JPH0320353B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing device that performs printing by moving a type member in the digit direction, and particularly relates to a printing device that uses a differential mechanism to send a first output of the differential mechanism to the type member and print a second output. The present invention relates to a compact printing device that can be used in pocket calculators, etc., which is connected to a mechanism and selectively prints characters by alternately switching first and second outputs.

Conventional examples of switching selective printing using a differential mechanism include Japanese Patent Publication No. 48-13365 and Japanese Patent Publication No. 13365-1973.
112617 can be raised. However, in both cases, a type member, a printing mechanism, and a selection mechanism are mounted on the carriage, and the shape of the carriage is complicated and large. Furthermore, in the former case, selection of desired type is extremely complicated and requires a large number of electromagnets. Further, in both cases, there is no detailed explanation regarding carry, and a carry mechanism using a different method unrelated to the differential mechanism is required. Also, as a conventional example of a carry mechanism,
81610 describes a device using racks and carry cams, but the type selection is very complicated.
Furthermore, the printing mechanism has a structure in which the type head itself is swung by a tab mounted between frames, making the device complicated and large. Currently, there is a demand for calculators equipped with printing devices to be smaller and lighter, but it is extremely difficult to make them smaller and lighter if they have a large and complicated carriage like the device mentioned above, or even have a complicated selection printing mechanism. It was hot.

The present invention eliminates such drawbacks, and aims to reduce the size and weight of the carriage by reducing the number of mechanisms mounted on the carriage.
The objective is to reduce the size of the entire device.

Another object of the present invention is to simplify the apparatus by using a differential mechanism for switching selective printing, and to make the apparatus compact and lightweight.

Still another object of the present invention is to simplify the apparatus by performing selection, printing, and carry operations simply by switching the differential mechanism.

In the printing device according to the present invention, a first output of a differential mechanism connected to a drive mechanism is connected to a type member, a second output is connected to a printing mechanism, and the first output and the second output are alternately switched by a selection mechanism. A serial printer that performs selective printing of type includes a carriage that is supported so as to be movable in the digit direction, a printing shaft that is mounted over the range of movement of the carriage and is rotationally driven by a second output, and the direction of movement of the carriage. a positioning member provided with a plurality of teeth corresponding to the printing digits; a type member rotatably held by a carriage; a type member rotatably driven by a first output and having type letters arranged on its outer periphery; a hammer member that prints on printing paper by pressing it, a printing cam equipped with a cam lead that rotates as the printing shaft rotates and drives the hammer member, and a carriage whose position in the direction of the digits is regulated, and A cam lead that engages is provided, and a carry cam that is non-rotatably supported on the printing shaft and is moved in the digit direction as the printing shaft rotates, and the cam leads of the printing cam and the carry cam drive the hammer member. It is characterized in that it is arranged on the print shaft in a positional relationship in which the drive of the carry cam is performed alternately.

An embodiment of the present invention will be explained in detail using the drawings. 1st
The figure is a plan cross-sectional view, and is composed of a selection mechanism 1, a paper feed mechanism, a carriage return mechanism 2, and a carriage 3. Second
The figure is a side view of the selection mechanism 1, Figure 3 is a side view of the paper feed and carriage return mechanism 2, and Figure 4 is a perspective view of the selection mechanism 1, paper feed and carriage return mechanism 2 in the direction of arrow A in Figure 1. It is a view seen from the bottom.

An overview of each mechanism will be explained.

(1) Selection mechanism Motor 6 fixed to frame 5, motor gear 7 fixed to motor shaft 6a, motor gear 7
The reduction gear 8 includes a gear 8a that meshes with the planetary gear 8, a shaft portion 8b that supports the selection drive gear 9, a sun gear 8c that meshes with the planetary gear 10, and a shaft 9a that supports the planetary gear 10. The printing switching cam 11 is an internal gear 1 that meshes with the planetary gear 10.
1a, selection claw 12 (second and fourth
Notch 1 on the outer periphery that engages with the claw 12a in the figure).
A cam 11c, which is a control member, has a protrusion 11 on the outer periphery that engages with the claw 12b of the selection claw 12.
d, a cam 11f that engages with part 13a of the positioning lever 13 (FIGS. 3 and 4), and a gear 11g that meshes one-on-one with the printing gear 15 fixed to the printing shaft 14. The reduction gear 8 and the printing switching cam 11 are supported by a shaft 17 that is mounted between the frames 5 and 16. The sun gear 8c, the planetary gear 10, the internal gear 11a, and the selection drive gear 9 constitute a planetary gear differential mechanism. The selection claw 12 is supported by a shaft 19 that is mounted between frames 16 and 18, and is supported by a spring 2 that is an operating member.
0 in the direction of arrow B. The selection gear 21 meshes with the selection drive gear 9, and the selection pawl 12
a selection ratchet wheel 21b having regularly arranged teeth 21a on the outer periphery that engages with the pawl 12c;
Type shaft 22 mounted between frames 16 and 18
is fixed to. The trigger lever 23 includes a shaft 23a that supports the trigger planetary gear 24, a shaft 23b that engages with a portion 12d of the selection claw 12, and a positioning lever 13.
It is comprised of a portion 23c that engages with a portion 13b of , and is pivotally attached to the type shaft 22 and biased in the direction of arrow C by a spring 25. The trigger sun gear 37 is integrally formed with the paper feed clutch ratchet wheel 37a and is fixed to the type shaft 22. The brake gear 26 meshes with the trigger planetary gear 24 and has a brake disc 27 made of magnetic material.
It has a pin 26a that engages with a hole 27a provided in the hole 27a. The electromagnetic brake yoke 28 is made of a magnetic material, has an opening 28a facing the brake disc 27, and has a coil 29 disposed inside. brake gear 26,
The brake disc 27 and the electromagnetic brake yoke 28 are supported by a shaft 32 mounted on frames 30 and 31.
The electromagnetic brake yoke is non-rotatably attached to the frame 31. The electromagnetic brake, which is an electromagnetic member, is composed of an electromagnetic brake yoke 28, a brake disc 27, and a coil 29.

The selection mechanism 1 is configured by the above elements.

(2) Paper feed and carriage return mechanism The positioning lever 13 has a 13a portion that engages with the cam 11f of the print switching cam 11, a 13b portion that engages with the 23c portion of the trigger lever 23, a 13c portion that supports the paper feed trigger lever 33, and a paper A portion 13d that engages with a portion 33a of the feed trigger lever 33, and a protrusion 13 that engages with a protrusion 34a of the positioning transmission lever 34.
e, which is pivoted to the shaft 19 (not shown) and is biased in the direction of arrow D. The paper feed trigger lever 33 is connected to the paper feed clutch pawl 35 at 3
It has a section 33b that engages with section 5a, and is biased in the direction of arrow E by a spring 36. The paper feed clutch pawl 35 has a gear 38a that meshes with the paper feed transmission gear 39, is supported on a shaft 38b provided on a paper feed drive gear 38 which is supported on the type shaft 22, and has one end fixed to the paper feed drive gear 38. The paper feed drive gear 38 has one end supported on the shaft 38b.
It is biased in the direction of arrow F by a spring 40 fixed to . Furthermore, the paper feed clutch pawl 35 has a pawl 35b that engages with teeth 37b of a paper feed clutch ratchet wheel 37a, which has teeth 37b regularly arranged on its outer periphery. The paper feed gear 47 is fixed to a shaft 48 to which a paper feed roller 49 is fixed.
It meshes with a paper feed transmission gear 39 which is supported on a shaft 66 which is mounted at 0,43. The positioning transmission lever 34 is supported by the shaft 19 at a portion 34b that engages with the end cam 15a of the printing gear 15, and has a plurality of teeth 4 in a part thereof.
It has a portion 34c that engages with a portion 41b of the positioning plate 41, which is biased in the direction of arrow G by a compression spring 42 (FIG. 5).

The paper feed and carriage return mechanism 2 is configured by the above-mentioned elements.

(3) Carriage A type belt 50 having a type 50a on the outer periphery and a protrusion 50b inside the type 50a, and a type 51a.
Type belt 51 having protrusion 51b, type 5
The type belt 52 having the 2a protrusion 52b is attached to a type holder 53 which is slidably but non-rotatably attached to the type shaft 22. The type holder 53 has a cylindrical shape and has a type belt 50 on the outer periphery.
Holes are provided so that the protrusions 50b, 51b, and 52b of 51 and 52 are loosely fitted, respectively. The type belts 50, 51, and 52 are made of an elastic material such as rubber. Type holder 53
is held in the carriage frame 54 so as to be movable by a certain amount, and is biased in the opposite direction of arrow H by a type spring 65. The carriage frame 54 is guided by the type shaft 22 and the print shaft 14 and is movable in the direction of arrow H. The hammer 55 is supported by a shaft 54a provided on the carriage frame 54, is biased in the direction of arrow I by a spring 56, is held between portions 54b and 54c of the carriage frame 54, and is non-rotatable but slidable on the printing shaft 14. One end 55a is engaged with an end surface 57a of a printing cam 57 mounted on the printer. Further, the other end 55b is the protrusion 50b or 51 of the type belt 50 or 51, 52.
b, 52b.
1 that meshes with the teeth 41a of the positioning plate 41 on the outer periphery
A carry cam 58 having a striped cam 58a is held between 54d and 54e of the carriage frame 54 and is non-rotatably but slidably mounted on the printing shaft 14.

The carriage 3 is composed of the above elements.

Next, a series of operations will be explained.

(1) Initial settings Perform initial settings before starting selection and printing. The carry cam 58 is disengaged from the tooth 41a of the positioning plate 41 by the method described later (as shown by the two-dot chain line in FIG.
4f, the direction is changed by a spring guide roller 62 whose other end is supported by a shaft 61 fixed to the frame bottom plate 60, and the carriage 3 is attached to a spring hook 59 provided on the frame bottom plate 60 to attach the carriage 3 in the opposite direction of arrow H. The returning spring 63 moves the carriage 3 in the opposite direction of the arrow H and brings the 54g portion of the carriage frame 54 into contact with the carriage stopper 64 fixed to the frame 18 (the first
figure). At this time, the portion 53a of the type holder 53 also comes into contact with the carriage stopper 64 and moves within the carriage frame 54 while compressing the type spring 65, and the portion 55b of the hammer 55 stops at a position corresponding to the type belt 50. The type spring 65 is set to be weaker than the return spring 63. The selection claw 12 has a spring 20 that causes the claw 12a to engage the notch 11b of the cam 11c, and the claw 12c escapes from the teeth 21a of the selection ratchet wheel 21 (solid line in Figure 2). The trigger lever 23 is held by the spring 25 at a position where the portion 23c is in contact with the portion 13b of the positioning lever 13 (solid line in FIGS. 2 and 3).

(2) Selection of the first digit As the motor 6 rotates, the motor gear 7 moves to the arrow J.
direction, thereby rotating the reduction gear 8 and the planetary gear 10 in the directions of arrows K and L, respectively. At this time, since the print switching cam 11 is locked by the pawl 12a, the internal gear 11a cannot rotate. Internal gear 11a
cannot rotate, so the planetary gear 10 is the sun gear 8c.
The selection drive gear 9 rotates in the direction of arrow K via the planetary shaft 9a. The rotation of the selection drive gear 9 causes the selection gear 21 to rotate in the direction of arrow O, and further rotates the type shaft 22, the trigger drive gear 37, the trigger planetary gear 24, the brake gear 26, the brake disc 27, and the type holder 53. The desired type is selected by the type 50a using a well-known method.
The energization of the coil 29 is controlled using a character position signal generated by a detection means (not shown) which generates a character position signal in response to the character position signal. The coil 29 is energized shortly before the desired type faces the platen 44 mounted on the frames 18, 43. When the coil 29 is energized, the brake disc 27 is attracted to the electromagnetic brake yoke 28, and since the electromagnetic brake yoke 28 cannot rotate, the rotation of the brake disc 27 is stopped. When the rotation of the brake disc 27 stops, the rotation of the brake gear 26, which is locked by the pin 26a, also stops. Even when the rotation of the brake gear 26 stops, the trigger planetary gear 24 continues to rotate, so it rotates on the trigger drive gear 37 in the direction of the arrow N and revolves in the opposite direction of the arrow C, and moves the trigger lever 23 via the shaft 23a to the spring 25. Rotate in the opposite direction of arrow C while resisting the spring force. The rotation of the trigger lever 23 is performed by rotating the selection pawl 12 in the opposite direction of arrow B using the portion 23b, and the pawl 12c is rotated by the tooth 21 of the selection pawl wheel 21b.
a to stop the rotation of the selection ratchet wheel 21b (dashed line in FIG. 2). When the selection ratchet wheel 21b is locked, the rotation of the type shaft 22 and type holder 53 is also stopped, and the desired type 50a is stopped on the opposite surface of the platen 44, and the selection is completed (FIG. 6).

(3) Printing of the 1st digit and carrying up When the trigger lever 23 rotates, the selection pawl 12 rotates in the opposite direction of arrow B to select the desired character, and at the same time the pawl 12a and the notch 11b are disengaged and the print switching cam 11 rotation becomes free. At this time, since the rotation of the selection ratchet wheel 21b is stopped by the pawl 12c, the rotation of the selection gear 21 and the selection drive gear 9 is also stopped. Therefore, the rotation of the planetary gear 10 causes the internal gear 11a, that is, the print switching cam 11, to rotate in the direction of arrow P. The rotation of the print switching cam 11 rotates the print gear 15, the print shaft 14, the print cam 57, and the carry cam 58. When the printing cam 57 rotates, the cam lead of the cam end face 57a rotates the hammer 55 in the opposite direction of arrow I, and the 5 of the hammer 55 is rotated.
The portion 5b engages with the protruding portion 50b of the type belt 50, causing the type belt 50 to protrude from the inside, and the type 50
A is pressed onto the platen 44 via the printing paper 45 and printed (two-dot chain line in FIG. 6). In addition, type 50a
Ink is applied to the surface using an ink roll or the like (not shown) using a well-known method. 7th
The figure shows a time chart of the operation of each element during one rotation of the printing switching cam 11, that is, the printing shaft 14. 1
01 is the energization of the coil 29, 102 is the trigger lever 23, 103 is the operation of the selection claw 12, 104 is the rotation of the type shaft 22, and 105 is the print switching cam 1.
1. Rotation of the printing shaft 14, 106 is the printing cam 57
107 is the cam lead of the upper cam 58, 108 is the arrow G of the positioning transmission lever 34.
109 indicates the operation of the positioning lever 13, 110 indicates the paper feed trigger lever 33, and 111 indicates the operation of the positioning plate 41. The power supply to the coil 29 is cut off when the print switching cam 11 starts rotating (solid line in FIG. 7), but the selection claw 12 is turned off by the claw 12a.
engages with the outer periphery of the cam 11c to maintain the operating state.
In the trigger lever 23, the coil 29 is de-energized and the brake disc 27 is free to rotate, so the trigger planetary gear 24 and the brake gear 2 are moved by the action of the spring 20.
6. Rotate in the direction of arrow C while rotating the brake disc 27 to return to the standby state (solid line in Figure 2).
As soon as the printing gear 15 starts rotating, the end cam 15a provided on the printing gear 15 moves the positioning transmission lever 34 in the opposite direction of the arrow G, disengaging the positioning lever 13 from the protrusion 13e and allowing it to rotate freely. Since the positioning plate 41 engaged with the positioning plate 41 is urged in the direction of the arrow Q by the spring 46, it rotates in the direction of the arrow Q, and the teeth 41a mesh with the cam 58a of the carry cam 58 (solid line in FIG. 10). The cam 11f of the printing switching cam 11 is approximately 100°
When rotated, the notch 11b moves into the positioning lever 1.
However, since the trigger lever 23 has already returned to the standby state, the positioning lever 13 does not operate because the positioning lever 13b is locked by the part 23c. Therefore, the protrusion 34 of the positioning transmission lever 34
a and the protrusion 13e of the positioning lever 13 come into contact with each other, and the positioning transmission lever 34 does not move in the direction of the arrow G even when the cam 15a of the printing gear 15 is removed, and the positioning transmission lever 34 does not move in the direction of the arrow G, and the positioning transmission lever 34 does not move in the direction of arrow G, and the positioning transmission lever 34 does not move in the direction of the arrow G, and the positioning transmission lever 34 does not move in the direction of the arrow G, and the positioning transmission lever 34 does not move in the direction of the arrow G, and the cam of the positioning plate 41 and the cam of the digit cam 58 The engagement with 58a is maintained. The printing shaft 14
When the printing operation is completed after rotating 180 degrees and further rotating, the cam 58a of the digitizing cam 58 meshes with the teeth 41a of the positioning plate 41, and the cam lead causes the digitizing cam 58 to engage with the teeth 41a of the positioning plate 41.
moves in the direction of arrow H. When the digit cam 58 moves, the carriage frame 54 that holds the digit cam 58, as well as the printing cam 57 and the hammer 55, move simultaneously, but there is a gap δ1 between the type holder 54 and the carriage frame 54 (Fig. 1). ), the carriage frame 54 moves, but the type holder 53 is maintained in a state in which the portion 53a is in contact with the carriage stopper 64 due to the action of the type spring 65 (FIG. 8). At this time, a portion 55b of the hammer 55 corresponds to the type belt 51. When the printing switching cam 11 rotates approximately 330 degrees, the claw 12a corresponds to the notch 11b, so the selection claw 12 rotates in the direction of arrow B by the action of the spring 20 and locks the printing switching cam 11 again, completing printing and carrying. do. The protrusion 11d of the cam 11e of the printing switching cam 11 and the claw 1
2b engages when the notch 11b starts, assists the action of the spring 20, and rotates the selection claw 12 in the direction of arrow B.

(4) Selection of the second digit The selection pawl 12 rotates in the direction of arrow B and locks the print switching cam 11, and at the same time the pawl 12c and the selection pawl wheel 21b are unlocked, as detailed in the selection of the first digit above. The selection gear 21 rotates again, and the desired type is selected. At this time, the difference from the selection of the first digit is that in the first digit, the desired type to be selected is selected from the group of type provided on the type belt 50, but in the second digit, as shown in FIG. Selected from a set of characters provided.

(5) Printing of the second digit and carry-up The printing is done in the same way as the printing of the first digit explained in detail above. The difference is that for the first digit, the type belt 50 is projected from the inside and pressed against the platen 44 to print, but for the second digit, the type belt 51 is protruded from the inside and pressed against the platen 44 to print, as shown in Figure 8. That's true. Carry is carried out by the cam 58a of the carry cam 58 and the tooth 41a of the positioning plate 41 meshing with each other, and the carriage 3 being moved in the direction of arrow H by the cam lead, in the same way as the first digit carry. At this time, the difference from the previous time is that the gap δ2 between the type holder 53 and the carriage frame 54 is set to be slightly smaller than the carry position, so the type holder 53 comes into contact with the carriage frame 54 and moves slightly in the direction of arrow H. The portion 55b of the hammer 55 corresponds to the type belt 52 (FIG. 9).

(6) Selection of the third digit This is done in the same way as the selection of the second digit. The difference from the second digit is that in the second digit, the characters selected are from the group of characters on the character belt 51, but in the third digit, they are selected from the group of characters on the character belt 52 (FIG. 9).

(7) Printing and carrying of the third digit Printing is done in the same way as the second digit. The difference from the second digit is that the characters that are projected from the inside and are pressed and printed on the platen 44 are the characters of the group of characters on the character belt 52. Carry is carried out in the same way as for the second digit. The difference from the second digit is that although the carriage 3 moves by one digit, the type holder 53 and the carriage frame 54 are already in contact with each other, so the condition shown in FIG.
5b corresponds)).

(8) Selection, printing, and carry after the 4th digit This is done by repeating steps (6) and (7) detailed above.

(9) Selection of the most significant digit, printing, paper feeding, and carriage return The time chart (Fig. 7) corresponds to the two-dot chain line.Selection is made in the same way as before, but at the most significant digit, the coil is immediately de-energized. The energization is maintained until the print switching cam 11 rotates approximately 145 degrees as shown by the two-dot chain line 101 in the time chart (FIG. 7). When the print switching cam 11 rotates 100 degrees, the notch 11h of the cam 11f corresponds to the portion 13a of the positioning lever 13. At this time, the trigger lever 23 maintains its operating state (as indicated by the two-dot chain line in FIGS. 2, 3, and 7) because the coil 29 is not energized. Therefore, the positioning lever 13 is rotated in the direction of arrow D by a spring (not shown) (two-dot chain line in FIG. 3). When the positioning lever 13 rotates, the paper feed trigger lever 33 is also rotated in the opposite direction of arrow E by the 13d portion of the positioning lever 13.
The engagement between the portion 3b and the portion 35a of the paper feed clutch pawl 35 is released. When the paper feed clutch pawl 35 is released, it rotates in the direction of arrow F by the action of the spring 40, causing the pawl 35b and the paper feed clutch pawl wheel 37a to rotate.
meshes with the tooth 37b (two-dot chain line in Fig. 3). At this time, since the type shaft 22 has stopped rotating, the paper feed clutch pawl wheel 37a has also stopped rotating, but the teeth 37b correspond to the type characters 50a of the type belt 50, and are further engaged with the pawls 35b at the stopped position. Since the claws 35b and the teeth 37b are provided in the same manner as shown in FIG. When the print switching cam 11 further rotates, the positioning lever 13 is rotated in the opposite direction of arrow D by the cam lead 11i of the cam 11f and returns to the standby state. Since the paper feed trigger lever 33 operates the paper feed clutch pawl 35 which rotates in the direction of arrow E by the spring 36, the portion 33b is the paper feed clutch pawl 3.
It comes into contact with part 35c of No. 3 and stops. The carriage return is performed as follows. Positioning lever 13
When rotates in the direction of arrow D, the protrusion 13e and recess 13f of the positioning lever 13 face the recess 34d and protrusion 34a of the positioning transmission lever 34, respectively. When the printing switching cam 11 rotates 145 degrees, the lead of the end cam 15a of the printing gear 15 disappears, and the positioning transmission lever 34 moves in the direction of arrow G due to the action of the spring 42, and the protrusion 13e and recess 13f of the positioning lever 13 become the positioning transmission lever. 34
The recess 34d and the protrusion 34a are engaged with each other (solid lines in FIG. 5). Print switching cam 11 is approximately 190°
When rotated, the positioning lever 13 is rotated in the opposite direction of arrow D by the cam lead 11i and returns to the standby state. At this time, the positioning transmission lever 34 is engaged with the positioning lever 13, so it rotates in the opposite direction of arrow D, and furthermore, the positioning plate 41 has its 41b section engaged with the 34c section of the positioning transmission lever 34, so that
It is rotated in the opposite direction of arrow Q, and the cam 58a of the spar cam 58 and the teeth 41a of the positioning plate 41 are held in a disengaged state (as shown by the two-dot chain line in FIG. 10). When the positioning plate 41 and the carry cam 58 are disengaged, the carriage 3 returns to the standby state (first digit) by the action of the return spring 63. When the coil 29 is de-energized, the trigger lever 23 returns to the standby state by the action of the spring 25. When the print switching cam 11 rotates once and the type shaft 22 starts rotating again, the paper feed clutch pawl wheel 37a also rotates. At this time, the paper feed clutch pawl 3 is attached to the tooth 37b.
Since the pawls 35b of No. 5 are engaged, the paper feed clutch pawl 35 and the paper feed drive gear 38, which supports the paper feed clutch pawl 35 on the shaft 38b, also rotate in the direction of arrow R. When the paper feed drive gear 38 rotates, a portion 33b of the paper feed trigger lever 33 comes into contact with the outer periphery 38c of the drive gear 38 due to the action of the spring 36. When the paper feed drive gear 38 rotates once, the 33b portion of the paper feed trigger lever 33 and 35a of the paper feed clutch pawl 35 are engaged again, and the engagement between the paper feed clutch pawl 35 and the paper feed clutch pawl wheel 37a is released, and the paper is fed. The rotation of the drive gear 38 is stopped. The rotation of the paper feed drive gear 38 is controlled by the paper feed transmission gear 39.
The paper feed gear 47, paper feed shaft 48, and paper feed roller 49 are rotated via the paper feed roller 49, and the printing paper 45 is fed by one line.

If you want to print the next line, follow steps (2) to (9) above.
Just repeat. In addition, when used in a calculator etc., if symbols are placed on the type belts 50 and 51 and numbers are placed on the type belt 52, symbols can be printed on the first and second digits and numbers can be printed on the third and higher digits. can.

In the printing device according to the present invention, a hammer member driven by a printing cam that rotates as the printing shaft rotates presses the type to print on printing paper, and is provided with a cam lead that engages with teeth provided on the positioning member. The carriage is moved in the digit direction by a carry cam that is moved in the digit direction as the printing shaft rotates.The rotation of the printing shaft performs the carry movement and printing operation of the carriage, making it possible to print with a simple mechanism. The device was realized.

[Brief explanation of the drawing]

Fig. 1 is a plan sectional view of a printing apparatus according to the present invention, Fig. 2 is a side view of the selection mechanism, Fig. 3 is a side view of the paper feed and carriage return mechanism, and Fig. 4 is a side view of the selection mechanism, paper feed and carriage return. Fig. 1 is a perspective view of the mechanism seen from the bottom in the direction of arrow A; Fig. 5 is a plan sectional view of the carriage return mechanism; Fig. 6 is a side sectional view of the type member;
The figure is a time chart, FIG. 8 is a state diagram in which the carriage is in the second digit, FIG. 9 is a state diagram in which the carriage is in the third digit, and FIG. 10 is a side sectional view of the carry mechanism. 1... Selection mechanism, 2... Paper feed carriage return mechanism, 3... Carriage, 6... Motor, 8...
Reduction gear, 9... Selection drive gear, 10... Planetary gear, 11... Print switching cam, 12... Selection claw, 1
3...Positioning lever, 14...Printing shaft, 21...
Selection gear, 22... Type shaft, 23... Trigger lever, 27... Braking disc, 28... Electromagnetic brake yoke, 29... Coil, 34... Positioning transmission lever, 35... Paper feed clutch pawl, 37a ...Paper feed clutch ratchet wheel, 38...Paper feed drive gear, 41
...Positioning plate, 50, 51, 52... Type belt, 53... Type holder, 54... Carriage frame, 55... Hammer, 57... Printing cam, 5
8... Carry cam.

Claims (1)

[Scope of Claims] 1. A first output of a differential mechanism connected to a drive mechanism is connected to a type member, a second output is connected to a printing mechanism, and the first output and the second output are alternately switched by a selection mechanism. A serial printer that performs selective printing of type, comprising: a carriage supported so as to be movable in the digit direction; a printing shaft that extends over the range of movement of the carriage and is rotatably driven by the second output; and the carriage a positioning member provided with a plurality of teeth corresponding to the printing digits in a moving direction; a type member rotatably held by the carriage, rotationally driven by the first output, and having type characters arranged on its outer periphery; a hammer member that is held by the carriage and presses the type to print on printing paper; a printing cam that is provided with a cam lead that rotates with the rotation of the printing shaft and drives the hammer member; a carry cam whose position in the direction is regulated, a cam lead that engages with the teeth, and a carry cam that is moved in the digit direction with rotation of the printing shaft that is non-rotatably supported on the printing shaft; A printing device characterized in that a printing cam and a cam lead of the carry cam are arranged on the printing shaft in a positional relationship such that driving of the hammer member and driving of the carry cam are performed alternately.