JPS6358706B2 - - Google Patents

Description

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

Recently, calculators have become more multi-functional and high-end.
It is desired that calculators with printers, which are smaller and lighter and can save calculation results as printed data, also be smaller and lighter. Therefore, it is desired that the built-in printer be small, lightweight, and consume low power. In addition, as a printer built into this type of electronic equipment used in general households, roll paper made of easily available and inexpensive 38 mm or 58 mm wide plain paper can be used, and the printed data is clear. Therefore, a matrix printing type is desired, and it is also expected to be inexpensive as it requires fewer driving sources.

[Schematic configuration]

FIG. 1 is a schematic diagram of the printer. A driving pulley 1 and a driven pulley 2 are arranged at a predetermined interval, and an endless type belt 3 is stretched between them. A worm 5 is attached to the rotating shaft of one DC motor 4 serving as a drive source, and the driving force of the motor 4 is transmitted to a main gear 8 via a first idle gear 6 and a second idle gear 7. The rotational force from the main gear 8 is transmitted to the drive pulley 1 via a spring clutch (described later), and a print/carry gear 9 can mesh with the main gear 8. ing.

One end of a printing/carrying shaft 10 is connected to the printing/carrying gear 9, and this printing/carrying shaft 10 is arranged between the driving pulley 1 and the driven pulley 2, and is parallel to the type belt 3. It extends to A hammer holder 11 is attached to the print/carry shaft 10 so as to be freely slidable in the axial direction, and includes and supports a hammer, a carry/paper feed cam, a rack release lever, etc., as will be described later. One end of a holder return spring 12 is connected to the hammer holder 11, and the other end of the spring 12 is fixed to a base (described later). Therefore, the hammer holder 11 is moved toward the driven pulley 2 by the tensile force of the holder return spring 12. It is always elastically biased toward the home position.

A rack 13 is arranged near the print/carry shaft 10 and parallel to it, so that the carry/paper feed cam built in the hammer holder 11 and the rack teeth of the rack 13 can mesh with each other as described later. There is. Behind the rack 13, a paper feed roller 14 and a flat guide plate 15 which also serves as a platen are arranged.
It is sent out from below and guided near the outside of the type belt 3. A selection lever 17 is operated by an electromagnetic solenoid 18 to switch and transmit the rotational force of the main gear 8 from the drive pulley 1 to the print/carry gear 9 at a predetermined timing. Reference numeral 19 denotes a position detecting section provided near the driven pulley 2, which detects a reference position for character selection and a character position. Reference numeral 20 denotes an ink roller that comes into contact with the type portion on the outer peripheral side of the type belt 3 to apply ink to the type surface.

The series of basic operations of this printer consists of type selection operation, printing/carrying operation, hammer holder return/paper feeding 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 related mechanisms will be explained in detail one by one, but first the configuration of the type belt 3 will be explained.

[Composition of type belt]

As shown in FIG. 3, the type belt 3 has an endless shape, and a large number of type parts 21 are individually provided along the circumferential direction at predetermined pitches on the outer circumferential side, and on the inner circumferential side, a large number of type parts 21 are individually provided along the circumferential direction. A large number of belt teeth 22 are provided at a predetermined pitch. Individual type section 2
1 and the belt tooth portion 22 are provided in pairs, that is, both are provided at the same pitch, and the type portion 21 (belt tooth portion 22) and the adjacent type portion 21
(belt tooth portion 22) are connected to each other by a thin connecting portion 23. These type portion 21, belt tooth portion 22, and connecting portion 23 are molded, for example, from synthetic rubber or synthetic resin with a low degree of polymerization, and the type belt 3 as a whole has appropriate flexibility, stretchability, and elasticity. .

As shown in FIG. 3, the total length of the type belt 3 is, for example, the first type group G1 and the second type group G2.
and the third type group G3. For example, the first type group G1 is
"+", "-", "×", "÷", memory symbol "M",
This is a group that collects typefaces that are printed less frequently than numerical symbols, such as the total mark "T", the subtotal symbol "◇", the count symbol "#", various alphanumeric symbols, or other special symbols. There is. On the other hand, the second type group G2 and the third
The type group G3 is a group of frequently printed characters such as numerical symbols, and both groups each have the same type, and the characters are arranged in the same order.
The details will be described later, but by arranging the characters on the character belt 3 as described above, it is possible to reduce the loss time for character selection as much as possible.

Type part 2 is located at the boundary between type groups G1 and G3.
1 and the belt teeth 22 are not provided, but instead a push-down piece 24 is attached.
The push-down piece 24 is molded from a relatively hard and slippery synthetic resin such as polyacetal resin, polyethylene resin, polyamide resin, etc., and has a substantially C-shaped side profile as shown in FIG. A notch 25 is formed in the middle for externally fitting onto the connecting portion 23 of the type belt 3. Note that the lower end of the push-down piece 24 protrudes slightly downward from the type section 21 and the belt tooth section 22 for a push-down function to be described later. On the other hand, push-down piece 2
As shown in FIG. 5, the front surface of the paper 4 is slightly recessed from the front surface of the printing section 21, that is, the printing surface, so that the push-down member 24 does not come into contact with the paper 16 during extrusion by a hammer 66, which will be described later. There is.

The type belt 3 is made as follows. That is, as shown in FIG. 6, a cylindrical type belt body 3a having the same diameter as the type belt 3 and a good width is made by molding, and this is molded to a predetermined width dimension (height dimension of the type belt 3). The sliced type belt 3b is obtained by cutting. Then, cut portions 25 of the push-down portions 24 are inserted into predetermined positions of each sliced type belt 3b.
(See Fig. 4) is expanded and fitted onto the outside to complete the type belt 3. Therefore, on the outer periphery of the type belt body 3a, type portions 21 having a predetermined character arrangement are repeatedly provided in the same arrangement in the width direction, while on the inner periphery, belt tooth portions 22 are provided in the width direction. It is formed into continuous ridges.

As explained in FIG. 1, the type belt 3 is stretched between the driving pulley 1 and the driven pulley 2,
Belt teeth 2 provided on the inner peripheral side of the type belt 3
2 mesh with the pulley teeth 26 (see FIG. 2) of the driving pulley 1 and the driven pulley 2, respectively, so that the type belt 3 is rotated reliably without slippage. As shown in Figure 1, the drive pulley 1
is rotated counterclockwise in the figure, and the type belt 3 is rotated in the direction of arrow A, so that the tension side is formed between the driven pulley 2 and the driving pulley 1 on the side facing the paper 16. Furthermore, the pulley shaft 27 of the driven pulley 2 has a code plate 28 (see Fig. 2), which will be described later.
is attached to the code plate 28, and contact pieces 29 for detecting the position of characters are brought into elastic contact with the code plate 28, so that braking is always applied to the driven pulley 2. Because of this, there is no slack on the side of the type belt 3 facing the paper 16, and even if there is some vibration, the paper 16
There is no large swing along the feeding direction of 6.
Therefore, the accuracy of the printing position when printing is high,
Moreover, even if the distance between the type belt 3 and the paper 16 becomes narrower as printers become smaller, the type portion 21 will not come into contact with the paper 16 unexpectedly. Next, the type selection mechanism will be explained.

[Type selection mechanism]

First, the drive mechanism for the type belt 3 will be explained mainly with reference to FIG. A base 30 made of hard synthetic resin has a substantially rectangular planar shape, and a motor mounting recess 31 is provided at the center of the front side of the base 30, in which the DC motor 4 is installed. On the left side of the motor mounting recess 31, a pin-shaped gear support shaft 32 and a cylindrical gear support cylinder 33 are integrally protruded from the base 30 at a predetermined interval. A first idle gear 6 is rotatably fitted onto the gear support shaft 32, and a second idle gear 7 is rotatably fitted onto the gear support cylinder 33. The first idle gear 6 is provided with a helical portion 34 that meshes with the worm 5 attached to the DC motor 4, and a spur tooth portion 35 that meshes with the second idle gear 7. on the other hand,
The second idle gear 7 is formed with a spur tooth portion 36 that meshes with the spur tooth portion 35 of the first idle gear 6 . Therefore, the first idle gear 6 is connected to the gear support shaft 32.
By fitting the second idle gear 7 into the gear support cylinder 33, the worm 5, the first idle gear 6, and the second idle gear 7 are meshed with each other.

A pin-shaped main gear support shaft 38 and an ink roller support shaft 39 are respectively provided upright at the rear of the gear support cylinder 33 .
The spring clutch 40 and the driving pulley 1 are supported on the ink roller support shaft 39, and the ink roller 20 is supported on the ink roller support shaft 39, respectively.

Figures 7 to 9 regarding the shape of the main gear 8
This will be explained using figures. 7 is a plan view of the main gear 8, FIG. 8 is a sectional view taken along the line I-I in FIG. 7, and FIG.
The figure is a view taken in the direction of the arrows in FIG. As shown in FIG. 8, the main gear 8 is arranged along its axial direction.
It has a spur tooth portion 41 that meshes with the spur tooth portion 36 of the second idle gear 7, a deformed bevel tooth portion 42 that meshes with the print/carry gear 9 at a predetermined timing, and a central cylindrical portion 43. There is. This deformed bevel tooth portion 4
2 is used to transmit power to the print/carry gear 9, so its shape etc. will be explained in the [Print/Carry Mechanism] section below. By fitting the main gear 8 onto the main gear support shaft 38, the main gear 8 meshes with the second idle gear 7, and the rotational driving force of the DC motor 4 is transmitted to the main gear via the worm 5, the first idle gear 6, and the second idle gear 7. The transmission is such that the gear 8 is rotationally driven in a constant direction, that is, counterclockwise in FIG. 1, at a constant speed.

A spring clutch 40 is interposed between the main gear 8 and the drive pulley 1 in order to transmit the rotational driving force of the main gear 8 to the drive pulley 1 or to interrupt the drive transmission.
As shown in FIG. 2, this spring clutch 40 is composed of a cylindrical drive arbor 44, a spring fixing tube 45, a type position selection ratchet 46, and a coil spring 47.

One lower end 47a of the coil spring 47 is inserted and locked into the inner circumference of the spring fixing tube 45,
On the other hand, the other end 47b on the upper side is inserted and locked into the inner circumference of the drive pulley 1. With the coil spring 47 tightly wound around the outer periphery of the drive arbor 44, the drive arbor 44 is passed through the center hole of the spring fixing ring 45 and the center hole of the ratchet 46 into the center recess of the drive pulley 1 (not shown). ), and the central cylindrical portion 43 of the main gear 8 is press-fitted into the inner peripheral portion of the drive arbor 44 so as to rotate integrally therewith.
In addition, a fan-shaped protrusion 48 formed on the inner circumference of the ratchet 46 engages with a fan-shaped recess (not shown) provided in the central recess of the drive pulley 1 (however,
A small gap corresponding to the so-called slack angle of the coil spring 47 is provided between the fan-shaped protrusion 48 and the fan-shaped recess in the rotation direction. The spring fixing tube 45, the ratchet 46, and the pulley 1 are tightly fitted so that they rotate together. Therefore, these three members and the main gear 8 are connected via the coil spring 47.

When the first pawl 50 of the selection lever 17 (described later) is not fitted into the teeth of the ratchet 46, the coil spring 47 is tightened and the main gear 8
and the driving pulley 1 rotate together. When the first pawl 50 of the selection lever 17 is fitted into the teeth of the ratchet 46 and the rotation of the ratchet 46 is prevented,
Immediately, the coil spring 47 loosens, and the rotational driving force of the main gear 8 is no longer transmitted to the drive pulley 1.

In order to select type, it is first necessary to detect the reference position of the type belt 3. Next, a mechanism for detecting this reference position will be described. As explained in FIG. 1, the position detection section 19 is provided near the driven pulley 2. As shown in FIG. 2, this position detection section 19 includes a spherical button 51, an elastic metal piece 52,
It is mainly composed of a code plate 28 and a contact piece block 53. The button 51 is made of metal or hard synthetic resin, and is shown in FIGS.
As shown in Figure 1, the pulley shaft 27 of the driven pulley 2
is inserted into a buttonhole 55 provided on the movement trajectory of the type belt 3 near the shaft hole 54 into which it is inserted. Since the tip of the elastic metal piece 52 is disposed below the button hole 55, the button 51 is supported by the elastic metal piece 52, and as shown in FIG. It protrudes slightly from the top surface. The base end of the elastic metal piece 52 is bent vertically upward to form the metal piece terminal 5.
6, and the base 30 as shown by the dotted line.
It penetrates from below to above the terminal array groove 57 formed in the terminal arrangement groove 57 .

The pulley shaft 27 of the driven pulley 2 is tightly fitted into the center hole of the code plate 28, so that the code plate 28 rotates together with the driven pulley 2. Although not shown, a conductive pattern having a predetermined shape is formed on the lower surface of the code plate 28 to detect the rotation angle of the driven pulley 2, in other words, the amount of movement of the type belt 3. This conductive pattern is
For example, it may be formed by printing or by laminating thin metal plates. The contact piece block 53 is composed of a reset contact piece 58, a bifurcated common contact piece 59, a set contact piece 60, and a mounting plate 61 to which these are attached by insert molding or the like. The base end of each contact piece 58, 59, 60 is bent vertically upward and connected to a reset terminal 62, a common terminal 63, and a set terminal 64.
, which protrudes upward from the terminal arrangement groove 57 in line with the metal piece terminal 56 as shown by the dotted line. Although not shown, each terminal 56, 62, 63, 64 is connected to the control section by a lead wire.

The tips of the reset contact piece 58, the shorter common contact piece 59, and the set contact piece 60 are in elastic contact with the lower surface of the code plate 28, and the longer common contact piece 59
are opposed to each other at a predetermined distance below the elastic metal piece 52, as shown in FIG.

As the drive pulley 1 rotates, the type belt 3 rotates in the direction of arrow A (see Figures 1 and 3).
While the push-down piece 24 attached to the type belt 3 does not pass over the button 51, the button 51 is supported by the elastic metal piece 52 and slightly protrudes from the base 30, as shown in FIG. 52 and the common contact piece 59 are separated. When the type belt 3 further rotates and the push-down piece 24 comes above the button 51, the upper surface of the push-down piece 24 comes into contact with the outer flange 65 of the driven pulley 2, and as a result, the eleventh
As shown in the figure, the button 51 is pressed down against the elasticity of the elastic metal piece 52, so that the elastic metal piece 52
contacts the common contact piece 59. This contact brings instantaneous electrical continuity between the metal piece terminal 56 and the common terminal 63, and from the signal it is possible to detect that the type belt 3 is currently at the reference position.

When the type belt 3 is at the standard position, the hammer 6
Since the distance of each type part 21 from the type part 21 (or the push-down piece 24) facing the type part 6 is known in advance, the amount of movement of the type belt 3, in other words, the driven pulley 2, is determined after the reference position is detected. By electrically counting signals of the rotation angle of
The type belt 3 can be rotated to a position opposite to the type belt 6.

Changes in the amount of movement of the type belt 3 due to carrying will be explained in detail with reference to FIGS. 12A and 12B. A in the figure is an explanatory view showing changes in the amount of movement of the type belt 3, and B in the figure is a front view of a portion of the paper 16 printed by this specific example.

First, the amount of movement of the type belt 3 when the hammer 66 is at the lowest digit as shown by the solid line will be described. The printing start signal causes the type belt 3 to rotate in a predetermined direction, and as shown in FIG. Assume that the reference position has been detected. At this time, the amount of movement l ₁ from the type part 21S facing the hammer 66 to the type part 21 of the symbol "+" to be printed at the lowest digit
is processed by the control unit, and the position detection unit 19 counts until the type belt 3 moves l ₁ , and the symbol “+” is detected.
Printing is performed when the type portion 21 having the shape faces the hammer 66.

The symbol printing operation ends at the lowest digit and the numerical value is subsequently printed, but if the symbol digit 67 and the numerical digit 68 are separated by one digit, as shown in Figure 12 (b). , the symbol digit 67 and the numerical digit 68 can be clearly distinguished and are very easy to see. Therefore, after printing the lowest digit, the next higher digit is not printed (details will be described later), and the hammer 66 is moved to the higher digit as shown by the dotted line in Figure 12A. . Therefore, if you want to print the numeric value "3" next, select the second type group G2 which is closest to the first type group G1 in the direction of rotation of the type belt 3 (which requires the least amount of movement of the type belt 3). The printed portion 21 with the numerical symbol "3" is selected. Then, from the printing part 21S facing the hammer 66 at the time of detecting the reference position, the second printing character group G
The control section calculates a moving amount _l2 which is the sum of the distance to the type part 21 selected in step 2 and the distance traveled by the hammer 66 by two digits from the lowest digit. Then, the position detection unit 19 counts the amount of movement of the type belt 3,
Printing is performed when the character portion 21 of the numerical symbol "3" faces the hammer 66.

Furthermore, when it is desired to print the numerical value "3" next, the printed character portion 21 with the numerical symbol "3" is selected from the third printed character group G3 closest to the second printed character group G2. Then, when detecting the reference position, the hammer 66
The amount of movement that is the sum of the distance from the printing section 21S that was facing the printing section 21S to the printing section 21 selected in the third printing group G3 and the distance that the hammer 66 moves by one digit.
_l3 is calculated in the same way, and the rotation of the type belt 3 and the printing operation are performed based on the calculation result.
In this way, until printing for one line is completed, the movement amount of the type belt 3 is adjusted each time a type is selected, based on the position of the printing part 21S, which was facing the hammer 66 when the reference position was detected. However, in reality, the amount of movement up to the selected character section 21 with the previous lower digit has already been calculated, so the amount of movement of the next digit is calculated by adding it thereto.

FIGS. 13 and 14 are diagrams showing other examples of the reference position detection means. In the reference position detection means shown in FIG. 13, when the type belt 3 is molded, a conductive movable contact portion 69 for detecting the reference position is integrally formed of conductive rubber or conductive synthetic resin. The movable contact portion 69 protrudes slightly downward from the type portion 21, the belt tooth portion 22, etc., and is designed to come into contact with two fixed contact pieces 70a and 70b provided under the rotation locus of the movable contact portion 69. It's summery. Therefore, when the conductive movable contact portion 69 passes over the fixed contact pieces 70a and 70b as the type belt 3 rotates, electrical continuity occurs between both contact pieces 70a and 70b, thereby causing the type character to The reference position of the belt 3 can be detected.

In the reference position detection means shown in FIG. 14, a conductive movable contact portion 69 for detecting the reference position is made of a metal piece, and is attached to a predetermined position on the type belt 3 by caulking. Similar to the reference position detection means explained in FIG. 13, the movable contact portion 69 protrudes slightly downward from the type portion 21 and the belt tooth portion 22, and the fixed contact pieces 70 are arranged at intervals.
a, 70b can be contacted.

In addition, a reflective or transmissive photo sensor may be provided near the type belt 3 to optically detect the reference position and/or the amount of movement of the type belt 3. Next, we will discuss the printing/carrying mechanism.

[Print/carry mechanism]

As shown in FIG. 2, a solenoid mounting base 71 is located on the left side of the motor mounting recess 31 on the near side of the base 30.
is provided protrudingly, and the electromagnetic solenoid 18 is fixed to the mounting base 71 via a mounting piece 72. The actuator 73 of the electromagnetic solenoid 18 has an L-shaped planar shape, and a through hole 74 is formed in a horizontal portion provided between a base end 73a and a free end 73b. On the other hand, an actuator support shaft 75 is protruded from the side of the gear support cylinder 33 of the base 30, and its upper small diameter portion is inserted into the through hole 74, so that the actuator 73 is moved in a predetermined position around this support shaft 75. It is designed to rotate at an angle. An actuator biasing spring 76 is loosely fitted into the lower large diameter portion of the actuator support shaft 75, one end 76a of which is attached to the edge of the base 30 as shown by the dotted line, and the other end 76b
is the proximal end 73 of the actuator 73 as shown by the dotted line.
a, respectively.

As shown in FIG. 2, a lever rotation shaft 77 extends below the selection lever 17.
is fitted into the central recess of the gear support cylinder 33. This selection lever 17 has a first pawl portion 50 that engages with the character position selection ratchet 46, as well as a
A second claw portion 78 that engages with the carry gear 9 and a vertical engagement groove 79 into which the free end 73b of the actuator 73 is inserted with some clearance are provided.

Next, regarding the shape of the printing/carry gear 9, the first
This will be explained using FIGS. 5 to 17. FIG. 15 is a front view of the printing/carry gear 9, FIG. 16 is a partially cut right side view thereof, and FIG. 17 is a rear view thereof. The printing/carrying gear 9 is provided with a front tooth section 80 and a rear tooth section 81 arranged one behind the other in the axial direction, and the front tooth section 80 has teeth partially (within a range of about 60 degrees from the center) in the circumferential direction. A toothless portion 82 in which no portion is formed is provided (see FIG. 15). On the other hand, the rear tooth section 81 is composed of one tooth section, and this is provided behind the toothless section 82 as shown in FIG. Although no other tooth portion is provided in the circumferential direction of the rear tooth portion 81, the rear tooth portion 8
A notch 83 into which the second claw portion 78 of the selection lever 17 fits is formed near the selection lever 17 . A shaft hole 84 with an oval-shaped front face is formed in the center along the axial direction, and a printing/carrying shaft 10 with an oval-shaped cross section is formed.
One end of the two is tightly fitted. Printing/
2 and 16 on the rear outer periphery of the carry gear 9.
As shown in the figure, a circumferential groove 85 is formed, and a bearing 86 provided in the base 30 is connected to the circumferential groove 85.
the other end of the printing/carrying shaft 10 into the bearing 8.
7, the print/carry shaft 10 is rotatably supported on the base 30.

As shown in FIG. 2, a spring support pin 88 is horizontally protruded diagonally below the bearing 86, and a gear biasing spring 89 is loosely fitted onto the spring support pin 88. That is, as shown in FIG. 18A, the gear biasing spring 89 is loosely fitted into the spring support pin 88, its base end 89a is in elastic contact with the end surface of the base 30, and its free end 89b is connected to the printing/carrying gear. It is in elastic contact with the cam portion 9a adjacent to the circumferential groove 85 of No.9.

This printing/carrying gear 9 is designed to mesh with a deformed bevel tooth portion 42 of the main gear 8 at a predetermined timing, and the deformed bevel tooth portion 42 has nine along the circumferential direction as shown in FIG. Radial grooves 90 are formed at equally divided positions, and teeth are provided on the inner peripheral side between the radial grooves 90.

Next, switching from drive transmission from main gear 8 to drive pulley 1 to drive transmission from main gear 8 to print/carry shaft 10 will be described. 18A and 18B and FIG. 19 show a state in which drive is transmitted from the main gear 8 to the drive pulley 1. That is, in this state, since the electromagnetic solenoid 18 is not energized, the base end 73a of the actuator 73 is pulled by the actuator biasing spring 76, as shown in FIG. As a result, the actuator 73 rotates clockwise around the actuator support shaft 75, and its free end 73b presses the engagement groove 79 of the selection lever 17 toward the front in the drawing. . Due to this pressing, the selection lever 17 is rotated counterclockwise about the lever rotation shaft 77, and as shown in FIG. 83, while the 19th
As shown in the figure, the first pawl 50 is spaced apart from the teeth of the character position selection ratchet 46.

18A and 18B show the printing/carry gear 9 in the same position. In FIG. 18B, the central cylindrical portion 43 of the main gear 8 is omitted in order to clearly show the state of the print/carry gear 9. That is, the second claw portion 7 of the selection lever 17
8 is fitted into the notch 83 of the print/carry gear 9, the missing tooth portion 82 of the print/carry gear 9
is opposed to the deformed bevel tooth portion 42, and the rear tooth portion 81
It does not fit into the radial groove 90 either. Therefore, the main gear 8 and the print/carry gear 9 have no engagement relationship, and as described above, the first claw portion 50 is separated from the character position selection ratchet 46, so the rotational driving force of the main gear 8 is spring clutch 40
The signal is transmitted to the drive pulley 1 via. In this way, the driving pulley 1 rotates in the direction of arrow B in the same way as the main gear 8, thereby moving the type belt 3, and detecting the reference position and selecting type based on it as described above. .

A command is issued from the control unit to select a specified type portion 21, and based on the command, the electromagnetic solenoid 18 is activated.
is energized and excited. With this excitation, as shown in FIG. 20, the base end 73a side of the actuator 73 is attracted to the electromagnetic solenoid 18 against the elasticity of the actuator biasing spring 76, thereby causing the actuator 73 to move counterclockwise to the selection lever. 17 rotate clockwise. With this rotational movement, the second claw part 78 of the selection lever 17 separates from the cutout part 83 of the print/carry gear 9, and the first claw part 5
0 meshes with the teeth of the character position selection ratchet 46. This prevents the rotation of the ratchet 46, and the action of the spring clutch 40 cuts off the drive transmission to the drive pulley 1, so that the selected type portion 21 is held at a position facing the hammer 66.

The second claw part 78 is the notch part 8 of the printing/carry gear 9
3, the printing/carrying gear 9 is slightly rotated by the elasticity of the gear biasing spring 89 as shown by arrow C in FIG. 18A. Then, the rear tooth part 81
is fitted into the radial groove 90 of the main gear 8, and the rotation of the main gear 8 pushes the rear tooth portion 81 and continues to rotate.The front tooth portion 80 then meshes with the deformed bevel tooth portion 42, and the main gear 8 rotational driving force is printed/
It is transmitted to the print/carry shaft 10 via the carry gear 9 and rotates in the direction of arrow C.

As shown in FIGS. 2 and 21, the hammer holder 11, which is slidably attached to the print/carry shaft 10, has insertion holes 91, 91 on both rear side plates through which the print/carry shaft 10 can freely rotate. formed,
A hammer mounting portion 92 extends horizontally from the rear toward the front on the upper inner side thereof. A spring hanging pin 93 is protruded from the rear of one of the side plates, and a long groove 94 is cut horizontally in front of the spring hanging pin 93 facing toward the spring hanging pin 93. Lever support portions 95 cut into shapes are formed on both side plates diagonally below and in front of the long groove 94, and furthermore, a partition wall portion 96 is suspended in front of the hammer holder 11. As shown in FIG. 22, this partition wall portion 96 has a protrusion opening 97 in the middle thereof large enough to allow one of the selected type portions 21 to protrude, and the partition wall portion 96 is provided on both sides of the protrusion opening 97. Note that, as shown in FIG.
8, the type part 21 from the ejection opening 97
The protrusion is carried out smoothly.

A carry/paper feed cam 99 connected to the print/carry shaft 10 by a spline is built in below the hammer placement portion 92 of the hammer holder 11 . The cam 99 includes a hammer drive section 100 extending in one direction from the center toward the outer periphery, a carry cam section 102 having a single protrusion 101 on the outer periphery, and a return rack 13 for paper feeding. It consists of an elliptical rack rotation part 103 which is integrally formed by molding synthetic resin. FIG. 24 is a developed view of the cam surface of the carry cam portion 102, and shows the protrusion 1
01 is a circumferentially extending circumferential protrusion 101a that is provided over about half of the circumferential direction, and a spirally extending helical protrusion 101b that is provided over about the remaining half of the circumferential direction. These protrusions 101a and 101b are continuous.
The protrusions 101 are adapted to mesh with rack teeth 104 provided at equal intervals on one side of the rack 13.

The hammer 66 is placed on the hammer placement part 92 with the extrusion part 105 facing the partition wall part 96, and the convex part 106 projecting upward is slidably fitted into the guide groove 107 formed on the upper surface of the hammer holder 11. There is. A spring hook pin 108 is protruded from one side of the hammer 66, and as shown in FIG.
protrudes outward from the and hammer holder 1
A tension spring 109 is stretched between the spring hook pin 93 of No. 1 and the spring hook pin 108 of the hammer 66, and the hammer 66 is elastically biased in a direction away from the type belt 3 (backwards) by the tension spring 109. . A receiving portion 110 is provided below the spring hook pin 108, with which a hammer drive portion 100 of the carry/paper feed cam 99 comes into contact with rotation.

25 and 26 are diagrams for explaining the printing operation. FIG. 25 shows the state before printing, and FIG. 26 shows the state before printing.
The figures are diagrams each showing a printed state. In the state before printing, as shown in FIG. 25, the hammer 66 is pulled rearward by the tension spring 109, and is positioned by a stopper (not shown). Therefore, the type belt 3 (type part 21)
is located between the partition wall portion 96 of the hammer holder 11 and the extrusion portion 105 of the hammer 66, and is slightly separated from the extrusion portion 105. Further, the hammer driving section 100 faces downward and does not come into contact with the receiving section 110 of the hammer 66.

The print/carry shaft 10 rotates once in the direction of arrow C due to drive transmission from the main gear 8, but the printing operation is performed continuously in the first half of the rotation and the carry operation is performed continuously in the second half of the rotation. ing. In other words, printing/
When the carry shaft 10 rotates in the direction of arrow C, the carry/paper feed cam 9 spline-coupled thereto
9 also rotates together, but on the front half circumference, the circumferential protrusion 1
Since 01a is meshing with the easy tooth 104,
The carry/paper feed cam 99 (along with the hammer holder 11, hammer 66, etc.) is not moved and only makes half a turn on the spot. Halfway around the carry/paper feed cam 99, the hammer drive section 100 comes into contact with the receiving section 110 of the hammer 66 as shown in FIG. is pushed forward against the Selected type part 2 facing paper 16
1 is projected forward from its ejection opening 97 by the push-out of the hammer 66 and is pressed against the paper 16 to perform desired printing. Note that, as shown in FIG. 22, since partition wall portions 96 are provided on both sides of the projection opening 97, unnecessary printing such as side printing is not performed. Print/carry cam 9
9, the hammer drive unit 100 moves to the 29th position.
As shown in the figure, by moving upward from the horizontal position, the hammer 66 is pulled rearward by the tension spring 109, and the hammer 66 is moved upward from the type belt 3.
move away from During this reciprocating movement of the hammer 66, the hammer 66 is properly guided by the engagement between the hammer mounting portion 92, the convex portion 106, and the guide groove 107, and the engagement between the spring hook pin 108 and the long groove 94.

When the printing/carrying cam 99 subsequently rotates, the spiral protrusion 101b from earlier engages with the lock tooth 104, and as it rotates, it resists the elasticity of the hammer return spring 12 and moves the hammer holder 11, hammer 66, printing/digit The raising cam 99 and the like move toward the upper digit (to the left in FIG. 1) by an amount corresponding to one digit, thereby performing a carry.

In this way, by repeating the character selection, printing operation, and carry operation, one line is printed.

In FIG. 2, a rack receiving through hole 111 is bored diagonally below the bearing 86, into which a cylindrical portion 112 at one end of the rack 13 is rotatably inserted.
The cylindrical portion of the other end of the rack 13 is rotatably fitted into an arcuate rack receiving recess 114 provided diagonally below the bearing 87, thereby positioning the rack 13. A paper feed shaft 115 is provided at the bottom of the rack receiving through hole 111 and the rack receiving recess 114.
An arm 11 that rotatably supports both ends of the
6 paper guide wall 1 with two paper guide walls provided at a predetermined interval.
17 are erected.

FIGS. 30A and 30B are a partial front view showing the shape of the upper part of the paper guide wall 117 and a partial front view of a sheet of paper printed according to a specific example. As mentioned earlier, the distance between the symbol digit 67 on the lower digit side and the numerical digit 68 on the upper digit side is set at a predetermined distance, for example 1.
If they are separated by digits, the symbol digit 67 and the numerical digit 68 can be clearly distinguished and are very easy to see. Therefore, a printing notch 118 is provided on the upper part of the paper guide wall 117 for printing in a place corresponding to the symbol digit 67.
A mask portion 120 having a width corresponding to one digit is provided between the printing notch portion 119 for printing at a portion corresponding to the numerical digit 68. Then, while the hammer 66 moves from the symbol digit 67, which is the lowest digit, to the numerical digit 68, which is the higher digit, it stops at a position facing the mask portion 120, and the same operation as a normal printing operation is performed. Hammer 66
The printed part 21 pushed out by the mask part 1
20, no printing is done on the paper 16. Therefore, when selecting a type at this digit position, the type portion 21 slightly before the type portion 21 selected at the next higher digit is selected. Next, return the hammer holder.
The paper feeding mechanism will be explained.

[Hammer holder return/paper feed mechanism]

As mentioned above, once one line has been printed,
It is necessary to return the hammer holder 11 to its home position again to prepare for printing the next line. Although the explanation was omitted in the above [Printing/Carry Mechanism] section,
Lever support portions 95, 95 of the hammer holder 11
Both ends of the lock release lever 121 are rotatably supported on the mount. The lock release lever 121 is provided with a receiving pawl 122 that projects upward and a slide protrusion 123 that projects downward. As shown in FIGS. 31 and 32, the rack release lever 121 is disposed between the hammer 66 and the rack 13, and before the rack 13 is rotated, the catch claw 122 is as shown in FIG. It is located diagonally in front of the type belt 3 below. On the other hand, the slide protrusion 123 has a hook groove 1 formed on the upper surface of the rack 13 along its longitudinal direction.
24, and as the hammer holder 11 is transferred, the slide protrusion 123 slides within the hook groove 124.

FIG. 31 shows the state before starting the hammer holder return. In this state, the position of the push-down piece 24 is selected so as to face the hammer 66, and since the push-down piece 24 protrudes below the type belt 3, the upper end of the receiving claw 122 It is located slightly above the bottom edge of.
As in a normal printing operation, the hammer driving section 100 rotates in the direction of arrow C, thereby pushing the push-down piece 24 toward the paper 16 via the hammer 66. As the push-down piece 24 moves horizontally, the rack release lever 121 rotates in the direction of arrow D as shown in FIG. Since they are engaged, the rack 13 is rotated in the direction of arrow E as the rack release lever 121 is rotated. The rack 13 thus tilted in the direction of arrow E remains in the tilted state until it is rotated back to its original position by a rack rotating section 103, which will be described later. Then, the rack tooth 104 separates from the protrusion 101 of the print/carry cam 99, and the engagement between the rack 13 and the print/carry cam 99 is released. Then, the hammer holder 11 containing the hammer 66, print/carry cam 99, and rack release lever 121 starts to return to the home position side along the print/carry shaft 10 by the tensile force of the holder return spring 12. .

As shown in FIG. 2, on the right end of the rack 13, there is a two
Two chevron-shaped paper feed intermediate lever portions 125 are provided in a protruding manner. On the other hand, Figures 2, 25 and 2
As shown in FIG. 6, a substantially disc-shaped intermediate stopper portion 126 is integrally provided on the end face of the rack rotating portion 103 of the carry/paper feed cam 99, and at a predetermined position of the intermediate stopper portion 126, as shown in FIG. Rack 1
A fan-shaped cut-out portion 127 is formed to have a size through which the paper feed intermediate lever portion 125 of No. 3 is inserted. Therefore, when the hammer holder 11 returns to the home position side, the end surface of the paper feeding intermediate lever section 125 on the rack tooth 104 side comes into contact with the outer surface of the intermediate stopper section 126, and the movement of the hammer holder 11 is stopped. Since the hammer holder 11 is thus stopped at an intermediate position close to the home position, the easy rotation part 10 of the carry/paper feed cam 99
3 and the paper feed intermediate lever portion 125 of the rack 13 are at mutually shifted positions and do not face each other.

A paper feeding operation is performed in parallel with this hammer holder return operation, and this operation will be explained next. As shown in FIG. 2, an engagement pin 128 is provided on the opposite side of the rack 13 from the rack teeth 104, projecting parallel to the axial direction of the rack 13. A paper feed shaft 115 is arranged behind this rack 13 and parallel to it, and two rubber rings 12 are placed approximately on the left half of it at a predetermined interval.
A paper feed roller 14 having a roller 9 elastically fitted thereon is fixedly attached thereto. As shown in FIGS. 2 and 33, a driven side paper feed ratchet 130 is attached to the right end surface of the paper feed roller 14, and the paper feed shaft 11
The drive side paper feed ratchet 131 is rotatably supported on the drive side paper feed ratchet 131. As shown in FIG. 33, the drive side paper feed latch 131 is always urged in the direction of engagement with the driven side paper feed latch 130 by the elasticity of a ratchet urging spring 132 inserted between it and one arm 116. ing. As shown in FIGS. 2, 34, and 35, a side surface of the drive-side paper feed latch 131 partially protrudes, into which the engaging pin 128 of the rack 13 is fitted horizontally and rotatably. A pin groove 133 is provided. Further, as shown in FIG. 35, a driven roller 134 that rotates with the paper feed roller 14 is arranged diagonally above the paper feed roller 14, and the paper 16 is held between the paper feed roller 14 and the driven roller 134. .

FIG. 34 shows the state before paper feeding is started. In this state, type selection or printing/
This means that a carry operation is being performed, and the rack 13 and the carry/paper feed cam 99 are engaged.

As mentioned above, the third
When the rack 13 rotates in the direction of arrow E as shown by the solid line in FIG. It rotates by a predetermined angle in the direction of arrow F. In this rotation in the direction of arrow F, the drive side paper feed latch 131 and the driven side paper feed latch 130 have tooth shapes that do not mesh with each other, so that when the rack 13 is completely fallen down, the drive side paper feed latch 131 and the driven side paper feed latch 130 are rotated as shown in FIG. The pin groove 133 of the side paper feed ratchet 131 is stopped with the pin groove 133 facing slightly diagonally upward, and is in a standby state for paper feeding.

On the other hand, when the rack 13 rotates, the rack teeth 104 of the rack 13 disengage from the carry/paper feed cam 99, so the holder return spring 12 described above
With this tensile force, the hammer holder 11 quickly returns to its home position. Note that when the hammer holder 11 returns to the home position from the lower digit, the hammer holder 11 reaches near the home position during the remaining 3/4 rotation of the carry/paper feed cam 99; During the rotation of the paper feed cam 99, the intermediate stopper portion 126 of the carry/paper feed cam 99 comes into contact with the side surface of the paper feed intermediate lever portion 125 of the rack 13, and the rack rotating portion 10
Since the position of the paper feeding intermediate lever section 125 is shifted from that of the paper feed intermediate lever section 125, the rack 13 is not scraped up by the rack rotating section 103.
The fallen state of the rack 13 and the standby state of the drive-side paper feed ratchet 131 shown in the figure are maintained as they are. Then, the carry/paper feed cam 99 is set to 1.
When the rotation is completed, the fan-shaped cutout portion 127 of the intermediate stopper portion 126 closes the paper feed intermediate lever portion 1 of the rack 13.
25, and only then can the hammer holder 11 completely return to its home position.

As mentioned above, when the print/carry shaft 10 completes one revolution for the hammer holder return (at this time, the electromagnetic solenoid 18 is already in the de-energized state), the tensile force of the actuator biasing spring 76 As shown in FIG.
This causes the print/carry gear 9 to
(Print/carry shaft 10) is prevented from rotating and becomes stationary.

At the same time, the first pawl 50 of the selection lever 17 is disengaged from the teeth of the type position selection ratchet 46, and the rotational driving force of the main gear 8 is transmitted to the drive pulley 1, and the type belt 3 is rotated. Rotate. Note that during this rotation of the type belt 3, the rack teeth 104 of the rack 13 are disengaged from the carry/paper feed cam 99, so there is sufficient time for the hammer holder return as described above. become. Next, the position of the type belt 3 is selected so that the push-down piece 24 faces the hammer 66, and the electromagnetic solenoid 18 is energized at the position where the push-down piece 24 faces the hammer 66, and the same process as described above is carried out. When the print/carry shaft 10 rotates approximately 1/4 turn, the push-down piece 24 is pushed out by the hammer 66 as shown in FIG. The difference from the hammer holder return operation is that the rack 13 has fallen down and the drive-side paper feed ratchet 131 is in a paper feed standby state, so the push-down piece 24 simply moves back and forth. On the other hand, in this case, the holder return spring 12
Since the hammer holder 11 is moved by the tensile force of ) is possible, and then the carry/paper feed cam 9
9 rotates, the rack rotation part 103 hits the paper feed intermediate lever part 125, and the fallen rack 13 is moved in the direction of arrow G as shown by the dotted line in FIG. 35 via the paper feed intermediate lever part 125. Rotate to. With this rotation, the rack 13 returns to its original position, and the rack teeth 104 engage with the protrusions 101 of the carry/paper feed cam 99, and as the rack 13 rotates, the drive side paper feed latch 131 moves in the direction of arrow H. Rotate to. Since the driving side paper feed latch 131 and the driven side paper feed latch 130 have tooth shapes that mesh with each other when rotating in the direction of arrow H, the paper feed roller 14 also rotates in the direction of arrow H. and thereby form 16
is pushed out in the direction of arrow I, and the paper is fed by an amount equivalent to half a line.

When the carry/paper feed cam 99 rotates once, the transmission of the driving force is switched by the selection lever 17.
The type belt 3 is rotated and the position is selected so that the push-down piece 24 faces the hammer 66 again.
While the carry/paper feed cam 99 rotates once, the rack 13 reciprocates in the directions of arrows E and G as shown in FIG. 1
4) is rotated in the direction of arrow F to enter the paper feeding standby state, and as it continues to be rotated in the direction of arrow H, the paper 16 is pushed out in the direction of arrow I, and an amount equivalent to the remaining half line is pushed out. Paper is fed.

In this embodiment, the paper feed roller 14 is rotated twice to feed the paper by an amount equivalent to one line, but for example, by increasing the diameter of the paper feed roller 14, one rotation is equivalent to one line. It is also possible to feed paper by the same amount.

As shown in FIG. 35, the paper 16 is sent out by the cooperation of the paper feed roller 14 and the driven roller 134.
is pushed up through the gap between the guide plate 15 and the paper guide wall 117 so that the area to be printed next faces the hammer 66, as shown in FIG. 28, for example. As mentioned above, the paper guide wall 117 is attached to the base 3.
Although the guide plate 15 is formed integrally with the paper guide wall 117, as shown in FIG.
5, both ends of which are tightly fitted to each other, so that it is fixed so that it does not wobble. This guide plate 1
5 is made of a thick metal plate and also serves as a platen.

The design is such that the play of the carry/paper feed cam 99 relative to the print/carry shaft 10 is minimized.
Therefore, for example, when the printer is used at low temperatures, the hammer holder 11 does not return easily and takes time to return. In this printer, the type selection operation is performed after the return of the hammer holder 11 starts until the fallen rack 13 is lifted up, so there is plenty of time before the hammer holder 11 returns to its home position. be. Moreover, hammer holder 11 (carry/paper feed cam 99)
Since the mechanism is such that the rack 13 cannot be rotated to the position where it can be carried until the hammer holder 11 has completely returned to its home position, the rack 13 rotates while the hammer holder 11 is returning, and the rack 13 cannot be rotated to the position where it can be carried. 13 and the carry/paper feed cam 99 will not engage with each other to prevent the return operation of the hammer holder 11.

As described above, in the present invention, in order to perform carriage return, a rack is rotatably arranged, a rotational force transmission means is provided between the rack and the paper feed roller, and the rotational movement of the rack is utilized. The feature is that the paper feed roller is rotated.

With this configuration, the means for rotating the paper feed roller is simplified, and the printer can be made smaller and the cost can be reduced.

[Brief explanation of the drawing]

The figures are all for explaining the printer according to the embodiment of the present invention, and FIG. 1 is a schematic configuration diagram seen from a plane of the printer, FIG. 2 is an exploded perspective view of the printer, and FIG. 3 is a plane view of a type belt. 4 is a partially enlarged perspective view of the type belt, FIG. 5 is a partially enlarged plan view of the type belt, FIG. 6 is a plan explanatory view for explaining how to make the type belt, and FIG. The figure is a plan view of the main gear, FIG. 8 is a sectional view taken along the line II in FIG. 7, and FIG. 9 is a view taken in the direction of the arrow in FIG. 7.
Figures 10 and 11 are enlarged cross-sectional views of the reference position detection unit, Figure 12 A is an explanatory diagram showing changes in the amount of movement of the type belt due to carry, and Figure 12 B is a printed example. Partial front view of paper, 1st
3 and 14 are partially enlarged perspective views showing other examples of the reference position detection means, FIG. 15 is a front view of the printing/carry gear, and FIG. 16 is a partially cut away right side view thereof. , Fig. 17 is a rear view of the same, Fig. 18 A and B are explanatory views showing the arrangement of the printing/carry gear, Figs. 19 and 20 are explanatory views showing the operation of the selection lever, and Fig. 21 22 is a perspective view of the hammer holder, FIG. 22 is a partial front view of the hammer holder, and FIG.
Figure 3 is an enlarged cut-away plan view of the partition part in the hammer holder, Figure 24 is a front view of the carry/cam part, and Figure 2 is a front view of the carry/cam part.
Figure 5 is a side view of it, Figure 26 is a rear view of it,
Fig. 27 is a developed view of the cam surface, Figs. 28 and 29 are side views of the printing unit to explain the printing operation, Fig. 30A is a partial front view of the paper guide wall, and Fig. 30B is a partial front view of the paper guide wall. 31 and 32 are side views of the main parts for explaining the rotational movement of the rack, and FIG. 33 is a plan view of the main parts of the paper feeding section. , FIG. 34, and FIG. 35 are explanatory diagrams showing the paper feeding operation. 1... Drive side pulley, 2... Driven side pulley, 3
...Type belt, 4...DC motor, 8...Main gear, 9...Print/carry gear, 10...Print/carry shaft, 11...Hammer holder, 13...
Rack, 14... Paper feed roller, 15... Guide plate, 16... Paper, 17... Selection lever, 18...
...Electromagnetic solenoid, 19...Position detection section, 21...
...Print portion, 24...Pushing down piece, 28...Code plate, 29...Touch piece, 40...Spring clutch, 46...Ratchet for selecting print position, 50...
...First claw portion, 51...Button, 52...Elastic metal piece, 53...Touch piece block, 66...Hammer, 6
7... Symbol digit, 68... Numerical digit, 69... Movable contact portion, 70... Fixed contact piece, 73... Actuator, 78... Second claw portion, 96... Partition wall portion, 97...
...Protrusion opening, 99... Carry/paper feed cam, 100
... Hammer drive section, 101 ... Projection, 102 ...
Carry cam part, 103...Easy rotation part, 104
...Rack tooth, 115...Paper feed shaft, 117...
Paper guide wall, 118... Printing notch, 120...
...Mask part, 121...Rack release lever, 12
2... Receiving claw, 125... Paper feed intermediate lever section, 1
26... Intermediate stopper portion, 128... Engagement pin, 130... Driven side paper feed ratchet, 131
... Drive side paper feed ratchet, 134 ... Driven roller.

Claims (1)

[Claims] 1. A shifting cam body held in a carriage and selectively rotated intermittently; a rotating position where the rack is rotatable and engages with the shifting cam body; and a disengaged position where it cannot engage with the shifting cam body. When the rack is at the carry position, the carriage is moved in the carrying direction by the engagement of the carry cam body and the rack, and when printing for one line is completed, the carriage is moved to the carry direction. The printer is configured to rotate the carriage to the release position and return the carriage to the starting position by the force of a spring. A feed transmission body and a paper feed roller connected via a one-way clutch are provided,
A printer characterized in that a paper feed roller is moved by a predetermined amount in one direction by one reciprocating rotation of the rack.