JPS6160791B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small serial printer.

Conventional printers of this type include flying hammer printers in which a printing hammer is pressed into contact with a character wheel that rotates at a constant speed and can move horizontally for each digit, and prints on printing paper interposed between the two. Are known. In this printer, in order to increase the printing speed, it is necessary to increase the rotation speed of the character wheel, so it is difficult to match the timing between the operation of the printing hammer and the character part of the character wheel. However, there is a drawback that characters are likely to be misaligned or parts of characters may be missing, resulting in unclear printing. Therefore, there are known configurations in which a motor, for example a pulse motor, is used to rotate the character wheel intermittently at a fixed angle, or an electromagnetic device such as an electromagnetic clutch is used to stop the rotating character wheel during printing operations. In such a method, the cost and space of the motor and the electromagnetic device relative to the entire printer are large, which hinders the reduction in cost and size of the printer.

The present invention was proposed in view of the above-mentioned conventional problems, and uses a single DC motor as a drive source for various mechanisms to provide intermittent motion to a character wheel that rotates continuously at a constant speed by a simple means. It is an object of the present invention to provide a serial printer that is small in size, low cost, and can print clearly.

The present invention will be explained below with reference to illustrated embodiments.

The printer shown in FIG. 1 has a number wheel 1 as a character wheel and a symbol wheel 2 adjacent thereto, and a gear 4 fixed to a common shaft 3 of both wheels 1 and 2 has side plates 5a and 5b.
The driving force of the DC motor 6 provided between the gears 7, 8,
9, and both vehicles 1 and 2 except during printing operations.
It is configured to rotate at a constant speed. The number wheel 1 is returned to its original position in the left direction in the figure with respect to the shaft 3, that is, in the direction in which the digits go up, by a carry mechanism to be described later. The symbol wheel 2 does not move in the axial direction of the shaft 3. 1a and 2a indicate ink rollers.

Opposed to the number wheel 1 and symbol wheel 2, a number printing hammer 10 and a symbol printing hammer 11 are rotatably supported on a rotating shaft 12 extending between both side plates 5a, 5b, and the two side plates 5a, 5b and each hammer 10,
The pressure contact portions 10a, 11a are held in a downward direction by a tension coil spring (not shown) stretched over the hammer 11, and the lower part of each hammer is brought into contact with a stopper 13 (FIG. 2). Pressing part 10 of the number printing hammer 10
A is formed long to accommodate the movement of the number wheel 1. Both hammers 10 and 11 are configured to operate one of them by a switching mechanism which will be described later.

Each mechanism will be explained below.

(a) Printing mechanism (Figs. 1 and 2) 15 is a first clutch release lever rotatably supported by a shaft 16 attached to one side plate 5a, and has a permanent magnet 17 at the bottom. is the iron core 1 of solenoid 18 when printing is not performed.
8a as shown in the figure. The tip of the first clutch release lever 15 is in contact with the tip of the first clutch lever 19. The first clutch lever 19 has a lower end rotatably attached to a holding plate 21 rotatably supported by a shaft 20 of the gear 8 through a shaft 22, and a tip portion attached to a pin 23 of the holding plate 21. It is biased counterclockwise by a tension coil spring 24. A ratchet 25 is fixed to the shaft 20 in correspondence with the pawl 19a at the center of the first clutch lever 19. The above holding plate 21
has a claw 21a on its circumferential surface and a cam 26 coaxially
has. The cam lever 27 below the first clutch lever 19 is rotatably supported by a shaft 28 attached to the side plate 5a, and one end is connected within the rotation locus of the cam 26, and the other end is connected to a carry mechanism to be described later. 29 is the cam lever 27 and the pin 30 of the side plate 5a.
This is a tension coil spring installed between the At the top of the cam lever 27, a lever 31 for pressing the printing hammer is rotatably supported by a shaft 32 attached to the side plate 5a, and a pin 31a at the lower end is connected to the cam lever 27.
The upper bent portion 31b is brought into contact with a pin 33a fixed to the hammer rotating shaft 12 on the rotation locus of the hammer.

As shown in FIG. 1, the number printing hammer 10
The symbol printing hammer 11 has a stepped part at the rear, and when printing numbers, each convex part 10b of the number printing hammer is attached to two pins 3 fixed to the rotating shaft 12.
3b, and the recessed portion 11c of the symbol printing hammer 11 also faces the pin 33c. On the other hand, when printing a symbol, each recess 10c of the symbol printing hammer 10
is opposite the pin 33b, and the symbol printing hammer 1
The first convex portion 11b faces the pin 33c. Reference numeral 34 denotes a pull-up spring for the first clutch release lever 15, which is actually built into the bearing cover 16a of the shaft 16. 35 is a return spring attached to the lever 15, and 36 is a stopper for the lever 15 attached to the side plate 5a.

In the above configuration, when the solenoid 18 is energized by, for example, a number printing signal, the permanent magnet 17
The adsorption force of the first clutch release lever 15 decreases, and the first clutch release lever 15
is rotated counterclockwise by the pull-up spring 34,
It hits stoppa 36. First clutch lever 19
Since the clutch disengages from the first clutch release lever 15, it is pulled by the coil spring 24 and rotates counterclockwise, causing its pawl 19a to engage with the ratchet 25 rotating counterclockwise. This engagement causes the holding plate 21 to rotate, and the cam 26 to rotate together with the holding plate 21, thereby rotating the cam lever 27 clockwise against the coil spring 29. The rotation of the cam lever 27 is controlled by the printing hammer pressure contact lever 3 via the pin 31a.
1 and rotates the lever 31 counterclockwise. Due to this rotation, the lever bending portion 31b pushes the pin 33a to rotate the hammer rotating shaft 12, and the pin 33b pushes the convex portion 10 of the number printing hammer 10.
b is pressed to rotate the hammer 10 counterclockwise to bring the pressure contact portion 10a into pressure contact with the number wheel 1 which has stopped rotating, thereby recording a predetermined number on the printing paper P between both 10a and 1. At this time, the pin 33 of the rotating shaft 12
c also rotates, but the recess 1 of the symbol printing hammer 11
1c, the movement is allowed and the hammer 11 does not operate. Details of this operation will be described later.

As the holding plate 21 rotates, its pawl 21a comes into contact with the return spring 35 of the first clutch release lever 15, and the lever 15 rotates clockwise against the pull-up spring 34, pulling the permanent magnet 17 into the iron core of the solenoid. 18a and returns to the original position. When the rotating first clutch lever 19 comes into contact with the tip of the first clutch release lever 15, it is disengaged from the ratchet 25, stops rotating, and enters a standby state. At that time, the first clutch lever 19
Excessive return movement is prevented by the pin 37 of the retaining plate 21.

The operation from the first clutch lever 19 to the hammer rotating shaft 12 due to the operation of the first clutch release lever 15 is the same when the symbol printing hammer 11 is operated. However, each pin 33b, 33c
and uneven portions 10c, 11c of each hammer 10, 11,
The engagement relationship between 10b and 11b is switched as described above.

(b) Character wheel stopping mechanism (FIGS. 1 and 3) As mentioned above, the character wheel is configured to stop when the printing hammer is activated, and this configuration will be explained using the number wheel 1 as an example.

As shown in FIG. 3, the number wheel 1 has a ratchet 38 that is coaxially integrated with it and has each claw corresponding to each number part, and the ratchet 38 is rotatable on a bearing 39 fixed to the shaft 3. is mated to.
The bearing 39 and the ratchet 38 are connected to a spiral spring 4 wound in a direction opposite to the direction of rotation of the shaft 3 (clockwise).
Connected by 0. 41 is a set screw, 4
2 is a spring insertion groove formed in the bearing 39. A number wheel stopper 43 is located between the ratchet 38 and the pressure contact portion 10a of the number printing hammer 10.
The stopper 43 is made of a leaf spring, and has an arcuate portion 43b facing the ratchet 38 and having a claw portion 43a.
and a linear attachment portion 43c. The arc portion 43b has a radius of curvature larger than the radius of the number wheel 1, and is closer to the pressure contact portion 10a of the number printing hammer 10 than the circumferential surface of the number wheel 1 when a printing operation is not performed. The mounting portion 43c is fixed to the number chassis 44 with screws 45.
The number chassis 44 is slidable on a shaft 46 provided between the side plates 5a and 5b.

In the above structure, the number wheel 1 and the ratchet 38 are normally rotated clockwise together with the shaft 3 via the spiral spring 40. When the numeric printing hammer 10 rotates counterclockwise in response to the numeric printing signal as described above, its pressure contact portion 10a presses the stopper 43 via the printing paper P, causing its claw portion 43a to engage with the ratchet 38. Due to this engagement, the number wheel 1 stops rotating, and the stop is caused by the spiral spring 40.
is temporarily maintained by deflecting outward.
During this time, the pressing part 10a of the hammer presses the printing paper P against the number part of the number wheel to record the number.

As the hammer 10 returns after the above-mentioned printing operation, the stopper 43 disengages from the ratchet 38 while pushing back the printing paper P with its elasticity, and the number wheel 1 quickly rotates due to the restoring force of the spiral spring 40 and returns to its original position. It returns to normal and rotates at a constant speed.

The above mechanism is also installed on the symbol car.

(c) Carry mechanism (Figures 1 and 4) After the printing operation following the stop of the number wheel mentioned above, number wheel 1
is shifted one digit to the left in FIG. This carry mechanism will be explained below.

47 is a carry rope winding drum rotatably supported by a shaft 48 attached to the side plate 5a.
One end of the carry rope 49 is fixed to the circumferential surface of the drum 48 with a screw 50, and the other end is passed through a hole in the side plate 5a to the number wheel side plate 5 integral with the number wheel chassis 44.
1 with screws 52. A pair of left and right side plates 51 are provided, and the side plates 51 are slidable relative to the shaft 3, and support the shaft 1c of the ink roller 1a on the upper part. One end of the return rope 53 is fixed to the other number wheel side plate 51 with a screw 54, and the other end is wound around a return rope winding drum 56 through a guide 55 attached to the side plate 51. The drum 56 is connected to a shaft 57 provided between the side plates 5a and 5b.
is rotatably supported. A return spring 58 is provided within the drum 56 and has one end fixed to the shaft 57 and the other end fixed to the drum 56. Reference numeral 59 denotes a rotation stopper that is integral with the shaft 57 and applies tension to the torsion coil spring 58 from the beginning to prevent the shaft 57 from rotating.

As shown in FIG. 4, an arm 61 having a pawl 61a is rotatably attached to the other end of the cam lever 27 by a shaft 60, and the pawl 61a engages with a ratchet 62 that is integrated with the carry rope winding drum 47. ing. A spring 63 biases the arm 61 counterclockwise. Reference numeral 64 denotes a reversal prevention lever that engages with the ratchet 62, is rotatably supported by a shaft 65 attached to the side plate 5a, and is biased clockwise by a spring 66. This spring 66 is actually built into the bearing cover 65a of the shaft 65.

In the above configuration, when the first clutch lever 19 is disengaged by the first clutch release lever 15 and the cam lever 27 is rotated clockwise by the cam 26, the claw 61a of the arm 61 is engaged. The ratchet 62 is moved from the pawl 62a of the ratchet 62 to the engagement position with the adjacent pawl 62b. When the cam 26 and the cam lever 27 are disengaged and the cam lever 27 is rotated counterclockwise by the tension coil spring 29, the arm 61
7, the claw 61a at the tip thereof engages the claw 62b of the ratchet 62, and the ratchet 62
1 pitch clockwise. Reverse prevention lever 64
It resists the spring 66, climbs over the tip of the adjacent claw, and engages with that claw. The rotation of the ratchet 62 causes the carry rope 49 to be wound around the drum 47, sending the number carriage 44 to the left along the shaft 46 and moving the number wheel 1 by one digit.

Due to the movement of the number chassis 44, the return rope 5
3 is rewound by rotating the drum 56. At this time, the spring 58 receives a force in a direction opposite to its winding direction, and is charged with a return force.

(d) Digit return (return) and paper feed mechanism (1st and 5th
(Figure) After completing the printing operation for the predetermined number of digits, the number wheel 1 is returned to its original position and the paper is fed. The mechanism will be explained below.

Reference numeral 67 denotes a second clutch release lever rotatably supported by a shaft 68 attached to the side plate 5b, and has a permanent magnet 69 at the bottom thereof. It is adsorbed like this. The tip of the second clutch release lever 67 is in contact with the tip of the second clutch lever 71. The second clutch lever 71
is rotatably attached to the holding plate 72 by a shaft 73 at its base, and is biased clockwise in FIG. There is. The holding plate 72 is rotatably supported by a rotating shaft 76 attached to the side plates 5a and 5b. The rotating shaft 76 has a gear 77 fixed to the numerical axle 3.
Power is transmitted through the gear 78 that meshes with the shaft 76, and the shaft 76 constantly rotates. A ratchet 79 is fixed to the rotating shaft 76 in correspondence with the pawl 71a at the center of the second clutch lever 71. The holding plate 72 has claws 72a on its circumferential surface, and is coaxially and integrally connected with a partially toothed gear 80 for paper feeding.
and a cam plate 81 (FIG. 6). One end of the hammer rotating shaft 12 comes into contact with the cam surface 81a of the cam plate 81. A cam 12 is attached to the other end of the hammer rotating shaft 12.
a is provided, and the upper end of the carry release lever 82 contacts the cam 12a. The lever 82 is rotatably supported by a shaft 83 attached to the side plate 5a, and its lower part protrudes from the claw 61a of the arm 61 of the carry mechanism and the arm 61 toward the reverse prevention lever 64, and a pin 84 that touches the side surface of the lever 64 has been brought into contact with.

A pair of paper feeding rubber rollers 85 and 86 are provided below the number wheel 1, its movement path, and the symbol wheel 2. One driving rubber roller 85 is supported by a rotating shaft 87 attached to the side plates 5a, 5b, and a gear 88 fixed to one end of the shaft 87 is intermittently engaged with the intermittent gear 80. The other driven rubber roller 86 is supported by a rotating shaft 89 attached to the side plates 5a, 5b. The shaft 89 is movable toward the driving rubber roller 85, and the driven rubber roller 86 is pressed against the driving rubber roller 85 by a spring 90. Reference numeral 91 denotes a pull-up spring for the second clutch release lever 67, which is actually built into the bearing cover 68a of the shaft 68. 92 is a return spring attached to the second clutch release lever 67;
93 is a stopper for the second clutch release lever 67 attached to the side plate 5b, and 94 is a pin for preventing excessive return movement of the second clutch release lever 67, which is fixed to the holding plate 72.

[Digit return]

In the above configuration, when the solenoid 70 is energized by the digit return signal, the attraction force of the permanent magnet 69 decreases, the second clutch release lever 67 is rotated clockwise in FIG. That's 93. Since the second clutch lever 71 is disengaged from the lever 67, it is pulled by the coil spring 75 and rotates clockwise, and the claw 71a of the second clutch lever 71 is rotated clockwise.
is engaged with the ratchet 79 rotating clockwise. This engagement rotates the holding plate 72 and the cam plate 81 integrated therewith. Due to the rotation of the cam plate 81, one end of the hammer rotation shaft 12 is rotated to the cam surface 81a.
from the lower part to the higher part, and the hammer rotating shaft 12 moves to the left in FIG. As a result of this movement, the carry release lever 82, which was in contact with the lower part of the cam 12a at the other end of the hammer rotating shaft, rides on the higher part, so the lever 82 rotates clockwise in FIG. Disengage the prevention lever 64 and ratchet 62.

As mentioned above, since the return spring 58 is stored with a return force in the winding direction, the return force causes the winding drum 56 to wind up the return rope 53.
This is to return the number wheel 1 to its original position.

[Paper feed]

When the holding plate 72 rotates during the above-mentioned digit return, the partially toothed gear 80 rotates together with the holding plate 72, and the gear 88 engages with the partially toothed gear 80, causing the drive rubber roller 85 to rotate. As the driving rubber roller 85 rotates, the driven rubber roller 86 also rotates, and the printed paper P between the rollers 85 and 86 is sent upward by a length corresponding to the gear portion of the partially toothed gear 80.

The respective return operations of disengagement of the second clutch lever 71 and the ratchet 79 due to the engagement between the pawl 72a of the holding plate 72 and the return spring 92 and reconnection with the second clutch release lever 67 are the same as those described for the printing mechanism. It's the same.

(e) Hammer switching mechanism (Figs. 1, 6, and 7) Although not shown in Fig. 1, as shown in Figs. 6 and 7, a notch 12b is formed on the cam 12a side of the hammer rotation shaft 12. ing. When switching the hammer, a lever 95 that engages with the notch 12b is rotatably supported by a shaft 96 attached to the side plate 5a, and its lower part is reversed by a tension coil spring 98 whose one end is fixed to the shaft 97 of the side plate 5a. biased clockwise. Further, the lower end of the lever 95 is located within the rotation locus of the cam 26 of the printing mechanism, as shown in FIG. A tension coil spring 99 for returning the hammer rotation shaft is provided between one stepped portion of the number printing hammer 10 and the pin 33b on the cam side of the hammer rotation shaft 12.

As described in the above (d) digit return operation, the holding plate 72 and the cam plate 81 are rotated by the operation of the second clutch release lever 67, and the hammer rotating shaft 12 is moved to the cam surface 81.
When it rides on the high part of a, the hammer rotation shaft 12
Move to the left in the diagram. Due to this movement of the hammer rotation shaft 12, the lever 95 that was in contact with the vicinity of the edge of the notch 12b engages with the notch 12b, thereby stopping the axial movement of the hammer rotation shaft 12. At the same time, the pins 33b and 33c on the hammer rotation shaft 12 move, and the number printing pin 33b is positioned corresponding to the recess 10c of the stepped portion of the hammer 10, and the symbol printing pin 33c is positioned on the hammer 11. It is located corresponding to the convex part 11b of the stepped part.

In the above state, the above is indicated by the symbol printing signal.
When the printing mechanism shown in (a) operates, the pin 33c pushes the convex portion 11b of the symbol printing hammer 11, presses the hammer 11 against the symbol wheel 2, and performs a printing operation.
As described above, the number printing pin 33b also rotates, but its movement is permitted by the recess 10c of the hammer 10, so the number printing hammer 10 does not operate.

After the above symbol printing operation, the lower end of the lever 95 is pushed by the cam 26 of the printing mechanism, and when the lever 95 rotates clockwise against the tension coil spring 98, the lever 95 and the notch 12b of the hammer rotation shaft 12 is disengaged. The hammer rotating shaft 12 is pulled to the right in FIG. 1 by the tension coil spring 99, and one end thereof comes into contact with the lower part of the cam surface of the cam plate 81, returning it to a state where numbers can be printed.

In FIG. 1, 100 and 101 are mechanisms for detecting numbers, etc. to be printed on the number wheel 1 and the symbol wheel 2;
2,103 is a mechanism for detecting a motor stop signal.

FIGS. 8 and 9 show the operating order of the printer of the present invention, in which a symbol printing operation is performed first after motor drive is started, and then the operation is switched to a numeric printing operation.

As described above, the present invention uses a single highly efficient DC motor to obtain the driving force for the rotation and digit direction movement of the character wheel, the printing operation of the printing hammer, and the intermittent feeding of the printing paper. The cost ratio of the motor to the printer can be reduced compared to the case of using a pulse motor. In addition, the power transmission system of the above DC motor, printing, carrying,
Since the paper feed/return mechanism is connected by two mechanically interlocking clutch mechanisms, there is no need for an expensive and space-consuming electromagnetic clutch. You will get a serial printer. Furthermore, the movement of the printing hammer during the printing operation causes the printing hammer to come into pressure contact with the character wheel.In other words, the character wheel is stopped before the printing paper is pressed against the character wheel, so the character wheel remains rotating. It is possible to perform clear printing without causing problems such as character deviation and partial chipping due to timing mismatch between the printing hammer and the character wheel, which often occur when printing. Also, if the printing hammer is pressed against the character wheel while the character wheel is rotating, the printing paper will be pulled by the frictional force of the character wheel, causing the characters to be misaligned, so the printing paper must be strongly held by a pair of paper feeding rubber rollers. However, such a configuration increases the load on the operating system, and the motor is also susceptible to damage. In the present invention, since it is not necessary to adopt the above-mentioned configuration, the operation of the operating system is smooth and does not have any adverse effect on the motor. If the stopper 43 of the character wheel is configured with a leaf spring as described above as in the above embodiment, the stopper 43 will be closed after the printing operation.
returns to its original state while pushing the printing paper back, so when the character wheel starts rotating again, the printing paper is no longer in contact with the character wheel. Therefore, since the printed paper is not pulled upward by the frictional force of the character wheel, adjacent printed characters will not be misaligned when carry-up is performed.

As described above, the present invention is a small serial printer that can print clearly, and is effective in application to printers for battery-powered compact desktop electronic computers, output devices for battery-powered measuring instruments, and the like.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of an embodiment of the present invention, Fig. 2 is a front view of the printing mechanism, Fig. 3 is a front view of the character wheel stop mechanism, Fig. 4 is a front view of the carry mechanism, and Fig. 5. 6 is a plan view of the hammer switching mechanism, 7 is a side view thereof, and 8 is a rear view of the digit return and paper feed mechanism.
The figure is a block diagram showing the operating sequence, and FIG. 9 is a timing chart. 1 is the number wheel, 2 is the symbol wheel, 6 is the DC motor, 1
0 is a printing hammer for numbers, 11 is a printing hammer for symbols, 19 is a first clutch lever, and 67 is a second clutch lever.

Claims (1)

[Claims] 1. A character wheel that can rotate and move in the digit direction, a printing hammer corresponding to the character wheel, and a printing paper that is intermittently fed one line between the character wheel and the printing hammer. In a small serial printer, one DC motor is provided between the character wheel and the printing hammer, and one DC motor serves as a drive source for rotating and moving the character wheel in the digit direction, operating the printing hammer, and intermittent feeding of the printing paper. After stopping the character wheel using a spring pawl member that engages with the ratchet portion of the character wheel, and the power transmission system of the DC motor and the pawl member, the printing hammer is brought into pressure contact with the character wheel, and immediately after that, the character wheel is pressed. A mechanical first clutch mechanism provided between the mechanism for moving the character wheel in the direction of the digits, the power transmission system of the DC motor, and the character wheel that has been moved in the direction of the digits returns to a predetermined position, and the printing paper is A small serial printer comprising: a mechanical second clutch mechanism provided between a mechanism for intermittent feeding of rows; 2. In a small serial printer that has a character wheel that rotates and can move in the digit direction, a printing hammer corresponding to the character wheel, and printing paper that is intermittently fed for each line between the character wheel and the printing hammer, the above A second rotating character wheel that does not move in the digit direction is provided coaxially with a first rotating character wheel that is movable in the direction of the digits, and first and second rotating character wheels that are provided corresponding to the first and second rotating character wheels. a printing hammer; a DC motor serving as a drive source for rotating each rotating character wheel, moving the first rotating character wheel in the digit direction, operating each printing hammer, and intermittent feeding of printed paper; A spring pawl member is provided between the printing hammers and engages with the ratchet portion of the character wheel, and after the character wheel is stopped by the power transmission system of the DC motor and the pawl member, the printing hammer is moved to the character wheel. A first mechanical clutch mechanism is provided between the mechanism that presses the character wheel and immediately moves the character wheel in the direction of the digits, and the power transmission system of the DC motor and the character wheel that has been moved in the direction of the digits to a predetermined position. a second mechanical clutch mechanism provided between the second clutch mechanism and the mechanism for intermittently feeding the printed paper one line at a time; and the first or second printing hammer interlocked with the operation of the second clutch mechanism. A small serial printer having a switching mechanism for selectively operating the .