JPH0326146B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small serial printer, and more particularly, includes a type drum rotatably mounted on a carriage about an axis parallel to the feeding direction of printing paper; The carriage is given a force to return to the home position by a spring force. It concerns a small serial printer.

Conventional serial printing type printers place the type drum vertically relative to the printing paper, that is, with the rotation axis horizontal, and the rotational movement of the type drum,
Printing was performed by a stop action, an impact action, and a carry action, and the paper feed action was performed after one line of printing was completed.

On the other hand, a serial printer is known in which the type drum is mounted around an axis perpendicular to the digit direction of the printing paper, and the type drum is conveyed in the digit direction of the printing paper.

This printer has a vertically arranged type drum with a type belt for printing symbols and a type belt for printing numbers, and prints by selectively operating one of them.

Further, in this type of printer, the force for returning the carriage to the home position is normally provided by a spring.

Several mechanisms have been proposed to return the carriage to its home position.
Both had complicated structures and many malfunctions, so there was room for improvement.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a small-sized serial printer configured so that the carriage can be reliably returned to its home position.

In order to achieve the above object, the present invention includes a type drum that can rotate around an axis parallel to the feeding direction of printing paper, and a carriage that conveys this type drum in the direction of the printing column. In a small serial printer, a cam plate that engages with a carriage along the reciprocating path of the carriage is provided with a spring that gives it the ability to rotate in a direction in which it always engages with the carriage, and a leaf spring that locks one end of the cam plate. is provided, and when the carriage returns, the cam plate and the carriage are rotated and held in a state in which they are not engaged by the leaf spring, and when the carriage returns to the home position, the cam plate is returned to its original state. It was configured to allow

Hereinafter, details of the present invention will be explained based on embodiments shown in the drawings.

FIG. 1 schematically shows the overall structure of a small serial printer according to the present invention, and the small serial printer according to the present invention is assembled based on a frame 1 in the form of a housing. A motor 2 and a solenoid 3 are attached to one end of the frame 1 and serve as a trigger for driving a control mechanism, which will be described later. The output shaft 4 of the motor 2 extends outward beyond the left side plate 1a of the frame 1, and has a pulley 5 fixed to its tip. A rotary shaft 6 is rotatably supported on the frame 1 parallel to the output shaft 4, and a pulley 7 is fixed to the outer end of the rotary shaft 6.
A belt 8 is stretched between the motor 2 and the
It transmits the rotation of A tachometer generator coil 1 includes a tachometer generator magnet 9 that rotates together with a rotating shaft 6 inside a pulley 7.
0 is attached to detect timing pulses representing the position of the type on the type drum 16.

As shown in FIG. 2, a worm gear 11 is fixed in the middle of the rotating shaft 6.
is rotatably supported on the frame 1 via a shaft 13b, and is always in mesh with a drum gear 13 which is integrated with the type drum 16. As shown in FIG. 3, a part of the carriage 12 is provided with a contact piece 14 for detecting a reset pulse signal.
Its tip faces a position where it can engage with a protrusion 13a protruding from the side surface of the drum gear 13.

As shown in FIG. 4, the drum gear 13 is provided on the lower surface of the carriage 12 guided by guide shafts 15, 15, and a type drum 16 is rotatably supported on the upper side of the carriage 12 coaxially with the drum gear 13. has been done. The type drum 16 has a cylindrical base 16a as shown in FIG.
A type belt 16b for numbers and a type belt 16c for symbols are wrapped around each other, and the rear end side of each type belt faces the inside of the base through a through hole made in the base 16a. . Also, add 2 blank type parts.
It has characters.

Above the type drum 16 is a hammer unit 17.
is located. The hammer unit 17 consists of a hammer 18 for printing numbers located on the lower side and a hammer 19 for printing symbols located on the upper side.As shown in FIG. is rotatably supported by a support shaft 20. As is clear from FIG. 6, the number printing hammer 18 has an arm 18a extending above the type drum 16, and a printing roller 21 is rotatably supported on the lower surface of the tip of the arm 18a, 16 and faces the type belt 16b for numbers. The other arm 18b of this hammer 18
The tip of the cam plate 22 has an L-shaped cross section and is suspended horizontally between the rotary shaft 6 and the motor 2.
It faces a position where it comes into contact with a protrusion 23 protruding from the inside of the base of 2a.

The symbol printing hammer 19 is fitted into the type drum 16 by bending the tip of one arm 19a.
A roller 24 is rotatably supported at its tip at a position below the roller 21 and facing the symbol type belt 16c. Further, the tip of the other arm 19b is connected to the vertical portion 22a of the cam plate 22.
It faces a position where it can engage with the protrusion 25 located above the protrusion 23 . Note that these protrusions 23 and 25 have a simple triangular cross section,
It is configured so that the arms 18b and 19b can ride on it from either the left or right direction.

Further, on the outer edge of the horizontal portion 22b of the cam plate 22, a plurality of substantially triangular protrusions 26 with the hammer unit side serving as an upright wall in FIG. 6 are formed in a sawtooth shape. As shown in FIG. 3, these protrusions 26 are engaged with claws 32a at the tips of elastic arms 32 protruding from one end of the carriage 12.

Furthermore, a type drum 16 is mounted on the carriage 12.
As shown in FIG. 1, an ink roller 27 is rotatably supported in the vicinity of the type drum 16, and is always in contact with the type drum 16 to apply ink.

On the other hand, as shown in FIG. 7, the cam plate 22 is supported on a shaft 28 via a bracket 22c protruding from its lower end, and is set to be able to rotate freely within a certain angular range. , a spring (not shown) provides a clockwise rotation behavior in FIG.

The reference numeral 29 in FIG. 1 is a return spring, one end of which is fixed to one end of the carriage 12 as shown in FIG. It passes through the platen 30 along with a guide 31 having a groove, and is fixed to the other side plate 1a, giving the carriage 12 the habit of always moving rightward in FIG. However, when the claw 32a of the carriage 12 is engaged with the upright wall side of the protrusion 26 of the cam plate 22 as shown in FIG. 3, the movement of the carriage is restricted.

As shown in FIG. 2, a drive gear 33 is always meshed with the drum gear 13, and the drive gear 33 is rotatably supported on a shaft 34.

As shown in FIG. 3, one end of a control lever 35 is rotatably supported on the rotating shaft 34 below the drive gear 33, as shown in FIG. The rotation habit is given in the middle counterclockwise direction. The tip 35a of the control lever 35 is located on the side of the carriage 12 at a position where it can engage with a rack tooth 37a of a rack plate 37 arranged parallel to the horizontal portion 22b of the cam plate 22. Further, the drum gear 13 can also engage with the rack teeth 37a, and the rack plate 37 is rotatably supported through a shaft 38 of the right side plate 1b in FIG. 1 within a certain angular range.

As shown in FIG. 1, this rack plate 37 is formed into a substantially U-shape as a whole, and is guided to the outside of the right side plate 1b, under the platen 30, and to the outside of the left side plate 1a. It is supported by a shaft (not shown) that projects outward from the side plate 1a on the same axis as the shaft 38. In addition, the rack plate 37
A rack plate lever 39 is integrally formed on the side plate 1b side at a position beyond the shaft 38, and a spring 40 is stretched between the tip 39a and the upper end of the side plate 1b. The entire plate 37 is the first
In the figure, it has been given the habit of turning clockwise. A protrusion 39b provided above the distal end of the rack plate lever 39 is in contact with the distal end of the armature 41 of the solenoid 3.

On the other hand, printing paper P is guided upward between the platen 30 and the type drum 16 while being held down by a paper guide 42. This platen 30
At the lower right side in FIG. 1, a clutch gear 43 is rotatably supported on a shaft 44, which meshes with the drive gear 33 as shown in FIG. 2 when the carriage 12 is at the right end.

As shown in FIG. 8, the clutch gear 43 has a boss portion 43a wrapped around a coil spring 45 constituting a spring clutch.
a is fixed to the PF (abbreviation for paper feed, hereinafter the same) worm 46 side, and the other end 45b projects outward from the bottom of the PF worm 46 and is rotatable via a shaft 47 near the clutch gear 43 It is in a state where it can engage with the tip end 48a of the PF lever 48 which is supported by the shaft. The PF worm 46 is formed in a cylindrical shape, and is fitted on the outside of the coil spring 45 as shown in FIG. 8, and is rotatably supported on the shaft 44.

The worm part 46a of the PF worm 46 meshes with the PF gear 49 as shown in FIG.
The PF gear 49 is the rubber roller 5 that sends out the printing paper.
It is fixed to a shaft 51 that is integral with 0. A small-diameter pinch roller 52 is in contact with the lower side of the rubber roller 50, and the printing paper P is guided between them and sent upward by the rotation of the rubber roller 50 via the PF gear 49.

On the other hand, as shown in FIG. 1, a leaf spring 53 which is approximately U-shaped and bent into an L-shape is fixed to a part of the right side plate 1b. The ends 53a and 53b are connected to the cam plate 22.
It is located at a position where it is engaged with a protrusion 54 protruding from the right end of the holder.

Next, the operation of the printer according to the present invention configured as above will be explained.

When the switch is turned on, the rotation of the motor 2 shown in FIG. It will be in a state where it will rotate continuously in a clockwise direction.

In this state, a printed character is selected and the armature 41 is pulled by energizing the solenoid 3, pushing the protrusion 39b of the rack plate lever 39, and the rack plate 37 rises from the state shown in FIG. 4 to the state shown in FIG. When the rack teeth 37a and the drive gear 33 are in mesh with each other, the rack plate 37 is in a fixed state, so the drum gear 13 moves forward due to its rotational force against the tensile force of the return spring 29, and the type drum 16 rotates. While moving to the left in Figure 1,
A carry movement is performed.

At this time, since the hammer unit 17 integrated with the carriage 12 also moves, the tip of the arm 18b of the hammer 18 for printing numbers, for example, rides on the protrusion 23 of the cam plate 22, as shown in FIGS. 18 is rotated counterclockwise in FIG. Printing is performed by pressing. At this time, if the surface of the pressed letters deviates even slightly from the printing paper P, dirt or ghosts will occur during printing, so the drum gear 13
It is preferable to arrange the platen 30 at a position such that the extended surface of the printing paper P contacts the pitch circumference of the printing paper P. By arranging them in this manner, printing can be performed while the selected characters on the character belt 16b are in perfect rolling contact with each other in a protruding state. When the tip of the arm 18b of the hammer 18 passes over one of the protrusions 23, the hammer 18
Then, the type belt 16b returns to its original state as shown in FIG. 11, and printing for one digit is completed. At this time, if the solenoid 3 is left on, the rack plate 37 and the drum gear 13 will not come off, and the carriage 12 will carry on to the next carry, and the next cam protrusion 23 will move the character next to the one that has just finished printing. Print the typeface. When printing other characters next time, disengage the rack plate 37 and drum gear 13 by turning off the solenoid 3, and return to the state shown in FIG.
7a and the tip 35a of the control lever 35 engage, resulting in the state shown in FIGS. 13 to 14, the drum gear 13 idles, and the carry-up movement of the carriage 12 is stopped. At the same time, the claw 32 of the carriage 12
a catches on the protrusion 26 of the cam plate 22 and does not return to its original position even when the tensile force of the return spring 29 is applied, and the carriage 12 stops at that position. When the next printed character is selected, the solenoid 3 is turned on and the same operation as above is performed.

The information that informs the control circuit of the position of the character to be printed is the initial position signal generated by the contact between the protrusion 13a and the contact piece 14 shown in FIG. 3, and the tachometer generator magnet 9 and coil shown in FIG. 1
0, and when the control circuit turns on the solenoid 3 based on these two signals, the armature 41 pushes down the rack plate lever 39, and the rack plate 37 moves to the first position around the shaft 38.
The rack plate 37 is rotated counterclockwise in the figure, and the rack plate 37 rises from the state shown in FIG. 4 to the state shown in FIG. 10. When the condition shown in FIG. 10 is reached and the rack teeth 37a mesh with the drum gear 13 and the carriage 12 begins to move, the tip 35 of the control lever 35
a overlaps the rack tooth 37a in a vertically shifted state, and at this time, even if the solenoid 3 is de-energized, the control lever 35 and the rack tooth 37a do not engage with each other, and after printing one digit, the 14th The carriage 12 stops only when it reaches the state shown in the figure. That is, the role of the control lever 35 is to prevent the rack teeth 37a from disengaging from the drum gear 13 during printing, to ensure printing for one digit, and to prevent the carriage 12 from overrunning. .

Next, the selection operation between symbol digit printing and numerical digit printing will be explained.

When the carriage 12 is at the rightmost home position as shown in FIG. 1 at the start of printing, the drive gear 33 and clutch gear 43 are engaged and rotated as shown in FIG. 2 when the carriage is viewed from the back side. is in a state of being.

In this state, one end 45b of the coil spring 45
Since the clutch gear 43 is engaged with the tip 48a of the PF lever 48 and the coil spring 45 is in a relaxed state, the rotation of the clutch gear 43 is not transmitted to the PF worm gear 46. Assuming that this position is the home position of the carriage, the first energization of the print solenoid 3 causes carry to be carried out as described above and printing to be performed at the same time.At this time, the cam plate 2
As shown in FIG. 6, there is only one upper protrusion 25 that engages with the hammer 19 for symbol printing, and there is only one protrusion 25 below the protrusion 25 so as not to engage with the hammer 18 for number printing. There is no protrusion 23 on the side.

Therefore, the first print always becomes a symbol, and during carrying, the protrusion 12a of the carriage 12 engages with the other end 48b of the PF lever 48, and the PF lever 48 is rotated counterclockwise in FIG. 45
When the one end 45b and the one end 48a of the PF lever 48 are disengaged, and the state shown by the chain line in FIG. 2 is reached, the coil spring 45 is wound around the boss 43a, and the PF worm 46 is rotated by this force. However, the protruding portion 12a of the carriage immediately moves to the PF lever 48.
The PF lever 48 immediately returns to its original position due to the force of a spring (not shown), and the PF worm 46 rotates once, causing one end of the 4
8a re-engages one end 45b of the coil spring 45, so that the coil spring 45 is relaxed and the spring clutch is turned off. Therefore, the PF worm 46 rotates exactly one rotation, rotates the PF gear 49, rotates the rubber roller 50, and feeds the printing paper P by half a pitch.

In this way, the previously printed symbol is raised to the same level as the next digit, allowing the symbol and digit to be printed without having to move up and down during printing, as is often the case with typewriters. Can be printed on the same line.

By the way, when printing is performed sequentially in this manner and all numeric digits have been printed and the carriage 12 comes to the leftmost position in FIG.
and a projection 22d formed on the left end of the cam plate 22 toward the carriage come into contact with each other, and the cam plate 22 is rotated counterclockwise as shown in FIG. 7 against the force of a spring (not shown). . As a result, the state in which the protrusion 54 of the cam plate 22 is engaged with the bent portion 53a of the leaf spring 53 as shown in FIG. 16 changes, and the protrusion 54
4 moves to the left in the figure, the protrusion 54 is locked inside the bent portion 53a of the leaf spring 53, and holds the cam plate 22 in that position. In this state, the carriage 12
Since the engagement between the arm 32 and the protrusion 26 of the cam plate 22 is disengaged, the carriage 12 is pulled back to the right end in FIG. 1 by the tensile force of the return spring 29. In this retracting operation, the spring force of the return spring 29 is set to be stronger than the spring force of the spring 36 pressing the control lever 35 against the rack plate 37 in FIG. The one end 48d of the PF lever 48 is again rotated counterclockwise in FIG.
When No. 2 returns to the home position, the paper is fed a second time by half a pitch, and the paper is fed a total of 1 pitch.

Also, when the carriage 12 returns to the home position, the protrusion 12 on the right end of the carriage 12
b is the tip 53 of the leaf spring 53 as shown in FIG.
At point b, the engagement between the bent portion 53a and the protrusion 54 is disengaged, so that the cam plate 22 is rotated clockwise in FIG. 7 by a spring (not shown) and returns to its original state.

In this way, one printing cycle is completed.

On the other hand, if the carriage 12 is to be returned halfway without printing over all digits, it is necessary to perform a slightly different operation from that described above. That is, a protrusion 16e is provided inside the base 16a of the type drum 16 as shown in FIG. 19, and the position of the protrusion 16e is set at a position where no printing is performed.

Then, the roller 21 of the hammer 18 hits this protrusion 1.
When trying to print by turning on the solenoid 3 at position 6e, the rotation of the hammer 18 is caused by the protrusion 16e.
When the arm 18b and the protrusion 23 meet, the arm 18b does not move, and the protrusion 23 escapes, pushing the cam plate 22, and the cam plate 22 rotates in the same way as described above. As shown in FIG.
The carriage 1 is locked by the bent portion 53a of the carriage 1.
2 returns to the home position and one printing cycle is completed.

In addition, when only feeding the paper without printing, by turning on the solenoid twice for the protrusion 16e in the type drum 16, the paper will be fed by one pitch and the carriage will return to the home position. .

In addition, in the above-mentioned embodiment, the type drum 1
When dividing the type in the circumferential direction of 6, the number of teeth of the drum gear 13 is the same 1:1, but the number of teeth may be an integral multiple of the number of divisions of the type drum.

Further, in the above embodiment, the belt 16b for printing numbers and the belt 16c for printing symbols are separate, but may be wound together as one body.Furthermore, the number of character belts may be increased, for example, in three rows. year,
It is also possible to arrange the ink rollers 27 in two colors, red and black, one above the other, so that two-color printing can be performed.

As is clear from the above description, according to the present invention, a cam plate is provided which is given the habit of rotating in the direction of constantly engaging the carriage along the reciprocating path of the carriage, and one end of the cam plate is locked. A leaf spring is provided to prevent the carriage from engaging with the cam plate during the return operation of the carriage.
Since a structure is adopted in which the engagement between the leaf spring and the carriage is released when the carriage returns to the home position, the movement of returning the carriage to the home position can be reliably performed with an extremely simple structure.

[Brief explanation of drawings]

The figure explains one embodiment of the present invention.
The figure is a perspective view to explain the overall structure, Figure 2 is a bottom view to explain the gear group attached to the back side of the carriage, Figure 3 is a bottom view of the carriage, and Figure 4 is a vertical view of the type drum. 5 is a cross-sectional plan view of the type drum, FIG. 6 is a perspective view showing the interlocking relationship between the printing hammer and the cam member, and FIG. 7 is the carriage girder. 8 is a vertical sectional side view of the spring clutch; FIG. 9 is a side view illustrating the paper feeding mechanism; FIG. 10 is a side view illustrating the operation of the carriage drive control mechanism; FIGS. 11 and 12 are explanatory diagrams showing the printing operation of the hammer, respectively. FIGS. 13 and 14 are explanatory diagrams showing the interlocking relationship between the printing paper supply lever, the drum gear, and the rack plate that is the control member. FIG. 15 1 is a side view of a main part for explaining the carriage return operation, and FIGS. 16 to 19 are explanatory diagrams each showing the control operation of the cam member during the return operation. 2...Motor, 3...Solenoid, 6...Rotating shaft, 1
1...worm gear, 12...carriage, 13...drum gear, 16...type drum, 16a...base, 1
6b... Type belt for numbers, 16c... Type belt for symbols, 18... Hammer for number printing, 19... Hammer for symbol printing, 22... Cam plate, 23, 25... Protrusion, 3
3... Drive gear, 37... Rack plate, 39... Rack plate lever, 43... Clutch gear, 45... Coil spring, 46... Paper feed worm, 48... Paper feed lever, 49... Paper feed gear, 50... Rubber roller.

Claims (1)

[Claims] 1. In a small serial printer equipped with a type drum that can rotate around an axis parallel to the printing paper feeding direction and a carriage that conveys this type drum in the direction of the printing column, A cam plate is provided so as to rotate in the direction in which it is always engaged with the carriage by means of a spring, and a leaf spring is provided to lock one end of the cam plate. A small serial device characterized in that a cam plate and a carriage are held in a rotated state in which they do not engage, and the cam plate is returned to its original state when the carriage returns to its home position. printer.