JPH0126348B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to printers, and more particularly to serial printers.

Recent calculators have become more multi-functional and sophisticated,
It is desired that calculators with printers, which are smaller and lighter and can store calculation results as printed data, also be smaller and lighter. Therefore, it is desired that the printer built into this device be small and lightweight, and consume low power. Also, as a printer built into this type of electronic equipment used in general households, easily available and inexpensive 38mm width or 58mm printers are available.
Since roll paper made of wide plain paper can be used and the printed data is clear, a matrix printing type is desired, and it is also required that the number of driving sources is small and that it is inexpensive.

Various types of printers have been proposed in view of this point of view. Among these printers, there is a first type wheel that only prints the least significant digit (for example, for a function symbol), and a type wheel that prints the next and subsequent digits sequentially. a second one (for example for numerical symbols) which is carried on a carriage and transported;
Some printers are equipped with a type wheel. A serial printer equipped with the first type wheel and the second type wheel is
This has the advantage of reducing the number of driving sources and increasing the number of type types as a whole. In addition, in this type of printer, if a carry mechanism using a rack and a carry cam that meshes with the rack is adopted, the carry operation is reliable, and the carriage return by the spring can be performed simply by disengaging the rack from the carry cam. This makes carriage return control easier.

On the other hand, the type part is spirally arranged around the outer circumference of the type wheel, and is intermittently rotated by a Geneva gear mechanism, etc., and in synchronization with the intermittent rotation of the type wheel, the type part is moved by a predetermined amount (adjacent to the type wheel). If a printer is configured to advance by the amount corresponding to the digit direction misalignment pitch of the type section, the positioning is intermittently stopped and positioned one character at a time, so the positioning of the type wheel in the rotational direction is reliable, and the carry operation is It has the advantage of not requiring a control clutch for this purpose.

However, by combining the above-mentioned two configurations, i.e., the first type wheel is responsible for printing only the lowest digit, and the second type wheel is used to sequentially print the next and subsequent digits and is loaded onto a carriage and transported. , a structure in which the second type wheel is transported by a carry mechanism using a rack and a carry cam, and a type wheel is moved by a predetermined amount in synchronization with the intermittent rotation of the type wheel (equivalent to the shift pitch in the digit direction of the adjacent type part of the type wheel). ) If a configuration is adopted in which the carriage is moved, if the rack and the carry cam are engaged when printing for one line is started after the carriage returns, the second type wheel will be moved from the home position. Put it away. Therefore, it is necessary to engage the rack and carry cam after printing by the first type wheel, but if the rack and carry cam are simply engaged immediately after printing by the first type wheel, which type of type on the second type wheel There is a problem in that it is not possible to select the desired type because it is not known whether the section is at the rotational reference position.

The present invention was made in view of these points,
The purpose of this is to use the first type wheel, which only prints the least significant digit, and the second type wheel, which sequentially prints the next and subsequent digits and is loaded onto a carriage and transported.
It has a configuration in which the second type wheel is transported by a carry mechanism using a rack and carry cam, and the type wheel is moved by a predetermined amount in synchronization with the intermittent rotation of the type wheel (the digits of the adjacent type part of the type wheel are moved). The object of the present invention is to provide a printer which has the advantages of a configuration in which the shift is shifted by the amount corresponding to the direction shift pitch, and which can always select the correct type. An embodiment will be described below with reference to the drawings. In explaining this printer, we will first explain the general structure of the printer as a whole, and then explain the structure of the type section, type selection mechanism, print/carry mechanism, slider return mechanism, paper feed mechanism, etc.

[Schematic configuration of the entire printer]

FIG. 1 is a schematic diagram of the entire printer.
Two side plates 1a and 1b are arranged facing each other, and the side plate 1 is located at the lower part of the front side between the side plates 1a and 1b.
A guide rail portion 3 having a sliding groove 2 extending between a and 1b is formed integrally with the side plates 1a and 1b. Furthermore, a rack 4, a type shaft 5, a hammer 6, a paper feed shaft 7, etc. are installed between the side plates 1a and 1b from the front side, and above the paper feed shaft 7, a flat motor mounting part 8 is installed on the side plate 1a. , 1b.

The type shaft 5 has a first wheel 10 fitted with a first type ring 9 having a type part for symbol digits, and a second wheel 12 fitted with a second type ring 11 having a type part for numerical digits. are connected by splines.
A type position sensor 13 is attached to the left end of the type shaft 5 to detect the rotation angle of the type shaft 5 and select a type. The arm portion 15 of the slider 14 placed on the guide rail portion 3 is engaged with the second wheel 12 and the carry cam 42, and the second wheel 12 and slider 14 are connected to the type shaft 5.
and the guide rail 3 in the same way. An ink roller 16 is rotatably held on the slider 14, and the circumferential surface of the ink roller 16 comes into elastic contact with the peripheral printing portions of the first printing wheel 9 and the second printing wheel 2, and applies ink to the printing portions. I'm starting to do that. The right end of the type shaft 5 passes through the side plate 1b and a printing gear clutch 17 and is connected to a printing gear 18.

A paper feed roller 19 is fixed to the paper feed shaft 7, a paper feed gear 20 is connected to the right end of the paper feed shaft 7, and a paper feed control gear 21 is connected between the paper feed gear 20 and the printing gear 18. It is mediated.

A drive motor 22 is mounted and fixed on the motor mounting portion 8, and this single motor 22 performs a series of printing operations such as character selection, printing/carrying, slider return, and paper feeding. drive is made. The pinion gear 23 fixed to the drive shaft of the motor 22 is the idler gear 2
4 and a print gear drive body 25 to a print gear clutch 17 and a print gear 18 .

The right end of the rack 4 is connected to a rack control lever 26.
The printing gear clutch 17 is connected to the printing gear clutch 17 via the printing gear clutch 17. Further, a trigger solenoid 27 is attached to the outer surface of the side plate 1b, and its actuator 28
The tip thereof is adapted to engage with a printing gear clutch 17. One end of a return spring 29 is connected to the slider 14, and the tension of the spring 29 always elastically biases the carriage 14 and the second wheel 12 toward the home position side (side plate 1b side).

The paper 30 to be printed is inserted horizontally through the gap between the motor mounting section 8 and the paper guide plate 31 (see FIG. 35) disposed below it, and the paper 30 is inserted between the paper feed roller 19 and the paper feed driven roller 32. It is sent to the type wheels 9 and 11 in cooperation with the printing presses. and type wheel 9,1
1, since the selected type part is stationary at a position facing the paper 30, the paper 30 is moved by the action of the hammer 6.
is pressed against the type wheels 9 and 11 to print the selected type.

The series of basic operations of this printer consists of type selection operation, print/carry operation, slider return operation, and paper feed operation, and by sequentially repeating each of these operations, it is possible to print multiple lines. will be done. Each of the above-mentioned operations and the mechanisms related thereto will be explained in detail one by one, but first, the configuration of the type section will be explained.

[Composition of type section]

As described above, the type section is composed of the first type wheel 9 held by the first wheel 10 and the second type wheel 11 held by the second wheel 12. 1st
The outer periphery of the type wheel 9 is provided with print portions for each type of symbol to be printed on the symbol digit, and the print portions 33 are arranged at predetermined intervals on the same circumference, similar to a normal type wheel. It is provided.

As shown in FIGS. 2 and 3, the first wheel 10 has a type wheel fitting portion 3 into which the first type wheel 9 is fitted.
4, two opposing arcuate peripheral walls 35 provided on the side plate 1b side thereof, and two opposing locking legs 36 extending in the axial direction on the inside of the arcuate peripheral wall 35 in the same way. has been done. The type ring fitting part 34 is provided with a plurality of anti-rotation recesses 37 at predetermined intervals along the circumferential direction near the outer periphery thereof, while the recesses 37 are provided on the inner periphery of the first type ring 9. A plurality of anti-rotation convex portions 38 (see FIG. 3) that fit into the concave portions 37 are provided, and the engagement between the concave portions 37 and the convex portions 38 positions the first type ring 9 on the first wheel 10. Ru.

The printing gear 18 is provided with a cylindrical portion 39 extending in the axial direction, and a sliding recess 40 is formed in the vicinity of the tip thereof to face the cylindrical portion 39 as shown in FIG.
The vicinity of the tip portion of 9 is inserted from the outside to the inside of the side plate 1b. The bent end portion of the locking leg portion 36 of the first wheel 10 is slidably fitted into the sliding recess 40 and the side plate 1
The amount of movement of the first wheel 10 is regulated by b (details will be described later). A pressing spring 41 is inserted between the type wheel fitting part 34 of the first wheel 10 and the side plate 1b for urging the first wheel 10 (first type wheel 9) toward the upper digit. . Note that this pressing spring 41 uses a spring having a pressing force smaller than the tensile force of the return spring 29 (see FIG. 1).

The second wheel 12 is connected to the first wheel as shown in FIG.
Type ring fitting part 43 slightly wider than the wheel 10
, a small-diameter arm engagement groove 44 sequentially provided on the upper digit side, and a spur cam drive gear 45. A plurality of anti-rotation recesses 46 are provided near the outer periphery of the type ring fitting portion 43 at predetermined intervals along the circumferential direction. Note that the first wheel 10 and the second wheel
The central through holes of the wheel 12 are oval shaped to match the outer shape of the type shaft 5 so that they are splined to the type shaft 5.

Next, the second type wheel 11 held by the second wheel 12 will be explained using FIGS. 4 and 5. FIG. 4 is a perspective view of the second type wheel 11, and FIG. 5 is a developed view of the outer peripheral surface showing the arrangement of the type portions in the second type wheel 11. As shown in FIG. 4, the inner circumferential portion of the second type wheel 11 is
A plurality of anti-rotation protrusions 47 that fit into the anti-rotation recesses 46 of No. 2 are provided, and the recesses 46 and the protrusions 47
The second type wheel 11 is positioned on the second wheel 12 by the engagement of the second type wheel 11 .

On the outer periphery of the second type ring 11, numbers such as "0" to "9" and "・" should be printed in numerical digits.
The printed characters 33 such as "-" are arranged in a helical arrangement as shown in FIGS. 4 and 5. To explain in more detail using FIG. 5, the printed portion 33a of the number “0”
is provided at the lowest digit, and then the number "1" is printed at a constant pitch 33 toward the upper digit.
b, a printed part 33c with the number "2", a printed part 33d with the number "3", a printed part 33e with the number "4", a printed part 33f with the number "5", a printed part 33 with the number "6"
g, a printed portion 33h with the number “7”, a printed portion 33i with the number “8”, and a printed portion 33j with the number “9” are arranged in sequence, followed by a printed portion 33k with “・”, and the size of one printed portion 33. A character part 331 of "-" is provided through a slider return which does not have a character part 33 corresponding to the character part 33 and a blank part 48 for blanking for paper feeding. This last "-" printed part 331 is located on the most significant digit side in the second printed wheel 11, and the distance 1 between it and the number "0" printed part 33a located on the lowest digit side is 1. It is designed to be approximately the same size as the raised pitch P (12/13 x P). Therefore, this second type wheel 11 has 13 type portions including the blank portion 48, which are shifted by 1/13·P toward the upper digits with respect to the type portion 33a. The blank portion 48 is provided for performing slider return and paper feeding operations, and the operations will be explained in a later section. Next, the type selection mechanism will be explained.

[Type selection mechanism]

First, the drive mechanism for the type wheels 9 and 11 will be explained. As shown in FIG. 1, the driving force is transmitted from the motor 22 to the type shaft 5 via a pinion gear 23, an idler gear 24, a print gear drive body 25, and a print gear 18. The pinion gear 23 and the idler gear 24 are normal spur gears, and the end face of the pinion gear 23 has a disc portion 49 for preventing slippage.
are integrated.

The printing gear drive body 25 is for transmitting the driving force from the idler gear 24 to the printing gear clutch 17 and the printing gear 18, and as shown in FIGS. 2, 7, and 8, it is a printing gear having a substantially cylindrical shape. The idler gear 24 is disposed on the base side of the driving body 25.
A spur gear portion 50 is provided which meshes with the. One tooth groove of the spur gear portion 50 is different from the other tooth grooves and extends slightly in the axial direction, so that the printing gear clutch 1
An extension groove 51 is formed which engages with 7.

A crescent-shaped protrusion 52 is formed approximately in the center of the head of the printing gear drive body 25, and has an approximately crescent-shaped planar shape with a portion cut out into a fan shape and leaving a small arc-shaped circumferential surface. There is. A feed pin 53 having approximately the same height as the crescent-shaped projection 52 is provided on the opposite side of the small circumferential surface of the crescent-shaped projection 52 . Further, on the small circumferential surface side of the crescent-shaped protrusion 52, two anti-separation pins 54 are protruded in line-symmetrical positions, and the pins 54 are designed to be slightly lower than the feed pin 53. These crescent-shaped protrusions 52, feed pins 5
3 and the detachment prevention pin 54 engage with a portion of the printing gear 18. As shown in FIGS. 7 and 8, a central recess 55 is formed from the base side end surface of the printing gear drive body 25 toward the head, and this central recess 55 is protruded from a predetermined position on the outer surface of the side plate 1b. By fitting into a support pin (not shown),
A printing gear drive body 25 is rotatably supported. Note that the idler gear 24 also has a support pin (not shown) protruding from a predetermined position on the outer surface of the side plate 1b.
It is rotatably supported by.

The printing gear 18 is shown in FIGS. 2, 9, and 10.
As shown in the figure, an oval-shaped fitting hole 56 is formed in the center into which the right end of the type shaft 5 is firmly fitted, and the type shaft 5 rotates integrally with the print gear 18 due to this strong fit.
A printing gear drive body 25 is attached to the outer end of the printing gear 18.
A substantially disk-shaped rotationally driven portion 57 that engages with the head of the
is provided. As shown in FIG. 9, this rotationally driven portion 57 is provided with 13 deep grooves 58 extending from the outer periphery toward the center and 13 circular arc pieces 59 alternately along the circumferential direction. The type part 33 of the first type wheel 9 and the second type wheel 11 (both type wheels 9,
11 each includes one blank portion that does not directly participate in printing). The state of engagement between the head of the printing gear driving body 25 and this rotationally driven portion 57 will be explained later using FIG. 11.

On the axially inner side of the rotationally driven part 57, there is a cylindrical part 61 having one notch part 60 in the outer peripheral part (FIG. 9).
Then, a spur gear portion 62 is sequentially formed, and the cylindrical portion 39 is provided inside the spur gear portion 62.
This cylindrical portion 39 passes through the central through hole 63 of the printing gear clutch 17 and extends through the side plate 1 as shown in FIG.
It protrudes inside b.

FIG. 10 shows the axial positional relationship of the crescent-shaped protrusion 52, the feed pin 53, and the detachment prevention pin 54 with respect to the rotationally driven part 57 when the printing gear 18 and the printing gear driving body 25 are respectively installed at predetermined positions. is indicated by a dashed line. The crescent-shaped protrusion 52 and the feed pin 5 provided on the head of the rotationally driven part 57
3 is relatively long, so the crescent-shaped protrusion 5
The outer circumferential surface of the circular arc piece 59 is adapted to come into sliding contact with the outer circumferential concave surface 64 of the arcuate piece 59, and the feed pin 53 reaches the deep groove 58 and engages therewith. On the other hand, since the detachment prevention pin 54 is relatively short, it does not reach the deep groove 58, but its tip touches the inner surface 65 of the rotationally driven portion 57.
, and therefore the inner convex surface 6 of the arcuate piece 59
6, and is engageable with the tip of the arcuate piece 59. In addition, the crescent-shaped protrusion 5
2 and the detachment prevention pin 54 is slightly longer than the thickness of the arcuate piece 59 at its tip.

The printing gear 18 and the printing gear driving body 25 constitute a so-called Geneva mechanism. This will be explained using Figure 11 A, B, and C.

The motor 22 rotates in response to a print start signal from a control unit (not shown), which causes the printing gear drive body 25 to move in the direction of arrow A as shown in FIG. Rotate to . And the feed pin 53 is in the deep groove 5.
8, the feed pin 53 gradually enters the deep groove 58 as the printing gear driving body 25 rotates, and the printing gear 18 (rotation driven part 57)
Rotate in the direction of arrow B. At this time, the outer circumferential concave surface 64 of the arcuate piece 59 rotates while contacting the outer circumferential surface of the crescent-shaped protrusion 52. As shown in FIG. 11A, when the feed pin 53 enters the deep groove 58, one of the detachment prevention pins 54 is separated from the side edge of the arcuate piece 59 at the same time as the timing or a little later. The positional relationship with the prevention pin 54 is set.

As the feed pin 53 moves, the printing gear 8
The (rotated and driven portion 57) rotates in the direction of arrow B, and during this time the feed pin 53 once enters the deep side of the deep groove 58 and comes out again to the opening side. and the 11th
As shown in FIG.
Get inside 4. Continue printing gear drive body 2
5 rotates in the direction of arrow A, but since the feed pin 53 separates from the deep groove 58, the printing gear 8 (rotation driven portion 57) remains stopped. and the first
As shown in FIG. 1C, the crescent-shaped protrusion 52 rotates on the outside of the arcuate piece 59, and the two detachment prevention pins 54 successively rotate on the inside of the arcuate piece 59. When the printing gear driving body 25 rotates once from the state shown in FIG. .

In this way, at least two anti-separation pins 54 are installed at a predetermined interval on the opposite side of the feed pin 53.
If the structure is such that the detachment prevention pin 54 is engaged with the arcuate piece 59 immediately before the feed pin 53 enters the deep groove 58 and immediately before it comes out of the deep groove 58, the printing gear 18 and the printing gear The engagement relationship with the driving body 25 can be maintained reliably, and the printing gear 1
The intermittent drive characteristics of 8 are stabilized. This function of the detachment prevention pin 54 is particularly effective when the printing gear 18 and the printing gear driving body 25 become smaller in diameter as printers become smaller.

As mentioned above, the printing gear 18 is intermittently driven by the printing gear drive body 25, and during one rotation of the printing gear 18, rotation and rest are repeated approximately 13 times, and the printing gear 18 (type shaft 5) is at rest so that the type parts 33 of the first type wheel 9 and second type wheel 11 face the hammer 6.
1 and the printing gear 18 are set. As shown in FIG. 1, a type position sensor 13 is fixed to the left end of the type shaft 5, so that by detecting the rotation angle of the type shaft 5, in other words, the type wheels 9, 11, Type selection for the first type wheel 9 as well as for the second type wheel 11 can be carried out. Note that while this type selection is being performed,
Trigger solenoid 27 (see FIG. 1) is in a de-energized state. Next, the printing/carrying mechanism will be explained.

[Print/carry mechanism]

The printing gear clutch 17 interposed between the side plate 1b and the printing gear 18 has a central through hole 63 therein so that it rotates and stops at a predetermined timing regardless of whether the printing shaft 5 and the printing gear 18 rotate or stop.
The cylindrical portion 39 of the printing gear 18 is designed to have dimensions that do not allow a strong fit.

A hammer drive cam portion 67 protruding in one direction in the radial direction is provided at a position of the printing gear clutch 17 closest to the side plate 1b. A spur gear part 69 having a toothless part 68 on a part of the outer periphery on the axially outer side of the hammer drive cam part 67, a single gear part 71 having only one tooth part 70 in the circumferential direction, and rotation of the printing gear clutch 17. A locking cam portion 74 having a first locking end 72 and a second locking end 73 slightly lower than the first locking end 72 at a position facing the direction and slightly shifted in the circumferential direction, and a drop groove 75 at one position in the circumferential direction. A timing cylinder portion 76 having a timing cylinder portion 76 is sequentially provided.

The hammer driving cam portion 67 of the printing gear clutch 17 is always in elastic contact with the tip of a pressing arm 77 which is provided to protrude from the end of the hammer 6 on the side plate 1b side so as to extend substantially horizontally. On the front surface of the hammer 6, as shown in FIG. A cutout 81 located on the side is formed.
Support pin insertion holes 82 are formed at both upper ends of the hammer 6, and support pins 83 (FIGS. 15 and 16) protrude from the side plates 1a and 1b, respectively.
(see figure) into the insertion hole 82, the hammer 6 is rotatably supported by the side plates 1a and 1b. As shown in FIGS. 15 and 16, one end of a tension spring 84 is connected to the lower part of the hammer 6, and the other end is connected to the motor mounting portion 8 as shown in FIG. Therefore, the tension force of the tension spring 84 urges the hammer 6 to rotate around the support pin 83 so that the tip of the pressing arm 77 always comes into elastic contact with the cam surface of the hammer drive cam section 67. .

The spur gear portion 69 of the printing gear clutch 17 meshes with the spur gear portion 50 of the printing gear drive body 25.
Further, the tooth portion 70 of the single gear portion 71 is adapted to fit into the extension groove 51 of the printing gear drive body 25. The first locking end 72 of the locking cam portion 74 is adapted to engage one pawl portion of the rack control lever 26, which will be explained later in the [Slider Return Mechanism] section. . The second locking end 73 of the locking cam portion 74 is adapted to engage with the actuator 28 of the trigger solenoid 27, as shown in FIG. trigger solenoid 2
7 is attached to the outside of the side plate 1b with screws 85 as shown in the figure, and the actuator 28 is attached to the support shaft 8.
It is designed to rotate around 6. A biasing spring 87 is loosely fitted to the support shaft 86 and has both ends locked to the base end of the actuator 28 and the lower end of the side plate 1b, respectively.
8 is elastically biased in the direction of engagement with the second locking end 73 of the locking cam portion 74, as shown by the solid line.

The teeth of the paper feed control gear 21 are designed to fit into the drop groove 75 of the timing cylinder portion 76 located at the outermost side of the printing gear clutch 17, but this will be discussed later in the [Paper feed mechanism] section. I will explain.

The slider 14 is provided with an arm portion 15 extending toward the type shaft 5, and as shown in FIG. A recessed wheel connection portion 88 that allows rotation of 12 is provided,
A recessed carry cam holding portion 89 that rotatably holds the carry cam 42 is provided slightly in front of it. The main body side of the slider 14 is placed on the guide rail portion 3 having the sliding groove 2 as shown in FIG.
As shown in FIG. 18, on the lower surface of the main body of the 2, the outer edge 90 of the sliding groove 2 formed into a protrusion is slidably sandwiched.
Two clamping claws 91, 91 are provided protrudingly. One of the clamping claws 91 enters the sliding groove 2 and the outer edge 90
By sandwiching the slider 14, the slider 14 can move properly without falling off even when reciprocating on the guide rail portion 3 at high speed. At the top of the slider 14, there are ink roller support shafts 9 on both sides, as shown in FIG.
2 and 92 are provided in a protruding manner, and the ink roller 16 is rotatably supported thereon. One end of the return spring 29 is connected to the ink roller support shaft 92 on the side plate 1b side.

As shown in FIG. 2, the carry cam 42 has an arm engagement groove 93 in which the carry cam holding part 89 of the slider 14 fits, and a carry cam of the second wheel 12 along its axial direction. A carry cam driven gear 94 that meshes with the drive gear 45 and a carry screw portion 95 are integrally provided. In this embodiment, for space reasons, the number of teeth of the carry cam driven gear 94 is half the number of teeth of the carry cam drive gear 45, and the second wheel 12 (second type wheel 11) rotates once. During this time, the carry cam 42 rotates twice. The pitch _Ps of the screw teeth 96 provided on the outer periphery of the carry screw portion 95 is half of the carry pitch P, as shown in a developed view in FIG. Further, the direction in which the screw teeth 96 extend and the direction in which the letters are arranged from the letter part 33a to the letter part 331 are opposite to each other. The screw teeth 96 are designed to mesh with the rack teeth 97 of the rack 4, and the pitch of the rack teeth 97 is also half the carry pitch P. The rack teeth 97 are provided over a length corresponding to the movement range of the second type wheel 11, in other words, the area of numerical digits.

FIG. 20A is a diagram showing the positional relationship between the first type wheel 9 and the second type wheel 11 in the initial printing standby state before printing on the symbol digit. Paper 30 is interposed between type wheels 9, 11 and hammer 6. The type wheels 9, 11 are pushed back toward the home position by the return spring 29 (not shown), and as a result, the pressing spring 41 is in a compressed state, and the tip of the arcuate peripheral wall 35 of the first wheel 10 is pressed against the side plate. By abutting against the inner surface of 1b, the home positions of the first type wheel 9 and the second type wheel 11 are determined. At this time, as shown in the figure, the first
The type ring 9 faces the symbol digit hitting wall 78 of the hammer 6 via the paper 30, and the second type ring 11 faces the mask part 8.
It is facing 0.

As mentioned above, the printing gear drive body 25 and the printing gear 1
8, the first type wheel 9 and the second type wheel 11 are operated by power transmission from the motor 22.
is rotated intermittently, and first the first type wheel 9 is selected. The process from character selection to printing operation will be explained with reference to the timing chart of FIG. 22. As explained above, the first type wheel 9 is rotated intermittently so that each type part 33 thereof remains stationary for a short time in a position facing the paper 30 (hammer 6), and each time it rotates, the type A timing pulse is output by the position sensor 13. During operations other than printing, the toothless portion 68 of the printing gear clutch 17 faces the printing gear driving body 25 as shown in FIG. Although it is rotating in the A direction, the printing gear clutch 17 remains stationary.

As mentioned above, type selection is performed by counting pulse signals from the type position sensor 13 in the control unit, but in FIG. In this example, if the second
After the ``〓'' character part 33 comes to rest at a position facing the paper 30, the trigger solenoid 27 is energized at the same time as the next rotation starts. As shown in FIG. 17, before energizing the trigger solenoid 27,
The tip of the actuator 28 is the printing gear clutch 1
It engages with the second locking end 73 of the locking cam portion 74 at 7 to maintain the stationary state of the printing gear clutch 17. By energizing the trigger solenoid 27 at the aforementioned timing, the actuator 28 rotates as shown by the dotted line against the tensile force of the biasing spring 87, and the actuator 28 and the second locking end 73 are engaged with each other. It comes off.

When the printing gear clutch 17 is in a stationary state,
As shown in FIG. 15, the hammer drive cam part 6
As shown in FIG. 15, a printing gear clutch biasing spring 98 is in elastic contact with 7. As shown in FIG. Therefore, when the tip of the actuator 28 is disengaged from the second locking end 73, the printing gear clutch 17 is slightly rotated in the direction of arrow C by the pressing force of the printing gear clutch biasing spring 98. Along with this, as shown in FIG. 23, the extension groove 5 of the rotating printing gear drive body 25
The tooth portion 70 of the single gear portion 71 of the print gear clutch 17 is inserted into the print gear clutch 17 and rotated in the direction of arrow C by the rotational force of the print gear drive body 25. This time, the spur gear portion 69 of the printing gear clutch 17 meshes with the spur gear portion 50 of the printing gear drive body 25, and the printing gear drive body 25
The rotational driving force is transmitted to the printing gear clutch 17, which is subsequently rotated in the direction of arrow C.

Along with this rotation, the pressing arm 7 of the hammer 6
7 rides on the cam surface of the hammer drive cam portion 67 in the printing gear clutch 17. Subsequent rotation of the printing gear clutch 17 causes the hammer 6 to pivot about the support pin 83 in the direction of arrow D against the tension of the tension spring 84.
As shown in FIG. 16, when the tip of the pressing arm 77 rides on the top of the hammer drive cam section 67, the selected type section 33 is stationary at a position facing the paper 30; The paper 30 is pressed against the type part 33 by the symbol digit striking wall 78 of the hammer 6, and symbol digits are printed. When printing this symbol digit, the paper 30 is pressed by the numerical digit hitting wall 79.
The other parts of the paper are also pushed toward the type shaft 5, but as mentioned above, the second type ring 11 faces the mask portion 80 and the paper 30 is behind it, so the paper 30 is directly pushed to the second type type. There is no such thing as touching ring 11. As mentioned above, since the first type wheel 9 is intermittently rotated, when the first type wheel 9 is stationary, the paper 3
The timing of the type wheel 9 and the hammer 6 is such that the 0 is in contact with the type portion 33. This also applies to the second type wheel 11.

Since the trigger solenoid 27 is energized for only a short period of time, after energization, the tip of the actuator 28 is in elastic contact with the circumferential surface of the rotating locking cam portion 74 due to the restoring force of the urging spring 87. There will be a sliding contact. Then, the printing gear drive body 25
The printing gear clutch 17 rotates once during each rotation, and the printing gear clutch 17 rotates once.
When the actuator 28 rotates and returns to its original position, the tip of the actuator 28 falls into the second locking end 73 (see FIG. 17), and at the same time, the toothless portion 68 of the spur gear portion 69 falls as shown in FIG. is opposed to the printing gear drive body 25, power transmission is cut off, and it stands still.

As will be explained later, before the symbol digit is printed, the rack 4 is lying down and is not engaged with the carry cam 42. Then, when the printing gear clutch 17 completes one rotation for symbol digit printing, the rack 4
The rack 4 is returned so that the carry cam 42 and the carry cam 42 are engaged with each other, and the rack 4 is prepared for printing the subsequent numerical digits. Therefore, when selecting a type for symbol digit printing, as the type shaft 5 rotates, the second wheel 12 (second type wheel 1
1) and the carry cam 42 rotate together, but at this time, as mentioned above, the rack 4 and the carry cam 42 are not engaged, so the second wheel 12 is not carried up and the first wheel 10 (first type ring 9) remains pressed against the symbol digit position.

When symbol digit printing is completed, type shaft 5 continues to be 1.
As the carry cam 42 rotates, the carry cam 42 rotates twice while being engaged with the rack 4.
The slider 14 moves one digit toward the upper digit against the tensile force of the return spring 29. As a result, as shown in FIG.
It has moved to the position corresponding to the first numerical digit of 9. Further, as the second wheel 12 moves toward the upper digit, the first wheel 10 is similarly pushed toward the upper digit by the pressing force of the pressing spring 41, and as shown in FIG. The movement of the first wheel 10 is stopped when the stop leg 36 engages with the left end surface of the sliding recess 40 in the printing gear 18. At this stop position, the first type wheel 9 faces the mask portion 80 as shown in FIG. The type ring 9 is in this position and does not participate in printing due to the interposition of the mask section 80.

Next, a type is selected using the second type wheel 11, and the printing operation continues. Like the first type wheel 9, the second type wheel 11 is also rotated intermittently so that the type part 33 stands still for a short time when facing the paper 30, and based on this, a timing pulse is generated and sent to the trigger solenoid 27 in the printing operation. energization/excitation, printing gear clutch 17
rotation, operation of the hammer 6, type section 33 and paper 30
The timing of contact (printing), etc. is the same as in the case of the first type wheel 9 shown in FIG. 22, so a description thereof will be omitted.

Character selection and printing operations are performed during one rotation of the second type wheel 11. In other words, the second type wheel 11 rotates once every 1 digit is printed, and when that one rotation is completed, the second type wheel 11 It has already been moved to the next higher digit. That is, the carry cam 95 is engaged with the second wheel 12 holding the second type wheel 11,
While the second wheel 12 (second type wheel 11) rotates once, the carry cam 95 engages with the rack 4,
Rotate. As a result, against the tensile force of the return spring 29, the assembly of the second type wheel 11, second wheel 12, slider 14, ink roller 16, and carry cam 42 moves toward the upper digit by an amount equivalent to one digit. be done. As the carry cam 42 rotates, the position of the second type wheel 11 relative to the paper 30 gradually shifts toward the higher digits, so the type portion 33 is simply moved on the same circumference as the first type wheel 9. In the arranged one, the selected type part 33, in other words, the second type wheel 1
The printing position will be uneven due to the rotation angle of 1 (as the rotation angle increases, the printing position will move to the higher digit side),
The spacing between the next printing position and the next printing position becomes inconsistent. In order to prevent this from happening, the type layout of the second type theory 11 is taken into consideration. In FIG. 19, the arrow D indicates the rotation direction of the carry cam 95, and the screw teeth 96 are inclined as shown in the figure with respect to the rotation direction D, and are engaged with the rack teeth 97 of the rack 4 so as to move in the D direction. By continuously rotating the slider 14, the second type wheel 11, etc., the number of digits is gradually increased by one digit. On the other hand, the characters on the second type wheel 11 are arranged in an inclined manner as shown in FIG. The position of is gradually shifting toward the lower digits.

Therefore, as the carry cam 95 rotates, the second type wheel 11 is gradually raised, and correspondingly, the type portion 33 is gradually shifted toward the lower digits.
As a result, every type part 33 stands still so as to face a predetermined position on the paper 30, and the selected type part 3
3 is printed. In this way, printing and carry for one line are performed, and the next slider return and paper feed operation are performed.

[Slider return mechanism, paper feed mechanism]

24 and 25 show paper feed control gear 2.
1 is a top view and a front view of FIG. On the upper part of this paper feed control gear 21 (the side that comes to the side plate 1b side as shown in FIG. 2 when assembled), a three-toothed gear part 99 having three teeth in the circumferential direction is arranged at 180 degree intervals. It is provided. A toothless part 100 is formed on the tip side between the three-toothed gear part 99 and a toothless part 100 is formed on the root side between the two, and a toothless part 100 is formed on the same circumferential surface as the tip circle of the three-toothed gear part 99. A lock portion 101 is provided, and therefore the toothless portion 100 and the lock portion 101 are stepped.

Below this lock portion 101, two spring elastic contact claws 102 are provided at 180 degree intervals to protrude outward in the radial direction, and further below, two spring elastic contact claws 102 are provided at 180 degree intervals in the same manner.
Two lever rotation claws 103 are provided to protrude radially outward. 180 below the lever rotation claw 103
The first recessed tooth portion 10 consists of one tooth portion at a degree interval.
4 is provided, and the first recessed tooth portion 1 is provided below it.
Spur gear portions 106 having missing tooth portions 105 are formed at positions corresponding to 04, and further below the spur gear portions 106, second depressed tooth portions 107 each having one tooth portion at 180 degree intervals are formed. It is provided.

To briefly describe the engagement relationship between each part of this paper feed control gear 21 and other members, the three-toothed gear portion 99 is adapted to mesh with the paper feed gear 20 as shown in FIG. . As shown in FIG. 28, the tip of a paper feed control gear biasing spring 108 is in resilient contact with the spring resilient claw 102, thereby biasing it in the direction of arrow F. The base of the paper feed control gear biasing spring 108 is supported by a pin (not shown) protruding from the outer surface of the side plate 1b. The lever rotation pawl 103 engages with the rack control lever 26 as shown in FIGS. 29 and 30, and the first recessed tooth portion 104 is printed as shown in FIGS. 31 and 32. It is adapted to engage with a timing barrel 76 of gear clutch 17. Further, the spur gear portion 106 is the 33rd spur gear portion 106.
As shown in the figure, the second depressed tooth portion 107 is connected to the third depressed tooth portion 62 so as to mesh with the spur gear portion 62 of the printing gear 18.
As shown in FIGS. 4 and 35, it is adapted to engage with the cylindrical portion 61 of the printing gear 18. In addition,
Detailed operations and engagement relationships of each part will be described later.

As shown in FIG. 2, the rack control lever 26 has a spindle insertion hole 109 extending in the axial direction formed in the center thereof, and a spindle (not shown) provided on the side plate 1b is inserted into the spindle insertion hole 109. By inserting the
A rack control lever 26 is rotatably supported by the side plate 1b. On the tip side of the rack control lever 26,
A first claw portion 110 that is kicked down by the lever rotation claw 103 of the paper feed control gear 21 is provided. Slightly rearward in the axial direction from this first pawl portion 110, a second pawl portion 111, which the first locking end 72 of the printing gear clutch 17 abuts against, is protrudingly provided, and further axially rearward from this second pawl portion 110 is provided as described above. Return pawl 1 formed on arcuate peripheral wall 35 of first wheel 10
A third claw portion 113 is provided in a protruding manner, with which the third claw portion 112 abuts.

Further, as shown in FIG. 2, an engagement pin 114 extending parallel to the axial direction of the rack control lever 26 is integrally provided diagonally below the third claw portion 113. As shown in FIGS. 29 and 30, this engaging pin 114 is rotatably and slidably inserted into a pin groove 115 formed on the side surface of the rack 4.

Next, the slider return and paper feeding operations will be explained.

In order to return the slider 14 etc. to the home position after one line of printing is completed, the second
The blank portion 48 of the type wheel 11 is selected and a printing operation similar to that of the normal type portion 33 is performed, but during printing operations other than this blanking operation, as shown in FIGS. 32 and 35. As shown in FIG.
8 notches 60 at the same time. That is, the printing gear 18 is always intermittently rotated, while the printing gear clutch 17 rotates once during printing operation. When the depressed tooth portion 107 is in sliding contact with the circumferential surface of the cylindrical portion 61, or conversely, when the second depressed tooth portion 107 is opposed to the notch portion 60, the first depressed tooth portion 104 is in contact with the timing cylinder portion. It is in sliding contact with the circumferential surface of 76.

As shown in FIG. 28, the paper feed control gear 21 is biased to rotate in the direction of arrow F by the biasing spring 108, and as described above, the first depressed tooth portion 104 is attached to the timing cylinder portion 76. Rotation of the paper feed control gear 21 is prevented because it abuts against the circumferential surface or because the second depressed tooth portion 107 abuts against the circumferential surface of the cylindrical portion 61 .

On the other hand, the printing gear 18 before the slider return operation
The relationship between the spur gear portion 62 and the spur gear portion 106 of the paper feed control gear 21 is as shown in FIG.
Since the printing gear 18 faces the paper feeding control gear 21, the rotational driving force of the printing gear 18 is not transmitted to the paper feed control gear 21, and it remains stationary.

Further, the engagement relationship between the paper feed control gear 21 and the paper feed gear 20 before the slider return operation is the 26th
The state is as shown in the figure and FIG. 27. 2 and 26 before explaining this engagement relationship.
The shape of the paper feed gear 20 will be described using the drawings and FIG. 27. On the outer periphery of the paper feed gear 20,
The long tooth portion 116 of the same size as the axial length of the gear 20 is 2
1, short width tooth portion 1 shorter than the axial length of the paper feed gear 20;
17 are provided alternately. Before the slider return operation, this short width tooth portion 117 enters into the missing tooth portion 100 of the paper feed control gear 21, and the lock portion 101 of the paper feed control gear 21 is locked between the long width tooth portion 116 and the adjacent long width tooth portion 116. It's getting in between. Therefore, the paper feed control gear 21 and the paper feed gear 20 have no meshing relationship, and the paper feed gear 20 is locked by the lock portion 101 so as not to rotate, and the paper 30 is moved between the paper feed roller 19 and the paper feed driven roller 32. It is held in a stationary state by being held between the

When performing a slider return, the blank portion 48 of the second type wheel 11 is selected based on a return command signal from the control section, and blanking is performed. When this blank portion 48 is selected and faces the paper 30, the cutout portion 60 of the printing gear 18 faces the second recessed tooth portion 107 as shown in FIG. As shown in FIG.
Facing 04. Then, the paper feed control gear 21 does not lose its support, and the paper feed control gear biasing spring 108
(See FIG. 28), the first depressed tooth portion 10
4 falls into the falling groove 75, and the second falling tooth portion 107 falls into the notch 50, respectively. Due to the subsequent rotation of the printing gear clutch 17, the end face 1 of the drop groove 75
At 18, the first depressed tooth portion 104 is pushed, and the paper feed control gear 21 rotates slightly in the direction of arrow F. During this rotation, the printing gear 18 is intermittently rotated 360/13 degrees in the direction of arrow B from the position shown in FIG. The gear 21 rotates without any problem.

In this way, the printing gear 18 - paper feed control gear 21
With the AND condition of the printing gear clutch 17 and the paper feed control gear 21, the paper feed control gear 21 moves slightly toward the arrow F.
When rotated in the direction, the spur gear portion 106 of the paper feed control gear 21 shown in FIG. 21 continues to rotate in the direction of arrow F.

FIG. 29 is a diagram showing the positional relationship between the paper feed control gear 21, the rack control lever 26, and the rack 4 before the paper feed control gear 21 rotates in the F direction, in other words, before the slider returns. In this state, the tip of the first pawl portion 110 protruding from the rack control lever 26 is within the rotation locus of the lever rotation pawl 103 on the paper feed control gear 21. The rack teeth 97 of the rack 4 are in an upright position and are engaged with the screw teeth 96 of the carry cam 42.

As described above, when the paper feed control gear 21 rotates in the F direction, the lever rotation claw 10 rotates as shown in FIG.
3, the first pawl 11 of the easy control lever 26
0 is pressed and the tip of it is the lever rotating claw 103
The rack control lever 26 is rotated in the direction of arrow G until it exits the rotation locus. With this rotation, engagement pin 1
14 moves, thereby rotating the rack 4 in the direction of arrow H, and the rack teeth 97 fall and separate from the screw teeth 96.

When the engagement between the rack 4 and the carry cam 42 is released in this way, the second type wheel 11 and the second
Wheel 12, slider 14, ink roller 1
6. The assembly including the carry cam 42 is pulled back toward the home position by the tensile force of the return spring 29. The second wheel 12 is the first wheel 10
Before hitting the first wheel 10, the first wheel 10 is in the position shown in FIG. 21, but since the pressing force of the pressing spring 41 is smaller than the tension force of the return spring 29,
When the second wheel 12 hits the first wheel 10, the pressing spring 41 is compressed, thereby causing the first wheel 10 (the first
The type wheel 9) and the second wheel 12 (second type wheel 11) are each returned to their home positions, and the slider return operation is completed.

In addition, as shown in FIG. 26, the paper feed control gear 21
As a result of the rotation in the F direction, one of the teeth of the three-toothed gear portion 99 kicks the short width tooth portion 117 of the paper feed gear 20, which has been in the missing tooth portion 100, and moves the paper feed gear 20 slightly into the direction of the arrow. Go in the I direction. As a result, the three-tooth gear portion 99 and the long tooth portion 116 mesh with each other, and the paper feed gear 21 is subsequently rotated in the I direction. The paper feed control gear 21 rotates and its lock portion 10
1 fits between the long width tooth portion 116 and the next long width tooth portion 116 (rotation of 180 degrees), power transmission is interrupted, and during this time the paper feed gear 20 is rotated 90 degrees. Along with this rotation of the paper feed gear 20, the paper feed roller 19 is also rotated 90 degrees, and in cooperation with the paper feed driven roller 32, the paper 30 is fed by an amount corresponding to one digit.

FIG. 36 is a perspective view of essential parts of the paper feeding section. A horizontal portion 31a of a paper guide plate 31 made of a thin metal plate is placed below the motor mounting portion 8 with a slight gap, and a vertical portion 31b provided on the front side of the paper guide plate 31 extends to the front of the hammer 6. . This vertical part 31b
The above-described mask portion 80 is integrally provided on the vertical portion 31b, and two pressing pieces 120 for regulating the movement of the paper feed driven roller 32 in the axial direction are integrally formed on the vertical portion 31b. Further, the driven roller support shaft 119 that supports the paper feed driven roller 32 has appropriate elasticity.
The paper feed driven roller 32 is held in a bent state so as to be pressed against the paper feed roller 19 side.

In this manner, the slider return and paper feed operations are performed, and the rack return operation is completed immediately after the symbol digit printing of the next line is completed. Next, this rack return operation will be explained using FIGS. 37 and 38. As mentioned above, when the rack control lever 26 rotates in the direction of arrow G as shown in FIG. 30 and stops during the slider return operation, the second claw portion 1 protruding from the rack control lever 26
As shown in FIG. 37, the tip of the first locking end 72 of the printing gear clutch 17 falls within the rotation locus of the first locking end 72 of the printing gear clutch 17. Then, when printing symbol digits on the next line, the printing gear clutch 17 rotates once, but in the middle of this rotation, the second pawl portion 111 is pushed by the first locking end 72, and the lock control is activated. The lever 26 is slightly rotated in the direction of arrow J. As the rack control lever 26 rotates, the rack 4 slightly rotates in the direction of arrow K. At this point, the rack tooth 97 comes close to the screw tooth 96 of the carry cam 42, but it does not yet mesh with it. in position. This state is shown in FIG. When the rack control lever 26 is rotated slightly in the direction of the arrow J in this way, the third claw portion 113 of the rack control lever 26 is now moved toward the first wheel 10, as shown in FIG.
It enters the rotation locus of the return claw 112 provided on the arcuate peripheral wall 35 of. While the first wheel 10 makes one rotation intermittently, the selection and printing operation of the type part 33 to be printed on the symbol digit is performed, and just before the completion of one rotation of the first wheel 10, the The third claw portion 113 is pushed by the return claw 112. As a result, the rack control lever 26 is further rotated in the J direction, and the rack 4 is further rotated in the K direction, so that the rack teeth 97 mesh with the screw teeth 96 of the carry cam 42. In this manner, the return operation of the rack is completed, and then the second type wheel 11 is carried up and removed from the mask portion 80.

The desired line is printed by sequentially repeating the operations from character selection to rack return operation described above.

Although one blank portion 48 is provided on the second type wheel 11 for slider return operation and paper feeding, it is also possible to provide an additional blank portion for simply blanking and carrying.

As mentioned above, the present invention provides a first type carrier and a second type carrier held on a type shaft by means of a spline connection.
a type carrier, a second type carrier carrying rack that reciprocates between a disengaged position and a return position by rotation, and a carry that is connected to the second type carrier and meshes with the rack teeth at the rack's return position. a cam, and a return means for returning the carried second type carrier to the home position by releasing the engagement between the carrying cam and the rack; After printing, the next digit and subsequent digits are sequentially printed by the second type carrier, and the second type is printed by the intermittent rotation of the type shaft when the carry cam and the rack are engaged. In a printer in which the carrier is transferred in the direction of upper digits, and the second type carrier is transferred by an amount equivalent to one digit per revolution of the second type carrier, during the return path from the disengaged position of the rack to the return position. An intermediate stop position is provided, and when moving from the disengaged position to the intermediate stop position, the rack and carry cam maintain a non-engaged state, and the first one of the first type carrier
The present invention is characterized in that the rack is rotated from an intermediate stop position to a return position as the rack rotates, and the rack and the carry cam are engaged with each other.

Therefore, even if the rotation of the rack releases the engagement with the carry cam and the second type carrier returns to the home position, and printing of the next line is started by selecting the type on the first type carrier, Since the rack is in the intermediate stop position and remains out of engagement with the carry cam, the second type carrier only rotates and is not transferred in the direction of the column. Moreover, when the first type carrier completes one rotation, the rack moves to the return position and engages with the carry cam, so the first
The second type carrier, which rotates in synchronization with the type carrier, always has a reference position in the rotational direction at a fixed position when the racks are first engaged, and correct printing is performed by always referring to this rotational reference. . That is, if the rack is not provided with an intermediate stop position and the rack is returned immediately after printing with the first type carrier,
Since the amount of rotation of the first type carrier is arbitrary depending on the selected symbol, the rotational direction position of the second type carrier at the time when the rack and carry cam start to engage is not known, and if this happens, the second type carrier is transferred in the column direction as it rotates, so that the printing by the second type carrier becomes random. The present invention solves this problem, and has the advantage of being able to reduce the number of driving sources in a serial printer provided with a first type carrier and a second type carrier, and increasing the number of types of type as a whole.
A printer that advances the type carrier one character at a time in synchronization with the intermittent rotation of the type carrier has the advantage that the positioning of the type carrier in the rotational direction is reliable and print quality is good, and By returning the rack from the intermediate stop position to the return position, it is possible to provide a printer that has advantages such as being able to shorten the return time of the rack.

[Brief explanation of drawings]

The figures are all for explaining a printer according to an embodiment of the present invention, and FIG. 1 is a schematic configuration diagram of the entire printer, FIG. 2 is an exploded perspective view of the main parts of the printer,
FIG. 3 is a sectional view showing the state of engagement between the first wheel and the printing gear, FIG. 4 is a perspective view of the second printing wheel, and FIG.
The figure is a developed view of the outer peripheral surface for explaining the arrangement of the type parts of the second type wheel, Figures 6, 7, and 8 are top, front, and bottom views of the printing gear drive body, and Figure 9. 10 is a top view of the printing gear and a partially sectional front view; FIGS. 11A, 1B, and 1C are explanatory views showing the engagement state of the printing gear drive body and the printing gear; FIG. 12; Figure 13 and 1st
Figure 4 is a left side view, front view, and right side view of the printing gear clutch, Figures 15 and 16 are explanatory diagrams showing the driving operation of the hammer, and Figure 17 is an explanation showing the engagement relationship between the trigger solenoid and the printing gear clutch. 18 are exploded sectional views of essential parts for explaining the engagement relationship between the guide rail part and the slider,
Fig. 19 is a developed view of the screw portion of the carry cam, Fig. 20 is an explanatory diagram showing the positional relationship between the first type wheel and the second type ring in the initial printing standby state, and Fig. 21 is the first numerical digit. An explanatory diagram showing the positional relationship between the first type wheel and the second type wheel in the state before printing, Figure 22 is a timing chart to explain the printing operation of the symbol digit, and Figure 23 is the print gear clutch and the print gear drive. 24 and 25 are top and front views of the paper feed control gear, and FIG. 26 is the relationship between the three-toothed gear portion and the paper feed gear in the paper feed control gear. FIG. 27 is a sectional view taken along the line X--X in FIG. 31 and 32 are explanatory diagrams showing the relationship between the first recessed tooth portion of the paper feed control gear and the timing cylinder portion of the printing gear clutch. , FIG. 33 is an explanatory diagram showing the relationship between the spur gear portion of the paper feed control gear and the spur gear portion of the printing gear.
4 and 35 are explanatory diagrams showing the relationship between the second recessed tooth portion of the paper feed control gear and the cylindrical portion of the printing gear, FIG. 36 is a perspective view of the main part of the paper feed section, and FIG. 37 and FIG. FIG. 38 is an explanatory diagram showing the rack return operation. 4... Rack, 5... Type wheel, 6... Hammer,
7...Paper feed shaft, 9...First type wheel, 10...First wheel, 11...Second type wheel, 12...Second type wheel
Wheel, 14...Slider, 17...Print gear clutch, 18...Print gear, 19...Paper feed roller, 20...Paper feed gear, 21...Paper feed control gear, 22...Motor, 25...Print Gear drive body, 26...Rack control lever, 27...Trigger solenoid, 29...Return spring, 30...
Paper, 33...Print section, 42...Carry cam, 4
8...Blank part, 57...Rotated driven part.

Claims (1)

[Claims] 1 A first type carrier and a second type carrier held on a type shaft by spline connection, a second type carrier carrying rack that reciprocates between a disengagement position and a return position by rotation, A carry cam is connected to the second type carrier and meshes with the rack teeth at the return position of the rack, and when the carry cam and the rack are disengaged, the second type carrier is moved to the home position. After printing on the lowest digit by the first type carrier, printing from the next digit onwards is performed sequentially by the second type carrier, and the carry cam and the rack The second type carrier is transferred in the direction of upper digits by intermittent rotation of the type shaft when the two types are engaged, and the second type carrier is transferred by an amount equivalent to one digit per rotation of the second type type carrier. In the printer, an intermediate stop position is provided in the middle of the return path from the disengaged position to the return position of the rack, and when the rack moves from the disengaged position to the intermediate stop position, the rack and carry cam maintain a non-engaged state. The present invention is characterized in that when the first type carrier completes its first rotation, the rack is rotated from the intermediate stop position to the return position, and the rack and the carry cam are engaged with each other. printer.