral cam 21j are engaged, the first driven pin 52 is slightly separated from the second cam 21d (see FIG. 10). Due to this separation, the first driven pin 5
The end surface of 2 surely contacts the bottom surface of the groove 21a.

Therefore, even if the movement of the first driven pin 52 in the axial direction is not smoothly performed by the frictional resistance between the first driven pin 52 and the first inclined cam 21g and the second inclined cam 21h, Since the second driven pin 54 engages with the outer peripheral cam 21j and the first driven pin 52 is slightly separated from the second cam 21d, the first driven pin 52 surely moves in the axial direction, and the first driven pin 52 is moved. Does not return to the first inclined cam 21g or the second inclined cam 21h.

After the erasing operation is completed, when the ascending cam 21 rotates in the printing direction P, the first driven pin 52 moves the second cam 21d.
To reach the shallow bottom portion 21a via the connecting portion 21h. The holder member 32 includes the holder member 32 and the ribbon cassette 3
1 and the urging force of a spring member (not shown) that urges the holder member 32 toward the reference swing position, so that the first driven pin 52 reaching the shallow bottom portion 21a has the inclined surface 2
The first cam 21c is reached through 1f. After that, the ascending cam 21 rotates in the opposite printing direction to return to the printing start position, and the erasing operation ends.

Next, a print ribbon winding mechanism 60 for winding a predetermined amount of the print ribbon on the take-up spool for each printing operation.
Will be described with reference to FIGS. 3, 7, and 8.

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 ratchet 61 is rotatably supported by the pin 62 and the feed claw 6 is provided.
The third oscillating member 63 provided with 3a is connected to a second oscillating member 64 pivotally attached to the holder member 32 via a connecting pin 65, and the second oscillating member 64 has a tension spring 6
6 is elastically biased in the counterclockwise direction in FIG. The take-up spool 67 is fixed to the pin 62.

On the other hand, at the position of the ribbon feeding cam 22, the lower end portion of the first swinging member 69 is rotatably supported by the pivot pin 68 fixed to the left main frame 8, and the first swinging motion is performed. The upper end of the moving member 69 is in contact with the vicinity of the base end of the second swing member 64 from the front. Further, the ribbon supply cam 22 is located in a substantially circular hole 69a formed in the first swinging member 69, and the protrusion 69b of the first swinging member 69 is always provided in a part of the ribbon supply cam 22. The first swinging member 69 is elastically biased in the clockwise direction in FIG. 8 by the winding spring 70 mounted on the pivot pin 68 so as to abut.

Therefore, when the motor 16 is rotated in the counter-printing direction, the first swinging member 69 is formed in the counterclockwise direction in FIG. Since it is rotated from the forward position shown by to the retracted position shown by the solid line, the second rocking member 64 is rotated clockwise in FIG. 7 and the third rocking member 63 is rotated counterclockwise to feed. The ratchet 61 is rotated by one tooth by the pawl 63a, and the print ribbon is step-fed by a predetermined amount by the take-up spool 67 immediately before printing.

Next, the erasing ribbon winding mechanism 75 for winding a predetermined amount of the erasing ribbon on the winding spool at the time of erasing will be described with reference to FIGS. 2 and 9.

Side wall 32a at the rear end of the holder member 32
An erasing ribbon supply spool 76 is rotatably pivoted on the disk, and an erasing ribbon take-up spool 77 is rotatably pivoted on the right end thereof. The take-up spool 77 is provided with a ratchet 78 having a plurality of teeth, and a feed pawl 79 for rotating the ratchet 78 by one tooth is provided upright from an auxiliary frame (not shown) on the rear side of the ratchet 78. It is set up.

That is, as described for the erasing mechanism 50, when the phase angle of the motor 16 at the start of printing is set to 0 °, as shown in FIG.
~ As shown in FIG. 11, first, the motor 16 is set to a phase angle of 0 °.
When rotated by about 55 ° (hereinafter referred to as a phase angle of −55 °) from the opposite direction (see FIG. 9), the first driven pin 52 moves from a phase angle of −5 ° to a phase angle of −43 °. And the second tilt cam 21h after moving upward along the first tilt cam 21g.
Located on top. At this time, the first driven pin 52 is
This is a position that is elevated by about 2 mm with respect to the position of the cam 21a. 9 to 10, the raising 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.

And, here, the motor 16 is about -55.
When rotated in the printing direction P from 90 ° to + 90 °, the driven pin 52 moves on the second inclined cam 21h and then moves to the second
The cam 21d is reached (see FIG. 10). That is, at this time, the holder member 32 has the erasing ribbon with the printing hammer 27.
Is switched to the erase position opposite to. At this time, as described above, the second driven pin 54 engages with the outer peripheral cam 21j, so that the first driven pin 52 is slightly separated from the second cam 21d, and the end face of the first driven pin 52 becomes the bottom face of the groove 21a. Make sure they come into contact.

Here, at the position P1 during the movement, the feed claw 79 and the ratchet 78 start to engage with each other, and the position P2 is reached.
At, the ratchet 78 is rotated by one tooth. That is,
At this time, the erasing ribbon is wound by a predetermined amount on the take-up spool 77.
It is wound up and sent step by step. At this time, the first driven pin 52 is about 5.7 m from the position of the first cam 21c.
It is in a raised position.

Then, the motor 16 is moved to this + 90 °.
To the printing direction P and execute the erasing operation, the motor 1
When 6 rotates in the opposite printing direction to about -90 °, the first driven pin 52 moves from the second cam 21d to the shallow bottom 21b via the connecting portion 21k. 1st moved to shallow bottom 21b
The driven pin 52 descends to the first cam 21c through the inclined surface 21f as described above. Along with this lowering, the holder member 32 lowers to the printing position. On the other hand, during this movement, the feed claw 79 and the ratchet 78 are disengaged.

During this erasing operation, the first swinging member 69 is
As shown in FIG. 12, first, the motor 16 is rotated from 0 ° to −55.
After rotating from the forward position shown by the chain double-dashed line in FIG.
When it is rotated up to 90 °, it rotates clockwise and rotates to the forward position indicated by the chain double-dashed line. Further, the first swing member 69 is
While the motor 16 rotates in the counter-printing direction by approximately -90 °, it rotates counterclockwise from the forward position shown by the two-dot chain line in FIG. 8 to the retracted position shown by the solid line, and then again rotates clockwise. To return to the forward position.

Since the first driven pin 52 descends to the first cam 21c when the motor 16 rotates in the counter-printing direction to approximately -90 °, the holder member 32 also descends from the erasing position to the printing position for the first time at this time. .. At this time, as described above, the first
Since the swinging member 69 has moved to the retracted position away from the second swinging member 64, the second swinging member 69 is moved to the retracted position on the first swinging member 69.
It is prevented that the swinging member 64 rides up and the holder member 32 does not return to the print position, and the holder member 32 can be reliably lowered to the print position after the erasing operation is completed.

After that, the motor 16 drives the print direction P up to 0 °.
However, at this time, the first driven pin 52 only moves along the reference cam 21a via the position P6.

The cam body 20 can be indirectly rotatably driven by the motor 16 via a gear mechanism.

The ascending cam 21 is not limited to the shape of this embodiment, and it is possible to construct one or a plurality of various cams in combination.

[0052]

As described above, according to the printing apparatus of the present invention, the holder member at the erasing position can be reliably lowered to the printing position.

[Brief description of drawings]

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

FIG. 2 is a view on arrow 2 of FIG.

FIG. 3 is a partial front view of the internal mechanism of the electronic typewriter.

FIG. 4 is a side view of a main frame and an adjustment plate.

FIG. 5 is a left side view of the lifting cam.

FIG. 6 is a top view of a lifting cam.

FIG. 7 is a side view of a main part of the internal mechanism.

FIG. 8 is a view taken in the direction of arrow 8 in FIG.

FIG. 9 is a side view of the main parts of the internal mechanism at the print start position.

FIG. 10 is a view corresponding to FIG. 9 when the first driven pin moves to the second cam.

FIG. 11 is a diagram showing motion curves of a driven pin and a first swing member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic typewriter 3 Platen 14 Carriage main body 16 DC motor 18 Printing cam 20 Cam body 21 Lifting cam 21b Shallow bottom 21c First cam 21d Second cam 21f Sloping surface 21g First tilting cam 21h Second tilting cam 21k Connecting portion 27 Printing Hammer 30 Dizzy Wheel 31 Ribbon Cassette 32 Holder Member

Claims (1)

[Claims] 1. A carriage body driven to reciprocate in the left-right direction along a platen is provided with a type wheel and a printing hammer, and a holder member for mounting a printing ribbon and an erasing ribbon is provided on the carriage body. The end side is mounted so as to be positionally switchable by rotation between an erasing position where it is lifted up by a predetermined height and a printing position where it is not lifted up, and a cam follower is provided on the holder member, and the first cam follower is A first cam that holds the holder member at the printing position by sliding on the peripheral surface, a second cam that holds the holder member at the erasing position by sliding the cam follower on the peripheral surface, and a motor. A cam body provided with a third cam that guides the cam follower from the first cam to the second cam by at least rotating in the forward rotation direction of When the cam follower is moved from the second cam to the first cam by rotating the motor at least in the reverse direction, the cam follower is guided from the second cam to the first cam without engaging with the third cam. A printing device, wherein a fourth cam is provided on the cam body.