JPS5854674B2 - printing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing mechanism of a serial printer suitable for being attached to a display section of a small desktop calculator or a measuring machine.

Desktop calculators and measuring machines often display calculation results and measured values digitally on a liquid crystal display.

Moreover, recently it has become possible to record these calculation results and measured values on recording paper using many small serial printers.

This type of serial printer used in these devices is subject to considerable restrictions on the parts it can be mounted on, so it is desirable to make it as compact as possible. The reality is that it is difficult to miniaturize because it includes many complex mechanisms such as machinery, a hammer drive mechanism for printing, and a paper feeding mechanism.

In addition, recent desktop electronic calculators have various calculation functions, and for this reason, in addition to the numbers 0 to 9, it is required to print about the same number of function symbols as these 10 numbers as print data. .

However, if numbers and function symbols are housed in the same type wheel, the diameter of the type wheel becomes large, which increases the size of the entire printer, making it unsuitable for use as a printer, especially for portable desktop electronic computers.

To solve this problem, the applicant previously proposed a serial printer in which the type wheel for function symbols and the type wheel for numbers are separated, and only the type wheel for numbers is moved in the direction of the digits. did.

This application, as shown in Japanese Patent Application Laid-Open No. 52-46930, associates two type wheels with hammer bodies that each operate independently.

For this reason, the mechanism becomes complicated because two hammer bodies are selectively operated by the same driving source.

The applicant of this application has also previously developed a serial printer in which two type wheels are selectively struck by a single hammer body, eliminating the selection mechanism for the two hammer bodies mentioned above.
The application was filed as No. 514.

The above-mentioned JP-A-52-46930 and JP-A-53-5
The serial printer shown in No. 6514 has a simple mechanism, is small in size, and is lightweight, making it ideal for mounting on desktop electronic computers and the like.

However, the pulse motor for rotating the type wheel,
Since a relatively large electromagnetic plunger is used to drive the type wheel shift and drive the hammer body, and a relatively large electromagnetic plunger is used to feed the paper and release the carriage, the cost of parts for the drive source and the space it occupies are reduced. It was a big win.

On the other hand, a serial printer using two type wheels in which character selection, printing, digit feeding, paper feeding, etc. are performed by a single motor has been proposed in Japanese Patent Laid-Open No. 54-68325.

However, since the above-mentioned motor is configured to rotate in forward and reverse directions, there is a certain limit to improving the printing speed, and in addition, the motor is relatively expensive and its control is complicated.

In addition, the mechanism is complicated because it is necessary to select and lock each of the two type wheels separately.

The present invention is a novel invention that improves the conventional drawbacks as described above, and its purpose is to provide a small and lightweight serial printer.

Another object of the present invention is to provide a serial printer that reduces the number of drive sources as much as possible, reduces the space occupied by the drive sources, and is suitable for attachment to a compact and lightweight hand-held desk computer. .

Another object of the present invention is to rotate a motor as a drive source in a constant direction at all times, and to provide a rotation transmission means for transmitting the rotation of the motor to a predetermined rotation shaft as necessary. The aim is to improve printing speed.

Still another object of the present invention is to reduce the number of rotating shaft structures as much as possible to make the structure of a serial printer compact.

Still another object of the present invention is to simplify and downsize the mechanism by effectively utilizing the rotation of the rotary shaft to perform the printing operation and the shift operation on one axis.

Next, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a plan view of a printing device according to the present invention.
is an iron frame plate.

Side plates 1a and lb are attached to the frame plate 1 so as to face each other.

Note that 1c is a support plate that supports the upper ends of the side plates 1 a y 1 b.

A rail 2 is hung between the side plates 1a and 1b.

A carriage 3 is movable left and right along the rail 2, that is, in the direction of the girder.

4 is a type wheel for printing function symbols, and 5 is a type wheel for printing numbers, which are held on the carriage 3.

A rotating shaft 6 passes through each type ring.

Each type wheel is rotated by the rotary shaft 6, but the rotary shaft 6 can be freely moved in the axial direction within a predetermined range independently of each other.

Reference numeral 1 designates a tension spring, one end of which is fixed to the side plate 1a and the other end of which is fixed to the carriage 3, pulling the carriage 3 to the initial position, that is, the position shown in FIG.

Reference numeral 8 denotes a moving wire or thread that moves the carriage 3 (pulls it in the direction of the arrow).

Note that 9 is a guide member that guides the tension spring 7, and 10 is a guide member that guides the tension spring 7.
are guide members for the shift wire 8, and the side plates 1a,
1b.

11 is a printing mark, and there is a notch 1 on the right end to prevent printing.
It has 1a.

A non-circular hammer cam 12 drives the printing hammer 11 and is attached to a drive shaft 13.

14 is a recording sheet inserted between the printing hammer 11 and the type wheel 4.5, 5b is an ink roller, and 15 is a stopper disk.

First, before giving a detailed explanation of the drive mechanism, the printing operation will be explained.

When the rotary shaft 6 rotates and a desired function symbol comes to the printing position, the drive shaft 13 rotates and the hammer cam 12 presses the printing hammer 11.

For this purpose, the printing hammer 11 presses the recording paper 14 against the type wheel 4, and the function symbol is printed.

Note that at this time, since the type ring 5 is located in the notch 11a, no numbers are printed.

When printing of the first digit is completed, the shift wire 8 is pulled in the direction of the arrow to shift the carriage 3 to the left by one digit.

At this time, the type wheel 5 held by the carriage arm 3a shifts to the second digit, but although the type wheel 4 is pushed to the left by the spring 14', it does not follow the movement of the carriage 3. It stops at a position facing the notch 11a of the printing hammer 11, and thereafter remains at this position until one line of printing is completed and the carriage returns.

(Although not shown, the type wheel 4 comes into contact with a step provided on the shaft 6.

) On the other hand, when the carriage 3 shifts to the second digit and the desired number comes to the printing position, the printing operation as described above is performed.
The digit is printed.

After such a printing operation continues, when one line of printing is completed, the winding member of the shift wire 8 becomes free.

Therefore, the carriage 3 returns to the initial position shown in the first diagram by the tensile force of the tension spring 1, and the printing operation for one line is completed.

(If necessary, please refer to the above-mentioned Japanese Unexamined Patent Publication No. 53
See No.-56514.

) Next, details of the printing mechanism will be explained.

The printing mechanism according to the present invention includes (1) a rotating shaft mechanism that rotationally drives the type wheels 4 and 5, (2) a shaft mechanism that rotates the hammer cam 12 for driving the printing hammer, and (3) feeding the recording paper. It has three paper feed shaft mechanisms, which are organically connected using a gear mechanism and a clutch mechanism to perform various sequence operations.

(1) A second rotating shaft mechanism that rotationally drives the type wheels 4 and 5.
In the figure, reference numeral 16 denotes a fixed bearing, which is fitted into a half-moon-shaped hole 1b-1 in the side plate 1b so as not to rotate, and the rotating shaft 6 is inserted through the center hole i6a.

Reference numeral 17 denotes a reverse rotation prevention ring, which is tightly fitted to the rotating shaft 6 and rotates integrally therewith.

Reference numeral 18 denotes a coil spring for preventing reverse rotation, which is wound in a direction that unwinds when the rotating shaft 6 is twisted in a predetermined rotational direction.

The fixed bearing 16 and the anti-reverse wheel 17 are provided with drum parts 16b and 17a having the same diameter.
The sides of b and 17a are in close contact.

A coil spring 18 is wound around these drum parts.

Note that the inner diameter of the coil spring 18 is slightly smaller than the outer diameter of each drum portion.

When the rotating shaft 6 is rotating in a predetermined direction,
Since the coil spring 18 is driven in the direction of unwinding,
Although the drum parts 16b and 17a are separated, if the rotating shaft 6 tries to rotate even slightly in the opposite direction, the coil spring 1
8 tightens the drum parts 16b and 17a so that they are connected, and the rotating shaft 6 cannot be rotated in the opposite direction.

A gear 19 is loosely fitted to the rotating shaft 6 and has a drum portion 19a.

20 is a holding cylinder, and on one side is a drum part 19 of the gear 19.
It has a hole 20a through which it passes, and a groove 2ob is formed on the outer periphery.

21 is a cylindrical body having a drum portion 21a on one side and a groove 21b formed on the circumferential surface.

22 is a coil spring, and bent end portions 22a and 22b are formed at both ends.

Reference numeral 23 denotes a ratchet gear, which has a boss portion 23a on one side, and is formed hollow inside so as to accommodate a clutch to be described later.

When assembling the clutch part 21A, first, one end 22b of the coil spring 22 is inserted into the groove 21b of the cylindrical body 21, and approximately half of the coil spring 22 is fitted into the drum part 21a of the cylindrical body 21 ( The inner diameter of the coil spring 22 is slightly smaller than the outer diameter of the drum parts 19a and 21a, which have the same diameter).

Next, the drum part 19a of the gear 19 is inserted into the hole 2 of the holding cylinder 20.
The remaining coil spring 22 is press-fitted into the drum part 19a, and the other end 22a of the coil spring is inserted into the groove 20b of the holding cylinder 20.

That is, each member 19, 20, 21 is connected via a coil spring, and is coupled so as to rotate together in a predetermined direction (the tension direction of the coil spring).

In addition, during assembly, the holding cylinder 20 is rotated by a small amount with respect to a ratchet gear 23, which will be described later, to absorb variations in the relative angles of both ends 22a and 22b of the coil spring 22 (which causes difficult errors in manufacturing). It is now possible to do so.

Then, the cylindrical body 21 of the members assembled as described above is press-fitted and firmly fitted into the rotating shaft 6, and then the ratchet gear 23
is placed on the cylindrical body 21.

At this time, each member is attached to the rotating shaft 6 by aligning the fan-shaped protrusion 21d provided on the other drum part 21c of the cylindrical body 21 with the fan-shaped hole 23c that communicates with the center hole 23b at the end of the ratchet gear 23. It looks like this.

In addition, when the fan-shaped protrusion 21d and the fan-shaped hole 23c are engaged with each other, the holding tube 20 is adjusted and rotated as described above to achieve a predetermined installation position.

In addition, the engagement relationship between the fan-shaped protrusion 21d and the fan-shaped hole 23c is designed to allow a slight margin, and is designed to smooth the tension and loosening of the coil spring 22 when the clutch is operated, which will be described later. .

The coil spring 18 and the coil spring 22 are set to wind in directions opposite to each other with respect to the rotation direction of the rotating shaft 6, and when the gear 19 rotates in response to the rotation of a motor, which will be described later, the coil spring 22 rotates. is transmitted to the rotating shaft 6 via the cylindrical body 21 by the connection of the coil spring 22, and rotates together with the ratchet gear 23 when its rotation is prevented by a locking member to be described later. The rotation of the cylindrical body 21 is also stopped, and the coil spring 22 is immediately loosened, cutting off the rotational transmission between the gear 19 and the cylindrical body 21 (ie, the rotating shaft 6).

When the rotating shaft 6 attempts to rotate in the opposite direction (the opposite direction to the rotation caused by the motor drive) when the rotating shaft 6 stops rotating, the aforementioned coil spring 18 immediately moves between the fixed bearing 16 and the anti-reverse ring 1.
7 to prevent reverse rotation of the rotating shaft 6.

(2) Shaft mechanism for rotating the hammer cam 12 for driving the printing hammer In FIG. 3, 24 is a fixed bearing, which is fitted into the half-moon-shaped hole 1b-2 in the side plate 1b so as not to rotate. The drive shaft 13 is inserted through the center hole 24a.

Reference numeral 25 denotes a reverse rotation prevention wheel, which is tightly fitted to the drive shaft 13 and rotates integrally therewith.

Reference numeral 26 denotes a coil spring for preventing reverse rotation, which is wound in a direction that unwinds when the drive shaft 130 is twisted in the direction of rotation.

The fixed bearing 24 and the anti-reverse ring 25 are provided with drum parts 24b and 25a having the same diameter.
The sides of 5a are closely spaced.

A coil spring 26 is wound around these drum parts.

Note that the inner diameter of the coil spring 26 is slightly smaller than the outer diameter of each drum portion.

When the drive shaft 13 is rotating in a predetermined direction, the coil spring 26 is driven in the direction in which it is unwound, so the drum parts 24b and 25a are separated, but even if the drive shaft 13 is If an attempt is made to rotate in the opposite direction, the coil spring 26 tightens the drum parts 24b and 25a, so that they are connected, and the drive shaft 13 cannot rotate in the reverse direction.

A gear 27 is loosely fitted onto the drive shaft 13, and a ratchet gear 27a is fixedly formed on the side surface of the gear 27 as a single piece.

28 is a clutch plate that rotates together with the drive shaft 13.

The clutch plate 28 has two notches 28a in the diametrical direction on its outer periphery.

28d, a hole 28b on the side to fit the tip 29a of the pin 29 to fix the pin, and a body 28c on the side around which the helical spring 30 is wound.

Both ends of the helical spring 30 are bent outward to form a tip 30a.
, 30b.

31 is a locking plate. Two notches 31a and 31b are formed in the outer periphery of the stopper plate 31 in the diametrical direction, and the center has a circular hole 31c through which the drive shaft 13 passes, and an elongated hole 31d raised along the circumference. and a long hole 3 raised in the radial direction.
1e.

32 is a ratchet pawl. Holes 32a and 32b are provided at both ends of the ratchet pawl 320, and a pawl 32c is provided in the center.
is formed.

33 is a pin, and 34 is a split washer.

The clutch 35 portion is assembled as follows.

After fitting and fixing the tip 29a of the pin 29 into the hole 28b of the clutch plate 28 and inserting the narrow diameter part 33a of the pin 33 into the long hole 31e of the locking plate 31, the narrow diameter part 33a is inserted into the ratchet pawl 32. It is fitted and fixed into the hole 32b.

The helical spring 30 is fitted to the body 28c of the clutch plate 28, and the tip 30a is hooked to the pin 29.

Next, the circular hole 31c of the locking plate 31 is inserted into the body portion 28c.

At this time, the pin 29 is inserted through the long hole 31d of the locking plate 31 and into the hole 32a of the ratchet pawl 32, and the tip 30b of the helical spring 30 is hooked on the narrow diameter portion 53a of the pin 33.

Finally, the split washer 34 is fitted onto the tip of the pin 29.

The drive shaft 13 is inserted into the center of the clutch 35 assembled in this manner, and the clutch plate 28 and the drive shaft 13 are connected, and the pawl 32c is engaged with the ratchet gear 27a.

When the gear 27 is rotated in the direction of the arrow from this state, the ratchet gear 27a hooks and pulls the ratchet pawl 32, so the clutch plate 28 also rotates and the drive shaft 13 rotates.

During rotation, when claws (not shown) are fitted into the notches 28a and 31a, the clutch plate 28 and the locking plate 31
Since the ratchet gear 27 of the gear 27, which is constantly rotating in conjunction with the motor, presses the ratchet pawl 32, the ratchet pawl 32 has an elongated hole 31 d y 3.
1 move outward along e, thus ratchet gear 2
1 and the ratchet pawl 32 are disengaged, and the connection between the gear 27 (ie, the motor) and the clutch plate 28 (ie, the drive shaft 13) is severed.

At this time, even if the drive shaft 13 tries to rotate in the reverse direction, the aforementioned reverse rotation prevention mechanism by the coil spring 26 works, and the drive shaft 13
cannot be rotated in reverse.

(3) Paper feed shaft mechanism for sending recording paper In FIG. 4, 36 is a fixed bearing, which is fitted in a half-moon-shaped hole 1b-3 on the side plate 1b so as not to rotate. The paper feed shaft 37 is inserted.

Reference numeral 38 denotes a reverse rotation prevention ring, which is tightly fitted to the paper feed shaft 37 and rotates integrally therewith.

39 is a coil spring for preventing reverse rotation, and paper feed shaft 370
It is wound in a direction that unwinds when twisted in the direction of rotation.

The fixed bearing 36 and the anti-reverse wheel 38 are provided with drum parts 36b and 3ga having the same diameter.
The sides of 8a are closely spaced.

A coil spring 39 is wound around these drum parts.

Note that the inner diameter of the coil spring 39 is slightly smaller than the outer diameter of each drum portion.

When the paper feed shaft 37 is rotating in a predetermined direction, the coil spring 39 is driven in the direction in which it is unwound, so the drum parts 36b and 38a are separated, but the paper feed shaft 37 is If the paper feed shaft 3T tries to rotate even slightly in the opposite direction, the coil spring 39 tightens the drum parts 36b and 38a, so that they are connected, and the paper feed shaft 3T cannot be rotated in the reverse direction.

40 is a gear loosely fitted to the paper feed shaft 37, and a ratchet gear 40a is fixed to the side surface.

A clutch plate 41 rotates together with the paper feed shaft 37.

- The clutch plate 41 has a hole 41a through which the narrow diameter portion 42a of the pin 42 is inserted and fixed, and a body portion 41b on the side around which the helical spring 43 is wound.

Both ends of the helical spring 43 are bent outward to form a tip 43a.
, 43b.

44 is a locking plate.

Five teeth 44a are provided on the outer periphery of the locking plate 44, a circular hole 44b is provided in the center through which the paper feed shaft 37 passes, and a long hole 44c raised along the circumference and a circular hole 44b are provided in the radial direction. It has a raised elongated hole 44d.

45 is a ratchet pawl. Holes 45 a t 45 b are provided at both ends of the ratchet pawl 450, and pawl 4 is provided in the center.
5c is formed.

46 is a pin, and 47 is a split washer. Next, clutch 4
The eight parts are assembled as follows.

After fitting and fixing the tip 42a of the pin 42 into the hole 41a of the clutch plate 41 and inserting the narrow diameter part 46a of the pin 46 into the long hole 44d of the locking plate 44, the narrow diameter part 46a is inserted into the ratchet pawl 45. The helical spring 43 is fitted into the body 41b of the clutch plate 41 which is fitted and fixed into the hole 45b, and the tip 43a is hooked onto the pin 42.

Next, the circular hole 44b of the locking plate 44 is inserted into the body portion 41b.

At this time, the pin 42 is inserted through the long hole 44c of the locking plate 44 and into the hole 45a of the ratchet pawl 45, and the helical spring 43
The tip portion 43b of the pin 46 is hooked onto the narrow diameter portion 46a of the pin 46.

Finally, the split washer 47 is fitted onto the tip of the pin 42.

The paper feed shaft 37 is inserted into the center of the clutch 48 assembled in this way, and the clutch plate 41 is connected to the paper feed shaft 37 with a strong fit, and the pawl 4 is attached to the ratchet gear 40a.
Engage 5c.

Then, a claw 50a provided at the tip of an arm 50 fixed to a paper feed command shaft 49 pivotally supported by the side plate 1b engages with teeth 44a of the locking plate 44 to prevent rotation of the locking plate 44. .

In addition, 51 is a small gear attached to the rotating shaft of a drive motor (not shown), and 52 is a shaft 5 attached to the side plate 1b.
The gear 52a is in mesh with the small gear 51, and the gear 52b is in mesh with the gear 40.

When the gear 40 is rotated in the direction of the arrow from this state, the ratchet gear 40a hooks and pulls the ratchet pawl 45, so the clutch plate 41 also tries to rotate, but the pawl 50a pressed by the spring engages the tooth 44a of the locking plate 44. rotation is prevented.

When the ratchet pawl 45 tries to rotate due to the rotation, the ratchet pawl 45 is pushed toward the outer circumference along the long hole 44ct44d of the locking plate 44 and escapes, so that the pawl 45c of the ratchet pawl 45
The gear 40a is disengaged from the ratchet gear 40a, and only the gear 40 rotates without rotating the shaft 37.

Note that when the arm 50 rotates in response to a paper feed command and the engagement between the claw 50a and the tooth 44a of the locking plate 44 is temporarily disengaged, the paper feed shaft 3T is rotated by the gear 40, and when the predetermined paper feed is completed. (When the locking plate 44 rotates 115 times), the spring engages the pawl 50a and the tooth 44a again, and the clutch 48 prevents the rotation of the gear 40 from being transmitted to the paper feed shaft 3T.

The explanation of the three axes has been completed above, but when these three axes are assembled, the gear 40 supported on the paper feed shaft 37 and the gear 27 supported on the drive shaft 13 mesh with each other. The gear 27 and the gear 1 supported on the rotating shaft 6
9 meshes with each other, and the rotation of the small gear 51 is ultimately caused by the rotation of the gear 1.
9 and they all rotate at the same time.

Note that the side plate 1b is provided with a switching drive mechanism that switches clutches provided on the rotating shaft 6 and the drive shaft 13.

In FIG. 5, 53 is the switching plate, 54 is the drive magnet, and 55 is the same (tension spring).

The switching plate 53 has slots 53a elongated in its longitudinal direction at both ends.
, 53b is formed, and a locking piece 53c is formed in the center, and a sulin) 53d is formed at the bottom of the elongated hole 53a.
is formed.

The long hole 53a is supported by the rotating shaft 6, and the long hole 53b is supported by the drive shaft 13 so as to be movable in the left-right direction.

When the switching plate 53 is located at one end, the stop piece 53c engages with the ratchet gear 23, and when the switching plate 53 is located at the other end, the stop piece 53c engages with the notch 31a or 31b of the locking plate 31 and the notch of the clutch plate 28. 28a or 28b.

An arm 54a is rotatably supported on the drive magnet 54, and when the coil 54b is energized, the arm 54a is attracted against the spring 55.

FIG. 6 is a side view of the printing mechanism seen from the side plate 1b.

As is clear from this drawing, the drive magnet 54 is fixed to the side plate 1b with a screw 56, the tip 54a' of the arm 54a engages with the slit 53d of the switching plate 53, and the tension spring 55 is attached to the arm 54a and the side plate 1b. The locking piece 53c is stretched between the upright balls 51, and engages the locking piece 53c with the clutch plate 28 and the locking plate 31 when the magnet 54 is not activated.

FIG. 7 is an exploded perspective view showing the mechanism on the side plate 1a side. In the figure, reference numeral 58 denotes a locking arm, which is supported on the rotating shaft 6 and can rotate independently of the rotation of the rotating shaft 60.

A helical spring 59 always applies a rotational force in the direction of the arrow.

A claw 58a is formed at the tip of the locking arm 58, and a protrusion 58b is formed at the inside.

10 is a rotary encoder fixed to the rotating shaft 6.

60 is a feed pawl fixed to the drive shaft 13, which includes two pawls 60a, 60b and a kick pawl 60c in the diametrical direction.

60d (partially not shown) is provided.

61 is a pentagonal cam body which is fixed to the paper feed shaft 37 and rotates therewith, and 62 is a take-up gear which is supported on the paper feed shaft 37 and can be separated from the waste paper feed shaft 3T and rotated freely.

A gear 62a and a ratchet gear 62b are formed on the winding gear 62, and some teeth of the gear 62a are cut out by several pitches to form a tooth-missing portion 62c.

Further, a drum portion 62d is formed between the ratchet gear 62b and the gear 62a, and a shift wire (or thread) 8 coupled to the carriage 3 is wound around the drum portion 62d.

A release arm 63 is rotatably supported on a shaft 64 provided on the side plate 1a.

The release arm 63 has two cam valleys 63a, 63b and one cam peak 63c, and has a protrusion 63d below the cam valley.

Reference numeral 65 designates an engaging arm fixed to the paper feed command shaft 49, and has a slit 65a formed at its tip.

Reference numeral 66 denotes a guide ball provided upright on the side plate 1a, the tip of which is fitted into a slit (not shown) provided on the back surface of the winding gear 62 to determine the initial position of the winding gear. This is the stopper member.

When the respective parts disposed on the side plate 1a are assembled and the carriage 3 is in the initial position, the release arm 63
The protrusion 58b of the locking arm 58 is fitted into the cam valley 63a, keeping the claw 58a at the tip away from the ratchet gear 62b, and the take-up gear 62 is in a free state.

Further, the protrusion 63d of the release arm 63 is in contact with the flat surface of the cam body 61.

FIG. 8 is a side view of the printing mechanism seen from the side plate 1a side.

As is clear from this drawing, the engagement arm 65 is
At 65a, there is a tip 6 of an L-shaped operating arm 67a of a magnet 67 that is energized when a command to wind up the printing paper is issued.
7b is loosely fitted.

68 is a contact piece 6 that comes into contact with the rotary encoder 70
This is a terminal board that holds 9.

Next, a series of printing operations in the printing mechanism according to the present invention will be explained.

As shown in FIG. 1, when the motor starts rotating in response to a printing command from the rightmost position, that is, the initial position, as described above, the gears 19 and 27 degrees provided in the three shaft mechanisms rotate. All 40 rotate.

Since the clutch 21A connected to the gear 19 is in a connected state, the ratchet gear 23 and the rotating shaft 6 rotate,
Therefore, the mouth-tally encoder 10 and the type wheels 4, 5 are also rotating.

When the desired function type comes to the printing position, the drive magnet 54 (FIG. 6) is energized and the switching plate 53 is moved to the sixth position.
Move it to the left in the figure.

Therefore, the locking piece 53c of the switching plate 53 meshes with the ratchet gear 23 to stop it.

Note that FIGS. 9a and 9b are cross-sectional views showing the state before and after the switching plate 53 is switched.

When the ratchet gear 23 is stopped, as described above, the clutch 21A of the rotating shaft 6 is disengaged, the rotating shaft 6 is stopped, and only the gear 19 rotates.

On the other hand, when the switching plate 53 moves, this locking piece 53c engages with the notch 28a of the clutch 35 (FIG. 3).

31a (Fig. 9a).

Therefore, the clutch 35 is in a connected state, and the drive shaft 1
3 rotates, and during the initial rotation, the hammer cam 12 presses the printing hammer 11 (if diagram) to print the function symbol.

When the drive shaft 13 further rotates, the feed pawl 6 in FIG.
0 rotates in the direction of the arrow, and the kick claw 60c or 60d kicks the tip 63e of the release arm 63 in the direction of the arrow, that is, downward, causing it to rotate, causing the protrusion 5gb of the locking arm 58 to fall into the cam valley 63b.

As a result, the locking arm 58 rotates in the direction of the arrow in FIG. 1, engages the pawl 58a with the ratchet gear 62b, and
2. Prevents reversal.

From now on, the kick claw 60 is used until the carriage returns.
The c t 60d and the release arm 63 cannot come into contact with each other.

When the feed pawl 60 continues to rotate, the pawl 60b, which is out of phase with the kick pawl, meshes with the gear 62a, causing the take-up gear 62 to rotate.

When this rotates, the shift wire 8 moves to the drum part 6.
2d, and the carriage 3 is moved.

The above series of operations is performed by the drive shaft 130 half rotations.

During this time, the biasing force of the drive magnet 54 is released, so the switching plate 53 is moved to the right in FIG.
and 31b or 28a and 31a, and disengages from the ratchet gear 23.

As a result, the clutch 21A is in a connected state and the clutch 35 is in a disengaged state, so that the rotary shaft 6 rotates and the type wheels 4 and 5 begin to rotate, while the drive shaft 13 stops.

When the desired number to be printed on the second digit comes to the printing position, the drive magnet 54 is again excited and the switching plate 53 is again moved to the left in FIG.

Therefore, the locking piece 53e of the switching plate 53 meshes with the ratchet gear 23 to stop it.

When the ratchet gear 23 is stopped, the clutch 21A of the rotating shaft 6 is disengaged, the rotating shaft 6 stops, and the gear 19 idles.

On the other hand, when the switching plate 53 moves, this locking piece 53C comes off from the notch 28bj31d of the clutch 35.

Therefore, the clutch 35 is in a connected state and the drive shaft 13
rotates, and the hammer cam 12 presses the printing hammer 11 to print the required number.

When the drive shaft 13 rotates, as shown in FIG.
is rotated in the direction of the arrow, and the pawl 60a or 6ob is the gear 62a.
, and rotates the take-up gear 62 by one tooth in the same manner as described above.

When this rotates, the shift wire 8 moves to the drum part 6.
2d, and the carriage 3 is moved by one more digit against the tension spring 7 mentioned above.

When the feed pawl 60 rotates half a turn, the pawl 60a and the gear 62a are disengaged, and the single digit feed operation is completed.During this time, the excitation of the drive magnet 54 is released, so the switching plate 53 is moved by the tension spring 55. After the drive shaft 13 moves to the right in FIG.
and 31a or 28d and 31b, and the ratchet gear 23 is disengaged.

Therefore, the clutch 21A becomes connected, the clutch 35 becomes disconnected, the rotating shaft 6 rotates, and the type wheel 4
, 5 start rotating, the drive shaft 13 stops, and the printing operation of the second digit number is completed.

This printing operation is repeated several times to print the desired number of digits, and when one line of printing is completed, the magnet 67 (Fig. 8) is energized and the actuating arm 67a is moved clockwise. Rotate.

Therefore, the engaging arm 65 is lifted up against the spring 71 and rotated counterclockwise, thereby rotating the paper feed command shaft 49.

Therefore, the arm 5 on the side plate 1b side that rotates integrally with the shaft 49
0 rotates, and as shown in FIG.
As shown in FIG. 11, the pawl 50a that had been engaged with the clutch 48 is temporarily disengaged from the teeth 44a of the locking plate 44, and the clutch 48 is brought into a connected state.

Therefore, the paper feed shaft 37 begins to rotate and feeds the recording paper 14 by a predetermined pitch.

When the paper feed shaft 37 begins to rotate, the cam body 61 (FIG. 7) that rotates integrally with the paper feed shaft 37 also begins to rotate, and the cam body 61 pushes up the protrusion 63d of the release arm 63, as shown in FIG.

This action causes the protrusion 58b of the locking arm 58 to move into the cam valley 6.
3b to 63a to disengage the pawl 58a and the ratchet gear 62b.

Therefore, the take-up gear 62 becomes free.

Note that the protrusion 58b of the locking arm 58 is located in the valley 6 of the release arm 63.
3b, both 58 and 63 maintain a mechanically balanced state, and the above-mentioned kick claw 60c of the feed claw 60,
This state is maintained until the release arm 63 is pushed downward by 60d.

In other words, an attempt is made to ensure carriage return.

When the gear 62 becomes free, the carriage 3 is moved by the tension spring 7.
Because it is constantly pulled in the direction of the initial position,
While pulling the shift wire 8, it quickly returns to the initial position.

The shift wire 8 then rotates the take-up gear 62 to return it to its initial position.

As explained in detail above, the printing device according to the present invention includes:
A rotation transmission means is provided between the rotation shaft for driving the type wheel, the drive shaft for driving the print head, and the motor, and the rotation transmission between the two can be turned on or off. This not only reduces the number of drive sources, but also allows the motor to always rotate in a fixed direction, making it compact and
A lightweight serial printer with high printing speed can be provided.

In addition, since the rotation transmission means is turned on or off and the printing operation and shift operation are performed by rotating the drive shaft, the mechanism is extremely simple and the operation is reliable.

[Brief explanation of the drawing]

Figure 1 is a plan view of the printing device, Figure 2 is an exploded perspective view of the rotating shaft mechanism that rotates the type wheel, Figure 3 is an exploded perspective view of the drive shaft mechanism that drives the printing hammer cam, and Figure 4 is an exploded perspective view of the drive shaft mechanism that drives the printing hammer cam. Figure 5 is an exploded perspective view of the paper feed drive shaft mechanism, Figure 5 is an exploded perspective view of the two-shaft mechanism for rotating the print hammer and type wheel, Figure 6 is a right side view, Figure 7 is
The figure is an exploded perspective view of the main part showing the mechanism on the left side, Figure 8 is a left side view, Figures 9a and b are sectional views showing the operating state of the clutch part, and Figures 10 and 11 are the clutch operating part. FIG. 12 is an exploded perspective view showing a mechanism for releasing the carriage. In the figure, 1 is a frame body, 3 is a carriage, 4 and 5 are type wheels,
6 is a rotating shaft, 1 is a tension spring, 8 is a shift wire, 11
1 is a printing hammer, 13 is a drive shaft, 15 is a stopper disc, 1
T is a reverse rotation prevention wheel, 18 is a coil spring, 19 is a gear, 20
is a holding cylinder, 21 is a cylindrical body, 21A is a clutch, 22 is a coil spring, 23 is a ratchet gear, 25 is a reverse rotation prevention wheel,
26 is a coil spring, 27 is a gear, 28 is a clutch plate, 2
9 is a pin, 30 is a helical spring, 31 is a locking plate, 32 is a ratchet pawl, 33 is a pin, 35 is a clutch, 37 is a paper feed shaft, 38 is a reverse rotation prevention ring, 39 is a coil spring, 40 is a gear, 41 is a clutch plate, 42 is a pin, 43 is a helical spring, 4
4 is a locking plate, 45 is a ratchet pawl, 46 is a pin, 48 is a clutch, 49 is a paper feed command shaft, 50 is an arm, 51 is a small gear, 52 is an intermediate gear, 53 is a switching plate, 54 is a drive magnet, 55 is a tension spring, 56 is a screw, 5T is a pole, 58 is a locking arm, 59 is a spiral blade, 60 is a feed pawl, 61 is a cam body, 62 is a winding gear, 63 is a release arm, 64
65 is a locking arm, 66 is a guide pole, 67 is a magnet, 68 is a terminal plate, 69 is a contact piece, and 70 is a rotary encoder.

Claims (1)

[Claims] 1. A serial printer that performs printing by moving a type wheel in the digit direction has a rotating shaft that rotates integrally with the type wheel, a printing hammer that strikes the type wheel, and a drive shaft that is attached with a hammer cam that drives the printing hammer. , a gear train that connects the motor and the gears on the rotating shaft and the gears on the drive shaft, and a gear train that is located between the rotation transmission path of the motor and the rotation shaft, and between which rotation transmission is on or off. A first rotation transmission means that can change the state and a rotation transmission path between the drive shaft and the motor, and the rotation transmission between them is ON or OFF.
and a second rotation transmission means that can take two states,
When the rotary shaft is rotating, the rotation of the motor cannot be transmitted to the drive shaft, and when the type wheel is selected and stopped, the rotation of the motor is transmitted to the drive shaft, and the rotational force of the drive shaft drives the printing hammer and the type. 1. A printing device characterized in that the printing device performs digit feeding of a ring.