JPH0113436B2 - - 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 be smaller and lighter, and can save calculation results as printed data. Therefore, it is desired that the built-in printer be small, lightweight, and consume low power. In addition, for printers built into electronic devices 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.

Next, a serial printer according to an embodiment of the present invention will be explained in detail with reference to the drawings. First, the general configuration of the printer will be described.

[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 (not shown), and a print/carry gear 9 is meshed with the main gear 8. It's summery.

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 slidable in the axial direction, and a hammer and a carry cam are built in and supported therein 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 the base. Therefore, the hammer holder 11 is moved to the home position side near the driven pulley 2 by the tensile force of the holder return spring 12. is always elastically biased.

A rack 13 is arranged near and parallel to the print/carry shaft 10, so that the carry cam built in the hammer holder 11 and the rack teeth of the rack 13 can mesh with each other as described later. A paper feed roller 14 and a flat guide plate 15 that also serves as a platen are arranged behind the rack 13.
6 is sent out from below the paper feed roller 14 and guide plate 15 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 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 the mechanisms related thereto will be explained in sequence, 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 type belt 3 consists of two sets of type groups having the same type arrangement, and one set of type characters is composed of a symbol group MG, a number group FG, and a number group FG. As shown in FIG. 14, the symbol group MG is provided with 13 types of symbol type parts such as "+", "-", "x", etc. Each number group FG is "0"
Ten types of numeric characters from 9 to 9 are provided in the same arrangement. Therefore, one type group has a total of
There are 33 character type portions 21, and 66 type portions 21 are provided in the entire type belt. By providing a plurality of frequently used numeric groups FG in this manner, it is possible to reduce the loss time for character selection as much as possible.

As explained earlier, the type belt 3 is stretched between the driving pulley 1 and the driven pulley 2, and the belt teeth 22 provided on the inner circumferential side of the type belt 3 are connected to the driving pulley 1 and the driven pulley 2. They mesh with the pulley teeth 24 (see FIG. 2) of the pulley 2, so that the type belt 3 is rotated reliably without slipping. As shown in FIG. 1, the drive-side pulley 1 is rotated counterclockwise in the same figure, and the type belt 3 is rotated in the direction of arrow A, and the driven-side pulley 2 and the drive-side pulley 1 on the side facing the paper 16 are rotated. The tension side is between. For this reason, the side of the type belt 3 facing the paper 16 does not sag, and even if there is some vibration, the paper 16 does not swing significantly along the feeding direction. Therefore, the precision of the printing position when printing is high, and even if the distance between the type belt 3 and the paper 16 becomes narrower as printers become smaller, the type part 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. As described above, the driving force of the motor 4 is transmitted to the main gear 8 via the worm 5, the first idle gear 6, and the second idle gear 7. Furthermore, in order to transmit the driving force of the main gear 8 to the driving pulley 1 or to cut off the drive transmission, a known spring clutch (not shown) is installed between the main gear 8 and the driving pulley 1. is mediated. There is a code disk 25 under the main gear 8.
(see FIG. 2) are arranged coaxially, and eventually rotate synchronously with the drive pulley 1. The main gear 8 has a bevel gear shape, and is used for printing and
It is designed so that it can mesh with the carry gear 9.

The spring clutch can be set to a state where power can be transmitted (ON) to transmit power from the main gear 8 to the drive pulley 1, or the spring clutch can be set to a state where power cannot be transmitted (OFF) and the power can be transmitted from the drive side pulley 1. The selection lever 17 is used to switch the power transmission, such as stopping the rotation of the main gear 8 and instead transmitting the driving force of the main gear 8 to the print/carry gear 9 to rotate it. Turn on the spring clutch by operating this selection lever 17,
When the driving pulley 1 is rotated in the direction of arrow B as shown in FIG. 1, the type belt 3 is transferred in the direction of arrow A accordingly.

Although not shown, a conductive pattern having a predetermined pattern shape is formed on the lower surface of the code disk 25 to detect the rotation angle of the driving pulley 1, in other words, the amount of movement of the type belt 3. Furthermore, a plurality of contact groups consisting of a set contact, a reset contact, and a common contact are in elastic contact with this conductive pattern. These contact pieces are connected to a control section (not shown) by lead wires.

A code plate tooth part 26 is provided on the upper part of the code disc 25, and a spur gear part 28 of the sensor gear 27 is provided with the code plate tooth part 26.
are interlocking. On this spur gear part 28,
As shown in FIG. 4, a disk portion 29 having a diameter equal to the diameter of the tip of the tooth is provided, and a trigger groove portion 30 is formed at one location on the circumference from the spur gear portion 28 to the disk portion 29. There is. A cam disk portion 32 having a cam protrusion 31 at one location on its outer circumference is provided below the spur gear portion 28 .

Code plate tooth portion 26 in the code disk 25
The number of teeth in the pulley tooth portion 2 of the driving pulley 1 is
The number of teeth is equal to 4. Further, the number of teeth of the spur gear portion 28 in the sensor gear 27 is equal to the total number of characters in one set of character groups (symbol group + number group + number group) on the type belt 3 . Therefore, while the sensor gear 27 rotates once, the type belt 3 rotates exactly half a rotation.

A control gear 33 is arranged next to the sensor gear 27, and its shape will be explained with reference to FIG. 5. A single gear portion 35 having one tooth portion 34 in the circumferential direction is provided at the top of the control gear 33.
A fitting hole 36 is bored in the center thereof.
A spur gear part 38 having a toothless part 37 near the part facing the tooth part 34 is provided below the one gear part 35, and this spur gear part 38 is connected to the sensor gear 2.
It is designed so that it can mesh with the spur gear portion 28 of No. 7. A locking portion 40 is provided below the spur gear portion 28 and has one locking groove 39 on the outer periphery on the side substantially opposite to the toothless portion 37 . A paper feed cam portion 41 having a slightly larger diameter than the locking portion 40 is provided below the locking portion 40, and two spiral tooth portions 42a and 42b are arranged on the outer periphery of the cam portion 41 in a crossed manner so as to face each other every half circumference. is formed. As shown in FIG.
A spring hook pin 41a is provided protruding from the lower surface of 1. The cam control gear 33 including the single gear portion 35, the spur gear portion 38, the locking portion 40, and the paper feed cam portion 41 is integrally formed by molding synthetic resin.

A reset plate 43 is arranged above the control gear 33, and by press-fitting a shaft 44 hanging down from the center of the lower surface of the reset plate 43 into the fitting hole 36 of the control gear 33, the reset plate 43 rotates together with the control gear 33. . A protrusion 45 is provided on the upper surface of the reset plate 43 near the outer periphery.

The locking groove 39 of the locking portion 40 of the control gear 33 is configured such that a claw portion 47 of a rotating lever 46 can be fitted therein. The rotating lever 46 has a claw portion 4.
In addition to 7, a cam surface abutting part 48 is provided protrudingly, and its tip end is always in elastic contact with the cam disk part 32 of the sensor gear 27, as shown in FIG. As shown in FIG.
6a is provided in a protruding manner, and a tension spring 78 is stretched between it and the spring hook pin 41a of the paper feed cam portion 41. The tension force of the tension spring 78 urges the control gear 33 and the rotation lever 46 to rotate in respective predetermined directions.

In order to select type, it is first necessary to detect the reference position of the type belt 3. In this embodiment, immediately after the rotation lever 46 is rotated by the cam protrusion 31 of the sensor gear 27 as the sensor gear 27 rotates, in other words, the claw portion 47 of the rotation lever 46
Immediately after the type belt 3 comes off the locking groove 39 of
The reference position of the type belt 3 is the position where the type part 21 of "6" in the second number group FG corresponds to a hammer (described later) in the home position. Like this type belt 3
When is at the reference position, the distance of each type part 21 from the type part 21 corresponding to the hammer is known in advance, so after the reference position is detected, the amount of movement of the type belt 3, in other words, the distance of the drive side pulley 1 is determined. By counting the rotation angle by pulse signals from the code disk 25, the type belt 3 can be rotated to a position where the type part 21, which is commanded by the control section, corresponds to the hammer. It should be noted that since the position of the hammer changes sequentially due to the carry, the desired type can be selected by counting the aforementioned pulse signals in consideration of the amount of movement of the hammer. Next, the printing/carrying mechanism will be explained.

[Print/carry mechanism]

A hammer holder 11 is held on the print/carry shaft 10 so as to be slidable in the axial direction thereof, and this hammer holder 11 has a shape as shown in FIG.
In other words, the print/carry axis 1 is placed at a predetermined position on both side plates.
Insertion holes 49, 49 through which the hammer 0 can freely rotate are formed, and a hammer mounting portion 50 extends horizontally from the rear toward the front inside the insertion holes 49, 49 above. A spring hanging pin 51 is protruded from the rear of one of the side plates, and a long groove 52 is cut horizontally in front of the spring hanging pin 51 facing the direction of the spring hanging pin 51. Hammer holder 11
A partition wall portion 53 is suspended from both sides of the front side, and an ejection opening 54 having a size that allows one type portion 21 to protrude is provided between the partition wall portions 53.

A hammer 55 is placed on the hammer rest 50,
An extrusion portion 56 provided at the tip thereof is placed so as to face the ejection opening 54 . A protrusion 57 is protruded from the upper surface of the rear end of the hammer 55, and is slidably fitted into a guide groove 58 formed on the upper surface of the hammer holder 11. A spring hook pin 59 is provided protruding from one side of the hammer 55, and this pin 59
is projected outward from the long groove 52 of the hammer holder 11. This spring hanging pin 59 and hammer holder 11
A tension spring (not shown) is stretched between the spring hanging pin 51 and the hammer 5 due to its tension.
5 is elastically biased in a direction away from the type belt 3 (backwards). Note that the type belt 3 is configured to pass inside the partition wall portion 53 of the hammer holder 11.

A carry cam 60 connected to the print/carry shaft 10 by a spline is built in below the hammer mounting portion 50 of the hammer holder 11 . This cam 60
, a hammer drive part 61 extending in one direction from the center toward the outer periphery, a carry cam part 63 having a single protrusion 62 on the outer periphery, and an elliptical rack rotation part for restoring the rack. It consists of 64. The hammer driving section 61 is adapted to come into contact with a receiving section 65 provided on the hammer 55 by rotation. FIG. 8 is a developed view of the cam surface of the carry cam portion 63. The protrusion 62 includes a circumferentially extending circumferential protrusion 62a provided over about half of the circumferential direction, and a spirally extending circumferential protrusion 62a provided over the remaining half of the circumferential direction. Spiral protrusion 62
b, and these protrusions 62a, 62b are continuous. The protrusions 62 are adapted to mesh with rack teeth 66 (see FIG. 2) provided at equal intervals on one side of the rack 13.

As shown in FIG. 9, the rack rotating portion 64 is adapted to abut against a return lever portion 67 provided at the end (home position side) of the rack 13 when rotated.

The rack 13 is arranged near the print/carry shaft 10 and parallel to it so as to be rotatable by a predetermined angle, and as the rack rotates, the rack teeth 66 mesh with the protrusion 62 of the carry cam 60, or the rack teeth 66 mesh with the protrusion 62 of the carry cam 60. It may be canceled. At the end of the rack 13 on the side where the return lever section 67 is not provided, a rotation preventing pawl section 68 and a tilting notch section 69 are formed. The rotation stopper claw 68 and the tilting notch 69 are adapted to engage with the protrusion 45 of the reset plate 43, as shown in FIGS. 10 and 11. In addition, the first
FIG. 1 is a sectional view seen from the opposite direction to FIG. 10.

As shown in FIG. 2, an elliptical lever push cam portion 70 is provided on one side of the print/carry gear 9.
is provided, and is always in elastic contact with the end surface of the vertical wall portion 72 of the gear clutch lever 71. Therefore, the printing/carrying gear 9 (lever pushing cam part 70)
When the gear clutch lever 71 rotates once in the direction of arrow C, the gear clutch lever 71 reciprocates once in the direction of arrow D.
The gear clutch lever 71 also has a reset portion 73.
is provided, which is adapted to abut against a protrusion 45 of the reset plate 43, as shown in FIG.

The hammer holder 11 is connected to the holder return spring 12
(See FIG. 1), when the type belt 3 is at the home position, the reference position of the type belt 3 is detected as explained in the previous section [Print character selection mechanism]. At this time, the rack 13 has fallen down as shown in FIG. Furthermore, although the reset plate 43 is biased to rotate in the direction of arrow E by a spring (not shown) attached to the control gear 33, the rack 13 falls down as shown in FIG. ), since its rotation stopper claw 68 locks the protrusion 45 of the reset plate 43, the reset plate 43 and the control gear 33 connected thereto are prevented from rotating.

Further, when the reference position is being detected, the toothless portion 37 of the control gear 33 faces the spur gear portion 28 of the sensor gear 27, as shown in FIG. 6A, and the two are not meshed. ing. Furthermore, at this time, the cam surface abutting portion 48 of the rotating lever 46 is connected to the sensor gear 2.
7 is in contact with the cam bottom 47 of the cam disk portion 32, and therefore the claw portion 47 of the rotating lever 46 enters the locking groove 39 of the control gear 33.

When the sensor gear 27 continues to rotate in the direction of arrow F and the cam surface abutting portion 48 of the rotary lever 46 rides on the cam protrusion 31 as shown in FIG.
At the same time, the rotating lever 46 rotates in the direction of arrow G, and the claw portion 47 of the rotating lever 46 comes out of the locking groove 39 of the control gear 33.

However, in the non-returning state shown in FIG. 10A, the rotation is stopped by the rotation stopper 68.
The control gear 33 and the reset plate 43 remain as they are without rotating. The reference position of the type belt 3 is set immediately after the sensor gear 27 rotates and the cam surface contact portion 48 of the rotary lever 46 falls from the cam protrusion 31, so after the reference position is detected, the type is selected. will be done. It should be noted that the selection of printed characters has been explained in the previous section, [Printed Character Selection Mechanism], so the explanation will be omitted here. Due to the depression of the cam surface abutting portion 48 described above, the rotating lever 46 rotates in the direction opposite to the direction of arrow G, and the claw portion 47 enters the locking groove 39 of the control gear 33 again.

Once the type is selected at the bottom line (home position), the printing operation continues.

13A and 13B are diagrams for explaining the printing operation, in which FIG. 13A shows the state before printing, and FIG. 13B shows the state after printing. In the state before printing, as shown in FIG. 13A, the hammer 55 is pulled rearward by a tension spring, and is positioned by a stopper (not shown).
Therefore, the type belt 3 (type portion 21) is located between the partition wall portion 53 of the hammer holder 11 and the extrusion portion 56 of the hammer 55, and is slightly separated from the extrusion portion 56.
Further, the hammer driving portion 61 faces downward and does not come into contact with the receiving portion 65 of the hammer 55.

The print/carry shaft 10 rotates once in the direction of arrow C due to drive transmission from the main gear 8, but the return operation of the rack 13 and printing operation occur in the first half of the rotation, and the carry operation continues in the second half of the rotation. It is starting to be done. That is, when the print/carry shaft 10 rotates in the direction of arrow C, the carry cam 60 spline-coupled thereto also rotates together. As shown in FIGS. 9A and 9B, at the beginning of the rotation of the carry cam 60 in the direction of arrow H, the return lever part 6 is moved by the easy rotation part 64.
7 in the direction of arrow I, the rack 13 returns to its original position, and the rack teeth 6 are raised as shown in FIG.
6 and the protrusion 62 mesh with each other. In this first half circumference, the circumferential protrusion 62a (see FIG. 8) is connected to the easy tooth 66.
Since the carry cam 60 (along with the hammer holder 11 and the hammer 55) is not moved, it only rotates half a turn on the spot. Halfway around the carry cam 60, the hammer drive section 61 comes into contact with the receiving section 65 of the hammer 55, as shown in FIG.
As the hammer driving section 61 continues to rotate, the hammer 55 is pushed forward against the elasticity of the tension spring.
Selected type part 21 facing paper 16
The opening 5 is opened by pushing out the hammer 55.
4 (see FIG. 7) and is pressed against the paper 16 to perform desired printing. In addition, as shown in FIG.
3, unnecessary prints such as side prints are not made. As the carry cam 60 rotates, the hammer drive section 61 moves to the first position.
By moving the hammer 55 upward from the horizontal position as shown in FIG. During this reciprocating movement of the hammer 55, the hammer 55 is properly guided by the engagement between the hammer mounting portion 50, the convex portion 57, and the guide groove 58, and the engagement between the spring hook pin 59 and the long groove 52.

When the carry cam 60 continues to rotate, the spiral protrusion 62b (see FIG.
6, and as it rotates, the hammer holder 11, hammer 55, carry cam 60, etc. move toward the upper digit (to the left in Fig. 1) by an amount equivalent to one digit against the elasticity of the hammer return spring 12, and the carry is carried up. will be done.

Although the explanation will be complicated, when the rack 13 returns as described above, the return state shown in FIG.
Stay away from 5. Therefore, only the rotary lever 46 prevents the control gear 33 and the reset plate 43 from rotating. Then, as shown in FIG.
When the locking groove 39 disengages, the control gear 33
In addition, the rotation stopper claw 68 and the claw 47 that prevent rotation of the reset plate 43 are both disengaged, and the control gear 33 is free to rotate, so that the control gear 33 is rotated as shown in FIG. is slightly rotated in the direction of arrow J by the biasing force of the tension spring 78, and the tooth portion 34 of the single gear portion 35 comes into sliding contact with the outer peripheral surface of the disc portion 29 of the sensor gear 27. This sixth
The state shown in Figure C is called the paper feed set state. At this time, the projection 45 of the reset plate 43 is in the position shown in FIG. 12B.

Here, the trigger groove 30 of the sensor gear 27 is
After the cam protrusion 31 pushes out the cam surface contact portion 48
It is designed so that when the 30th character part 21 comes, it is in a position where it meshes with the single tooth part 34 of the control gear 33. Here, the reason why we say "30th printed part" is because normally, this type of symbol part is not selected consecutively, and as shown in Figure 14, the printed part is selected after the number part. "+", "-", which may correspond to the 31st to 33rd printed characters if selected
Since "X" etc. are printed at the beginning of a line, there is no problem even if it is used as the "30th printing section", and the operation time can be shortened. Therefore, after the paper feed is set, if a printing operation is performed even once during the transfer of the type belt 3 for 30 characters, the reset plate 4 is moved back and forth in the D direction of the gear clutch lever 71 as shown in FIG. 12B.
3 rotates in the direction of arrow K, and the protrusion 45 is pushed back to the position shown in FIG. Claw portion 4 of rotating lever 46
7 is in elastic contact with the outer circumferential surface of the locking portion 40 (see FIG. 5C) of the control gear 33, so when the reset plate 43 is pushed back, the pawl of the rotating lever 46 is moved as shown in FIG. 6D. Even if the portion 47 reenters the locking groove 39 of the control gear 33 and the trigger groove portion 30 of the sensor gear 27 passes under the tooth portion 34, it does not engage, and no paper feeding operation is performed.

In this way, type selection, printing operation, carry operation,
The paper feed setting operation and its reset operation are sequentially repeated to print one line.
Next, the hammer holder return/paper feeding mechanism will be explained.

[Hammer holder return/paper feed mechanism]

As mentioned above, when one line is printed,
It is necessary to return the hammer holder 11 to the home position again and to feed the paper by an amount equivalent to one line in preparation for printing the next line.

As shown in FIG. 2, the spiral tooth portion 42 of the paper feed cam portion 41 of the control gear 33 is adapted to mesh with the intermediate gear 75. As shown in FIG. A connecting shaft 76 of the intermediate gear 75 is press-fitted into a central shaft hole 77 of the paper feed roller 14 and rotated together with the paper feed roller 14 .

If the printing operation is not performed even once during the transfer of the type belt 3 for 30 characters after the above-mentioned paper feed is set, the gear clutch lever 71 shown in FIG. Since no reset operation is performed, it is assumed that printing of that line has finished. Therefore, the paper feed is set, and when the 30th printed character arrives, the single tooth 34 of the control gear 33 is fitted into the trigger groove 30 of the sensor gear 27, as shown in FIG. 6E. Subsequently, as the sensor gear 27 rotates, the spur gear portion 28 of the sensor gear 27 and the spur gear portion 38 of the control gear 33 mesh with each other, causing the control gear 33 and the reset plate 43 to rotate once.

Before the control gear 33 rotates, that is, in a state other than paper feeding operation, the intermediate gear 75 faces the toothless portion 42c of the paper feeding cam portion 41, as shown in FIG. Therefore, during operations other than paper feeding, the intermediate gear 75 and the paper feeding roller 14
can rotate freely, the paper 16 can be attached and detached without any problem, and the control gear 33 does not shift its position.

The intermediate gear 75 is connected to the helical tooth portion 42 of the control gear 33.
If they are always in mesh with each other, the following problems will occur. That is, the paper 16 may be mounted on the paper feed roller 14, or the paper 16 may be mounted on the paper feed roller 1.
When removing the paper 16 from the paper feed roller 14 or pulling out a predetermined length of the paper 16 mounted on the paper feed roller 14, the control gear 33 rotates slightly via the paper feed roller 14 and the intermediate gear 75. This rotation causes the control gear 33, which is biased by the tension spring 78, to become unstable. Further, since the paper feed roller 14 is in a braked state, it is difficult to handle the paper 16.

As mentioned above, the spiral tooth portion 4 of the paper feed cam portion 41
Toothless portion 42 that is in a non-meshing state with intermediate gear 75 of No. 2
If c is provided, even if the paper feed roller 14 and the intermediate gear 75 rotate during handling of the paper 16, the control gear 33 will not be displaced, and the stability of the operation can be ensured.

The toothless portion 42c is designed to have a size that can sufficiently accommodate the teeth of the intermediate gear 75.
The appropriate opening angle θ (see Fig. 15) is about 60 degrees.

When the sensor gear 27 and the control gear 33 mesh and the control gear 33 rotates in the direction of arrow J as shown in FIG. 15, the spiral tooth portion 42a of the control gear 33 meshes with the tooth portion of the intermediate gear 75. The following shape is adopted to ensure smooth engagement. That is, the end edge 42d of the helical tooth portion 42a that first engages with the intermediate gear 75 does not extend radially from the root of the helical tooth portion 42a toward the tip of the tooth, but instead The end edge 42d is inclined so as to widen slightly when viewed from a plane so that the base portion meshes with the intermediate gear 75 and then the tooth tips thereof mesh with each other. Furthermore, this edge 42d is formed into a tapered shape as shown in FIG.

On the other hand, as shown in FIG.
A is provided.

The rotational force of the intermediate gear 75 is transmitted to the paper feed roller 14, and its rotation feeds the paper 16 by an amount corresponding to one line. During this paper feeding operation, as shown in FIG.
When the rack 5 has rotated about half a revolution, its protrusion 45 enters under the tapered tilting notch 69 provided in the rack 13, as shown in FIG. 11A. When the reset plate 43 further rotates in the direction of arrow E, the protrusion 45 on the opposite side of the rack teeth 66 of the rack 13
The rack 13 is pushed up in the direction of arrow L. In this way, you can easily
3 is knocked down, the rack teeth 66 and carry cam 60
The hammer holder 11 containing the hammer 55 and the carry cam 60 is returned to the home position by the tensile force of the holder return spring 12.

When the control gear 33 rotates once, the pawl 47 enters the locking groove 39 of the control gear 33 as shown in FIG. The protrusion 45 of 43 is engaged with the rotation stopper claw 68 of the folded rack 13, and is ready for printing the next row.

As mentioned before, as shown in FIG.
2a and 42b mesh with the intermediate gear 75, and the intermediate gear 75 and the paper feed roller 1 are controlled by the control gear 33.
4 rotates. The paper 16 is held between the paper feed roller 14 and the paper feed auxiliary roller 79, and the rotation of the paper feed roller 14 works together with the paper feed auxiliary roller 79 to feed the paper 16 by one line. However, the aforementioned spiral teeth 42a, 42b and the intermediate gear 75 do not mesh well, and as shown in FIG. Sometimes.
It is extremely rare for the tips of the spiral teeth 42a, 42b and the intermediate gear 75 to come into contact with each other, but for example, paper held between the paper feed roller 14 and the paper feed auxiliary roller 79 When the end of the intermediate gear 75 is held by hand and pulled out to a desired length, the intermediate gear 75 is opened at the point where the tooth tip of the intermediate gear 75 is opposite to the tooth tip of the spiral tooth portions 42a and 42b of the paper feed cam portion 41. When the gear 75 stops rotating and the control gear 33 (paper feed cam section 41) rotates next, the spiral teeth 42a and 42b may abut against the intermediate gear 75. If the paper feed cam portion 41 and the intermediate gear 75 collide in this way, not only will the paper not be fed, but parts in the power transmission system will be damaged.

In order to prevent this from happening, in the present invention, as shown in FIGS. 2 and 18, bearings 80 provided on both sides of the paper feed roller 14 are provided with
Oval holes 81 extending in the opposite direction to the side facing the control gear 33, that is, in the direction of the paper feed auxiliary roller 79, are formed respectively, and the intermediate gear 75
A connecting shaft 76 and a roller shaft 82 (see FIG. 2) protruding from one side of the paper feed roller 14 are inserted and supported, respectively. Since the paper feed auxiliary roller 79 presses against the rubber annular body 83 of the paper feed roller 14, the elasticity of the annular body 83 causes the paper feed roller 14 and the intermediate gear 75 connected thereto to move elastically toward the control gear 33. The intermediate gear 75 is energized, and normally the helical tooth portions 42a, 42b of the control gear 33 and the intermediate gear 75 mesh reliably.

When the tips of the spiral teeth 42a, 42b of the paper feeding cam section 41 and the tips of the intermediate gear 75 are brought into opposition by the manual operation as described above, the next control gear 33 (paper Due to the rotational force of the feed cam portion 41), the paper feed roller 14 is moved slightly backward in the direction of arrow M as shown in FIG. 18 with the compression of the rubber annular body 83 via the intermediate gear 75. This retraction and the rotational force of the control gear 75 (paper feed cam part 41) work together to cause the tips of the spiral teeth 42a and 42b to
The abutting contact with the tip of tooth No. 5 is released, and the two are securely engaged. Simultaneously with this engagement, the paper feed roller 14 is pushed back to its original position by the elasticity of the rubber annular body 83, and rotates normally to perform the paper feed operation.

In this embodiment, the paper feed roller 14 is elastically biased by utilizing the elasticity of the rubber annular body 83 of the paper feed roller 14, but the present invention is not limited to this. The feed roller 14 can also be elastically biased.

Figure 14 shows the arrangement of printed characters for each digit. After the paper feed is set and before the paper feed operation starts, the 30 characters of printed characters include all types of characters in every digit. There is. Therefore, if no printing operation is performed while the type belt 3 is moved for 30 characters after the paper feed is set, it means that printing of that line has been completed, and the next digit return and paper feed operation is started. In addition, when printing blank (space),
The above-mentioned digit return and paper feed operations are not performed.

The relationships among the operations described above are shown in FIGS. 19A and 19B and FIG. 20. Figure 19A here is a time chart of type selection, printing operation, carry operation, paper feed set, and its reset operation, Figure 19B is a time chart of paper feed, and Figure 20 is a flowchart of each operation. It is.

In this embodiment, the paper feed roller 14 and the intermediate gear 7
Although 5 and 5 are separate bodies, it is also possible to integrate the two.

As described above, the present invention includes a paper feed roller, an intermediate gear connected to the paper feed roller and supported so as to be able to move forward and backward, and having a spur gear portion on its outer periphery; a paper feed cam provided with a spiral tooth portion on its outer circumferential portion that is arranged in a direction and meshes with a spur tooth portion of an intermediate gear; a pressing means for elastically urging the intermediate gear toward the paper feed cam side; and a paper feed cam. The control gear rotates together with the paper feed cam and rotates in conjunction with the paper feed cam, a reset plate with a protrusion, and the type belt. A sensor gear is provided with a trigger groove into which a single tooth of the gear is inserted, and the sensor gear assumes a return position and a non-return position.
It includes a rack provided with rack teeth and a hammer that is engaged with the rack teeth and carried up, and when the type belt reaches a predetermined type position, one tooth of the control gear is inserted into the trigger groove of the sensor gear. The sensor gear and the control gear are engaged with each other by the rotation of the sensor gear, and the rotation of the control gear is transmitted to the paper feed roller via an elastically biased intermediate gear to perform a paper feed operation, During the rotation of the reset plate during this paper feeding operation, a protrusion on the reset plate moves the rack from the return position to the non-return position, releases the engagement between the rack and the hammer, and performs the return operation of the hammer. It is characterized by the following.

With such a configuration, the paper feed operation is started before the printing of a line is finished and the backward movement starts, so that the paper feed time can be substantially increased. Therefore, stable paper feeding operation is performed,
The line spacing is consistent, improving printing quality, and the spiral teeth of the paper feed cam and the intermediate gear always mesh reliably without bumping into each other, ensuring normal paper feed operation and reliability. We can provide high quality printers.

[Brief explanation of drawings]

The drawings are all for explaining a printer according to an embodiment of the present invention. Fig. 1 is a schematic configuration diagram of the printer, Fig. 2 is an exploded perspective view of essential parts of the invention, and Fig. 3 is a plan view of a type belt. Figure 4 is a bottom view of the sensor gear, Figure 5 is a diagram for explaining the control gear, Figure A is a plan view of one gear section, and Figure B is a plan view of the spur gear section. , Figure C is a plan view of the locking part, Figures D and E are a plan view and side view of the paper feed cam part, Figure F is a partially enlarged side view of the spiral tooth part,
Fig. 6 A, B, C, D, and E are explanatory diagrams showing the engagement relationship between the sensor gear, the control gear, and the rotary lever in each state; Fig. 7 is a perspective view of the hammer holder, the hammer, and the carry cam; Figure 8 is a developed view of the cam surface of the carry cam section, Figures 9A and 9B are explanatory diagrams for explaining the rack return operation, and Figures 10A and 10B are illustrations of the rotation stopping operation of the reset plate by the rack. Figures 11A and 11B are explanatory diagrams for explaining the rack tilting operation, and Figures 12A, B, and C are explanatory diagrams for explaining the engagement relationship between the gear clutch lever and the reset plate. , Figures 13A and 13B are cross-sectional views of main parts to explain the printing operation, Figure 14 is an explanatory diagram showing the arrangement of type for each digit, and Figure 15 is a diagram showing the paper feed cam section and the intermediate gear facing each other. FIG. 16 is an explanatory diagram showing the operating states of the paper feed cam section, intermediate gear, paper feed roller, and paper feed auxiliary roller.
Fig. 7 is a partially enlarged plan view showing a state where the helical tooth part of the paper feed cam part and the intermediate gear abut against each other, Fig. 18 is a side view of the main part near the bearing part of the paper feed roller, and Fig. 1
FIG. 9A is a time chart of type selection, print selection, carry operation, paper feed set, and its reset operation, FIG. 19B is a time chart of paper feed, and FIG. 20 is a flowchart of each operation. 14...Paper feed roller, 16...Paper, 33...
...Control gear, 41...Paper feed cam section, 42a, 4
2b...Spiral tooth portion, 75...Intermediate gear, 79...
... Paper feed auxiliary roller, 80 ... Bearing section, 81 ...
Oval hole, 82...roller shaft, 83...annular body.

Claims (1)

[Claims] 1. A paper feed roller, an intermediate gear connected to the paper feed roller and supported so as to be able to move forward and backward, and having spur teeth on its outer periphery, and an intermediate gear arranged in a direction perpendicular to the axial direction of the intermediate gear. a paper feed cam having a spiral tooth portion on the outer periphery that meshes with the spur tooth portion;
a pressing means for elastically biasing the intermediate gear toward the paper feed cam; a control gear that rotates together with the paper feed cam and has a single tooth on its outer periphery; and a control gear that rotates together with the paper feed cam. At the same time, a reset plate provided with a protrusion, a sensor gear rotated in conjunction with the type belt and provided with a trigger groove portion into which a single tooth portion of the control gear is fitted, and a return position and a non-return position. , comprising a rack provided with rack teeth and a hammer that is engaged with the rack teeth and carried up, and when the type belt reaches a predetermined printing position, the single tooth of the control gear is inserted into the trigger groove of the sensor gear. is fitted, and the rotation of the sensor gear engages the sensor gear and the control gear, and the rotation of the control gear is transmitted to the paper feed roller via an elastically biased intermediate gear to perform a paper feed operation. During the rotation of the reset plate during this paper feeding operation, a protrusion on the reset plate moves the rack from the return position to the non-return position, releases the engagement between the rack and the hammer, and causes the hammer to return. A printer characterized by: