JPS6358096B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing device, particularly a serial printer, and an object of the present invention is to provide a printing device that can accurately print in a proper position.

Recent calculators have become more multi-functional and sophisticated, and there are more types of input keys for scientific calculators, program calculators, etc. Therefore, as a printing device built into this type of calculator, it is desired to develop a printing device that is capable of alphanumeric printing and also performs matrix printing because the printed data is clear.

The present invention has been made in view of these points,
Examples will be described below with reference to figures.

FIG. 1 is a diagram for explaining the schematic configuration of a printing device. Between the side plates 1a and 1b, which are part of the frame of the printing device, a type wheel selection cam shaft 2, a type shaft 3, a print/carry shaft 4, and a rack 5 are installed in order from the front side as viewed in the figure. It is rotatably constructed at intervals of
A paper feed shaft is rotatably installed below the carry shaft 4.

A carriage 7, which is stretched between the type wheel selection camshaft 2 and the type shaft 3, is held slidably along these axial directions, and is moved to a home position (starting position) near the side plate 1a by a carriage return spring 8. It is always elastically biased towards the feed position) side. Inside the carriage 7, a slider frame 11, which is stretched between the type wheel selection camshaft 2 and the type shaft 3, is disposed so as to be slidable in the axial direction like the carriage 7. Inside the slider frame 11, a type ring group 1 consisting of four type wheels 9a to 9d spline-coupled to the type shaft 3 is provided.
0 and a type wheel selection cam 12 spline-coupled to the type wheel selection cam shaft 2 are held. A type ring group return spring 13 loosely fitted to the type shaft 3 between the carriage 7 and the slider frame 11 causes the type ring group 10 and the type wheel selection cam 12 to be directed to the reference position on the side plate 1a side via the slider frame 11. is always pressed.

Since the type wheel selection cam 12 is spline-coupled to the type wheel selection cam shaft 2 as described above, it can rotate integrally with the shaft 2 and slide along the axial direction. is cam groove 1
4 is formed. Although not shown, the cam groove 14 is composed of a deformed helical sending cam groove and a return cam groove bent in the middle. Both cam grooves communicate with each other, and the feed cam groove covers 3/4 of the circumferential direction (0° to 270°) of the type wheel selection cam 12, while the return cam groove covers the circumferential direction of the type wheel selection cam 12. Each is provided over a quarter of the circumferential direction (270° to 360°).

As shown in FIG. 1, the carriage 7 is provided with a protrusion 15 that fits into the cam groove 14 of the type wheel selection cam 12, and when the type wheel selection cam 12 is rotated, the protrusion 15
5 and the pressing force of the type wheel group return spring 13, the slider frame 11 holding the type wheel group 10 and the type wheel selection cam 12 moves back and forth in the left and right direction within the carriage 7.

That is, in the initial state, the slider frame 11 is pushed to the leftmost side of the carriage 7 by the pressing force of the type ring group return spring 13, and the protrusion 15 engages with the cam groove 14 at a position on the tip side of the feed cam groove. are doing. In this state, the first type ring 9a is
It faces the hammer 16 in the hammer/carry cam holder 19 supported by the print/carry shaft 4 with the paper 17 interposed therebetween. The position where the first type wheel 9a faces the hammer 16 in this manner is referred to as the reference position of the type wheel group 10 (see FIG. 1).

Next, when the type wheel selection cam 12 is rotated 90 degrees in a predetermined direction by the type wheel selection cam shaft 2, the slider frame 11 is returned to the type wheel group by the guidance of the protrusion 15 that is fixed to the type wheel selection cam 12. Spring 1
3 is shifted to the right by a predetermined amount in FIG. When the type wheel selection cam 12 is further rotated 90 degrees in the same direction, the type wheel group 10, slider frame 11, and type wheel selection cam 12 are all shifted to the right by a predetermined amount in the same way as described above, and the third type The ring 9c faces the hammer 16. Furthermore, by rotating the type wheel selection cam 12 by 90 degrees in the same direction, that is, by rotating the type wheel selection cam 12 by 270 degrees from the start of rotation, the type wheel group 10 is shifted to the fourth type wheel 9d. can be opposed to the hammer 16. Such type ring group 1
The feed of 0 is performed while the protrusion 15 is sliding in the feed cam groove of the type wheel selection cam 12, and therefore, which type wheel 9 is to be opposed to the hammer 16 is determined by the type wheel selection cam 12 ( The selection can be made by adjusting the rotation angle of the type wheel selection camshaft 2).

When the type wheel selection cam 12 is further rotated in the same direction from the state where the fourth type wheel 9d is facing the hammer 16, the protrusion 15 moves from the feed cam groove to the return cam groove. Since the direction of the return cam groove is opposite to that of the feed cam groove, by subsequently rotating the type wheel selection cam 12 through 90 degrees in the same direction, the protrusion 15 returns to the tip of the feed cam groove. That is, by sliding the protrusion 15 in the return cam groove, the type wheel group 10, the slider frame 11, and the type wheel selection cam 1
The collection with 2 returns and the first type wheel 9
a faces the hammer 16 again. Since the type wheel selection camshaft 2 (type wheel selection cam 12) rotates only in a fixed direction, the feeding and return of the type wheel group 10 are repeated alternately, and the type wheel 9 is selected during this period.

As shown in FIG. 1, a type wheel position sensor 18 is fixed to the left end of the type wheel selection camshaft 2, which detects which type wheel 9 is currently facing the hammer 16 and the position of the type wheel 9. A condition is detected. Further, as shown in FIG. 1, a type position sensor 25 and a type reference position sensor 26 are fixed to the right end of the type wheel 3.

As shown in FIG. 1, a hammer/carry cam holder 19 is slidably held on the print/carry shaft 4, and a hammer 16 and a carry cam 20 are arranged inside the hammer/carry cam holder 19. The carry cam 20 is splined to the print/carry shaft 4 and its type ring group 10
A hammer 16 is extrudably held on the side opposite to.

As shown in FIGS. 2, 3, and 4, the carry cam 20 has two protrusions 2 on its outer circumference at 180° intervals.
1 is formed. This protrusion 21 includes a circumferential protrusion 21a extending in the circumferential direction provided over approximately 1/4 of the circumferential direction of the carry cam 20, and a circumferential protrusion 21a provided over approximately 1/4 of the circumferential direction of the carry cam 20. The protrusions 21a and 21b are continuous. The protrusions 21 of the carry cam 20 are designed to mesh with rack teeth 22 provided on the rack 5, as shown in FIG. The rack tooth 22 is the fifth
As shown in the figure, it has a truncated conical shape and has a rack of 5
They are arranged in rows at equal intervals along the longitudinal direction.

As shown in FIG. 1, the carriage 7 is connected to a hammer/carry cam holder 19 by a rope (string body) 24 stretched through six rollers 23a to 23f. Therefore, the carriage 7
are adapted to move in the same direction and by the same amount in synchronization with the hammer/carry cam holder 19.
As mentioned above, the carriage 7 is always urged toward the home position by the carriage return spring 8, so the protrusion 2 of the carry cam 20 is normally biased by this influence.
1 meshes with the rack teeth 22 in an elastic manner.
Then, when the print/carry shaft 4 (carry cam 20) is rotated 1/4 in the direction of arrow A as shown in FIG.
At first, the rack teeth 22 are in sliding contact with the circumferential protrusion 21a, so the carry cam 20 is not moved and only rotates 1/4 of a turn on the spot. Continue printing/
Move the carry shaft 4 (carry cam 20) 1/1 in the direction of arrow A.
After four rotations, this time the next rack tooth 22 of the one that was in contact with the circumferential protrusion 21a,
The spiral protrusion 21b of the other protrusion 21 comes into sliding contact, and as it rotates, the carry cam 20 moves toward the side plate 1b by an amount equivalent to one digit, that is, in the direction of arrow B in FIGS. 1 and 4. Move to.

The hammer 16 is arranged together with a carry cam 20 in a holding body 19, while the carriage 7 is connected to the holding body 19 via a rope 24.
Therefore, the carry cam 20 is moved by the arrow B corresponding to one digit.
When moving in this direction, the carriage 7 and the hammer 16 are thereby also transported in the same direction and by the same amount.

As shown in FIG. 1, the torque of the motor 27, which always rotates in one direction, is applied to the type shaft 3 via the type selection clutch 28, and to the type wheel selection camshaft 2 via the type wheel selection clutch 29. The signals are also transmitted to the print/carry shaft 4 via the print/carry clutch 30, respectively. The rotation transmission between the type selection clutch 28 and the print/carry clutch 30 is switched by the first switching member 31, and the rotation transmission between the type wheel selection clutch 29 and the print/carry clutch 30 is switched. is appropriately performed by the second switching member 32. The first switching member 31 is operated by the first electromagnet 33, and the second switching member 32 is operated by the second electromagnet 3.
4 respectively.

As shown in FIG. 1, a rack raising member 35 connected to the print/carry shaft 4 by a spline is held near the inner surface of the side plate 1a of the print/carry shaft 4. As shown in FIG. 6C, the rack raising member 35 is a cylindrical rack stopper that has an outer diameter that can come into contact with the rack teeth 22 and whose axial width is longer than the interval between the rack teeth 22. Pipe part 36
, and one scraping tooth 37 is provided integrally on the side plate 1a side of the rack stopper pipe portion 36 and is provided on the outer periphery.
It has a scooping tube part 38 which is provided protrudingly. A pressure spring 39 having an elastic force smaller than the tensile force of the carriage return spring 8 is provided between the rack lifting member 35 of the print/carry shaft 4 and the side plate 1a.
is loosely fitted, and the rack lifting member 35 is always elastically biased in the direction of arrow B.

On the other hand, on the outer periphery of the end of the rack 5 near the side plate 1a, there is a rack raising member 3 as shown in FIG.
5 is located closest to the side plate 1a, a protruding easy return tooth 40 is provided which engages with the rake tooth 37 of the tooth. A toothless portion is formed between the rack return tooth 40 and the leftmost rack tooth 22 with an interval longer than the width of the rake tooth 37.

Next, the operations of the rack 5, carry cam 20, rack raising member 35, etc. of this printing device will be explained with reference to FIG.

When one line of printing is started, the carriage 7 and the hammer/carry cam holder 19 are kept at the home position by the tension of the carriage return spring 8. In this state, as shown in FIG. 6A, the hammer/carry cam holder 19 presses the easy raising member 35 against the side plate 1a, and the pressing spring 39 is compressed because its elastic force is smaller than that of the carriage return spring 8. It is becoming a state. At this time, the rake tooth 37 and the rack return tooth 40 are in a state where they can be engaged, and the print/carry shaft 4 is reversed as shown in FIG. 6D in conjunction with the paper feeding operation in the home position. The rack 5 is rotated clockwise by a predetermined angle, and the rake teeth 37 return the rack 5 to the position where the rack teeth 22 engage with the protrusions 21 of the carry cam 20.

While the type to be printed is selected by the type wheel position sensor 18 and type position sensor 25 (see Fig. 1) and sequential printing and carry operations are performed, that is, the hammer/carry cam holder 19 is Arrow B away from the scraping member 35
When moving in the direction (in the direction of the upper digits), the rack raising member 35 is also pushed in the direction of arrow B by the restoring force of the pressing spring 39. However, as shown in FIG. 6B, the outer edge of the rack stopper tube 36 comes into contact with the leftmost rack tooth 22, and does not advance toward the upper digits. This easy raising member 35
As the tooth moves, the engagement between the rake tooth 37 and the rack return tooth 40 is released, and the rake tooth 37 faces the toothless portion between the leftmost rack tooth 22 and the rack return tooth 40. Therefore, even if the rack raising member 35 rotates together with the print/carry shaft 4, it will not collide with the rack 5, and the carry operation will be performed properly.

When one line of printing is completed and the carriage 7 is returned, the rack 5 is rotated in a predetermined direction, thereby causing the rack teeth 22 and the protrusion 2 of the carry cam 20 to rotate.
1 is released, and the leftmost rack tooth 22 is removed from the rack stopper tube portion 36. Therefore, the rack lifting member 35 is pushed toward the upper digit by the pressing spring 39, and as shown in FIG.
It will be in the state below 2. Therefore, until the hammer/carry cam holder 19 is returned to the home position by the tensile force of the carriage return spring 8, even if the rack 5 attempts to return to its original position due to vibration or the like, the rack teeth will not work. 22 comes into contact with the circumferential surface of the rack stopper pipe portion 36 and cannot return.
Due to the stopper function of the rack stopper pipe 36, the disengaged state between the rack teeth 22 and the carry cam 20 can be maintained reliably, and the return of the hammer/carry cam holder 19 can be performed smoothly without getting caught. It collides with the rack lifting member 35 and returns to the home position along with it. Even after the carriage return is completed, the rack 5 continues to rotate, and returns to its original position in connection with the paper feeding operation to the next line, as explained in Fig. 6 (a) and (d). , the rack 5 and the carry cam 20 are engaged with each other.

In order to further improve the degree of alignment of the print lines printed on the paper 17, the design is such that the play in the shafts 2, 3, 4 of the carriage 7, type ring group 10, carry cam 20, etc. is minimized. Therefore, for example, when the printing device is used at low temperatures, the carriage 7, type ring group 10, carry cam 20, etc. do not return easily, and the carriage return operation takes time. If the rack 5 is returned to its original position before the carriage return is completed, the carry cam 20 will get caught in the middle of the rack 5, and the printing position on the paper 17 will be different.

As described above, the present invention includes a carriage that holds a type carrier and is movable in the carry direction, a rack that has a large number of rack teeth along the carry direction of the carriage and is rotatable in a predetermined direction, and a carry cam that faces the rack and engages with the rack teeth and rotates to transport the carriage in the carry direction; and a carriage return means that returns the carriage to a starting position, the carriage returning to a predetermined position. When the carriage is carried up, the rack rotates to release the engagement with the carry cam, and the carriage is returned to the starting position by the carriage return means. A rack raising member is installed, which includes a raising tube portion having a protruding return tooth, a raising tooth protruding to engage with the rack return tooth, and a rack stopper tube portion having an outer circumferential portion abutting the rack tooth. , when in a state other than the carriage return, the rack raising member is kept in standby at a position where the rack return teeth and the raising teeth do not engage, and the rack rotates during carriage return and engages the carry cam. When the engagement of the carriage is released, the rack lifting member is moved to a position where the rack stopper pipe opposes a part of the rack tooth to maintain the disengaged state of the rack with respect to the carry cam, and the carriage moves near the starting position. When the rack returns to the position, the rack is moved to a position where the raising teeth engage with the rack return teeth, and the rack is rotated to the position where the rack is engaged with the carry-up cam by the operation of the rack raising member. It's summery.

Therefore, there is plenty of time before the carriage return starts and the rack returns to its original position.
The rack does not return midway, and the rack can be rotated and engaged with the carry cam after the carriage and carry cam have completely returned to their home positions, eliminating the above-mentioned inconvenience. , it prints accurately in the correct position even at low temperatures.

[Brief explanation of drawings]

The figures all show a printing device according to an embodiment of the present invention, and FIG. 1 is a schematic configuration diagram of the printing device, and FIGS. 2, 3, and 4 are a plan view and a front view of a carry cam. , a developed view of the cam surface, and Figure 5 is a plan view of the rack.
6A, B, C, D, H, and F are operation explanatory diagrams for explaining the operation of the rack raising member. 5... Rack, 7... Carriage, 8... Carriage return spring, 9a-d... Type wheel, 10
. . . Type ring group, 20 . . . Carry cam, 21 . . . Protrusion, 22 .
Raising tooth, 38... Raising pipe portion, 39... Pressing spring, 40... Easy return tooth.

Claims (1)

[Claims] 1 A carriage that holds a type carrier and is movable in the carry direction, a rack that has a large number of rack teeth along the carry direction and is rotatable in a predetermined direction, and a rack that faces the rack and is movable in the carry direction. A carry cam that engages and rotates to transport the carriage in the carry direction, and a carriage return means that returns the carriage to the starting position, and when the carriage is carried up to a predetermined position, the In a printing device in which a rack is rotated to be disengaged from a carry cam and the carriage is returned to a starting position by the carriage return means, a rack return tooth is provided protrudingly at an end of the rack; A rack raising member having a raising tube section with protruding raising teeth that engages with the rack return teeth, and a rack stopper tube section whose outer periphery abuts the rack teeth is installed, and a rack raising member is installed in a state other than carriage return. At this time, the rack raising member is kept in standby at a position where the rack return teeth and the raising teeth do not engage, and the rack rotates during carriage return and disengages from the carry cam. Then, the rack raising member is moved to a position where the rack stopper pipe faces a part of the rack tooth to maintain the disengaged state of the rack with the carry cam, and when the carriage returns to the vicinity of the starting position, the rack raising member is moved to a position where the rack stopper pipe faces a part of the rack tooth. The rack is moved to a position where it engages with the rack return tooth, and the rack is rotated by the movement of the rack raising member to the position where it engages with the carry-up cam. printing device.